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Next: <a href="#Preface" accesskey="n" rel="next">Preface</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
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<h1 class="top" id="GnuTLS"><span>GnuTLS<a class="copiable-link" href="#GnuTLS"> &para;</a></span></h1>

<p>This manual is last updated 9 February 2026 for version
3.8.12 of GnuTLS.
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<p>Copyright &copy; 2001-2026 Free Software Foundation, Inc.\\
Copyright &copy; 2001-2026 Nikos Mavrogiannopoulos
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<div class="region-contents" id="SEC_Contents">
<h2 class="contents-heading">Table of Contents</h2>

<div class="contents">

<ul class="toc-numbered-mark">
  <li><a id="toc-Preface" href="#Preface">1 Preface</a></li>
  <li><a id="toc-Introduction-to-GnuTLS" href="#Introduction-to-GnuTLS">2 Introduction to GnuTLS</a>
  <ul class="toc-numbered-mark">
    <li><a id="toc-Downloading-and-installing" href="#Downloading-and-installing">2.1 Downloading and installing</a></li>
    <li><a id="toc-Installing-for-a-software-distribution" href="#Installing-for-a-software-distribution">2.2 Installing for a software distribution</a></li>
    <li><a id="toc-Overview" href="#Document-overview">2.3 Overview</a></li>
  </ul></li>
  <li><a id="toc-Introduction-to-TLS-and-DTLS" href="#Introduction-to-TLS">3 Introduction to <abbr class="acronym">TLS</abbr> and <abbr class="acronym">DTLS</abbr></a>
  <ul class="toc-numbered-mark">
    <li><a id="toc-TLS-Layers" href="#TLS-layers">3.1 TLS Layers</a></li>
    <li><a id="toc-The-Transport-Layer" href="#The-transport-layer">3.2 The Transport Layer</a></li>
    <li><a id="toc-The-TLS-record-protocol" href="#The-TLS-record-protocol">3.3 The TLS record protocol</a>
    <ul class="toc-numbered-mark">
      <li><a id="toc-Encryption-algorithms-used-in-the-record-layer" href="#Encryption-algorithms-used-in-the-record-layer">3.3.1 Encryption algorithms used in the record layer</a></li>
      <li><a id="toc-Compression-algorithms-and-the-record-layer" href="#Compression-algorithms-and-the-record-layer">3.3.2 Compression algorithms and the record layer</a></li>
      <li><a id="toc-On-record-padding" href="#On-Record-Padding">3.3.3 On record padding</a></li>
    </ul></li>
    <li><a id="toc-The-TLS-alert-protocol" href="#The-TLS-Alert-Protocol">3.4 The TLS alert protocol</a></li>
    <li><a id="toc-The-TLS-handshake-protocol" href="#The-TLS-Handshake-Protocol">3.5 The TLS handshake protocol</a>
    <ul class="toc-numbered-mark">
      <li><a id="toc-TLS-ciphersuites" href="#TLS-Cipher-Suites">3.5.1 TLS ciphersuites</a></li>
      <li><a id="toc-Authentication" href="#Authentication">3.5.2 Authentication</a></li>
      <li><a id="toc-Client-authentication" href="#Client-Authentication">3.5.3 Client authentication</a></li>
      <li><a id="toc-Resuming-sessions" href="#Resuming-Sessions">3.5.4 Resuming sessions</a></li>
    </ul></li>
    <li><a id="toc-TLS-extensions" href="#TLS-Extensions">3.6 TLS extensions</a>
    <ul class="toc-numbered-mark">
      <li><a id="toc-Maximum-fragment-length-negotiation" href="#Maximum-fragment-length-negotiation">3.6.1 Maximum fragment length negotiation</a></li>
      <li><a id="toc-Server-name-indication" href="#Server-name-indication">3.6.2 Server name indication</a></li>
      <li><a id="toc-Session-tickets" href="#Session-tickets">3.6.3 Session tickets</a></li>
      <li><a id="toc-HeartBeat" href="#HeartBeat">3.6.4 HeartBeat</a></li>
      <li><a id="toc-Safe-renegotiation" href="#Safe-renegotiation">3.6.5 Safe renegotiation</a></li>
      <li><a id="toc-OCSP-status-request" href="#OCSP-status-request">3.6.6 OCSP status request</a></li>
      <li><a id="toc-SRTP" href="#SRTP">3.6.7 SRTP</a></li>
      <li><a id="toc-False-Start" href="#False-Start">3.6.8 False Start</a></li>
      <li><a id="toc-Application-Layer-Protocol-Negotiation-_0028ALPN_0029" href="#Application-Layer-Protocol-Negotiation-_0028ALPN_0029">3.6.9 Application Layer Protocol Negotiation (ALPN)</a></li>
      <li><a id="toc-Extensions-and-Supplemental-Data" href="#Extensions-and-Supplemental-Data">3.6.10 Extensions and Supplemental Data</a></li>
    </ul></li>
    <li><a id="toc-How-to-use-TLS-in-application-protocols" href="#How-to-use-TLS-in-application-protocols">3.7 How to use <abbr class="acronym">TLS</abbr> in application protocols</a>
    <ul class="toc-numbered-mark">
      <li><a id="toc-Separate-ports" href="#Separate-ports">3.7.1 Separate ports</a></li>
      <li><a id="toc-Upward-negotiation" href="#Upward-negotiation">3.7.2 Upward negotiation</a></li>
    </ul></li>
    <li><a id="toc-On-SSL-2-and-older-protocols" href="#On-SSL-2-and-older-protocols">3.8 On SSL 2 and older protocols</a></li>
  </ul></li>
  <li><a id="toc-Authentication-methods" href="#Authentication-methods">4 Authentication methods</a>
  <ul class="toc-numbered-mark">
    <li><a id="toc-Certificate-authentication" href="#Certificate-authentication">4.1 Certificate authentication</a>
    <ul class="toc-numbered-mark">
      <li><a id="toc-X_002e509-certificates" href="#X_002e509-certificates">4.1.1 <abbr class="acronym">X.509</abbr> certificates</a>
      <ul class="toc-numbered-mark">
        <li><a id="toc-X_002e509-certificate-structure" href="#X_002e509-certificate-structure">4.1.1.1 <abbr class="acronym">X.509</abbr> certificate structure</a></li>
        <li><a id="toc-Importing-an-X_002e509-certificate" href="#Importing-an-X_002e509-certificate">4.1.1.2 Importing an X.509 certificate</a></li>
        <li><a id="toc-X_002e509-certificate-names" href="#X_002e509-certificate-names">4.1.1.3 X.509 certificate names</a></li>
        <li><a id="toc-X_002e509-distinguished-names" href="#X_002e509-distinguished-names">4.1.1.4 X.509 distinguished names</a></li>
        <li><a id="toc-X_002e509-extensions" href="#X_002e509-extensions">4.1.1.5 X.509 extensions</a></li>
        <li><a id="toc-Accessing-public-and-private-keys" href="#X_002e509-public-and-private-keys">4.1.1.6 Accessing public and private keys</a></li>
        <li><a id="toc-Verifying-X_002e509-certificate-paths" href="#Verifying-X_002e509-certificate-paths">4.1.1.7 Verifying <abbr class="acronym">X.509</abbr> certificate paths</a></li>
        <li><a id="toc-Verifying-a-certificate-in-the-context-of-TLS-session" href="#Verifying-a-certificate-in-the-context-of-TLS-session">4.1.1.8 Verifying a certificate in the context of TLS session</a></li>
        <li><a id="toc-Verifying-a-certificate-using-PKCS-_002311" href="#Verification-using-PKCS11">4.1.1.9 Verifying a certificate using PKCS #11</a></li>
      </ul></li>
      <li><a id="toc-OpenPGP-certificates" href="#OpenPGP-certificates">4.1.2 <abbr class="acronym">OpenPGP</abbr> certificates</a></li>
      <li><a id="toc-Raw-public_002dkeys" href="#Raw-public_002dkeys">4.1.3 Raw public-keys</a>
      <ul class="toc-numbered-mark">
        <li><a id="toc-Importing-raw-public_002dkeys" href="#Importing-raw-public_002dkeys">4.1.3.1 Importing raw public-keys</a></li>
      </ul></li>
      <li><a id="toc-Advanced-certificate-verification" href="#Advanced-certificate-verification">4.1.4 Advanced certificate verification</a>
      <ul class="toc-numbered-mark">
        <li><a id="toc-Verifying-a-certificate-using-trust-on-first-use-authentication" href="#Verifying-a-certificate-using-trust-on-first-use-authentication">4.1.4.1 Verifying a certificate using trust on first use authentication</a></li>
        <li><a id="toc-Verifying-a-certificate-using-DANE-_0028DNSSEC_0029" href="#Verifying-a-certificate-using-DANE">4.1.4.2 Verifying a certificate using DANE (DNSSEC)</a></li>
      </ul></li>
      <li><a id="toc-Digital-signatures" href="#Digital-signatures">4.1.5 Digital signatures</a>
      <ul class="toc-numbered-mark">
        <li><a id="toc-Trading-security-for-interoperability" href="#Trading-security-for-interoperability">4.1.5.1 Trading security for interoperability</a></li>
      </ul></li>
    </ul></li>
    <li><a id="toc-More-on-certificate-authentication" href="#More-on-certificate-authentication">4.2 More on certificate authentication</a>
    <ul class="toc-numbered-mark">
      <li><a id="toc-PKCS-_002310-certificate-requests" href="#PKCS-10-certificate-requests">4.2.1 <abbr class="acronym">PKCS</abbr> #10 certificate requests</a></li>
      <li><a id="toc-PKIX-certificate-revocation-lists" href="#PKIX-certificate-revocation-lists">4.2.2 PKIX certificate revocation lists</a></li>
      <li><a id="toc-OCSP-certificate-status-checking" href="#OCSP-certificate-status-checking">4.2.3 <abbr class="acronym">OCSP</abbr> certificate status checking</a></li>
      <li><a id="toc-OCSP-stapling" href="#OCSP-stapling">4.2.4 OCSP stapling</a></li>
      <li><a id="toc-Managing-encrypted-keys" href="#Managing-encrypted-keys">4.2.5 Managing encrypted keys</a></li>
      <li><a id="toc-Invoking-certtool" href="#certtool-Invocation">4.2.6 Invoking certtool</a></li>
      <li><a id="toc-Invoking-ocsptool" href="#ocsptool-Invocation">4.2.7 Invoking ocsptool</a></li>
      <li><a id="toc-Invoking-danetool" href="#danetool-Invocation">4.2.8 Invoking danetool</a></li>
    </ul></li>
    <li><a id="toc-Shared_002dkey-and-anonymous-authentication" href="#Shared_002dkey-and-anonymous-authentication">4.3 Shared-key and anonymous authentication</a>
    <ul class="toc-numbered-mark">
      <li><a id="toc-PSK-authentication" href="#PSK-authentication">4.3.1 PSK authentication</a>
      <ul class="toc-numbered-mark">
        <li><a id="toc-Authentication-using-PSK" href="#Authentication-using-PSK">4.3.1.1 Authentication using <abbr class="acronym">PSK</abbr></a></li>
        <li><a id="toc-Invoking-psktool" href="#psktool-Invocation">4.3.1.2 Invoking psktool</a></li>
      </ul></li>
      <li><a id="toc-SRP-authentication" href="#SRP-authentication">4.3.2 SRP authentication</a>
      <ul class="toc-numbered-mark">
        <li><a id="toc-Authentication-using-SRP" href="#Authentication-using-SRP">4.3.2.1 Authentication using <abbr class="acronym">SRP</abbr></a></li>
        <li><a id="toc-Invoking-srptool" href="#srptool-Invocation">4.3.2.2 Invoking srptool</a></li>
      </ul></li>
      <li><a id="toc-Anonymous-authentication" href="#Anonymous-authentication">4.3.3 Anonymous authentication</a></li>
    </ul></li>
    <li><a id="toc-Selecting-an-appropriate-authentication-method" href="#Selecting-an-appropriate-authentication-method">4.4 Selecting an appropriate authentication method</a>
    <ul class="toc-numbered-mark">
      <li><a id="toc-Two-peers-with-an-out_002dof_002dband-channel" href="#Two-peers-with-an-out_002dof_002dband-channel">4.4.1 Two peers with an out-of-band channel</a></li>
      <li><a id="toc-Two-peers-without-an-out_002dof_002dband-channel" href="#Two-peers-without-an-out_002dof_002dband-channel">4.4.2 Two peers without an out-of-band channel</a></li>
      <li><a id="toc-Two-peers-and-a-trusted-third-party" href="#Two-peers-and-a-trusted-third-party">4.4.3 Two peers and a trusted third party</a></li>
    </ul></li>
  </ul></li>
  <li><a id="toc-Abstract-key-types-and-Hardware-security-modules" href="#Hardware-security-modules-and-abstract-key-types">5 Abstract key types and Hardware security modules</a>
  <ul class="toc-numbered-mark">
    <li><a id="toc-Abstract-key-types" href="#Abstract-key-types">5.1 Abstract key types</a>
    <ul class="toc-numbered-mark">
      <li><a id="toc-Public-keys" href="#Abstract-public-keys">5.1.1 Public keys</a></li>
      <li><a id="toc-Private-keys" href="#Abstract-private-keys">5.1.2 Private keys</a></li>
      <li><a id="toc-Operations" href="#Operations">5.1.3 Operations</a></li>
    </ul></li>
    <li><a id="toc-System-and-application_002dspecific-keys" href="#Application_002dspecific-keys">5.2 System and application-specific keys</a>
    <ul class="toc-numbered-mark">
      <li><a id="toc-System_002dspecific-keys" href="#System_002dspecific-keys">5.2.1 System-specific keys</a></li>
      <li><a id="toc-Application_002dspecific-keys" href="#Application_002dspecific-keys-1">5.2.2 Application-specific keys</a></li>
    </ul></li>
    <li><a id="toc-Smart-cards-and-HSMs" href="#Smart-cards-and-HSMs">5.3 Smart cards and HSMs</a>
    <ul class="toc-numbered-mark">
      <li><a id="toc-Initialization" href="#PKCS11-Initialization">5.3.1 Initialization</a></li>
      <li><a id="toc-Manual-initialization-of-user_002dspecific-modules" href="#PKCS11-Manual-Initialization">5.3.2 Manual initialization of user-specific modules</a></li>
      <li><a id="toc-Accessing-objects-that-require-a-PIN" href="#Accessing-objects-that-require-a-PIN">5.3.3 Accessing objects that require a PIN</a></li>
      <li><a id="toc-Reading-objects" href="#Reading-objects">5.3.4 Reading objects</a></li>
      <li><a id="toc-Writing-objects" href="#Writing-objects">5.3.5 Writing objects</a></li>
      <li><a id="toc-Low-Level-Access" href="#PKCS11-Low-Level-Access">5.3.6 Low Level Access</a></li>
      <li><a id="toc-Using-a-PKCS-_002311-token-with-TLS" href="#Using-a-PKCS11-token-with-TLS">5.3.7 Using a <abbr class="acronym">PKCS</abbr> #11 token with TLS</a></li>
      <li><a id="toc-Verifying-certificates-over-PKCS-_002311" href="#Verifying-certificates-over-PKCS11">5.3.8 Verifying certificates over <abbr class="acronym">PKCS</abbr> #11</a></li>
      <li><a id="toc-Invoking-p11tool" href="#p11tool-Invocation">5.3.9 Invoking p11tool</a></li>
    </ul></li>
    <li><a id="toc-Trusted-Platform-Module-_0028TPM_0029" href="#Trusted-Platform-Module">5.4 Trusted Platform Module (TPM)</a>
    <ul class="toc-numbered-mark">
      <li><a id="toc-Keys-in-TPM" href="#Keys-in-TPM">5.4.1 Keys in TPM</a></li>
      <li><a id="toc-Key-generation" href="#Key-generation">5.4.2 Key generation</a></li>
      <li><a id="toc-Using-keys" href="#Using-keys">5.4.3 Using keys</a></li>
      <li><a id="toc-Invoking-tpmtool" href="#tpmtool-Invocation">5.4.4 Invoking tpmtool</a></li>
    </ul></li>
  </ul></li>
  <li><a id="toc-How-to-use-GnuTLS-in-applications" href="#How-to-use-GnuTLS-in-applications">6 How to use <abbr class="acronym">GnuTLS</abbr> in applications</a>
  <ul class="toc-numbered-mark">
    <li><a id="toc-Introduction" href="#Introduction-to-the-library">6.1 Introduction</a>
    <ul class="toc-numbered-mark">
      <li><a id="toc-General-idea" href="#General-idea">6.1.1 General idea</a></li>
      <li><a id="toc-Error-handling" href="#Error-handling">6.1.2 Error handling</a></li>
      <li><a id="toc-Common-types" href="#Common-types">6.1.3 Common types</a></li>
      <li><a id="toc-Debugging-and-auditing" href="#Debugging-and-auditing">6.1.4 Debugging and auditing</a></li>
      <li><a id="toc-Thread-safety" href="#Thread-safety">6.1.5 Thread safety</a></li>
      <li><a id="toc-Running-in-a-sandbox" href="#Running-in-a-sandbox">6.1.6 Running in a sandbox</a></li>
      <li><a id="toc-Sessions-and-fork" href="#Sessions-and-fork">6.1.7 Sessions and fork</a></li>
      <li><a id="toc-Callback-functions" href="#Callback-functions">6.1.8 Callback functions</a></li>
    </ul></li>
    <li><a id="toc-Preparation" href="#Preparation">6.2 Preparation</a>
    <ul class="toc-numbered-mark">
      <li><a id="toc-Headers" href="#Headers">6.2.1 Headers</a></li>
      <li><a id="toc-Initialization-1" href="#Initialization">6.2.2 Initialization</a></li>
      <li><a id="toc-Version-check" href="#Version-check">6.2.3 Version check</a></li>
      <li><a id="toc-Building-the-source" href="#Building-the-source">6.2.4 Building the source</a></li>
    </ul></li>
    <li><a id="toc-Session-initialization" href="#Session-initialization">6.3 Session initialization</a></li>
    <li><a id="toc-Associating-the-credentials" href="#Associating-the-credentials">6.4 Associating the credentials</a>
    <ul class="toc-numbered-mark">
      <li><a id="toc-Certificates" href="#Certificate-credentials">6.4.1 Certificates</a></li>
      <li><a id="toc-Raw-public_002dkeys-1" href="#Raw-public_002dkey-credentials">6.4.2 Raw public-keys</a></li>
      <li><a id="toc-SRP" href="#SRP-credentials">6.4.3 SRP</a></li>
      <li><a id="toc-PSK" href="#PSK-credentials">6.4.4 PSK</a></li>
      <li><a id="toc-Anonymous" href="#Anonymous-credentials">6.4.5 Anonymous</a></li>
    </ul></li>
    <li><a id="toc-Setting-up-the-transport-layer" href="#Setting-up-the-transport-layer">6.5 Setting up the transport layer</a>
    <ul class="toc-numbered-mark">
      <li><a id="toc-Asynchronous-operation" href="#Asynchronous-operation">6.5.1 Asynchronous operation</a>
      <ul class="toc-numbered-mark">
        <li><a id="toc-TLS-protocol" href="#TLS-protocol">6.5.1.1 TLS protocol</a></li>
        <li><a id="toc-Datagram-TLS-protocol" href="#Datagram-TLS-protocol">6.5.1.2 Datagram TLS protocol</a></li>
      </ul></li>
      <li><a id="toc-Reducing-round_002dtrips" href="#Reducing-round_002dtrips">6.5.2 Reducing round-trips</a></li>
      <li><a id="toc-Zero_002droundtrip-mode" href="#Zero_002droundtrip-mode">6.5.3 Zero-roundtrip mode</a></li>
      <li><a id="toc-Anti_002dreplay-protection" href="#Anti_002dreplay-protection">6.5.4 Anti-replay protection</a></li>
      <li><a id="toc-DTLS-sessions" href="#DTLS-sessions">6.5.5 DTLS sessions</a></li>
      <li><a id="toc-DTLS-and-SCTP" href="#DTLS-and-SCTP">6.5.6 DTLS and SCTP</a></li>
    </ul></li>
    <li><a id="toc-TLS-handshake" href="#TLS-handshake">6.6 TLS handshake</a></li>
    <li><a id="toc-Data-transfer-and-termination" href="#Data-transfer-and-termination">6.7 Data transfer and termination</a></li>
    <li><a id="toc-Buffered-data-transfer" href="#Buffered-data-transfer">6.8 Buffered data transfer</a></li>
    <li><a id="toc-Handling-alerts" href="#Handling-alerts">6.9 Handling alerts</a></li>
    <li><a id="toc-Priority-strings" href="#Priority-Strings">6.10 Priority strings</a></li>
    <li><a id="toc-Selecting-cryptographic-key-sizes" href="#Selecting-cryptographic-key-sizes">6.11 Selecting cryptographic key sizes</a></li>
    <li><a id="toc-Advanced-topics" href="#Advanced-topics">6.12 Advanced topics</a>
    <ul class="toc-numbered-mark">
      <li><a id="toc-Virtual-hosts-and-credentials" href="#Virtual-hosts-and-credentials">6.12.1 Virtual hosts and credentials</a></li>
      <li><a id="toc-Session-resumption" href="#Session-resumption">6.12.2 Session resumption</a></li>
      <li><a id="toc-Certificate-verification" href="#Certificate-verification">6.12.3 Certificate verification</a>
      <ul class="toc-numbered-mark">
        <li><a id="toc-Trust-on-first-use" href="#Trust-on-first-use">6.12.3.1 Trust on first use</a></li>
        <li><a id="toc-DANE-verification" href="#DANE-verification">6.12.3.2 DANE verification</a></li>
      </ul></li>
      <li><a id="toc-TLS-1_002e2-re_002dauthentication" href="#TLS-1_002e2-re_002dauthentication">6.12.4 TLS 1.2 re-authentication</a>
      <ul class="toc-numbered-mark">
        <li><a id="toc-Client-side" href="#Client-side">6.12.4.1 Client side</a></li>
        <li><a id="toc-Server-side" href="#Server-side">6.12.4.2 Server side</a></li>
      </ul></li>
      <li><a id="toc-TLS-1_002e3-re_002dauthentication-and-re_002dkey" href="#TLS-1_002e3-re_002dauthentication-and-re_002dkey">6.12.5 TLS 1.3 re-authentication and re-key</a></li>
      <li><a id="toc-Parameter-generation" href="#Parameter-generation">6.12.6 Parameter generation</a>
      <ul class="toc-numbered-mark">
        <li><a id="toc-Legacy-parameter-generation" href="#Legacy-parameter-generation">6.12.6.1 Legacy parameter generation</a></li>
      </ul></li>
      <li><a id="toc-Deriving-keys-for-other-applications_002fprotocols" href="#Deriving-keys-for-other-applications_002fprotocols">6.12.7 Deriving keys for other applications/protocols</a></li>
      <li><a id="toc-Channel-bindings" href="#Channel-Bindings">6.12.8 Channel bindings</a></li>
      <li><a id="toc-Interoperability" href="#Interoperability">6.12.9 Interoperability</a></li>
      <li><a id="toc-Compatibility-with-the-OpenSSL-library" href="#Compatibility-with-the-OpenSSL-library">6.12.10 Compatibility with the OpenSSL library</a></li>
    </ul></li>
  </ul></li>
  <li><a id="toc-GnuTLS-application-examples" href="#GnuTLS-application-examples">7 GnuTLS application examples</a>
  <ul class="toc-numbered-mark">
    <li><a id="toc-Client-examples" href="#Client-examples">7.1 Client examples</a>
    <ul class="toc-numbered-mark">
      <li><a id="toc-Client-example-with-X_002e509-certificate-support" href="#Client-example-with-X_002e509-certificate-support">7.1.1 Client example with <abbr class="acronym">X.509</abbr> certificate support</a></li>
      <li><a id="toc-Datagram-TLS-client-example" href="#Datagram-TLS-client-example">7.1.2 Datagram <abbr class="acronym">TLS</abbr> client example</a></li>
      <li><a id="toc-Using-a-smart-card-with-TLS" href="#Client-using-a-smart-card-with-TLS">7.1.3 Using a smart card with TLS</a></li>
      <li><a id="toc-Client-with-resume-capability-example" href="#Client-with-Resume-capability-example">7.1.4 Client with resume capability example</a></li>
      <li><a id="toc-Client-example-with-SSH_002dstyle-certificate-verification" href="#Client-example-with-SSH_002dstyle-certificate-verification">7.1.5 Client example with SSH-style certificate verification</a></li>
    </ul></li>
    <li><a id="toc-Server-examples" href="#Server-examples">7.2 Server examples</a>
    <ul class="toc-numbered-mark">
      <li><a id="toc-Echo-server-with-X_002e509-authentication" href="#Echo-server-with-X_002e509-authentication">7.2.1 Echo server with <abbr class="acronym">X.509</abbr> authentication</a></li>
      <li><a id="toc-DTLS-echo-server-with-X_002e509-authentication" href="#DTLS-echo-server-with-X_002e509-authentication">7.2.2 DTLS echo server with <abbr class="acronym">X.509</abbr> authentication</a></li>
    </ul></li>
    <li><a id="toc-More-advanced-client-and-servers" href="#More-advanced-client-and-servers">7.3 More advanced client and servers</a>
    <ul class="toc-numbered-mark">
      <li><a id="toc-Client-example-with-anonymous-authentication" href="#Client-example-with-anonymous-authentication">7.3.1 Client example with anonymous authentication</a></li>
      <li><a id="toc-Using-a-callback-to-select-the-certificate-to-use" href="#Using-a-callback-to-select-the-certificate-to-use">7.3.2 Using a callback to select the certificate to use</a></li>
      <li><a id="toc-Obtaining-session-information" href="#Obtaining-session-information">7.3.3 Obtaining session information</a></li>
      <li><a id="toc-Advanced-certificate-verification-1" href="#Advanced-certificate-verification-example">7.3.4 Advanced certificate verification</a></li>
      <li><a id="toc-Client-example-with-PSK-authentication" href="#Client-example-with-PSK-authentication">7.3.5 Client example with <abbr class="acronym">PSK</abbr> authentication</a></li>
      <li><a id="toc-Client-example-with-SRP-authentication" href="#Client-example-with-SRP-authentication">7.3.6 Client example with <abbr class="acronym">SRP</abbr> authentication</a></li>
      <li><a id="toc-Legacy-client-example-with-X_002e509-certificate-support" href="#Legacy-client-example-with-X_002e509-certificate-support">7.3.7 Legacy client example with <abbr class="acronym">X.509</abbr> certificate support</a></li>
      <li><a id="toc-Client-example-using-the-C_002b_002b-API" href="#Client-example-in-C_002b_002b">7.3.8 Client example using the C++ API</a></li>
      <li><a id="toc-Echo-server-with-PSK-authentication" href="#Echo-server-with-PSK-authentication">7.3.9 Echo server with <abbr class="acronym">PSK</abbr> authentication</a></li>
      <li><a id="toc-Echo-server-with-SRP-authentication" href="#Echo-server-with-SRP-authentication">7.3.10 Echo server with <abbr class="acronym">SRP</abbr> authentication</a></li>
      <li><a id="toc-Echo-server-with-anonymous-authentication" href="#Echo-server-with-anonymous-authentication">7.3.11 Echo server with anonymous authentication</a></li>
      <li><a id="toc-Helper-functions-for-TCP-connections" href="#Helper-functions-for-TCP-connections">7.3.12 Helper functions for TCP connections</a></li>
      <li><a id="toc-Helper-functions-for-UDP-connections" href="#Helper-functions-for-UDP-connections">7.3.13 Helper functions for UDP connections</a></li>
    </ul></li>
    <li><a id="toc-OCSP-example" href="#OCSP-example">7.4 OCSP example</a></li>
    <li><a id="toc-Miscellaneous-examples" href="#Miscellaneous-examples">7.5 Miscellaneous examples</a>
    <ul class="toc-numbered-mark">
      <li><a id="toc-Checking-for-an-alert" href="#Checking-for-an-alert">7.5.1 Checking for an alert</a></li>
      <li><a id="toc-X_002e509-certificate-parsing-example" href="#X_002e509-certificate-parsing-example">7.5.2 <abbr class="acronym">X.509</abbr> certificate parsing example</a></li>
      <li><a id="toc-Listing-the-ciphersuites-in-a-priority-string" href="#Listing-the-ciphersuites-in-a-priority-string">7.5.3 Listing the ciphersuites in a priority string</a></li>
      <li><a id="toc-PKCS-_002312-structure-generation-example" href="#PKCS12-structure-generation-example">7.5.4 PKCS #12 structure generation example</a></li>
    </ul></li>
  </ul></li>
  <li><a id="toc-System_002dwide-configuration-of-the-library" href="#System_002dwide-configuration-of-the-library">8 System-wide configuration of the library</a>
  <ul class="toc-numbered-mark">
    <li><a id="toc-Application_002dspecific-priority-strings" href="#Application_002dspecific-priority-strings">8.1 Application-specific priority strings</a></li>
    <li><a id="toc-Disabling-algorithms-and-protocols" href="#Disabling-algorithms-and-protocols">8.2 Disabling algorithms and protocols</a>
    <ul class="toc-numbered-mark">
      <li><a id="toc-Examples" href="#Examples">8.2.1 Examples</a></li>
    </ul></li>
    <li><a id="toc-Querying-for-disabled-algorithms-and-protocols" href="#Querying-for-disabled-algorithms-and-protocols">8.3 Querying for disabled algorithms and protocols</a></li>
    <li><a id="toc-Overriding-the-parameter-verification-profile" href="#Overriding-the-parameter-verification-profile">8.4 Overriding the parameter verification profile</a></li>
    <li><a id="toc-Overriding-the-default-priority-string" href="#Overriding-the-default-priority-string">8.5 Overriding the default priority string</a></li>
    <li><a id="toc-Enabling-TLS-certificate-compression" href="#Enabling-TLS-certificate-compression">8.6 Enabling TLS certificate compression</a></li>
    <li><a id="toc-Enabling_002fDisabling-system_002facceleration-protocols" href="#Enabling_002fDisabling-system_002facceleration-protocols">8.7 Enabling/Disabling system/acceleration protocols</a>
    <ul class="toc-numbered-mark">
      <li><a id="toc-Enabling-kTLS" href="#Enabling-kTLS">8.7.1 Enabling kTLS</a></li>
    </ul></li>
    <li><a id="toc-Enabling_002fDisabling-RSAES_002dPKCS1_002dv1_005f5" href="#Enabling_002fDisabling-RSAES_002dPKCS1_002dv1_005f5">8.8 Enabling/Disabling RSAES-PKCS1-v1_5</a></li>
    <li><a id="toc-Using-PKCS_002311-module-as-cryptographic-backend" href="#Using-PKCS_002311-module-as-cryptographic-backend">8.9 Using PKCS#11 module as cryptographic backend</a>
    <ul class="toc-numbered-mark">
      <li><a id="toc-Examples-1" href="#Examples-1">8.9.1 Examples</a></li>
    </ul></li>
  </ul></li>
  <li><a id="toc-Using-GnuTLS-as-a-cryptographic-library" href="#Using-GnuTLS-as-a-cryptographic-library">9 Using GnuTLS as a cryptographic library</a>
  <ul class="toc-numbered-mark">
    <li><a id="toc-Symmetric-algorithms" href="#Symmetric-algorithms">9.1 Symmetric algorithms</a></li>
    <li><a id="toc-Public-key-algorithms" href="#Public-key-algorithms">9.2 Public key algorithms</a>
    <ul class="toc-numbered-mark">
      <li><a id="toc-Key-generation-1" href="#Key-generation-2">9.2.1 Key generation</a></li>
    </ul></li>
    <li><a id="toc-Cryptographic-Message-Syntax-_002f-PKCS7" href="#Cryptographic-Message-Syntax-_002f-PKCS7">9.3 Cryptographic Message Syntax / PKCS7</a></li>
    <li><a id="toc-Hash-and-MAC-functions" href="#Hash-and-MAC-functions">9.4 Hash and MAC functions</a></li>
    <li><a id="toc-Random-number-generation" href="#Random-number-generation">9.5 Random number generation</a></li>
    <li><a id="toc-Overriding-algorithms" href="#Overriding-algorithms">9.6 Overriding algorithms</a></li>
  </ul></li>
  <li><a id="toc-Other-included-programs" href="#Other-included-programs">10 Other included programs</a></li>
  <li><a id="toc-Internal-Architecture-of-GnuTLS" href="#Internal-architecture-of-GnuTLS">11 Internal Architecture of GnuTLS</a>
  <ul class="toc-numbered-mark">
    <li><a id="toc-The-TLS-Protocol" href="#The-TLS-Protocol">11.1 The TLS Protocol</a></li>
    <li><a id="toc-TLS-Handshake-Protocol" href="#TLS-Handshake-Protocol">11.2 TLS Handshake Protocol</a></li>
    <li><a id="toc-TLS-Authentication-Methods" href="#TLS-Authentication-Methods">11.3 TLS Authentication Methods</a></li>
    <li><a id="toc-TLS-Extension-Handling" href="#TLS-Hello-Extension-Handling">11.4 TLS Extension Handling</a></li>
    <li><a id="toc-Cryptographic-Backend" href="#Cryptographic-Backend">11.5 Cryptographic Backend</a></li>
    <li><a id="toc-Random-Number-Generators" href="#Random-Number-Generators_002dinternals">11.6 Random Number Generators</a></li>
    <li><a id="toc-FIPS140_002d2-mode" href="#FIPS140_002d2-mode">11.7 FIPS140-2 mode</a></li>
  </ul></li>
  <li><a id="toc-Upgrading-from-previous-versions" href="#Upgrading-from-previous-versions">Appendix A Upgrading from previous versions</a></li>
  <li><a id="toc-Support" href="#Support">Appendix B Support</a>
  <ul class="toc-numbered-mark">
    <li><a id="toc-Getting-Help" href="#Getting-help">B.1 Getting Help</a></li>
    <li><a id="toc-Commercial-Support" href="#Commercial-Support">B.2 Commercial Support</a></li>
    <li><a id="toc-Bug-Reports" href="#Bug-Reports">B.3 Bug Reports</a></li>
    <li><a id="toc-Contributing" href="#Contributing">B.4 Contributing</a></li>
    <li><a id="toc-Certification" href="#Certification">B.5 Certification</a></li>
  </ul></li>
  <li><a id="toc-Error-Codes-and-Descriptions" href="#Error-codes">Appendix C Error Codes and Descriptions</a></li>
  <li><a id="toc-Supported-Ciphersuites" href="#Supported-ciphersuites">Appendix D Supported Ciphersuites</a></li>
  <li><a id="toc-API-reference" href="#API-reference">Appendix E API reference</a>
  <ul class="toc-numbered-mark">
    <li><a id="toc-Core-TLS-API" href="#Core-TLS-API">E.1 Core TLS API</a></li>
    <li><a id="toc-Datagram-TLS-API" href="#Datagram-TLS-API">E.2 Datagram TLS API</a></li>
    <li><a id="toc-X_002e509-certificate-API" href="#X509-certificate-API">E.3 <abbr class="acronym">X.509</abbr> certificate API</a></li>
    <li><a id="toc-PKCS-7-API" href="#PKCS-7-API">E.4 <abbr class="acronym">PKCS</abbr> 7 API</a></li>
    <li><a id="toc-OCSP-API" href="#OCSP-API">E.5 <abbr class="acronym">OCSP</abbr> API</a></li>
    <li><a id="toc-PKCS-12-API" href="#PKCS-12-API">E.6 PKCS 12 API</a></li>
    <li><a id="toc-Hardware-token-via-PKCS-11-API" href="#PKCS-11-API">E.7 Hardware token via PKCS 11 API</a></li>
    <li><a id="toc-TPM-API" href="#TPM-API">E.8 TPM API</a></li>
    <li><a id="toc-Abstract-key-API" href="#Abstract-key-API">E.9 Abstract key API</a></li>
    <li><a id="toc-Socket-specific-API" href="#Socket-specific-API">E.10 Socket specific API</a></li>
    <li><a id="toc-DANE-API" href="#DANE-API">E.11 DANE API</a></li>
    <li><a id="toc-Cryptographic-API" href="#Cryptographic-API">E.12 Cryptographic API</a></li>
    <li><a id="toc-Compatibility-API" href="#Compatibility-API">E.13 Compatibility API</a></li>
  </ul></li>
  <li><a id="toc-Copying-Information" href="#Copying-Information">Appendix F Copying Information</a></li>
  <li><a id="toc-Additional-Features" href="#Additional-Features">Appendix G Additional Features</a>
  <ul class="toc-numbered-mark">
    <li><a id="toc-kTLS-_0028Kernel-TLS_0029" href="#kTLS-_0028Kernel-TLS_0029">G.1 kTLS (Kernel TLS)</a></li>
  </ul></li>
  <li><a id="toc-Bibliography" href="#Bibliography">Bibliography</a></li>
  <li><a id="toc-Function-and-Data-Index" href="#Function-and-Data-Index" rel="index">Function and Data Index</a></li>
  <li><a id="toc-Concept-Index" href="#Concept-Index" rel="index">Concept Index</a></li>
</ul>
</div>
</div>
<hr>
<div class="chapter-level-extent" id="Preface">
<div class="nav-panel">
<p>
Next: <a href="#Introduction-to-GnuTLS" accesskey="n" rel="next">Introduction to GnuTLS</a>, Previous: <a href="#Top" accesskey="p" rel="prev">GnuTLS</a>, Up: <a href="#Top" accesskey="u" rel="up">GnuTLS</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h2 class="chapter" id="Preface-1"><span>1 Preface<a class="copiable-link" href="#Preface-1"> &para;</a></span></h2>

<p>This document demonstrates and explains the <abbr class="acronym">GnuTLS</abbr>
library API.  A brief introduction to the protocols and the technology
involved is also included so that an application programmer can
better understand the <abbr class="acronym">GnuTLS</abbr> purpose and actual offerings.
Even if <abbr class="acronym">GnuTLS</abbr> is a typical library software, it operates
over several security and cryptographic protocols which require the
programmer to make careful and correct usage of them. Otherwise it
is likely to only obtain a false sense of security.
The term of security is very broad even if restricted to computer
software, and cannot be confined to a single cryptographic
library.  For that reason, do not consider any program secure just
because it uses <abbr class="acronym">GnuTLS</abbr>; there are several ways to compromise
a program or a communication line and <abbr class="acronym">GnuTLS</abbr> only helps with
some of them.
</p>
<p>Although this document tries to be self contained, basic network
programming and public key infrastructure (PKI) knowledge is assumed 
in most of it. A good introduction to networking can be found 
in [<a class="ref" href="#STEVENS">STEVENS</a>], to public key infrastructure in [<a class="ref" href="#GUTPKI">GUTPKI</a>]
and to security engineering in [<a class="ref" href="#ANDERSON">ANDERSON</a>].
</p>
<p>Updated versions of the <abbr class="acronym">GnuTLS</abbr> software and this document
will be available from <a class="url" href="https://www.gnutls.org/">https://www.gnutls.org/</a>.
</p>
<hr>
</div>
<div class="chapter-level-extent" id="Introduction-to-GnuTLS">
<div class="nav-panel">
<p>
Next: <a href="#Introduction-to-TLS" accesskey="n" rel="next">Introduction to <abbr class="acronym">TLS</abbr> and <abbr class="acronym">DTLS</abbr></a>, Previous: <a href="#Preface" accesskey="p" rel="prev">Preface</a>, Up: <a href="#Top" accesskey="u" rel="up">GnuTLS</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h2 class="chapter" id="Introduction-to-GnuTLS-1"><span>2 Introduction to GnuTLS<a class="copiable-link" href="#Introduction-to-GnuTLS-1"> &para;</a></span></h2>

<p>In brief <abbr class="acronym">GnuTLS</abbr> can be described as a library which offers an API
to access secure communication protocols. These protocols provide
privacy over insecure lines, and were designed to prevent
eavesdropping, tampering, or message forgery.
</p>
<p>Technically <abbr class="acronym">GnuTLS</abbr> is a portable ANSI C based library which
implements the protocols ranging from SSL 3.0 to TLS 1.3 (see <a class="ref" href="#Introduction-to-TLS">Introduction to <abbr class="acronym">TLS</abbr> and <abbr class="acronym">DTLS</abbr></a>, 
for a detailed description of the protocols), accompanied
with the required framework for authentication and public key
infrastructure.  Important features of the <abbr class="acronym">GnuTLS</abbr> library
include:
</p>
<ul class="itemize mark-bullet">
<li>Support for TLS 1.3, TLS 1.2, TLS 1.1, TLS 1.0 and optionally SSL 3.0 protocols.

</li><li>Support for Datagram TLS 1.0 and 1.2.

</li><li>Support for handling and verification of <abbr class="acronym">X.509</abbr> certificates.

</li><li>Support for password authentication using <abbr class="acronym">TLS-SRP</abbr>.

</li><li>Support for keyed authentication using <abbr class="acronym">TLS-PSK</abbr>.

</li><li>Support for TPM, <abbr class="acronym">PKCS</abbr> #11 tokens and smart-cards.

</li></ul>

<p>The <abbr class="acronym">GnuTLS</abbr> library consists of three independent parts, namely the &ldquo;TLS
protocol part&rdquo;, the &ldquo;Certificate part&rdquo;, and the &ldquo;Cryptographic
back-end&rdquo; part.  The &ldquo;TLS protocol part&rdquo; is the actual protocol
implementation, and is entirely implemented within the
<abbr class="acronym">GnuTLS</abbr> library.  The &ldquo;Certificate part&rdquo; consists of the
certificate parsing, and verification functions and it uses
functionality from the
libtasn1 library.
The &ldquo;Cryptographic back-end&rdquo; is provided by the nettle
and gmplib libraries.
</p>

<ul class="mini-toc">
<li><a href="#Downloading-and-installing" accesskey="1">Downloading and installing</a></li>
<li><a href="#Installing-for-a-software-distribution" accesskey="2">Installing for a software distribution</a></li>
<li><a href="#Document-overview" accesskey="3">Overview</a></li>
</ul>
<hr>
<div class="section-level-extent" id="Downloading-and-installing">
<div class="nav-panel">
<p>
Next: <a href="#Installing-for-a-software-distribution" accesskey="n" rel="next">Installing for a software distribution</a>, Up: <a href="#Introduction-to-GnuTLS" accesskey="u" rel="up">Introduction to GnuTLS</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Downloading-and-installing-1"><span>2.1 Downloading and installing<a class="copiable-link" href="#Downloading-and-installing-1"> &para;</a></span></h3>
<a class="index-entry-id" id="index-installation"></a>
<a class="index-entry-id" id="index-download"></a>

<p>GnuTLS is available for download at:
<a class="url" href="https://www.gnutls.org/download.html">https://www.gnutls.org/download.html</a>
</p>
<p>GnuTLS uses a development cycle where even minor version numbers
indicate a stable release and a odd minor version number indicate a
development release.  For example, GnuTLS 1.6.3 denote a stable
release since 6 is even, and GnuTLS 1.7.11 denote a development
release since 7 is odd.
</p>
<p>GnuTLS depends on <code class="code">nettle</code> and <code class="code">gmplib</code>, and you will need to install it
before installing GnuTLS.  The <code class="code">nettle</code> library is available from
<a class="url" href="https://www.lysator.liu.se/~nisse/nettle/">https://www.lysator.liu.se/~nisse/nettle/</a>, while <code class="code">gmplib</code> is available
from <a class="url" href="https://www.gmplib.org/">https://www.gmplib.org/</a>.
Don&rsquo;t forget to verify the cryptographic signature after downloading
source code packages.
</p>
<p>The package is then extracted, configured and built like many other
packages that use Autoconf.  For detailed information on configuring
and building it, refer to the <samp class="file">INSTALL</samp> file that is part of the
distribution archive.  Typically you invoke <code class="code">./configure</code> and
then <code class="code">make check install</code>.  There are a number of compile-time
parameters, as discussed below.
</p>
<p>Several parts of GnuTLS require ASN.1 functionality, which is provided by 
a library called libtasn1.  A copy of libtasn1 is included in GnuTLS.  If you
want to install it separately (e.g., to make it possibly to use
libtasn1 in other programs), you can get it from
<a class="url" href="https://www.gnu.org/software/libtasn1/">https://www.gnu.org/software/libtasn1/</a>.
</p>
<p>The compression library, <code class="code">libz</code>, the PKCS #11 helper library <code class="code">p11-kit</code>,
the TPM library <code class="code">trousers</code>, as well as the IDN library <code class="code">libidn</code><a class="footnote" id="DOCF1" href="#FOOT1"><sup>1</sup></a> are 
optional dependencies. Check the README file in the distribution on how
to obtain these libraries.
</p>
<p>A few <code class="code">configure</code> options may be relevant, summarized below.
They disable or enable particular features,
to create a smaller library with only the required features.
Note however, that although a smaller library is generated, the
included programs are not guaranteed to compile if some of these
options are given.
</p>
<pre class="verbatim">--disable-srp-authentication
--disable-psk-authentication
--disable-anon-authentication
--disable-dhe
--disable-ecdhe
--disable-openssl-compatibility
--disable-dtls-srtp-support
--disable-alpn-support
--disable-heartbeat-support
--disable-libdane
--without-p11-kit
--without-tpm
--without-zlib

</pre>
<p>For the complete list, refer to the output from <code class="code">configure --help</code>.
</p>
<hr>
</div>
<div class="section-level-extent" id="Installing-for-a-software-distribution">
<div class="nav-panel">
<p>
Next: <a href="#Document-overview" accesskey="n" rel="next">Overview</a>, Previous: <a href="#Downloading-and-installing" accesskey="p" rel="prev">Downloading and installing</a>, Up: <a href="#Introduction-to-GnuTLS" accesskey="u" rel="up">Introduction to GnuTLS</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Installing-for-a-software-distribution-1"><span>2.2 Installing for a software distribution<a class="copiable-link" href="#Installing-for-a-software-distribution-1"> &para;</a></span></h3>
<a class="index-entry-id" id="index-installation-1"></a>

<p>When installing for a software distribution, it is often desirable to preconfigure
GnuTLS with the system-wide paths and files. There two important configuration
options, one sets the trust store in system, which are the CA certificates
to be used by programs by default (if they don&rsquo;t override it), and the other sets
to DNSSEC root key file used by unbound for DNSSEC verification.
</p>
<p>For the latter the following configuration option is available, and if not specified
GnuTLS will try to auto-detect the location of that file.
</p><pre class="verbatim">--with-unbound-root-key-file

</pre>
<p>To set the trust store the following options are available.
</p><pre class="verbatim">--with-default-trust-store-file
--with-default-trust-store-dir
--with-default-trust-store-pkcs11

</pre><p>The first option is used to set a PEM file which contains a list of trusted certificates,
while the second will read all certificates in the given path. The recommended option is
the last, which allows to use a PKCS #11 trust policy module. That module not only
provides the trusted certificates, but allows the categorization of them using purpose,
e.g., CAs can be restricted for e-mail usage only, or administrative restrictions of CAs, for
examples by restricting a CA to only issue certificates for a given DNS domain using NameConstraints.
A publicly available PKCS #11 trust module is p11-kit&rsquo;s trust module<a class="footnote" id="DOCF2" href="#FOOT2"><sup>2</sup></a>.
</p>
<hr>
</div>
<div class="section-level-extent" id="Document-overview">
<div class="nav-panel">
<p>
Previous: <a href="#Installing-for-a-software-distribution" accesskey="p" rel="prev">Installing for a software distribution</a>, Up: <a href="#Introduction-to-GnuTLS" accesskey="u" rel="up">Introduction to GnuTLS</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Overview"><span>2.3 Overview<a class="copiable-link" href="#Overview"> &para;</a></span></h3>
<p>In this document we present an overview of the supported security protocols in <a class="ref" href="#Introduction-to-TLS">Introduction to <abbr class="acronym">TLS</abbr> and <abbr class="acronym">DTLS</abbr></a>, and 
continue by providing more information on the certificate authentication in <a class="ref" href="#Certificate-authentication">Certificate authentication</a>,
and shared-key as well anonymous authentication in <a class="ref" href="#Shared_002dkey-and-anonymous-authentication">Shared-key and anonymous authentication</a>. We
elaborate on certificate authentication by demonstrating advanced usage of the API in <a class="ref" href="#More-on-certificate-authentication">More on certificate authentication</a>.
The core of the TLS library is presented in <a class="ref" href="#How-to-use-GnuTLS-in-applications">How to use <abbr class="acronym">GnuTLS</abbr> in applications</a> and example
applications are listed in <a class="ref" href="#GnuTLS-application-examples">GnuTLS application examples</a>.
In <a class="ref" href="#Other-included-programs">Other included programs</a> the usage of few included programs that
may assist debugging is presented. The last chapter is <a class="ref" href="#Internal-architecture-of-GnuTLS">Internal Architecture of GnuTLS</a> that
provides a short introduction to GnuTLS&rsquo; internal architecture.
</p>
<hr>
</div>
</div>
<div class="chapter-level-extent" id="Introduction-to-TLS">
<div class="nav-panel">
<p>
Next: <a href="#Authentication-methods" accesskey="n" rel="next">Authentication methods</a>, Previous: <a href="#Introduction-to-GnuTLS" accesskey="p" rel="prev">Introduction to GnuTLS</a>, Up: <a href="#Top" accesskey="u" rel="up">GnuTLS</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h2 class="chapter" id="Introduction-to-TLS-and-DTLS"><span>3 Introduction to <abbr class="acronym">TLS</abbr> and <abbr class="acronym">DTLS</abbr><a class="copiable-link" href="#Introduction-to-TLS-and-DTLS"> &para;</a></span></h2>

<p><abbr class="acronym">TLS</abbr> stands for &ldquo;Transport Layer Security&rdquo; and is the
successor of SSL, the Secure Sockets Layer protocol [<a class="ref" href="#SSL3">SSL3</a>]
designed by Netscape.  <abbr class="acronym">TLS</abbr> is an Internet protocol, defined
by <abbr class="acronym">IETF</abbr><a class="footnote" id="DOCF3" href="#FOOT3"><sup>3</sup></a>, described in [<a class="ref" href="#RFC5246">RFC5246</a>].
The protocol provides
confidentiality, and authentication layers over any reliable transport
layer.  The description, above, refers to <abbr class="acronym">TLS</abbr> 1.0 but applies
to all other TLS versions as the differences between the protocols are not major.
</p>
<p>The <abbr class="acronym">DTLS</abbr> protocol, or &ldquo;Datagram <abbr class="acronym">TLS</abbr>&rdquo; [<a class="ref" href="#RFC4347">RFC4347</a>] is a
protocol with identical goals as <abbr class="acronym">TLS</abbr>, but can operate
under unreliable transport layers such as <abbr class="acronym">UDP</abbr>. The
discussions below apply to this protocol as well, except when
noted otherwise.
</p>

<ul class="mini-toc">
<li><a href="#TLS-layers" accesskey="1">TLS Layers</a></li>
<li><a href="#The-transport-layer" accesskey="2">The Transport Layer</a></li>
<li><a href="#The-TLS-record-protocol" accesskey="3">The TLS record protocol</a></li>
<li><a href="#The-TLS-Alert-Protocol" accesskey="4">The TLS alert protocol</a></li>
<li><a href="#The-TLS-Handshake-Protocol" accesskey="5">The TLS handshake protocol</a></li>
<li><a href="#TLS-Extensions" accesskey="6">TLS extensions</a></li>
<li><a href="#How-to-use-TLS-in-application-protocols" accesskey="7">How to use <abbr class="acronym">TLS</abbr> in application protocols</a></li>
<li><a href="#On-SSL-2-and-older-protocols" accesskey="8">On SSL 2 and older protocols</a></li>
</ul>
<hr>
<div class="section-level-extent" id="TLS-layers">
<div class="nav-panel">
<p>
Next: <a href="#The-transport-layer" accesskey="n" rel="next">The Transport Layer</a>, Up: <a href="#Introduction-to-TLS" accesskey="u" rel="up">Introduction to <abbr class="acronym">TLS</abbr> and <abbr class="acronym">DTLS</abbr></a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="TLS-Layers"><span>3.1 TLS Layers<a class="copiable-link" href="#TLS-Layers"> &para;</a></span></h3>
<a class="index-entry-id" id="index-TLS-layers"></a>

<p><abbr class="acronym">TLS</abbr> is a layered protocol, and consists of the record
protocol, the handshake protocol and the alert protocol. The record
protocol is to serve all other protocols and is above the transport
layer.  The record protocol offers symmetric encryption, and data
authenticity<a class="footnote" id="DOCF4" href="#FOOT4"><sup>4</sup></a>.
The alert protocol offers some signaling to the other protocols. It
can help informing the peer for the cause of failures and other error
conditions.  See <a class="xref" href="#The-Alert-Protocol">The Alert Protocol</a>, for more information.  The
alert protocol is above the record protocol.
</p>
<p>The handshake protocol is responsible for the security parameters&rsquo;
negotiation, the initial key exchange and authentication.
See <a class="xref" href="#The-Handshake-Protocol">The Handshake Protocol</a>, for more information about the handshake
protocol.  The protocol layering in TLS is shown in <a class="ref" href="#fig_002dtls_002dlayers">Figure 3.1</a>.
</p>
<div class="float" id="fig_002dtls_002dlayers">
<img class="image" src="gnutls-layers.png" alt="gnutls-layers">
<div class="caption"><p><strong class="strong">Figure 3.1: </strong>The TLS protocol layers.</p></div></div>
<hr>
</div>
<div class="section-level-extent" id="The-transport-layer">
<div class="nav-panel">
<p>
Next: <a href="#The-TLS-record-protocol" accesskey="n" rel="next">The TLS record protocol</a>, Previous: <a href="#TLS-layers" accesskey="p" rel="prev">TLS Layers</a>, Up: <a href="#Introduction-to-TLS" accesskey="u" rel="up">Introduction to <abbr class="acronym">TLS</abbr> and <abbr class="acronym">DTLS</abbr></a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="The-Transport-Layer"><span>3.2 The Transport Layer<a class="copiable-link" href="#The-Transport-Layer"> &para;</a></span></h3>
<a class="index-entry-id" id="index-transport-protocol"></a>
<a class="index-entry-id" id="index-transport-layer"></a>

<p><abbr class="acronym">TLS</abbr> is not limited to any transport layer and can be used
above any transport layer, as long as it is a reliable one.  <abbr class="acronym">DTLS</abbr>
can be used over reliable and unreliable transport layers.
<abbr class="acronym">GnuTLS</abbr> supports TCP and UDP layers transparently using
the Berkeley sockets API. However, any transport layer can be used
by providing callbacks for <abbr class="acronym">GnuTLS</abbr> to access the transport layer
(for details see <a class="ref" href="#Setting-up-the-transport-layer">Setting up the transport layer</a>).
</p>
<hr>
</div>
<div class="section-level-extent" id="The-TLS-record-protocol">
<div class="nav-panel">
<p>
Next: <a href="#The-TLS-Alert-Protocol" accesskey="n" rel="next">The TLS alert protocol</a>, Previous: <a href="#The-transport-layer" accesskey="p" rel="prev">The Transport Layer</a>, Up: <a href="#Introduction-to-TLS" accesskey="u" rel="up">Introduction to <abbr class="acronym">TLS</abbr> and <abbr class="acronym">DTLS</abbr></a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="The-TLS-record-protocol-1"><span>3.3 The TLS record protocol<a class="copiable-link" href="#The-TLS-record-protocol-1"> &para;</a></span></h3>
<a class="index-entry-id" id="index-record-protocol"></a>

<p>The record protocol is the secure communications provider. Its purpose
is to encrypt, and authenticate packets.
The record layer functions can be called at any time after
the handshake process is finished, when there is need to receive
or send data. In <abbr class="acronym">DTLS</abbr> however, due to re-transmission
timers used in the handshake out-of-order handshake data might
be received for some time (maximum 60 seconds) after the handshake
process is finished.
</p>
<p>The functions to access the record protocol are limited to send
and receive functions, which might, given
the importance of this protocol in <abbr class="acronym">TLS</abbr>, seem awkward.  This is because
the record protocol&rsquo;s parameters are all set by the handshake protocol.
The record protocol initially starts with NULL parameters, which means
no encryption, and no MAC is used. Encryption and authentication begin
just after the handshake protocol has finished.
</p>

<ul class="mini-toc">
<li><a href="#Encryption-algorithms-used-in-the-record-layer" accesskey="1">Encryption algorithms used in the record layer</a></li>
<li><a href="#Compression-algorithms-and-the-record-layer" accesskey="2">Compression algorithms and the record layer</a></li>
<li><a href="#On-Record-Padding" accesskey="3">On record padding</a></li>
</ul>
<hr>
<div class="subsection-level-extent" id="Encryption-algorithms-used-in-the-record-layer">
<div class="nav-panel">
<p>
Next: <a href="#Compression-algorithms-and-the-record-layer" accesskey="n" rel="next">Compression algorithms and the record layer</a>, Up: <a href="#The-TLS-record-protocol" accesskey="u" rel="up">The TLS record protocol</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Encryption-algorithms-used-in-the-record-layer-1"><span>3.3.1 Encryption algorithms used in the record layer<a class="copiable-link" href="#Encryption-algorithms-used-in-the-record-layer-1"> &para;</a></span></h4>
<a class="index-entry-id" id="index-symmetric-encryption-algorithms"></a>

<p>Confidentiality in the record layer is achieved by using symmetric
ciphers like <code class="code">AES</code> or <code class="code">CHACHA20</code>.  Ciphers are encryption algorithms
that use a single, secret, key to encrypt and decrypt data. Early
versions of TLS separated between block and stream ciphers and had
message authentication plugged in to them by the protocol, though later
versions switched to using authenticated-encryption (AEAD) ciphers. The AEAD
ciphers are defined to combine encryption and authentication, and as such
they are not only more efficient, as the primitives used are designed to
interoperate nicely, but they are also known to interoperate in a secure
way.
</p>
<p>The supported in <abbr class="acronym">GnuTLS</abbr> ciphers and MAC algorithms are shown in <a class="ref" href="#tab_003aciphers">Table 3.1</a> and
<a class="ref" href="#tab_003amacs">Table 3.2</a>.
</p>
<div class="float" id="tab_003aciphers">
<table class="multitable">
<thead><tr><th width="20%">Algorithm</th><th width="10%">Type</th><th width="15%">Applicable Protocols</th><th width="55%">Description</th></tr></thead>
<tbody><tr><td width="20%">AES-128-GCM, AES-256-GCM</td><td width="10%">AEAD</td><td width="15%">TLS 1.2, TLS 1.3</td><td width="55%">This is the AES algorithm in the authenticated encryption GCM mode.
This mode combines message authentication and encryption and can
be extremely fast on CPUs that support hardware acceleration.</td></tr>
<tr><td width="20%">AES-128-CCM, AES-256-CCM</td><td width="10%">AEAD</td><td width="15%">TLS 1.2, TLS 1.3</td><td width="55%">This is the AES algorithm in the authenticated encryption CCM mode.
This mode combines message authentication and encryption and is
often used by systems without AES or GCM acceleration support.</td></tr>
<tr><td width="20%">CHACHA20-POLY1305</td><td width="10%">AEAD</td><td width="15%">TLS 1.2, TLS 1.3</td><td width="55%">CHACHA20-POLY1305 is an authenticated encryption algorithm based on CHACHA20 cipher and
POLY1305 MAC. CHACHA20 is a refinement of SALSA20 algorithm, an approved cipher by
the European ESTREAM project. POLY1305 is Wegman-Carter, one-time authenticator. The
combination provides a fast stream cipher suitable for systems where a hardware AES
accelerator is not available.</td></tr>
<tr><td width="20%">AES-128-CCM-8, AES-256-CCM-8</td><td width="10%">AEAD</td><td width="15%">TLS 1.2, TLS 1.3</td><td width="55%">This is the AES algorithm in the authenticated encryption CCM mode
with a truncated to 64-bit authentication tag. This mode is for
communication with restricted systems.</td></tr>
<tr><td width="20%">CAMELLIA-128-GCM, CAMELLIA-256-GCM</td><td width="10%">AEAD</td><td width="15%">TLS 1.2</td><td width="55%">This is the CAMELLIA algorithm in the authenticated encryption GCM mode.</td></tr>
<tr><td width="20%">AES-128-CBC, AES-256-CBC</td><td width="10%">Legacy (block)</td><td width="15%">TLS 1.0, TLS 1.1, TLS 1.2</td><td width="55%">AES or RIJNDAEL is the block cipher algorithm that replaces the old
DES algorithm.  It has 128 bits block size and is used in CBC mode.</td></tr>
<tr><td width="20%">CAMELLIA-128-CBC, CAMELLIA-256-CBC</td><td width="10%">Legacy (block)</td><td width="15%">TLS 1.0, TLS 1.1, TLS 1.2</td><td width="55%">This is an 128-bit block cipher developed by Mitsubishi and NTT. It
is one of the approved ciphers of the European NESSIE and Japanese
CRYPTREC projects.</td></tr>
<tr><td width="20%">3DES-CBC</td><td width="10%">Legacy (block)</td><td width="15%">TLS 1.0, TLS 1.1, TLS 1.2</td><td width="55%">This is the DES block cipher algorithm used with triple
encryption (EDE). Has 64 bits block size and is used in CBC mode.</td></tr>
<tr><td width="20%">ARCFOUR-128</td><td width="10%">Legacy (stream)</td><td width="15%">TLS 1.0, TLS 1.1, TLS 1.2</td><td width="55%">ARCFOUR-128 is a compatible algorithm with RSA&rsquo;s RC4 algorithm, which is considered to be a trade
secret. It is a considered to be broken, and is only used for compatibility
purposed. For this reason it is not enabled by default.</td></tr>
<tr><td width="20%">GOST28147-TC26Z-CNT</td><td width="10%">Legacy (stream)</td><td width="15%">TLS 1.2</td><td width="55%">This is a 64-bit block cipher GOST 28147-89 with TC26Z S-Box working in CNT
mode. It is one of the approved ciphers in Russia. It is not enabled by default.</td></tr>
<tr><td width="20%">NULL</td><td width="10%">Legacy (stream)</td><td width="15%">TLS 1.0, TLS 1.1, TLS 1.2</td><td width="55%">NULL is the empty/identity cipher which doesn&rsquo;t encrypt any data. It can be
combined with data authentication under TLS 1.2 or earlier, but is only used
transiently under TLS 1.3 until encryption starts. This cipher cannot be negotiated
by default (need to be explicitly enabled) under TLS 1.2, and cannot be
negotiated at all under TLS 1.3. When enabled, TLS 1.3 (or later) support will be
implicitly disabled.</td></tr>
</tbody>
</table>
<div class="caption"><p><strong class="strong">Table 3.1: </strong>Supported ciphers in TLS.</p></div></div>

<div class="float" id="tab_003amacs">
<table class="multitable">
<thead><tr><th width="20%">Algorithm</th><th width="70%">Description</th></tr></thead>
<tbody><tr><td width="20%">MAC-MD5</td><td width="70%">This is an HMAC based on MD5 a cryptographic hash algorithm designed
by Ron Rivest. Outputs 128 bits of data.</td></tr>
<tr><td width="20%">MAC-SHA1</td><td width="70%">An HMAC based on the SHA1 cryptographic hash algorithm
designed by NSA. Outputs 160 bits of data.</td></tr>
<tr><td width="20%">MAC-SHA256</td><td width="70%">An HMAC based on SHA2-256. Outputs 256 bits of data.</td></tr>
<tr><td width="20%">MAC-SHA384</td><td width="70%">An HMAC based on SHA2-384. Outputs 384 bits of data.</td></tr>
<tr><td width="20%">GOST28147-TC26Z-IMIT</td><td width="70%">This is a 64-bit block cipher GOST 28147-89 with TC26Z S-Box working in special
MAC mode called Imitovstavks. It is one of the approved MAC algorithms in
Russia. Outputs 32 bits of data. It is not enabled by default.</td></tr>
<tr><td width="20%">MAC-AEAD</td><td width="70%">This indicates that an authenticated encryption algorithm, such as
GCM, is in use.</td></tr>
</tbody>
</table>
<div class="caption"><p><strong class="strong">Table 3.2: </strong>Supported MAC algorithms in TLS.</p></div></div>

<hr>
</div>
<div class="subsection-level-extent" id="Compression-algorithms-and-the-record-layer">
<div class="nav-panel">
<p>
Next: <a href="#On-Record-Padding" accesskey="n" rel="next">On record padding</a>, Previous: <a href="#Encryption-algorithms-used-in-the-record-layer" accesskey="p" rel="prev">Encryption algorithms used in the record layer</a>, Up: <a href="#The-TLS-record-protocol" accesskey="u" rel="up">The TLS record protocol</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Compression-algorithms-and-the-record-layer-1"><span>3.3.2 Compression algorithms and the record layer<a class="copiable-link" href="#Compression-algorithms-and-the-record-layer-1"> &para;</a></span></h4>
<a class="index-entry-id" id="index-compression-algorithms"></a>

<p>In early versions of TLS the record layer supported compression. However,
that proved to be problematic in many ways, and enabled several attacks
based on traffic analysis on the transported data. For that newer versions of the protocol no longer
offer compression, and <abbr class="acronym">GnuTLS</abbr> since 3.6.0 no longer implements any
support for compression.
</p>
<hr>
</div>
<div class="subsection-level-extent" id="On-Record-Padding">
<div class="nav-panel">
<p>
Previous: <a href="#Compression-algorithms-and-the-record-layer" accesskey="p" rel="prev">Compression algorithms and the record layer</a>, Up: <a href="#The-TLS-record-protocol" accesskey="u" rel="up">The TLS record protocol</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="On-record-padding"><span>3.3.3 On record padding<a class="copiable-link" href="#On-record-padding"> &para;</a></span></h4>
<a class="index-entry-id" id="index-record-padding"></a>
<a class="index-entry-id" id="index-bad_005frecord_005fmac"></a>

<p>The TLS 1.3 protocol allows for extra padding of records to prevent
statistical analysis based on the length of exchanged messages.
GnuTLS takes advantage of this feature, by allowing the user
to specify the amount of padding for a particular message. The simplest
interface is provided by <a class="ref" href="#gnutls_005frecord_005fsend2">gnutls_record_send2</a>, and is made
available when under TLS1.3; alternatively <a class="ref" href="#gnutls_005frecord_005fcan_005fuse_005flength_005fhiding">gnutls_record_can_use_length_hiding</a>
can be queried.
</p>
<p>Note that this interface is not sufficient to completely hide the length of the
data. The application code may reveal the data transferred by leaking its
data processing time, or by leaking the TLS1.3 record processing time by
GnuTLS. That is because under TLS1.3 the padding removal time depends on the
padding data for an efficient implementation. To make that processing
constant time the <a class="ref" href="#gnutls_005finit">gnutls_init</a> function must be called with
the flag <code class="code">GNUTLS_SAFE_PADDING_CHECK</code>.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frecord_005fsend2"><span class="category-def">Function: </span><span><code class="def-type">ssize_t</code> <strong class="def-name">gnutls_record_send2</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, const void * <var class="var">data</var>, size_t <var class="var">data_size</var>, size_t <var class="var">pad</var>, unsigned <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005frecord_005fsend2"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">data</var>: contains the data to send
</p>
<p><var class="var">data_size</var>: is the length of the data
</p>
<p><var class="var">pad</var>: padding to be added to the record
</p>
<p><var class="var">flags</var>: must be zero
</p>
<p>This function is identical to <code class="code">gnutls_record_send()</code>  except that it
takes an extra argument to specify padding to be added the record.
To determine the maximum size of padding, use
<code class="code">gnutls_record_get_max_size()</code>  and <code class="code">gnutls_record_overhead_size()</code> .
</p>
<p>Note that in order for GnuTLS to provide constant time processing
of padding and data in TLS1.3, the flag <code class="code">GNUTLS_SAFE_PADDING_CHECK</code> 
must be used in <code class="code">gnutls_init()</code> .
</p>
<p><strong class="strong">Returns:</strong> The number of bytes sent, or a negative error code.  The
number of bytes sent might be less than  <code class="code">data_size</code> .  The maximum
number of bytes this function can send in a single call depends
on the negotiated maximum record size.
</p>
<p><strong class="strong">Since:</strong> 3.6.3
</p></dd></dl>

<p>Older GnuTLS versions provided an API suitable for cases where the sender
sends data that are always within a given range. That API is still
available, and consists of the following functions.
</p>
<dl class="table">
<dt><code class="code"><var class="var">unsigned</var> <a class="ref" href="#gnutls_005frecord_005fcan_005fuse_005flength_005fhiding">gnutls_record_can_use_length_hiding</a> (gnutls_session_t <var class="var">session</var>)</code></dt>
<dt><code class="code"><var class="var">ssize_t</var> <a class="ref" href="#gnutls_005frecord_005fsend_005frange">gnutls_record_send_range</a> (gnutls_session_t <var class="var">session</var>, const void * <var class="var">data</var>, size_t <var class="var">data_size</var>, const gnutls_range_st * <var class="var">range</var>)</code></dt>
</dl>

<hr>
</div>
</div>
<div class="section-level-extent" id="The-TLS-Alert-Protocol">
<div class="nav-panel">
<p>
Next: <a href="#The-TLS-Handshake-Protocol" accesskey="n" rel="next">The TLS handshake protocol</a>, Previous: <a href="#The-TLS-record-protocol" accesskey="p" rel="prev">The TLS record protocol</a>, Up: <a href="#Introduction-to-TLS" accesskey="u" rel="up">Introduction to <abbr class="acronym">TLS</abbr> and <abbr class="acronym">DTLS</abbr></a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="The-TLS-alert-protocol"><span>3.4 The TLS alert protocol<a class="copiable-link" href="#The-TLS-alert-protocol"> &para;</a></span></h3>
<a class="anchor" id="The-Alert-Protocol"></a><a class="index-entry-id" id="index-alert-protocol"></a>

<p>The alert protocol is there to allow signals to be sent between peers.
These signals are mostly used to inform the peer about the cause of a
protocol failure. Some of these signals are used internally by the
protocol and the application protocol does not have to cope with them
(e.g. <code class="code">GNUTLS_A_CLOSE_NOTIFY</code>), and others refer to the
application protocol solely (e.g. <code class="code">GNUTLS_A_USER_CANCELLED</code>).  An
alert signal includes a level indication which may be either fatal or
warning (under TLS1.3 all alerts are fatal). Fatal alerts always terminate
the current connection, and prevent future re-negotiations using the current
session ID. All supported alert messages are summarized in the table below.
</p>
<p>The alert messages are protected by the record protocol, thus the
information that is included does not leak. You must take extreme care
for the alert information not to leak to a possible attacker, via
public log files etc.
</p>
<table class="multitable">
<tr><td><a class="anchor" id="tab_003aalerts"></a></td></tr>
<thead><tr><th width="55%">Alert</th><th width="10%">ID</th><th width="30%">Description</th></tr></thead>
<tbody><tr><td width="55%">GNUTLS_A_CLOSE_NOTIFY</td><td width="10%">0</td><td width="30%">Close notify</td></tr>
<tr><td width="55%">GNUTLS_A_UNEXPECTED_MESSAGE</td><td width="10%">10</td><td width="30%">Unexpected message</td></tr>
<tr><td width="55%">GNUTLS_A_BAD_RECORD_MAC</td><td width="10%">20</td><td width="30%">Bad record MAC</td></tr>
<tr><td width="55%">GNUTLS_A_DECRYPTION_FAILED</td><td width="10%">21</td><td width="30%">Decryption failed</td></tr>
<tr><td width="55%">GNUTLS_A_RECORD_OVERFLOW</td><td width="10%">22</td><td width="30%">Record overflow</td></tr>
<tr><td width="55%">GNUTLS_A_DECOMPRESSION_FAILURE</td><td width="10%">30</td><td width="30%">Decompression failed</td></tr>
<tr><td width="55%">GNUTLS_A_HANDSHAKE_FAILURE</td><td width="10%">40</td><td width="30%">Handshake failed</td></tr>
<tr><td width="55%">GNUTLS_A_SSL3_NO_CERTIFICATE</td><td width="10%">41</td><td width="30%">No certificate (SSL 3.0)</td></tr>
<tr><td width="55%">GNUTLS_A_BAD_CERTIFICATE</td><td width="10%">42</td><td width="30%">Certificate is bad</td></tr>
<tr><td width="55%">GNUTLS_A_UNSUPPORTED_CERTIFICATE</td><td width="10%">43</td><td width="30%">Certificate is not supported</td></tr>
<tr><td width="55%">GNUTLS_A_CERTIFICATE_REVOKED</td><td width="10%">44</td><td width="30%">Certificate was revoked</td></tr>
<tr><td width="55%">GNUTLS_A_CERTIFICATE_EXPIRED</td><td width="10%">45</td><td width="30%">Certificate is expired</td></tr>
<tr><td width="55%">GNUTLS_A_CERTIFICATE_UNKNOWN</td><td width="10%">46</td><td width="30%">Unknown certificate</td></tr>
<tr><td width="55%">GNUTLS_A_ILLEGAL_PARAMETER</td><td width="10%">47</td><td width="30%">Illegal parameter</td></tr>
<tr><td width="55%">GNUTLS_A_UNKNOWN_CA</td><td width="10%">48</td><td width="30%">CA is unknown</td></tr>
<tr><td width="55%">GNUTLS_A_ACCESS_DENIED</td><td width="10%">49</td><td width="30%">Access was denied</td></tr>
<tr><td width="55%">GNUTLS_A_DECODE_ERROR</td><td width="10%">50</td><td width="30%">Decode error</td></tr>
<tr><td width="55%">GNUTLS_A_DECRYPT_ERROR</td><td width="10%">51</td><td width="30%">Decrypt error</td></tr>
<tr><td width="55%">GNUTLS_A_EXPORT_RESTRICTION</td><td width="10%">60</td><td width="30%">Export restriction</td></tr>
<tr><td width="55%">GNUTLS_A_PROTOCOL_VERSION</td><td width="10%">70</td><td width="30%">Error in protocol version</td></tr>
<tr><td width="55%">GNUTLS_A_INSUFFICIENT_SECURITY</td><td width="10%">71</td><td width="30%">Insufficient security</td></tr>
<tr><td width="55%">GNUTLS_A_INTERNAL_ERROR</td><td width="10%">80</td><td width="30%">Internal error</td></tr>
<tr><td width="55%">GNUTLS_A_INAPPROPRIATE_FALLBACK</td><td width="10%">86</td><td width="30%">Inappropriate fallback</td></tr>
<tr><td width="55%">GNUTLS_A_USER_CANCELED</td><td width="10%">90</td><td width="30%">User canceled</td></tr>
<tr><td width="55%">GNUTLS_A_NO_RENEGOTIATION</td><td width="10%">100</td><td width="30%">No renegotiation is allowed</td></tr>
<tr><td width="55%">GNUTLS_A_MISSING_EXTENSION</td><td width="10%">109</td><td width="30%">An extension was expected but was not seen</td></tr>
<tr><td width="55%">GNUTLS_A_UNSUPPORTED_EXTENSION</td><td width="10%">110</td><td width="30%">An unsupported extension was sent</td></tr>
<tr><td width="55%">GNUTLS_A_CERTIFICATE_UNOBTAINABLE</td><td width="10%">111</td><td width="30%">Could not retrieve the specified certificate</td></tr>
<tr><td width="55%">GNUTLS_A_UNRECOGNIZED_NAME</td><td width="10%">112</td><td width="30%">The server name sent was not recognized</td></tr>
<tr><td width="55%">GNUTLS_A_UNKNOWN_PSK_IDENTITY</td><td width="10%">115</td><td width="30%">The SRP/PSK username is missing or not known</td></tr>
<tr><td width="55%">GNUTLS_A_CERTIFICATE_REQUIRED</td><td width="10%">116</td><td width="30%">Certificate is required</td></tr>
<tr><td width="55%">GNUTLS_A_NO_APPLICATION_PROTOCOL</td><td width="10%">120</td><td width="30%">No supported application protocol could be negotiated</td></tr>
</tbody>
</table>

<hr>
</div>
<div class="section-level-extent" id="The-TLS-Handshake-Protocol">
<div class="nav-panel">
<p>
Next: <a href="#TLS-Extensions" accesskey="n" rel="next">TLS extensions</a>, Previous: <a href="#The-TLS-Alert-Protocol" accesskey="p" rel="prev">The TLS alert protocol</a>, Up: <a href="#Introduction-to-TLS" accesskey="u" rel="up">Introduction to <abbr class="acronym">TLS</abbr> and <abbr class="acronym">DTLS</abbr></a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="The-TLS-handshake-protocol"><span>3.5 The TLS handshake protocol<a class="copiable-link" href="#The-TLS-handshake-protocol"> &para;</a></span></h3>
<a class="anchor" id="The-Handshake-Protocol"></a><a class="index-entry-id" id="index-handshake-protocol"></a>

<p>The handshake protocol is responsible for the ciphersuite negotiation,
the initial key exchange, and the authentication of the two peers.
This is fully controlled by the application layer, thus your program
has to set up the required parameters. The main handshake function
is <a class="ref" href="#gnutls_005fhandshake">gnutls_handshake</a>. In the next paragraphs we elaborate on
the handshake protocol, i.e., the ciphersuite negotiation.
</p>



<ul class="mini-toc">
<li><a href="#TLS-Cipher-Suites" accesskey="1">TLS ciphersuites</a></li>
<li><a href="#Authentication" accesskey="2">Authentication</a></li>
<li><a href="#Client-Authentication" accesskey="3">Client authentication</a></li>
<li><a href="#Resuming-Sessions" accesskey="4">Resuming sessions</a></li>
</ul>
<hr>
<div class="subsection-level-extent" id="TLS-Cipher-Suites">
<div class="nav-panel">
<p>
Next: <a href="#Authentication" accesskey="n" rel="next">Authentication</a>, Up: <a href="#The-TLS-Handshake-Protocol" accesskey="u" rel="up">The TLS handshake protocol</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="TLS-ciphersuites"><span>3.5.1 TLS ciphersuites<a class="copiable-link" href="#TLS-ciphersuites"> &para;</a></span></h4>

<p>The TLS cipher suites have slightly different meaning under different
protocols. Under <abbr class="acronym">TLS 1.3</abbr>, a cipher suite indicates the symmetric
encryption algorithm in use, as well as the pseudo-random function (PRF)
used in the TLS session.
</p>
<p>Under TLS 1.2 or early the handshake protocol negotiates cipher suites of
a special form illustrated by the <code class="code">TLS_DHE_RSA_WITH_3DES_CBC_SHA</code> cipher suite name.
A typical cipher suite contains these parameters:
</p>
<ul class="itemize mark-bullet">
<li>The key exchange algorithm.
<code class="code">DHE_RSA</code> in the example.

</li><li>The Symmetric encryption algorithm and mode
<code class="code">3DES_CBC</code> in this example.

</li><li>The MAC<a class="footnote" id="DOCF5" href="#FOOT5"><sup>5</sup></a> algorithm used for authentication.
<code class="code">MAC_SHA</code> is used in the above example.

</li></ul>

<p>The cipher suite negotiated in the handshake protocol will affect the
record protocol, by enabling encryption and data authentication.  Note
that you should not over rely on <abbr class="acronym">TLS</abbr> to negotiate the
strongest available cipher suite. Do not enable ciphers and algorithms
that you consider weak.
</p>
<p>All the supported ciphersuites are listed in <a class="ref" href="#ciphersuites">ciphersuites</a>.
</p>
<hr>
</div>
<div class="subsection-level-extent" id="Authentication">
<div class="nav-panel">
<p>
Next: <a href="#Client-Authentication" accesskey="n" rel="next">Client authentication</a>, Previous: <a href="#TLS-Cipher-Suites" accesskey="p" rel="prev">TLS ciphersuites</a>, Up: <a href="#The-TLS-Handshake-Protocol" accesskey="u" rel="up">The TLS handshake protocol</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Authentication-1"><span>3.5.2 Authentication<a class="copiable-link" href="#Authentication-1"> &para;</a></span></h4>

<p>The key exchange algorithms of the <abbr class="acronym">TLS</abbr> protocol offer
authentication, which is a prerequisite for a secure connection.
The available authentication methods in <abbr class="acronym">GnuTLS</abbr>, under
TLS 1.3 or earlier versions, follow.
</p>
<ul class="itemize mark-bullet">
<li>Certificate authentication: Authenticated key exchange using public key infrastructure and X.509 certificates.
</li><li><abbr class="acronym">PSK</abbr> authentication: Authenticated key exchange using a pre-shared key.

</li></ul>

<p>Under TLS 1.2 or earlier versions, the following authentication methods
are also available.
</p>
<ul class="itemize mark-bullet">
<li><abbr class="acronym">SRP</abbr> authentication: Authenticated key exchange using a password.
</li><li>Anonymous authentication: Key exchange without peer authentication.

</li></ul>

<hr>
</div>
<div class="subsection-level-extent" id="Client-Authentication">
<div class="nav-panel">
<p>
Next: <a href="#Resuming-Sessions" accesskey="n" rel="next">Resuming sessions</a>, Previous: <a href="#Authentication" accesskey="p" rel="prev">Authentication</a>, Up: <a href="#The-TLS-Handshake-Protocol" accesskey="u" rel="up">The TLS handshake protocol</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Client-authentication"><span>3.5.3 Client authentication<a class="copiable-link" href="#Client-authentication"> &para;</a></span></h4>
<a class="index-entry-id" id="index-client-certificate-authentication"></a>

<p>In the case of ciphersuites that use certificate authentication, the
authentication of the client is optional in <abbr class="acronym">TLS</abbr>.  A server
may request a certificate from the client using the
<a class="ref" href="#gnutls_005fcertificate_005fserver_005fset_005frequest">gnutls_certificate_server_set_request</a> function. We elaborate
in <a class="ref" href="#Certificate-credentials">Certificates</a>.
</p>
<hr>
</div>
<div class="subsection-level-extent" id="Resuming-Sessions">
<div class="nav-panel">
<p>
Previous: <a href="#Client-Authentication" accesskey="p" rel="prev">Client authentication</a>, Up: <a href="#The-TLS-Handshake-Protocol" accesskey="u" rel="up">The TLS handshake protocol</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Resuming-sessions"><span>3.5.4 Resuming sessions<a class="copiable-link" href="#Resuming-sessions"> &para;</a></span></h4>
<a class="anchor" id="resume"></a><a class="index-entry-id" id="index-resuming-sessions"></a>
<a class="index-entry-id" id="index-session-resumption"></a>

<p>The TLS handshake process performs expensive calculations
and a busy server might easily be put under load. To
reduce the load, session resumption may be used. This
is a feature of the <abbr class="acronym">TLS</abbr> protocol which allows a
client to connect to a server after a successful handshake, without
the expensive calculations.  This is achieved by re-using the previously
established keys, meaning the server needs to store the state of established
connections (unless session tickets are used &ndash; <a class="ref" href="#Session-tickets">Session tickets</a>).
</p>
<p>Session resumption is an integral part of <abbr class="acronym">GnuTLS</abbr>, and
<a class="ref" href="#Session-resumption">Session resumption</a>, <a class="ref" href="#ex_002dresume_002dclient">ex-resume-client</a> illustrate typical
uses of it.
</p>
<hr>
</div>
</div>
<div class="section-level-extent" id="TLS-Extensions">
<div class="nav-panel">
<p>
Next: <a href="#How-to-use-TLS-in-application-protocols" accesskey="n" rel="next">How to use <abbr class="acronym">TLS</abbr> in application protocols</a>, Previous: <a href="#The-TLS-Handshake-Protocol" accesskey="p" rel="prev">The TLS handshake protocol</a>, Up: <a href="#Introduction-to-TLS" accesskey="u" rel="up">Introduction to <abbr class="acronym">TLS</abbr> and <abbr class="acronym">DTLS</abbr></a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="TLS-extensions"><span>3.6 TLS extensions<a class="copiable-link" href="#TLS-extensions"> &para;</a></span></h3>
<a class="index-entry-id" id="index-TLS-extensions"></a>

<p>A number of extensions to the <abbr class="acronym">TLS</abbr> protocol have been
proposed mainly in [<a class="ref" href="#TLSEXT">TLSEXT</a>]. The extensions supported
in <abbr class="acronym">GnuTLS</abbr> are discussed in the subsections that follow.
</p>

<ul class="mini-toc">
<li><a href="#Maximum-fragment-length-negotiation" accesskey="1">Maximum fragment length negotiation</a></li>
<li><a href="#Server-name-indication" accesskey="2">Server name indication</a></li>
<li><a href="#Session-tickets" accesskey="3">Session tickets</a></li>
<li><a href="#HeartBeat" accesskey="4">HeartBeat</a></li>
<li><a href="#Safe-renegotiation" accesskey="5">Safe renegotiation</a></li>
<li><a href="#OCSP-status-request" accesskey="6">OCSP status request</a></li>
<li><a href="#SRTP" accesskey="7">SRTP</a></li>
<li><a href="#False-Start" accesskey="8">False Start</a></li>
<li><a href="#Application-Layer-Protocol-Negotiation-_0028ALPN_0029" accesskey="9">Application Layer Protocol Negotiation (ALPN)</a></li>
<li><a href="#Extensions-and-Supplemental-Data">Extensions and Supplemental Data</a></li>
</ul>
<hr>
<div class="subsection-level-extent" id="Maximum-fragment-length-negotiation">
<div class="nav-panel">
<p>
Next: <a href="#Server-name-indication" accesskey="n" rel="next">Server name indication</a>, Up: <a href="#TLS-Extensions" accesskey="u" rel="up">TLS extensions</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Maximum-fragment-length-negotiation-1"><span>3.6.1 Maximum fragment length negotiation<a class="copiable-link" href="#Maximum-fragment-length-negotiation-1"> &para;</a></span></h4>
<a class="index-entry-id" id="index-TLS-extensions-1"></a>
<a class="index-entry-id" id="index-maximum-fragment-length"></a>

<p>This extension allows a <abbr class="acronym">TLS</abbr> implementation to negotiate a
smaller value for record packet maximum length. This extension may be
useful to clients with constrained capabilities. The functions shown
below can be used to control this extension.
</p>
<dl class="table">
<dt><code class="code"><var class="var">size_t</var> <a class="ref" href="#gnutls_005frecord_005fget_005fmax_005fsize">gnutls_record_get_max_size</a> (gnutls_session_t <var class="var">session</var>)</code></dt>
<dt><code class="code"><var class="var">ssize_t</var> <a class="ref" href="#gnutls_005frecord_005fset_005fmax_005fsize">gnutls_record_set_max_size</a> (gnutls_session_t <var class="var">session</var>, size_t <var class="var">size</var>)</code></dt>
</dl>

<hr>
</div>
<div class="subsection-level-extent" id="Server-name-indication">
<div class="nav-panel">
<p>
Next: <a href="#Session-tickets" accesskey="n" rel="next">Session tickets</a>, Previous: <a href="#Maximum-fragment-length-negotiation" accesskey="p" rel="prev">Maximum fragment length negotiation</a>, Up: <a href="#TLS-Extensions" accesskey="u" rel="up">TLS extensions</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Server-name-indication-1"><span>3.6.2 Server name indication<a class="copiable-link" href="#Server-name-indication-1"> &para;</a></span></h4>
<a class="anchor" id="serverind"></a><a class="index-entry-id" id="index-TLS-extensions-2"></a>
<a class="index-entry-id" id="index-server-name-indication"></a>

<p>A common problem in <abbr class="acronym">HTTPS</abbr> servers is the fact that the
<abbr class="acronym">TLS</abbr> protocol is not aware of the hostname that a client
connects to, when the handshake procedure begins. For that reason the
<abbr class="acronym">TLS</abbr> server has no way to know which certificate to send.
</p>
<p>This extension solves that problem within the <abbr class="acronym">TLS</abbr> protocol,
and allows a client to send the HTTP hostname before the handshake
begins within the first handshake packet.  The functions
<a class="ref" href="#gnutls_005fserver_005fname_005fset">gnutls_server_name_set</a> and <a class="ref" href="#gnutls_005fserver_005fname_005fget">gnutls_server_name_get</a> can be
used to enable this extension, or to retrieve the name sent by a
client.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fserver_005fname_005fset">gnutls_server_name_set</a> (gnutls_session_t <var class="var">session</var>, gnutls_server_name_type_t <var class="var">type</var>, const void * <var class="var">name</var>, size_t <var class="var">name_length</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fserver_005fname_005fget">gnutls_server_name_get</a> (gnutls_session_t <var class="var">session</var>, void * <var class="var">data</var>, size_t * <var class="var">data_length</var>, unsigned int * <var class="var">type</var>, unsigned int <var class="var">indx</var>)</code></dt>
</dl>

<hr>
</div>
<div class="subsection-level-extent" id="Session-tickets">
<div class="nav-panel">
<p>
Next: <a href="#HeartBeat" accesskey="n" rel="next">HeartBeat</a>, Previous: <a href="#Server-name-indication" accesskey="p" rel="prev">Server name indication</a>, Up: <a href="#TLS-Extensions" accesskey="u" rel="up">TLS extensions</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Session-tickets-1"><span>3.6.3 Session tickets<a class="copiable-link" href="#Session-tickets-1"> &para;</a></span></h4>
<a class="index-entry-id" id="index-TLS-extensions-3"></a>
<a class="index-entry-id" id="index-session-tickets"></a>
<a class="index-entry-id" id="index-tickets"></a>

<p>To resume a TLS session, the server normally stores session parameters.  This
complicates deployment, and can be avoided by delegating the storage
to the client. Because session parameters are sensitive they are encrypted
and authenticated with a key only known to the server and then sent to the
client. The Session Tickets extension is described in RFC 5077 [<a class="ref" href="#TLSTKT">TLSTKT</a>].
</p>
<p>A disadvantage of session tickets is that they eliminate the effects of
forward secrecy when a server uses the same key for long time. That is,
the secrecy of all sessions on a server using tickets depends on the ticket
key being kept secret. For that reason server keys should be rotated and discarded
regularly.
</p>
<p>Since version 3.1.3 GnuTLS clients transparently support session tickets,
unless forward secrecy is explicitly requested (with the PFS priority string).
</p>
<p>Under TLS 1.3 session tickets are mandatory for session resumption, and they
do not share the forward secrecy concerns as with TLS 1.2 or earlier.
</p>
<hr>
</div>
<div class="subsection-level-extent" id="HeartBeat">
<div class="nav-panel">
<p>
Next: <a href="#Safe-renegotiation" accesskey="n" rel="next">Safe renegotiation</a>, Previous: <a href="#Session-tickets" accesskey="p" rel="prev">Session tickets</a>, Up: <a href="#TLS-Extensions" accesskey="u" rel="up">TLS extensions</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="HeartBeat-1"><span>3.6.4 HeartBeat<a class="copiable-link" href="#HeartBeat-1"> &para;</a></span></h4>
<a class="index-entry-id" id="index-TLS-extensions-4"></a>
<a class="index-entry-id" id="index-heartbeat"></a>

<p>This is a TLS extension that allows to ping and receive confirmation from the peer,
and is described in [<a class="ref" href="#RFC6520">RFC6520</a>]. The extension is disabled by default and
<a class="ref" href="#gnutls_005fheartbeat_005fenable">gnutls_heartbeat_enable</a> can be used to enable it. A policy
may be negotiated to only allow sending heartbeat messages or sending and receiving.
The current session policy can be checked with <a class="ref" href="#gnutls_005fheartbeat_005fallowed">gnutls_heartbeat_allowed</a>.
The requests coming from the peer result to <code class="code">GNUTLS_E_HEARTBEAT_PING_RECEIVED</code>
being returned from the receive function. Ping requests to peer can be send via
<a class="ref" href="#gnutls_005fheartbeat_005fping">gnutls_heartbeat_ping</a>.
</p>
<dl class="table">
<dt><code class="code"><var class="var">unsigned</var> <a class="ref" href="#gnutls_005fheartbeat_005fallowed">gnutls_heartbeat_allowed</a> (gnutls_session_t <var class="var">session</var>, unsigned int <var class="var">type</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fheartbeat_005fenable">gnutls_heartbeat_enable</a> (gnutls_session_t <var class="var">session</var>, unsigned int <var class="var">type</var>)</code></dt>
</dl>

<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fheartbeat_005fping">gnutls_heartbeat_ping</a> (gnutls_session_t <var class="var">session</var>, size_t <var class="var">data_size</var>, unsigned int <var class="var">max_tries</var>, unsigned int <var class="var">flags</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fheartbeat_005fpong">gnutls_heartbeat_pong</a> (gnutls_session_t <var class="var">session</var>, unsigned int <var class="var">flags</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fheartbeat_005fset_005ftimeouts">gnutls_heartbeat_set_timeouts</a> (gnutls_session_t <var class="var">session</var>, unsigned int <var class="var">retrans_timeout</var>, unsigned int <var class="var">total_timeout</var>)</code></dt>
<dt><code class="code"><var class="var">unsigned int</var> <a class="ref" href="#gnutls_005fheartbeat_005fget_005ftimeout">gnutls_heartbeat_get_timeout</a> (gnutls_session_t <var class="var">session</var>)</code></dt>
</dl>

<hr>
</div>
<div class="subsection-level-extent" id="Safe-renegotiation">
<div class="nav-panel">
<p>
Next: <a href="#OCSP-status-request" accesskey="n" rel="next">OCSP status request</a>, Previous: <a href="#HeartBeat" accesskey="p" rel="prev">HeartBeat</a>, Up: <a href="#TLS-Extensions" accesskey="u" rel="up">TLS extensions</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Safe-renegotiation-1"><span>3.6.5 Safe renegotiation<a class="copiable-link" href="#Safe-renegotiation-1"> &para;</a></span></h4>
<a class="index-entry-id" id="index-renegotiation"></a>
<a class="index-entry-id" id="index-safe-renegotiation"></a>

<p>TLS gives the option to two communicating parties to renegotiate
and update their security parameters. One useful example of this feature
was for a client to initially connect using anonymous negotiation to a
server, and the renegotiate using some authenticated ciphersuite. This occurred
to avoid having the client sending its credentials in the clear.
</p>
<p>However this renegotiation, as initially designed would not ensure that
the party one is renegotiating is the same as the one in the initial negotiation.
For example one server could forward all renegotiation traffic to an other
server who will see this traffic as an initial negotiation attempt.
</p>
<p>This might be seen as a valid design decision, but it seems it was
not widely known or understood, thus today some application protocols use the TLS
renegotiation feature in a manner that enables a malicious server to insert
content of his choice in the beginning of a TLS session.
</p>
<p>The most prominent vulnerability was with HTTPS. There servers request
a renegotiation to enforce an anonymous user to use a certificate in order
to access certain parts of a web site.  The
attack works by having the attacker simulate a client and connect to a
server, with server-only authentication, and send some data intended
to cause harm.  The server will then require renegotiation from him
in order to perform the request.
When the proper client attempts to contact the server,
the attacker hijacks that connection and forwards traffic to
the initial server that requested renegotiation.  The
attacker will not be able to read the data exchanged between the
client and the server.  However, the server will (incorrectly) assume
that the initial request sent by the attacker was sent by the now authenticated
client.  The result is a prefix plain-text injection attack.
</p>
<p>The above is just one example.  Other vulnerabilities exists that do
not rely on the TLS renegotiation to change the client&rsquo;s authenticated
status (either TLS or application layer).
</p>
<p>While fixing these application protocols and implementations would be
one natural reaction, an extension to TLS has been designed that
cryptographically binds together any renegotiated handshakes with the
initial negotiation.  When the extension is used, the attack is
detected and the session can be terminated.  The extension is
specified in [<a class="ref" href="#RFC5746">RFC5746</a>].
</p>
<p>GnuTLS supports the safe renegotiation extension.  The default
behavior is as follows.  Clients will attempt to negotiate the safe
renegotiation extension when talking to servers.  Servers will accept
the extension when presented by clients.  Clients and servers will
permit an initial handshake to complete even when the other side does
not support the safe renegotiation extension.  Clients and servers
will refuse renegotiation attempts when the extension has not been
negotiated.
</p>
<p>Note that permitting clients to connect to servers when the safe
renegotiation extension is not enabled, is open up for attacks.
Changing this default behavior would prevent interoperability against
the majority of deployed servers out there.  We will reconsider this
default behavior in the future when more servers have been upgraded.
Note that it is easy to configure clients to always require the safe
renegotiation extension from servers.
</p>
<p>To modify the default behavior, we have introduced some new priority
strings (see <a class="ref" href="#Priority-Strings">Priority strings</a>).
The <code class="code">%UNSAFE_RENEGOTIATION</code> priority string permits
(re-)handshakes even when the safe renegotiation extension was not
negotiated. The default behavior is <code class="code">%PARTIAL_RENEGOTIATION</code> that will
prevent renegotiation with clients and servers not supporting the
extension. This is secure for servers but leaves clients vulnerable
to some attacks, but this is a trade-off between security and compatibility
with old servers. The <code class="code">%SAFE_RENEGOTIATION</code> priority string makes
clients and servers require the extension for every handshake. The latter
is the most secure option for clients, at the cost of not being able
to connect to legacy servers. Servers will also deny clients that
do not support the extension from connecting.
</p>
<p>It is possible to disable use of the extension completely, in both
clients and servers, by using the <code class="code">%DISABLE_SAFE_RENEGOTIATION</code>
priority string however we strongly recommend you to only do this for
debugging and test purposes.
</p>
<p>The default values if the flags above are not specified are:
</p><dl class="table">
<dt><code class="code">Server:</code></dt>
<dd><p>%PARTIAL_RENEGOTIATION
</p>
</dd>
<dt><code class="code">Client:</code></dt>
<dd><p>%PARTIAL_RENEGOTIATION
</p>
</dd>
</dl>

<p>For applications we have introduced a new API related to safe
renegotiation.  The <a class="ref" href="#gnutls_005fsafe_005frenegotiation_005fstatus">gnutls_safe_renegotiation_status</a> function is
used to check if the extension has been negotiated on a session, and
can be used both by clients and servers.
</p>
<hr>
</div>
<div class="subsection-level-extent" id="OCSP-status-request">
<div class="nav-panel">
<p>
Next: <a href="#SRTP" accesskey="n" rel="next">SRTP</a>, Previous: <a href="#Safe-renegotiation" accesskey="p" rel="prev">Safe renegotiation</a>, Up: <a href="#TLS-Extensions" accesskey="u" rel="up">TLS extensions</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="OCSP-status-request-1"><span>3.6.6 OCSP status request<a class="copiable-link" href="#OCSP-status-request-1"> &para;</a></span></h4>
<a class="index-entry-id" id="index-OCSP-status-request"></a>
<a class="index-entry-id" id="index-Certificate-status-request"></a>

<p>The Online Certificate Status Protocol (OCSP) is a protocol that allows the
client to verify the server certificate for revocation without messing with
certificate revocation lists. Its drawback is that it requires the client
to connect to the server&rsquo;s CA OCSP server and request the status of the
certificate. This extension however, enables a TLS server to include
its CA OCSP server response in the handshake. That is an HTTPS server
may periodically run <code class="code">ocsptool</code> (see <a class="ref" href="#ocsptool-Invocation">Invoking ocsptool</a>) to obtain
its certificate revocation status and serve it to the clients. That
way a client avoids an additional connection to the OCSP server.
</p>
<p>See <a class="ref" href="#OCSP-stapling">OCSP stapling</a> for further information.
</p>
<p>Since version 3.1.3 GnuTLS clients transparently support the certificate status
request.
</p>
<hr>
</div>
<div class="subsection-level-extent" id="SRTP">
<div class="nav-panel">
<p>
Next: <a href="#False-Start" accesskey="n" rel="next">False Start</a>, Previous: <a href="#OCSP-status-request" accesskey="p" rel="prev">OCSP status request</a>, Up: <a href="#TLS-Extensions" accesskey="u" rel="up">TLS extensions</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="SRTP-1"><span>3.6.7 SRTP<a class="copiable-link" href="#SRTP-1"> &para;</a></span></h4>
<a class="index-entry-id" id="index-SRTP"></a>
<a class="index-entry-id" id="index-Secure-RTP"></a>

<p>The TLS protocol was extended in [<a class="ref" href="#RFC5764">RFC5764</a>] to provide keying material to the
Secure RTP (SRTP) protocol. The SRTP protocol provides an encapsulation of encrypted
data that is optimized for voice data. With the SRTP TLS extension two peers can
negotiate keys using TLS or DTLS and obtain keying material for use with SRTP. The
available SRTP profiles are listed below.
</p>
<div class="float" id="gnutls_005fsrtp_005fprofile_005ft">


<dl class="table">
<dt><code class="code">GNUTLS_SRTP_AES128_CM_HMAC_SHA1_80</code></dt>
<dd><p>128 bit AES with a 80 bit HMAC-SHA1
</p></dd>
<dt><code class="code">GNUTLS_SRTP_AES128_CM_HMAC_SHA1_32</code></dt>
<dd><p>128 bit AES with a 32 bit HMAC-SHA1
</p></dd>
<dt><code class="code">GNUTLS_SRTP_NULL_HMAC_SHA1_80</code></dt>
<dd><p>NULL cipher with a 80 bit HMAC-SHA1
</p></dd>
<dt><code class="code">GNUTLS_SRTP_NULL_HMAC_SHA1_32</code></dt>
<dd><p>NULL cipher with a 32 bit HMAC-SHA1
</p></dd>
<dt><code class="code">GNUTLS_SRTP_AEAD_AES_128_GCM</code></dt>
<dd><p>128 bit AES with GCM
</p></dd>
<dt><code class="code">GNUTLS_SRTP_AEAD_AES_256_GCM</code></dt>
<dd><p>256 bit AES with GCM
</p></dd>
</dl>
<div class="caption"><p><strong class="strong">Figure 3.2: </strong>Supported SRTP profiles</p></div></div>
<p>To enable use the following functions.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fsrtp_005fset_005fprofile">gnutls_srtp_set_profile</a> (gnutls_session_t <var class="var">session</var>, gnutls_srtp_profile_t <var class="var">profile</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fsrtp_005fset_005fprofile_005fdirect">gnutls_srtp_set_profile_direct</a> (gnutls_session_t <var class="var">session</var>, const char * <var class="var">profiles</var>, const char ** <var class="var">err_pos</var>)</code></dt>
</dl>

<p>To obtain the negotiated keys use the function below.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsrtp_005fget_005fkeys"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_srtp_get_keys</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, void * <var class="var">key_material</var>, unsigned int <var class="var">key_material_size</var>, gnutls_datum_t * <var class="var">client_key</var>, gnutls_datum_t * <var class="var">client_salt</var>, gnutls_datum_t * <var class="var">server_key</var>, gnutls_datum_t * <var class="var">server_salt</var>)</code><a class="copiable-link" href="#index-gnutls_005fsrtp_005fget_005fkeys"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">key_material</var>: Space to hold the generated key material
</p>
<p><var class="var">key_material_size</var>: The maximum size of the key material
</p>
<p><var class="var">client_key</var>: The master client write key, pointing inside the key material
</p>
<p><var class="var">client_salt</var>: The master client write salt, pointing inside the key material
</p>
<p><var class="var">server_key</var>: The master server write key, pointing inside the key material
</p>
<p><var class="var">server_salt</var>: The master server write salt, pointing inside the key material
</p>
<p>This is a helper function to generate the keying material for SRTP.
It requires the space of the key material to be pre-allocated (should be at least
2x the maximum key size and salt size). The  <code class="code">client_key</code> ,  <code class="code">client_salt</code> ,  <code class="code">server_key</code> and  <code class="code">server_salt</code> are convenience datums that point inside the key material. They may
be <code class="code">NULL</code> .
</p>
<p><strong class="strong">Returns:</strong> On success the size of the key material is returned,
otherwise, <code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  if the buffer given is not 
sufficient, or a negative error code.
</p>
<p>Since 3.1.4
</p></dd></dl>

<p>Other helper functions are listed below.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fsrtp_005fget_005fselected_005fprofile">gnutls_srtp_get_selected_profile</a> (gnutls_session_t <var class="var">session</var>, gnutls_srtp_profile_t * <var class="var">profile</var>)</code></dt>
<dt><code class="code"><var class="var">const char *</var> <a class="ref" href="#gnutls_005fsrtp_005fget_005fprofile_005fname">gnutls_srtp_get_profile_name</a> (gnutls_srtp_profile_t <var class="var">profile</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fsrtp_005fget_005fprofile_005fid">gnutls_srtp_get_profile_id</a> (const char * <var class="var">name</var>, gnutls_srtp_profile_t * <var class="var">profile</var>)</code></dt>
</dl>

<hr>
</div>
<div class="subsection-level-extent" id="False-Start">
<div class="nav-panel">
<p>
Next: <a href="#Application-Layer-Protocol-Negotiation-_0028ALPN_0029" accesskey="n" rel="next">Application Layer Protocol Negotiation (ALPN)</a>, Previous: <a href="#SRTP" accesskey="p" rel="prev">SRTP</a>, Up: <a href="#TLS-Extensions" accesskey="u" rel="up">TLS extensions</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="False-Start-1"><span>3.6.8 False Start<a class="copiable-link" href="#False-Start-1"> &para;</a></span></h4>
<a class="index-entry-id" id="index-False-Start"></a>
<a class="index-entry-id" id="index-TLS-False-Start"></a>

<p>The TLS protocol was extended in [<a class="ref" href="#RFC7918">RFC7918</a>] to allow the client
to send data to server in a single round trip. This change however operates on the borderline
of the TLS protocol security guarantees and should be used for the cases where the reduced
latency outperforms the risk of an adversary intercepting the transferred data. In GnuTLS
applications can use the <abbr class="acronym">GNUTLS_ENABLE_FALSE_START</abbr> as option to <a class="ref" href="#gnutls_005finit">gnutls_init</a>
to request an early return of the <a class="ref" href="#gnutls_005fhandshake">gnutls_handshake</a> function. After that early
return the application is expected to transfer any data to be piggybacked on the last handshake
message.
</p>
<p>After handshake&rsquo;s early termination, the application is expected to transmit
data using <a class="ref" href="#gnutls_005frecord_005fsend">gnutls_record_send</a>, and call <a class="ref" href="#gnutls_005frecord_005frecv">gnutls_record_recv</a> on
any received data as soon, to ensure that handshake completes timely. That is, especially
relevant for applications which set an explicit time limit for the handshake process
via <a class="ref" href="#gnutls_005fhandshake_005fset_005ftimeout">gnutls_handshake_set_timeout</a>.
</p>
<p>Note however, that the API ensures that the early return will not happen
if the false start requirements are not satisfied. That is, on ciphersuites which are not
enabled for false start or on insufficient key sizes, the handshake
process will complete properly (i.e., no early return). To verify that false start was used you
may use <a class="ref" href="#gnutls_005fsession_005fget_005fflags">gnutls_session_get_flags</a> and check for the <abbr class="acronym">GNUTLS_SFLAGS_FALSE_START</abbr>
flag. For GnuTLS the false start is enabled for the following
key exchange methods (see [<a class="ref" href="#RFC7918">RFC7918</a>] for rationale)
</p><ul class="itemize mark-bullet">
<li>DHE
</li><li>ECDHE
</li></ul>
<p>but only when the negotiated parameters exceed <code class="code">GNUTLS_SEC_PARAM_HIGH</code>
&ndash;see <a class="ref" href="#tab_003akey_002dsizes">Table 6.7</a>, and when under (D)TLS 1.2 or later.
</p>
<hr>
</div>
<div class="subsection-level-extent" id="Application-Layer-Protocol-Negotiation-_0028ALPN_0029">
<div class="nav-panel">
<p>
Next: <a href="#Extensions-and-Supplemental-Data" accesskey="n" rel="next">Extensions and Supplemental Data</a>, Previous: <a href="#False-Start" accesskey="p" rel="prev">False Start</a>, Up: <a href="#TLS-Extensions" accesskey="u" rel="up">TLS extensions</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Application-Layer-Protocol-Negotiation-_0028ALPN_0029-1"><span>3.6.9 Application Layer Protocol Negotiation (ALPN)<a class="copiable-link" href="#Application-Layer-Protocol-Negotiation-_0028ALPN_0029-1"> &para;</a></span></h4>
<a class="index-entry-id" id="index-ALPN"></a>
<a class="index-entry-id" id="index-Application-Layer-Protocol-Negotiation"></a>

<p>The TLS protocol was extended in <code class="code">RFC7301</code>
to provide the application layer a method of
negotiating the application protocol version. This allows for negotiation
of the application protocol during the TLS handshake, thus reducing
round-trips. The application protocol is described by an opaque
string. To enable, use the following functions.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005falpn_005fset_005fprotocols">gnutls_alpn_set_protocols</a> (gnutls_session_t <var class="var">session</var>, const gnutls_datum_t * <var class="var">protocols</var>, unsigned <var class="var">protocols_size</var>, unsigned int <var class="var">flags</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005falpn_005fget_005fselected_005fprotocol">gnutls_alpn_get_selected_protocol</a> (gnutls_session_t <var class="var">session</var>, gnutls_datum_t * <var class="var">protocol</var>)</code></dt>
</dl>

<p>Note that these functions are intended to be used with protocols that are
registered in the Application Layer Protocol Negotiation IANA registry. While
you can use them for other protocols (at the risk of collisions), it is preferable
to register them.
</p>
<hr>
</div>
<div class="subsection-level-extent" id="Extensions-and-Supplemental-Data">
<div class="nav-panel">
<p>
Previous: <a href="#Application-Layer-Protocol-Negotiation-_0028ALPN_0029" accesskey="p" rel="prev">Application Layer Protocol Negotiation (ALPN)</a>, Up: <a href="#TLS-Extensions" accesskey="u" rel="up">TLS extensions</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Extensions-and-Supplemental-Data-1"><span>3.6.10 Extensions and Supplemental Data<a class="copiable-link" href="#Extensions-and-Supplemental-Data-1"> &para;</a></span></h4>
<a class="index-entry-id" id="index-Supplemental-data"></a>

<p>It is possible to transfer supplemental data during the TLS handshake, following
[<a class="ref" href="#RFC4680">RFC4680</a>]. This is for &quot;custom&quot; protocol modifications for applications which
may want to transfer additional data (e.g. additional authentication messages). Such
an exchange requires a custom extension to be registered.
The provided API for this functionality is low-level and described in <a class="ref" href="#TLS-Hello-Extension-Handling">TLS Extension Handling</a>.
</p>
<hr>
</div>
</div>
<div class="section-level-extent" id="How-to-use-TLS-in-application-protocols">
<div class="nav-panel">
<p>
Next: <a href="#On-SSL-2-and-older-protocols" accesskey="n" rel="next">On SSL 2 and older protocols</a>, Previous: <a href="#TLS-Extensions" accesskey="p" rel="prev">TLS extensions</a>, Up: <a href="#Introduction-to-TLS" accesskey="u" rel="up">Introduction to <abbr class="acronym">TLS</abbr> and <abbr class="acronym">DTLS</abbr></a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="How-to-use-TLS-in-application-protocols-1"><span>3.7 How to use <abbr class="acronym">TLS</abbr> in application protocols<a class="copiable-link" href="#How-to-use-TLS-in-application-protocols-1"> &para;</a></span></h3>

<p>This chapter is intended to provide some hints on how to use
<abbr class="acronym">TLS</abbr> over simple custom made application protocols.  The
discussion below mainly refers to the <abbr class="acronym">TCP/IP</abbr> transport layer
but may be extended to other ones too.
</p>

<ul class="mini-toc">
<li><a href="#Separate-ports" accesskey="1">Separate ports</a></li>
<li><a href="#Upward-negotiation" accesskey="2">Upward negotiation</a></li>
</ul>
<hr>
<div class="subsection-level-extent" id="Separate-ports">
<div class="nav-panel">
<p>
Next: <a href="#Upward-negotiation" accesskey="n" rel="next">Upward negotiation</a>, Up: <a href="#How-to-use-TLS-in-application-protocols" accesskey="u" rel="up">How to use <abbr class="acronym">TLS</abbr> in application protocols</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Separate-ports-1"><span>3.7.1 Separate ports<a class="copiable-link" href="#Separate-ports-1"> &para;</a></span></h4>

<p>Traditionally <abbr class="acronym">SSL</abbr> was used in application protocols by
assigning a new port number for the secure services. By doing this two
separate ports were assigned, one for the non-secure sessions, and one
for the secure sessions. This method ensures that if a user requests a
secure session then the client will attempt to connect to the secure port
and fail otherwise. The only possible attack with this method is to perform
a denial of service attack. The most famous example of this method is
&ldquo;HTTP over TLS&rdquo; or <abbr class="acronym">HTTPS</abbr> protocol [<a class="ref" href="#RFC2818">RFC2818</a>].
</p>
<p>Despite its wide use, this method has several issues. This
approach starts the <abbr class="acronym">TLS</abbr> Handshake procedure just after the
client connects on the &mdash;so called&mdash; secure port.  That way the
<abbr class="acronym">TLS</abbr> protocol does not know anything about the client, and
popular methods like the host advertising in HTTP do not
work<a class="footnote" id="DOCF6" href="#FOOT6"><sup>6</sup></a>.  There is no way for the client to say &ldquo;I
connected to YYY server&rdquo; before the Handshake starts, so the server
cannot possibly know which certificate to use.
</p>
<p>Other than that it requires two separate ports to run a single
service, which is unnecessary complication. Due to the fact that there
is a limitation on the available privileged ports, this approach was
soon deprecated in favor of upward negotiation.
</p>
<hr>
</div>
<div class="subsection-level-extent" id="Upward-negotiation">
<div class="nav-panel">
<p>
Previous: <a href="#Separate-ports" accesskey="p" rel="prev">Separate ports</a>, Up: <a href="#How-to-use-TLS-in-application-protocols" accesskey="u" rel="up">How to use <abbr class="acronym">TLS</abbr> in application protocols</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Upward-negotiation-1"><span>3.7.2 Upward negotiation<a class="copiable-link" href="#Upward-negotiation-1"> &para;</a></span></h4>

<p>Other application protocols<a class="footnote" id="DOCF7" href="#FOOT7"><sup>7</sup></a>  use a
different approach to enable the secure layer.  They use something
often called as the &ldquo;TLS upgrade&rdquo; method. This method is quite tricky but it
is more flexible. The idea is to extend the application protocol to
have a &ldquo;STARTTLS&rdquo; request, whose purpose it to start the TLS
protocols just after the client requests it.  This approach
does not require any extra port to be reserved.
There is even an extension to HTTP protocol to support 
this method [<a class="ref" href="#RFC2817">RFC2817</a>].
</p>
<p>The tricky part, in this method, is that the &ldquo;STARTTLS&rdquo; request is
sent in the clear, thus is vulnerable to modifications.  A typical
attack is to modify the messages in a way that the client is fooled
and thinks that the server does not have the &ldquo;STARTTLS&rdquo; capability.
See a typical conversation of a hypothetical protocol:
</p>
<blockquote class="quotation">
<p>(client connects to the server)
</p>
<p>CLIENT: HELLO I&rsquo;M MR. XXX
</p>
<p>SERVER: NICE TO MEET YOU XXX
</p>
<p>CLIENT: PLEASE START TLS
</p>
<p>SERVER: OK
</p>
<p>*** TLS STARTS
</p>
<p>CLIENT: HERE ARE SOME CONFIDENTIAL DATA
</p></blockquote>

<p>And an example of a conversation where someone is acting
in between:
</p>
<blockquote class="quotation">
<p>(client connects to the server)
</p>
<p>CLIENT: HELLO I&rsquo;M MR. XXX
</p>
<p>SERVER: NICE TO MEET YOU XXX
</p>
<p>CLIENT: PLEASE START TLS
</p>
<p>(here someone inserts this message)
</p>
<p>SERVER: SORRY I DON&rsquo;T HAVE THIS CAPABILITY
</p>
<p>CLIENT: HERE ARE SOME CONFIDENTIAL DATA
</p></blockquote>

<p>As you can see above the client was fooled, and was na&iuml;ve enough to
send the confidential data in the clear, despite the server telling the
client that it does not support &ldquo;STARTTLS&rdquo;.
</p>
<p>How do we avoid the above attack? As you may have already noticed this
situation is easy to avoid.  The client has to ask the user before it
connects whether the user requests <abbr class="acronym">TLS</abbr> or not.  If the user
answered that he certainly wants the secure layer the last
conversation should be:
</p>
<blockquote class="quotation">
<p>(client connects to the server)
</p>
<p>CLIENT: HELLO I&rsquo;M MR. XXX
</p>
<p>SERVER: NICE TO MEET YOU XXX
</p>
<p>CLIENT: PLEASE START TLS
</p>
<p>(here someone inserts this message)
</p>
<p>SERVER: SORRY I DON&rsquo;T HAVE THIS CAPABILITY
</p>
<p>CLIENT: BYE
</p>
<p>(the client notifies the user that the secure connection was not possible)
</p></blockquote>

<p>This method, if implemented properly, is far better than the
traditional method, and the security properties remain the same, since
only denial of service is possible. The benefit is that the server may
request additional data before the <abbr class="acronym">TLS</abbr> Handshake protocol
starts, in order to send the correct certificate, use the correct
password file, or anything else!
</p>
<hr>
</div>
</div>
<div class="section-level-extent" id="On-SSL-2-and-older-protocols">
<div class="nav-panel">
<p>
Previous: <a href="#How-to-use-TLS-in-application-protocols" accesskey="p" rel="prev">How to use <abbr class="acronym">TLS</abbr> in application protocols</a>, Up: <a href="#Introduction-to-TLS" accesskey="u" rel="up">Introduction to <abbr class="acronym">TLS</abbr> and <abbr class="acronym">DTLS</abbr></a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="On-SSL-2-and-older-protocols-1"><span>3.8 On SSL 2 and older protocols<a class="copiable-link" href="#On-SSL-2-and-older-protocols-1"> &para;</a></span></h3>
<a class="index-entry-id" id="index-SSL-2"></a>

<p>One of the initial decisions in the <abbr class="acronym">GnuTLS</abbr> development was
to implement the known security protocols for the transport layer.
Initially <abbr class="acronym">TLS</abbr> 1.0 was implemented since it was the latest at
that time, and was considered to be the most advanced in security
properties.  Later the <abbr class="acronym">SSL</abbr> 3.0 protocol was implemented
since it is still the only protocol supported by several servers and
there are no serious security vulnerabilities known.
</p>
<p>One question that may arise is why we didn&rsquo;t implement <abbr class="acronym">SSL</abbr>
2.0 in the library.  There are several reasons, most important being
that it has serious security flaws, unacceptable for a modern security
library.  Other than that, this protocol is barely used by anyone
these days since it has been deprecated since 1996.  The security
problems in <abbr class="acronym">SSL</abbr> 2.0 include:
</p>
<ul class="itemize mark-bullet">
<li>Message integrity compromised.
The <abbr class="acronym">SSLv2</abbr> message authentication uses the MD5 function, and
is insecure.

</li><li>Man-in-the-middle attack.
There is no protection of the handshake in <abbr class="acronym">SSLv2</abbr>, which
permits a man-in-the-middle attack.

</li><li>Truncation attack.
<abbr class="acronym">SSLv2</abbr> relies on TCP FIN to close the session, so the
attacker can forge a TCP FIN, and the peer cannot tell if it was a
legitimate end of data or not.

</li><li>Weak message integrity for export ciphers.
The cryptographic keys in <abbr class="acronym">SSLv2</abbr> are used for both message
authentication and encryption, so if weak encryption schemes are
negotiated (say 40-bit keys) the message authentication code uses the
same weak key, which isn&rsquo;t necessary.

</li></ul>

<a class="index-entry-id" id="index-PCT"></a>
<p>Other protocols such as Microsoft&rsquo;s <abbr class="acronym">PCT</abbr> 1 and <abbr class="acronym">PCT</abbr>
2 were not implemented because they were also abandoned and deprecated
by <abbr class="acronym">SSL</abbr> 3.0 and later <abbr class="acronym">TLS</abbr> 1.0.
</p>


<hr>
</div>
</div>
<div class="chapter-level-extent" id="Authentication-methods">
<div class="nav-panel">
<p>
Next: <a href="#Hardware-security-modules-and-abstract-key-types" accesskey="n" rel="next">Abstract key types and Hardware security modules</a>, Previous: <a href="#Introduction-to-TLS" accesskey="p" rel="prev">Introduction to <abbr class="acronym">TLS</abbr> and <abbr class="acronym">DTLS</abbr></a>, Up: <a href="#Top" accesskey="u" rel="up">GnuTLS</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h2 class="chapter" id="Authentication-methods-1"><span>4 Authentication methods<a class="copiable-link" href="#Authentication-methods-1"> &para;</a></span></h2>
<a class="index-entry-id" id="index-authentication-methods"></a>

<p>The initial key exchange of the TLS protocol performs authentication
of the peers. In typical scenarios the server is authenticated to
the client, and optionally the client to the server.
</p>
<p>While many associate TLS with X.509 certificates and public key
authentication, the protocol supports various authentication methods,
including pre-shared keys, and passwords. In this chapter a description
of the existing authentication methods is provided, as well as some
guidance on which use-cases each method can be used at.
</p>

<ul class="mini-toc">
<li><a href="#Certificate-authentication" accesskey="1">Certificate authentication</a></li>
<li><a href="#More-on-certificate-authentication" accesskey="2">More on certificate authentication</a></li>
<li><a href="#Shared_002dkey-and-anonymous-authentication" accesskey="3">Shared-key and anonymous authentication</a></li>
<li><a href="#Selecting-an-appropriate-authentication-method" accesskey="4">Selecting an appropriate authentication method</a></li>
</ul>
<hr>
<div class="section-level-extent" id="Certificate-authentication">
<div class="nav-panel">
<p>
Next: <a href="#More-on-certificate-authentication" accesskey="n" rel="next">More on certificate authentication</a>, Up: <a href="#Authentication-methods" accesskey="u" rel="up">Authentication methods</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Certificate-authentication-1"><span>4.1 Certificate authentication<a class="copiable-link" href="#Certificate-authentication-1"> &para;</a></span></h3>
<a class="index-entry-id" id="index-certificate-authentication"></a>

<p>The most known authentication method of <abbr class="acronym">TLS</abbr> are certificates.
The PKIX [<a class="ref" href="#PKIX">PKIX</a>] public key infrastructure is daily used by anyone
using a browser today. <abbr class="acronym">GnuTLS</abbr> provides a simple API to 
verify the <abbr class="acronym">X.509</abbr> certificates as in [<a class="ref" href="#PKIX">PKIX</a>].
</p>
<p>The key exchange algorithms supported by certificate authentication are
shown in <a class="ref" href="#tab_003akey_002dexchange">Table 4.1</a>.
</p>
<div class="float" id="tab_003akey_002dexchange">
<table class="multitable">
<thead><tr><th width="20%">Key exchange</th><th width="70%">Description</th></tr></thead>
<tbody><tr><td width="20%">RSA</td><td width="70%">The RSA algorithm is used to encrypt a key and send it to the peer.
The certificate must allow the key to be used for encryption.</td></tr>
<tr><td width="20%">DHE_RSA</td><td width="70%">The RSA algorithm is used to sign ephemeral Diffie-Hellman parameters
which are sent to the peer. The key in the certificate must allow the
key to be used for signing. Note that key exchange algorithms which
use ephemeral Diffie-Hellman parameters, offer perfect forward
secrecy. That means that even if the private key used for signing is
compromised, it cannot be used to reveal past session data.</td></tr>
<tr><td width="20%">ECDHE_RSA</td><td width="70%">The RSA algorithm is used to sign ephemeral elliptic curve Diffie-Hellman 
parameters which are sent to the peer. The key in the certificate must allow 
the key to be used for signing. It also offers perfect forward
secrecy. That means that even if the private key used for signing is
compromised, it cannot be used to reveal past session data.</td></tr>
<tr><td width="20%">DHE_DSS</td><td width="70%">The DSA algorithm is used to sign ephemeral Diffie-Hellman parameters
which are sent to the peer. The certificate must contain DSA
parameters to use this key exchange algorithm. DSA is the algorithm
of the Digital Signature Standard (DSS).</td></tr>
<tr><td width="20%">ECDHE_ECDSA</td><td width="70%">The Elliptic curve DSA algorithm is used to sign ephemeral elliptic
curve Diffie-Hellman parameters which are sent to the peer. The 
certificate must contain ECDSA parameters (i.e., EC and marked for signing) 
to use this key exchange algorithm.</td></tr>
</tbody>
</table>
<div class="caption"><p><strong class="strong">Table 4.1: </strong>Supported key exchange algorithms.</p></div></div>

<ul class="mini-toc">
<li><a href="#X_002e509-certificates" accesskey="1"><abbr class="acronym">X.509</abbr> certificates</a></li>
<li><a href="#OpenPGP-certificates" accesskey="2"><abbr class="acronym">OpenPGP</abbr> certificates</a></li>
<li><a href="#Raw-public_002dkeys" accesskey="3">Raw public-keys</a></li>
<li><a href="#Advanced-certificate-verification" accesskey="4">Advanced certificate verification</a></li>
<li><a href="#Digital-signatures" accesskey="5">Digital signatures</a></li>
</ul>
<hr>
<div class="subsection-level-extent" id="X_002e509-certificates">
<div class="nav-panel">
<p>
Next: <a href="#OpenPGP-certificates" accesskey="n" rel="next"><abbr class="acronym">OpenPGP</abbr> certificates</a>, Up: <a href="#Certificate-authentication" accesskey="u" rel="up">Certificate authentication</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="X_002e509-certificates-1"><span>4.1.1 <abbr class="acronym">X.509</abbr> certificates<a class="copiable-link" href="#X_002e509-certificates-1"> &para;</a></span></h4>
<a class="index-entry-id" id="index-X_002e509-certificates"></a>

<p>The <abbr class="acronym">X.509</abbr> protocols rely on a hierarchical trust model. In
this trust model Certification Authorities (CAs) are used to certify
entities.  Usually more than one certification authorities exist, and
certification authorities may certify other authorities to issue
certificates as well, following a hierarchical model.
</p>
<div class="float" id="fig_002dx509">
<img class="image" src="gnutls-x509.png" alt="gnutls-x509">
<div class="caption"><p><strong class="strong">Figure 4.1: </strong>An example of the X.509 hierarchical trust model.</p></div></div>
<p>One needs to trust one or more CAs for his secure communications. In
that case only the certificates issued by the trusted authorities are
acceptable.  The framework is illustrated on <a class="ref" href="#fig_002dx509">Figure 4.1</a>.
</p>

<ul class="mini-toc">
<li><a href="#X_002e509-certificate-structure" accesskey="1"><abbr class="acronym">X.509</abbr> certificate structure</a></li>
<li><a href="#Importing-an-X_002e509-certificate" accesskey="2">Importing an X.509 certificate</a></li>
<li><a href="#X_002e509-certificate-names" accesskey="3">X.509 certificate names</a></li>
<li><a href="#X_002e509-distinguished-names" accesskey="4">X.509 distinguished names</a></li>
<li><a href="#X_002e509-extensions" accesskey="5">X.509 extensions</a></li>
<li><a href="#X_002e509-public-and-private-keys" accesskey="6">Accessing public and private keys</a></li>
<li><a href="#Verifying-X_002e509-certificate-paths" accesskey="7">Verifying <abbr class="acronym">X.509</abbr> certificate paths</a></li>
<li><a href="#Verifying-a-certificate-in-the-context-of-TLS-session" accesskey="8">Verifying a certificate in the context of TLS session</a></li>
<li><a href="#Verification-using-PKCS11" accesskey="9">Verifying a certificate using PKCS #11</a></li>
</ul>
<hr>
<div class="subsubsection-level-extent" id="X_002e509-certificate-structure">
<div class="nav-panel">
<p>
Next: <a href="#Importing-an-X_002e509-certificate" accesskey="n" rel="next">Importing an X.509 certificate</a>, Up: <a href="#X_002e509-certificates" accesskey="u" rel="up"><abbr class="acronym">X.509</abbr> certificates</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsubsection" id="X_002e509-certificate-structure-1"><span>4.1.1.1 <abbr class="acronym">X.509</abbr> certificate structure<a class="copiable-link" href="#X_002e509-certificate-structure-1"> &para;</a></span></h4>

<p>An <abbr class="acronym">X.509</abbr> certificate usually contains information about the
certificate holder, the signer, a unique serial number, expiration
dates and some other fields [<a class="ref" href="#PKIX">PKIX</a>] as shown in <a class="ref" href="#tab_003ax509">Table 4.2</a>.
</p>
<div class="float" id="tab_003ax509">
<table class="multitable">
<thead><tr><th width="20%">Field</th><th width="70%">Description</th></tr></thead>
<tbody><tr><td width="20%">version</td><td width="70%">The field that indicates the version of the certificate.</td></tr>
<tr><td width="20%">serialNumber</td><td width="70%">This field holds a unique serial number per certificate.</td></tr>
<tr><td width="20%">signature</td><td width="70%">The issuing authority&rsquo;s signature.</td></tr>
<tr><td width="20%">issuer</td><td width="70%">Holds the issuer&rsquo;s distinguished name.</td></tr>
<tr><td width="20%">validity</td><td width="70%">The activation and expiration dates.</td></tr>
<tr><td width="20%">subject</td><td width="70%">The subject&rsquo;s distinguished name of the certificate.</td></tr>
<tr><td width="20%">extensions</td><td width="70%">The extensions are fields only present in version 3 certificates.</td></tr>
</tbody>
</table>
<div class="caption"><p><strong class="strong">Table 4.2: </strong>X.509 certificate fields.</p></div></div>
<p>The certificate&rsquo;s <em class="emph">subject or issuer name</em> is not just a single
string.  It is a Distinguished name and in the <abbr class="acronym">ASN.1</abbr>
notation is a sequence of several object identifiers with their corresponding
values. Some of available OIDs to be used in an <abbr class="acronym">X.509</abbr>
distinguished name are defined in <samp class="file">gnutls/x509.h</samp>.
</p>
<p>The <em class="emph">Version</em> field in a certificate has values either 1 or 3 for
version 3 certificates.  Version 1 certificates do not support the
extensions field so it is not possible to distinguish a CA from a
person, thus their usage should be avoided.
</p>
<p>The <em class="emph">validity</em> dates are there to indicate the date that the
specific certificate was activated and the date the certificate&rsquo;s key
would be considered invalid.
</p>

<p>In <abbr class="acronym">GnuTLS</abbr> the <abbr class="acronym">X.509</abbr> certificate structures are
handled using the <code class="code">gnutls_x509_crt_t</code> type and the corresponding
private keys with the <code class="code">gnutls_x509_privkey_t</code> type.  All the
available functions for <abbr class="acronym">X.509</abbr> certificate handling have
their prototypes in <samp class="file">gnutls/x509.h</samp>. An example program to
demonstrate the <abbr class="acronym">X.509</abbr> parsing capabilities can be found in
<a class="ref" href="#ex_002dx509_002dinfo">ex-x509-info</a>.
</p>
<hr>
</div>
<div class="subsubsection-level-extent" id="Importing-an-X_002e509-certificate">
<div class="nav-panel">
<p>
Next: <a href="#X_002e509-certificate-names" accesskey="n" rel="next">X.509 certificate names</a>, Previous: <a href="#X_002e509-certificate-structure" accesskey="p" rel="prev"><abbr class="acronym">X.509</abbr> certificate structure</a>, Up: <a href="#X_002e509-certificates" accesskey="u" rel="up"><abbr class="acronym">X.509</abbr> certificates</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsubsection" id="Importing-an-X_002e509-certificate-1"><span>4.1.1.2 Importing an X.509 certificate<a class="copiable-link" href="#Importing-an-X_002e509-certificate-1"> &para;</a></span></h4>

<p>The certificate structure should be initialized using <a class="ref" href="#gnutls_005fx509_005fcrt_005finit">gnutls_x509_crt_init</a>, and 
a certificate structure can be imported using <a class="ref" href="#gnutls_005fx509_005fcrt_005fimport">gnutls_x509_crt_import</a>. 
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrt_005finit">gnutls_x509_crt_init</a> (gnutls_x509_crt_t * <var class="var">cert</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrt_005fimport">gnutls_x509_crt_import</a> (gnutls_x509_crt_t <var class="var">cert</var>, const gnutls_datum_t * <var class="var">data</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fx509_005fcrt_005fdeinit">gnutls_x509_crt_deinit</a> (gnutls_x509_crt_t <var class="var">cert</var>)</code></dt>
</dl>

<p>In several functions an array of certificates is required. To assist in initialization
and import the following two functions are provided.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrt_005flist_005fimport">gnutls_x509_crt_list_import</a> (gnutls_x509_crt_t * <var class="var">certs</var>, unsigned int * <var class="var">cert_max</var>, const gnutls_datum_t * <var class="var">data</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, unsigned int <var class="var">flags</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrt_005flist_005fimport2">gnutls_x509_crt_list_import2</a> (gnutls_x509_crt_t ** <var class="var">certs</var>, unsigned int * <var class="var">size</var>, const gnutls_datum_t * <var class="var">data</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, unsigned int <var class="var">flags</var>)</code></dt>
</dl>

<p>In all cases after use a certificate must be deinitialized using <a class="ref" href="#gnutls_005fx509_005fcrt_005fdeinit">gnutls_x509_crt_deinit</a>.
Note that although the functions above apply to <code class="code">gnutls_x509_crt_t</code> structure, similar functions
exist for the CRL structure <code class="code">gnutls_x509_crl_t</code>.
</p>
<hr>
</div>
<div class="subsubsection-level-extent" id="X_002e509-certificate-names">
<div class="nav-panel">
<p>
Next: <a href="#X_002e509-distinguished-names" accesskey="n" rel="next">X.509 distinguished names</a>, Previous: <a href="#Importing-an-X_002e509-certificate" accesskey="p" rel="prev">Importing an X.509 certificate</a>, Up: <a href="#X_002e509-certificates" accesskey="u" rel="up"><abbr class="acronym">X.509</abbr> certificates</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsubsection" id="X_002e509-certificate-names-1"><span>4.1.1.3 X.509 certificate names<a class="copiable-link" href="#X_002e509-certificate-names-1"> &para;</a></span></h4>
<a class="index-entry-id" id="index-X_002e509-certificate-name"></a>

<p>X.509 certificates allow for multiple names and types of names to be specified.
CA certificates often rely on X.509 distinguished names (see <a class="ref" href="#X_002e509-distinguished-names">X.509 distinguished names</a>)
for unique identification, while end-user and server certificates rely on the
&rsquo;subject alternative names&rsquo;. The subject alternative names provide a typed name, e.g.,
a DNS name, or an email address, which identifies the owner of the certificate.
The following functions provide access to that names.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrt_005fget_005fsubject_005falt_005fname2">gnutls_x509_crt_get_subject_alt_name2</a> (gnutls_x509_crt_t <var class="var">cert</var>, unsigned int <var class="var">seq</var>, void * <var class="var">san</var>, size_t * <var class="var">san_size</var>, unsigned int * <var class="var">san_type</var>, unsigned int * <var class="var">critical</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrt_005fset_005fsubject_005falt_005fname">gnutls_x509_crt_set_subject_alt_name</a> (gnutls_x509_crt_t <var class="var">crt</var>, gnutls_x509_subject_alt_name_t <var class="var">type</var>, const void * <var class="var">data</var>, unsigned int <var class="var">data_size</var>, unsigned int <var class="var">flags</var>)</code></dt>
</dl>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fsubject_005falt_005fnames_005finit">gnutls_subject_alt_names_init</a> (gnutls_subject_alt_names_t * <var class="var">sans</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fsubject_005falt_005fnames_005fget">gnutls_subject_alt_names_get</a> (gnutls_subject_alt_names_t <var class="var">sans</var>, unsigned int <var class="var">seq</var>, unsigned int * <var class="var">san_type</var>, gnutls_datum_t * <var class="var">san</var>, gnutls_datum_t * <var class="var">othername_oid</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fsubject_005falt_005fnames_005fset">gnutls_subject_alt_names_set</a> (gnutls_subject_alt_names_t <var class="var">sans</var>, unsigned int <var class="var">san_type</var>, const gnutls_datum_t * <var class="var">san</var>, const char * <var class="var">othername_oid</var>)</code></dt>
</dl>

<p>Note however, that server certificates often used the Common Name (CN), part of the
certificate DistinguishedName to place a single DNS address. That practice is discouraged
(see [<a class="ref" href="#RFC6125">RFC6125</a>]), because only a single address can be specified, and the CN field is
free-form making matching ambiguous.
</p>
<hr>
</div>
<div class="subsubsection-level-extent" id="X_002e509-distinguished-names">
<div class="nav-panel">
<p>
Next: <a href="#X_002e509-extensions" accesskey="n" rel="next">X.509 extensions</a>, Previous: <a href="#X_002e509-certificate-names" accesskey="p" rel="prev">X.509 certificate names</a>, Up: <a href="#X_002e509-certificates" accesskey="u" rel="up"><abbr class="acronym">X.509</abbr> certificates</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsubsection" id="X_002e509-distinguished-names-1"><span>4.1.1.4 X.509 distinguished names<a class="copiable-link" href="#X_002e509-distinguished-names-1"> &para;</a></span></h4>
<a class="index-entry-id" id="index-X_002e509-distinguished-name"></a>

<p>The &ldquo;subject&rdquo; of an X.509 certificate is not described by
a single name, but rather with a distinguished name. This in
X.509 terminology is a list of strings each associated an object
identifier. To make things simple GnuTLS provides <a class="ref" href="#gnutls_005fx509_005fcrt_005fget_005fdn2">gnutls_x509_crt_get_dn2</a>
which follows the rules in [<a class="ref" href="#RFC4514">RFC4514</a>] and returns a single
string. Access to each string by individual object identifiers
can be accessed using <a class="ref" href="#gnutls_005fx509_005fcrt_005fget_005fdn_005fby_005foid">gnutls_x509_crt_get_dn_by_oid</a>.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fdn2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_dn2</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, gnutls_datum_t * <var class="var">dn</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fdn2"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">dn</var>: a pointer to a structure to hold the name; must be freed using <code class="code">gnutls_free()</code> 
</p>
<p>This function will allocate buffer and copy the name of the Certificate.
The name will be in the form &quot;C=xxxx,O=yyyy,CN=zzzz&quot; as
described in RFC4514. The output string will be ASCII or UTF-8
encoded, depending on the certificate data.
</p>
<p>This function does not output a fully RFC4514 compliant string, if
that is required see <code class="code">gnutls_x509_crt_get_dn3()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.1.10
</p></dd></dl>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrt_005fget_005fdn">gnutls_x509_crt_get_dn</a> (gnutls_x509_crt_t <var class="var">cert</var>, char * <var class="var">buf</var>, size_t * <var class="var">buf_size</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrt_005fget_005fdn_005fby_005foid">gnutls_x509_crt_get_dn_by_oid</a> (gnutls_x509_crt_t <var class="var">cert</var>, const char * <var class="var">oid</var>, unsigned <var class="var">indx</var>, unsigned int <var class="var">raw_flag</var>, void * <var class="var">buf</var>, size_t * <var class="var">buf_size</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrt_005fget_005fdn_005foid">gnutls_x509_crt_get_dn_oid</a> (gnutls_x509_crt_t <var class="var">cert</var>, unsigned <var class="var">indx</var>, void * <var class="var">oid</var>, size_t * <var class="var">oid_size</var>)</code></dt>
</dl>

<p>Similar functions exist to access the distinguished name
of the issuer of the certificate.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn">gnutls_x509_crt_get_issuer_dn</a> (gnutls_x509_crt_t <var class="var">cert</var>, char * <var class="var">buf</var>, size_t * <var class="var">buf_size</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn2">gnutls_x509_crt_get_issuer_dn2</a> (gnutls_x509_crt_t <var class="var">cert</var>, gnutls_datum_t * <var class="var">dn</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn_005fby_005foid">gnutls_x509_crt_get_issuer_dn_by_oid</a> (gnutls_x509_crt_t <var class="var">cert</var>, const char * <var class="var">oid</var>, unsigned <var class="var">indx</var>, unsigned int <var class="var">raw_flag</var>, void * <var class="var">buf</var>, size_t * <var class="var">buf_size</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn_005foid">gnutls_x509_crt_get_issuer_dn_oid</a> (gnutls_x509_crt_t <var class="var">cert</var>, unsigned <var class="var">indx</var>, void * <var class="var">oid</var>, size_t * <var class="var">oid_size</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrt_005fget_005fissuer">gnutls_x509_crt_get_issuer</a> (gnutls_x509_crt_t <var class="var">cert</var>, gnutls_x509_dn_t * <var class="var">dn</var>)</code></dt>
</dl>

<p>The more powerful <a class="ref" href="#gnutls_005fx509_005fcrt_005fget_005fsubject">gnutls_x509_crt_get_subject</a> and 
<a class="ref" href="#gnutls_005fx509_005fdn_005fget_005frdn_005fava">gnutls_x509_dn_get_rdn_ava</a> provide efficient but low-level access
to the contents of the distinguished name structure.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrt_005fget_005fsubject">gnutls_x509_crt_get_subject</a> (gnutls_x509_crt_t <var class="var">cert</var>, gnutls_x509_dn_t * <var class="var">dn</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrt_005fget_005fissuer">gnutls_x509_crt_get_issuer</a> (gnutls_x509_crt_t <var class="var">cert</var>, gnutls_x509_dn_t * <var class="var">dn</var>)</code></dt>
</dl>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fdn_005fget_005frdn_005fava"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_dn_get_rdn_ava</strong> <code class="def-code-arguments">(gnutls_x509_dn_t <var class="var">dn</var>, int <var class="var">irdn</var>, int <var class="var">iava</var>, gnutls_x509_ava_st * <var class="var">ava</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fdn_005fget_005frdn_005fava"> &para;</a></span></dt>
<dd><p><var class="var">dn</var>: a pointer to DN
</p>
<p><var class="var">irdn</var>: index of RDN
</p>
<p><var class="var">iava</var>: index of AVA.
</p>
<p><var class="var">ava</var>: Pointer to structure which will hold output information.
</p>
<p>Get pointers to data within the DN. The format of the  <code class="code">ava</code> structure
is shown below.
</p>
<p>struct gnutls_x509_ava_st {
gnutls_datum_t oid;
gnutls_datum_t value;
unsigned long value_tag;
};
</p>
<p>The X.509 distinguished name is a sequence of sequences of strings
and this is what the  <code class="code">irdn</code> and  <code class="code">iava</code> indexes model.
</p>
<p>Note that  <code class="code">ava</code> will contain pointers into the  <code class="code">dn</code> structure which
in turns points to the original certificate. Thus you should not
modify any data or deallocate any of those.
</p>
<p>This is a low-level function that requires the caller to do the
value conversions when necessary (e.g. from UCS-2).
</p>
<p><strong class="strong">Returns:</strong> Returns 0 on success, or an error code.
</p></dd></dl>

<hr>
</div>
<div class="subsubsection-level-extent" id="X_002e509-extensions">
<div class="nav-panel">
<p>
Next: <a href="#X_002e509-public-and-private-keys" accesskey="n" rel="next">Accessing public and private keys</a>, Previous: <a href="#X_002e509-distinguished-names" accesskey="p" rel="prev">X.509 distinguished names</a>, Up: <a href="#X_002e509-certificates" accesskey="u" rel="up"><abbr class="acronym">X.509</abbr> certificates</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsubsection" id="X_002e509-extensions-1"><span>4.1.1.5 X.509 extensions<a class="copiable-link" href="#X_002e509-extensions-1"> &para;</a></span></h4>
<a class="index-entry-id" id="index-X_002e509-extensions"></a>

<p>X.509 version 3 certificates include a list of extensions that can
be used to obtain additional information on the subject or the issuer
of the certificate. Those may be e-mail addresses, flags that indicate whether the
belongs to a CA etc.  All the supported <abbr class="acronym">X.509</abbr> version 3
extensions are shown in <a class="ref" href="#tab_003ax509_002dext">Table 4.3</a>.
</p>
<p>The certificate extensions access is split into two parts. The first
requires to retrieve the extension, and the second is the parsing part.
</p>
<p>To enumerate and retrieve the DER-encoded extension data available in a certificate the following
two functions are available.
</p><dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrt_005fget_005fextension_005finfo">gnutls_x509_crt_get_extension_info</a> (gnutls_x509_crt_t <var class="var">cert</var>, unsigned <var class="var">indx</var>, void * <var class="var">oid</var>, size_t * <var class="var">oid_size</var>, unsigned int * <var class="var">critical</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrt_005fget_005fextension_005fdata2">gnutls_x509_crt_get_extension_data2</a> (gnutls_x509_crt_t <var class="var">cert</var>, unsigned <var class="var">indx</var>, gnutls_datum_t * <var class="var">data</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrt_005fget_005fextension_005fby_005foid2">gnutls_x509_crt_get_extension_by_oid2</a> (gnutls_x509_crt_t <var class="var">cert</var>, const char * <var class="var">oid</var>, unsigned <var class="var">indx</var>, gnutls_datum_t * <var class="var">output</var>, unsigned int * <var class="var">critical</var>)</code></dt>
</dl>

<p>After a supported DER-encoded extension is retrieved it can be parsed using the APIs in <code class="code">x509-ext.h</code>.
Complex extensions may require initializing an intermediate structure that holds the
parsed extension data. Examples of simple parsing functions are shown below.
</p><dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fext_005fimport_005fbasic_005fconstraints">gnutls_x509_ext_import_basic_constraints</a> (const gnutls_datum_t * <var class="var">ext</var>, unsigned int * <var class="var">ca</var>, int * <var class="var">pathlen</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fext_005fexport_005fbasic_005fconstraints">gnutls_x509_ext_export_basic_constraints</a> (unsigned int <var class="var">ca</var>, int <var class="var">pathlen</var>, gnutls_datum_t * <var class="var">ext</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fext_005fimport_005fkey_005fusage">gnutls_x509_ext_import_key_usage</a> (const gnutls_datum_t * <var class="var">ext</var>, unsigned int * <var class="var">key_usage</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fext_005fexport_005fkey_005fusage">gnutls_x509_ext_export_key_usage</a> (unsigned int <var class="var">usage</var>, gnutls_datum_t * <var class="var">ext</var>)</code></dt>
</dl>

<p>More complex extensions, such as Name Constraints, require an intermediate structure, in that
case <code class="code">gnutls_x509_name_constraints_t</code> to be initialized in order to store the parsed
extension data. 
</p><dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fext_005fimport_005fname_005fconstraints">gnutls_x509_ext_import_name_constraints</a> (const gnutls_datum_t * <var class="var">ext</var>, gnutls_x509_name_constraints_t <var class="var">nc</var>, unsigned int <var class="var">flags</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fext_005fexport_005fname_005fconstraints">gnutls_x509_ext_export_name_constraints</a> (gnutls_x509_name_constraints_t <var class="var">nc</var>, gnutls_datum_t * <var class="var">ext</var>)</code></dt>
</dl>

<p>After the name constraints are extracted in the structure, the following functions
can be used to access them.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fname_005fconstraints_005fget_005fpermitted">gnutls_x509_name_constraints_get_permitted</a> (gnutls_x509_name_constraints_t <var class="var">nc</var>, unsigned <var class="var">idx</var>, unsigned * <var class="var">type</var>, gnutls_datum_t * <var class="var">name</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fname_005fconstraints_005fget_005fexcluded">gnutls_x509_name_constraints_get_excluded</a> (gnutls_x509_name_constraints_t <var class="var">nc</var>, unsigned <var class="var">idx</var>, unsigned * <var class="var">type</var>, gnutls_datum_t * <var class="var">name</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fname_005fconstraints_005fadd_005fpermitted">gnutls_x509_name_constraints_add_permitted</a> (gnutls_x509_name_constraints_t <var class="var">nc</var>, gnutls_x509_subject_alt_name_t <var class="var">type</var>, const gnutls_datum_t * <var class="var">name</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fname_005fconstraints_005fadd_005fexcluded">gnutls_x509_name_constraints_add_excluded</a> (gnutls_x509_name_constraints_t <var class="var">nc</var>, gnutls_x509_subject_alt_name_t <var class="var">type</var>, const gnutls_datum_t * <var class="var">name</var>)</code></dt>
</dl>
<dl class="table">
<dt><code class="code"><var class="var">unsigned</var> <a class="ref" href="#gnutls_005fx509_005fname_005fconstraints_005fcheck">gnutls_x509_name_constraints_check</a> (gnutls_x509_name_constraints_t <var class="var">nc</var>, gnutls_x509_subject_alt_name_t <var class="var">type</var>, const gnutls_datum_t * <var class="var">name</var>)</code></dt>
<dt><code class="code"><var class="var">unsigned</var> <a class="ref" href="#gnutls_005fx509_005fname_005fconstraints_005fcheck_005fcrt">gnutls_x509_name_constraints_check_crt</a> (gnutls_x509_name_constraints_t <var class="var">nc</var>, gnutls_x509_subject_alt_name_t <var class="var">type</var>, gnutls_x509_crt_t <var class="var">cert</var>)</code></dt>
</dl>

<p>Other utility functions are listed below.
</p><dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fname_005fconstraints_005finit">gnutls_x509_name_constraints_init</a> (gnutls_x509_name_constraints_t * <var class="var">nc</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fx509_005fname_005fconstraints_005fdeinit">gnutls_x509_name_constraints_deinit</a> (gnutls_x509_name_constraints_t <var class="var">nc</var>)</code></dt>
</dl>

<p>Similar functions exist for all of the other supported extensions, listed in <a class="ref" href="#tab_003ax509_002dext">Table 4.3</a>.
</p>
<div class="float" id="tab_003ax509_002dext">
<table class="multitable">
<thead><tr><th width="30%">Extension</th><th width="20%">OID</th><th width="40%">Description</th></tr></thead>
<tbody><tr><td width="30%">Subject key id</td><td width="20%">2.5.29.14</td><td width="40%">An identifier of the key of the subject.</td></tr>
<tr><td width="30%">Key usage</td><td width="20%">2.5.29.15</td><td width="40%">Constraints the key&rsquo;s usage of the certificate.</td></tr>
<tr><td width="30%">Private key usage period</td><td width="20%">2.5.29.16</td><td width="40%">Constraints the validity time of the private key.</td></tr>
<tr><td width="30%">Subject alternative name</td><td width="20%">2.5.29.17</td><td width="40%">Alternative names to subject&rsquo;s distinguished name.</td></tr>
<tr><td width="30%">Issuer alternative name</td><td width="20%">2.5.29.18</td><td width="40%">Alternative names to the issuer&rsquo;s distinguished name.</td></tr>
<tr><td width="30%">Basic constraints</td><td width="20%">2.5.29.19</td><td width="40%">Indicates whether this is a CA certificate or not, and specify the
maximum path lengths of certificate chains.</td></tr>
<tr><td width="30%">Name constraints</td><td width="20%">2.5.29.30</td><td width="40%">A field in CA certificates that restricts the scope of the name of
issued certificates.</td></tr>
<tr><td width="30%">CRL distribution points</td><td width="20%">2.5.29.31</td><td width="40%">This extension is set by the CA, in order to inform about the
location of issued Certificate Revocation Lists.</td></tr>
<tr><td width="30%">Certificate policy</td><td width="20%">2.5.29.32</td><td width="40%">This extension is set to indicate the certificate policy as object
identifier and may contain a descriptive string or URL.</td></tr>
<tr><td width="30%">Extended key usage</td><td width="20%">2.5.29.54</td><td width="40%">Inhibit any policy extension. Constraints the any policy OID
(<code class="code">GNUTLS_X509_OID_POLICY_ANY</code>) use in the policy extension.</td></tr>
<tr><td width="30%">Authority key identifier</td><td width="20%">2.5.29.35</td><td width="40%">An identifier of the key of the issuer of the certificate. That is
used to distinguish between different keys of the same issuer.</td></tr>
<tr><td width="30%">Extended key usage</td><td width="20%">2.5.29.37</td><td width="40%">Constraints the purpose of the certificate.</td></tr>
<tr><td width="30%">Authority information access</td><td width="20%">1.3.6.1.5.5.7.1.1</td><td width="40%">Information on services by the issuer of the certificate.</td></tr>
<tr><td width="30%">Proxy Certification Information</td><td width="20%">1.3.6.1.5.5.7.1.14</td><td width="40%">Proxy Certificates includes this extension that contains the OID of
the proxy policy language used, and can specify limits on the maximum
lengths of proxy chains.  Proxy Certificates are specified in
[<a class="ref" href="#RFC3820">RFC3820</a>].</td></tr>
</tbody>
</table>
<div class="caption"><p><strong class="strong">Table 4.3: </strong>Supported X.509 certificate extensions.</p></div></div>
<p>Note, that there are also direct APIs to access extensions that may
be simpler to use for non-complex extensions. They are available
in <code class="code">x509.h</code> and some examples are listed below.
</p><dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrt_005fget_005fbasic_005fconstraints">gnutls_x509_crt_get_basic_constraints</a> (gnutls_x509_crt_t <var class="var">cert</var>, unsigned int * <var class="var">critical</var>, unsigned int * <var class="var">ca</var>, int * <var class="var">pathlen</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrt_005fset_005fbasic_005fconstraints">gnutls_x509_crt_set_basic_constraints</a> (gnutls_x509_crt_t <var class="var">crt</var>, unsigned int <var class="var">ca</var>, int <var class="var">pathLenConstraint</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrt_005fget_005fkey_005fusage">gnutls_x509_crt_get_key_usage</a> (gnutls_x509_crt_t <var class="var">cert</var>, unsigned int * <var class="var">key_usage</var>, unsigned int * <var class="var">critical</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrt_005fset_005fkey_005fusage">gnutls_x509_crt_set_key_usage</a> (gnutls_x509_crt_t <var class="var">crt</var>, unsigned int <var class="var">usage</var>)</code></dt>
</dl>


<hr>
</div>
<div class="subsubsection-level-extent" id="X_002e509-public-and-private-keys">
<div class="nav-panel">
<p>
Next: <a href="#Verifying-X_002e509-certificate-paths" accesskey="n" rel="next">Verifying <abbr class="acronym">X.509</abbr> certificate paths</a>, Previous: <a href="#X_002e509-extensions" accesskey="p" rel="prev">X.509 extensions</a>, Up: <a href="#X_002e509-certificates" accesskey="u" rel="up"><abbr class="acronym">X.509</abbr> certificates</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsubsection" id="Accessing-public-and-private-keys"><span>4.1.1.6 Accessing public and private keys<a class="copiable-link" href="#Accessing-public-and-private-keys"> &para;</a></span></h4>

<p>Each X.509 certificate contains a public key that corresponds to a private key. To
get a unique identifier of the public key the <a class="ref" href="#gnutls_005fx509_005fcrt_005fget_005fkey_005fid">gnutls_x509_crt_get_key_id</a>
function is provided. To export the public key or its parameters you may need
to convert the X.509 structure to a <code class="code">gnutls_pubkey_t</code>. See 
<a class="ref" href="#Abstract-public-keys">Public keys</a> for more information.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fkey_005fid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_key_id</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, unsigned int <var class="var">flags</var>, unsigned char * <var class="var">output_data</var>, size_t * <var class="var">output_data_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fkey_005fid"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: Holds the certificate
</p>
<p><var class="var">flags</var>: should be one of the flags from <code class="code">gnutls_keyid_flags_t</code> 
</p>
<p><var class="var">output_data</var>: will contain the key ID
</p>
<p><var class="var">output_data_size</var>: holds the size of output_data (and will be
replaced by the actual size of parameters)
</p>
<p>This function will return a unique ID that depends on the public
key parameters. This ID can be used in checking whether a
certificate corresponds to the given private key.
</p>
<p>If the buffer provided is not long enough to hold the output, then
*output_data_size is updated and GNUTLS_E_SHORT_MEMORY_BUFFER will
be returned.  The output will normally be a SHA-1 hash output,
which is 20 bytes.
</p>
<p><strong class="strong">Returns:</strong> In case of failure a negative error code will be
returned, and 0 on success.
</p></dd></dl>

<p>The private key parameters may be directly accessed by using one of the following functions.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fprivkey_005fget_005fpk_005falgorithm2">gnutls_x509_privkey_get_pk_algorithm2</a> (gnutls_x509_privkey_t <var class="var">key</var>, unsigned int * <var class="var">bits</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fprivkey_005fexport_005frsa_005fraw2">gnutls_x509_privkey_export_rsa_raw2</a> (gnutls_x509_privkey_t <var class="var">key</var>, gnutls_datum_t * <var class="var">m</var>, gnutls_datum_t * <var class="var">e</var>, gnutls_datum_t * <var class="var">d</var>, gnutls_datum_t * <var class="var">p</var>, gnutls_datum_t * <var class="var">q</var>, gnutls_datum_t * <var class="var">u</var>, gnutls_datum_t * <var class="var">e1</var>, gnutls_datum_t * <var class="var">e2</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fprivkey_005fexport_005fecc_005fraw">gnutls_x509_privkey_export_ecc_raw</a> (gnutls_x509_privkey_t <var class="var">key</var>, gnutls_ecc_curve_t * <var class="var">curve</var>, gnutls_datum_t * <var class="var">x</var>, gnutls_datum_t * <var class="var">y</var>, gnutls_datum_t * <var class="var">k</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fprivkey_005fexport_005fdsa_005fraw">gnutls_x509_privkey_export_dsa_raw</a> (gnutls_x509_privkey_t <var class="var">key</var>, gnutls_datum_t * <var class="var">p</var>, gnutls_datum_t * <var class="var">q</var>, gnutls_datum_t * <var class="var">g</var>, gnutls_datum_t * <var class="var">y</var>, gnutls_datum_t * <var class="var">x</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fprivkey_005fget_005fkey_005fid">gnutls_x509_privkey_get_key_id</a> (gnutls_x509_privkey_t <var class="var">key</var>, unsigned int <var class="var">flags</var>, unsigned char * <var class="var">output_data</var>, size_t * <var class="var">output_data_size</var>)</code></dt>
</dl>

<hr>
</div>
<div class="subsubsection-level-extent" id="Verifying-X_002e509-certificate-paths">
<div class="nav-panel">
<p>
Next: <a href="#Verifying-a-certificate-in-the-context-of-TLS-session" accesskey="n" rel="next">Verifying a certificate in the context of TLS session</a>, Previous: <a href="#X_002e509-public-and-private-keys" accesskey="p" rel="prev">Accessing public and private keys</a>, Up: <a href="#X_002e509-certificates" accesskey="u" rel="up"><abbr class="acronym">X.509</abbr> certificates</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsubsection" id="Verifying-X_002e509-certificate-paths-1"><span>4.1.1.7 Verifying <abbr class="acronym">X.509</abbr> certificate paths<a class="copiable-link" href="#Verifying-X_002e509-certificate-paths-1"> &para;</a></span></h4>
<a class="index-entry-id" id="index-verifying-certificate-paths"></a>

<p>Verifying certificate paths is important in <abbr class="acronym">X.509</abbr>
authentication. For this purpose the following functions are
provided.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005ftrust_005flist_005fadd_005fcas"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_trust_list_add_cas</strong> <code class="def-code-arguments">(gnutls_x509_trust_list_t <var class="var">list</var>, const gnutls_x509_crt_t * <var class="var">clist</var>, unsigned <var class="var">clist_size</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005ftrust_005flist_005fadd_005fcas"> &para;</a></span></dt>
<dd><p><var class="var">list</var>: The list
</p>
<p><var class="var">clist</var>: A list of CAs
</p>
<p><var class="var">clist_size</var>: The length of the CA list
</p>
<p><var class="var">flags</var>: flags from <code class="code">gnutls_trust_list_flags_t</code> 
</p>
<p>This function will add the given certificate authorities
to the trusted list. The CAs in  <code class="code">clist</code> must not be deinitialized
during the lifetime of  <code class="code">list</code> .
</p>
<p>If the flag <code class="code">GNUTLS_TL_NO_DUPLICATES</code>  is specified, then
this function will ensure that no duplicates will be
present in the final trust list.
</p>
<p>If the flag <code class="code">GNUTLS_TL_NO_DUPLICATE_KEY</code>  is specified, then
this function will ensure that no certificates with the
same key are present in the final trust list.
</p>
<p>If either <code class="code">GNUTLS_TL_NO_DUPLICATE_KEY</code>  or <code class="code">GNUTLS_TL_NO_DUPLICATES</code> 
are given, <code class="code">gnutls_x509_trust_list_deinit()</code>  must be called with parameter
 <code class="code">all</code> being 1.
</p>
<p><strong class="strong">Returns:</strong> The number of added elements is returned; that includes
duplicate entries.
</p>
<p><strong class="strong">Since:</strong> 3.0.0
</p></dd></dl>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005ftrust_005flist_005fadd_005fnamed_005fcrt"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_trust_list_add_named_crt</strong> <code class="def-code-arguments">(gnutls_x509_trust_list_t <var class="var">list</var>, gnutls_x509_crt_t <var class="var">cert</var>, const void * <var class="var">name</var>, size_t <var class="var">name_size</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005ftrust_005flist_005fadd_005fnamed_005fcrt"> &para;</a></span></dt>
<dd><p><var class="var">list</var>: The list
</p>
<p><var class="var">cert</var>: A certificate
</p>
<p><var class="var">name</var>: An identifier for the certificate
</p>
<p><var class="var">name_size</var>: The size of the identifier
</p>
<p><var class="var">flags</var>: should be 0.
</p>
<p>This function will add the given certificate to the trusted
list and associate it with a name. The certificate will not be
be used for verification with <code class="code">gnutls_x509_trust_list_verify_crt()</code> 
but with <code class="code">gnutls_x509_trust_list_verify_named_crt()</code>  or
<code class="code">gnutls_x509_trust_list_verify_crt2()</code>  - the latter only since
GnuTLS 3.4.0 and if a hostname is provided.
</p>
<p>In principle this function can be used to set individual &quot;server&quot;
certificates that are trusted by the user for that specific server
but for no other purposes.
</p>
<p>The certificate  <code class="code">cert</code> must not be deinitialized during the lifetime
of the  <code class="code">list</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.0.0
</p></dd></dl>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005ftrust_005flist_005fadd_005fcrls"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_trust_list_add_crls</strong> <code class="def-code-arguments">(gnutls_x509_trust_list_t <var class="var">list</var>, const gnutls_x509_crl_t * <var class="var">crl_list</var>, unsigned <var class="var">crl_size</var>, unsigned int <var class="var">flags</var>, unsigned int <var class="var">verification_flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005ftrust_005flist_005fadd_005fcrls"> &para;</a></span></dt>
<dd><p><var class="var">list</var>: The list
</p>
<p><var class="var">crl_list</var>: A list of CRLs
</p>
<p><var class="var">crl_size</var>: The length of the CRL list
</p>
<p><var class="var">flags</var>: flags from <code class="code">gnutls_trust_list_flags_t</code> 
</p>
<p><var class="var">verification_flags</var>: gnutls_certificate_verify_flags if flags specifies GNUTLS_TL_VERIFY_CRL
</p>
<p>This function will add the given certificate revocation lists
to the trusted list. The CRLs in  <code class="code">crl_list</code> must not be deinitialized
during the lifetime of  <code class="code">list</code> .
</p>
<p>This function must be called after <code class="code">gnutls_x509_trust_list_add_cas()</code> 
to allow verifying the CRLs for validity. If the flag <code class="code">GNUTLS_TL_NO_DUPLICATES</code> 
is given, then the final CRL list will not contain duplicate entries.
</p>
<p>If the flag <code class="code">GNUTLS_TL_NO_DUPLICATES</code>  is given, <code class="code">gnutls_x509_trust_list_deinit()</code>  must be
called with parameter  <code class="code">all</code> being 1.
</p>
<p>If flag <code class="code">GNUTLS_TL_VERIFY_CRL</code>  is given the CRLs will be verified before being added,
and if verification fails, they will be skipped.
</p>
<p><strong class="strong">Returns:</strong> The number of added elements is returned; that includes
duplicate entries.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005ftrust_005flist_005fverify_005fcrt"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_trust_list_verify_crt</strong> <code class="def-code-arguments">(gnutls_x509_trust_list_t <var class="var">list</var>, gnutls_x509_crt_t * <var class="var">cert_list</var>, unsigned int <var class="var">cert_list_size</var>, unsigned int <var class="var">flags</var>, unsigned int * <var class="var">voutput</var>, gnutls_verify_output_function <var class="var">func</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005ftrust_005flist_005fverify_005fcrt"> &para;</a></span></dt>
<dd><p><var class="var">list</var>: The list
</p>
<p><var class="var">cert_list</var>: is the certificate list to be verified
</p>
<p><var class="var">cert_list_size</var>: is the certificate list size
</p>
<p><var class="var">flags</var>: Flags that may be used to change the verification algorithm. Use OR of the gnutls_certificate_verify_flags enumerations.
</p>
<p><var class="var">voutput</var>: will hold the certificate verification output.
</p>
<p><var class="var">func</var>: If non-null will be called on each chain element verification with the output.
</p>
<p>This function will try to verify the given certificate and return
its status. The  <code class="code">voutput</code> parameter will hold an OR&rsquo;ed sequence of
<code class="code">gnutls_certificate_status_t</code>  flags.
</p>
<p>The details of the verification are the same as in <code class="code">gnutls_x509_trust_list_verify_crt2()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005ftrust_005flist_005fverify_005fcrt2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_trust_list_verify_crt2</strong> <code class="def-code-arguments">(gnutls_x509_trust_list_t <var class="var">list</var>, gnutls_x509_crt_t * <var class="var">cert_list</var>, unsigned int <var class="var">cert_list_size</var>, gnutls_typed_vdata_st * <var class="var">data</var>, unsigned int <var class="var">elements</var>, unsigned int <var class="var">flags</var>, unsigned int * <var class="var">voutput</var>, gnutls_verify_output_function <var class="var">func</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005ftrust_005flist_005fverify_005fcrt2"> &para;</a></span></dt>
<dd><p><var class="var">list</var>: The list
</p>
<p><var class="var">cert_list</var>: is the certificate list to be verified
</p>
<p><var class="var">cert_list_size</var>: is the certificate list size
</p>
<p><var class="var">data</var>: an array of typed data
</p>
<p><var class="var">elements</var>: the number of data elements
</p>
<p><var class="var">flags</var>: Flags that may be used to change the verification algorithm. Use OR of the gnutls_certificate_verify_flags enumerations.
</p>
<p><var class="var">voutput</var>: will hold the certificate verification output.
</p>
<p><var class="var">func</var>: If non-null will be called on each chain element verification with the output.
</p>
<p>This function will attempt to verify the given certificate chain and return
its status. The  <code class="code">voutput</code> parameter will hold an OR&rsquo;ed sequence of
<code class="code">gnutls_certificate_status_t</code>  flags.
</p>
<p>When a certificate chain of  <code class="code">cert_list_size</code> with more than one certificates is
provided, the verification status will apply to the first certificate in the chain
that failed verification. The verification process starts from the end of the chain
(from CA to end certificate). The first certificate in the chain must be the end-certificate
while the rest of the members may be sorted or not.
</p>
<p>Additionally a certificate verification profile can be specified
from the ones in <code class="code">gnutls_certificate_verification_profiles_t</code>  by
ORing the result of <code class="code">GNUTLS_PROFILE_TO_VFLAGS()</code>  to the verification
flags.
</p>
<p>Additional verification parameters are possible via the  <code class="code">data</code> types; the
acceptable types are <code class="code">GNUTLS_DT_DNS_HOSTNAME</code> , <code class="code">GNUTLS_DT_IP_ADDRESS</code>  and <code class="code">GNUTLS_DT_KEY_PURPOSE_OID</code> .
The former accepts as data a null-terminated hostname, and the latter a null-terminated
object identifier (e.g., <code class="code">GNUTLS_KP_TLS_WWW_SERVER</code> ).
If a DNS hostname is provided then this function will compare
the hostname in the end certificate against the given. If names do not match the
<code class="code">GNUTLS_CERT_UNEXPECTED_OWNER</code>  status flag will be set. In addition it
will consider certificates provided with <code class="code">gnutls_x509_trust_list_add_named_crt()</code> .
</p>
<p>If a key purpose OID is provided and the end-certificate contains the extended key
usage PKIX extension, it will be required to match the provided OID
or be marked for any purpose, otherwise verification will fail with 
<code class="code">GNUTLS_CERT_PURPOSE_MISMATCH</code>  status.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value. Note that verification failure will not result to an
error code, only  <code class="code">voutput</code> will be updated.
</p>
<p><strong class="strong">Since:</strong> 3.3.8
</p></dd></dl>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005ftrust_005flist_005fverify_005fnamed_005fcrt"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_trust_list_verify_named_crt</strong> <code class="def-code-arguments">(gnutls_x509_trust_list_t <var class="var">list</var>, gnutls_x509_crt_t <var class="var">cert</var>, const void * <var class="var">name</var>, size_t <var class="var">name_size</var>, unsigned int <var class="var">flags</var>, unsigned int * <var class="var">voutput</var>, gnutls_verify_output_function <var class="var">func</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005ftrust_005flist_005fverify_005fnamed_005fcrt"> &para;</a></span></dt>
<dd><p><var class="var">list</var>: The list
</p>
<p><var class="var">cert</var>: is the certificate to be verified
</p>
<p><var class="var">name</var>: is the certificate&rsquo;s name
</p>
<p><var class="var">name_size</var>: is the certificate&rsquo;s name size
</p>
<p><var class="var">flags</var>: Flags that may be used to change the verification algorithm. Use OR of the gnutls_certificate_verify_flags enumerations.
</p>
<p><var class="var">voutput</var>: will hold the certificate verification output.
</p>
<p><var class="var">func</var>: If non-null will be called on each chain element verification with the output.
</p>
<p>This function will try to find a certificate that is associated with the provided
name &ndash;see <code class="code">gnutls_x509_trust_list_add_named_crt()</code> . If a match is found the
certificate is considered valid. In addition to that this function will also 
check CRLs. The  <code class="code">voutput</code> parameter will hold an OR&rsquo;ed sequence of 
<code class="code">gnutls_certificate_status_t</code>  flags.
</p>
<p>Additionally a certificate verification profile can be specified
from the ones in <code class="code">gnutls_certificate_verification_profiles_t</code>  by
ORing the result of <code class="code">GNUTLS_PROFILE_TO_VFLAGS()</code>  to the verification
flags.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.0.0
</p></dd></dl>





<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005ftrust_005flist_005fadd_005ftrust_005ffile"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_trust_list_add_trust_file</strong> <code class="def-code-arguments">(gnutls_x509_trust_list_t <var class="var">list</var>, const char * <var class="var">ca_file</var>, const char * <var class="var">crl_file</var>, gnutls_x509_crt_fmt_t <var class="var">type</var>, unsigned int <var class="var">tl_flags</var>, unsigned int <var class="var">tl_vflags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005ftrust_005flist_005fadd_005ftrust_005ffile"> &para;</a></span></dt>
<dd><p><var class="var">list</var>: The list
</p>
<p><var class="var">ca_file</var>: A file containing a list of CAs (optional)
</p>
<p><var class="var">crl_file</var>: A file containing a list of CRLs (optional)
</p>
<p><var class="var">type</var>: The format of the certificates
</p>
<p><var class="var">tl_flags</var>: flags from <code class="code">gnutls_trust_list_flags_t</code> 
</p>
<p><var class="var">tl_vflags</var>: gnutls_certificate_verify_flags if flags specifies GNUTLS_TL_VERIFY_CRL
</p>
<p>This function will add the given certificate authorities
to the trusted list. PKCS <code class="code">11</code>  URLs are also accepted, instead
of files, by this function. A PKCS <code class="code">11</code>  URL implies a trust
database (a specially marked module in p11-kit); the URL &quot;pkcs11:&quot;
implies all trust databases in the system. Only a single URL specifying
trust databases can be set; they cannot be stacked with multiple calls.
</p>
<p><strong class="strong">Returns:</strong> The number of added elements is returned.
</p>
<p><strong class="strong">Since:</strong> 3.1
</p></dd></dl>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005ftrust_005flist_005fadd_005ftrust_005fmem"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_trust_list_add_trust_mem</strong> <code class="def-code-arguments">(gnutls_x509_trust_list_t <var class="var">list</var>, const gnutls_datum_t * <var class="var">cas</var>, const gnutls_datum_t * <var class="var">crls</var>, gnutls_x509_crt_fmt_t <var class="var">type</var>, unsigned int <var class="var">tl_flags</var>, unsigned int <var class="var">tl_vflags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005ftrust_005flist_005fadd_005ftrust_005fmem"> &para;</a></span></dt>
<dd><p><var class="var">list</var>: The list
</p>
<p><var class="var">cas</var>: A buffer containing a list of CAs (optional)
</p>
<p><var class="var">crls</var>: A buffer containing a list of CRLs (optional)
</p>
<p><var class="var">type</var>: The format of the certificates
</p>
<p><var class="var">tl_flags</var>: flags from <code class="code">gnutls_trust_list_flags_t</code> 
</p>
<p><var class="var">tl_vflags</var>: gnutls_certificate_verify_flags if flags specifies GNUTLS_TL_VERIFY_CRL
</p>
<p>This function will add the given certificate authorities
to the trusted list. 
</p>
<p>If this function is used <code class="code">gnutls_x509_trust_list_deinit()</code>  must be called
with parameter  <code class="code">all</code> being 1.
</p>
<p><strong class="strong">Returns:</strong> The number of added elements is returned.
</p>
<p><strong class="strong">Since:</strong> 3.1
</p></dd></dl>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005ftrust_005flist_005fadd_005fsystem_005ftrust"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_trust_list_add_system_trust</strong> <code class="def-code-arguments">(gnutls_x509_trust_list_t <var class="var">list</var>, unsigned int <var class="var">tl_flags</var>, unsigned int <var class="var">tl_vflags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005ftrust_005flist_005fadd_005fsystem_005ftrust"> &para;</a></span></dt>
<dd><p><var class="var">list</var>: The structure of the list
</p>
<p><var class="var">tl_flags</var>: GNUTLS_TL_*
</p>
<p><var class="var">tl_vflags</var>: gnutls_certificate_verify_flags if flags specifies GNUTLS_TL_VERIFY_CRL
</p>
<p>This function adds the system&rsquo;s default trusted certificate
authorities to the trusted list. Note that on unsupported systems
this function returns <code class="code">GNUTLS_E_UNIMPLEMENTED_FEATURE</code> .
</p>
<p>This function implies the flag <code class="code">GNUTLS_TL_NO_DUPLICATES</code> .
</p>
<p><strong class="strong">Returns:</strong> The number of added elements or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 3.1
</p></dd></dl>

<p>The verification function will verify a given certificate chain against a list of certificate
authorities and certificate revocation lists, and output
a bit-wise OR of elements of the <code class="code">gnutls_certificate_status_t</code> 
enumeration shown in <a class="ref" href="#gnutls_005fcertificate_005fstatus_005ft">Figure 4.2</a>. The <code class="code">GNUTLS_CERT_INVALID</code> flag
is always set on a verification error and more detailed flags will also be set when appropriate.
</p>
<div class="float" id="gnutls_005fcertificate_005fstatus_005ft">


<dl class="table">
<dt><code class="code">GNUTLS_CERT_INVALID</code></dt>
<dd><p>The certificate is not signed by one of the
known authorities or the signature is invalid (deprecated by the flags 
<code class="code">GNUTLS_CERT_SIGNATURE_FAILURE</code>  and <code class="code">GNUTLS_CERT_SIGNER_NOT_FOUND</code> ).
</p></dd>
<dt><code class="code">GNUTLS_CERT_REVOKED</code></dt>
<dd><p>Certificate is revoked by its authority.  In X.509 this will be
set only if CRLs are checked.
</p></dd>
<dt><code class="code">GNUTLS_CERT_SIGNER_NOT_FOUND</code></dt>
<dd><p>The certificate&rsquo;s issuer is not known. 
This is the case if the issuer is not included in the trusted certificate list.
</p></dd>
<dt><code class="code">GNUTLS_CERT_SIGNER_NOT_CA</code></dt>
<dd><p>The certificate&rsquo;s signer was not a CA. This
may happen if this was a version 1 certificate, which is common with
some CAs, or a version 3 certificate without the basic constrains extension.
</p></dd>
<dt><code class="code">GNUTLS_CERT_INSECURE_ALGORITHM</code></dt>
<dd><p>The certificate was signed using an insecure
algorithm such as MD2 or MD5. These algorithms have been broken and
should not be trusted.
</p></dd>
<dt><code class="code">GNUTLS_CERT_NOT_ACTIVATED</code></dt>
<dd><p>The certificate is not yet activated.
</p></dd>
<dt><code class="code">GNUTLS_CERT_EXPIRED</code></dt>
<dd><p>The certificate has expired.
</p></dd>
<dt><code class="code">GNUTLS_CERT_SIGNATURE_FAILURE</code></dt>
<dd><p>The signature verification failed.
</p></dd>
<dt><code class="code">GNUTLS_CERT_REVOCATION_DATA_SUPERSEDED</code></dt>
<dd><p>The revocation data are old and have been superseded.
</p></dd>
<dt><code class="code">GNUTLS_CERT_UNEXPECTED_OWNER</code></dt>
<dd><p>The owner is not the expected one.
</p></dd>
<dt><code class="code">GNUTLS_CERT_REVOCATION_DATA_ISSUED_IN_FUTURE</code></dt>
<dd><p>The revocation data have a future issue date.
</p></dd>
<dt><code class="code">GNUTLS_CERT_SIGNER_CONSTRAINTS_FAILURE</code></dt>
<dd><p>The certificate&rsquo;s signer constraints were
violated.
</p></dd>
<dt><code class="code">GNUTLS_CERT_MISMATCH</code></dt>
<dd><p>The certificate presented isn&rsquo;t the expected one (TOFU)
</p></dd>
<dt><code class="code">GNUTLS_CERT_PURPOSE_MISMATCH</code></dt>
<dd><p>The certificate or an intermediate does not match the intended purpose (extended key usage).
</p></dd>
<dt><code class="code">GNUTLS_CERT_MISSING_OCSP_STATUS</code></dt>
<dd><p>The certificate requires the server to send the certificate status, but no status was received.
</p></dd>
<dt><code class="code">GNUTLS_CERT_INVALID_OCSP_STATUS</code></dt>
<dd><p>The received OCSP status response is invalid.
</p></dd>
<dt><code class="code">GNUTLS_CERT_UNKNOWN_CRIT_EXTENSIONS</code></dt>
<dd><p>The certificate has extensions marked as critical which are not supported.
</p></dd>
</dl>
<div class="caption"><p><strong class="strong">Figure 4.2: </strong>The <code class="code">gnutls_certificate_status_t</code> enumeration.</p></div></div>
<p>An example of certificate verification is shown in <a class="ref" href="#ex_002dverify2">ex-verify2</a>.
It is also possible to have a set of certificates that
are trusted for a particular server but not to authorize other certificates.
This purpose is served by the functions <a class="ref" href="#gnutls_005fx509_005ftrust_005flist_005fadd_005fnamed_005fcrt">gnutls_x509_trust_list_add_named_crt</a> and <a class="ref" href="#gnutls_005fx509_005ftrust_005flist_005fverify_005fnamed_005fcrt">gnutls_x509_trust_list_verify_named_crt</a>.
</p>
<hr>
</div>
<div class="subsubsection-level-extent" id="Verifying-a-certificate-in-the-context-of-TLS-session">
<div class="nav-panel">
<p>
Next: <a href="#Verification-using-PKCS11" accesskey="n" rel="next">Verifying a certificate using PKCS #11</a>, Previous: <a href="#Verifying-X_002e509-certificate-paths" accesskey="p" rel="prev">Verifying <abbr class="acronym">X.509</abbr> certificate paths</a>, Up: <a href="#X_002e509-certificates" accesskey="u" rel="up"><abbr class="acronym">X.509</abbr> certificates</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsubsection" id="Verifying-a-certificate-in-the-context-of-TLS-session-1"><span>4.1.1.8 Verifying a certificate in the context of TLS session<a class="copiable-link" href="#Verifying-a-certificate-in-the-context-of-TLS-session-1"> &para;</a></span></h4>
<a class="index-entry-id" id="index-verifying-certificate-paths-1"></a>
<a class="index-entry-id" id="index-gnutls_005fcertificate_005fverify_005fflags"></a>

<p>When operating in the context of a TLS session, the trusted certificate
authority list may also be set using:
</p><dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fcertificate_005fset_005fx509_005ftrust_005ffile">gnutls_certificate_set_x509_trust_file</a> (gnutls_certificate_credentials_t <var class="var">cred</var>, const char * <var class="var">cafile</var>, gnutls_x509_crt_fmt_t <var class="var">type</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fcertificate_005fset_005fx509_005ftrust_005fdir">gnutls_certificate_set_x509_trust_dir</a> (gnutls_certificate_credentials_t <var class="var">cred</var>, const char * <var class="var">ca_dir</var>, gnutls_x509_crt_fmt_t <var class="var">type</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fcertificate_005fset_005fx509_005fcrl_005ffile">gnutls_certificate_set_x509_crl_file</a> (gnutls_certificate_credentials_t <var class="var">res</var>, const char * <var class="var">crlfile</var>, gnutls_x509_crt_fmt_t <var class="var">type</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fcertificate_005fset_005fx509_005fsystem_005ftrust">gnutls_certificate_set_x509_system_trust</a> (gnutls_certificate_credentials_t <var class="var">cred</var>)</code></dt>
</dl>

<p>These functions allow the specification of the trusted certificate authorities, either
via a file, a directory or use the system-specified certificate authorities. 
Unless the authorities are application specific, it is generally recommended
to use the system trust storage (see <a class="ref" href="#gnutls_005fcertificate_005fset_005fx509_005fsystem_005ftrust">gnutls_certificate_set_x509_system_trust</a>).
</p>
<p>Unlike the previous section it is not required to setup a trusted list, and there
are two approaches to verify the peer&rsquo;s certificate and identity.
The recommended in GnuTLS 3.5.0 and later is via the <a class="ref" href="#gnutls_005fsession_005fset_005fverify_005fcert">gnutls_session_set_verify_cert</a>,
but for older GnuTLS versions you may use an explicit callback set via
<a class="ref" href="#gnutls_005fcertificate_005fset_005fverify_005ffunction">gnutls_certificate_set_verify_function</a> and then utilize
<a class="ref" href="#gnutls_005fcertificate_005fverify_005fpeers3">gnutls_certificate_verify_peers3</a> for verification.
The reported verification status is identical to the verification functions described 
in the previous section.
</p>
<p>Note that in certain cases it is required to check the marked purpose of
the end certificate (e.g. <code class="code">GNUTLS_KP_TLS_WWW_SERVER</code>); in these cases
the more advanced <a class="ref" href="#gnutls_005fsession_005fset_005fverify_005fcert2">gnutls_session_set_verify_cert2</a> and
<a class="ref" href="#gnutls_005fcertificate_005fverify_005fpeers">gnutls_certificate_verify_peers</a> should be used instead.
</p>
<p>There is also the possibility to pass some input to the verification
functions in the form of flags. For <a class="ref" href="#gnutls_005fx509_005ftrust_005flist_005fverify_005fcrt2">gnutls_x509_trust_list_verify_crt2</a> the
flags are passed directly, but for
<a class="ref" href="#gnutls_005fcertificate_005fverify_005fpeers3">gnutls_certificate_verify_peers3</a>, the flags are set using
<a class="ref" href="#gnutls_005fcertificate_005fset_005fverify_005fflags">gnutls_certificate_set_verify_flags</a>.  All the available
flags are part of the enumeration
<code class="code">gnutls_certificate_verify_flags</code> shown in <a class="ref" href="#gnutls_005fcertificate_005fverify_005fflags">Figure 4.3</a>.
</p>
<div class="float" id="gnutls_005fcertificate_005fverify_005fflags">


<dl class="table">
<dt><code class="code">GNUTLS_VERIFY_DISABLE_CA_SIGN</code></dt>
<dd><p>If set a signer does not have to be
a certificate authority. This flag should normally be disabled,
unless you know what this means.
</p></dd>
<dt><code class="code">GNUTLS_VERIFY_DO_NOT_ALLOW_IP_MATCHES</code></dt>
<dd><p>When verifying a hostname
prevent textual IP addresses from matching IP addresses in the
certificate. Treat the input only as a DNS name.
</p></dd>
<dt><code class="code">GNUTLS_VERIFY_DO_NOT_ALLOW_SAME</code></dt>
<dd><p>If a certificate is not signed by
anyone trusted but exists in the trusted CA list do not treat it
as trusted.
</p></dd>
<dt><code class="code">GNUTLS_VERIFY_ALLOW_ANY_X509_V1_CA_CRT</code></dt>
<dd><p>Allow CA certificates that
have version 1 (both root and intermediate). This might be
dangerous since those haven&rsquo;t the basicConstraints
extension. 
</p></dd>
<dt><code class="code">GNUTLS_VERIFY_ALLOW_SIGN_RSA_MD2</code></dt>
<dd><p>Allow certificates to be signed
using the broken MD2 algorithm.
</p></dd>
<dt><code class="code">GNUTLS_VERIFY_ALLOW_SIGN_RSA_MD5</code></dt>
<dd><p>Allow certificates to be signed
using the broken MD5 algorithm.
</p></dd>
<dt><code class="code">GNUTLS_VERIFY_DISABLE_TIME_CHECKS</code></dt>
<dd><p>Disable checking of activation
and expiration validity periods of certificate chains. Don&rsquo;t set
this unless you understand the security implications.
</p></dd>
<dt><code class="code">GNUTLS_VERIFY_DISABLE_TRUSTED_TIME_CHECKS</code></dt>
<dd><p>If set a signer in the trusted
list is never checked for expiration or activation.
</p></dd>
<dt><code class="code">GNUTLS_VERIFY_DO_NOT_ALLOW_X509_V1_CA_CRT</code></dt>
<dd><p>Do not allow trusted CA
certificates that have version 1.  This option is to be used
to deprecate all certificates of version 1.
</p></dd>
<dt><code class="code">GNUTLS_VERIFY_DISABLE_CRL_CHECKS</code></dt>
<dd><p>Disable checking for validity
using certificate revocation lists or the available OCSP data.
</p></dd>
<dt><code class="code">GNUTLS_VERIFY_ALLOW_UNSORTED_CHAIN</code></dt>
<dd><p>A certificate chain is tolerated
if unsorted (the case with many TLS servers out there). This is the
default since GnuTLS 3.1.4.
</p></dd>
<dt><code class="code">GNUTLS_VERIFY_DO_NOT_ALLOW_UNSORTED_CHAIN</code></dt>
<dd><p>Do not tolerate an unsorted
certificate chain.
</p></dd>
<dt><code class="code">GNUTLS_VERIFY_DO_NOT_ALLOW_WILDCARDS</code></dt>
<dd><p>When including a hostname
check in the verification, do not consider any wildcards.
</p></dd>
<dt><code class="code">GNUTLS_VERIFY_USE_TLS1_RSA</code></dt>
<dd><p>This indicates that a (raw) RSA signature is provided
as in the TLS 1.0 protocol. Not all functions accept this flag.
</p></dd>
<dt><code class="code">GNUTLS_VERIFY_IGNORE_UNKNOWN_CRIT_EXTENSIONS</code></dt>
<dd><p>This signals the verification
process, not to fail on unknown critical extensions.
</p></dd>
<dt><code class="code">GNUTLS_VERIFY_ALLOW_SIGN_WITH_SHA1</code></dt>
<dd><p>Allow certificates to be signed
using the broken SHA1 hash algorithm.
</p></dd>
<dt><code class="code">GNUTLS_VERIFY_RSA_PSS_FIXED_SALT_LENGTH</code></dt>
<dd><p>Disallow RSA-PSS signatures made
with mismatching salt length with digest length, as mandated in RFC 8446
4.2.3.
</p></dd>
</dl>
<div class="caption"><p><strong class="strong">Figure 4.3: </strong>The <code class="code">gnutls_certificate_verify_flags</code> enumeration.</p></div></div>
<hr>
</div>
<div class="subsubsection-level-extent" id="Verification-using-PKCS11">
<div class="nav-panel">
<p>
Previous: <a href="#Verifying-a-certificate-in-the-context-of-TLS-session" accesskey="p" rel="prev">Verifying a certificate in the context of TLS session</a>, Up: <a href="#X_002e509-certificates" accesskey="u" rel="up"><abbr class="acronym">X.509</abbr> certificates</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsubsection" id="Verifying-a-certificate-using-PKCS-_002311"><span>4.1.1.9 Verifying a certificate using PKCS #11<a class="copiable-link" href="#Verifying-a-certificate-using-PKCS-_002311"> &para;</a></span></h4>
<a class="index-entry-id" id="index-verifying-certificate-with-pkcs11"></a>

<p>Some systems provide a system wide trusted certificate storage accessible using
the PKCS #11 API. That is, the trusted certificates are queried and accessed using the
PKCS #11 API, and trusted certificate properties, such as purpose, are marked using
attached extensions. One example is the p11-kit trust module<a class="footnote" id="DOCF8" href="#FOOT8"><sup>8</sup></a>.
</p>
<p>These special PKCS #11 modules can be used for GnuTLS certificate verification if marked as trust 
policy modules, i.e., with <code class="code">trust-policy: yes</code> in the p11-kit module file.
The way to use them is by specifying to the file verification function (e.g., <a class="ref" href="#gnutls_005fcertificate_005fset_005fx509_005ftrust_005ffile">gnutls_certificate_set_x509_trust_file</a>),
a pkcs11 URL, or simply <code class="code">pkcs11:</code> to use all the marked with trust policy modules.
</p>
<p>The trust modules of p11-kit assign a purpose to trusted authorities using the extended
key usage object identifiers. The common purposes are shown in <a class="ref" href="#tab_003apurposes">Table 4.4</a>. Note
that typically according to [<a class="ref" href="#RFC5280">RFC5280</a>] the extended key usage object identifiers apply to end certificates. Their
application to CA certificates is an extension used by the trust modules.
</p>
<div class="float" id="tab_003apurposes">
<table class="multitable">
<thead><tr><th width="20%">Purpose</th><th width="20%">OID</th><th width="60%">Description</th></tr></thead>
<tbody><tr><td width="20%">GNUTLS_KP_TLS_WWW_SERVER</td><td width="20%">1.3.6.1.5.5.7.3.1</td><td width="60%">The certificate is to be used for TLS WWW authentication. When in a CA certificate, it
indicates that the CA is allowed to sign certificates for TLS WWW authentication.</td></tr>
<tr><td width="20%">GNUTLS_KP_TLS_WWW_CLIENT</td><td width="20%">1.3.6.1.5.5.7.3.2</td><td width="60%">The certificate is to be used for TLS WWW client authentication. When in a CA certificate, it
indicates that the CA is allowed to sign certificates for TLS WWW client authentication.</td></tr>
<tr><td width="20%">GNUTLS_KP_CODE_SIGNING</td><td width="20%">1.3.6.1.5.5.7.3.3</td><td width="60%">The certificate is to be used for code signing. When in a CA certificate, it
indicates that the CA is allowed to sign certificates for code signing.</td></tr>
<tr><td width="20%">GNUTLS_KP_EMAIL_PROTECTION</td><td width="20%">1.3.6.1.5.5.7.3.4</td><td width="60%">The certificate is to be used for email protection. When in a CA certificate, it
indicates that the CA is allowed to sign certificates for email users.</td></tr>
<tr><td width="20%">GNUTLS_KP_OCSP_SIGNING</td><td width="20%">1.3.6.1.5.5.7.3.9</td><td width="60%">The certificate is to be used for signing OCSP responses. When in a CA certificate, it
indicates that the CA is allowed to sign certificates which sign OCSP responses.</td></tr>
<tr><td width="20%">GNUTLS_KP_ANY</td><td width="20%">2.5.29.37.0</td><td width="60%">The certificate is to be used for any purpose. When in a CA certificate, it
indicates that the CA is allowed to sign any kind of certificates.</td></tr>
</tbody>
</table>
<div class="caption"><p><strong class="strong">Table 4.4: </strong>Key purpose object identifiers.</p></div></div>
<p>With such modules, it is recommended to use the verification functions <a class="ref" href="#gnutls_005fx509_005ftrust_005flist_005fverify_005fcrt2">gnutls_x509_trust_list_verify_crt2</a>,
or <a class="ref" href="#gnutls_005fcertificate_005fverify_005fpeers">gnutls_certificate_verify_peers</a>, which allow to explicitly specify the key purpose. The
other verification functions which do not allow setting a purpose, would operate as if
<code class="code">GNUTLS_KP_TLS_WWW_SERVER</code> was requested from the trusted authorities.
</p>
<hr>
</div>
</div>
<div class="subsection-level-extent" id="OpenPGP-certificates">
<div class="nav-panel">
<p>
Next: <a href="#Raw-public_002dkeys" accesskey="n" rel="next">Raw public-keys</a>, Previous: <a href="#X_002e509-certificates" accesskey="p" rel="prev"><abbr class="acronym">X.509</abbr> certificates</a>, Up: <a href="#Certificate-authentication" accesskey="u" rel="up">Certificate authentication</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="OpenPGP-certificates-1"><span>4.1.2 <abbr class="acronym">OpenPGP</abbr> certificates<a class="copiable-link" href="#OpenPGP-certificates-1"> &para;</a></span></h4>
<a class="index-entry-id" id="index-OpenPGP-certificates"></a>

<p>Previous versions of GnuTLS supported limited <abbr class="acronym">OpenPGP</abbr> key
authentication. That functionality has been deprecated and is no longer
made available. The reason is that, supporting alternative authentication
methods, when X.509 and PKIX were new on the Internet and not well established, seemed like a
good idea, in today&rsquo;s Internet X.509 is unquestionably the main
container for certificates. As such supporting more options with no clear
use-cases, is a distraction that consumes considerable resources for
improving and testing the library. For that we have decided to drop
this functionality completely in 3.6.0.
</p>
<hr>
</div>
<div class="subsection-level-extent" id="Raw-public_002dkeys">
<div class="nav-panel">
<p>
Next: <a href="#Advanced-certificate-verification" accesskey="n" rel="next">Advanced certificate verification</a>, Previous: <a href="#OpenPGP-certificates" accesskey="p" rel="prev"><abbr class="acronym">OpenPGP</abbr> certificates</a>, Up: <a href="#Certificate-authentication" accesskey="u" rel="up">Certificate authentication</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Raw-public_002dkeys-1"><span>4.1.3 Raw public-keys<a class="copiable-link" href="#Raw-public_002dkeys-1"> &para;</a></span></h4>
<a class="index-entry-id" id="index-Raw-public_002dkeys"></a>

<p>There are situations in which a rather large certificate / certificate chain is undesirable or impractical.
An example could be a resource constrained sensor network in which you do want to use authentication of and
encryption between your devices but where your devices lack loads of memory or processing power. Furthermore,
there are situations in which you don&rsquo;t want to or can&rsquo;t rely on a PKIX. TLS is, next to a PKIX environment,
also commonly used with self-signed certificates in smaller deployments where the self-signed certificates
are distributed to all involved protocol endpoints out-of-band. This practice does, however, still require
the overhead of the certificate generation even though none of the information found in the certificate is
actually used.
</p>
<p>With raw public-keys, only a subset of the information found in typical certificates is utilized: namely,
the SubjectPublicKeyInfo structure (in ASN.1 format) of a PKIX certificate that carries the parameters
necessary to describe the public-key. Other parameters found in PKIX certificates are omitted. By omitting
various certificate-related structures, the resulting raw public-key is kept fairly small in comparison to
the original certificate, and the code to process the keys can be simpler.
</p>
<p>It should be noted however, that the authenticity of these raw keys must be verified by an out-of-band mechanism
or something like <abbr class="acronym">TOFU</abbr>.
</p>

<ul class="mini-toc">
<li><a href="#Importing-raw-public_002dkeys" accesskey="1">Importing raw public-keys</a></li>
</ul>
<hr>
<div class="subsubsection-level-extent" id="Importing-raw-public_002dkeys">
<div class="nav-panel">
<p>
Up: <a href="#Raw-public_002dkeys" accesskey="u" rel="up">Raw public-keys</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsubsection" id="Importing-raw-public_002dkeys-1"><span>4.1.3.1 Importing raw public-keys<a class="copiable-link" href="#Importing-raw-public_002dkeys-1"> &para;</a></span></h4>
<p>Raw public-keys and their private counterparts can best be handled by using the abstract types
<code class="code">gnutls_pubkey_t</code> and <code class="code">gnutls_privkey_t</code> respectively. To learn how to use these
see <a class="ref" href="#Abstract-key-types">Abstract key types</a>.
</p>
<hr>
</div>
</div>
<div class="subsection-level-extent" id="Advanced-certificate-verification">
<div class="nav-panel">
<p>
Next: <a href="#Digital-signatures" accesskey="n" rel="next">Digital signatures</a>, Previous: <a href="#Raw-public_002dkeys" accesskey="p" rel="prev">Raw public-keys</a>, Up: <a href="#Certificate-authentication" accesskey="u" rel="up">Certificate authentication</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Advanced-certificate-verification-1"><span>4.1.4 Advanced certificate verification<a class="copiable-link" href="#Advanced-certificate-verification-1"> &para;</a></span></h4>
<a class="index-entry-id" id="index-Certificate-verification"></a>

<p>The verification of X.509 certificates in the HTTPS and other Internet protocols is typically 
done by loading a trusted list of commercial Certificate Authorities
(see <a class="ref" href="#gnutls_005fcertificate_005fset_005fx509_005fsystem_005ftrust">gnutls_certificate_set_x509_system_trust</a>), and using them as trusted anchors.
However, there are several examples (eg. the Diginotar incident) where one of these
authorities was compromised. This risk can be mitigated by using in addition to CA certificate verification,
other verification methods. In this section we list the available in GnuTLS methods.
</p>

<ul class="mini-toc">
<li><a href="#Verifying-a-certificate-using-trust-on-first-use-authentication" accesskey="1">Verifying a certificate using trust on first use authentication</a></li>
<li><a href="#Verifying-a-certificate-using-DANE" accesskey="2">Verifying a certificate using DANE (DNSSEC)</a></li>
</ul>
<hr>
<div class="subsubsection-level-extent" id="Verifying-a-certificate-using-trust-on-first-use-authentication">
<div class="nav-panel">
<p>
Next: <a href="#Verifying-a-certificate-using-DANE" accesskey="n" rel="next">Verifying a certificate using DANE (DNSSEC)</a>, Up: <a href="#Advanced-certificate-verification" accesskey="u" rel="up">Advanced certificate verification</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsubsection" id="Verifying-a-certificate-using-trust-on-first-use-authentication-1"><span>4.1.4.1 Verifying a certificate using trust on first use authentication<a class="copiable-link" href="#Verifying-a-certificate-using-trust-on-first-use-authentication-1"> &para;</a></span></h4>
<a class="index-entry-id" id="index-verifying-certificate-paths-2"></a>
<a class="index-entry-id" id="index-SSH_002dstyle-authentication"></a>
<a class="index-entry-id" id="index-Trust-on-first-use"></a>
<a class="index-entry-id" id="index-Key-pinning"></a>

<p>It is possible to use a trust on first use (TOFU) authentication 
method in GnuTLS. That is the concept used by the SSH programs, where the 
public key of the peer is not verified, or verified in an out-of-bound way,
but subsequent connections to the same peer require the public key to 
remain the same.  Such a system in combination with the typical CA 
verification of a certificate, and OCSP revocation checks,
can help to provide multiple factor verification, where a single point of
failure is not enough to compromise the system. For example a server compromise
may be detected using OCSP, and a CA compromise can be detected using
the trust on first use method.
Such a hybrid system with X.509 and trust on first use authentication is 
shown in <a class="ref" href="#Client-example-with-SSH_002dstyle-certificate-verification">Client example with SSH-style certificate verification</a>.
</p>
<p>See <a class="ref" href="#Certificate-verification">Certificate verification</a> on how to use the available functionality.
</p>
<hr>
</div>
<div class="subsubsection-level-extent" id="Verifying-a-certificate-using-DANE">
<div class="nav-panel">
<p>
Previous: <a href="#Verifying-a-certificate-using-trust-on-first-use-authentication" accesskey="p" rel="prev">Verifying a certificate using trust on first use authentication</a>, Up: <a href="#Advanced-certificate-verification" accesskey="u" rel="up">Advanced certificate verification</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsubsection" id="Verifying-a-certificate-using-DANE-_0028DNSSEC_0029"><span>4.1.4.2 Verifying a certificate using DANE (DNSSEC)<a class="copiable-link" href="#Verifying-a-certificate-using-DANE-_0028DNSSEC_0029"> &para;</a></span></h4>
<a class="index-entry-id" id="index-verifying-certificate-paths-3"></a>
<a class="index-entry-id" id="index-DANE"></a>
<a class="index-entry-id" id="index-DNSSEC"></a>

<p>The DANE protocol is a protocol that can be used to verify TLS certificates
using the DNS (or better DNSSEC) protocols. The DNS security extensions (DNSSEC)
provide an alternative public key infrastructure to the commercial CAs that
are typically used to sign TLS certificates. The DANE protocol takes advantage
of the DNSSEC infrastructure to verify TLS certificates. This can be 
in addition to the verification by CA infrastructure or 
may even replace it where DNSSEC is fully deployed. Note however, that DNSSEC deployment is
fairly new and it would be better to use it as an additional verification
method rather than the only one.
</p>
<p>The DANE functionality is provided by the <code class="code">libgnutls-dane</code> library that is shipped
with GnuTLS and the function prototypes are in <code class="code">gnutls/dane.h</code>. 
See <a class="ref" href="#Certificate-verification">Certificate verification</a> for information on how to use the library.
</p>
<p>Note however, that the DANE RFC mandates the verification methods
one should use in addition to the validation via DNSSEC TLSA entries.
GnuTLS doesn&rsquo;t follow that RFC requirement, and the term DANE verification
in this manual refers to the TLSA entry verification. In GnuTLS any 
other verification methods can be used (e.g., PKIX or TOFU) on top of
DANE.
</p>
<hr>
</div>
</div>
<div class="subsection-level-extent" id="Digital-signatures">
<div class="nav-panel">
<p>
Previous: <a href="#Advanced-certificate-verification" accesskey="p" rel="prev">Advanced certificate verification</a>, Up: <a href="#Certificate-authentication" accesskey="u" rel="up">Certificate authentication</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Digital-signatures-1"><span>4.1.5 Digital signatures<a class="copiable-link" href="#Digital-signatures-1"> &para;</a></span></h4>
<a class="index-entry-id" id="index-digital-signatures"></a>

<p>In this section we will provide some information about digital
signatures, how they work, and give the rationale for disabling some
of the algorithms used.
</p>
<p>Digital signatures work by using somebody&rsquo;s secret key to sign some
arbitrary data.  Then anybody else could use the public key of that
person to verify the signature.  Since the data may be arbitrary it is
not suitable input to a cryptographic digital signature algorithm. For
this reason and also for performance cryptographic hash algorithms are
used to preprocess the input to the signature algorithm. This works as
long as it is difficult enough to generate two different messages with
the same hash algorithm output. In that case the same signature could
be used as a proof for both messages. Nobody wants to sign an innocent
message of donating 1 euro to Greenpeace and find out that they
donated 1.000.000 euros to Bad Inc.
</p>
<p>For a hash algorithm to be called cryptographic the following three
requirements must hold:
</p>
<ol class="enumerate">
<li> Preimage resistance.
That means the algorithm must be one way and given the output of the
hash function <em class="math">H(x)</em>, it is impossible to calculate <em class="math">x</em>.

</li><li> 2nd preimage resistance.
That means that given a pair <em class="math">x,y</em> with <em class="math">y=H(x)</em> it is
impossible to calculate an <em class="math">x'</em> such that <em class="math">y=H(x')</em>.

</li><li> Collision resistance.
That means that it is impossible to calculate random <em class="math">x</em> and
<em class="math">x'</em> such <em class="math">H(x')=H(x)</em>.
</li></ol>

<p>The last two requirements in the list are the most important in
digital signatures. These protect against somebody who would like to
generate two messages with the same hash output. When an algorithm is
considered broken usually it means that the Collision resistance of
the algorithm is less than brute force. Using the birthday paradox the
brute force attack takes
<em class="math">2^{((hash size) / 2)}</em>
operations. Today colliding certificates using the MD5 hash algorithm
have been generated as shown in [<a class="ref" href="#WEGER">WEGER</a>].
</p>
<p>There has been cryptographic results for the SHA-1 hash algorithms as
well, although they are not yet critical.  Before 2004, MD5 had a
presumed collision strength of <em class="math">2^{64}</em>, but it has been showed
to have a collision strength well under <em class="math">2^{50}</em>.  As of November
2005, it is believed that SHA-1&rsquo;s collision strength is around
<em class="math">2^{63}</em>.  We consider this sufficiently hard so that we still
support SHA-1.  We anticipate that SHA-256/386/512 will be used in
publicly-distributed certificates in the future.  When <em class="math">2^{63}</em>
can be considered too weak compared to the computer power available
sometime in the future, SHA-1 will be disabled as well.  The collision
attacks on SHA-1 may also get better, given the new interest in tools
for creating them.
</p>
<ul class="mini-toc">
<li><a href="#Trading-security-for-interoperability" accesskey="1">Trading security for interoperability</a></li>
</ul>
<div class="subsubsection-level-extent" id="Trading-security-for-interoperability">
<h4 class="subsubsection"><span>4.1.5.1 Trading security for interoperability<a class="copiable-link" href="#Trading-security-for-interoperability"> &para;</a></span></h4>

<p>If you connect to a server and use GnuTLS&rsquo; functions to verify the
certificate chain, and get a <code class="code">GNUTLS_CERT_INSECURE_ALGORITHM</code>
validation error (see <a class="ref" href="#Verifying-X_002e509-certificate-paths">Verifying <abbr class="acronym">X.509</abbr> certificate paths</a>), it means
that somewhere in the certificate chain there is a certificate signed
using <code class="code">RSA-MD2</code> or <code class="code">RSA-MD5</code>.  These two digital signature
algorithms are considered broken, so GnuTLS fails verifying
the certificate.  In some situations, it may be useful to be
able to verify the certificate chain anyway, assuming an attacker did
not utilize the fact that these signatures algorithms are broken.
This section will give help on how to achieve that.
</p>
<p>It is important to know that you do not have to enable any of
the flags discussed here to be able to use trusted root CA
certificates self-signed using <code class="code">RSA-MD2</code> or <code class="code">RSA-MD5</code>. The
certificates in the trusted list are considered trusted irrespective
of the signature.
</p>
<p>If you are using <a class="ref" href="#gnutls_005fcertificate_005fverify_005fpeers3">gnutls_certificate_verify_peers3</a> to verify the
certificate chain, you can call
<a class="ref" href="#gnutls_005fcertificate_005fset_005fverify_005fflags">gnutls_certificate_set_verify_flags</a> with the flags:
</p><ul class="itemize mark-bullet">
<li><code class="code">GNUTLS_VERIFY_ALLOW_SIGN_RSA_MD2</code>
</li><li><code class="code">GNUTLS_VERIFY_ALLOW_SIGN_RSA_MD5</code>
</li><li><code class="code">GNUTLS_VERIFY_ALLOW_SIGN_WITH_SHA1</code>
</li><li><code class="code">GNUTLS_VERIFY_ALLOW_BROKEN</code>
</li></ul>
<p>as in the following example:
</p>
<div class="example">
<pre class="example-preformatted">  gnutls_certificate_set_verify_flags (x509cred,
                                       GNUTLS_VERIFY_ALLOW_SIGN_RSA_MD5);
</pre></div>

<p>This will signal the verifier algorithm to enable <code class="code">RSA-MD5</code> when
verifying the certificates.
</p>
<p>If you are using <a class="ref" href="#gnutls_005fx509_005fcrt_005fverify">gnutls_x509_crt_verify</a> or
<a class="ref" href="#gnutls_005fx509_005fcrt_005flist_005fverify">gnutls_x509_crt_list_verify</a>, you can pass the
<code class="code">GNUTLS_VERIFY_ALLOW_SIGN_RSA_MD5</code> parameter directly in the
<code class="code">flags</code> parameter.
</p>
<p>If you are using these flags, it may also be a good idea to warn the
user when verification failure occur for this reason.  The simplest is
to not use the flags by default, and only fall back to using them
after warning the user.  If you wish to inspect the certificate chain
yourself, you can use <a class="ref" href="#gnutls_005fcertificate_005fget_005fpeers">gnutls_certificate_get_peers</a> to extract
the raw server&rsquo;s certificate chain, <a class="ref" href="#gnutls_005fx509_005fcrt_005flist_005fimport">gnutls_x509_crt_list_import</a> to parse each of the certificates, and
then <a class="ref" href="#gnutls_005fx509_005fcrt_005fget_005fsignature_005falgorithm">gnutls_x509_crt_get_signature_algorithm</a> to find out the
signing algorithm used for each certificate.  If any of the
intermediary certificates are using <code class="code">GNUTLS_SIGN_RSA_MD2</code> or
<code class="code">GNUTLS_SIGN_RSA_MD5</code>, you could present a warning.
</p>
<hr>
</div>
</div>
</div>
<div class="section-level-extent" id="More-on-certificate-authentication">
<div class="nav-panel">
<p>
Next: <a href="#Shared_002dkey-and-anonymous-authentication" accesskey="n" rel="next">Shared-key and anonymous authentication</a>, Previous: <a href="#Certificate-authentication" accesskey="p" rel="prev">Certificate authentication</a>, Up: <a href="#Authentication-methods" accesskey="u" rel="up">Authentication methods</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="More-on-certificate-authentication-1"><span>4.2 More on certificate authentication<a class="copiable-link" href="#More-on-certificate-authentication-1"> &para;</a></span></h3>
<a class="index-entry-id" id="index-certificate-authentication-1"></a>

<p>Certificates are not the only structures involved in a public key
infrastructure. Several other structures that are used for certificate
requests, encrypted private keys, revocation lists, GnuTLS abstract key
structures, etc., are discussed in this chapter.
</p>

<ul class="mini-toc">
<li><a href="#PKCS-10-certificate-requests" accesskey="1"><abbr class="acronym">PKCS</abbr> #10 certificate requests</a></li>
<li><a href="#PKIX-certificate-revocation-lists" accesskey="2">PKIX certificate revocation lists</a></li>
<li><a href="#OCSP-certificate-status-checking" accesskey="3"><abbr class="acronym">OCSP</abbr> certificate status checking</a></li>
<li><a href="#OCSP-stapling" accesskey="4">OCSP stapling</a></li>
<li><a href="#Managing-encrypted-keys" accesskey="5">Managing encrypted keys</a></li>
<li><a href="#certtool-Invocation" accesskey="6">Invoking certtool</a></li>
<li><a href="#ocsptool-Invocation" accesskey="7">Invoking ocsptool</a></li>
<li><a href="#danetool-Invocation" accesskey="8">Invoking danetool</a></li>
</ul>
<hr>
<div class="subsection-level-extent" id="PKCS-10-certificate-requests">
<div class="nav-panel">
<p>
Next: <a href="#PKIX-certificate-revocation-lists" accesskey="n" rel="next">PKIX certificate revocation lists</a>, Up: <a href="#More-on-certificate-authentication" accesskey="u" rel="up">More on certificate authentication</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="PKCS-_002310-certificate-requests"><span>4.2.1 <abbr class="acronym">PKCS</abbr> #10 certificate requests<a class="copiable-link" href="#PKCS-_002310-certificate-requests"> &para;</a></span></h4>
<a class="index-entry-id" id="index-certificate-requests"></a>
<a class="index-entry-id" id="index-PKCS-_002310"></a>

<p>A certificate request is a structure, which contain information about
an applicant of a certificate service.  It typically contains a public
key, a distinguished name and secondary data such as a challenge
password. <abbr class="acronym">GnuTLS</abbr> supports the requests defined in
<abbr class="acronym">PKCS</abbr> #10 [<a class="ref" href="#RFC2986">RFC2986</a>]. Other formats of certificate requests
are not currently supported by GnuTLS.
</p>
<p>A certificate request can be generated by
associating it with a private key, setting the
subject&rsquo;s information and finally self signing it.
The last step ensures that the requester is in
possession of the private key.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrq_005fset_005fversion">gnutls_x509_crq_set_version</a> (gnutls_x509_crq_t <var class="var">crq</var>, unsigned int <var class="var">version</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrq_005fset_005fdn">gnutls_x509_crq_set_dn</a> (gnutls_x509_crq_t <var class="var">crq</var>, const char * <var class="var">dn</var>, const char ** <var class="var">err</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrq_005fset_005fdn_005fby_005foid">gnutls_x509_crq_set_dn_by_oid</a> (gnutls_x509_crq_t <var class="var">crq</var>, const char * <var class="var">oid</var>, unsigned int <var class="var">raw_flag</var>, const void * <var class="var">data</var>, unsigned int <var class="var">sizeof_data</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrq_005fset_005fkey_005fusage">gnutls_x509_crq_set_key_usage</a> (gnutls_x509_crq_t <var class="var">crq</var>, unsigned int <var class="var">usage</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrq_005fset_005fkey_005fpurpose_005foid">gnutls_x509_crq_set_key_purpose_oid</a> (gnutls_x509_crq_t <var class="var">crq</var>, const void * <var class="var">oid</var>, unsigned int <var class="var">critical</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrq_005fset_005fbasic_005fconstraints">gnutls_x509_crq_set_basic_constraints</a> (gnutls_x509_crq_t <var class="var">crq</var>, unsigned int <var class="var">ca</var>, int <var class="var">pathLenConstraint</var>)</code></dt>
</dl>

<p>The <a class="ref" href="#gnutls_005fx509_005fcrq_005fset_005fkey">gnutls_x509_crq_set_key</a> and <a class="ref" href="#gnutls_005fx509_005fcrq_005fsign2">gnutls_x509_crq_sign2</a> 
functions associate the request with a private key and sign it. If a 
request is to be signed with a key residing in a PKCS #11 token it is recommended to use
the signing functions shown in <a class="ref" href="#Abstract-key-types">Abstract key types</a>.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fset_005fkey"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_set_key</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, gnutls_x509_privkey_t <var class="var">key</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fset_005fkey"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: should contain a <code class="code">gnutls_x509_crq_t</code>  type
</p>
<p><var class="var">key</var>: holds a private key
</p>
<p>This function will set the public parameters from the given private
key to the request.  
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fsign2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_sign2</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, gnutls_x509_privkey_t <var class="var">key</var>, gnutls_digest_algorithm_t <var class="var">dig</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fsign2"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: should contain a <code class="code">gnutls_x509_crq_t</code>  type
</p>
<p><var class="var">key</var>: holds a private key
</p>
<p><var class="var">dig</var>: The message digest to use, i.e., <code class="code">GNUTLS_DIG_SHA256</code> 
</p>
<p><var class="var">flags</var>: must be 0
</p>
<p>This function will sign the certificate request with a private key.
This must be the same key as the one used in
<code class="code">gnutls_x509_crt_set_key()</code>  since a certificate request is self
signed.
</p>
<p>This must be the last step in a certificate request generation
since all the previously set parameters are now signed.
</p>
<p>A known limitation of this function is, that a newly-signed request will not
be fully functional (e.g., for signature verification), until it
is exported an re-imported.
</p>
<p>After GnuTLS 3.6.1 the value of  <code class="code">dig</code> may be <code class="code">GNUTLS_DIG_UNKNOWN</code> ,
and in that case, a suitable but reasonable for the key algorithm will be selected.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
<code class="code">GNUTLS_E_ASN1_VALUE_NOT_FOUND</code>  is returned if you didn&rsquo;t set all
information in the certificate request (e.g., the version using
<code class="code">gnutls_x509_crq_set_version()</code> ).
</p></dd></dl>

<p>The following example is about generating a certificate request, and a
private key. A certificate request can be later be processed by a CA
which should return a signed certificate.
</p>
<a class="anchor" id="ex_002dcrq"></a><pre class="verbatim">/* This example code is placed in the public domain. */

#ifdef HAVE_CONFIG_H
#include &lt;config.h&gt;
#endif

#include &lt;stdio.h&gt;
#include &lt;stdlib.h&gt;
#include &lt;string.h&gt;
#include &lt;gnutls/gnutls.h&gt;
#include &lt;gnutls/x509.h&gt;
#include &lt;gnutls/abstract.h&gt;
#include &lt;time.h&gt;

/* This example will generate a private key and a certificate
 * request.
 */

int main(void)
{
	gnutls_x509_crq_t crq;
	gnutls_x509_privkey_t key;
	unsigned char buffer[10 * 1024];
	size_t buffer_size = sizeof(buffer);
	unsigned int bits;

	gnutls_global_init();

	/* Initialize an empty certificate request, and
	 * an empty private key.
	 */
	gnutls_x509_crq_init(&amp;crq);

	gnutls_x509_privkey_init(&amp;key);

	/* Generate an RSA key of moderate security.
	 */
	bits = gnutls_sec_param_to_pk_bits(GNUTLS_PK_RSA,
					   GNUTLS_SEC_PARAM_MEDIUM);
	gnutls_x509_privkey_generate(key, GNUTLS_PK_RSA, bits, 0);

	/* Add stuff to the distinguished name
	 */
	gnutls_x509_crq_set_dn_by_oid(crq, GNUTLS_OID_X520_COUNTRY_NAME, 0,
				      &quot;GR&quot;, 2);

	gnutls_x509_crq_set_dn_by_oid(crq, GNUTLS_OID_X520_COMMON_NAME, 0,
				      &quot;Nikos&quot;, strlen(&quot;Nikos&quot;));

	/* Set the request version.
	 */
	gnutls_x509_crq_set_version(crq, 1);

	/* Set a challenge password.
	 */
	gnutls_x509_crq_set_challenge_password(crq,
					       &quot;something to remember here&quot;);

	/* Associate the request with the private key
	 */
	gnutls_x509_crq_set_key(crq, key);

	/* Self sign the certificate request.
	 */
	gnutls_x509_crq_sign2(crq, key, GNUTLS_DIG_SHA1, 0);

	/* Export the PEM encoded certificate request, and
	 * display it.
	 */
	gnutls_x509_crq_export(crq, GNUTLS_X509_FMT_PEM, buffer, &amp;buffer_size);

	printf(&quot;Certificate Request: \n%s&quot;, buffer);

	/* Export the PEM encoded private key, and
	 * display it.
	 */
	buffer_size = sizeof(buffer);
	gnutls_x509_privkey_export(key, GNUTLS_X509_FMT_PEM, buffer,
				   &amp;buffer_size);

	printf(&quot;\n\nPrivate key: \n%s&quot;, buffer);

	gnutls_x509_crq_deinit(crq);
	gnutls_x509_privkey_deinit(key);

	return 0;
}
</pre>
<hr>
</div>
<div class="subsection-level-extent" id="PKIX-certificate-revocation-lists">
<div class="nav-panel">
<p>
Next: <a href="#OCSP-certificate-status-checking" accesskey="n" rel="next"><abbr class="acronym">OCSP</abbr> certificate status checking</a>, Previous: <a href="#PKCS-10-certificate-requests" accesskey="p" rel="prev"><abbr class="acronym">PKCS</abbr> #10 certificate requests</a>, Up: <a href="#More-on-certificate-authentication" accesskey="u" rel="up">More on certificate authentication</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="PKIX-certificate-revocation-lists-1"><span>4.2.2 PKIX certificate revocation lists<a class="copiable-link" href="#PKIX-certificate-revocation-lists-1"> &para;</a></span></h4>
<a class="index-entry-id" id="index-certificate-revocation-lists"></a>
<a class="index-entry-id" id="index-CRL"></a>

<p>A certificate revocation list (CRL) is a structure issued by an authority
periodically containing a list of revoked certificates serial numbers.
The CRL structure is signed with the issuing authorities&rsquo; keys. A typical
CRL contains the fields as shown in <a class="ref" href="#tab_003acrl">Table 4.5</a>.
Certificate revocation lists are used to complement the expiration date of a certificate,
in order to account for other reasons of revocation, such as compromised keys, etc.
</p>
<p>Each CRL is valid for limited amount of
time and is required to provide, except for the current issuing time, also 
the issuing time of the next update.
</p>
<div class="float" id="tab_003acrl">
<table class="multitable">
<thead><tr><th width="20%">Field</th><th width="70%">Description</th></tr></thead>
<tbody><tr><td width="20%">version</td><td width="70%">The field that indicates the version of the CRL structure.</td></tr>
<tr><td width="20%">signature</td><td width="70%">A signature by the issuing authority.</td></tr>
<tr><td width="20%">issuer</td><td width="70%">Holds the issuer&rsquo;s distinguished name.</td></tr>
<tr><td width="20%">thisUpdate</td><td width="70%">The issuing time of the revocation list.</td></tr>
<tr><td width="20%">nextUpdate</td><td width="70%">The issuing time of the revocation list that will update that one.</td></tr>
<tr><td width="20%">revokedCertificates</td><td width="70%">List of revoked certificates serial numbers.</td></tr>
<tr><td width="20%">extensions</td><td width="70%">Optional CRL structure extensions.</td></tr>
</tbody>
</table>
<div class="caption"><p><strong class="strong">Table 4.5: </strong>Certificate revocation list fields.</p></div></div>
<p>The basic CRL structure functions follow.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrl_005finit">gnutls_x509_crl_init</a> (gnutls_x509_crl_t * <var class="var">crl</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrl_005fimport">gnutls_x509_crl_import</a> (gnutls_x509_crl_t <var class="var">crl</var>, const gnutls_datum_t * <var class="var">data</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrl_005fexport">gnutls_x509_crl_export</a> (gnutls_x509_crl_t <var class="var">crl</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, void * <var class="var">output_data</var>, size_t * <var class="var">output_data_size</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrl_005fexport">gnutls_x509_crl_export</a> (gnutls_x509_crl_t <var class="var">crl</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, void * <var class="var">output_data</var>, size_t * <var class="var">output_data_size</var>)</code></dt>
</dl>

<h4 class="subsubheading" id="Reading-a-CRL"><span>Reading a CRL<a class="copiable-link" href="#Reading-a-CRL"> &para;</a></span></h4>

<p>The most important function that extracts the certificate revocation
information from a CRL is <a class="ref" href="#gnutls_005fx509_005fcrl_005fget_005fcrt_005fserial">gnutls_x509_crl_get_crt_serial</a>. Other
functions that return other fields of the CRL structure are also provided.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fget_005fcrt_005fserial"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_get_crt_serial</strong> <code class="def-code-arguments">(gnutls_x509_crl_t <var class="var">crl</var>, unsigned <var class="var">indx</var>, unsigned char * <var class="var">serial</var>, size_t * <var class="var">serial_size</var>, time_t * <var class="var">t</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fget_005fcrt_005fserial"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: should contain a <code class="code">gnutls_x509_crl_t</code>  type
</p>
<p><var class="var">indx</var>: the index of the certificate to extract (starting from 0)
</p>
<p><var class="var">serial</var>: where the serial number will be copied
</p>
<p><var class="var">serial_size</var>: initially holds the size of serial
</p>
<p><var class="var">t</var>: if non null, will hold the time this certificate was revoked
</p>
<p>This function will retrieve the serial number of the specified, by
the index, revoked certificate.
</p>
<p>Note that this function will have performance issues in large sequences
of revoked certificates. In that case use <code class="code">gnutls_x509_crl_iter_crt_serial()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrl_005fget_005fversion">gnutls_x509_crl_get_version</a> (gnutls_x509_crl_t <var class="var">crl</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrl_005fget_005fissuer_005fdn">gnutls_x509_crl_get_issuer_dn</a> (gnutls_x509_crl_t <var class="var">crl</var>, char * <var class="var">buf</var>, size_t * <var class="var">sizeof_buf</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrl_005fget_005fissuer_005fdn2">gnutls_x509_crl_get_issuer_dn2</a> (gnutls_x509_crl_t <var class="var">crl</var>, gnutls_datum_t * <var class="var">dn</var>)</code></dt>
<dt><code class="code"><var class="var">time_t</var> <a class="ref" href="#gnutls_005fx509_005fcrl_005fget_005fthis_005fupdate">gnutls_x509_crl_get_this_update</a> (gnutls_x509_crl_t <var class="var">crl</var>)</code></dt>
<dt><code class="code"><var class="var">time_t</var> <a class="ref" href="#gnutls_005fx509_005fcrl_005fget_005fnext_005fupdate">gnutls_x509_crl_get_next_update</a> (gnutls_x509_crl_t <var class="var">crl</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrl_005fget_005fcrt_005fcount">gnutls_x509_crl_get_crt_count</a> (gnutls_x509_crl_t <var class="var">crl</var>)</code></dt>
</dl>

<h4 class="subsubheading" id="Generation-of-a-CRL"><span>Generation of a CRL<a class="copiable-link" href="#Generation-of-a-CRL"> &para;</a></span></h4>

<p>The following functions can be used to generate a CRL.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrl_005fset_005fversion">gnutls_x509_crl_set_version</a> (gnutls_x509_crl_t <var class="var">crl</var>, unsigned int <var class="var">version</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrl_005fset_005fcrt_005fserial">gnutls_x509_crl_set_crt_serial</a> (gnutls_x509_crl_t <var class="var">crl</var>, const void * <var class="var">serial</var>, size_t <var class="var">serial_size</var>, time_t <var class="var">revocation_time</var>)</code></dt>
</dl>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrl_005fset_005fcrt">gnutls_x509_crl_set_crt</a> (gnutls_x509_crl_t <var class="var">crl</var>, gnutls_x509_crt_t <var class="var">crt</var>, time_t <var class="var">revocation_time</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrl_005fset_005fnext_005fupdate">gnutls_x509_crl_set_next_update</a> (gnutls_x509_crl_t <var class="var">crl</var>, time_t <var class="var">exp_time</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrl_005fset_005fthis_005fupdate">gnutls_x509_crl_set_this_update</a> (gnutls_x509_crl_t <var class="var">crl</var>, time_t <var class="var">act_time</var>)</code></dt>
</dl>

<p>The <a class="ref" href="#gnutls_005fx509_005fcrl_005fsign2">gnutls_x509_crl_sign2</a> and <a class="ref" href="#gnutls_005fx509_005fcrl_005fprivkey_005fsign">gnutls_x509_crl_privkey_sign</a> 
functions sign the revocation list with a private key. The latter function
can be used to sign with a key residing in a PKCS #11 token.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fsign2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_sign2</strong> <code class="def-code-arguments">(gnutls_x509_crl_t <var class="var">crl</var>, gnutls_x509_crt_t <var class="var">issuer</var>, gnutls_x509_privkey_t <var class="var">issuer_key</var>, gnutls_digest_algorithm_t <var class="var">dig</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fsign2"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: should contain a gnutls_x509_crl_t type
</p>
<p><var class="var">issuer</var>: is the certificate of the certificate issuer
</p>
<p><var class="var">issuer_key</var>: holds the issuer&rsquo;s private key
</p>
<p><var class="var">dig</var>: The message digest to use. GNUTLS_DIG_SHA256 is the safe choice unless you know what you&rsquo;re doing.
</p>
<p><var class="var">flags</var>: must be 0
</p>
<p>This function will sign the CRL with the issuer&rsquo;s private key, and
will copy the issuer&rsquo;s information into the CRL.
</p>
<p>This must be the last step in a certificate CRL since all
the previously set parameters are now signed.
</p>
<p>A known limitation of this function is, that a newly-signed CRL will not
be fully functional (e.g., for signature verification), until it
is exported an re-imported.
</p>
<p>After GnuTLS 3.6.1 the value of  <code class="code">dig</code> may be <code class="code">GNUTLS_DIG_UNKNOWN</code> ,
and in that case, a suitable but reasonable for the key algorithm will be selected.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fprivkey_005fsign"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_privkey_sign</strong> <code class="def-code-arguments">(gnutls_x509_crl_t <var class="var">crl</var>, gnutls_x509_crt_t <var class="var">issuer</var>, gnutls_privkey_t <var class="var">issuer_key</var>, gnutls_digest_algorithm_t <var class="var">dig</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fprivkey_005fsign"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: should contain a gnutls_x509_crl_t type
</p>
<p><var class="var">issuer</var>: is the certificate of the certificate issuer
</p>
<p><var class="var">issuer_key</var>: holds the issuer&rsquo;s private key
</p>
<p><var class="var">dig</var>: The message digest to use. GNUTLS_DIG_SHA256 is the safe choice unless you know what you&rsquo;re doing.
</p>
<p><var class="var">flags</var>: must be 0
</p>
<p>This function will sign the CRL with the issuer&rsquo;s private key, and
will copy the issuer&rsquo;s information into the CRL.
</p>
<p>This must be the last step in a certificate CRL since all
the previously set parameters are now signed.
</p>
<p>A known limitation of this function is, that a newly-signed CRL will not
be fully functional (e.g., for signature verification), until it
is exported an re-imported.
</p>
<p>After GnuTLS 3.6.1 the value of  <code class="code">dig</code> may be <code class="code">GNUTLS_DIG_UNKNOWN</code> ,
and in that case, a suitable but reasonable for the key algorithm will be selected.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p>Since 2.12.0
</p></dd></dl>

<p>Few extensions on the CRL structure are supported, including the
CRL number extension and the authority key identifier.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrl_005fset_005fnumber">gnutls_x509_crl_set_number</a> (gnutls_x509_crl_t <var class="var">crl</var>, const void * <var class="var">nr</var>, size_t <var class="var">nr_size</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrl_005fset_005fauthority_005fkey_005fid">gnutls_x509_crl_set_authority_key_id</a> (gnutls_x509_crl_t <var class="var">crl</var>, const void * <var class="var">id</var>, size_t <var class="var">id_size</var>)</code></dt>
</dl>

<hr>
</div>
<div class="subsection-level-extent" id="OCSP-certificate-status-checking">
<div class="nav-panel">
<p>
Next: <a href="#OCSP-stapling" accesskey="n" rel="next">OCSP stapling</a>, Previous: <a href="#PKIX-certificate-revocation-lists" accesskey="p" rel="prev">PKIX certificate revocation lists</a>, Up: <a href="#More-on-certificate-authentication" accesskey="u" rel="up">More on certificate authentication</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="OCSP-certificate-status-checking-1"><span>4.2.3 <abbr class="acronym">OCSP</abbr> certificate status checking<a class="copiable-link" href="#OCSP-certificate-status-checking-1"> &para;</a></span></h4>
<a class="index-entry-id" id="index-certificate-status"></a>
<a class="index-entry-id" id="index-Online-Certificate-Status-Protocol"></a>
<a class="index-entry-id" id="index-OCSP"></a>

<p>Certificates may be revoked before their expiration time has been
reached.  There are several reasons for revoking certificates, but a
typical situation is when the private key associated with a
certificate has been compromised.  Traditionally, Certificate
Revocation Lists (CRLs) have been used by application to implement
revocation checking, however, several problems with CRLs have been
identified [<a class="ref" href="#RIVESTCRL">RIVESTCRL</a>].
</p>
<p>The Online Certificate Status Protocol, or <abbr class="acronym">OCSP</abbr> [<a class="ref" href="#RFC2560">RFC2560</a>], 
is a widely implemented protocol which performs certificate revocation status
checking.  An application that wish to verify the
identity of a peer will verify the certificate against a set of
trusted certificates and then check whether the certificate is listed
in a CRL and/or perform an OCSP check for the certificate.
</p>
<p>Applications are typically expected to contact the OCSP server in order to
request the certificate validity status. The OCSP server replies with an OCSP
response. This section describes this online communication (which can be avoided
when using OCSP stapled responses, for that, see <a class="ref" href="#OCSP-stapling">OCSP stapling</a>).
</p>
<p>Before performing the OCSP query, the application will need to figure
out the address of the OCSP server.  The OCSP server address can be
provided by the local user in manual configuration or may be stored
in the certificate that is being checked.  When stored in a certificate
the OCSP server is in the extension field called the Authority Information 
Access (AIA). The following function
extracts this information from a certificate.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrt_005fget_005fauthority_005finfo_005faccess">gnutls_x509_crt_get_authority_info_access</a> (gnutls_x509_crt_t <var class="var">crt</var>, unsigned int <var class="var">seq</var>, int <var class="var">what</var>, gnutls_datum_t * <var class="var">data</var>, unsigned int * <var class="var">critical</var>)</code></dt>
</dl>

<p>There are several functions in GnuTLS for creating and manipulating
OCSP requests and responses.  The general idea is that a client
application creates an OCSP request object, stores some information
about the certificate to check in the request, and then exports the
request in DER format.  The request will then need to be sent to the
OCSP responder, which needs to be done by the application (GnuTLS does
not send and receive OCSP packets).  Normally an OCSP response is
received that the application will need to import into an OCSP
response object.  The digital signature in the OCSP response needs to
be verified against a set of trust anchors before the information in
the response can be trusted.
</p>
<p>The ASN.1 structure of OCSP requests are briefly as follows.  It is
useful to review the structures to get an understanding of which
fields are modified by GnuTLS functions.
</p>
<div class="example">
<pre class="example-preformatted">OCSPRequest     ::=     SEQUENCE {
    tbsRequest                  TBSRequest,
    optionalSignature   [0]     EXPLICIT Signature OPTIONAL }

TBSRequest      ::=     SEQUENCE {
    version             [0]     EXPLICIT Version DEFAULT v1,
    requestorName       [1]     EXPLICIT GeneralName OPTIONAL,
    requestList                 SEQUENCE OF Request,
    requestExtensions   [2]     EXPLICIT Extensions OPTIONAL }

Request         ::=     SEQUENCE {
    reqCert                     CertID,
    singleRequestExtensions     [0] EXPLICIT Extensions OPTIONAL }

CertID          ::=     SEQUENCE {
    hashAlgorithm       AlgorithmIdentifier,
    issuerNameHash      OCTET STRING, -- Hash of Issuer's DN
    issuerKeyHash       OCTET STRING, -- Hash of Issuers public key
    serialNumber        CertificateSerialNumber }
</pre></div>

<p>The basic functions to initialize, import, export and deallocate OCSP
requests are the following.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005focsp_005freq_005finit">gnutls_ocsp_req_init</a> (gnutls_ocsp_req_t * <var class="var">req</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005focsp_005freq_005fdeinit">gnutls_ocsp_req_deinit</a> (gnutls_ocsp_req_t <var class="var">req</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005focsp_005freq_005fimport">gnutls_ocsp_req_import</a> (gnutls_ocsp_req_t <var class="var">req</var>, const gnutls_datum_t * <var class="var">data</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005focsp_005freq_005fexport">gnutls_ocsp_req_export</a> (gnutls_ocsp_req_const_t <var class="var">req</var>, gnutls_datum_t * <var class="var">data</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005focsp_005freq_005fprint">gnutls_ocsp_req_print</a> (gnutls_ocsp_req_const_t <var class="var">req</var>, gnutls_ocsp_print_formats_t <var class="var">format</var>, gnutls_datum_t * <var class="var">out</var>)</code></dt>
</dl>

<p>To generate an OCSP request the issuer name hash, issuer key hash, and 
the checked certificate&rsquo;s serial number are required. There are two
interfaces available for setting those in an OCSP request.
The is a low-level function when you have the
issuer name hash, issuer key hash, and certificate serial number in
binary form.  The second is more useful if you have the
certificate (and its issuer) in a <code class="code">gnutls_x509_crt_t</code> type.
There is also a function to extract this information from existing an OCSP
request.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005focsp_005freq_005fadd_005fcert_005fid">gnutls_ocsp_req_add_cert_id</a> (gnutls_ocsp_req_t <var class="var">req</var>, gnutls_digest_algorithm_t <var class="var">digest</var>, const gnutls_datum_t * <var class="var">issuer_name_hash</var>, const gnutls_datum_t * <var class="var">issuer_key_hash</var>, const gnutls_datum_t * <var class="var">serial_number</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005focsp_005freq_005fadd_005fcert">gnutls_ocsp_req_add_cert</a> (gnutls_ocsp_req_t <var class="var">req</var>, gnutls_digest_algorithm_t <var class="var">digest</var>, gnutls_x509_crt_t <var class="var">issuer</var>, gnutls_x509_crt_t <var class="var">cert</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005focsp_005freq_005fget_005fcert_005fid">gnutls_ocsp_req_get_cert_id</a> (gnutls_ocsp_req_const_t <var class="var">req</var>, unsigned <var class="var">indx</var>, gnutls_digest_algorithm_t * <var class="var">digest</var>, gnutls_datum_t * <var class="var">issuer_name_hash</var>, gnutls_datum_t * <var class="var">issuer_key_hash</var>, gnutls_datum_t * <var class="var">serial_number</var>)</code></dt>
</dl>

<p>Each OCSP request may contain a number of extensions.  Extensions are
identified by an Object Identifier (OID) and an opaque data buffer
whose syntax and semantics is implied by the OID. You can extract or
set those extensions using the following functions.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005focsp_005freq_005fget_005fextension">gnutls_ocsp_req_get_extension</a> (gnutls_ocsp_req_const_t <var class="var">req</var>, unsigned <var class="var">indx</var>, gnutls_datum_t * <var class="var">oid</var>, unsigned int * <var class="var">critical</var>, gnutls_datum_t * <var class="var">data</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005focsp_005freq_005fset_005fextension">gnutls_ocsp_req_set_extension</a> (gnutls_ocsp_req_t <var class="var">req</var>, const char * <var class="var">oid</var>, unsigned int <var class="var">critical</var>, const gnutls_datum_t * <var class="var">data</var>)</code></dt>
</dl>

<p>A common OCSP Request extension is the nonce extension (OID
1.3.6.1.5.5.7.48.1.2), which is used to avoid replay attacks of
earlier recorded OCSP responses.  The nonce extension carries a value
that is intended to be sufficiently random and unique so that an
attacker will not be able to give a stale response for the same nonce.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005focsp_005freq_005fget_005fnonce">gnutls_ocsp_req_get_nonce</a> (gnutls_ocsp_req_const_t <var class="var">req</var>, unsigned int * <var class="var">critical</var>, gnutls_datum_t * <var class="var">nonce</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005focsp_005freq_005fset_005fnonce">gnutls_ocsp_req_set_nonce</a> (gnutls_ocsp_req_t <var class="var">req</var>, unsigned int <var class="var">critical</var>, const gnutls_datum_t * <var class="var">nonce</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005focsp_005freq_005frandomize_005fnonce">gnutls_ocsp_req_randomize_nonce</a> (gnutls_ocsp_req_t <var class="var">req</var>)</code></dt>
</dl>

<p>The OCSP response structures is a complex structure. A simplified overview
of it is in <a class="ref" href="#tab_003aocsp_002dresponse">Table 4.6</a>. Note that a response may contain 
information on multiple certificates.
</p>
<div class="float" id="tab_003aocsp_002dresponse">
<table class="multitable">
<thead><tr><th width="20%">Field</th><th width="70%">Description</th></tr></thead>
<tbody><tr><td width="20%">version</td><td width="70%">The OCSP response version number (typically 1).</td></tr>
<tr><td width="20%">responder ID</td><td width="70%">An identifier of the responder (DN name or a hash of its key).</td></tr>
<tr><td width="20%">issue time</td><td width="70%">The time the response was generated.</td></tr>
<tr><td width="20%">thisUpdate</td><td width="70%">The issuing time of the revocation information.</td></tr>
<tr><td width="20%">nextUpdate</td><td width="70%">The issuing time of the revocation information that will update that one.</td></tr>
<tr><td width="20%"></td><td width="70%">Revoked certificates</td></tr>
<tr><td width="20%">certificate status</td><td width="70%">The status of the certificate.</td></tr>
<tr><td width="20%">certificate serial</td><td width="70%">The certificate&rsquo;s serial number.</td></tr>
<tr><td width="20%">revocationTime</td><td width="70%">The time the certificate was revoked.</td></tr>
<tr><td width="20%">revocationReason</td><td width="70%">The reason the certificate was revoked.</td></tr>
</tbody>
</table>
<div class="caption"><p><strong class="strong">Table 4.6: </strong>The most important OCSP response fields.</p></div></div>

<p>We provide basic functions for initialization, importing, exporting
and deallocating OCSP responses.  
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005focsp_005fresp_005finit">gnutls_ocsp_resp_init</a> (gnutls_ocsp_resp_t * <var class="var">resp</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005focsp_005fresp_005fdeinit">gnutls_ocsp_resp_deinit</a> (gnutls_ocsp_resp_t <var class="var">resp</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005focsp_005fresp_005fimport">gnutls_ocsp_resp_import</a> (gnutls_ocsp_resp_t <var class="var">resp</var>, const gnutls_datum_t * <var class="var">data</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005focsp_005fresp_005fexport">gnutls_ocsp_resp_export</a> (gnutls_ocsp_resp_const_t <var class="var">resp</var>, gnutls_datum_t * <var class="var">data</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005focsp_005fresp_005fprint">gnutls_ocsp_resp_print</a> (gnutls_ocsp_resp_const_t <var class="var">resp</var>, gnutls_ocsp_print_formats_t <var class="var">format</var>, gnutls_datum_t * <var class="var">out</var>)</code></dt>
</dl>

<p>The utility function that extracts the revocation as well as other information
from a response is shown below.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005fresp_005fget_005fsingle"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ocsp_resp_get_single</strong> <code class="def-code-arguments">(gnutls_ocsp_resp_const_t <var class="var">resp</var>, unsigned <var class="var">indx</var>, gnutls_digest_algorithm_t * <var class="var">digest</var>, gnutls_datum_t * <var class="var">issuer_name_hash</var>, gnutls_datum_t * <var class="var">issuer_key_hash</var>, gnutls_datum_t * <var class="var">serial_number</var>, unsigned int * <var class="var">cert_status</var>, time_t * <var class="var">this_update</var>, time_t * <var class="var">next_update</var>, time_t * <var class="var">revocation_time</var>, unsigned int * <var class="var">revocation_reason</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005fresp_005fget_005fsingle"> &para;</a></span></dt>
<dd><p><var class="var">resp</var>: should contain a <code class="code">gnutls_ocsp_resp_t</code>  type
</p>
<p><var class="var">indx</var>: Specifies response number to get. Use (0) to get the first one.
</p>
<p><var class="var">digest</var>: output variable with <code class="code">gnutls_digest_algorithm_t</code>  hash algorithm
</p>
<p><var class="var">issuer_name_hash</var>: output buffer with hash of issuer&rsquo;s DN
</p>
<p><var class="var">issuer_key_hash</var>: output buffer with hash of issuer&rsquo;s public key
</p>
<p><var class="var">serial_number</var>: output buffer with serial number of certificate to check
</p>
<p><var class="var">cert_status</var>: a certificate status, a <code class="code">gnutls_ocsp_cert_status_t</code>  enum.
</p>
<p><var class="var">this_update</var>: time at which the status is known to be correct.
</p>
<p><var class="var">next_update</var>: when newer information will be available, or (time_t)-1 if unspecified
</p>
<p><var class="var">revocation_time</var>: when  <code class="code">cert_status</code> is <code class="code">GNUTLS_OCSP_CERT_REVOKED</code> , holds time of revocation.
</p>
<p><var class="var">revocation_reason</var>: revocation reason, a <code class="code">gnutls_x509_crl_reason_t</code>  enum.
</p>
<p>This function will return the certificate information of the
 <code class="code">indx</code> &rsquo;ed response in the Basic OCSP Response  <code class="code">resp</code> .  The
information returned corresponds to the OCSP SingleResponse structure
except the final singleExtensions.
</p>
<p>Each of the pointers to output variables may be NULL to indicate
that the caller is not interested in that value.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error code is returned.  If you have reached the last
CertID available <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  will be
returned.
</p></dd></dl>

<p>The possible revocation reasons available in an OCSP response are shown
below.
</p>
<div class="float" id="gnutls_005fx509_005fcrl_005freason_005ft">


<dl class="table">
<dt><code class="code">GNUTLS_X509_CRLREASON_UNSPECIFIED</code></dt>
<dd><p>Unspecified reason.
</p></dd>
<dt><code class="code">GNUTLS_X509_CRLREASON_KEYCOMPROMISE</code></dt>
<dd><p>Private key compromised.
</p></dd>
<dt><code class="code">GNUTLS_X509_CRLREASON_CACOMPROMISE</code></dt>
<dd><p>CA compromised.
</p></dd>
<dt><code class="code">GNUTLS_X509_CRLREASON_AFFILIATIONCHANGED</code></dt>
<dd><p>Affiliation has changed.
</p></dd>
<dt><code class="code">GNUTLS_X509_CRLREASON_SUPERSEDED</code></dt>
<dd><p>Certificate superseded.
</p></dd>
<dt><code class="code">GNUTLS_X509_CRLREASON_CESSATIONOFOPERATION</code></dt>
<dd><p>Operation has ceased.
</p></dd>
<dt><code class="code">GNUTLS_X509_CRLREASON_CERTIFICATEHOLD</code></dt>
<dd><p>Certificate is on hold.
</p></dd>
<dt><code class="code">GNUTLS_X509_CRLREASON_REMOVEFROMCRL</code></dt>
<dd><p>Will be removed from delta CRL.
</p></dd>
<dt><code class="code">GNUTLS_X509_CRLREASON_PRIVILEGEWITHDRAWN</code></dt>
<dd><p>Privilege withdrawn.
</p></dd>
<dt><code class="code">GNUTLS_X509_CRLREASON_AACOMPROMISE</code></dt>
<dd><p>AA compromised.
</p></dd>
</dl>
<div class="caption"><p><strong class="strong">Figure 4.4: </strong>The revocation reasons</p></div></div>
<p>Note, that the OCSP response needs to be verified against some set of trust
anchors before it can be relied upon. It is also important to check
whether the received OCSP response corresponds to the certificate being checked.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005focsp_005fresp_005fverify">gnutls_ocsp_resp_verify</a> (gnutls_ocsp_resp_const_t <var class="var">resp</var>, gnutls_x509_trust_list_t <var class="var">trustlist</var>, unsigned int * <var class="var">verify</var>, unsigned int <var class="var">flags</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005focsp_005fresp_005fverify_005fdirect">gnutls_ocsp_resp_verify_direct</a> (gnutls_ocsp_resp_const_t <var class="var">resp</var>, gnutls_x509_crt_t <var class="var">issuer</var>, unsigned int * <var class="var">verify</var>, unsigned int <var class="var">flags</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005focsp_005fresp_005fcheck_005fcrt">gnutls_ocsp_resp_check_crt</a> (gnutls_ocsp_resp_const_t <var class="var">resp</var>, unsigned int <var class="var">indx</var>, gnutls_x509_crt_t <var class="var">crt</var>)</code></dt>
</dl>

<hr>
</div>
<div class="subsection-level-extent" id="OCSP-stapling">
<div class="nav-panel">
<p>
Next: <a href="#Managing-encrypted-keys" accesskey="n" rel="next">Managing encrypted keys</a>, Previous: <a href="#OCSP-certificate-status-checking" accesskey="p" rel="prev"><abbr class="acronym">OCSP</abbr> certificate status checking</a>, Up: <a href="#More-on-certificate-authentication" accesskey="u" rel="up">More on certificate authentication</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="OCSP-stapling-1"><span>4.2.4 OCSP stapling<a class="copiable-link" href="#OCSP-stapling-1"> &para;</a></span></h4>
<a class="index-entry-id" id="index-certificate-status-1"></a>
<a class="index-entry-id" id="index-Online-Certificate-Status-Protocol-1"></a>
<a class="index-entry-id" id="index-OCSP-stapling"></a>

<p>To avoid applications contacting the OCSP server directly, TLS servers
can provide a &quot;stapled&quot; OCSP response in the TLS handshake. That way
the client application needs to do nothing more. GnuTLS will automatically
consider the stapled OCSP response during the TLS certificate verification
(see <a class="ref" href="#gnutls_005fcertificate_005fverify_005fpeers2">gnutls_certificate_verify_peers2</a>). To disable the automatic
OCSP verification the flag <code class="code">GNUTLS_VERIFY_DISABLE_CRL_CHECKS</code> should be
specified to <a class="ref" href="#gnutls_005fcertificate_005fset_005fverify_005fflags">gnutls_certificate_set_verify_flags</a>.
</p>
<p>Since GnuTLS 3.5.1 the client certificate verification will consider the [<a class="ref" href="#RFC7633">RFC7633</a>]
OCSP-Must-staple certificate extension, and will consider it while checking for stapled
OCSP responses. If the extension is present and no OCSP staple is found, the certificate
verification will fail and the status code <code class="code">GNUTLS_CERT_MISSING_OCSP_STATUS</code> will
returned from the verification function.
</p>
<p>Under TLS 1.2 only one stapled response can be sent by a server, the OCSP
response associated with the end-certificate. Under TLS 1.3 a server can
send multiple OCSP responses, typically one for each certificate in the
certificate chain. The following functions can be used by a client
application to retrieve the OCSP responses as sent by the server.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005focsp_005fstatus_005frequest_005fget">gnutls_ocsp_status_request_get</a> (gnutls_session_t <var class="var">session</var>, gnutls_datum_t * <var class="var">response</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005focsp_005fstatus_005frequest_005fget2">gnutls_ocsp_status_request_get2</a> (gnutls_session_t <var class="var">session</var>, unsigned <var class="var">idx</var>, gnutls_datum_t * <var class="var">response</var>)</code></dt>
</dl>

<p>GnuTLS servers can provide OCSP responses to their clients using the following functions.
</p>
<dl class="table">
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fcertificate_005fset_005fretrieve_005ffunction3">gnutls_certificate_set_retrieve_function3</a> (gnutls_certificate_credentials_t <var class="var">cred</var>, gnutls_certificate_retrieve_function3 * <var class="var">func</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fcertificate_005fset_005focsp_005fstatus_005frequest_005ffile2">gnutls_certificate_set_ocsp_status_request_file2</a> (gnutls_certificate_credentials_t <var class="var">sc</var>, const char * <var class="var">response_file</var>, unsigned <var class="var">idx</var>, gnutls_x509_crt_fmt_t <var class="var">fmt</var>)</code></dt>
<dt><code class="code"><var class="var">unsigned</var> <a class="ref" href="#gnutls_005focsp_005fstatus_005frequest_005fis_005fchecked">gnutls_ocsp_status_request_is_checked</a> (gnutls_session_t <var class="var">session</var>, unsigned int <var class="var">flags</var>)</code></dt>
</dl>

<p>A server is expected to provide the relevant certificate&rsquo;s OCSP responses using
<a class="ref" href="#gnutls_005fcertificate_005fset_005focsp_005fstatus_005frequest_005ffile2">gnutls_certificate_set_ocsp_status_request_file2</a>, and ensure a
periodic reload/renew of the credentials. An estimation of the OCSP responses
expiration can be obtained using the <a class="ref" href="#gnutls_005fcertificate_005fget_005focsp_005fexpiration">gnutls_certificate_get_ocsp_expiration</a> function.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fget_005focsp_005fexpiration"><span class="category-def">Function: </span><span><code class="def-type">time_t</code> <strong class="def-name">gnutls_certificate_get_ocsp_expiration</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">sc</var>, unsigned <var class="var">idx</var>, int <var class="var">oidx</var>, unsigned <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fget_005focsp_005fexpiration"> &para;</a></span></dt>
<dd><p><var class="var">sc</var>: is a credentials structure.
</p>
<p><var class="var">idx</var>: is a certificate chain index as returned by <code class="code">gnutls_certificate_set_key()</code>  and friends
</p>
<p><var class="var">oidx</var>: is an OCSP response index
</p>
<p><var class="var">flags</var>: should be zero
</p>
<p>This function returns the validity of the loaded OCSP responses,
to provide information on when to reload/refresh them.
</p>
<p>Note that the credentials structure should be read-only when in
use, thus when reloading, either the credentials structure must not
be in use by any sessions, or a new credentials structure should be
allocated for new sessions.
</p>
<p>When  <code class="code">oidx</code> is (-1) then the minimum refresh time for all responses
is returned. Otherwise the index specifies the response corresponding
to the  <code class="code">odix</code> certificate in the certificate chain.
</p>
<p><strong class="strong">Returns:</strong> On success, the expiration time of the OCSP response. Otherwise
(time_t)(-1) on error, or (time_t)-2 on out of bounds.
</p>
<p><strong class="strong">Since:</strong> 3.6.3
</p></dd></dl>

<p>Prior to GnuTLS 3.6.4, the functions
<a class="ref" href="#gnutls_005fcertificate_005fset_005focsp_005fstatus_005frequest_005ffunction2">gnutls_certificate_set_ocsp_status_request_function2</a>
<a class="ref" href="#gnutls_005fcertificate_005fset_005focsp_005fstatus_005frequest_005ffile">gnutls_certificate_set_ocsp_status_request_file</a> were provided
to set OCSP responses. These functions are still functional, but cannot be used
to set multiple OCSP responses as allowed by TLS1.3.
</p>
<p>The responses can be updated periodically using the &rsquo;ocsptool&rsquo; command
(see also <a class="ref" href="#ocsptool-Invocation">Invoking ocsptool</a>).
</p>
<div class="example">
<pre class="example-preformatted">ocsptool --ask --load-cert server_cert.pem --load-issuer the_issuer.pem
         --load-signer the_issuer.pem --outfile ocsp.resp
</pre></div>

<p>In order to allow multiple OCSP responses to be concatenated, GnuTLS
supports PEM-encoded OCSP responses. These can be generated using
&rsquo;ocsptool&rsquo; with the &rsquo;&ndash;no-outder&rsquo; parameter.
</p>

<hr>
</div>
<div class="subsection-level-extent" id="Managing-encrypted-keys">
<div class="nav-panel">
<p>
Next: <a href="#certtool-Invocation" accesskey="n" rel="next">Invoking certtool</a>, Previous: <a href="#OCSP-stapling" accesskey="p" rel="prev">OCSP stapling</a>, Up: <a href="#More-on-certificate-authentication" accesskey="u" rel="up">More on certificate authentication</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Managing-encrypted-keys-1"><span>4.2.5 Managing encrypted keys<a class="copiable-link" href="#Managing-encrypted-keys-1"> &para;</a></span></h4>
<a class="index-entry-id" id="index-Encrypted-keys"></a>

<p>Transferring or storing private keys in plain may not be a
good idea, since any compromise is irreparable.
Storing the keys in hardware security modules (see <a class="ref" href="#Smart-cards-and-HSMs">Smart cards and HSMs</a>)
could solve the storage problem but it is not always practical
or efficient enough. This section describes ways to store and
transfer encrypted private keys.
</p>
<p>There are methods for key encryption, namely the
PKCS #8, PKCS #12 and OpenSSL&rsquo;s custom encrypted private key formats. 
The PKCS #8 and the OpenSSL&rsquo;s method allow encryption of the private key, 
while the PKCS #12 method allows, in addition, the bundling of accompanying 
data into the structure. That is typically the corresponding certificate, as 
well as a trusted CA certificate.
</p>
<h4 class="subsubheading" id="High-level-functionality"><span>High level functionality<a class="copiable-link" href="#High-level-functionality"> &para;</a></span></h4>
<p>Generic and higher level private key import functions are available, that
import plain or encrypted keys and will auto-detect the encrypted key format.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fimport_005fx509_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_import_x509_raw</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">pkey</var>, const gnutls_datum_t * <var class="var">data</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, const char * <var class="var">password</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fimport_005fx509_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">pkey</var>: The private key
</p>
<p><var class="var">data</var>: The private key data to be imported
</p>
<p><var class="var">format</var>: The format of the private key
</p>
<p><var class="var">password</var>: A password (optional)
</p>
<p><var class="var">flags</var>: an ORed sequence of gnutls_pkcs_encrypt_flags_t
</p>
<p>This function will import the given private key to the abstract
<code class="code">gnutls_privkey_t</code>  type. 
</p>
<p>The supported formats are basic unencrypted key, PKCS8, PKCS12, 
TSS2, and the openssl format.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.1.0
</p></dd></dl>





<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fprivkey_005fimport2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_privkey_import2</strong> <code class="def-code-arguments">(gnutls_x509_privkey_t <var class="var">key</var>, const gnutls_datum_t * <var class="var">data</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, const char * <var class="var">password</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fprivkey_005fimport2"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: The data to store the parsed key
</p>
<p><var class="var">data</var>: The DER or PEM encoded key.
</p>
<p><var class="var">format</var>: One of DER or PEM
</p>
<p><var class="var">password</var>: A password (optional)
</p>
<p><var class="var">flags</var>: an ORed sequence of gnutls_pkcs_encrypt_flags_t
</p>
<p>This function will import the given DER or PEM encoded key, to 
the native <code class="code">gnutls_x509_privkey_t</code>  format, irrespective of the
input format. The input format is auto-detected.
</p>
<p>The supported formats are basic unencrypted key, PKCS8, PKCS12,
and the openssl format.
</p>
<p>If the provided key is encrypted but no password was given, then
<code class="code">GNUTLS_E_DECRYPTION_FAILED</code>  is returned. Since GnuTLS 3.4.0 this
function will utilize the PIN callbacks if any.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<p>Any keys imported using those functions can be imported to a certificate
credentials structure using <a class="ref" href="#gnutls_005fcertificate_005fset_005fkey">gnutls_certificate_set_key</a>, or alternatively
they can be directly imported using <a class="ref" href="#gnutls_005fcertificate_005fset_005fx509_005fkey_005ffile2">gnutls_certificate_set_x509_key_file2</a>.
</p>
<h4 class="subsubheading" id="PKCS-_00238-structures"><span><abbr class="acronym">PKCS</abbr> #8 structures<a class="copiable-link" href="#PKCS-_00238-structures"> &para;</a></span></h4>
<a class="index-entry-id" id="index-PKCS-_00238"></a>

<p>PKCS #8 keys can be imported and exported as normal private keys using
the functions below. An addition to the normal import functions, are
a password and a flags argument. The flags can be any element of the <code class="code">gnutls_pkcs_encrypt_flags_t</code>
enumeration. Note however, that GnuTLS only supports the PKCS #5 PBES2
encryption scheme. Keys encrypted with the obsolete PBES1 scheme cannot 
be decrypted.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fprivkey_005fimport_005fpkcs8">gnutls_x509_privkey_import_pkcs8</a> (gnutls_x509_privkey_t <var class="var">key</var>, const gnutls_datum_t * <var class="var">data</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, const char * <var class="var">password</var>, unsigned int <var class="var">flags</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fprivkey_005fexport_005fpkcs8">gnutls_x509_privkey_export_pkcs8</a> (gnutls_x509_privkey_t <var class="var">key</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, const char * <var class="var">password</var>, unsigned int <var class="var">flags</var>, void * <var class="var">output_data</var>, size_t * <var class="var">output_data_size</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fprivkey_005fexport2_005fpkcs8">gnutls_x509_privkey_export2_pkcs8</a> (gnutls_x509_privkey_t <var class="var">key</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, const char * <var class="var">password</var>, unsigned int <var class="var">flags</var>, gnutls_datum_t * <var class="var">out</var>)</code></dt>
</dl>

<div class="float" id="gnutls_005fpkcs_005fencrypt_005fflags_005ft">


<dl class="table">
<dt><code class="code">GNUTLS_PKCS_PLAIN</code></dt>
<dd><p>Unencrypted private key.
</p></dd>
<dt><code class="code">GNUTLS_PKCS_PKCS12_3DES</code></dt>
<dd><p>PKCS-12 3DES.
</p></dd>
<dt><code class="code">GNUTLS_PKCS_PKCS12_ARCFOUR</code></dt>
<dd><p>PKCS-12 ARCFOUR.
</p></dd>
<dt><code class="code">GNUTLS_PKCS_PKCS12_RC2_40</code></dt>
<dd><p>PKCS-12 RC2-40.
</p></dd>
<dt><code class="code">GNUTLS_PKCS_PBES2_3DES</code></dt>
<dd><p>PBES2 3DES.
</p></dd>
<dt><code class="code">GNUTLS_PKCS_PBES2_AES_128</code></dt>
<dd><p>PBES2 AES-128.
</p></dd>
<dt><code class="code">GNUTLS_PKCS_PBES2_AES_192</code></dt>
<dd><p>PBES2 AES-192.
</p></dd>
<dt><code class="code">GNUTLS_PKCS_PBES2_AES_256</code></dt>
<dd><p>PBES2 AES-256.
</p></dd>
<dt><code class="code">GNUTLS_PKCS_NULL_PASSWORD</code></dt>
<dd><p>Some schemas distinguish between an empty and a NULL password.
</p></dd>
<dt><code class="code">GNUTLS_PKCS_PBES2_DES</code></dt>
<dd><p>PBES2 single DES.
</p></dd>
<dt><code class="code">GNUTLS_PKCS_PBES1_DES_MD5</code></dt>
<dd><p>PBES1 with single DES; for compatibility with openssl only.
</p></dd>
<dt><code class="code">GNUTLS_PKCS_PBES2_GOST_TC26Z</code></dt>
<dd><p>PBES2 GOST 28147-89 CFB with TC26-Z S-box.
</p></dd>
<dt><code class="code">GNUTLS_PKCS_PBES2_GOST_CPA</code></dt>
<dd><p>PBES2 GOST 28147-89 CFB with CryptoPro-A S-box.
</p></dd>
<dt><code class="code">GNUTLS_PKCS_PBES2_GOST_CPB</code></dt>
<dd><p>PBES2 GOST 28147-89 CFB with CryptoPro-B S-box.
</p></dd>
<dt><code class="code">GNUTLS_PKCS_PBES2_GOST_CPC</code></dt>
<dd><p>PBES2 GOST 28147-89 CFB with CryptoPro-C S-box.
</p></dd>
<dt><code class="code">GNUTLS_PKCS_PBES2_GOST_CPD</code></dt>
<dd><p>PBES2 GOST 28147-89 CFB with CryptoPro-D S-box.
</p></dd>
<dt><code class="code">GNUTLS_PKCS_PBES1_DES_SHA1</code></dt>
<dd><p>PBES1 with single DES; for compatibility purposes only.
</p></dd>
<dt><code class="code">GNUTLS_PKCS_MLDSA_SEED</code></dt>
<dd><p>Emit seed as an ML-DSA private key.
</p></dd>
<dt><code class="code">GNUTLS_PKCS_MLDSA_EXPANDED</code></dt>
<dd><p>Emit an expanded ML-DSA private key.
</p></dd>
</dl>
<div class="caption"><p><strong class="strong">Figure 4.5: </strong>Encryption flags</p></div></div>
<h4 class="subsubheading" id="PKCS-_002312-structures"><span><abbr class="acronym">PKCS</abbr> #12 structures<a class="copiable-link" href="#PKCS-_002312-structures"> &para;</a></span></h4>
<a class="index-entry-id" id="index-PKCS-_002312"></a>

<p>A <abbr class="acronym">PKCS</abbr> #12 structure [<a class="ref" href="#PKCS12">PKCS12</a>] usually contains a user&rsquo;s
private keys and certificates. It is commonly used in browsers to
export and import the user&rsquo;s identities. A file containing such a key can 
be directly imported to a certificate credentials structure by using 
<a class="ref" href="#gnutls_005fcertificate_005fset_005fx509_005fsimple_005fpkcs12_005ffile">gnutls_certificate_set_x509_simple_pkcs12_file</a>.
</p>
<p>In <abbr class="acronym">GnuTLS</abbr> the <abbr class="acronym">PKCS</abbr> #12 structures are handled
using the <code class="code">gnutls_pkcs12_t</code> type. This is an abstract type that
may hold several <code class="code">gnutls_pkcs12_bag_t</code> types.  The bag types are
the holders of the actual data, which may be certificates, private
keys or encrypted data.  A bag of type encrypted should be decrypted
in order for its data to be accessed.
</p>
<p>To reduce the complexity in parsing the structures the simple 
helper function <a class="ref" href="#gnutls_005fpkcs12_005fsimple_005fparse">gnutls_pkcs12_simple_parse</a> is provided. For more
advanced uses, manual parsing of the structure is required using the
functions below.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpkcs12_005fget_005fbag">gnutls_pkcs12_get_bag</a> (gnutls_pkcs12_t <var class="var">pkcs12</var>, int <var class="var">indx</var>, gnutls_pkcs12_bag_t <var class="var">bag</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpkcs12_005fverify_005fmac">gnutls_pkcs12_verify_mac</a> (gnutls_pkcs12_t <var class="var">pkcs12</var>, const char * <var class="var">pass</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpkcs12_005fbag_005fdecrypt">gnutls_pkcs12_bag_decrypt</a> (gnutls_pkcs12_bag_t <var class="var">bag</var>, const char * <var class="var">pass</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpkcs12_005fbag_005fget_005fcount">gnutls_pkcs12_bag_get_count</a> (gnutls_pkcs12_bag_t <var class="var">bag</var>)</code></dt>
</dl>





<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs12_005fsimple_005fparse"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs12_simple_parse</strong> <code class="def-code-arguments">(gnutls_pkcs12_t <var class="var">p12</var>, const char * <var class="var">password</var>, gnutls_x509_privkey_t * <var class="var">key</var>, gnutls_x509_crt_t ** <var class="var">chain</var>, unsigned int * <var class="var">chain_len</var>, gnutls_x509_crt_t ** <var class="var">extra_certs</var>, unsigned int * <var class="var">extra_certs_len</var>, gnutls_x509_crl_t * <var class="var">crl</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs12_005fsimple_005fparse"> &para;</a></span></dt>
<dd><p><var class="var">p12</var>: A pkcs12 type
</p>
<p><var class="var">password</var>: optional password used to decrypt the structure, bags and keys.
</p>
<p><var class="var">key</var>: a structure to store the parsed private key.
</p>
<p><var class="var">chain</var>: the corresponding to key certificate chain (may be <code class="code">NULL</code> )
</p>
<p><var class="var">chain_len</var>: will be updated with the number of additional (may be <code class="code">NULL</code> )
</p>
<p><var class="var">extra_certs</var>: optional pointer to receive an array of additional
certificates found in the PKCS12 structure (may be <code class="code">NULL</code> ).
</p>
<p><var class="var">extra_certs_len</var>: will be updated with the number of additional
certs (may be <code class="code">NULL</code> ).
</p>
<p><var class="var">crl</var>: an optional structure to store the parsed CRL (may be <code class="code">NULL</code> ).
</p>
<p><var class="var">flags</var>: should be zero or one of GNUTLS_PKCS12_SP_*
</p>
<p>This function parses a PKCS12 structure in  <code class="code">pkcs12</code> and extracts the
private key, the corresponding certificate chain, any additional
certificates and a CRL. The structures in  <code class="code">key</code> ,  <code class="code">chain</code>  <code class="code">crl</code> , and  <code class="code">extra_certs</code> must not be initialized.
</p>
<p>The  <code class="code">extra_certs</code> and  <code class="code">extra_certs_len</code> parameters are optional
and both may be set to <code class="code">NULL</code> . If either is non-<code class="code">NULL</code> , then both must
be set. The value for  <code class="code">extra_certs</code> is allocated
using <code class="code">gnutls_malloc()</code> .
</p>
<p>Encrypted PKCS12 bags and PKCS8 private keys are supported, but
only with password based security and the same password for all
operations.
</p>
<p>Note that a PKCS12 structure may contain many keys and/or certificates,
and there is no way to identify which key/certificate pair you want.
For this reason this function is useful for PKCS12 files that contain 
only one key/certificate pair and/or one CRL.
</p>
<p>If the provided structure has encrypted fields but no password
is provided then this function returns <code class="code">GNUTLS_E_DECRYPTION_FAILED</code> .
</p>
<p>Note that normally the chain constructed does not include self signed
certificates, to comply with TLS&rsquo; requirements. If, however, the flag 
<code class="code">GNUTLS_PKCS12_SP_INCLUDE_SELF_SIGNED</code>  is specified then
self signed certificates will be included in the chain.
</p>
<p>Prior to using this function the PKCS <code class="code">12</code>  structure integrity must
be verified using <code class="code">gnutls_pkcs12_verify_mac()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.1.0
</p></dd></dl>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpkcs12_005fbag_005fget_005fdata">gnutls_pkcs12_bag_get_data</a> (gnutls_pkcs12_bag_t <var class="var">bag</var>, unsigned <var class="var">indx</var>, gnutls_datum_t * <var class="var">data</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpkcs12_005fbag_005fget_005fkey_005fid">gnutls_pkcs12_bag_get_key_id</a> (gnutls_pkcs12_bag_t <var class="var">bag</var>, unsigned <var class="var">indx</var>, gnutls_datum_t * <var class="var">id</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpkcs12_005fbag_005fget_005ffriendly_005fname">gnutls_pkcs12_bag_get_friendly_name</a> (gnutls_pkcs12_bag_t <var class="var">bag</var>, unsigned <var class="var">indx</var>, char ** <var class="var">name</var>)</code></dt>
</dl>

<p>The functions below are used to generate a PKCS #12 structure. An example
of their usage is shown at <a class="ref" href="#PKCS12-structure-generation-example">PKCS #12 structure generation example</a>.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpkcs12_005fset_005fbag">gnutls_pkcs12_set_bag</a> (gnutls_pkcs12_t <var class="var">pkcs12</var>, gnutls_pkcs12_bag_t <var class="var">bag</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpkcs12_005fbag_005fencrypt">gnutls_pkcs12_bag_encrypt</a> (gnutls_pkcs12_bag_t <var class="var">bag</var>, const char * <var class="var">pass</var>, unsigned int <var class="var">flags</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpkcs12_005fgenerate_005fmac">gnutls_pkcs12_generate_mac</a> (gnutls_pkcs12_t <var class="var">pkcs12</var>, const char * <var class="var">pass</var>)</code></dt>
</dl>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpkcs12_005fbag_005fset_005fdata">gnutls_pkcs12_bag_set_data</a> (gnutls_pkcs12_bag_t <var class="var">bag</var>, gnutls_pkcs12_bag_type_t <var class="var">type</var>, const gnutls_datum_t * <var class="var">data</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpkcs12_005fbag_005fset_005fcrl">gnutls_pkcs12_bag_set_crl</a> (gnutls_pkcs12_bag_t <var class="var">bag</var>, gnutls_x509_crl_t <var class="var">crl</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpkcs12_005fbag_005fset_005fcrt">gnutls_pkcs12_bag_set_crt</a> (gnutls_pkcs12_bag_t <var class="var">bag</var>, gnutls_x509_crt_t <var class="var">crt</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpkcs12_005fbag_005fset_005fkey_005fid">gnutls_pkcs12_bag_set_key_id</a> (gnutls_pkcs12_bag_t <var class="var">bag</var>, unsigned <var class="var">indx</var>, const gnutls_datum_t * <var class="var">id</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpkcs12_005fbag_005fset_005ffriendly_005fname">gnutls_pkcs12_bag_set_friendly_name</a> (gnutls_pkcs12_bag_t <var class="var">bag</var>, unsigned <var class="var">indx</var>, const char * <var class="var">name</var>)</code></dt>
</dl>

<h4 class="subsubheading" id="OpenSSL-encrypted-keys"><span>OpenSSL encrypted keys<a class="copiable-link" href="#OpenSSL-encrypted-keys"> &para;</a></span></h4>
<a class="index-entry-id" id="index-OpenSSL-encrypted-keys"></a>
<p>Unfortunately the structures discussed in the previous sections are
not the only structures that may hold an encrypted private key. For example
the OpenSSL library offers a custom key encryption method. Those structures
are also supported in GnuTLS with <a class="ref" href="#gnutls_005fx509_005fprivkey_005fimport_005fopenssl">gnutls_x509_privkey_import_openssl</a>.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fprivkey_005fimport_005fopenssl"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_privkey_import_openssl</strong> <code class="def-code-arguments">(gnutls_x509_privkey_t <var class="var">key</var>, const gnutls_datum_t * <var class="var">data</var>, const char * <var class="var">password</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fprivkey_005fimport_005fopenssl"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: The data to store the parsed key
</p>
<p><var class="var">data</var>: The DER or PEM encoded key.
</p>
<p><var class="var">password</var>: the password to decrypt the key (if it is encrypted).
</p>
<p>This function will convert the given PEM encrypted to 
the native gnutls_x509_privkey_t format. The
output will be stored in  <code class="code">key</code> .  
</p>
<p>The  <code class="code">password</code> should be in ASCII. If the password is not provided
or wrong then <code class="code">GNUTLS_E_DECRYPTION_FAILED</code>  will be returned.
</p>
<p>If the Certificate is PEM encoded it should have a header of
&quot;PRIVATE KEY&quot; and the &quot;DEK-Info&quot; header. 
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<hr>
</div>
<div class="subsection-level-extent" id="certtool-Invocation">
<div class="nav-panel">
<p>
Next: <a href="#ocsptool-Invocation" accesskey="n" rel="next">Invoking ocsptool</a>, Previous: <a href="#Managing-encrypted-keys" accesskey="p" rel="prev">Managing encrypted keys</a>, Up: <a href="#More-on-certificate-authentication" accesskey="u" rel="up">More on certificate authentication</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Invoking-certtool"><span>4.2.6 Invoking certtool<a class="copiable-link" href="#Invoking-certtool"> &para;</a></span></h4>
<a class="index-entry-id" id="index-certtool"></a>

<p>Tool to parse and generate X.509 certificates, requests and private keys.
It can be used interactively or non interactively by
specifying the template command line option.
</p>
<p>The tool accepts files or supported URIs via the &ndash;infile option. In case PIN
is required for URI access you can provide it using the environment variables GNUTLS_PIN 
and GNUTLS_SO_PIN.
</p>

<a class="anchor" id="certtool-usage"></a><h4 class="subsubheading" id="certtool-help_002fusage-_0028_002d_003f_0029"><span>certtool help/usage (<samp class="option">-?</samp>)<a class="copiable-link" href="#certtool-help_002fusage-_0028_002d_003f_0029"> &para;</a></span></h4>
<a class="index-entry-id" id="index-certtool-help"></a>

<p>The text printed is the same whether selected with the <code class="code">help</code> option
(<samp class="option">--help</samp>) or the <code class="code">more-help</code> option (<samp class="option">--more-help</samp>).  <code class="code">more-help</code> will print
the usage text by passing it through a pager program.
<code class="code">more-help</code> is disabled on platforms without a working
<code class="code">fork(2)</code> function.  The <code class="code">PAGER</code> environment variable is
used to select the program, defaulting to <samp class="file">more</samp>.  Both will exit
with a status code of 0.
</p>
<div class="example">
<pre class="example-preformatted">certtool - GnuTLS certificate tool
Usage:  certtool [ -&lt;flag&gt; [&lt;val&gt;] | --&lt;name&gt;[{=| }&lt;val&gt;] ]... 

None:

   -d, --debug=num            Enable debugging
				- it must be in the range:
				  0 to 9999
   -V, --verbose              More verbose output
       --infile=file          Input file
				- file must pre-exist
       --outfile=str          Output file
       --attime=str           Perform validation at the timestamp instead of the system time

Certificate related options:

   -i, --certificate-info     Print information on the given certificate
       --pubkey-info          Print information on a public key
   -s, --generate-self-signed Generate a self-signed certificate
   -c, --generate-certificate Generate a signed certificate
       --generate-proxy       Generates a proxy certificate
   -u, --update-certificate   Update a signed certificate
       --fingerprint          Print the fingerprint of the given certificate
       --key-id               Print the key ID of the given certificate
       --v1                   Generate an X.509 version 1 certificate (with no extensions)
       --sign-params=str      Sign a certificate with a specific signature algorithm

Certificate request related options:

       --crq-info             Print information on the given certificate request
   -q, --generate-request     Generate a PKCS #10 certificate request
				- prohibits the option 'infile'
       --no-crq-extensions    Do not use extensions in certificate requests

PKCS#12 file related options:

       --p12-info             Print information on a PKCS #12 structure
       --p12-name=str         The PKCS #12 friendly name to use
       --to-p12               Generate a PKCS #12 structure
       --pbmac1               Use PBMAC1 in a PKCS #12 structure

Private key related options:

   -k, --key-info             Print information on a private key
       --p8-info              Print information on a PKCS #8 structure
       --to-rsa               Convert an RSA-PSS key to raw RSA format
   -p, --generate-privkey     Generate a private key
       --key-type=str         Specify the key type to use on key generation
       --key-format=str       Specify the key format to use on key generation
       --bits=num             Specify the number of bits for key generation
       --curve=str            Specify the curve used for EC key generation
       --sec-param=str        Specify the security level [low, legacy, medium, high, ultra]
       --to-p8                Convert a given key to a PKCS #8 structure
   -8, --pkcs8                Use PKCS #8 format for private keys
       --provable             Generate a private key or parameters from a seed using a provable method
       --verify-provable-privkey  Verify a private key generated from a seed using a provable method
       --seed=str             When generating a private key use the given hex-encoded seed

CRL related options:

   -l, --crl-info             Print information on the given CRL structure
       --generate-crl         Generate a CRL
       --verify-crl           Verify a Certificate Revocation List using a trusted list
				- requires the option 'load-ca-certificate'

Certificate verification related options:

   -e, --verify-chain         Verify a PEM encoded certificate chain
       --verify               Verify a PEM encoded certificate (chain) against a trusted set
       --verify-hostname=str  Specify a hostname to be used for certificate chain verification
       --verify-email=str     Specify a email to be used for certificate chain verification
				- prohibits the option 'verify-hostname'
       --verify-purpose=str   Specify a purpose OID to be used for certificate chain verification
       --verify-allow-broken  Allow broken algorithms, such as MD5 for verification
       --verify-profile=str   Specify a security level profile to be used for verification

PKCS#7 structure options:

       --p7-generate          Generate a PKCS #7 structure
       --p7-sign              Signs using a PKCS #7 structure
       --p7-detached-sign     Signs using a detached PKCS #7 structure
       --p7-include-cert      The signer's certificate will be included in the cert list
				- enabled by default
				- disabled as '--no-p7-include-cert'
       --p7-time              Will include a timestamp in the PKCS #7 structure
       --p7-show-data         Will show the embedded data in the PKCS #7 structure
       --p7-info              Print information on a PKCS #7 structure
       --p7-verify            Verify the provided PKCS #7 structure
       --smime-to-p7          Convert S/MIME to PKCS #7 structure

Other options:

       --get-dh-params        List the included PKCS #3 encoded Diffie-Hellman parameters
       --dh-info              Print information PKCS #3 encoded Diffie-Hellman parameters
       --load-privkey=str     Loads a private key file
       --load-pubkey=str      Loads a public key file
       --load-request=str     Loads a certificate request file
       --load-certificate=str Loads a certificate file
       --load-ca-privkey=str  Loads the certificate authority's private key file
       --load-ca-certificate=str Loads the certificate authority's certificate file
       --load-crl=str         Loads the provided CRL
       --load-data=str        Loads auxiliary data
       --password=str         Password to use
       --null-password        Enforce a NULL password
       --empty-password       Enforce an empty password
       --hex-numbers          Print big number in an easier format to parse
       --cprint               In certain operations it prints the information in C-friendly format
       --hash=str             Hash algorithm to use for signing
       --salt-size=num        Specify the RSA-PSS key default salt size
       --label=str            Specify the RSA-OAEP label, encoded in hexadecimal
       --inder                Use DER format for input certificates, private keys, and DH parameters 
       --inraw                an alias for the 'inder' option
       --outder               Use DER format for output certificates, private keys, and DH parameters
       --outraw               an alias for the 'outder' option
       --template=str         Template file to use for non-interactive operation
       --stdout-info          Print information to stdout instead of stderr
       --ask-pass             Enable interaction for entering password when in batch mode
       --pkcs-cipher=str      Cipher to use for PKCS #8 and #12 operations
       --provider=str         Specify the PKCS #11 provider library
       --text                 Output textual information before PEM-encoded certificates, private keys, etc
				- enabled by default
				- disabled as '--no-text'

Version, usage and configuration options:

   -v, --version[=arg]        output version information and exit
   -h, --help                 display extended usage information and exit
   -!, --more-help            extended usage information passed thru pager

Options are specified by doubled hyphens and their name or by a single
hyphen and the flag character.

Tool to parse and generate X.509 certificates, requests and private keys.
It can be used interactively or non interactively by
specifying the template command line option.

The tool accepts files or supported URIs via the --infile option. In case PIN
is required for URI access you can provide it using the environment variables GNUTLS_PIN 
and GNUTLS_SO_PIN.


Please send bug reports to:  &lt;bugs@gnutls.org&gt;

</pre></div>

<h4 class="subsubheading" id="debug-option-_0028_002dd_0029_002e-3"><span>debug option (-d).<a class="copiable-link" href="#debug-option-_0028_002dd_0029_002e-3"> &para;</a></span></h4>
<a class="anchor" id="certtool-debug"></a>
<p>This is the &ldquo;enable debugging&rdquo; option.
This option takes a ArgumentType.NUMBER argument.
Specifies the debug level.
</p><h4 class="subsubheading" id="attime-option_002e-3"><span>attime option.<a class="copiable-link" href="#attime-option_002e-3"> &para;</a></span></h4>
<a class="anchor" id="certtool-attime"></a>
<p>This is the &ldquo;perform validation at the timestamp instead of the system time&rdquo; option.
This option takes a ArgumentType.STRING argument <samp class="file">timestamp</samp>.
timestamp is an instance in time encoded as Unix time or in a human
 readable timestring such as &quot;29 Feb 2004&quot;, &quot;2004-02-29&quot;.
Full documentation available at 
&lt;https://www.gnu.org/software/coreutils/manual/html_node/Date-input-formats.html&gt;
or locally via info &rsquo;(coreutils) date invocation&rsquo;.
<a class="anchor" id="certtool-cert_002doptions"></a></p><h4 class="subsubheading" id="cert_002doptions-options"><span>cert-options options<a class="copiable-link" href="#cert_002doptions-options"> &para;</a></span></h4>
<p>Certificate related options.
</p><h4 class="subsubheading" id="pubkey_002dinfo-option_002e"><span>pubkey-info option.<a class="copiable-link" href="#pubkey_002dinfo-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-pubkey_002dinfo"></a>
<p>This is the &ldquo;print information on a public key&rdquo; option.
The option combined with &ndash;load-request, &ndash;load-pubkey, &ndash;load-privkey and &ndash;load-certificate will extract the public key of the object in question.
</p><h4 class="subsubheading" id="fingerprint-option_002e"><span>fingerprint option.<a class="copiable-link" href="#fingerprint-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-fingerprint"></a>
<p>This is the &ldquo;print the fingerprint of the given certificate&rdquo; option.
This is a simple hash of the DER encoding of the certificate. It can be combined with the &ndash;hash parameter. However, it is recommended for identification to use the key-id which depends only on the certificate&rsquo;s key.
</p><h4 class="subsubheading" id="key_002did-option_002e"><span>key-id option.<a class="copiable-link" href="#key_002did-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-key_002did"></a>
<p>This is the &ldquo;print the key id of the given certificate&rdquo; option.
This is a hash of the public key of the given certificate. It identifies the key uniquely, remains the same on a certificate renewal and depends only on signed fields of the certificate.
</p><h4 class="subsubheading" id="certificate_002dpubkey-option_002e"><span>certificate-pubkey option.<a class="copiable-link" href="#certificate_002dpubkey-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-certificate_002dpubkey"></a>
<p>This is the &ldquo;print certificate&rsquo;s public key&rdquo; option.
This option is deprecated as a duplicate of &ndash;pubkey-info
</p>
<p><strong class="strong">NOTE</strong><strong class="strong">: THIS OPTION IS DEPRECATED</strong>
</p><h4 class="subsubheading" id="sign_002dparams-option_002e"><span>sign-params option.<a class="copiable-link" href="#sign_002dparams-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-sign_002dparams"></a>
<p>This is the &ldquo;sign a certificate with a specific signature algorithm&rdquo; option.
This option takes a ArgumentType.STRING argument.
This option can be combined with &ndash;generate-certificate, to sign the certificate with
a specific signature algorithm variant. The only option supported is &rsquo;RSA-PSS&rsquo;, and should be
specified when the signer does not have a certificate which is marked for RSA-PSS use only.
<a class="anchor" id="certtool-crq_002doptions"></a></p><h4 class="subsubheading" id="crq_002doptions-options"><span>crq-options options<a class="copiable-link" href="#crq_002doptions-options"> &para;</a></span></h4>
<p>Certificate request related options.
</p><h4 class="subsubheading" id="generate_002drequest-option-_0028_002dq_0029_002e"><span>generate-request option (-q).<a class="copiable-link" href="#generate_002drequest-option-_0028_002dq_0029_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-generate_002drequest"></a>
<p>This is the &ldquo;generate a pkcs #10 certificate request&rdquo; option.
</p>
<p>This option has some usage constraints.  It:
</p><ul class="itemize mark-bullet">
<li>must not appear in combination with any of the following options:
infile.
</li></ul>

<p>Will generate a PKCS #10 certificate request. To specify a private key use &ndash;load-privkey.
<a class="anchor" id="certtool-pkcs12_002doptions"></a></p><h4 class="subsubheading" id="pkcs12_002doptions-options"><span>pkcs12-options options<a class="copiable-link" href="#pkcs12_002doptions-options"> &para;</a></span></h4>
<p>PKCS#12 file related options.
</p><h4 class="subsubheading" id="p12_002dinfo-option_002e"><span>p12-info option.<a class="copiable-link" href="#p12_002dinfo-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-p12_002dinfo"></a>
<p>This is the &ldquo;print information on a pkcs #12 structure&rdquo; option.
This option will dump the contents and print the metadata of the provided PKCS #12 structure.
</p><h4 class="subsubheading" id="p12_002dname-option_002e"><span>p12-name option.<a class="copiable-link" href="#p12_002dname-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-p12_002dname"></a>
<p>This is the &ldquo;the pkcs #12 friendly name to use&rdquo; option.
This option takes a ArgumentType.STRING argument.
The name to be used for the primary certificate and private key in a PKCS #12 file.
</p><h4 class="subsubheading" id="to_002dp12-option_002e"><span>to-p12 option.<a class="copiable-link" href="#to_002dp12-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-to_002dp12"></a>
<p>This is the &ldquo;generate a pkcs #12 structure&rdquo; option.
It requires a certificate, a private key and possibly a CA certificate to be specified.
<a class="anchor" id="certtool-key_002doptions"></a></p><h4 class="subsubheading" id="key_002doptions-options"><span>key-options options<a class="copiable-link" href="#key_002doptions-options"> &para;</a></span></h4>
<p>Private key related options.
</p><h4 class="subsubheading" id="p8_002dinfo-option_002e"><span>p8-info option.<a class="copiable-link" href="#p8_002dinfo-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-p8_002dinfo"></a>
<p>This is the &ldquo;print information on a pkcs #8 structure&rdquo; option.
This option will print information about encrypted PKCS #8 structures. That option does not require the decryption of the structure.
</p><h4 class="subsubheading" id="to_002drsa-option_002e"><span>to-rsa option.<a class="copiable-link" href="#to_002drsa-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-to_002drsa"></a>
<p>This is the &ldquo;convert an rsa-pss key to raw rsa format&rdquo; option.
It requires an RSA-PSS key as input and will output a raw RSA
key. This command is necessary for compatibility with applications that
cannot read RSA-PSS keys.
</p><h4 class="subsubheading" id="generate_002dprivkey-option-_0028_002dp_0029_002e"><span>generate-privkey option (-p).<a class="copiable-link" href="#generate_002dprivkey-option-_0028_002dp_0029_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-generate_002dprivkey"></a>
<p>This is the &ldquo;generate a private key&rdquo; option.
When generating RSA-PSS or RSA-OAEP private keys, the &ndash;hash option will
restrict the allowed hash for the key; For RSA-PSS keys the &ndash;salt-size
option is also acceptable.
</p><h4 class="subsubheading" id="key_002dtype-option_002e"><span>key-type option.<a class="copiable-link" href="#key_002dtype-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-key_002dtype"></a>
<p>This is the &ldquo;specify the key type to use on key generation&rdquo; option.
This option takes a ArgumentType.STRING argument.
This option can be combined with &ndash;generate-privkey, to specify
the key type to be generated. Valid options are, &rsquo;rsa&rsquo;, &rsquo;rsa-pss&rsquo;, &rsquo;rsa-oaep&rsquo;, &rsquo;dsa&rsquo;, &rsquo;ecdsa&rsquo;, &rsquo;ed25519, &rsquo;ed448&rsquo;, &rsquo;x25519&rsquo;, and &rsquo;x448&rsquo;.&rsquo;.
When combined with certificate generation it can be used to specify an
RSA-PSS certificate when an RSA key is given.
</p><h4 class="subsubheading" id="key_002dformat-option_002e"><span>key-format option.<a class="copiable-link" href="#key_002dformat-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-key_002dformat"></a>
<p>This is the &ldquo;specify the key format to use on key generation&rdquo; option.
This option takes a ArgumentType.STRING argument.
This option can be combined with &ndash;generate-privkey, to specify
the key format to be generated, when the key type is ML-DSA. Valid options are, &rsquo;seed&rsquo;, &rsquo;expanded&rsquo;, and &rsquo;both&rsquo;.
</p><h4 class="subsubheading" id="curve-option_002e"><span>curve option.<a class="copiable-link" href="#curve-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-curve"></a>
<p>This is the &ldquo;specify the curve used for ec key generation&rdquo; option.
This option takes a ArgumentType.STRING argument.
Supported values are secp192r1, secp224r1, secp256r1, secp384r1 and secp521r1.
</p><h4 class="subsubheading" id="sec_002dparam-option_002e"><span>sec-param option.<a class="copiable-link" href="#sec_002dparam-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-sec_002dparam"></a>
<p>This is the &ldquo;specify the security level [low, legacy, medium, high, ultra]&rdquo; option.
This option takes a ArgumentType.STRING argument <samp class="file">Security parameter</samp>.
This is alternative to the bits option.
</p><h4 class="subsubheading" id="to_002dp8-option_002e"><span>to-p8 option.<a class="copiable-link" href="#to_002dp8-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-to_002dp8"></a>
<p>This is the &ldquo;convert a given key to a pkcs #8 structure&rdquo; option.
This needs to be combined with &ndash;load-privkey.
</p><h4 class="subsubheading" id="provable-option_002e"><span>provable option.<a class="copiable-link" href="#provable-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-provable"></a>
<p>This is the &ldquo;generate a private key or parameters from a seed using a provable method&rdquo; option.
This will use the FIPS PUB186-4 algorithms (i.e., Shawe-Taylor) for provable key generation.
When specified the private keys or parameters will be generated from a seed, and can be
later validated with &ndash;verify-provable-privkey to be correctly generated from the seed. You may
specify &ndash;seed or allow GnuTLS to generate one (recommended). This option can be combined with
&ndash;generate-privkey or &ndash;generate-dh-params.
</p>
<p>That option applies to RSA and DSA keys. On the DSA keys the PQG parameters
are generated using the seed, and on RSA the two primes.
</p><h4 class="subsubheading" id="verify_002dprovable_002dprivkey-option_002e"><span>verify-provable-privkey option.<a class="copiable-link" href="#verify_002dprovable_002dprivkey-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-verify_002dprovable_002dprivkey"></a>
<p>This is the &ldquo;verify a private key generated from a seed using a provable method&rdquo; option.
This will use the FIPS-186-4 algorithms for provable key generation. You may specify &ndash;seed or use the seed stored in the private key structure.
</p><h4 class="subsubheading" id="seed-option_002e"><span>seed option.<a class="copiable-link" href="#seed-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-seed"></a>
<p>This is the &ldquo;when generating a private key use the given hex-encoded seed&rdquo; option.
This option takes a ArgumentType.STRING argument.
The seed acts as a security parameter for the private key, and
thus a seed size which corresponds to the security level of the private key
should be provided (e.g., 256-bits seed).
<a class="anchor" id="certtool-crl_002doptions"></a></p><h4 class="subsubheading" id="crl_002doptions-options"><span>crl-options options<a class="copiable-link" href="#crl_002doptions-options"> &para;</a></span></h4>
<p>CRL related options.
</p><h4 class="subsubheading" id="generate_002dcrl-option_002e"><span>generate-crl option.<a class="copiable-link" href="#generate_002dcrl-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-generate_002dcrl"></a>
<p>This is the &ldquo;generate a crl&rdquo; option.
This option generates a Certificate Revocation List. When combined with &ndash;load-crl it would use the loaded CRL as base for the generated (i.e., all revoked certificates in the base will be copied to the new CRL).
To add new certificates to the CRL use &ndash;load-certificate.
</p><h4 class="subsubheading" id="verify_002dcrl-option_002e"><span>verify-crl option.<a class="copiable-link" href="#verify_002dcrl-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-verify_002dcrl"></a>
<p>This is the &ldquo;verify a certificate revocation list using a trusted list&rdquo; option.
</p>
<p>This option has some usage constraints.  It:
</p><ul class="itemize mark-bullet">
<li>must appear in combination with the following options:
load-ca-certificate.
</li></ul>

<p>The trusted certificate list must be loaded with &ndash;load-ca-certificate.
<a class="anchor" id="certtool-cert_002dverify_002doptions"></a></p><h4 class="subsubheading" id="cert_002dverify_002doptions-options"><span>cert-verify-options options<a class="copiable-link" href="#cert_002dverify_002doptions-options"> &para;</a></span></h4>
<p>Certificate verification related options.
</p><h4 class="subsubheading" id="verify_002dchain-option-_0028_002de_0029_002e"><span>verify-chain option (-e).<a class="copiable-link" href="#verify_002dchain-option-_0028_002de_0029_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-verify_002dchain"></a>
<p>This is the &ldquo;verify a pem encoded certificate chain&rdquo; option.
Verifies the validity of a certificate chain. That is, an ordered set of
certificates where each one is the issuer of the previous, and the first is
the end-certificate to be validated. In a proper chain the last certificate
is a self signed one. It can be combined with &ndash;verify-purpose or &ndash;verify-hostname.
</p><h4 class="subsubheading" id="verify-option_002e"><span>verify option.<a class="copiable-link" href="#verify-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-verify"></a>
<p>This is the &ldquo;verify a pem encoded certificate (chain) against a trusted set&rdquo; option.
The trusted certificate list can be loaded with &ndash;load-ca-certificate. If no
certificate list is provided, then the system&rsquo;s trusted certificate list is used. Note that
during verification multiple paths may be explored. On a successful verification
the successful path will be the last one. It can be combined with &ndash;verify-purpose or &ndash;verify-hostname.
</p><h4 class="subsubheading" id="verify_002dhostname-option_002e-1"><span>verify-hostname option.<a class="copiable-link" href="#verify_002dhostname-option_002e-1"> &para;</a></span></h4>
<a class="anchor" id="certtool-verify_002dhostname"></a>
<p>This is the &ldquo;specify a hostname to be used for certificate chain verification&rdquo; option.
This option takes a ArgumentType.STRING argument.
This is to be combined with one of the verify certificate options.
</p><h4 class="subsubheading" id="verify_002demail-option_002e"><span>verify-email option.<a class="copiable-link" href="#verify_002demail-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-verify_002demail"></a>
<p>This is the &ldquo;specify a email to be used for certificate chain verification&rdquo; option.
This option takes a ArgumentType.STRING argument.
</p>
<p>This option has some usage constraints.  It:
</p><ul class="itemize mark-bullet">
<li>must not appear in combination with any of the following options:
verify-hostname.
</li></ul>

<p>This is to be combined with one of the verify certificate options.
</p><h4 class="subsubheading" id="verify_002dpurpose-option_002e"><span>verify-purpose option.<a class="copiable-link" href="#verify_002dpurpose-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-verify_002dpurpose"></a>
<p>This is the &ldquo;specify a purpose oid to be used for certificate chain verification&rdquo; option.
This option takes a ArgumentType.STRING argument.
This object identifier restricts the purpose of the certificates to be verified. Example purposes are 1.3.6.1.5.5.7.3.1 (TLS WWW), 1.3.6.1.5.5.7.3.4 (EMAIL) etc. Note that a CA certificate without a purpose set (extended key usage) is valid for any purpose.
</p><h4 class="subsubheading" id="verify_002dallow_002dbroken-option_002e"><span>verify-allow-broken option.<a class="copiable-link" href="#verify_002dallow_002dbroken-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-verify_002dallow_002dbroken"></a>
<p>This is the &ldquo;allow broken algorithms, such as md5 for verification&rdquo; option.
This can be combined with &ndash;p7-verify, &ndash;verify or &ndash;verify-chain.
</p><h4 class="subsubheading" id="verify_002dprofile-option_002e"><span>verify-profile option.<a class="copiable-link" href="#verify_002dprofile-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-verify_002dprofile"></a>
<p>This is the &ldquo;specify a security level profile to be used for verification&rdquo; option.
This option takes a ArgumentType.STRING argument.
This option can be used to specify a certificate verification profile. Certificate
    verification profiles correspond to the security level. This should be one of
    &rsquo;none&rsquo;, &rsquo;very weak&rsquo;, &rsquo;low&rsquo;, &rsquo;legacy&rsquo;, &rsquo;medium&rsquo;, &rsquo;high&rsquo;, &rsquo;ultra&rsquo;,
    &rsquo;future&rsquo;. Note that by default no profile is applied, unless one is set
    as minimum in the gnutls configuration file.
<a class="anchor" id="certtool-pkcs7_002doptions"></a></p><h4 class="subsubheading" id="pkcs7_002doptions-options"><span>pkcs7-options options<a class="copiable-link" href="#pkcs7_002doptions-options"> &para;</a></span></h4>
<p>PKCS#7 structure options.
</p><h4 class="subsubheading" id="p7_002dgenerate-option_002e"><span>p7-generate option.<a class="copiable-link" href="#p7_002dgenerate-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-p7_002dgenerate"></a>
<p>This is the &ldquo;generate a pkcs #7 structure&rdquo; option.
This option generates a PKCS #7 certificate container structure. To add certificates in the structure use &ndash;load-certificate and &ndash;load-crl.
</p><h4 class="subsubheading" id="p7_002dsign-option_002e"><span>p7-sign option.<a class="copiable-link" href="#p7_002dsign-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-p7_002dsign"></a>
<p>This is the &ldquo;signs using a pkcs #7 structure&rdquo; option.
This option generates a PKCS #7 structure containing a signature for the provided data from infile. The data are stored within the structure. The signer certificate has to be specified using &ndash;load-certificate and &ndash;load-privkey. The input to &ndash;load-certificate can be a list of certificates. In case of a list, the first certificate is used for signing and the other certificates are included in the structure.
</p><h4 class="subsubheading" id="p7_002ddetached_002dsign-option_002e"><span>p7-detached-sign option.<a class="copiable-link" href="#p7_002ddetached_002dsign-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-p7_002ddetached_002dsign"></a>
<p>This is the &ldquo;signs using a detached pkcs #7 structure&rdquo; option.
This option generates a PKCS #7 structure containing a signature for the provided data from infile. The signer certificate has to be specified using &ndash;load-certificate and &ndash;load-privkey. The input to &ndash;load-certificate can be a list of certificates. In case of a list, the first certificate is used for signing and the other certificates are included in the structure.
</p><h4 class="subsubheading" id="p7_002dinclude_002dcert-option_002e"><span>p7-include-cert option.<a class="copiable-link" href="#p7_002dinclude_002dcert-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-p7_002dinclude_002dcert"></a>
<p>This is the &ldquo;the signer&rsquo;s certificate will be included in the cert list&rdquo; option.
</p>
<p>This option has some usage constraints.  It:
</p><ul class="itemize mark-bullet">
<li>can be disabled with &ndash;no-p7-include-cert.
</li><li>It is enabled by default.
</li></ul>

<p>This options works with &ndash;p7-sign or &ndash;p7-detached-sign and will include or exclude the signer&rsquo;s certificate into the generated signature.
</p><h4 class="subsubheading" id="p7_002dtime-option_002e"><span>p7-time option.<a class="copiable-link" href="#p7_002dtime-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-p7_002dtime"></a>
<p>This is the &ldquo;will include a timestamp in the pkcs #7 structure&rdquo; option.
This option will include a timestamp in the generated signature
</p><h4 class="subsubheading" id="p7_002dshow_002ddata-option_002e"><span>p7-show-data option.<a class="copiable-link" href="#p7_002dshow_002ddata-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-p7_002dshow_002ddata"></a>
<p>This is the &ldquo;will show the embedded data in the pkcs #7 structure&rdquo; option.
This option can be combined with &ndash;p7-verify or &ndash;p7-info and will display the embedded signed data in the PKCS #7 structure.
</p><h4 class="subsubheading" id="p7_002dverify-option_002e"><span>p7-verify option.<a class="copiable-link" href="#p7_002dverify-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-p7_002dverify"></a>
<p>This is the &ldquo;verify the provided pkcs #7 structure&rdquo; option.
This option verifies the signed PKCS #7 structure. The certificate list to use for verification can be specified with &ndash;load-ca-certificate. When no certificate list is provided, then the system&rsquo;s certificate list is used. Alternatively a direct signer can be provided using &ndash;load-certificate. A key purpose can be enforced with the &ndash;verify-purpose option, and the &ndash;load-data option will utilize detached data.
<a class="anchor" id="certtool-other_002doptions"></a></p><h4 class="subsubheading" id="other_002doptions-options"><span>other-options options<a class="copiable-link" href="#other_002doptions-options"> &para;</a></span></h4>
<p>Other options.
</p><h4 class="subsubheading" id="generate_002ddh_002dparams-option_002e"><span>generate-dh-params option.<a class="copiable-link" href="#generate_002ddh_002dparams-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-generate_002ddh_002dparams"></a>
<p>This is the &ldquo;generate pkcs #3 encoded diffie-hellman parameters&rdquo; option.
The will generate random parameters to be used with
Diffie-Hellman key exchange. The output parameters will be in PKCS #3
format. Note that it is recommended to use the &ndash;get-dh-params option
instead.
</p>
<p><strong class="strong">NOTE</strong><strong class="strong">: THIS OPTION IS DEPRECATED</strong>
</p><h4 class="subsubheading" id="get_002ddh_002dparams-option_002e"><span>get-dh-params option.<a class="copiable-link" href="#get_002ddh_002dparams-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-get_002ddh_002dparams"></a>
<p>This is the &ldquo;list the included pkcs #3 encoded diffie-hellman parameters&rdquo; option.
Returns stored DH parameters in GnuTLS. Those parameters returned
are defined in RFC7919, and can be considered standard parameters for a TLS
key exchange. This option is provided for old applications which require
DH parameters to be specified; modern GnuTLS applications should not require
them.
</p><h4 class="subsubheading" id="load_002dprivkey-option_002e"><span>load-privkey option.<a class="copiable-link" href="#load_002dprivkey-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-load_002dprivkey"></a>
<p>This is the &ldquo;loads a private key file&rdquo; option.
This option takes a ArgumentType.STRING argument.
This can be either a file or a PKCS #11 URL
</p><h4 class="subsubheading" id="load_002dpubkey-option_002e"><span>load-pubkey option.<a class="copiable-link" href="#load_002dpubkey-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-load_002dpubkey"></a>
<p>This is the &ldquo;loads a public key file&rdquo; option.
This option takes a ArgumentType.STRING argument.
This can be either a file or a PKCS #11 URL
</p><h4 class="subsubheading" id="load_002drequest-option_002e"><span>load-request option.<a class="copiable-link" href="#load_002drequest-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-load_002drequest"></a>
<p>This is the &ldquo;loads a certificate request file&rdquo; option.
This option takes a ArgumentType.STRING argument.
This option can be used with a file
</p><h4 class="subsubheading" id="load_002dcertificate-option_002e"><span>load-certificate option.<a class="copiable-link" href="#load_002dcertificate-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-load_002dcertificate"></a>
<p>This is the &ldquo;loads a certificate file&rdquo; option.
This option takes a ArgumentType.STRING argument.
This option can be used with a file
</p><h4 class="subsubheading" id="load_002dca_002dprivkey-option_002e"><span>load-ca-privkey option.<a class="copiable-link" href="#load_002dca_002dprivkey-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-load_002dca_002dprivkey"></a>
<p>This is the &ldquo;loads the certificate authority&rsquo;s private key file&rdquo; option.
This option takes a ArgumentType.STRING argument.
This can be either a file or a PKCS #11 URL
</p><h4 class="subsubheading" id="load_002dca_002dcertificate-option_002e"><span>load-ca-certificate option.<a class="copiable-link" href="#load_002dca_002dcertificate-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-load_002dca_002dcertificate"></a>
<p>This is the &ldquo;loads the certificate authority&rsquo;s certificate file&rdquo; option.
This option takes a ArgumentType.STRING argument.
This can be either a file or a PKCS #11 URL
</p><h4 class="subsubheading" id="load_002dcrl-option_002e"><span>load-crl option.<a class="copiable-link" href="#load_002dcrl-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-load_002dcrl"></a>
<p>This is the &ldquo;loads the provided crl&rdquo; option.
This option takes a ArgumentType.STRING argument.
This option can be used with a file
</p><h4 class="subsubheading" id="load_002ddata-option_002e"><span>load-data option.<a class="copiable-link" href="#load_002ddata-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-load_002ddata"></a>
<p>This is the &ldquo;loads auxiliary data&rdquo; option.
This option takes a ArgumentType.STRING argument.
This option can be used with a file
</p><h4 class="subsubheading" id="password-option_002e"><span>password option.<a class="copiable-link" href="#password-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-password"></a>
<p>This is the &ldquo;password to use&rdquo; option.
This option takes a ArgumentType.STRING argument.
You can use this option to specify the password in the command line instead of reading it from the tty. Note, that the command line arguments are available for view in others in the system. Specifying password as &rdquo; is the same as specifying no password.
</p><h4 class="subsubheading" id="null_002dpassword-option_002e"><span>null-password option.<a class="copiable-link" href="#null_002dpassword-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-null_002dpassword"></a>
<p>This is the &ldquo;enforce a null password&rdquo; option.
This option enforces a NULL password. This is different than the empty or no password in schemas like PKCS #8.
</p><h4 class="subsubheading" id="empty_002dpassword-option_002e"><span>empty-password option.<a class="copiable-link" href="#empty_002dpassword-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-empty_002dpassword"></a>
<p>This is the &ldquo;enforce an empty password&rdquo; option.
This option enforces an empty password. This is different than the NULL or no password in schemas like PKCS #8.
</p><h4 class="subsubheading" id="cprint-option_002e"><span>cprint option.<a class="copiable-link" href="#cprint-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-cprint"></a>
<p>This is the &ldquo;in certain operations it prints the information in c-friendly format&rdquo; option.
In certain operations it prints the information in C-friendly format, suitable for including into C programs.
</p><h4 class="subsubheading" id="rsa-option_002e"><span>rsa option.<a class="copiable-link" href="#rsa-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-rsa"></a>
<p>This is the &ldquo;generate rsa key&rdquo; option.
When combined with &ndash;generate-privkey generates an RSA private key.
</p>
<p><strong class="strong">NOTE</strong><strong class="strong">: THIS OPTION IS DEPRECATED</strong>
</p><h4 class="subsubheading" id="dsa-option_002e"><span>dsa option.<a class="copiable-link" href="#dsa-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-dsa"></a>
<p>This is the &ldquo;generate dsa key&rdquo; option.
When combined with &ndash;generate-privkey generates a DSA private key.
</p>
<p><strong class="strong">NOTE</strong><strong class="strong">: THIS OPTION IS DEPRECATED</strong>
</p><h4 class="subsubheading" id="ecc-option_002e"><span>ecc option.<a class="copiable-link" href="#ecc-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-ecc"></a>
<p>This is the &ldquo;generate ecc (ecdsa) key&rdquo; option.
When combined with &ndash;generate-privkey generates an elliptic curve private key to be used with ECDSA.
</p>
<p><strong class="strong">NOTE</strong><strong class="strong">: THIS OPTION IS DEPRECATED</strong>
</p><h4 class="subsubheading" id="ecdsa-option_002e"><span>ecdsa option.<a class="copiable-link" href="#ecdsa-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-ecdsa"></a>
<p>This is an alias for the <code class="code">ecc</code> option,
see <a class="pxref" href="#certtool-ecc">the ecc option documentation</a>.
</p>
<h4 class="subsubheading" id="hash-option_002e"><span>hash option.<a class="copiable-link" href="#hash-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-hash"></a>
<p>This is the &ldquo;hash algorithm to use for signing&rdquo; option.
This option takes a ArgumentType.STRING argument.
Available hash functions are SHA1, RMD160, SHA256, SHA384, SHA512, SHA3-224, SHA3-256, SHA3-384, SHA3-512.
</p><h4 class="subsubheading" id="salt_002dsize-option_002e"><span>salt-size option.<a class="copiable-link" href="#salt_002dsize-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-salt_002dsize"></a>
<p>This is the &ldquo;specify the rsa-pss key default salt size&rdquo; option.
This option takes a ArgumentType.NUMBER argument.
Typical keys shouldn&rsquo;t set or restrict this option.
</p><h4 class="subsubheading" id="label-option_002e"><span>label option.<a class="copiable-link" href="#label-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-label"></a>
<p>This is the &ldquo;specify the rsa-oaep label, encoded in hexadecimal&rdquo; option.
This option takes a ArgumentType.STRING argument.
Typical keys shouldn&rsquo;t set or restrict this option.
</p><h4 class="subsubheading" id="inder-option_002e"><span>inder option.<a class="copiable-link" href="#inder-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-inder"></a>
<p>This is the &ldquo;use der format for input certificates, private keys, and dh parameters &rdquo; option.
The input files will be assumed to be in DER or RAW format. 
Unlike options that in PEM input would allow multiple input data (e.g. multiple 
certificates), when reading in DER format a single data structure is read.
</p><h4 class="subsubheading" id="inraw-option_002e"><span>inraw option.<a class="copiable-link" href="#inraw-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-inraw"></a>
<p>This is an alias for the <code class="code">inder</code> option,
see <a class="pxref" href="#certtool-inder">the inder option documentation</a>.
</p>
<h4 class="subsubheading" id="outder-option_002e"><span>outder option.<a class="copiable-link" href="#outder-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-outder"></a>
<p>This is the &ldquo;use der format for output certificates, private keys, and dh parameters&rdquo; option.
The output will be in DER or RAW format.
</p><h4 class="subsubheading" id="outraw-option_002e"><span>outraw option.<a class="copiable-link" href="#outraw-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-outraw"></a>
<p>This is an alias for the <code class="code">outder</code> option,
see <a class="pxref" href="#certtool-outder">the outder option documentation</a>.
</p>
<h4 class="subsubheading" id="ask_002dpass-option_002e"><span>ask-pass option.<a class="copiable-link" href="#ask_002dpass-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-ask_002dpass"></a>
<p>This is the &ldquo;enable interaction for entering password when in batch mode&rdquo; option.
This option will enable interaction to enter password when in batch mode. That is useful when the template option has been specified.
</p><h4 class="subsubheading" id="pkcs_002dcipher-option_002e"><span>pkcs-cipher option.<a class="copiable-link" href="#pkcs_002dcipher-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-pkcs_002dcipher"></a>
<p>This is the &ldquo;cipher to use for pkcs #8 and #12 operations&rdquo; option.
This option takes a ArgumentType.STRING argument <samp class="file">Cipher</samp>.
Cipher may be one of 3des, 3des-pkcs12, aes-128, aes-192, aes-256, rc2-40, arcfour.
</p><h4 class="subsubheading" id="provider-option_002e-2"><span>provider option.<a class="copiable-link" href="#provider-option_002e-2"> &para;</a></span></h4>
<a class="anchor" id="certtool-provider"></a>
<p>This is the &ldquo;specify the pkcs #11 provider library&rdquo; option.
This option takes a ArgumentType.STRING argument.
This will override the default options in /etc/gnutls/pkcs11.conf
</p><h4 class="subsubheading" id="text-option_002e"><span>text option.<a class="copiable-link" href="#text-option_002e"> &para;</a></span></h4>
<a class="anchor" id="certtool-text"></a>
<p>This is the &ldquo;output textual information before pem-encoded certificates, private keys, etc&rdquo; option.
</p>
<p>This option has some usage constraints.  It:
</p><ul class="itemize mark-bullet">
<li>can be disabled with &ndash;no-text.
</li><li>It is enabled by default.
</li></ul>

<p>Output textual information before PEM-encoded data
</p><h4 class="subsubheading" id="version-option-_0028_002dv_0029_002e-3"><span>version option (-v).<a class="copiable-link" href="#version-option-_0028_002dv_0029_002e-3"> &para;</a></span></h4>
<a class="anchor" id="certtool-version"></a>
<p>This is the &ldquo;output version information and exit&rdquo; option.
This option takes a ArgumentType.KEYWORD argument.
Output version of program and exit.  The default mode is &lsquo;v&rsquo;, a simple
version.  The &lsquo;c&rsquo; mode will print copyright information and &lsquo;n&rsquo; will
print the full copyright notice.
</p><h4 class="subsubheading" id="help-option-_0028_002dh_0029_002e-3"><span>help option (-h).<a class="copiable-link" href="#help-option-_0028_002dh_0029_002e-3"> &para;</a></span></h4>
<a class="anchor" id="certtool-help"></a>
<p>This is the &ldquo;display extended usage information and exit&rdquo; option.
Display usage information and exit.
</p><h4 class="subsubheading" id="more_002dhelp-option-_0028_002d_0021_0029_002e-3"><span>more-help option (-!).<a class="copiable-link" href="#more_002dhelp-option-_0028_002d_0021_0029_002e-3"> &para;</a></span></h4>
<a class="anchor" id="certtool-more_002dhelp"></a>
<p>This is the &ldquo;extended usage information passed thru pager&rdquo; option.
Pass the extended usage information through a pager.
<a class="anchor" id="certtool-exit-status"></a></p><h4 class="subsubheading" id="certtool-exit-status-1"><span>certtool exit status<a class="copiable-link" href="#certtool-exit-status-1"> &para;</a></span></h4>

<p>One of the following exit values will be returned:
</p><dl class="table">
<dt>&lsquo;<samp class="samp">0 (EXIT_SUCCESS)</samp>&rsquo;</dt>
<dd><p>Successful program execution.
</p></dd>
<dt>&lsquo;<samp class="samp">1 (EXIT_FAILURE)</samp>&rsquo;</dt>
<dd><p>The operation failed or the command syntax was not valid.
</p></dd>
</dl>
<a class="anchor" id="certtool-See-Also"></a><h4 class="subsubheading" id="certtool-See-Also-1"><span>certtool See Also<a class="copiable-link" href="#certtool-See-Also-1"> &para;</a></span></h4>
<p>p11tool (1), psktool (1), srptool (1)
<a class="anchor" id="certtool-Examples"></a></p><h4 class="subsubheading" id="certtool-Examples-1"><span>certtool Examples<a class="copiable-link" href="#certtool-Examples-1"> &para;</a></span></h4>
<h4 class="subsubheading" id="Generating-private-keys"><span>Generating private keys<a class="copiable-link" href="#Generating-private-keys"> &para;</a></span></h4>
<p>To create an RSA private key, run:
</p><div class="example">
<pre class="example-preformatted">$ certtool --generate-privkey --outfile key.pem --rsa
</pre></div>

<p>To create a DSA or elliptic curves (ECDSA) private key use the
above command combined with &rsquo;dsa&rsquo; or &rsquo;ecc&rsquo; options.
</p>
<h4 class="subsubheading" id="Generating-certificate-requests"><span>Generating certificate requests<a class="copiable-link" href="#Generating-certificate-requests"> &para;</a></span></h4>
<p>To create a certificate request (needed when the certificate is  issued  by
another party), run:
</p><div class="example">
<pre class="example-preformatted">certtool --generate-request --load-privkey key.pem \
   --outfile request.pem
</pre></div>

<p>If the private key is stored in a smart card you can generate
a request by specifying the private key object URL.
</p><div class="example">
<pre class="example-preformatted">$ ./certtool --generate-request --load-privkey &quot;pkcs11:...&quot; \
  --load-pubkey &quot;pkcs11:...&quot; --outfile request.pem
</pre></div>


<h4 class="subsubheading" id="Generating-a-self_002dsigned-certificate"><span>Generating a self-signed certificate<a class="copiable-link" href="#Generating-a-self_002dsigned-certificate"> &para;</a></span></h4>
<p>To create a self signed certificate, use the command:
</p><div class="example">
<pre class="example-preformatted">$ certtool --generate-privkey --outfile ca-key.pem
$ certtool --generate-self-signed --load-privkey ca-key.pem \
   --outfile ca-cert.pem
</pre></div>

<p>Note that a self-signed certificate usually belongs to a certificate
authority, that signs other certificates.
</p>
<h4 class="subsubheading" id="Generating-a-certificate"><span>Generating a certificate<a class="copiable-link" href="#Generating-a-certificate"> &para;</a></span></h4>
<p>To generate a certificate using the previous request, use the command:
</p><div class="example">
<pre class="example-preformatted">$ certtool --generate-certificate --load-request request.pem \
   --outfile cert.pem --load-ca-certificate ca-cert.pem \
   --load-ca-privkey ca-key.pem
</pre></div>

<p>To generate a certificate using the private key only, use the command:
</p><div class="example">
<pre class="example-preformatted">$ certtool --generate-certificate --load-privkey key.pem \
   --outfile cert.pem --load-ca-certificate ca-cert.pem \
   --load-ca-privkey ca-key.pem
</pre></div>

<h4 class="subsubheading" id="Certificate-information"><span>Certificate information<a class="copiable-link" href="#Certificate-information"> &para;</a></span></h4>
<p>To view the certificate information, use:
</p><div class="example">
<pre class="example-preformatted">$ certtool --certificate-info --infile cert.pem
</pre></div>

<h4 class="subsubheading" id="Changing-the-certificate-format"><span>Changing the certificate format<a class="copiable-link" href="#Changing-the-certificate-format"> &para;</a></span></h4>
<p>To convert the certificate from PEM to DER format, use:
</p><div class="example">
<pre class="example-preformatted">$ certtool --certificate-info --infile cert.pem --outder --outfile cert.der
</pre></div>

<h4 class="subsubheading" id="PKCS-_002312-structure-generation"><span>PKCS #12 structure generation<a class="copiable-link" href="#PKCS-_002312-structure-generation"> &para;</a></span></h4>
<p>To generate a PKCS #12 structure using the previous key and certificate,
use the command:
</p><div class="example">
<pre class="example-preformatted">$ certtool --load-certificate cert.pem --load-privkey key.pem \
   --to-p12 --outder --outfile key.p12
</pre></div>

<p>Some tools (reportedly web browsers) have problems with that file
because it does not contain the CA certificate for the certificate.
To work around that problem in the tool, you can use the
&ndash;load-ca-certificate parameter as follows:
</p>
<div class="example">
<pre class="example-preformatted">$ certtool --load-ca-certificate ca.pem \
  --load-certificate cert.pem --load-privkey key.pem \
  --to-p12 --outder --outfile key.p12
</pre></div>

<h4 class="subsubheading" id="Obtaining-Diffie_002dHellman-parameters"><span>Obtaining Diffie-Hellman parameters<a class="copiable-link" href="#Obtaining-Diffie_002dHellman-parameters"> &para;</a></span></h4>
<p>To obtain the RFC7919 parameters for Diffie-Hellman key exchange, use the command:
</p><div class="example">
<pre class="example-preformatted">$ certtool --get-dh-params --outfile dh.pem --sec-param medium
</pre></div>

<h4 class="subsubheading" id="Verifying-a-certificate"><span>Verifying a certificate<a class="copiable-link" href="#Verifying-a-certificate"> &para;</a></span></h4>
<p>To verify a certificate in a file against the system&rsquo;s CA trust store
use the following command:
</p><div class="example">
<pre class="example-preformatted">$ certtool --verify --infile cert.pem
</pre></div>

<p>It is also possible to simulate hostname verification with the following
options:
</p><div class="example">
<pre class="example-preformatted">$ certtool --verify --verify-hostname www.example.com --infile cert.pem
</pre></div>


<h4 class="subsubheading" id="Proxy-certificate-generation"><span>Proxy certificate generation<a class="copiable-link" href="#Proxy-certificate-generation"> &para;</a></span></h4>
<p>Proxy certificate can be used to delegate your credential to a
temporary, typically short-lived, certificate.  To create one from the
previously created certificate, first create a temporary key and then
generate a proxy certificate for it, using the commands:
</p>
<div class="example">
<pre class="example-preformatted">$ certtool --generate-privkey &gt; proxy-key.pem
$ certtool --generate-proxy --load-ca-privkey key.pem \
  --load-privkey proxy-key.pem --load-certificate cert.pem \
  --outfile proxy-cert.pem
</pre></div>

<h4 class="subsubheading" id="Certificate-revocation-list-generation"><span>Certificate revocation list generation<a class="copiable-link" href="#Certificate-revocation-list-generation"> &para;</a></span></h4>
<p>To create an empty Certificate Revocation List (CRL) do:
</p>
<div class="example">
<pre class="example-preformatted">$ certtool --generate-crl --load-ca-privkey x509-ca-key.pem \
           --load-ca-certificate x509-ca.pem
</pre></div>

<p>To create a CRL that contains some revoked certificates, place the
certificates in a file and use <code class="code">--load-certificate</code> as follows:
</p>
<div class="example">
<pre class="example-preformatted">$ certtool --generate-crl --load-ca-privkey x509-ca-key.pem \
  --load-ca-certificate x509-ca.pem --load-certificate revoked-certs.pem
</pre></div>

<p>To verify a Certificate Revocation List (CRL) do:
</p>
<div class="example">
<pre class="example-preformatted">$ certtool --verify-crl --load-ca-certificate x509-ca.pem &lt; crl.pem
</pre></div>
<a class="anchor" id="certtool-Files"></a><h4 class="subsubheading" id="certtool-Files-1"><span>certtool Files<a class="copiable-link" href="#certtool-Files-1"> &para;</a></span></h4>
<h4 class="subsubheading" id="Certtool_0027s-template-file-format"><span>Certtool&rsquo;s template file format<a class="copiable-link" href="#Certtool_0027s-template-file-format"> &para;</a></span></h4>
<p>A template file can be used to avoid the interactive questions of
certtool. Initially create a file named &rsquo;cert.cfg&rsquo; that contains the information
about the certificate. The template can be used as below:
</p>
<div class="example">
<pre class="example-preformatted">$ certtool --generate-certificate --load-privkey key.pem  \
   --template cert.cfg --outfile cert.pem \
   --load-ca-certificate ca-cert.pem --load-ca-privkey ca-key.pem
</pre></div>

<p>An example certtool template file that can be used to generate a certificate
request or a self signed certificate follows.
</p>
<div class="example">
<pre class="example-preformatted"># X.509 Certificate options
#
# DN options

# The organization of the subject.
organization = &quot;Koko inc.&quot;

# The organizational unit of the subject.
unit = &quot;sleeping dept.&quot;

# The locality of the subject.
# locality =

# The state of the certificate owner.
state = &quot;Attiki&quot;

# The country of the subject. Two letter code.
country = GR

# The common name of the certificate owner.
cn = &quot;Cindy Lauper&quot;

# A user id of the certificate owner.
#uid = &quot;clauper&quot;

# Set domain components
#dc = &quot;name&quot;
#dc = &quot;domain&quot;

# If the supported DN OIDs are not adequate you can set
# any OID here.
# For example set the X.520 Title and the X.520 Pseudonym
# by using OID and string pairs.
#dn_oid = &quot;2.5.4.12 Dr.&quot;
#dn_oid = &quot;2.5.4.65 jackal&quot;

# This is deprecated and should not be used in new
# certificates.
# pkcs9_email = &quot;none@none.org&quot;

# An alternative way to set the certificate's distinguished name directly
# is with the &quot;dn&quot; option. The attribute names allowed are:
# C (country), street, O (organization), OU (unit), title, CN (common name),
# L (locality), ST (state), placeOfBirth, gender, countryOfCitizenship, 
# countryOfResidence, serialNumber, telephoneNumber, surName, initials, 
# generationQualifier, givenName, pseudonym, dnQualifier, postalCode, name, 
# businessCategory, DC, UID, jurisdictionOfIncorporationLocalityName, 
# jurisdictionOfIncorporationStateOrProvinceName,
# jurisdictionOfIncorporationCountryName, XmppAddr, and numeric OIDs.

#dn = &quot;cn = Nikos,st = New\, Something,C=GR,surName=Mavrogiannopoulos,2.5.4.9=Arkadias&quot;

# The serial number of the certificate
# The value is in decimal (i.e. 1963) or hex (i.e. 0x07ab).
# Comment the field for a random serial number.
serial = 007

# In how many days, counting from today, this certificate will expire.
# Use -1 if there is no expiration date.
expiration_days = 700

# Alternatively you may set concrete dates and time. The GNU date string 
# formats are accepted. See:
# https://www.gnu.org/software/tar/manual/html_node/Date-input-formats.html

#activation_date = &quot;2004-02-29 16:21:42&quot;
#expiration_date = &quot;2025-02-29 16:24:41&quot;

# X.509 v3 extensions

# A dnsname in case of a WWW server.
#dns_name = &quot;www.none.org&quot;
#dns_name = &quot;www.morethanone.org&quot;

# An othername defined by an OID and a hex encoded string
#other_name = &quot;1.3.6.1.5.2.2 302ca00d1b0b56414e5245494e2e4f5247a11b3019a006020400000002a10f300d1b047269636b1b0561646d696e&quot;
#other_name_utf8 = &quot;1.2.4.5.6 A UTF8 string&quot;
#other_name_octet = &quot;1.2.4.5.6 A string that will be encoded as ASN.1 octet string&quot;

# Allows writing an XmppAddr Identifier
#xmpp_name = juliet@im.example.com

# Names used in PKINIT
#krb5_principal = user@REALM.COM
#krb5_principal = HTTP/user@REALM.COM

# A subject alternative name URI
#uri = &quot;https://www.example.com&quot;

# An IP address in case of a server.
#ip_address = &quot;192.168.1.1&quot;

# An email in case of a person
email = &quot;none@none.org&quot;

# TLS feature (rfc7633) extension. That can is used to indicate mandatory TLS
# extension features to be provided by the server. In practice this is used
# to require the Status Request (extid: 5) extension from the server. That is,
# to require the server holding this certificate to provide a stapled OCSP response.
# You can have multiple lines for multiple TLS features.

# To ask for OCSP status request use:
#tls_feature = 5

# Challenge password used in certificate requests
challenge_password = 123456

# Password when encrypting a private key
#password = secret

# An URL that has CRLs (certificate revocation lists)
# available. Needed in CA certificates.
#crl_dist_points = &quot;https://www.getcrl.crl/getcrl/&quot;

# Whether this is a CA certificate or not
#ca

# Subject Unique ID (in hex)
#subject_unique_id = 00153224

# Issuer Unique ID (in hex)
#issuer_unique_id = 00153225

#### Key usage

# The following key usage flags are used by CAs and end certificates

# Whether this certificate will be used to sign data (needed
# in TLS DHE ciphersuites). This is the digitalSignature flag
# in RFC5280 terminology.
signing_key

# Whether this certificate will be used to encrypt data (needed
# in TLS RSA ciphersuites). Note that it is preferred to use different
# keys for encryption and signing. This is the keyEncipherment flag
# in RFC5280 terminology.
encryption_key

# Whether this key will be used to sign other certificates. The
# keyCertSign flag in RFC5280 terminology.
#cert_signing_key

# Whether this key will be used to sign CRLs. The
# cRLSign flag in RFC5280 terminology.
#crl_signing_key

# The keyAgreement flag of RFC5280. Its purpose is loosely
# defined. Not use it unless required by a protocol.
#key_agreement

# The dataEncipherment flag of RFC5280. Its purpose is loosely
# defined. Not use it unless required by a protocol.
#data_encipherment

# The nonRepudiation flag of RFC5280. Its purpose is loosely
# defined. Not use it unless required by a protocol.
#non_repudiation

#### Extended key usage (key purposes)

# The following extensions are used in an end certificate
# to clarify its purpose. Some CAs also use it to indicate
# the types of certificates they are purposed to sign.


# Whether this certificate will be used for a TLS client;
# this sets the id-kp-clientAuth (1.3.6.1.5.5.7.3.2) of
# extended key usage.
#tls_www_client

# Whether this certificate will be used for a TLS server;
# this sets the id-kp-serverAuth (1.3.6.1.5.5.7.3.1) of
# extended key usage.
#tls_www_server

# Whether this key will be used to sign code. This sets the
# id-kp-codeSigning (1.3.6.1.5.5.7.3.3) of extended key usage
# extension.
#code_signing_key

# Whether this key will be used to sign OCSP data. This sets the
# id-kp-OCSPSigning (1.3.6.1.5.5.7.3.9) of extended key usage extension.
#ocsp_signing_key

# Whether this key will be used for time stamping. This sets the
# id-kp-timeStamping (1.3.6.1.5.5.7.3.8) of extended key usage extension.
#time_stamping_key

# Whether this key will be used for email protection. This sets the
# id-kp-emailProtection (1.3.6.1.5.5.7.3.4) of extended key usage extension.
#email_protection_key

# Whether this key will be used for IPsec IKE operations (1.3.6.1.5.5.7.3.17).
#ipsec_ike_key

## adding custom key purpose OIDs

# for microsoft smart card logon
# key_purpose_oid = 1.3.6.1.4.1.311.20.2.2

# for email protection
# key_purpose_oid = 1.3.6.1.5.5.7.3.4

# for any purpose (must not be used in intermediate CA certificates)
# key_purpose_oid = 2.5.29.37.0

### end of key purpose OIDs

### Adding arbitrary extensions
# This requires to provide the extension OIDs, as well as the extension data in
# hex format. The following two options are available since GnuTLS 3.5.3.
#add_extension = &quot;1.2.3.4 0x0AAB01ACFE&quot;

# As above but encode the data as an octet string
#add_extension = &quot;1.2.3.4 octet_string(0x0AAB01ACFE)&quot;

# For portability critical extensions shouldn't be set to certificates.
#add_critical_extension = &quot;5.6.7.8 0x1AAB01ACFE&quot;

# When generating a certificate from a certificate
# request, then honor the extensions stored in the request
# and store them in the real certificate.
#honor_crq_extensions

# Alternatively only specific extensions can be copied.
#honor_crq_ext = 2.5.29.17
#honor_crq_ext = 2.5.29.15

# Path length constraint. Sets the maximum number of
# certificates that can be used to certify this certificate.
# (i.e. the certificate chain length)
#path_len = -1
#path_len = 2

# OCSP URI
# ocsp_uri = https://my.ocsp.server/ocsp

# CA issuers URI
# ca_issuers_uri = https://my.ca.issuer

# Certificate policies
#policy1 = 1.3.6.1.4.1.5484.1.10.99.1.0
#policy1_txt = &quot;This is a long policy to summarize&quot;
#policy1_url = https://www.example.com/a-policy-to-read

#policy2 = 1.3.6.1.4.1.5484.1.10.99.1.1
#policy2_txt = &quot;This is a short policy&quot;
#policy2_url = https://www.example.com/another-policy-to-read

# The number of additional certificates that may appear in a
# path before the anyPolicy is no longer acceptable.
#inhibit_anypolicy_skip_certs 1

# Name constraints

# DNS
#nc_permit_dns = example.com
#nc_exclude_dns = test.example.com

# EMAIL
#nc_permit_email = &quot;nmav@ex.net&quot;

# Exclude subdomains of example.com
#nc_exclude_email = .example.com

# Exclude all e-mail addresses of example.com
#nc_exclude_email = example.com

# IP
#nc_permit_ip = 192.168.0.0/16
#nc_exclude_ip = 192.168.5.0/24
#nc_permit_ip = fc0a:eef2:e7e7:a56e::/64


# Options for proxy certificates
#proxy_policy_language = 1.3.6.1.5.5.7.21.1


# Options for generating a CRL

# The number of days the next CRL update will be due.
# next CRL update will be in 43 days
#crl_next_update = 43

# this is the 5th CRL by this CA
# The value is in decimal (i.e. 1963) or hex (i.e. 0x07ab).
# Comment the field for a time-based number.
# Time-based CRL numbers generated in GnuTLS 3.6.3 and later
# are significantly larger than those generated in previous
# versions. Since CRL numbers need to be monotonic, you need
# to specify the CRL number here manually if you intend to
# downgrade to an earlier version than 3.6.3 after publishing
# the CRL as it is not possible to specify CRL numbers greater
# than 2**63-2 using hex notation in those versions.
#crl_number = 5

# Specify the update dates more precisely.
#crl_this_update_date = &quot;2004-02-29 16:21:42&quot;
#crl_next_update_date = &quot;2025-02-29 16:24:41&quot;

# The date that the certificates will be made seen as
# being revoked.
#crl_revocation_date = &quot;2025-02-29 16:24:41&quot;

</pre></div>


<hr>
</div>
<div class="subsection-level-extent" id="ocsptool-Invocation">
<div class="nav-panel">
<p>
Next: <a href="#danetool-Invocation" accesskey="n" rel="next">Invoking danetool</a>, Previous: <a href="#certtool-Invocation" accesskey="p" rel="prev">Invoking certtool</a>, Up: <a href="#More-on-certificate-authentication" accesskey="u" rel="up">More on certificate authentication</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Invoking-ocsptool"><span>4.2.7 Invoking ocsptool<a class="copiable-link" href="#Invoking-ocsptool"> &para;</a></span></h4>
<a class="index-entry-id" id="index-ocsptool"></a>

<h4 class="subheading" id="On-verification"><span>On verification<a class="copiable-link" href="#On-verification"> &para;</a></span></h4>
<p>Responses are typically signed/issued by designated certificates or
certificate authorities and thus this tool requires on verification
the certificate of the issuer or the full certificate chain in order to
determine the appropriate signing authority. The specified certificate
of the issuer is assumed trusted.
</p>

<a class="anchor" id="ocsptool-usage"></a><h4 class="subsubheading" id="ocsptool-help_002fusage-_0028_002d_003f_0029"><span>ocsptool help/usage (<samp class="option">-?</samp>)<a class="copiable-link" href="#ocsptool-help_002fusage-_0028_002d_003f_0029"> &para;</a></span></h4>
<a class="index-entry-id" id="index-ocsptool-help"></a>

<p>The text printed is the same whether selected with the <code class="code">help</code> option
(<samp class="option">--help</samp>) or the <code class="code">more-help</code> option (<samp class="option">--more-help</samp>).  <code class="code">more-help</code> will print
the usage text by passing it through a pager program.
<code class="code">more-help</code> is disabled on platforms without a working
<code class="code">fork(2)</code> function.  The <code class="code">PAGER</code> environment variable is
used to select the program, defaulting to <samp class="file">more</samp>.  Both will exit
with a status code of 0.
</p>
<div class="example">
<pre class="example-preformatted">ocsptool - GnuTLS OCSP tool
Usage:  ocsptool [ -&lt;flag&gt; [&lt;val&gt;] | --&lt;name&gt;[{=| }&lt;val&gt;] ]... 

None:

   -d, --debug=num            Enable debugging
				- it must be in the range:
				  0 to 9999
   -V, --verbose              More verbose output
       --infile=file          Input file
				- file must pre-exist
       --outfile=str          Output file
       --ask[=str]            Ask an OCSP/HTTP server on a certificate validity
   -e, --verify-response      Verify response
   -i, --request-info         Print information on a OCSP request
   -j, --response-info        Print information on a OCSP response
   -q, --generate-request     Generates an OCSP request
       --nonce                Use (or not) a nonce to OCSP request
       --load-chain=file      Reads a set of certificates forming a chain from file
				- file must pre-exist
       --load-issuer=file     Reads issuer's certificate from file
				- file must pre-exist
       --load-cert=file       Reads the certificate to check from file
				- file must pre-exist
       --load-trust=file      Read OCSP trust anchors from file
				- prohibits the option 'load-signer'
				- file must pre-exist
       --load-signer=file     Reads the OCSP response signer from file
				- prohibits the option 'load-trust'
				- file must pre-exist
       --inder                Use DER format for input certificates and private keys
       --outder               Use DER format for output of responses (this is the default)
       --outpem               Use PEM format for output of responses
   -Q, --load-request=file    Reads the DER encoded OCSP request from file
				- file must pre-exist
   -S, --load-response=file   Reads the DER encoded OCSP response from file
				- file must pre-exist
       --ignore-errors        Ignore any verification errors
       --verify-allow-broken  Allow broken algorithms, such as MD5 for verification
       --attime=str           Perform validation at the timestamp instead of the system time

Version, usage and configuration options:

   -v, --version[=arg]        output version information and exit
   -h, --help                 display extended usage information and exit
   -!, --more-help            extended usage information passed thru pager

Options are specified by doubled hyphens and their name or by a single
hyphen and the flag character.

ocsptool is a program that can parse and print information about
OCSP requests/responses, generate requests and verify responses. Unlike
other GnuTLS applications it outputs DER encoded structures by default
unless the '--outpem' option is specified.

Please send bug reports to:  &lt;bugs@gnutls.org&gt;

</pre></div>

<h4 class="subsubheading" id="debug-option-_0028_002dd_0029_002e-4"><span>debug option (-d).<a class="copiable-link" href="#debug-option-_0028_002dd_0029_002e-4"> &para;</a></span></h4>
<a class="anchor" id="ocsptool-debug"></a>
<p>This is the &ldquo;enable debugging&rdquo; option.
This option takes a ArgumentType.NUMBER argument.
Specifies the debug level.
</p><h4 class="subsubheading" id="ask-option_002e"><span>ask option.<a class="copiable-link" href="#ask-option_002e"> &para;</a></span></h4>
<a class="anchor" id="ocsptool-ask"></a>
<p>This is the &ldquo;ask an ocsp/http server on a certificate validity&rdquo; option.
This option takes a ArgumentType.STRING argument <samp class="file">server name|url</samp>.
Connects to the specified HTTP OCSP server and queries on the validity of the loaded certificate.
Its argument can be a URL or a plain server name. It can be combined with &ndash;load-chain, where it checks
all certificates in the provided chain, or with &ndash;load-cert and
&ndash;load-issuer options. The latter checks the provided certificate
against its specified issuer certificate.
</p><h4 class="subsubheading" id="verify_002dresponse-option-_0028_002de_0029_002e"><span>verify-response option (-e).<a class="copiable-link" href="#verify_002dresponse-option-_0028_002de_0029_002e"> &para;</a></span></h4>
<a class="anchor" id="ocsptool-verify_002dresponse"></a>
<p>This is the &ldquo;verify response&rdquo; option.
Verifies the provided OCSP response against the system trust
anchors (unless &ndash;load-trust is provided). It requires the &ndash;load-signer
or &ndash;load-chain options to obtain the signer of the OCSP response.
</p><h4 class="subsubheading" id="request_002dinfo-option-_0028_002di_0029_002e"><span>request-info option (-i).<a class="copiable-link" href="#request_002dinfo-option-_0028_002di_0029_002e"> &para;</a></span></h4>
<a class="anchor" id="ocsptool-request_002dinfo"></a>
<p>This is the &ldquo;print information on a ocsp request&rdquo; option.
Display detailed information on the provided OCSP request.
</p><h4 class="subsubheading" id="response_002dinfo-option-_0028_002dj_0029_002e"><span>response-info option (-j).<a class="copiable-link" href="#response_002dinfo-option-_0028_002dj_0029_002e"> &para;</a></span></h4>
<a class="anchor" id="ocsptool-response_002dinfo"></a>
<p>This is the &ldquo;print information on a ocsp response&rdquo; option.
Display detailed information on the provided OCSP response.
</p><h4 class="subsubheading" id="load_002dtrust-option_002e"><span>load-trust option.<a class="copiable-link" href="#load_002dtrust-option_002e"> &para;</a></span></h4>
<a class="anchor" id="ocsptool-load_002dtrust"></a>
<p>This is the &ldquo;read ocsp trust anchors from file&rdquo; option.
This option takes a ArgumentType.FILE argument.
</p>
<p>This option has some usage constraints.  It:
</p><ul class="itemize mark-bullet">
<li>must not appear in combination with any of the following options:
load-signer.
</li></ul>

<p>When verifying an OCSP response read the trust anchors from the
provided file. When this is not provided, the system&rsquo;s trust anchors will be
used.
</p><h4 class="subsubheading" id="outder-option_002e-1"><span>outder option.<a class="copiable-link" href="#outder-option_002e-1"> &para;</a></span></h4>
<a class="anchor" id="ocsptool-outder"></a>
<p>This is the &ldquo;use der format for output of responses (this is the default)&rdquo; option.
The output will be in DER encoded format. Unlike other GnuTLS tools, this is the default for this tool
</p><h4 class="subsubheading" id="outpem-option_002e"><span>outpem option.<a class="copiable-link" href="#outpem-option_002e"> &para;</a></span></h4>
<a class="anchor" id="ocsptool-outpem"></a>
<p>This is the &ldquo;use pem format for output of responses&rdquo; option.
The output will be in PEM format.
</p><h4 class="subsubheading" id="verify_002dallow_002dbroken-option_002e-1"><span>verify-allow-broken option.<a class="copiable-link" href="#verify_002dallow_002dbroken-option_002e-1"> &para;</a></span></h4>
<a class="anchor" id="ocsptool-verify_002dallow_002dbroken"></a>
<p>This is the &ldquo;allow broken algorithms, such as md5 for verification&rdquo; option.
This can be combined with &ndash;verify-response.
</p><h4 class="subsubheading" id="attime-option_002e-4"><span>attime option.<a class="copiable-link" href="#attime-option_002e-4"> &para;</a></span></h4>
<a class="anchor" id="ocsptool-attime"></a>
<p>This is the &ldquo;perform validation at the timestamp instead of the system time&rdquo; option.
This option takes a ArgumentType.STRING argument <samp class="file">timestamp</samp>.
timestamp is an instance in time encoded as Unix time or in a human
 readable timestring such as &quot;29 Feb 2004&quot;, &quot;2004-02-29&quot;.
Full documentation available at 
&lt;https://www.gnu.org/software/coreutils/manual/html_node/Date-input-formats.html&gt;
or locally via info &rsquo;(coreutils) date invocation&rsquo;.
</p><h4 class="subsubheading" id="version-option-_0028_002dv_0029_002e-4"><span>version option (-v).<a class="copiable-link" href="#version-option-_0028_002dv_0029_002e-4"> &para;</a></span></h4>
<a class="anchor" id="ocsptool-version"></a>
<p>This is the &ldquo;output version information and exit&rdquo; option.
This option takes a ArgumentType.KEYWORD argument.
Output version of program and exit.  The default mode is &lsquo;v&rsquo;, a simple
version.  The &lsquo;c&rsquo; mode will print copyright information and &lsquo;n&rsquo; will
print the full copyright notice.
</p><h4 class="subsubheading" id="help-option-_0028_002dh_0029_002e-4"><span>help option (-h).<a class="copiable-link" href="#help-option-_0028_002dh_0029_002e-4"> &para;</a></span></h4>
<a class="anchor" id="ocsptool-help"></a>
<p>This is the &ldquo;display extended usage information and exit&rdquo; option.
Display usage information and exit.
</p><h4 class="subsubheading" id="more_002dhelp-option-_0028_002d_0021_0029_002e-4"><span>more-help option (-!).<a class="copiable-link" href="#more_002dhelp-option-_0028_002d_0021_0029_002e-4"> &para;</a></span></h4>
<a class="anchor" id="ocsptool-more_002dhelp"></a>
<p>This is the &ldquo;extended usage information passed thru pager&rdquo; option.
Pass the extended usage information through a pager.
<a class="anchor" id="ocsptool-exit-status"></a></p><h4 class="subsubheading" id="ocsptool-exit-status-1"><span>ocsptool exit status<a class="copiable-link" href="#ocsptool-exit-status-1"> &para;</a></span></h4>

<p>One of the following exit values will be returned:
</p><dl class="table">
<dt>&lsquo;<samp class="samp">0 (EXIT_SUCCESS)</samp>&rsquo;</dt>
<dd><p>Successful program execution.
</p></dd>
<dt>&lsquo;<samp class="samp">1 (EXIT_FAILURE)</samp>&rsquo;</dt>
<dd><p>The operation failed or the command syntax was not valid.
</p></dd>
</dl>
<a class="anchor" id="ocsptool-See-Also"></a><h4 class="subsubheading" id="ocsptool-See-Also-1"><span>ocsptool See Also<a class="copiable-link" href="#ocsptool-See-Also-1"> &para;</a></span></h4>
<p>certtool (1)
<a class="anchor" id="ocsptool-Examples"></a></p><h4 class="subsubheading" id="ocsptool-Examples-1"><span>ocsptool Examples<a class="copiable-link" href="#ocsptool-Examples-1"> &para;</a></span></h4>
<h4 class="subsubheading" id="Print-information-about-an-OCSP-request"><span>Print information about an OCSP request<a class="copiable-link" href="#Print-information-about-an-OCSP-request"> &para;</a></span></h4>

<p>To parse an OCSP request and print information about the content, the
<code class="code">-i</code> or <code class="code">--request-info</code> parameter may be used as follows.
The <code class="code">-Q</code> parameter specify the name of the file containing the
OCSP request, and it should contain the OCSP request in binary DER
format.
</p>
<div class="example">
<pre class="example-preformatted">$ ocsptool -i -Q ocsp-request.der
</pre></div>

<p>The input file may also be sent to standard input like this:
</p>
<div class="example">
<pre class="example-preformatted">$ cat ocsp-request.der | ocsptool --request-info
</pre></div>

<h4 class="subsubheading" id="Print-information-about-an-OCSP-response"><span>Print information about an OCSP response<a class="copiable-link" href="#Print-information-about-an-OCSP-response"> &para;</a></span></h4>

<p>Similar to parsing OCSP requests, OCSP responses can be parsed using
the <code class="code">-j</code> or <code class="code">--response-info</code> as follows.
</p>
<div class="example">
<pre class="example-preformatted">$ ocsptool -j -Q ocsp-response.der
$ cat ocsp-response.der | ocsptool --response-info
</pre></div>

<h4 class="subsubheading" id="Generate-an-OCSP-request"><span>Generate an OCSP request<a class="copiable-link" href="#Generate-an-OCSP-request"> &para;</a></span></h4>

<p>The <code class="code">-q</code> or <code class="code">--generate-request</code> parameters are used to
generate an OCSP request.  By default the OCSP request is written to
standard output in binary DER format, but can be stored in a file
using <code class="code">--outfile</code>.  To generate an OCSP request the issuer of the
certificate to check needs to be specified with <code class="code">--load-issuer</code>
and the certificate to check with <code class="code">--load-cert</code>.  By default PEM
format is used for these files, although <code class="code">--inder</code> can be used to
specify that the input files are in DER format.
</p>
<div class="example">
<pre class="example-preformatted">$ ocsptool -q --load-issuer issuer.pem --load-cert client.pem \
           --outfile ocsp-request.der
</pre></div>

<p>When generating OCSP requests, the tool will add an OCSP extension
containing a nonce.  This behaviour can be disabled by specifying
<code class="code">--no-nonce</code>.
</p>
<h4 class="subsubheading" id="Verify-signature-in-OCSP-response"><span>Verify signature in OCSP response<a class="copiable-link" href="#Verify-signature-in-OCSP-response"> &para;</a></span></h4>

<p>To verify the signature in an OCSP response the <code class="code">-e</code> or
<code class="code">--verify-response</code> parameter is used.  The tool will read an
OCSP response in DER format from standard input, or from the file
specified by <code class="code">--load-response</code>.  The OCSP response is verified
against a set of trust anchors, which are specified using
<code class="code">--load-trust</code>.  The trust anchors are concatenated certificates
in PEM format.  The certificate that signed the OCSP response needs to
be in the set of trust anchors, or the issuer of the signer
certificate needs to be in the set of trust anchors and the OCSP
Extended Key Usage bit has to be asserted in the signer certificate.
</p>
<div class="example">
<pre class="example-preformatted">$ ocsptool -e --load-trust issuer.pem \
           --load-response ocsp-response.der
</pre></div>

<p>The tool will print status of verification.
</p>
<h4 class="subsubheading" id="Verify-signature-in-OCSP-response-against-given-certificate"><span>Verify signature in OCSP response against given certificate<a class="copiable-link" href="#Verify-signature-in-OCSP-response-against-given-certificate"> &para;</a></span></h4>

<p>It is possible to override the normal trust logic if you know that a
certain certificate is supposed to have signed the OCSP response, and
you want to use it to check the signature.  This is achieved using
<code class="code">--load-signer</code> instead of <code class="code">--load-trust</code>.  This will load
one certificate and it will be used to verify the signature in the
OCSP response.  It will not check the Extended Key Usage bit.
</p>
<div class="example">
<pre class="example-preformatted">$ ocsptool -e --load-signer ocsp-signer.pem \
           --load-response ocsp-response.der
</pre></div>

<p>This approach is normally only relevant in two situations.  The first
is when the OCSP response does not contain a copy of the signer
certificate, so the <code class="code">--load-trust</code> code would fail.  The second
is if you want to avoid the indirect mode where the OCSP response
signer certificate is signed by a trust anchor.
</p>
<h4 class="subsubheading" id="Real_002dworld-example"><span>Real-world example<a class="copiable-link" href="#Real_002dworld-example"> &para;</a></span></h4>

<p>Here is an example of how to generate an OCSP request for a
certificate and to verify the response.  For illustration we&rsquo;ll use
the <code class="code">blog.josefsson.org</code> host, which (as of writing) uses a
certificate from CACert.  First we&rsquo;ll use <code class="code">gnutls-cli</code> to get a
copy of the server certificate chain.  The server is not required to
send this information, but this particular one is configured to do so.
</p>
<div class="example">
<pre class="example-preformatted">$ echo | gnutls-cli -p 443 blog.josefsson.org --save-cert chain.pem
</pre></div>

<p>The saved certificates normally contain a pointer to where the OCSP
responder is located, in the Authority Information Access Information
extension.  For example, from <code class="code">certtool -i &lt; chain.pem</code> there is
this information:
</p>
<div class="example">
<pre class="example-preformatted">		Authority Information Access Information (not critical):
			Access Method: 1.3.6.1.5.5.7.48.1 (id-ad-ocsp)
			Access Location URI: https://ocsp.CAcert.org/
</pre></div>

<p>This means that ocsptool can discover the servers to contact over HTTP.
We can now request information on the chain certificates.
</p>
<div class="example">
<pre class="example-preformatted">$ ocsptool --ask --load-chain chain.pem
</pre></div>

<p>The request is sent via HTTP to the OCSP server address found in
the certificates. It is possible to override the address of the
OCSP server as well as ask information on a particular certificate
using &ndash;load-cert and &ndash;load-issuer.
</p>
<div class="example">
<pre class="example-preformatted">$ ocsptool --ask https://ocsp.CAcert.org/ --load-chain chain.pem
</pre></div>


<hr>
</div>
<div class="subsection-level-extent" id="danetool-Invocation">
<div class="nav-panel">
<p>
Previous: <a href="#ocsptool-Invocation" accesskey="p" rel="prev">Invoking ocsptool</a>, Up: <a href="#More-on-certificate-authentication" accesskey="u" rel="up">More on certificate authentication</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Invoking-danetool"><span>4.2.8 Invoking danetool<a class="copiable-link" href="#Invoking-danetool"> &para;</a></span></h4>
<a class="index-entry-id" id="index-danetool"></a>

<p>Tool to generate and check DNS resource records for the DANE protocol.
</p>
<a class="anchor" id="danetool-usage"></a><h4 class="subsubheading" id="danetool-help_002fusage-_0028_002d_003f_0029"><span>danetool help/usage (<samp class="option">-?</samp>)<a class="copiable-link" href="#danetool-help_002fusage-_0028_002d_003f_0029"> &para;</a></span></h4>
<a class="index-entry-id" id="index-danetool-help"></a>

<p>The text printed is the same whether selected with the <code class="code">help</code> option
(<samp class="option">--help</samp>) or the <code class="code">more-help</code> option (<samp class="option">--more-help</samp>).  <code class="code">more-help</code> will print
the usage text by passing it through a pager program.
<code class="code">more-help</code> is disabled on platforms without a working
<code class="code">fork(2)</code> function.  The <code class="code">PAGER</code> environment variable is
used to select the program, defaulting to <samp class="file">more</samp>.  Both will exit
with a status code of 0.
</p>
<div class="example">
<pre class="example-preformatted">danetool - GnuTLS DANE tool
Usage:  danetool [ -&lt;flag&gt; [&lt;val&gt;] | --&lt;name&gt;[{=| }&lt;val&gt;] ]... 

None:

   -d, --debug=num            Enable debugging
				- it must be in the range:
				  0 to 9999
   -V, --verbose              More verbose output
       --outfile=str          Output file
       --load-pubkey=str      Loads a public key file
       --load-certificate=str Loads a certificate file
       --dlv=str              Sets a DLV file
       --hash=str             Hash algorithm to use for signing
       --check=str            Check a host's DANE TLSA entry
       --check-ee             Check only the end-entity's certificate
       --check-ca             Check only the CA's certificate
       --tlsa-rr              Print the DANE RR data on a certificate or public key
				- requires the option 'host'
       --host=str             Specify the hostname to be used in the DANE RR
       --proto=str            The protocol set for DANE data (tcp, udp etc.)
       --port=str             The port or service to connect to, for DANE data
       --app-proto            an alias for the 'starttls-proto' option
       --starttls-proto=str   The application protocol to be used to obtain the server's certificate (https, ftp, smtp, imap, ldap, xmpp, lmtp, pop3, nntp, sieve, postgres)
       --ca                   Whether the provided certificate or public key is a Certificate Authority
       --x509                 Use the hash of the X.509 certificate, rather than the public key
       --local                an alias for the 'domain' option
       --domain               The provided certificate or public key is issued by the local domain
				- enabled by default
				- disabled as '--no-domain'
       --local-dns            Use the local DNS server for DNSSEC resolving
       --insecure             Do not verify any DNSSEC signature
       --inder                Use DER format for input certificates and private keys
       --inraw                an alias for the 'inder' option
       --print-raw            Print the received DANE data in raw format
       --quiet                Suppress several informational messages

Version, usage and configuration options:

   -v, --version[=arg]        output version information and exit
   -h, --help                 display extended usage information and exit
   -!, --more-help            extended usage information passed thru pager

Options are specified by doubled hyphens and their name or by a single
hyphen and the flag character.

Tool to generate and check DNS resource records for the DANE protocol.

Please send bug reports to:  &lt;bugs@gnutls.org&gt;

</pre></div>

<h4 class="subsubheading" id="debug-option-_0028_002dd_0029_002e-5"><span>debug option (-d).<a class="copiable-link" href="#debug-option-_0028_002dd_0029_002e-5"> &para;</a></span></h4>
<a class="anchor" id="danetool-debug"></a>
<p>This is the &ldquo;enable debugging&rdquo; option.
This option takes a ArgumentType.NUMBER argument.
Specifies the debug level.
</p><h4 class="subsubheading" id="load_002dpubkey-option_002e-1"><span>load-pubkey option.<a class="copiable-link" href="#load_002dpubkey-option_002e-1"> &para;</a></span></h4>
<a class="anchor" id="danetool-load_002dpubkey"></a>
<p>This is the &ldquo;loads a public key file&rdquo; option.
This option takes a ArgumentType.STRING argument.
This can be either a file or a PKCS #11 URL
</p><h4 class="subsubheading" id="load_002dcertificate-option_002e-1"><span>load-certificate option.<a class="copiable-link" href="#load_002dcertificate-option_002e-1"> &para;</a></span></h4>
<a class="anchor" id="danetool-load_002dcertificate"></a>
<p>This is the &ldquo;loads a certificate file&rdquo; option.
This option takes a ArgumentType.STRING argument.
This can be either a file or a PKCS #11 URL
</p><h4 class="subsubheading" id="dlv-option_002e"><span>dlv option.<a class="copiable-link" href="#dlv-option_002e"> &para;</a></span></h4>
<a class="anchor" id="danetool-dlv"></a>
<p>This is the &ldquo;sets a dlv file&rdquo; option.
This option takes a ArgumentType.STRING argument.
This sets a DLV file to be used for DNSSEC verification.
</p><h4 class="subsubheading" id="hash-option_002e-1"><span>hash option.<a class="copiable-link" href="#hash-option_002e-1"> &para;</a></span></h4>
<a class="anchor" id="danetool-hash"></a>
<p>This is the &ldquo;hash algorithm to use for signing&rdquo; option.
This option takes a ArgumentType.STRING argument.
Available hash functions are SHA1, RMD160, SHA256, SHA384, SHA512.
</p><h4 class="subsubheading" id="check-option_002e"><span>check option.<a class="copiable-link" href="#check-option_002e"> &para;</a></span></h4>
<a class="anchor" id="danetool-check"></a>
<p>This is the &ldquo;check a host&rsquo;s dane tlsa entry&rdquo; option.
This option takes a ArgumentType.STRING argument.
Obtains the DANE TLSA entry from the given hostname and prints information. Note that the actual certificate of the host can be provided using &ndash;load-certificate, otherwise danetool will connect to the server to obtain it. The exit code on verification success will be zero.
</p><h4 class="subsubheading" id="check_002dee-option_002e"><span>check-ee option.<a class="copiable-link" href="#check_002dee-option_002e"> &para;</a></span></h4>
<a class="anchor" id="danetool-check_002dee"></a>
<p>This is the &ldquo;check only the end-entity&rsquo;s certificate&rdquo; option.
Checks the end-entity&rsquo;s certificate only. Trust anchors or CAs are not considered.
</p><h4 class="subsubheading" id="check_002dca-option_002e"><span>check-ca option.<a class="copiable-link" href="#check_002dca-option_002e"> &para;</a></span></h4>
<a class="anchor" id="danetool-check_002dca"></a>
<p>This is the &ldquo;check only the ca&rsquo;s certificate&rdquo; option.
Checks the trust anchor&rsquo;s and CA&rsquo;s certificate only. End-entities are not considered.
</p><h4 class="subsubheading" id="tlsa_002drr-option_002e"><span>tlsa-rr option.<a class="copiable-link" href="#tlsa_002drr-option_002e"> &para;</a></span></h4>
<a class="anchor" id="danetool-tlsa_002drr"></a>
<p>This is the &ldquo;print the dane rr data on a certificate or public key&rdquo; option.
</p>
<p>This option has some usage constraints.  It:
</p><ul class="itemize mark-bullet">
<li>must appear in combination with the following options:
host.
</li></ul>

<p>This command prints the DANE RR data needed to enable DANE on a DNS server.
</p><h4 class="subsubheading" id="host-option_002e"><span>host option.<a class="copiable-link" href="#host-option_002e"> &para;</a></span></h4>
<a class="anchor" id="danetool-host"></a>
<p>This is the &ldquo;specify the hostname to be used in the dane rr&rdquo; option.
This option takes a ArgumentType.STRING argument <samp class="file">Hostname</samp>.
This command sets the hostname for the DANE RR.
</p><h4 class="subsubheading" id="proto-option_002e"><span>proto option.<a class="copiable-link" href="#proto-option_002e"> &para;</a></span></h4>
<a class="anchor" id="danetool-proto"></a>
<p>This is the &ldquo;the protocol set for dane data (tcp, udp etc.)&rdquo; option.
This option takes a ArgumentType.STRING argument <samp class="file">Protocol</samp>.
This command specifies the protocol for the service set in the DANE data.
</p><h4 class="subsubheading" id="app_002dproto-option_002e-2"><span>app-proto option.<a class="copiable-link" href="#app_002dproto-option_002e-2"> &para;</a></span></h4>
<a class="anchor" id="danetool-app_002dproto"></a>
<p>This is an alias for the <code class="code">starttls-proto</code> option,
see <a class="pxref" href="#danetool-starttls_002dproto">the starttls-proto option documentation</a>.
</p>
<h4 class="subsubheading" id="starttls_002dproto-option_002e-2"><span>starttls-proto option.<a class="copiable-link" href="#starttls_002dproto-option_002e-2"> &para;</a></span></h4>
<a class="anchor" id="danetool-starttls_002dproto"></a>
<p>This is the &ldquo;the application protocol to be used to obtain the server&rsquo;s certificate (https, ftp, smtp, imap, ldap, xmpp, lmtp, pop3, nntp, sieve, postgres)&rdquo; option.
This option takes a ArgumentType.STRING argument.
When the server&rsquo;s certificate isn&rsquo;t provided danetool will connect to the server to obtain the certificate. In that case it is required to know the protocol to talk with the server prior to initiating the TLS handshake.
</p><h4 class="subsubheading" id="ca-option_002e"><span>ca option.<a class="copiable-link" href="#ca-option_002e"> &para;</a></span></h4>
<a class="anchor" id="danetool-ca"></a>
<p>This is the &ldquo;whether the provided certificate or public key is a certificate authority&rdquo; option.
Marks the DANE RR as a CA certificate if specified.
</p><h4 class="subsubheading" id="x509-option_002e"><span>x509 option.<a class="copiable-link" href="#x509-option_002e"> &para;</a></span></h4>
<a class="anchor" id="danetool-x509"></a>
<p>This is the &ldquo;use the hash of the x.509 certificate, rather than the public key&rdquo; option.
This option forces the generated record to contain the hash of the full X.509 certificate. By default only the hash of the public key is used.
</p><h4 class="subsubheading" id="local-option_002e"><span>local option.<a class="copiable-link" href="#local-option_002e"> &para;</a></span></h4>
<a class="anchor" id="danetool-local"></a>
<p>This is an alias for the <code class="code">domain</code> option,
see <a class="pxref" href="#danetool-domain">the domain option documentation</a>.
</p>
<h4 class="subsubheading" id="domain-option_002e"><span>domain option.<a class="copiable-link" href="#domain-option_002e"> &para;</a></span></h4>
<a class="anchor" id="danetool-domain"></a>
<p>This is the &ldquo;the provided certificate or public key is issued by the local domain&rdquo; option.
</p>
<p>This option has some usage constraints.  It:
</p><ul class="itemize mark-bullet">
<li>can be disabled with &ndash;no-domain.
</li><li>It is enabled by default.
</li></ul>

<p>DANE distinguishes certificates and public keys offered via the DNSSEC to trusted and local entities. This flag indicates that this is a domain-issued certificate, meaning that there could be no CA involved.
</p><h4 class="subsubheading" id="local_002ddns-option_002e-1"><span>local-dns option.<a class="copiable-link" href="#local_002ddns-option_002e-1"> &para;</a></span></h4>
<a class="anchor" id="danetool-local_002ddns"></a>
<p>This is the &ldquo;use the local dns server for dnssec resolving&rdquo; option.
This option will use the local DNS server for DNSSEC.
This is disabled by default due to many servers not allowing DNSSEC.
</p><h4 class="subsubheading" id="insecure-option_002e"><span>insecure option.<a class="copiable-link" href="#insecure-option_002e"> &para;</a></span></h4>
<a class="anchor" id="danetool-insecure"></a>
<p>This is the &ldquo;do not verify any dnssec signature&rdquo; option.
Ignores any DNSSEC signature verification results.
</p><h4 class="subsubheading" id="inder-option_002e-1"><span>inder option.<a class="copiable-link" href="#inder-option_002e-1"> &para;</a></span></h4>
<a class="anchor" id="danetool-inder"></a>
<p>This is the &ldquo;use der format for input certificates and private keys&rdquo; option.
The input files will be assumed to be in DER or RAW format. 
Unlike options that in PEM input would allow multiple input data (e.g. multiple 
certificates), when reading in DER format a single data structure is read.
</p><h4 class="subsubheading" id="inraw-option_002e-1"><span>inraw option.<a class="copiable-link" href="#inraw-option_002e-1"> &para;</a></span></h4>
<a class="anchor" id="danetool-inraw"></a>
<p>This is an alias for the <code class="code">inder</code> option,
see <a class="pxref" href="#danetool-inder">the inder option documentation</a>.
</p>
<h4 class="subsubheading" id="print_002draw-option_002e"><span>print-raw option.<a class="copiable-link" href="#print_002draw-option_002e"> &para;</a></span></h4>
<a class="anchor" id="danetool-print_002draw"></a>
<p>This is the &ldquo;print the received dane data in raw format&rdquo; option.
This option will print the received DANE data.
</p><h4 class="subsubheading" id="quiet-option_002e"><span>quiet option.<a class="copiable-link" href="#quiet-option_002e"> &para;</a></span></h4>
<a class="anchor" id="danetool-quiet"></a>
<p>This is the &ldquo;suppress several informational messages&rdquo; option.
In that case on the exit code can be used as an indication of verification success
</p><h4 class="subsubheading" id="version-option-_0028_002dv_0029_002e-5"><span>version option (-v).<a class="copiable-link" href="#version-option-_0028_002dv_0029_002e-5"> &para;</a></span></h4>
<a class="anchor" id="danetool-version"></a>
<p>This is the &ldquo;output version information and exit&rdquo; option.
This option takes a ArgumentType.KEYWORD argument.
Output version of program and exit.  The default mode is &lsquo;v&rsquo;, a simple
version.  The &lsquo;c&rsquo; mode will print copyright information and &lsquo;n&rsquo; will
print the full copyright notice.
</p><h4 class="subsubheading" id="help-option-_0028_002dh_0029_002e-5"><span>help option (-h).<a class="copiable-link" href="#help-option-_0028_002dh_0029_002e-5"> &para;</a></span></h4>
<a class="anchor" id="danetool-help"></a>
<p>This is the &ldquo;display extended usage information and exit&rdquo; option.
Display usage information and exit.
</p><h4 class="subsubheading" id="more_002dhelp-option-_0028_002d_0021_0029_002e-5"><span>more-help option (-!).<a class="copiable-link" href="#more_002dhelp-option-_0028_002d_0021_0029_002e-5"> &para;</a></span></h4>
<a class="anchor" id="danetool-more_002dhelp"></a>
<p>This is the &ldquo;extended usage information passed thru pager&rdquo; option.
Pass the extended usage information through a pager.
<a class="anchor" id="danetool-exit-status"></a></p><h4 class="subsubheading" id="danetool-exit-status-1"><span>danetool exit status<a class="copiable-link" href="#danetool-exit-status-1"> &para;</a></span></h4>

<p>One of the following exit values will be returned:
</p><dl class="table">
<dt>&lsquo;<samp class="samp">0 (EXIT_SUCCESS)</samp>&rsquo;</dt>
<dd><p>Successful program execution.
</p></dd>
<dt>&lsquo;<samp class="samp">1 (EXIT_FAILURE)</samp>&rsquo;</dt>
<dd><p>The operation failed or the command syntax was not valid.
</p></dd>
</dl>
<a class="anchor" id="danetool-See-Also"></a><h4 class="subsubheading" id="danetool-See-Also-1"><span>danetool See Also<a class="copiable-link" href="#danetool-See-Also-1"> &para;</a></span></h4>
<p>certtool (1)
<a class="anchor" id="danetool-Examples"></a></p><h4 class="subsubheading" id="danetool-Examples-1"><span>danetool Examples<a class="copiable-link" href="#danetool-Examples-1"> &para;</a></span></h4>
<h4 class="subsubheading" id="DANE-TLSA-RR-generation"><span>DANE TLSA RR generation<a class="copiable-link" href="#DANE-TLSA-RR-generation"> &para;</a></span></h4>

<p>To create a DANE TLSA resource record for a certificate (or public key) 
that was issued locally and may or may not be signed by a CA use the following command.
</p><div class="example">
<pre class="example-preformatted">$ danetool --tlsa-rr --host www.example.com --load-certificate cert.pem
</pre></div>

<p>To create a DANE TLSA resource record for a CA signed certificate, which will
be marked as such use the following command.
</p><div class="example">
<pre class="example-preformatted">$ danetool --tlsa-rr --host www.example.com --load-certificate cert.pem \
  --no-domain
</pre></div>

<p>The former is useful to add in your DNS entry even if your certificate is signed 
by a CA. That way even users who do not trust your CA will be able to verify your
certificate using DANE.
</p>
<p>In order to create a record for the CA signer of your certificate use the following.
</p><div class="example">
<pre class="example-preformatted">$ danetool --tlsa-rr --host www.example.com --load-certificate cert.pem \
  --ca --no-domain
</pre></div>

<p>To read a server&rsquo;s DANE TLSA entry, use:
</p><div class="example">
<pre class="example-preformatted">$ danetool --check www.example.com --proto tcp --port 443
</pre></div>

<p>To verify an HTTPS server&rsquo;s DANE TLSA entry, use:
</p><div class="example">
<pre class="example-preformatted">$ danetool --check www.example.com --proto tcp --port 443 --load-certificate chain.pem
</pre></div>

<p>To verify an SMTP server&rsquo;s DANE TLSA entry, use:
</p><div class="example">
<pre class="example-preformatted">$ danetool --check www.example.com --proto tcp --starttls-proto=smtp --load-certificate chain.pem
</pre></div>

<hr>
</div>
</div>
<div class="section-level-extent" id="Shared_002dkey-and-anonymous-authentication">
<div class="nav-panel">
<p>
Next: <a href="#Selecting-an-appropriate-authentication-method" accesskey="n" rel="next">Selecting an appropriate authentication method</a>, Previous: <a href="#More-on-certificate-authentication" accesskey="p" rel="prev">More on certificate authentication</a>, Up: <a href="#Authentication-methods" accesskey="u" rel="up">Authentication methods</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Shared_002dkey-and-anonymous-authentication-1"><span>4.3 Shared-key and anonymous authentication<a class="copiable-link" href="#Shared_002dkey-and-anonymous-authentication-1"> &para;</a></span></h3>

<p>In addition to certificate authentication, the TLS protocol may be
used with password, shared-key and anonymous authentication methods.
The rest of this chapter discusses details of these methods.
</p>

<ul class="mini-toc">
<li><a href="#PSK-authentication" accesskey="1">PSK authentication</a></li>
<li><a href="#SRP-authentication" accesskey="2">SRP authentication</a></li>
<li><a href="#Anonymous-authentication" accesskey="3">Anonymous authentication</a></li>
</ul>
<hr>
<div class="subsection-level-extent" id="PSK-authentication">
<div class="nav-panel">
<p>
Next: <a href="#SRP-authentication" accesskey="n" rel="next">SRP authentication</a>, Up: <a href="#Shared_002dkey-and-anonymous-authentication" accesskey="u" rel="up">Shared-key and anonymous authentication</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="PSK-authentication-1"><span>4.3.1 PSK authentication<a class="copiable-link" href="#PSK-authentication-1"> &para;</a></span></h4>


<ul class="mini-toc">
<li><a href="#Authentication-using-PSK" accesskey="1">Authentication using <abbr class="acronym">PSK</abbr></a></li>
<li><a href="#psktool-Invocation" accesskey="2">Invoking psktool</a></li>
</ul>
<hr>
<div class="subsubsection-level-extent" id="Authentication-using-PSK">
<div class="nav-panel">
<p>
Next: <a href="#psktool-Invocation" accesskey="n" rel="next">Invoking psktool</a>, Up: <a href="#PSK-authentication" accesskey="u" rel="up">PSK authentication</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsubsection" id="Authentication-using-PSK-1"><span>4.3.1.1 Authentication using <abbr class="acronym">PSK</abbr><a class="copiable-link" href="#Authentication-using-PSK-1"> &para;</a></span></h4>
<a class="index-entry-id" id="index-PSK-authentication"></a>

<p>Authentication using Pre-shared keys is a method to authenticate using
usernames and binary keys. This protocol avoids making use of public
key infrastructure and expensive calculations, thus it is suitable for
constraint clients. It is available under all TLS protocol versions.
</p>
<p>The implementation in <abbr class="acronym">GnuTLS</abbr> is based on [<a class="ref" href="#TLSPSK">TLSPSK</a>].  
The supported <abbr class="acronym">PSK</abbr> key exchange methods are:
</p>
<dl class="table">
<dt><code class="code">PSK:</code></dt>
<dd><p>Authentication using the <abbr class="acronym">PSK</abbr> protocol (no forward secrecy).
</p>
</dd>
<dt><code class="code">DHE-PSK:</code></dt>
<dd><p>Authentication using the <abbr class="acronym">PSK</abbr> protocol and Diffie-Hellman key
exchange.  This method offers perfect forward secrecy.
</p>
</dd>
<dt><code class="code">ECDHE-PSK:</code></dt>
<dd><p>Authentication using the <abbr class="acronym">PSK</abbr> protocol and Elliptic curve Diffie-Hellman key
exchange.  This method offers perfect forward secrecy.
</p>
</dd>
<dt><code class="code">RSA-PSK:</code></dt>
<dd><p>Authentication using the <abbr class="acronym">PSK</abbr> protocol for the client and an RSA certificate
for the server. This is not available under TLS 1.3.
</p>
</dd>
</dl>

<p>Helper functions to generate and maintain <abbr class="acronym">PSK</abbr> keys are also included
in <abbr class="acronym">GnuTLS</abbr>.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fkey_005fgenerate">gnutls_key_generate</a> (gnutls_datum_t * <var class="var">key</var>, unsigned int <var class="var">key_size</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fhex_005fencode">gnutls_hex_encode</a> (const gnutls_datum_t * <var class="var">data</var>, char * <var class="var">result</var>, size_t * <var class="var">result_size</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fhex_005fdecode">gnutls_hex_decode</a> (const gnutls_datum_t * <var class="var">hex_data</var>, void * <var class="var">result</var>, size_t * <var class="var">result_size</var>)</code></dt>
</dl>

<hr>
</div>
<div class="subsubsection-level-extent" id="psktool-Invocation">
<div class="nav-panel">
<p>
Previous: <a href="#Authentication-using-PSK" accesskey="p" rel="prev">Authentication using <abbr class="acronym">PSK</abbr></a>, Up: <a href="#PSK-authentication" accesskey="u" rel="up">PSK authentication</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsubsection" id="Invoking-psktool"><span>4.3.1.2 Invoking psktool<a class="copiable-link" href="#Invoking-psktool"> &para;</a></span></h4>
<a class="index-entry-id" id="index-psktool"></a>

<p>Program  that generates random keys for use with TLS-PSK. The
keys are stored in hexadecimal format in a key file.
</p>
<a class="anchor" id="psktool-usage"></a><h4 class="subsubheading" id="psktool-help_002fusage-_0028_002d_003f_0029"><span>psktool help/usage (<samp class="option">-?</samp>)<a class="copiable-link" href="#psktool-help_002fusage-_0028_002d_003f_0029"> &para;</a></span></h4>
<a class="index-entry-id" id="index-psktool-help"></a>

<p>The text printed is the same whether selected with the <code class="code">help</code> option
(<samp class="option">--help</samp>) or the <code class="code">more-help</code> option (<samp class="option">--more-help</samp>).  <code class="code">more-help</code> will print
the usage text by passing it through a pager program.
<code class="code">more-help</code> is disabled on platforms without a working
<code class="code">fork(2)</code> function.  The <code class="code">PAGER</code> environment variable is
used to select the program, defaulting to <samp class="file">more</samp>.  Both will exit
with a status code of 0.
</p>
<div class="example">
<pre class="example-preformatted">psktool - GnuTLS PSK tool
Usage:  psktool [ -&lt;flag&gt; [&lt;val&gt;] | --&lt;name&gt;[{=| }&lt;val&gt;] ]... 

None:

   -d, --debug=num            Enable debugging
				- it must be in the range:
				  0 to 9999
   -s, --keysize=num          Specify the key size in bytes (default is 32-bytes or 256-bits)
				- it must be in the range:
				  0 to 512
   -u, --username=str         Specify the username to use
   -p, --pskfile=str          Specify a pre-shared key file

Version, usage and configuration options:

   -v, --version[=arg]        output version information and exit
   -h, --help                 display extended usage information and exit
   -!, --more-help            extended usage information passed thru pager

Options are specified by doubled hyphens and their name or by a single
hyphen and the flag character.

Program  that generates random keys for use with TLS-PSK. The
keys are stored in hexadecimal format in a key file.

Please send bug reports to:  &lt;bugs@gnutls.org&gt;

</pre></div>

<h4 class="subsubheading" id="debug-option-_0028_002dd_0029_002e-6"><span>debug option (-d).<a class="copiable-link" href="#debug-option-_0028_002dd_0029_002e-6"> &para;</a></span></h4>
<a class="anchor" id="psktool-debug"></a>
<p>This is the &ldquo;enable debugging&rdquo; option.
This option takes a ArgumentType.NUMBER argument.
Specifies the debug level.
</p><h4 class="subsubheading" id="pskfile-option-_0028_002dp_0029_002e"><span>pskfile option (-p).<a class="copiable-link" href="#pskfile-option-_0028_002dp_0029_002e"> &para;</a></span></h4>
<a class="anchor" id="psktool-pskfile"></a>
<p>This is the &ldquo;specify a pre-shared key file&rdquo; option.
This option takes a ArgumentType.STRING argument.
This option will specify the pre-shared key file to store the generated keys.
</p><h4 class="subsubheading" id="passwd-option_002e"><span>passwd option.<a class="copiable-link" href="#passwd-option_002e"> &para;</a></span></h4>
<a class="anchor" id="psktool-passwd"></a>
<p>This is an alias for the <code class="code">pskfile</code> option,
see <a class="pxref" href="#psktool-pskfile">the pskfile option documentation</a>.
</p>
<h4 class="subsubheading" id="version-option-_0028_002dv_0029_002e-6"><span>version option (-v).<a class="copiable-link" href="#version-option-_0028_002dv_0029_002e-6"> &para;</a></span></h4>
<a class="anchor" id="psktool-version"></a>
<p>This is the &ldquo;output version information and exit&rdquo; option.
This option takes a ArgumentType.KEYWORD argument.
Output version of program and exit.  The default mode is &lsquo;v&rsquo;, a simple
version.  The &lsquo;c&rsquo; mode will print copyright information and &lsquo;n&rsquo; will
print the full copyright notice.
</p><h4 class="subsubheading" id="help-option-_0028_002dh_0029_002e-6"><span>help option (-h).<a class="copiable-link" href="#help-option-_0028_002dh_0029_002e-6"> &para;</a></span></h4>
<a class="anchor" id="psktool-help"></a>
<p>This is the &ldquo;display extended usage information and exit&rdquo; option.
Display usage information and exit.
</p><h4 class="subsubheading" id="more_002dhelp-option-_0028_002d_0021_0029_002e-6"><span>more-help option (-!).<a class="copiable-link" href="#more_002dhelp-option-_0028_002d_0021_0029_002e-6"> &para;</a></span></h4>
<a class="anchor" id="psktool-more_002dhelp"></a>
<p>This is the &ldquo;extended usage information passed thru pager&rdquo; option.
Pass the extended usage information through a pager.
<a class="anchor" id="psktool-exit-status"></a></p><h4 class="subsubheading" id="psktool-exit-status-1"><span>psktool exit status<a class="copiable-link" href="#psktool-exit-status-1"> &para;</a></span></h4>

<p>One of the following exit values will be returned:
</p><dl class="table">
<dt>&lsquo;<samp class="samp">0 (EXIT_SUCCESS)</samp>&rsquo;</dt>
<dd><p>Successful program execution.
</p></dd>
<dt>&lsquo;<samp class="samp">1 (EXIT_FAILURE)</samp>&rsquo;</dt>
<dd><p>The operation failed or the command syntax was not valid.
</p></dd>
</dl>
<a class="anchor" id="psktool-See-Also"></a><h4 class="subsubheading" id="psktool-See-Also-1"><span>psktool See Also<a class="copiable-link" href="#psktool-See-Also-1"> &para;</a></span></h4>
<p>gnutls-cli-debug (1), gnutls-serv (1), srptool (1), certtool (1)
<a class="anchor" id="psktool-Examples"></a></p><h4 class="subsubheading" id="psktool-Examples-1"><span>psktool Examples<a class="copiable-link" href="#psktool-Examples-1"> &para;</a></span></h4>
<p>To add a user &rsquo;psk_identity&rsquo; in <samp class="file">keys.psk</samp> for use with GnuTLS run:
</p><div class="example">
<pre class="example-preformatted">$ ./psktool -u psk_identity -p keys.psk
Generating a random key for user 'psk_identity'
Key stored to keys.psk
$ cat keys.psk
psk_identity:88f3824b3e5659f52d00e959bacab954b6540344
$
</pre></div>

<p>This command will create <samp class="file">keys.psk</samp> if it does not exist
and will add user &rsquo;psk_identity&rsquo;.
</p>

<hr>
</div>
</div>
<div class="subsection-level-extent" id="SRP-authentication">
<div class="nav-panel">
<p>
Next: <a href="#Anonymous-authentication" accesskey="n" rel="next">Anonymous authentication</a>, Previous: <a href="#PSK-authentication" accesskey="p" rel="prev">PSK authentication</a>, Up: <a href="#Shared_002dkey-and-anonymous-authentication" accesskey="u" rel="up">Shared-key and anonymous authentication</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="SRP-authentication-1"><span>4.3.2 SRP authentication<a class="copiable-link" href="#SRP-authentication-1"> &para;</a></span></h4>


<ul class="mini-toc">
<li><a href="#Authentication-using-SRP" accesskey="1">Authentication using <abbr class="acronym">SRP</abbr></a></li>
<li><a href="#srptool-Invocation" accesskey="2">Invoking srptool</a></li>
</ul>
<hr>
<div class="subsubsection-level-extent" id="Authentication-using-SRP">
<div class="nav-panel">
<p>
Next: <a href="#srptool-Invocation" accesskey="n" rel="next">Invoking srptool</a>, Up: <a href="#SRP-authentication" accesskey="u" rel="up">SRP authentication</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsubsection" id="Authentication-using-SRP-1"><span>4.3.2.1 Authentication using <abbr class="acronym">SRP</abbr><a class="copiable-link" href="#Authentication-using-SRP-1"> &para;</a></span></h4>
<a class="index-entry-id" id="index-SRP-authentication"></a>

<p><abbr class="acronym">GnuTLS</abbr> supports authentication via the Secure Remote Password 
or <abbr class="acronym">SRP</abbr> protocol (see [<a class="ref" href="#RFC2945">TOMSRP</a>] for a description).
The <abbr class="acronym">SRP</abbr> key exchange is an extension to the
<abbr class="acronym">TLS</abbr> protocol, and it provides an authenticated with a 
password key exchange. The peers can be identified using a single password, 
or there can be combinations where the client is authenticated using <abbr class="acronym">SRP</abbr>
and the server using a certificate. It is only available under TLS 1.2 or earlier
versions.
</p>
<p>The advantage of <abbr class="acronym">SRP</abbr> authentication, over other proposed
secure password authentication schemes, is that <abbr class="acronym">SRP</abbr> is not
susceptible to off-line dictionary attacks.
Moreover, SRP does not require the server to hold the user&rsquo;s password.
This kind of protection is similar to the one used traditionally in the <abbr class="acronym">UNIX</abbr>
<samp class="file">/etc/passwd</samp> file, where the contents of this file did not cause
harm to the system security if they were revealed.  The <abbr class="acronym">SRP</abbr>
needs instead of the plain password something called a verifier, which
is calculated using the user&rsquo;s password, and if stolen cannot be used
to impersonate the user. 
</p>
<p>Typical conventions in SRP are a password file, called <samp class="file">tpasswd</samp> that 
holds the SRP verifiers (encoded passwords) and another file, <samp class="file">tpasswd.conf</samp>,
which holds the allowed SRP parameters.  The included in GnuTLS helper 
follow those conventions. The srptool program, discussed in the next section
is a tool to manipulate the SRP parameters.
</p>
<p>The implementation in <abbr class="acronym">GnuTLS</abbr> is based on [<a class="ref" href="#TLSSRP">TLSSRP</a>]. The
supported key exchange methods are shown below. Enabling any of these
key exchange methods in a session disables support for TLS1.3.
</p>
<dl class="table">
<dt><code class="code">SRP:</code></dt>
<dd><p>Authentication using the <abbr class="acronym">SRP</abbr> protocol.
</p>
</dd>
<dt><code class="code">SRP_DSS:</code></dt>
<dd><p>Client authentication using the <abbr class="acronym">SRP</abbr> protocol. Server is
authenticated using a certificate with DSA parameters.
</p>
</dd>
<dt><code class="code">SRP_RSA:</code></dt>
<dd><p>Client authentication using the <abbr class="acronym">SRP</abbr> protocol. Server is
authenticated using a certificate with RSA parameters.
</p>
</dd>
</dl>






<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsrp_005fverifier"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_srp_verifier</strong> <code class="def-code-arguments">(const char * <var class="var">username</var>, const char * <var class="var">password</var>, const gnutls_datum_t * <var class="var">salt</var>, const gnutls_datum_t * <var class="var">generator</var>, const gnutls_datum_t * <var class="var">prime</var>, gnutls_datum_t * <var class="var">res</var>)</code><a class="copiable-link" href="#index-gnutls_005fsrp_005fverifier"> &para;</a></span></dt>
<dd><p><var class="var">username</var>: is the user&rsquo;s name
</p>
<p><var class="var">password</var>: is the user&rsquo;s password
</p>
<p><var class="var">salt</var>: should be some randomly generated bytes
</p>
<p><var class="var">generator</var>: is the generator of the group
</p>
<p><var class="var">prime</var>: is the group&rsquo;s prime
</p>
<p><var class="var">res</var>: where the verifier will be stored.
</p>
<p>This function will create an SRP verifier, as specified in
RFC2945.  The  <code class="code">prime</code> and  <code class="code">generator</code> should be one of the static
parameters defined in gnutls/gnutls.h or may be generated.
</p>
<p>The verifier will be allocated with  <code class="code">gnutls_malloc</code> () and will be stored in
 <code class="code">res</code> using binary format.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, or an
error code.
</p></dd></dl>

<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fsrp_005fbase64_005fencode2">gnutls_srp_base64_encode2</a> (const gnutls_datum_t * <var class="var">data</var>, gnutls_datum_t * <var class="var">result</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fsrp_005fbase64_005fdecode2">gnutls_srp_base64_decode2</a> (const gnutls_datum_t * <var class="var">b64_data</var>, gnutls_datum_t * <var class="var">result</var>)</code></dt>
</dl>

<hr>
</div>
<div class="subsubsection-level-extent" id="srptool-Invocation">
<div class="nav-panel">
<p>
Previous: <a href="#Authentication-using-SRP" accesskey="p" rel="prev">Authentication using <abbr class="acronym">SRP</abbr></a>, Up: <a href="#SRP-authentication" accesskey="u" rel="up">SRP authentication</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsubsection" id="Invoking-srptool"><span>4.3.2.2 Invoking srptool<a class="copiable-link" href="#Invoking-srptool"> &para;</a></span></h4>
<a class="index-entry-id" id="index-srptool"></a>

<p>Simple program that emulates the programs in the Stanford SRP (Secure
Remote Password) libraries using GnuTLS.  It is intended for use in  places
where you don&rsquo;t expect SRP authentication to be the used for system users.
</p>
<p>In  brief,  to use SRP you need to create two files. These are the password
file that holds the users and the verifiers associated with  them  and  the
configuration file to hold the group parameters (called tpasswd.conf).
</p>
<a class="anchor" id="srptool-usage"></a><h4 class="subsubheading" id="srptool-help_002fusage-_0028_002d_003f_0029"><span>srptool help/usage (<samp class="option">-?</samp>)<a class="copiable-link" href="#srptool-help_002fusage-_0028_002d_003f_0029"> &para;</a></span></h4>
<a class="index-entry-id" id="index-srptool-help"></a>

<p>The text printed is the same whether selected with the <code class="code">help</code> option
(<samp class="option">--help</samp>) or the <code class="code">more-help</code> option (<samp class="option">--more-help</samp>).  <code class="code">more-help</code> will print
the usage text by passing it through a pager program.
<code class="code">more-help</code> is disabled on platforms without a working
<code class="code">fork(2)</code> function.  The <code class="code">PAGER</code> environment variable is
used to select the program, defaulting to <samp class="file">more</samp>.  Both will exit
with a status code of 0.
</p>
<div class="example">
<pre class="example-preformatted">srptool - GnuTLS SRP tool
Usage:  srptool [ -&lt;flag&gt; [&lt;val&gt;] | --&lt;name&gt;[{=| }&lt;val&gt;] ]... 

None:

   -d, --debug=num            Enable debugging
				- it must be in the range:
				  0 to 9999
   -i, --index=num            specify the index of the group parameters in tpasswd.conf to use
   -u, --username=str         specify a username
   -p, --passwd=str           specify a password file
   -s, --salt=num             specify salt size
       --verify               just verify the password
   -v, --passwd-conf=str      specify a password conf file
       --create-conf=str      Generate a password configuration file

Version, usage and configuration options:

   -v, --version[=arg]        output version information and exit
   -h, --help                 display extended usage information and exit
   -!, --more-help            extended usage information passed thru pager

Options are specified by doubled hyphens and their name or by a single
hyphen and the flag character.

Simple program that emulates the programs in the Stanford SRP (Secure
Remote Password) libraries using GnuTLS.  It is intended for use in  places
where you don't expect SRP authentication to be the used for system users.

In  brief,  to use SRP you need to create two files. These are the password
file that holds the users and the verifiers associated with  them  and  the
configuration file to hold the group parameters (called tpasswd.conf).

Please send bug reports to:  &lt;bugs@gnutls.org&gt;

</pre></div>

<h4 class="subsubheading" id="debug-option-_0028_002dd_0029_002e-7"><span>debug option (-d).<a class="copiable-link" href="#debug-option-_0028_002dd_0029_002e-7"> &para;</a></span></h4>
<a class="anchor" id="srptool-debug"></a>
<p>This is the &ldquo;enable debugging&rdquo; option.
This option takes a ArgumentType.NUMBER argument.
Specifies the debug level.
</p><h4 class="subsubheading" id="verify-option_002e-1"><span>verify option.<a class="copiable-link" href="#verify-option_002e-1"> &para;</a></span></h4>
<a class="anchor" id="srptool-verify"></a>
<p>This is the &ldquo;just verify the password&rdquo; option.
Verifies the password provided against the password file.
</p><h4 class="subsubheading" id="passwd_002dconf-option-_0028_002dv_0029_002e"><span>passwd-conf option (-v).<a class="copiable-link" href="#passwd_002dconf-option-_0028_002dv_0029_002e"> &para;</a></span></h4>
<a class="anchor" id="srptool-passwd_002dconf"></a>
<p>This is the &ldquo;specify a password conf file&rdquo; option.
This option takes a ArgumentType.STRING argument.
Specify a filename or a PKCS #11 URL to read the CAs from.
</p><h4 class="subsubheading" id="create_002dconf-option_002e"><span>create-conf option.<a class="copiable-link" href="#create_002dconf-option_002e"> &para;</a></span></h4>
<a class="anchor" id="srptool-create_002dconf"></a>
<p>This is the &ldquo;generate a password configuration file&rdquo; option.
This option takes a ArgumentType.STRING argument.
This generates a password configuration file (tpasswd.conf)
containing the required for TLS parameters.
</p><h4 class="subsubheading" id="version-option-_0028_002dv_0029_002e-7"><span>version option (-v).<a class="copiable-link" href="#version-option-_0028_002dv_0029_002e-7"> &para;</a></span></h4>
<a class="anchor" id="srptool-version"></a>
<p>This is the &ldquo;output version information and exit&rdquo; option.
This option takes a ArgumentType.KEYWORD argument.
Output version of program and exit.  The default mode is &lsquo;v&rsquo;, a simple
version.  The &lsquo;c&rsquo; mode will print copyright information and &lsquo;n&rsquo; will
print the full copyright notice.
</p><h4 class="subsubheading" id="help-option-_0028_002dh_0029_002e-7"><span>help option (-h).<a class="copiable-link" href="#help-option-_0028_002dh_0029_002e-7"> &para;</a></span></h4>
<a class="anchor" id="srptool-help"></a>
<p>This is the &ldquo;display extended usage information and exit&rdquo; option.
Display usage information and exit.
</p><h4 class="subsubheading" id="more_002dhelp-option-_0028_002d_0021_0029_002e-7"><span>more-help option (-!).<a class="copiable-link" href="#more_002dhelp-option-_0028_002d_0021_0029_002e-7"> &para;</a></span></h4>
<a class="anchor" id="srptool-more_002dhelp"></a>
<p>This is the &ldquo;extended usage information passed thru pager&rdquo; option.
Pass the extended usage information through a pager.
<a class="anchor" id="srptool-exit-status"></a></p><h4 class="subsubheading" id="srptool-exit-status-1"><span>srptool exit status<a class="copiable-link" href="#srptool-exit-status-1"> &para;</a></span></h4>

<p>One of the following exit values will be returned:
</p><dl class="table">
<dt>&lsquo;<samp class="samp">0 (EXIT_SUCCESS)</samp>&rsquo;</dt>
<dd><p>Successful program execution.
</p></dd>
<dt>&lsquo;<samp class="samp">1 (EXIT_FAILURE)</samp>&rsquo;</dt>
<dd><p>The operation failed or the command syntax was not valid.
</p></dd>
</dl>
<a class="anchor" id="srptool-See-Also"></a><h4 class="subsubheading" id="srptool-See-Also-1"><span>srptool See Also<a class="copiable-link" href="#srptool-See-Also-1"> &para;</a></span></h4>
<p>gnutls-cli-debug (1), gnutls-serv (1), srptool (1), psktool (1), certtool (1)
<a class="anchor" id="srptool-Examples"></a></p><h4 class="subsubheading" id="srptool-Examples-1"><span>srptool Examples<a class="copiable-link" href="#srptool-Examples-1"> &para;</a></span></h4>
<p>To create <samp class="file">tpasswd.conf</samp> which holds the g and n values for SRP protocol
(generator and a large prime), run:
</p><div class="example">
<pre class="example-preformatted">$ srptool --create-conf /etc/tpasswd.conf
</pre></div>

<p>This command will create <samp class="file">/etc/tpasswd</samp> and will add user &rsquo;test&rsquo; (you
will also be prompted for a password). Verifiers are stored by default
in the way libsrp expects.
</p><div class="example">
<pre class="example-preformatted">$ srptool --passwd /etc/tpasswd --passwd-conf /etc/tpasswd.conf -u test
</pre></div>


<p>This command will check against a password. If the password matches
the one in <samp class="file">/etc/tpasswd</samp> you will get an ok.
</p><div class="example">
<pre class="example-preformatted">$ srptool --passwd /etc/tpasswd --passwd\-conf /etc/tpasswd.conf --verify -u test
</pre></div>

<hr>
</div>
</div>
<div class="subsection-level-extent" id="Anonymous-authentication">
<div class="nav-panel">
<p>
Previous: <a href="#SRP-authentication" accesskey="p" rel="prev">SRP authentication</a>, Up: <a href="#Shared_002dkey-and-anonymous-authentication" accesskey="u" rel="up">Shared-key and anonymous authentication</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Anonymous-authentication-1"><span>4.3.3 Anonymous authentication<a class="copiable-link" href="#Anonymous-authentication-1"> &para;</a></span></h4>
<a class="index-entry-id" id="index-anonymous-authentication"></a>

<p>The anonymous key exchange offers encryption without any
indication of the peer&rsquo;s identity.  This kind of authentication
is vulnerable to a man in the middle attack, but can be
used even if there is no prior communication or shared trusted parties 
with the peer. It is useful to establish a session over which certificate
authentication will occur in order to hide the identities of the participants
from passive eavesdroppers. It is only available under TLS 1.2 or earlier
versions.
</p>
<p>Unless in the above case, it is not recommended to use anonymous authentication. 
In the cases where there is no prior communication with the peers, 
an alternative with better properties, such as key continuity, is trust on first use
(see <a class="ref" href="#Verifying-a-certificate-using-trust-on-first-use-authentication">Verifying a certificate using trust on first use authentication</a>).
</p>
<p>The available key exchange algorithms for anonymous authentication are
shown below, but note that few public servers support them, and they 
have to be explicitly enabled. These ciphersuites are negotiated only under
TLS 1.2.
</p>
<dl class="table">
<dt><code class="code">ANON_DH:</code></dt>
<dd><p>This algorithm exchanges Diffie-Hellman parameters.
</p>
</dd>
<dt><code class="code">ANON_ECDH:</code></dt>
<dd><p>This algorithm exchanges elliptic curve Diffie-Hellman parameters. It is more 
efficient than ANON_DH on equivalent security levels.
</p>
</dd>
</dl>

<hr>
</div>
</div>
<div class="section-level-extent" id="Selecting-an-appropriate-authentication-method">
<div class="nav-panel">
<p>
Previous: <a href="#Shared_002dkey-and-anonymous-authentication" accesskey="p" rel="prev">Shared-key and anonymous authentication</a>, Up: <a href="#Authentication-methods" accesskey="u" rel="up">Authentication methods</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Selecting-an-appropriate-authentication-method-1"><span>4.4 Selecting an appropriate authentication method<a class="copiable-link" href="#Selecting-an-appropriate-authentication-method-1"> &para;</a></span></h3>

<p>This section provides some guidance on how to use the available authentication
methods in <abbr class="acronym">GnuTLS</abbr> in various scenarios.
</p>
<ul class="mini-toc">
<li><a href="#Two-peers-with-an-out_002dof_002dband-channel" accesskey="1">Two peers with an out-of-band channel</a></li>
<li><a href="#Two-peers-without-an-out_002dof_002dband-channel" accesskey="2">Two peers without an out-of-band channel</a></li>
<li><a href="#Two-peers-and-a-trusted-third-party" accesskey="3">Two peers and a trusted third party</a></li>
</ul>
<div class="subsection-level-extent" id="Two-peers-with-an-out_002dof_002dband-channel">
<h4 class="subsection"><span>4.4.1 Two peers with an out-of-band channel<a class="copiable-link" href="#Two-peers-with-an-out_002dof_002dband-channel"> &para;</a></span></h4>

<p>Let&rsquo;s consider two peers who need to communicate over an untrusted channel
(the Internet), but have an out-of-band channel available. The latter
channel is considered safe from eavesdropping and message modification and thus
can be used for an initial bootstrapping of the protocol. The options 
available are:
</p><ul class="itemize mark-bullet">
<li>Pre-shared keys (see <a class="ref" href="#PSK-authentication">PSK authentication</a>). The server and a
client communicate a shared randomly generated key over the trusted
channel and use it to negotiate further sessions over the untrusted channel.

</li><li>Passwords (see <a class="ref" href="#SRP-authentication">SRP authentication</a>). The client communicates
to the server its username and password of choice and uses it to
negotiate further sessions over the untrusted channel.

</li><li>Public keys (see <a class="ref" href="#Certificate-authentication">Certificate authentication</a>). The client 
and the server exchange their public keys (or fingerprints of them)
over the trusted channel. 
On future sessions over the untrusted channel they verify the key
being the same (similar to <a class="ref" href="#Verifying-a-certificate-using-trust-on-first-use-authentication">Verifying a certificate using trust on first use authentication</a>).
</li></ul>

<p>Provided that the out-of-band channel is trusted all of the above provide
a similar level of protection. An out-of-band channel may be the initial
bootstrapping of a user&rsquo;s PC in a corporate environment, in-person
communication, communication over an alternative network (e.g. the phone
network), etc.
</p>
</div>
<div class="subsection-level-extent" id="Two-peers-without-an-out_002dof_002dband-channel">
<h4 class="subsection"><span>4.4.2 Two peers without an out-of-band channel<a class="copiable-link" href="#Two-peers-without-an-out_002dof_002dband-channel"> &para;</a></span></h4>

<p>When an out-of-band channel is not available a peer cannot be reliably
authenticated. What can be done, however, is to allow some form of
registration of users connecting for the first time and ensure that their
keys remain the same after that initial connection. This is termed
key continuity or trust on first use (TOFU).
</p>
<p>The available option is to use public key authentication (see <a class="ref" href="#Certificate-authentication">Certificate authentication</a>). 
The client and the server store each other&rsquo;s public keys (or fingerprints of them)
and associate them with their identity.
On future sessions over the untrusted channel they verify the keys
being the same (see <a class="ref" href="#Verifying-a-certificate-using-trust-on-first-use-authentication">Verifying a certificate using trust on first use authentication</a>).
</p>
<p>To mitigate the uncertainty of the information exchanged in the first 
connection other channels over the Internet may be used, e.g., <abbr class="acronym">DNSSEC</abbr>
(see <a class="ref" href="#Verifying-a-certificate-using-DANE">Verifying a certificate using DANE (DNSSEC)</a>).
</p>
</div>
<div class="subsection-level-extent" id="Two-peers-and-a-trusted-third-party">
<h4 class="subsection"><span>4.4.3 Two peers and a trusted third party<a class="copiable-link" href="#Two-peers-and-a-trusted-third-party"> &para;</a></span></h4>

<p>When a trusted third party is available (or a certificate authority) 
the most suitable option is to use 
certificate authentication (see <a class="ref" href="#Certificate-authentication">Certificate authentication</a>). 
The client and the server obtain certificates that associate their identity
and public keys using a digital signature by the trusted party and use 
them to on the subsequent communications with each other. 
Each party verifies the peer&rsquo;s certificate using the trusted third party&rsquo;s 
signature. The parameters of the third party&rsquo;s signature are present
in its certificate which must be available to all communicating parties.
</p>
<p>While the above is the typical authentication method for servers in the
Internet by using the commercial CAs, the users that act as clients in the
protocol rarely possess such certificates. In that case a hybrid method
can be used where the server is authenticated by the client using the
commercial CAs and the client is authenticated based on some information
the client provided over the initial server-authenticated channel. The
available options are:
</p><ul class="itemize mark-bullet">
<li>Passwords (see <a class="ref" href="#SRP-authentication">SRP authentication</a>). The client communicates
to the server its username and password of choice on the initial
server-authenticated connection and uses it to negotiate further sessions. 
This is possible because the SRP protocol allows for the server to be 
authenticated using a certificate and the client using the
password.

</li><li>Public keys (see <a class="ref" href="#Certificate-authentication">Certificate authentication</a>). The client 
sends its public key to the server (or a fingerprint of it) over the
initial server-authenticated connection. 
On future sessions the client verifies the server using the third party
certificate and the server verifies that the client&rsquo;s public key remained 
the same (see <a class="ref" href="#Verifying-a-certificate-using-trust-on-first-use-authentication">Verifying a certificate using trust on first use authentication</a>).
</li></ul>


<hr>
</div>
</div>
</div>
<div class="chapter-level-extent" id="Hardware-security-modules-and-abstract-key-types">
<div class="nav-panel">
<p>
Next: <a href="#How-to-use-GnuTLS-in-applications" accesskey="n" rel="next">How to use <abbr class="acronym">GnuTLS</abbr> in applications</a>, Previous: <a href="#Authentication-methods" accesskey="p" rel="prev">Authentication methods</a>, Up: <a href="#Top" accesskey="u" rel="up">GnuTLS</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h2 class="chapter" id="Abstract-key-types-and-Hardware-security-modules"><span>5 Abstract key types and Hardware security modules<a class="copiable-link" href="#Abstract-key-types-and-Hardware-security-modules"> &para;</a></span></h2>

<p>In several cases storing the long term cryptographic keys in a hard disk or
even in memory poses a significant risk. Once the system they are stored
is compromised the keys must be replaced as the secrecy of future sessions
is no longer guaranteed. Moreover, past sessions that were not protected by a
perfect forward secrecy offering ciphersuite are also to be assumed compromised.
</p>
<p>If such threats need to be addressed, then it may be wise storing the keys in a security
module such as a smart card, an HSM or the TPM chip. Those modules ensure the
protection of the cryptographic keys by only allowing operations on them and
preventing their extraction. The purpose of the abstract key API is to provide
an API that will allow the handle of keys in memory and files, as well as keys
stored in such modules.
</p>
<p>In GnuTLS the approach is to handle all keys transparently by the high level API, e.g.,
the API that loads a key or certificate from a file.
The high-level API will accept URIs in addition to files that specify keys on an HSM or in TPM,
and a callback function will be used to obtain any required keys. The URI format is defined in
[<a class="ref" href="#PKCS11URI">PKCS11URI</a>].
</p>
<p>More information on the API is provided in the next sections. Examples of a URI of a certificate 
stored in an HSM, as well as a key stored in the TPM chip are shown below. To discover the URIs 
of the objects the <code class="code">p11tool</code> (see <a class="ref" href="#p11tool-Invocation">Invoking p11tool</a>).
</p><div class="example">
<pre class="example-preformatted">pkcs11:token=Nikos;serial=307521161601031;model=PKCS%2315; \
manufacturer=EnterSafe;object=test1;type=cert

</pre></div>



<ul class="mini-toc">
<li><a href="#Abstract-key-types" accesskey="1">Abstract key types</a></li>
<li><a href="#Application_002dspecific-keys" accesskey="2">System and application-specific keys</a></li>
<li><a href="#Smart-cards-and-HSMs" accesskey="3">Smart cards and HSMs</a></li>
<li><a href="#Trusted-Platform-Module" accesskey="4">Trusted Platform Module (TPM)</a></li>
</ul>
<hr>
<div class="section-level-extent" id="Abstract-key-types">
<div class="nav-panel">
<p>
Next: <a href="#Application_002dspecific-keys" accesskey="n" rel="next">System and application-specific keys</a>, Up: <a href="#Hardware-security-modules-and-abstract-key-types" accesskey="u" rel="up">Abstract key types and Hardware security modules</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Abstract-key-types-1"><span>5.1 Abstract key types<a class="copiable-link" href="#Abstract-key-types-1"> &para;</a></span></h3>
<a class="index-entry-id" id="index-abstract-types"></a>

<p>Since there are many forms of a public or private keys supported by <abbr class="acronym">GnuTLS</abbr> such as
<abbr class="acronym">X.509</abbr>, <abbr class="acronym">PKCS</abbr> #11 or TPM it is desirable to allow common operations
on them. For these reasons the abstract <code class="code">gnutls_privkey_t</code> and <code class="code">gnutls_pubkey_t</code> were
introduced in <code class="code">gnutls/abstract.h</code> header. Those types are initialized using a specific type of 
key and then can be used to perform operations in an abstract way. For example in order
to sign an X.509 certificate with a key that resides in a token the following steps can be
used.
</p>
<div class="example">
<pre class="example-preformatted">#include &lt;gnutls/abstract.h&gt;

void sign_cert( gnutls_x509_crt_t to_be_signed)
{
gnutls_x509_crt_t ca_cert;
gnutls_privkey_t abs_key;

  /* initialize the abstract key */
  gnutls_privkey_init(&amp;abs_key);

  /* keys stored in tokens are identified by URLs */
  gnutls_privkey_import_url(abs_key, key_url);

  gnutls_x509_crt_init(&amp;ca_cert);
  gnutls_x509_crt_import_url(&amp;ca_cert, cert_url);

  /* sign the certificate to be signed */
  gnutls_x509_crt_privkey_sign(to_be_signed, ca_cert, abs_key, 
                               GNUTLS_DIG_SHA256, 0);
}
</pre></div>


<ul class="mini-toc">
<li><a href="#Abstract-public-keys" accesskey="1">Public keys</a></li>
<li><a href="#Abstract-private-keys" accesskey="2">Private keys</a></li>
<li><a href="#Operations" accesskey="3">Operations</a></li>
</ul>
<hr>
<div class="subsection-level-extent" id="Abstract-public-keys">
<div class="nav-panel">
<p>
Next: <a href="#Abstract-private-keys" accesskey="n" rel="next">Private keys</a>, Up: <a href="#Abstract-key-types" accesskey="u" rel="up">Abstract key types</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Public-keys"><span>5.1.1 Public keys<a class="copiable-link" href="#Public-keys"> &para;</a></span></h4>
<p>An abstract <code class="code">gnutls_pubkey_t</code> can be initialized and freed by
using the functions below.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpubkey_005finit">gnutls_pubkey_init</a> (gnutls_pubkey_t * <var class="var">key</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fpubkey_005fdeinit">gnutls_pubkey_deinit</a> (gnutls_pubkey_t <var class="var">key</var>)</code></dt>
</dl>

<p>After initialization its values can be imported from
an existing structure like <code class="code">gnutls_x509_crt_t</code>,
or through an ASN.1 encoding of the X.509 <code class="code">SubjectPublicKeyInfo</code>
sequence.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpubkey_005fimport_005fx509">gnutls_pubkey_import_x509</a> (gnutls_pubkey_t <var class="var">key</var>, gnutls_x509_crt_t <var class="var">crt</var>, unsigned int <var class="var">flags</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpubkey_005fimport_005fpkcs11">gnutls_pubkey_import_pkcs11</a> (gnutls_pubkey_t <var class="var">key</var>, gnutls_pkcs11_obj_t <var class="var">obj</var>, unsigned int <var class="var">flags</var>)</code></dt>
</dl>

<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpubkey_005fimport_005furl">gnutls_pubkey_import_url</a> (gnutls_pubkey_t <var class="var">key</var>, const char * <var class="var">url</var>, unsigned int <var class="var">flags</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpubkey_005fimport_005fprivkey">gnutls_pubkey_import_privkey</a> (gnutls_pubkey_t <var class="var">key</var>, gnutls_privkey_t <var class="var">pkey</var>, unsigned int <var class="var">usage</var>, unsigned int <var class="var">flags</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpubkey_005fimport">gnutls_pubkey_import</a> (gnutls_pubkey_t <var class="var">key</var>, const gnutls_datum_t * <var class="var">data</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpubkey_005fexport">gnutls_pubkey_export</a> (gnutls_pubkey_t <var class="var">key</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, void * <var class="var">output_data</var>, size_t * <var class="var">output_data_size</var>)</code></dt>
</dl>





<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fexport2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_export2</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">key</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, gnutls_datum_t * <var class="var">out</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fexport2"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: Holds the certificate
</p>
<p><var class="var">format</var>: the format of output params. One of PEM or DER.
</p>
<p><var class="var">out</var>: will contain a certificate PEM or DER encoded
</p>
<p>This function will export the public key to DER or PEM format.
The contents of the exported data is the SubjectPublicKeyInfo
X.509 structure.
</p>
<p>The output buffer will be allocated using <code class="code">gnutls_malloc()</code> .
</p>
<p>If the structure is PEM encoded, it will have a header
of &quot;BEGIN CERTIFICATE&quot;.
</p>
<p><strong class="strong">Returns:</strong> In case of failure a negative error code will be
returned, and 0 on success.
</p>
<p><strong class="strong">Since:</strong> 3.1.3
</p></dd></dl>

<p>Other helper functions that allow directly importing from raw X.509 structures are shown below.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpubkey_005fimport_005fx509_005fraw">gnutls_pubkey_import_x509_raw</a> (gnutls_pubkey_t <var class="var">pkey</var>, const gnutls_datum_t * <var class="var">data</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, unsigned int <var class="var">flags</var>)</code></dt>
</dl>

<p>An important function is <a class="ref" href="#gnutls_005fpubkey_005fimport_005furl">gnutls_pubkey_import_url</a> which will import
public keys from URLs that identify objects stored in tokens (see <a class="ref" href="#Smart-cards-and-HSMs">Smart cards and HSMs</a> and <a class="ref" href="#Trusted-Platform-Module">Trusted Platform Module (TPM)</a>).
A function to check for a supported by GnuTLS URL is <a class="ref" href="#gnutls_005furl_005fis_005fsupported">gnutls_url_is_supported</a>.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005furl_005fis_005fsupported"><span class="category-def">Function: </span><span><code class="def-type">unsigned</code> <strong class="def-name">gnutls_url_is_supported</strong> <code class="def-code-arguments">(const char * <var class="var">url</var>)</code><a class="copiable-link" href="#index-gnutls_005furl_005fis_005fsupported"> &para;</a></span></dt>
<dd><p><var class="var">url</var>: A URI to be tested
</p>
<p>Check whether the provided  <code class="code">url</code> is supported.  Depending on the system libraries
GnuTLS may support pkcs11, tpmkey or other URLs.
</p>
<p><strong class="strong">Returns:</strong> return non-zero if the given URL is supported, and zero if
it is not known.
</p>
<p><strong class="strong">Since:</strong> 3.1.0
</p></dd></dl>

<p>Additional functions are available that will return
information over a public key, such as a unique key ID, as well as a function 
that given a public key fingerprint would provide a memorable sketch.
</p>
<p>Note that <a class="ref" href="#gnutls_005fpubkey_005fget_005fkey_005fid">gnutls_pubkey_get_key_id</a> calculates a SHA1 digest of the 
public key as a DER-formatted, subjectPublicKeyInfo object.  Other implementations 
use different approaches, e.g., some use the &ldquo;common method&rdquo; described in
section 4.2.1.2 of [<a class="ref" href="#RFC5280">RFC5280</a>] which calculates a digest on a part of the
subjectPublicKeyInfo object.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpubkey_005fget_005fpk_005falgorithm">gnutls_pubkey_get_pk_algorithm</a> (gnutls_pubkey_t <var class="var">key</var>, unsigned int * <var class="var">bits</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpubkey_005fget_005fpreferred_005fhash_005falgorithm">gnutls_pubkey_get_preferred_hash_algorithm</a> (gnutls_pubkey_t <var class="var">key</var>, gnutls_digest_algorithm_t * <var class="var">hash</var>, unsigned int * <var class="var">mand</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpubkey_005fget_005fkey_005fid">gnutls_pubkey_get_key_id</a> (gnutls_pubkey_t <var class="var">key</var>, unsigned int <var class="var">flags</var>, unsigned char * <var class="var">output_data</var>, size_t * <var class="var">output_data_size</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005frandom_005fart">gnutls_random_art</a> (gnutls_random_art_t <var class="var">type</var>, const char * <var class="var">key_type</var>, unsigned int <var class="var">key_size</var>, void * <var class="var">fpr</var>, size_t <var class="var">fpr_size</var>, gnutls_datum_t * <var class="var">art</var>)</code></dt>
</dl>

<p>To export the key-specific parameters, or obtain a unique key ID the following functions are provided.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpubkey_005fexport_005frsa_005fraw2">gnutls_pubkey_export_rsa_raw2</a> (gnutls_pubkey_t <var class="var">key</var>, gnutls_datum_t * <var class="var">m</var>, gnutls_datum_t * <var class="var">e</var>, unsigned <var class="var">flags</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpubkey_005fexport_005fdsa_005fraw2">gnutls_pubkey_export_dsa_raw2</a> (gnutls_pubkey_t <var class="var">key</var>, gnutls_datum_t * <var class="var">p</var>, gnutls_datum_t * <var class="var">q</var>, gnutls_datum_t * <var class="var">g</var>, gnutls_datum_t * <var class="var">y</var>, unsigned <var class="var">flags</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpubkey_005fexport_005fecc_005fraw2">gnutls_pubkey_export_ecc_raw2</a> (gnutls_pubkey_t <var class="var">key</var>, gnutls_ecc_curve_t * <var class="var">curve</var>, gnutls_datum_t * <var class="var">x</var>, gnutls_datum_t * <var class="var">y</var>, unsigned int <var class="var">flags</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpubkey_005fexport_005fecc_005fx962">gnutls_pubkey_export_ecc_x962</a> (gnutls_pubkey_t <var class="var">key</var>, gnutls_datum_t * <var class="var">parameters</var>, gnutls_datum_t * <var class="var">ecpoint</var>)</code></dt>
</dl>

<hr>
</div>
<div class="subsection-level-extent" id="Abstract-private-keys">
<div class="nav-panel">
<p>
Next: <a href="#Operations" accesskey="n" rel="next">Operations</a>, Previous: <a href="#Abstract-public-keys" accesskey="p" rel="prev">Public keys</a>, Up: <a href="#Abstract-key-types" accesskey="u" rel="up">Abstract key types</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Private-keys"><span>5.1.2 Private keys<a class="copiable-link" href="#Private-keys"> &para;</a></span></h4>
<p>An abstract <code class="code">gnutls_privkey_t</code> can be initialized and freed by
using the functions below.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fprivkey_005finit">gnutls_privkey_init</a> (gnutls_privkey_t * <var class="var">key</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fprivkey_005fdeinit">gnutls_privkey_deinit</a> (gnutls_privkey_t <var class="var">key</var>)</code></dt>
</dl>

<p>After initialization its values can be imported from
an existing structure like <code class="code">gnutls_x509_privkey_t</code>,
but unlike public keys it cannot be exported. That is
to allow abstraction over keys stored in hardware that 
makes available only operations.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fprivkey_005fimport_005fx509">gnutls_privkey_import_x509</a> (gnutls_privkey_t <var class="var">pkey</var>, gnutls_x509_privkey_t <var class="var">key</var>, unsigned int <var class="var">flags</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fprivkey_005fimport_005fpkcs11">gnutls_privkey_import_pkcs11</a> (gnutls_privkey_t <var class="var">pkey</var>, gnutls_pkcs11_privkey_t <var class="var">key</var>, unsigned int <var class="var">flags</var>)</code></dt>
</dl>

<p>Other helper functions that allow directly importing from raw X.509
structures are shown below. Again, as with public keys, private keys
can be imported from a hardware module using URLs.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fimport_005furl"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_import_url</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">key</var>, const char * <var class="var">url</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fimport_005furl"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: A key of type <code class="code">gnutls_privkey_t</code> 
</p>
<p><var class="var">url</var>: A PKCS 11 url
</p>
<p><var class="var">flags</var>: should be zero
</p>
<p>This function will import a PKCS11 or TPM URL as a
private key. The supported URL types can be checked
using <code class="code">gnutls_url_is_supported()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.1.0
</p></dd></dl>

<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fprivkey_005fimport_005fx509_005fraw">gnutls_privkey_import_x509_raw</a> (gnutls_privkey_t <var class="var">pkey</var>, const gnutls_datum_t * <var class="var">data</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, const char * <var class="var">password</var>, unsigned int <var class="var">flags</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fprivkey_005fget_005fpk_005falgorithm">gnutls_privkey_get_pk_algorithm</a> (gnutls_privkey_t <var class="var">key</var>, unsigned int * <var class="var">bits</var>)</code></dt>
<dt><code class="code"><var class="var">gnutls_privkey_type_t</var> <a class="ref" href="#gnutls_005fprivkey_005fget_005ftype">gnutls_privkey_get_type</a> (gnutls_privkey_t <var class="var">key</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fprivkey_005fstatus">gnutls_privkey_status</a> (gnutls_privkey_t <var class="var">key</var>)</code></dt>
</dl>

<p>In order to support cryptographic operations using 
an external API, the following function is provided.
This allows for a simple extensibility API without
resorting to <abbr class="acronym">PKCS</abbr> #11.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fimport_005fext4"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_import_ext4</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">pkey</var>, void * <var class="var">userdata</var>, gnutls_privkey_sign_data_func <var class="var">sign_data_fn</var>, gnutls_privkey_sign_hash_func <var class="var">sign_hash_fn</var>, gnutls_privkey_decrypt_func <var class="var">decrypt_fn</var>, gnutls_privkey_deinit_func <var class="var">deinit_fn</var>, gnutls_privkey_info_func <var class="var">info_fn</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fimport_005fext4"> &para;</a></span></dt>
<dd><p><var class="var">pkey</var>: The private key
</p>
<p><var class="var">userdata</var>: private data to be provided to the callbacks
</p>
<p><var class="var">sign_data_fn</var>: callback for signature operations (may be <code class="code">NULL</code> )
</p>
<p><var class="var">sign_hash_fn</var>: callback for signature operations (may be <code class="code">NULL</code> )
</p>
<p><var class="var">decrypt_fn</var>: callback for decryption operations (may be <code class="code">NULL</code> )
</p>
<p><var class="var">deinit_fn</var>: a deinitialization function
</p>
<p><var class="var">info_fn</var>: returns info about the public key algorithm (should not be <code class="code">NULL</code> )
</p>
<p><var class="var">flags</var>: Flags for the import
</p>
<p>This function will associate the given callbacks with the
<code class="code">gnutls_privkey_t</code>  type. At least one of the callbacks
must be non-null. If a deinitialization function is provided
then flags is assumed to contain <code class="code">GNUTLS_PRIVKEY_IMPORT_AUTO_RELEASE</code> .
</p>
<p>Note that in contrast with the signing function of
<code class="code">gnutls_privkey_import_ext3()</code> , the signing functions provided to this
function take explicitly the signature algorithm as parameter and
different functions are provided to sign the data and hashes.
</p>
<p>The  <code class="code">sign_hash_fn</code> is to be called to sign pre-hashed data. The input
to the callback is the output of the hash (such as SHA256) corresponding
to the signature algorithm. For RSA PKCS<code class="code">1</code>  signatures, the signature
algorithm can be set to <code class="code">GNUTLS_SIGN_RSA_RAW</code> , and in that case the data
should be handled as if they were an RSA PKCS<code class="code">1</code>  DigestInfo structure.
</p>
<p>The  <code class="code">sign_data_fn</code> is to be called to sign data. The input data will be
he data to be signed (and hashed), with the provided signature
algorithm. This function is to be used for signature algorithms like
Ed25519 which cannot take pre-hashed data as input.
</p>
<p>When both  <code class="code">sign_data_fn</code> and  <code class="code">sign_hash_fn</code> functions are provided they
must be able to operate on all the supported signature algorithms,
unless prohibited by the type of the algorithm (e.g., as with Ed25519).
</p>
<p>The  <code class="code">info_fn</code> must provide information on the signature algorithms supported by
this private key, and should support the flags <code class="code">GNUTLS_PRIVKEY_INFO_PK_ALGO</code> ,
<code class="code">GNUTLS_PRIVKEY_INFO_HAVE_SIGN_ALGO</code>  and <code class="code">GNUTLS_PRIVKEY_INFO_PK_ALGO_BITS</code> .
It must return -1 on unknown flags.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.6.0
</p></dd></dl>

<p>On the private keys where exporting of parameters is possible (i.e.,
software keys), the following functions are also available.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fprivkey_005fexport_005frsa_005fraw2">gnutls_privkey_export_rsa_raw2</a> (gnutls_privkey_t <var class="var">key</var>, gnutls_datum_t * <var class="var">m</var>, gnutls_datum_t * <var class="var">e</var>, gnutls_datum_t * <var class="var">d</var>, gnutls_datum_t * <var class="var">p</var>, gnutls_datum_t * <var class="var">q</var>, gnutls_datum_t * <var class="var">u</var>, gnutls_datum_t * <var class="var">e1</var>, gnutls_datum_t * <var class="var">e2</var>, unsigned int <var class="var">flags</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fprivkey_005fexport_005fdsa_005fraw2">gnutls_privkey_export_dsa_raw2</a> (gnutls_privkey_t <var class="var">key</var>, gnutls_datum_t * <var class="var">p</var>, gnutls_datum_t * <var class="var">q</var>, gnutls_datum_t * <var class="var">g</var>, gnutls_datum_t * <var class="var">y</var>, gnutls_datum_t * <var class="var">x</var>, unsigned int <var class="var">flags</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fprivkey_005fexport_005fecc_005fraw2">gnutls_privkey_export_ecc_raw2</a> (gnutls_privkey_t <var class="var">key</var>, gnutls_ecc_curve_t * <var class="var">curve</var>, gnutls_datum_t * <var class="var">x</var>, gnutls_datum_t * <var class="var">y</var>, gnutls_datum_t * <var class="var">k</var>, unsigned int <var class="var">flags</var>)</code></dt>
</dl>

<hr>
</div>
<div class="subsection-level-extent" id="Operations">
<div class="nav-panel">
<p>
Previous: <a href="#Abstract-private-keys" accesskey="p" rel="prev">Private keys</a>, Up: <a href="#Abstract-key-types" accesskey="u" rel="up">Abstract key types</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Operations-1"><span>5.1.3 Operations<a class="copiable-link" href="#Operations-1"> &para;</a></span></h4>
<p>The abstract key types can be used to access signing and
signature verification operations with the underlying keys.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fverify_005fdata2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_verify_data2</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">pubkey</var>, gnutls_sign_algorithm_t <var class="var">algo</var>, unsigned int <var class="var">flags</var>, const gnutls_datum_t * <var class="var">data</var>, const gnutls_datum_t * <var class="var">signature</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fverify_005fdata2"> &para;</a></span></dt>
<dd><p><var class="var">pubkey</var>: Holds the public key
</p>
<p><var class="var">algo</var>: The signature algorithm used
</p>
<p><var class="var">flags</var>: Zero or an OR list of <code class="code">gnutls_certificate_verify_flags</code> 
</p>
<p><var class="var">data</var>: holds the signed data
</p>
<p><var class="var">signature</var>: contains the signature
</p>
<p>This function will verify the given signed data, using the
parameters from the certificate.
</p>
<p><strong class="strong">Returns:</strong> In case of a verification failure <code class="code">GNUTLS_E_PK_SIG_VERIFY_FAILED</code>  
is returned, and zero or positive code on success. For known to be insecure
signatures this function will return <code class="code">GNUTLS_E_INSUFFICIENT_SECURITY</code>  unless
the flag <code class="code">GNUTLS_VERIFY_ALLOW_BROKEN</code>  is specified.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fverify_005fhash2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_verify_hash2</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">key</var>, gnutls_sign_algorithm_t <var class="var">algo</var>, unsigned int <var class="var">flags</var>, const gnutls_datum_t * <var class="var">hash</var>, const gnutls_datum_t * <var class="var">signature</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fverify_005fhash2"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: Holds the public key
</p>
<p><var class="var">algo</var>: The signature algorithm used
</p>
<p><var class="var">flags</var>: Zero or an OR list of <code class="code">gnutls_certificate_verify_flags</code> 
</p>
<p><var class="var">hash</var>: holds the hash digest to be verified
</p>
<p><var class="var">signature</var>: contains the signature
</p>
<p>This function will verify the given signed digest, using the
parameters from the public key. Note that unlike <code class="code">gnutls_privkey_sign_hash()</code> ,
this function accepts a signature algorithm instead of a digest algorithm.
You can use <code class="code">gnutls_pk_to_sign()</code>  to get the appropriate value.
</p>
<p><strong class="strong">Returns:</strong> In case of a verification failure <code class="code">GNUTLS_E_PK_SIG_VERIFY_FAILED</code>  
is returned, and zero or positive code on success. For known to be insecure
signatures this function will return <code class="code">GNUTLS_E_INSUFFICIENT_SECURITY</code>  unless
the flag <code class="code">GNUTLS_VERIFY_ALLOW_BROKEN</code>  is specified.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fencrypt_005fdata"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_encrypt_data</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">key</var>, unsigned int <var class="var">flags</var>, const gnutls_datum_t * <var class="var">plaintext</var>, gnutls_datum_t * <var class="var">ciphertext</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fencrypt_005fdata"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: Holds the public key
</p>
<p><var class="var">flags</var>: should be 0 for now
</p>
<p><var class="var">plaintext</var>: The data to be encrypted
</p>
<p><var class="var">ciphertext</var>: contains the encrypted data
</p>
<p>This function will encrypt the given data, using the public
key. On success the  <code class="code">ciphertext</code> will be allocated using <code class="code">gnutls_malloc()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>





<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fsign_005fdata"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_sign_data</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">signer</var>, gnutls_digest_algorithm_t <var class="var">hash</var>, unsigned int <var class="var">flags</var>, const gnutls_datum_t * <var class="var">data</var>, gnutls_datum_t * <var class="var">signature</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fsign_005fdata"> &para;</a></span></dt>
<dd><p><var class="var">signer</var>: Holds the key
</p>
<p><var class="var">hash</var>: should be a digest algorithm
</p>
<p><var class="var">flags</var>: Zero or one of <code class="code">gnutls_privkey_flags_t</code> 
</p>
<p><var class="var">data</var>: holds the data to be signed
</p>
<p><var class="var">signature</var>: will contain the signature allocated with <code class="code">gnutls_malloc()</code> 
</p>
<p>This function will sign the given data using a signature algorithm
supported by the private key. Signature algorithms are always used
together with a hash functions.  Different hash functions may be
used for the RSA algorithm, but only the SHA family for the DSA keys.
</p>
<p>You may use <code class="code">gnutls_pubkey_get_preferred_hash_algorithm()</code>  to determine
the hash algorithm.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fsign_005fhash"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_sign_hash</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">signer</var>, gnutls_digest_algorithm_t <var class="var">hash_algo</var>, unsigned int <var class="var">flags</var>, const gnutls_datum_t * <var class="var">hash_data</var>, gnutls_datum_t * <var class="var">signature</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fsign_005fhash"> &para;</a></span></dt>
<dd><p><var class="var">signer</var>: Holds the signer&rsquo;s key
</p>
<p><var class="var">hash_algo</var>: The hash algorithm used
</p>
<p><var class="var">flags</var>: Zero or one of <code class="code">gnutls_privkey_flags_t</code> 
</p>
<p><var class="var">hash_data</var>: holds the data to be signed
</p>
<p><var class="var">signature</var>: will contain newly allocated signature
</p>
<p>This function will sign the given hashed data using a signature algorithm
supported by the private key. Signature algorithms are always used
together with a hash functions.  Different hash functions may be
used for the RSA algorithm, but only SHA-XXX for the DSA keys.
</p>
<p>You may use <code class="code">gnutls_pubkey_get_preferred_hash_algorithm()</code>  to determine
the hash algorithm.
</p>
<p>The flags may be <code class="code">GNUTLS_PRIVKEY_SIGN_FLAG_TLS1_RSA</code>  or <code class="code">GNUTLS_PRIVKEY_SIGN_FLAG_RSA_PSS</code> .
In the former case this function will ignore  <code class="code">hash_algo</code> and perform a raw PKCS1 signature,
and in the latter an RSA-PSS signature will be generated.
</p>
<p>Note that, not all algorithm support signing already hashed data. When
signing with Ed25519, <code class="code">gnutls_privkey_sign_data()</code>  should be used.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fdecrypt_005fdata"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_decrypt_data</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">key</var>, unsigned int <var class="var">flags</var>, const gnutls_datum_t * <var class="var">ciphertext</var>, gnutls_datum_t * <var class="var">plaintext</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fdecrypt_005fdata"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: Holds the key
</p>
<p><var class="var">flags</var>: zero for now
</p>
<p><var class="var">ciphertext</var>: holds the data to be decrypted
</p>
<p><var class="var">plaintext</var>: will contain the decrypted data, allocated with <code class="code">gnutls_malloc()</code> 
</p>
<p>This function will decrypt the given data using the algorithm
supported by the private key.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<p>Signing existing structures, such as certificates, CRLs,
or certificate requests, as well as associating public
keys with structures is also possible using the 
key abstractions.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fset_005fpubkey"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_set_pubkey</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, gnutls_pubkey_t <var class="var">key</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fset_005fpubkey"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: should contain a <code class="code">gnutls_x509_crq_t</code>  type
</p>
<p><var class="var">key</var>: holds a public key
</p>
<p>This function will set the public parameters from the given public
key to the request. The  <code class="code">key</code> can be deallocated after that.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fset_005fpubkey"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_set_pubkey</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, gnutls_pubkey_t <var class="var">key</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fset_005fpubkey"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">key</var>: holds a public key
</p>
<p>This function will set the public parameters from the given public
key to the certificate. The  <code class="code">key</code> can be deallocated after that.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrt_005fprivkey_005fsign">gnutls_x509_crt_privkey_sign</a> (gnutls_x509_crt_t <var class="var">crt</var>, gnutls_x509_crt_t <var class="var">issuer</var>, gnutls_privkey_t <var class="var">issuer_key</var>, gnutls_digest_algorithm_t <var class="var">dig</var>, unsigned int <var class="var">flags</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrl_005fprivkey_005fsign">gnutls_x509_crl_privkey_sign</a> (gnutls_x509_crl_t <var class="var">crl</var>, gnutls_x509_crt_t <var class="var">issuer</var>, gnutls_privkey_t <var class="var">issuer_key</var>, gnutls_digest_algorithm_t <var class="var">dig</var>, unsigned int <var class="var">flags</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrq_005fprivkey_005fsign">gnutls_x509_crq_privkey_sign</a> (gnutls_x509_crq_t <var class="var">crq</var>, gnutls_privkey_t <var class="var">key</var>, gnutls_digest_algorithm_t <var class="var">dig</var>, unsigned int <var class="var">flags</var>)</code></dt>
</dl>


<hr>
</div>
</div>
<div class="section-level-extent" id="Application_002dspecific-keys">
<div class="nav-panel">
<p>
Next: <a href="#Smart-cards-and-HSMs" accesskey="n" rel="next">Smart cards and HSMs</a>, Previous: <a href="#Abstract-key-types" accesskey="p" rel="prev">Abstract key types</a>, Up: <a href="#Hardware-security-modules-and-abstract-key-types" accesskey="u" rel="up">Abstract key types and Hardware security modules</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="System-and-application_002dspecific-keys"><span>5.2 System and application-specific keys<a class="copiable-link" href="#System-and-application_002dspecific-keys"> &para;</a></span></h3>
<a class="index-entry-id" id="index-Application_002dspecific-keys"></a>
<a class="index-entry-id" id="index-System_002dspecific-keys"></a>

<ul class="mini-toc">
<li><a href="#System_002dspecific-keys" accesskey="1">System-specific keys</a></li>
<li><a href="#Application_002dspecific-keys-1" accesskey="2">Application-specific keys</a></li>
</ul>
<div class="subsection-level-extent" id="System_002dspecific-keys">
<h4 class="subsection"><span>5.2.1 System-specific keys<a class="copiable-link" href="#System_002dspecific-keys"> &para;</a></span></h4>
<p>In several systems there are keystores which allow to read, store and use certificates
and private keys. For these systems GnuTLS provides the system-key API in <code class="code">gnutls/system-keys.h</code>.
That API provides the ability to iterate through all stored keys, add and delete keys as well
as use these keys using a URL which starts with &quot;system:&quot;. The format of the URLs is system-specific.
The <code class="code">systemkey</code> tool is also provided to assist in listing keys and debugging.
</p>
<p>The systems supported via this API are the following.
</p><ul class="itemize mark-bullet">
<li>Windows Cryptography API (CNG)
</li></ul>





<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsystem_005fkey_005fiter_005fget_005finfo"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_system_key_iter_get_info</strong> <code class="def-code-arguments">(gnutls_system_key_iter_t * <var class="var">iter</var>, unsigned <var class="var">cert_type</var>, char ** <var class="var">cert_url</var>, char ** <var class="var">key_url</var>, char ** <var class="var">label</var>, gnutls_datum_t * <var class="var">der</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fsystem_005fkey_005fiter_005fget_005finfo"> &para;</a></span></dt>
<dd><p><var class="var">iter</var>: an iterator of the system keys (must be set to <code class="code">NULL</code>  initially)
</p>
<p><var class="var">cert_type</var>: A value of gnutls_certificate_type_t which indicates the type of certificate to look for
</p>
<p><var class="var">cert_url</var>: The certificate URL of the pair (may be <code class="code">NULL</code> )
</p>
<p><var class="var">key_url</var>: The key URL of the pair (may be <code class="code">NULL</code> )
</p>
<p><var class="var">label</var>: The friendly name (if any) of the pair (may be <code class="code">NULL</code> )
</p>
<p><var class="var">der</var>: if non-NULL the DER data of the certificate
</p>
<p><var class="var">flags</var>: should be zero
</p>
<p>This function will return on each call a certificate
and key pair URLs, as well as a label associated with them,
and the DER-encoded certificate. When the iteration is complete it will
return <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> .
</p>
<p>Typically  <code class="code">cert_type</code> should be <code class="code">GNUTLS_CRT_X509</code> .
</p>
<p>All values set are allocated and must be cleared using <code class="code">gnutls_free()</code> ,
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<dl class="table">
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fsystem_005fkey_005fiter_005fdeinit">gnutls_system_key_iter_deinit</a> (gnutls_system_key_iter_t <var class="var">iter</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fsystem_005fkey_005fadd_005fx509">gnutls_system_key_add_x509</a> (gnutls_x509_crt_t <var class="var">crt</var>, gnutls_x509_privkey_t <var class="var">privkey</var>, const char * <var class="var">label</var>, char ** <var class="var">cert_url</var>, char ** <var class="var">key_url</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fsystem_005fkey_005fdelete">gnutls_system_key_delete</a> (const char * <var class="var">cert_url</var>, const char * <var class="var">key_url</var>)</code></dt>
</dl>

</div>
<div class="subsection-level-extent" id="Application_002dspecific-keys-1">
<h4 class="subsection"><span>5.2.2 Application-specific keys<a class="copiable-link" href="#Application_002dspecific-keys-1"> &para;</a></span></h4>
<p>For systems where GnuTLS doesn&rsquo;t provide a system specific store,
it may often be desirable to define a custom class of keys
that are identified via URLs and available to GnuTLS calls such as <a class="ref" href="#gnutls_005fcertificate_005fset_005fx509_005fkey_005ffile2">gnutls_certificate_set_x509_key_file2</a>.
Such keys can be registered using the API in <code class="code">gnutls/urls.h</code>. The function
which registers such keys is <a class="ref" href="#gnutls_005fregister_005fcustom_005furl">gnutls_register_custom_url</a>.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fregister_005fcustom_005furl"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_register_custom_url</strong> <code class="def-code-arguments">(const gnutls_custom_url_st * <var class="var">st</var>)</code><a class="copiable-link" href="#index-gnutls_005fregister_005fcustom_005furl"> &para;</a></span></dt>
<dd><p><var class="var">st</var>: A <code class="code">gnutls_custom_url_st</code>  structure
</p>
<p>Register a custom URL. This will affect the following functions:
<code class="code">gnutls_url_is_supported()</code> , <code class="code">gnutls_privkey_import_url()</code> ,
gnutls_pubkey_import_url, <code class="code">gnutls_x509_crt_import_url()</code>  
and all functions that depend on
them, e.g., <code class="code">gnutls_certificate_set_x509_key_file2()</code> .
</p>
<p>The provided structure and callback functions must be valid throughout
the lifetime of the process. The registration of an existing URL type
will fail with <code class="code">GNUTLS_E_INVALID_REQUEST</code> . Since GnuTLS 3.5.0 this function
can be used to override the builtin URLs.
</p>
<p>This function is not thread safe.
</p>
<p><strong class="strong">Returns:</strong> returns zero if the given structure was imported or a negative value otherwise.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<p>The input to this function are three callback functions as well as
the prefix of the URL, (e.g., &quot;mypkcs11:&quot;) and the length of the prefix.
The types of the callbacks are shown below, and are expected to
use the exported gnutls functions to import the keys and certificates.
E.g., a typical <code class="code">import_key</code> callback should use <a class="ref" href="#gnutls_005fprivkey_005fimport_005fext4">gnutls_privkey_import_ext4</a>.
</p>
<div class="example">
<pre class="example-preformatted">typedef int (*gnutls_privkey_import_url_func)(gnutls_privkey_t pkey,
                                              const char *url,
                                              unsigned flags);

typedef int (*gnutls_x509_crt_import_url_func)(gnutls_x509_crt_t pkey,
                                               const char *url,
                                               unsigned flags);

/* The following callbacks are optional */

/* This is to enable gnutls_pubkey_import_url() */
typedef int (*gnutls_pubkey_import_url_func)(gnutls_pubkey_t pkey,
					     const char *url, unsigned flags);

/* This is to allow constructing a certificate chain. It will be provided
 * the initial certificate URL and the certificate to find its issuer, and must
 * return zero and the DER encoding of the issuer's certificate. If not available,
 * it should return GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE. */
typedef int (*gnutls_get_raw_issuer_func)(const char *url, gnutls_x509_crt_t crt,
					  gnutls_datum_t *issuer_der, unsigned flags);

typedef struct custom_url_st {
        const char *name;
        unsigned name_size;
        gnutls_privkey_import_url_func import_key;
        gnutls_x509_crt_import_url_func import_crt;
        gnutls_pubkey_import_url_func import_pubkey;
	gnutls_get_raw_issuer_func get_issuer;
} gnutls_custom_url_st;
</pre></div>



<hr>
</div>
</div>
<div class="section-level-extent" id="Smart-cards-and-HSMs">
<div class="nav-panel">
<p>
Next: <a href="#Trusted-Platform-Module" accesskey="n" rel="next">Trusted Platform Module (TPM)</a>, Previous: <a href="#Application_002dspecific-keys" accesskey="p" rel="prev">System and application-specific keys</a>, Up: <a href="#Hardware-security-modules-and-abstract-key-types" accesskey="u" rel="up">Abstract key types and Hardware security modules</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Smart-cards-and-HSMs-1"><span>5.3 Smart cards and HSMs<a class="copiable-link" href="#Smart-cards-and-HSMs-1"> &para;</a></span></h3>
<a class="index-entry-id" id="index-PKCS-_002311-tokens"></a>
<a class="index-entry-id" id="index-hardware-tokens"></a>
<a class="index-entry-id" id="index-hardware-security-modules"></a>
<a class="index-entry-id" id="index-smart-cards"></a>

<p>In this section we present the smart-card and hardware security module (HSM) support 
in <abbr class="acronym">GnuTLS</abbr> using <abbr class="acronym">PKCS</abbr> #11 [<a class="ref" href="#PKCS11">PKCS11</a>]. Hardware security
modules and smart cards provide a way to store private keys and perform
operations on them without exposing them. This decouples cryptographic
keys from the applications that use them and provide an additional 
security layer against cryptographic key extraction.
Since this can also be achieved in software components such as in Gnome keyring,
we will use the term security module to describe any cryptographic key 
separation subsystem.
</p>
<p><abbr class="acronym">PKCS</abbr> #11 is plugin API allowing applications to access cryptographic
operations on a security module, as well as to objects residing on it. PKCS
#11 modules exist for hardware tokens such as smart cards<a class="footnote" id="DOCF9" href="#FOOT9"><sup>9</sup></a>,
cryptographic tokens, as well as for software modules like <abbr class="acronym">Gnome Keyring</abbr>. 
The objects residing on a security module may be certificates, public keys, 
private keys or secret keys. Of those certificates and public/private key 
pairs can be used with <abbr class="acronym">GnuTLS</abbr>. PKCS #11&rsquo;s main advantage is that 
it allows operations on private key objects such as decryption
and signing without exposing the key. In GnuTLS the PKCS #11 functionality is
available in <code class="code">gnutls/pkcs11.h</code>.
</p>
<div class="float" id="fig_002dpkcs11_002dvision">
<img class="image" src="pkcs11-vision.png" alt="pkcs11-vision">
<div class="caption"><p><strong class="strong">Figure 5.1: </strong>PKCS #11 module usage.</p></div></div>

<ul class="mini-toc">
<li><a href="#PKCS11-Initialization" accesskey="1">Initialization</a></li>
<li><a href="#PKCS11-Manual-Initialization" accesskey="2">Manual initialization of user-specific modules</a></li>
<li><a href="#Accessing-objects-that-require-a-PIN" accesskey="3">Accessing objects that require a PIN</a></li>
<li><a href="#Reading-objects" accesskey="4">Reading objects</a></li>
<li><a href="#Writing-objects" accesskey="5">Writing objects</a></li>
<li><a href="#PKCS11-Low-Level-Access" accesskey="6">Low Level Access</a></li>
<li><a href="#Using-a-PKCS11-token-with-TLS" accesskey="7">Using a <abbr class="acronym">PKCS</abbr> #11 token with TLS</a></li>
<li><a href="#Verifying-certificates-over-PKCS11" accesskey="8">Verifying certificates over <abbr class="acronym">PKCS</abbr> #11</a></li>
<li><a href="#p11tool-Invocation" accesskey="9">Invoking p11tool</a></li>
</ul>
<hr>
<div class="subsection-level-extent" id="PKCS11-Initialization">
<div class="nav-panel">
<p>
Next: <a href="#PKCS11-Manual-Initialization" accesskey="n" rel="next">Manual initialization of user-specific modules</a>, Up: <a href="#Smart-cards-and-HSMs" accesskey="u" rel="up">Smart cards and HSMs</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Initialization-1"><span>5.3.1 Initialization<a class="copiable-link" href="#Initialization-1"> &para;</a></span></h4>
<p>To allow all <abbr class="acronym">GnuTLS</abbr> applications to transparently access smart cards
and tokens, <abbr class="acronym">PKCS</abbr> #11 is automatically initialized during the first
call of a <abbr class="acronym">PKCS</abbr> #11 related function, in a thread safe way.
The default initialization process, utilizes p11-kit configuration, and loads any
appropriate <abbr class="acronym">PKCS</abbr> #11 modules. The p11-kit configuration
files<a class="footnote" id="DOCF10" href="#FOOT10"><sup>10</sup></a> are typically stored in <code class="code">/etc/pkcs11/modules/</code>.
For example a file that will instruct GnuTLS to load the <abbr class="acronym">OpenSC</abbr> module,
could be named <code class="code">/etc/pkcs11/modules/opensc.module</code> and contain the following:
</p>
<div class="example">
<pre class="example-preformatted">module: /usr/lib/opensc-pkcs11.so
</pre></div>

<p>If you use these configuration files, then there is no need for other initialization in
<abbr class="acronym">GnuTLS</abbr>, except for the PIN and token callbacks (see next section).
In several cases, however, it is desirable to limit badly behaving modules
(e.g., modules that add an unacceptable delay on initialization)
to single applications. That can be done using the &ldquo;enable-in:&rdquo; option
followed by the base name of applications that this module should be used.
</p>
<p>It is also possible to manually initialize or even disable the PKCS #11 subsystem if the 
default settings are not desirable or not available (see <a class="ref" href="#PKCS11-Manual-Initialization">Manual initialization of user-specific modules</a>
for more information).
</p>
<p>Note that, PKCS #11 modules behave in a peculiar way after a fork; they
require a reinitialization of all the used PKCS #11 resources.
While GnuTLS automates that process, there are corner cases where
it is not possible to handle it correctly in an automated way<a class="footnote" id="DOCF11" href="#FOOT11"><sup>11</sup></a>. For that, it is
recommended not to mix fork() and PKCS #11 module usage. It is recommended
to initialize and use any PKCS #11 resources in a single process.
</p>
<p>Older versions of <abbr class="acronym">GnuTLS</abbr> required to call <a class="ref" href="#gnutls_005fpkcs11_005freinit">gnutls_pkcs11_reinit</a>
after a fork() call; since 3.3.0 this is no longer required.
</p>

<hr>
</div>
<div class="subsection-level-extent" id="PKCS11-Manual-Initialization">
<div class="nav-panel">
<p>
Next: <a href="#Accessing-objects-that-require-a-PIN" accesskey="n" rel="next">Accessing objects that require a PIN</a>, Previous: <a href="#PKCS11-Initialization" accesskey="p" rel="prev">Initialization</a>, Up: <a href="#Smart-cards-and-HSMs" accesskey="u" rel="up">Smart cards and HSMs</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Manual-initialization-of-user_002dspecific-modules"><span>5.3.2 Manual initialization of user-specific modules<a class="copiable-link" href="#Manual-initialization-of-user_002dspecific-modules"> &para;</a></span></h4>

<p>In systems where one cannot rely on a globally available p11-kit configuration
to be available, it is still possible to utilize PKCS #11 objects. That
can be done by loading directly the PKCS #11 shared module in the
application using <a class="ref" href="#gnutls_005fpkcs11_005fadd_005fprovider">gnutls_pkcs11_add_provider</a>, after having
called <a class="ref" href="#gnutls_005fpkcs11_005finit">gnutls_pkcs11_init</a> specifying the <code class="code">GNUTLS_PKCS11_FLAG_MANUAL</code>
flag.
</p>



<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fadd_005fprovider"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_add_provider</strong> <code class="def-code-arguments">(const char * <var class="var">name</var>, const char * <var class="var">params</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fadd_005fprovider"> &para;</a></span></dt>
<dd><p><var class="var">name</var>: The filename of the module
</p>
<p><var class="var">params</var>: should be NULL or a known string (see description)
</p>
<p>This function will load and add a PKCS 11 module to the module
list used in gnutls. After this function is called the module will
be used for PKCS 11 operations.
</p>
<p>When loading a module to be used for certificate verification,
use the string &rsquo;trusted&rsquo; as  <code class="code">params</code> .
</p>
<p>Note that this function is not thread safe.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<p>In that case, the application will only have access to the modules explicitly
loaded. If the <code class="code">GNUTLS_PKCS11_FLAG_MANUAL</code> flag is specified and no calls
to <a class="ref" href="#gnutls_005fpkcs11_005fadd_005fprovider">gnutls_pkcs11_add_provider</a> are made, then the PKCS #11 functionality
is effectively disabled.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005finit"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_init</strong> <code class="def-code-arguments">(unsigned int <var class="var">flags</var>, const char * <var class="var">deprecated_config_file</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005finit"> &para;</a></span></dt>
<dd><p><var class="var">flags</var>: An ORed sequence of <code class="code">GNUTLS_PKCS11_FLAG_</code> *
</p>
<p><var class="var">deprecated_config_file</var>: either NULL or the location of a deprecated
configuration file
</p>
<p>This function will initialize the PKCS 11 subsystem in gnutls. It will
read configuration files if <code class="code">GNUTLS_PKCS11_FLAG_AUTO</code>  is used or allow
you to independently load PKCS 11 modules using <code class="code">gnutls_pkcs11_add_provider()</code> 
if <code class="code">GNUTLS_PKCS11_FLAG_MANUAL</code>  is specified.
</p>
<p>You don&rsquo;t need to call this function since GnuTLS 3.3.0 because it is being called
during the first request PKCS 11 operation. That call will assume the <code class="code">GNUTLS_PKCS11_FLAG_AUTO</code> 
flag. If another flags are required then it must be called independently
prior to any PKCS 11 operation.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>


<hr>
</div>
<div class="subsection-level-extent" id="Accessing-objects-that-require-a-PIN">
<div class="nav-panel">
<p>
Next: <a href="#Reading-objects" accesskey="n" rel="next">Reading objects</a>, Previous: <a href="#PKCS11-Manual-Initialization" accesskey="p" rel="prev">Manual initialization of user-specific modules</a>, Up: <a href="#Smart-cards-and-HSMs" accesskey="u" rel="up">Smart cards and HSMs</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Accessing-objects-that-require-a-PIN-1"><span>5.3.3 Accessing objects that require a PIN<a class="copiable-link" href="#Accessing-objects-that-require-a-PIN-1"> &para;</a></span></h4>

<p>Objects stored in token such as a private keys are typically protected
from access by a PIN or password. This PIN may be required to either read
the object (if allowed) or to perform operations with it. To allow obtaining
the PIN when accessing a protected object, as well as probe
the user to insert the token the following functions allow to set a callback.
</p>
<dl class="table">
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fpkcs11_005fset_005ftoken_005ffunction">gnutls_pkcs11_set_token_function</a> (gnutls_pkcs11_token_callback_t <var class="var">fn</var>, void * <var class="var">userdata</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fpkcs11_005fset_005fpin_005ffunction">gnutls_pkcs11_set_pin_function</a> (gnutls_pin_callback_t <var class="var">fn</var>, void * <var class="var">userdata</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpkcs11_005fadd_005fprovider">gnutls_pkcs11_add_provider</a> (const char * <var class="var">name</var>, const char * <var class="var">params</var>)</code></dt>
<dt><code class="code"><var class="var">gnutls_pin_callback_t</var> <a class="ref" href="#gnutls_005fpkcs11_005fget_005fpin_005ffunction">gnutls_pkcs11_get_pin_function</a> (void ** <var class="var">userdata</var>)</code></dt>
</dl>

<p>The callback is of type <code class="code">gnutls_pin_callback_t</code> and will have as
input the provided userdata, the PIN attempt number, a URL describing the
token, a label describing the object and flags. The PIN must be at most 
of <code class="code">pin_max</code> size and must be copied to pin variable. The function must
return 0 on success or a negative error code otherwise.
</p>
<pre class="verbatim">typedef int (*gnutls_pin_callback_t) (void *userdata, int attempt,
                                      const char *token_url,
                                      const char *token_label,
                                      unsigned int flags,
                                      char *pin, size_t pin_max);
</pre>
<p>The flags are of <code class="code">gnutls_pin_flag_t</code> type and are explained below.
</p>
<div class="float" id="gnutls_005fpin_005fflag_005ft">


<dl class="table">
<dt><code class="code">GNUTLS_PIN_USER</code></dt>
<dd><p>The PIN for the user.
</p></dd>
<dt><code class="code">GNUTLS_PIN_SO</code></dt>
<dd><p>The PIN for the security officer (admin).
</p></dd>
<dt><code class="code">GNUTLS_PIN_FINAL_TRY</code></dt>
<dd><p>This is the final try before blocking.
</p></dd>
<dt><code class="code">GNUTLS_PIN_COUNT_LOW</code></dt>
<dd><p>Few tries remain before token blocks.
</p></dd>
<dt><code class="code">GNUTLS_PIN_CONTEXT_SPECIFIC</code></dt>
<dd><p>The PIN is for a specific action and key like signing.
</p></dd>
<dt><code class="code">GNUTLS_PIN_WRONG</code></dt>
<dd><p>Last given PIN was not correct.
</p></dd>
</dl>
<div class="caption"><p><strong class="strong">Figure 5.2: </strong>The <code class="code">gnutls_pin_flag_t</code> enumeration.</p></div></div>
<p>Note that due to limitations of <abbr class="acronym">PKCS</abbr> #11 there are issues when multiple libraries 
are sharing a module. To avoid this problem GnuTLS uses <abbr class="acronym">p11-kit</abbr>
that provides a middleware to control access to resources over the
multiple users.
</p>
<p>To avoid conflicts with multiple registered callbacks for PIN functions,
<a class="ref" href="#gnutls_005fpkcs11_005fget_005fpin_005ffunction">gnutls_pkcs11_get_pin_function</a> may be used to check for any previously
set functions. In addition context specific PIN functions are allowed, e.g., by
using functions below.
</p>
<dl class="table">
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fcertificate_005fset_005fpin_005ffunction">gnutls_certificate_set_pin_function</a> (gnutls_certificate_credentials_t <var class="var">cred</var>, gnutls_pin_callback_t <var class="var">fn</var>, void * <var class="var">userdata</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fpubkey_005fset_005fpin_005ffunction">gnutls_pubkey_set_pin_function</a> (gnutls_pubkey_t <var class="var">key</var>, gnutls_pin_callback_t <var class="var">fn</var>, void * <var class="var">userdata</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fprivkey_005fset_005fpin_005ffunction">gnutls_privkey_set_pin_function</a> (gnutls_privkey_t <var class="var">key</var>, gnutls_pin_callback_t <var class="var">fn</var>, void * <var class="var">userdata</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fpkcs11_005fobj_005fset_005fpin_005ffunction">gnutls_pkcs11_obj_set_pin_function</a> (gnutls_pkcs11_obj_t <var class="var">obj</var>, gnutls_pin_callback_t <var class="var">fn</var>, void * <var class="var">userdata</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fx509_005fcrt_005fset_005fpin_005ffunction">gnutls_x509_crt_set_pin_function</a> (gnutls_x509_crt_t <var class="var">crt</var>, gnutls_pin_callback_t <var class="var">fn</var>, void * <var class="var">userdata</var>)</code></dt>
</dl>

<hr>
</div>
<div class="subsection-level-extent" id="Reading-objects">
<div class="nav-panel">
<p>
Next: <a href="#Writing-objects" accesskey="n" rel="next">Writing objects</a>, Previous: <a href="#Accessing-objects-that-require-a-PIN" accesskey="p" rel="prev">Accessing objects that require a PIN</a>, Up: <a href="#Smart-cards-and-HSMs" accesskey="u" rel="up">Smart cards and HSMs</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Reading-objects-1"><span>5.3.4 Reading objects<a class="copiable-link" href="#Reading-objects-1"> &para;</a></span></h4>

<p>All <abbr class="acronym">PKCS</abbr> #11 objects are referenced by <abbr class="acronym">GnuTLS</abbr> functions by
URLs as described in [<a class="ref" href="#PKCS11URI">PKCS11URI</a>]. 
This allows for a consistent naming of objects across systems and applications
in the same system. For example a public
key on a smart card may be referenced as:
</p>
<div class="example">
<pre class="example-preformatted">pkcs11:token=Nikos;serial=307521161601031;model=PKCS%2315; \
manufacturer=EnterSafe;object=test1;type=public;\
id=32f153f3e37990b08624141077ca5dec2d15faed
</pre></div>

<p>while the smart card itself can be referenced as:
</p><div class="example">
<pre class="example-preformatted">pkcs11:token=Nikos;serial=307521161601031;model=PKCS%2315;manufacturer=EnterSafe
</pre></div>

<p>Objects stored in a <abbr class="acronym">PKCS</abbr> #11 token can typically be extracted
if they are not marked as sensitive. Usually only private keys are marked as
sensitive and cannot be extracted, while certificates and other data can
be retrieved. The functions that can be used to enumerate and access objects
are shown below.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpkcs11_005fobj_005flist_005fimport_005furl4">gnutls_pkcs11_obj_list_import_url4</a> (gnutls_pkcs11_obj_t ** <var class="var">p_list</var>, unsigned int * <var class="var">n_list</var>, const char * <var class="var">url</var>, unsigned int <var class="var">flags</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpkcs11_005fobj_005fimport_005furl">gnutls_pkcs11_obj_import_url</a> (gnutls_pkcs11_obj_t <var class="var">obj</var>, const char * <var class="var">url</var>, unsigned int <var class="var">flags</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpkcs11_005fobj_005fexport_005furl">gnutls_pkcs11_obj_export_url</a> (gnutls_pkcs11_obj_t <var class="var">obj</var>, gnutls_pkcs11_url_type_t <var class="var">detailed</var>, char ** <var class="var">url</var>)</code></dt>
</dl>





<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fobj_005fget_005finfo"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_obj_get_info</strong> <code class="def-code-arguments">(gnutls_pkcs11_obj_t <var class="var">obj</var>, gnutls_pkcs11_obj_info_t <var class="var">itype</var>, void * <var class="var">output</var>, size_t * <var class="var">output_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fobj_005fget_005finfo"> &para;</a></span></dt>
<dd><p><var class="var">obj</var>: should contain a <code class="code">gnutls_pkcs11_obj_t</code>  type
</p>
<p><var class="var">itype</var>: Denotes the type of information requested
</p>
<p><var class="var">output</var>: where output will be stored
</p>
<p><var class="var">output_size</var>: contains the maximum size of the output buffer and will be
overwritten with the actual size.
</p>
<p>This function will return information about the PKCS11 certificate
such as the label, id as well as token information where the key is
stored.
</p>
<p>When output is text, a null terminated string is written to  <code class="code">output</code> and its
string length is written to  <code class="code">output_size</code> (without null terminator). If the
buffer is too small,  <code class="code">output_size</code> will contain the expected buffer size
(with null terminator for text) and return <code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code> .
</p>
<p>In versions previously to 3.6.0 this function included the null terminator
to  <code class="code">output_size</code> . After 3.6.0 the output size doesn&rsquo;t include the terminator character.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  (0) on success or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrt_005fimport_005fpkcs11">gnutls_x509_crt_import_pkcs11</a> (gnutls_x509_crt_t <var class="var">crt</var>, gnutls_pkcs11_obj_t <var class="var">pkcs11_crt</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrt_005fimport_005furl">gnutls_x509_crt_import_url</a> (gnutls_x509_crt_t <var class="var">crt</var>, const char * <var class="var">url</var>, unsigned int <var class="var">flags</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fx509_005fcrt_005flist_005fimport_005fpkcs11">gnutls_x509_crt_list_import_pkcs11</a> (gnutls_x509_crt_t * <var class="var">certs</var>, unsigned int <var class="var">cert_max</var>, gnutls_pkcs11_obj_t *const <var class="var">objs</var>, unsigned int <var class="var">flags</var>)</code></dt>
</dl>

<p>Properties of the physical token can also be accessed and altered with <abbr class="acronym">GnuTLS</abbr>.
For example data in a token can be erased (initialized), PIN can be altered, etc.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpkcs11_005ftoken_005finit">gnutls_pkcs11_token_init</a> (const char * <var class="var">token_url</var>, const char * <var class="var">so_pin</var>, const char * <var class="var">label</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpkcs11_005ftoken_005fget_005furl">gnutls_pkcs11_token_get_url</a> (unsigned int <var class="var">seq</var>, gnutls_pkcs11_url_type_t <var class="var">detailed</var>, char ** <var class="var">url</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpkcs11_005ftoken_005fget_005finfo">gnutls_pkcs11_token_get_info</a> (const char * <var class="var">url</var>, gnutls_pkcs11_token_info_t <var class="var">ttype</var>, void * <var class="var">output</var>, size_t * <var class="var">output_size</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpkcs11_005ftoken_005fget_005fflags">gnutls_pkcs11_token_get_flags</a> (const char * <var class="var">url</var>, unsigned int * <var class="var">flags</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpkcs11_005ftoken_005fset_005fpin">gnutls_pkcs11_token_set_pin</a> (const char * <var class="var">token_url</var>, const char * <var class="var">oldpin</var>, const char * <var class="var">newpin</var>, unsigned int <var class="var">flags</var>)</code></dt>
</dl>

<p>The following examples demonstrate the usage of the API. The first example
will list all available PKCS #11 tokens in a system and the latter will
list all certificates in a token that have a corresponding private key.
</p>
<div class="example">
<pre class="example-preformatted">int i;
char* url;

gnutls_global_init();

for (i=0;;i++) 
  {
    ret = gnutls_pkcs11_token_get_url(i, &amp;url);
    if (ret == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE)
      break;

    if (ret &lt; 0)
      exit(1);
		
    fprintf(stdout, &quot;Token[%d]: URL: %s\n&quot;, i, url);
    gnutls_free(url);
  }
gnutls_global_deinit();
</pre></div>

<pre class="verbatim">/* This example code is placed in the public domain. */

#include &lt;config.h&gt;
#include &lt;gnutls/gnutls.h&gt;
#include &lt;gnutls/pkcs11.h&gt;
#include &lt;stdio.h&gt;
#include &lt;stdlib.h&gt;

#define URL &quot;pkcs11:URL&quot;

int main(int argc, char **argv)
{
	gnutls_pkcs11_obj_t *obj_list;
	gnutls_x509_crt_t xcrt;
	unsigned int obj_list_size = 0;
	gnutls_datum_t cinfo;
	int ret;
	unsigned int i;

	ret = gnutls_pkcs11_obj_list_import_url4(
		&amp;obj_list, &amp;obj_list_size, URL,
		GNUTLS_PKCS11_OBJ_FLAG_CRT |
			GNUTLS_PKCS11_OBJ_FLAG_WITH_PRIVKEY);
	if (ret &lt; 0)
		return -1;

	/* now all certificates are in obj_list */
	for (i = 0; i &lt; obj_list_size; i++) {
		gnutls_x509_crt_init(&amp;xcrt);

		gnutls_x509_crt_import_pkcs11(xcrt, obj_list[i]);

		gnutls_x509_crt_print(xcrt, GNUTLS_CRT_PRINT_FULL, &amp;cinfo);

		fprintf(stdout, &quot;cert[%d]:\n %s\n\n&quot;, i, cinfo.data);

		gnutls_free(cinfo.data);
		gnutls_x509_crt_deinit(xcrt);
	}

	for (i = 0; i &lt; obj_list_size; i++)
		gnutls_pkcs11_obj_deinit(obj_list[i]);
	gnutls_free(obj_list);

	return 0;
}
</pre>
<hr>
</div>
<div class="subsection-level-extent" id="Writing-objects">
<div class="nav-panel">
<p>
Next: <a href="#PKCS11-Low-Level-Access" accesskey="n" rel="next">Low Level Access</a>, Previous: <a href="#Reading-objects" accesskey="p" rel="prev">Reading objects</a>, Up: <a href="#Smart-cards-and-HSMs" accesskey="u" rel="up">Smart cards and HSMs</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Writing-objects-1"><span>5.3.5 Writing objects<a class="copiable-link" href="#Writing-objects-1"> &para;</a></span></h4>

<p>With <abbr class="acronym">GnuTLS</abbr> you can copy existing private keys and certificates
to a token. Note that when copying private keys it is recommended to mark
them as sensitive using the <code class="code">GNUTLS_PKCS11_OBJ_FLAG_MARK_SENSITIVE</code>
to prevent its extraction. An object can be marked as private using the flag 
<code class="code">GNUTLS_PKCS11_OBJ_FLAG_MARK_PRIVATE</code>, to require PIN to be
entered before accessing the object (for operations or otherwise).
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fcopy_005fx509_005fprivkey2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_copy_x509_privkey2</strong> <code class="def-code-arguments">(const char * <var class="var">token_url</var>, gnutls_x509_privkey_t <var class="var">key</var>, const char * <var class="var">label</var>, const gnutls_datum_t * <var class="var">cid</var>, unsigned int <var class="var">key_usage</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fcopy_005fx509_005fprivkey2"> &para;</a></span></dt>
<dd><p><var class="var">token_url</var>: A PKCS <code class="code">11</code>  URL specifying a token
</p>
<p><var class="var">key</var>: A private key
</p>
<p><var class="var">label</var>: A name to be used for the stored data
</p>
<p><var class="var">cid</var>: The CKA_ID to set for the object -if NULL, the ID will be derived from the public key
</p>
<p><var class="var">key_usage</var>: One of GNUTLS_KEY_*
</p>
<p><var class="var">flags</var>: One of GNUTLS_PKCS11_OBJ_* flags
</p>
<p>This function will copy a private key into a PKCS <code class="code">11</code>  token specified by
a URL.
</p>
<p>Since 3.6.3 the objects are marked as sensitive by default unless
<code class="code">GNUTLS_PKCS11_OBJ_FLAG_MARK_NOT_SENSITIVE</code>  is specified.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>





<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fcopy_005fx509_005fcrt2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_copy_x509_crt2</strong> <code class="def-code-arguments">(const char * <var class="var">token_url</var>, gnutls_x509_crt_t <var class="var">crt</var>, const char * <var class="var">label</var>, const gnutls_datum_t * <var class="var">cid</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fcopy_005fx509_005fcrt2"> &para;</a></span></dt>
<dd><p><var class="var">token_url</var>: A PKCS <code class="code">11</code>  URL specifying a token
</p>
<p><var class="var">crt</var>: The certificate to copy
</p>
<p><var class="var">label</var>: The name to be used for the stored data
</p>
<p><var class="var">cid</var>: The CKA_ID to set for the object -if NULL, the ID will be derived from the public key
</p>
<p><var class="var">flags</var>: One of GNUTLS_PKCS11_OBJ_FLAG_*
</p>
<p>This function will copy a certificate into a PKCS <code class="code">11</code>  token specified by
a URL. Valid flags to mark the certificate: <code class="code">GNUTLS_PKCS11_OBJ_FLAG_MARK_TRUSTED</code> ,
<code class="code">GNUTLS_PKCS11_OBJ_FLAG_MARK_PRIVATE</code> , <code class="code">GNUTLS_PKCS11_OBJ_FLAG_MARK_CA</code> ,
<code class="code">GNUTLS_PKCS11_OBJ_FLAG_MARK_ALWAYS_AUTH</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fdelete_005furl"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_delete_url</strong> <code class="def-code-arguments">(const char * <var class="var">object_url</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fdelete_005furl"> &para;</a></span></dt>
<dd><p><var class="var">object_url</var>: The URL of the object to delete.
</p>
<p><var class="var">flags</var>: One of GNUTLS_PKCS11_OBJ_* flags
</p>
<p>This function will delete objects matching the given URL.
Note that not all tokens support the delete operation.
</p>
<p><strong class="strong">Returns:</strong> On success, the number of objects deleted is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>


<hr>
</div>
<div class="subsection-level-extent" id="PKCS11-Low-Level-Access">
<div class="nav-panel">
<p>
Next: <a href="#Using-a-PKCS11-token-with-TLS" accesskey="n" rel="next">Using a <abbr class="acronym">PKCS</abbr> #11 token with TLS</a>, Previous: <a href="#Writing-objects" accesskey="p" rel="prev">Writing objects</a>, Up: <a href="#Smart-cards-and-HSMs" accesskey="u" rel="up">Smart cards and HSMs</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Low-Level-Access"><span>5.3.6 Low Level Access<a class="copiable-link" href="#Low-Level-Access"> &para;</a></span></h4>

<p>When it is needed to use PKCS#11 functionality which is not wrapped by
GnuTLS, it is possible to extract the PKCS#11 session, object or token pointers.
That allows an application to still access the low-level functionality,
while at the same time take advantage of the URI addressing scheme supported
by GnuTLS.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005ftoken_005fget_005fptr"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_token_get_ptr</strong> <code class="def-code-arguments">(const char * <var class="var">url</var>, void ** <var class="var">ptr</var>, unsigned long * <var class="var">slot_id</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005ftoken_005fget_005fptr"> &para;</a></span></dt>
<dd><p><var class="var">url</var>: should contain a PKCS<code class="code">11</code>  URL identifying a token
</p>
<p><var class="var">ptr</var>: will contain the CK_FUNCTION_LIST_PTR pointer
</p>
<p><var class="var">slot_id</var>: will contain the slot_id (may be <code class="code">NULL</code> )
</p>
<p><var class="var">flags</var>: should be zero
</p>
<p>This function will return the function pointer of the specified
token by the URL. The returned pointers are valid until
gnutls is deinitialized, c.f. <code class="code">_global_deinit()</code> .
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  (0) on success or a negative error code
on error.
</p>
<p><strong class="strong">Since:</strong> 3.6.3
</p></dd></dl>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fobj_005fget_005fptr"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_obj_get_ptr</strong> <code class="def-code-arguments">(gnutls_pkcs11_obj_t <var class="var">obj</var>, void ** <var class="var">ptr</var>, void ** <var class="var">session</var>, void ** <var class="var">ohandle</var>, unsigned long * <var class="var">slot_id</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fobj_005fget_005fptr"> &para;</a></span></dt>
<dd><p><var class="var">obj</var>: should contain a <code class="code">gnutls_pkcs11_obj_t</code>  type
</p>
<p><var class="var">ptr</var>: will contain the CK_FUNCTION_LIST_PTR pointer (may be <code class="code">NULL</code> )
</p>
<p><var class="var">session</var>: will contain the CK_SESSION_HANDLE of the object
</p>
<p><var class="var">ohandle</var>: will contain the CK_OBJECT_HANDLE of the object
</p>
<p><var class="var">slot_id</var>: the identifier of the slot (may be <code class="code">NULL</code> )
</p>
<p><var class="var">flags</var>: Or sequence of GNUTLS_PKCS11_OBJ_* flags
</p>
<p>Obtains the PKCS<code class="code">11</code>  session handles of an object.  <code class="code">session</code> and  <code class="code">ohandle</code> must be deinitialized by the caller. The returned pointers are
independent of the  <code class="code">obj</code> lifetime.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  (0) on success or a negative error code
on error.
</p>
<p><strong class="strong">Since:</strong> 3.6.3
</p></dd></dl>


<hr>
</div>
<div class="subsection-level-extent" id="Using-a-PKCS11-token-with-TLS">
<div class="nav-panel">
<p>
Next: <a href="#Verifying-certificates-over-PKCS11" accesskey="n" rel="next">Verifying certificates over <abbr class="acronym">PKCS</abbr> #11</a>, Previous: <a href="#PKCS11-Low-Level-Access" accesskey="p" rel="prev">Low Level Access</a>, Up: <a href="#Smart-cards-and-HSMs" accesskey="u" rel="up">Smart cards and HSMs</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Using-a-PKCS-_002311-token-with-TLS"><span>5.3.7 Using a <abbr class="acronym">PKCS</abbr> #11 token with TLS<a class="copiable-link" href="#Using-a-PKCS-_002311-token-with-TLS"> &para;</a></span></h4>

<p>It is possible to use a <abbr class="acronym">PKCS</abbr> #11 token to a TLS
session, as shown in <a class="ref" href="#ex_002dpkcs11_002dclient">ex-pkcs11-client</a>. In addition
the following functions can be used to load PKCS #11 key and
certificates by specifying a PKCS #11 URL instead of a filename.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fcertificate_005fset_005fx509_005ftrust_005ffile">gnutls_certificate_set_x509_trust_file</a> (gnutls_certificate_credentials_t <var class="var">cred</var>, const char * <var class="var">cafile</var>, gnutls_x509_crt_fmt_t <var class="var">type</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fcertificate_005fset_005fx509_005fkey_005ffile2">gnutls_certificate_set_x509_key_file2</a> (gnutls_certificate_credentials_t <var class="var">res</var>, const char * <var class="var">certfile</var>, const char * <var class="var">keyfile</var>, gnutls_x509_crt_fmt_t <var class="var">type</var>, const char * <var class="var">pass</var>, unsigned int <var class="var">flags</var>)</code></dt>
</dl>


<hr>
</div>
<div class="subsection-level-extent" id="Verifying-certificates-over-PKCS11">
<div class="nav-panel">
<p>
Next: <a href="#p11tool-Invocation" accesskey="n" rel="next">Invoking p11tool</a>, Previous: <a href="#Using-a-PKCS11-token-with-TLS" accesskey="p" rel="prev">Using a <abbr class="acronym">PKCS</abbr> #11 token with TLS</a>, Up: <a href="#Smart-cards-and-HSMs" accesskey="u" rel="up">Smart cards and HSMs</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Verifying-certificates-over-PKCS-_002311"><span>5.3.8 Verifying certificates over <abbr class="acronym">PKCS</abbr> #11<a class="copiable-link" href="#Verifying-certificates-over-PKCS-_002311"> &para;</a></span></h4>

<p>The <abbr class="acronym">PKCS</abbr> #11 API can be used to allow all applications in the
same operating system to access shared cryptographic keys and certificates in a
uniform way, as in <a class="ref" href="#fig_002dpkcs11_002dvision">Figure 5.1</a>. That way applications could load their
trusted certificate list, as well as user certificates from a common PKCS #11 module.
Such a provider is the p11-kit trust storage module<a class="footnote" id="DOCF12" href="#FOOT12"><sup>12</sup></a>
and it provides access to the trusted Root CA certificates in a system. That
provides a more dynamic list of Root CA certificates, as opposed to a static
list in a file or directory.
</p>
<p>That store, allows for distrusting of CAs or certificates, as well as
categorization of the Root CAs (Web verification, Code signing, etc.), in
addition to restricting their purpose via stapled extensions<a class="footnote" id="DOCF13" href="#FOOT13"><sup>13</sup></a>.
GnuTLS will utilize the p11-kit trust module as the default trust store
if configured to; i.e., if &rsquo;&ndash;with-default-trust-store-pkcs11=pkcs11:&rsquo; is given to 
the configure script.
</p>

<hr>
</div>
<div class="subsection-level-extent" id="p11tool-Invocation">
<div class="nav-panel">
<p>
Previous: <a href="#Verifying-certificates-over-PKCS11" accesskey="p" rel="prev">Verifying certificates over <abbr class="acronym">PKCS</abbr> #11</a>, Up: <a href="#Smart-cards-and-HSMs" accesskey="u" rel="up">Smart cards and HSMs</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Invoking-p11tool"><span>5.3.9 Invoking p11tool<a class="copiable-link" href="#Invoking-p11tool"> &para;</a></span></h4>
<a class="index-entry-id" id="index-p11tool"></a>

<p>Program that allows operations on PKCS #11 smart cards
and security modules. 
</p>
<p>To use PKCS #11 tokens with GnuTLS the p11-kit configuration files need to be setup.
That is create a .module file in /etc/pkcs11/modules with the contents &rsquo;module: /path/to/pkcs11.so&rsquo;.
Alternatively the configuration file /etc/gnutls/pkcs11.conf has to exist and contain a number
of lines of the form &rsquo;load=/usr/lib/opensc-pkcs11.so&rsquo;.
</p>
<p>You can provide the PIN to be used for the PKCS #11 operations with the environment variables
GNUTLS_PIN and GNUTLS_SO_PIN.
</p>

<a class="anchor" id="p11tool-usage"></a><h4 class="subsubheading" id="p11tool-help_002fusage-_0028_002d_003f_0029"><span>p11tool help/usage (<samp class="option">-?</samp>)<a class="copiable-link" href="#p11tool-help_002fusage-_0028_002d_003f_0029"> &para;</a></span></h4>
<a class="index-entry-id" id="index-p11tool-help"></a>

<p>The text printed is the same whether selected with the <code class="code">help</code> option
(<samp class="option">--help</samp>) or the <code class="code">more-help</code> option (<samp class="option">--more-help</samp>).  <code class="code">more-help</code> will print
the usage text by passing it through a pager program.
<code class="code">more-help</code> is disabled on platforms without a working
<code class="code">fork(2)</code> function.  The <code class="code">PAGER</code> environment variable is
used to select the program, defaulting to <samp class="file">more</samp>.  Both will exit
with a status code of 0.
</p>
<div class="example">
<pre class="example-preformatted">p11tool - GnuTLS PKCS #11 tool
Usage:  p11tool [ -&lt;flag&gt; [&lt;val&gt;] | --&lt;name&gt;[{=| }&lt;val&gt;] ]... [url]

None:


Tokens:

       --list-tokens          List all available tokens
       --list-token-urls      List the URLs available tokens
       --list-mechanisms      List all available mechanisms in a token
       --initialize           Initializes a PKCS #11 token
       --initialize-pin       Initializes/Resets a PKCS #11 token user PIN
       --initialize-so-pin    Initializes/Resets a PKCS #11 token security officer PIN
       --set-pin=str          Specify the PIN to use on token operations
       --set-so-pin=str       Specify the Security Officer's PIN to use on token initialization

Object listing:

       --list-all             List all available objects in a token
       --list-all-certs       List all available certificates in a token
       --list-certs           List all certificates that have an associated private key
       --list-all-privkeys    List all available private keys in a token
       --list-privkeys        an alias for the 'list-all-privkeys' option
       --list-keys            an alias for the 'list-all-privkeys' option
       --list-all-trusted     List all available certificates marked as trusted
       --export               Export the object specified by the URL
				- prohibits these options:
				export-stapled
				export-chain
				export-pubkey
       --export-stapled       Export the certificate object specified by the URL
				- prohibits these options:
				export
				export-chain
				export-pubkey
       --export-chain         Export the certificate specified by the URL and its chain of trust
				- prohibits these options:
				export-stapled
				export
				export-pubkey
       --export-pubkey        Export the public key for a private key
				- prohibits these options:
				export-stapled
				export
				export-chain
       --info                 List information on an available object in a token
       --trusted              an alias for the 'mark-trusted' option
       --distrusted           an alias for the 'mark-distrusted' option

Key generation:

       --generate-privkey=str Generate private-public key pair of given type
       --bits=num             Specify the number of bits for the key generate
       --curve=str            Specify the curve used for EC key generation
       --sec-param=str        Specify the security level

Writing objects:

       --set-id=str           Set the CKA_ID (in hex) for the specified by the URL object
				- prohibits the option 'write'
       --set-label=str        Set the CKA_LABEL for the specified by the URL object
				- prohibits these options:
				write
				set-id
       --write                Writes the loaded objects to a PKCS #11 token
       --delete               Deletes the objects matching the given PKCS #11 URL
       --label=str            Sets a label for the write operation
       --id=str               Sets an ID for the write operation
       --mark-wrap            Marks the generated key to be a wrapping key
       --mark-trusted         Marks the object to be written as trusted
				- prohibits the option 'mark-distrusted'
       --mark-distrusted      When retrieving objects, it requires the objects to be distrusted
				- prohibits the option 'mark-trusted'
       --mark-decrypt         Marks the object to be written for decryption
       --mark-sign            Marks the object to be written for signature generation
       --mark-ca              Marks the object to be written as a CA
       --mark-private         Marks the object to be written as private
       --ca                   an alias for the 'mark-ca' option
       --private              an alias for the 'mark-private' option
       --mark-always-authenticate  Marks the object to be written as always authenticate
       --secret-key=str       Provide a hex encoded secret key
       --load-privkey=file    Private key file to use
				- file must pre-exist
       --load-pubkey=file     Public key file to use
				- file must pre-exist
       --load-certificate=file Certificate file to use
				- file must pre-exist

Other options:

   -d, --debug=num            Enable debugging
				- it must be in the range:
				  0 to 9999
       --outfile=str          Output file
       --login                Force (user) login to token
       --so-login             Force security officer login to token
       --admin-login          an alias for the 'so-login' option
       --test-sign            Tests the signature operation of the provided object
       --sign-params=str      Sign with a specific signature algorithm
       --hash=str             Hash algorithm to use for signing
       --generate-random=num  Generate random data
   -8, --pkcs8                Use PKCS #8 format for private keys
       --inder                Use DER/RAW format for input
       --inraw                an alias for the 'inder' option
       --outder               Use DER format for output certificates, private keys, and DH parameters
       --outraw               an alias for the 'outder' option
       --provider=file        Specify the PKCS #11 provider library
       --detailed-url         Print detailed URLs
       --only-urls            Print a compact listing using only the URLs
       --batch                Disable all interaction with the tool

Version, usage and configuration options:

   -v, --version[=arg]        output version information and exit
   -h, --help                 display extended usage information and exit
   -!, --more-help            extended usage information passed thru pager

Options are specified by doubled hyphens and their name or by a single
hyphen and the flag character.
Operands and options may be intermixed.  They will be reordered.

Program that allows operations on PKCS #11 smart cards
and security modules. 

To use PKCS #11 tokens with GnuTLS the p11-kit configuration files need to be setup.
That is create a .module file in /etc/pkcs11/modules with the contents 'module: /path/to/pkcs11.so'.
Alternatively the configuration file /etc/gnutls/pkcs11.conf has to exist and contain a number
of lines of the form 'load=/usr/lib/opensc-pkcs11.so'.

You can provide the PIN to be used for the PKCS #11 operations with the environment variables
GNUTLS_PIN and GNUTLS_SO_PIN.


Please send bug reports to:  &lt;bugs@gnutls.org&gt;

</pre></div>

<a class="anchor" id="p11tool-token_002drelated_002doptions"></a><h4 class="subsubheading" id="token_002drelated_002doptions-options"><span>token-related-options options<a class="copiable-link" href="#token_002drelated_002doptions-options"> &para;</a></span></h4>
<p>Tokens.
</p><h4 class="subsubheading" id="list_002dtoken_002durls-option_002e"><span>list-token-urls option.<a class="copiable-link" href="#list_002dtoken_002durls-option_002e"> &para;</a></span></h4>
<a class="anchor" id="p11tool-list_002dtoken_002durls"></a>
<p>This is the &ldquo;list the urls available tokens&rdquo; option.
This is a more compact version of &ndash;list-tokens.
</p><h4 class="subsubheading" id="initialize_002dso_002dpin-option_002e"><span>initialize-so-pin option.<a class="copiable-link" href="#initialize_002dso_002dpin-option_002e"> &para;</a></span></h4>
<a class="anchor" id="p11tool-initialize_002dso_002dpin"></a>
<p>This is the &ldquo;initializes/resets a pkcs #11 token security officer pin&rdquo; option.
This initializes the security officer&rsquo;s PIN. When used non-interactively use the GNUTLS_NEW_SO_PIN
environment variables to initialize SO&rsquo;s PIN.
</p><h4 class="subsubheading" id="set_002dpin-option_002e"><span>set-pin option.<a class="copiable-link" href="#set_002dpin-option_002e"> &para;</a></span></h4>
<a class="anchor" id="p11tool-set_002dpin"></a>
<p>This is the &ldquo;specify the pin to use on token operations&rdquo; option.
This option takes a ArgumentType.STRING argument.
Alternatively the GNUTLS_PIN environment variable may be used.
</p><h4 class="subsubheading" id="set_002dso_002dpin-option_002e"><span>set-so-pin option.<a class="copiable-link" href="#set_002dso_002dpin-option_002e"> &para;</a></span></h4>
<a class="anchor" id="p11tool-set_002dso_002dpin"></a>
<p>This is the &ldquo;specify the security officer&rsquo;s pin to use on token initialization&rdquo; option.
This option takes a ArgumentType.STRING argument.
Alternatively the GNUTLS_SO_PIN environment variable may be used.
<a class="anchor" id="p11tool-object_002dlist_002drelated_002doptions"></a></p><h4 class="subsubheading" id="object_002dlist_002drelated_002doptions-options"><span>object-list-related-options options<a class="copiable-link" href="#object_002dlist_002drelated_002doptions-options"> &para;</a></span></h4>
<p>Object listing.
</p><h4 class="subsubheading" id="list_002dall-option_002e"><span>list-all option.<a class="copiable-link" href="#list_002dall-option_002e"> &para;</a></span></h4>
<a class="anchor" id="p11tool-list_002dall"></a>
<p>This is the &ldquo;list all available objects in a token&rdquo; option.
All objects available in the token will be listed. That includes
objects which are potentially unaccessible using this tool.
</p><h4 class="subsubheading" id="list_002dall_002dcerts-option_002e"><span>list-all-certs option.<a class="copiable-link" href="#list_002dall_002dcerts-option_002e"> &para;</a></span></h4>
<a class="anchor" id="p11tool-list_002dall_002dcerts"></a>
<p>This is the &ldquo;list all available certificates in a token&rdquo; option.
That option will also provide more information on the
certificates, for example, expand the attached extensions in a trust
token (like p11-kit-trust).
</p><h4 class="subsubheading" id="list_002dcerts-option_002e"><span>list-certs option.<a class="copiable-link" href="#list_002dcerts-option_002e"> &para;</a></span></h4>
<a class="anchor" id="p11tool-list_002dcerts"></a>
<p>This is the &ldquo;list all certificates that have an associated private key&rdquo; option.
That option will only display certificates which have a private
key associated with them (share the same ID).
</p><h4 class="subsubheading" id="list_002dall_002dprivkeys-option_002e"><span>list-all-privkeys option.<a class="copiable-link" href="#list_002dall_002dprivkeys-option_002e"> &para;</a></span></h4>
<a class="anchor" id="p11tool-list_002dall_002dprivkeys"></a>
<p>This is the &ldquo;list all available private keys in a token&rdquo; option.
Lists all the private keys in a token that match the specified URL.
</p><h4 class="subsubheading" id="list_002dprivkeys-option_002e"><span>list-privkeys option.<a class="copiable-link" href="#list_002dprivkeys-option_002e"> &para;</a></span></h4>
<a class="anchor" id="p11tool-list_002dprivkeys"></a>
<p>This is an alias for the <code class="code">list-all-privkeys</code> option,
see <a class="pxref" href="#p11tool-list_002dall_002dprivkeys">the list-all-privkeys option documentation</a>.
</p>
<h4 class="subsubheading" id="list_002dkeys-option_002e"><span>list-keys option.<a class="copiable-link" href="#list_002dkeys-option_002e"> &para;</a></span></h4>
<a class="anchor" id="p11tool-list_002dkeys"></a>
<p>This is an alias for the <code class="code">list-all-privkeys</code> option,
see <a class="pxref" href="#p11tool-list_002dall_002dprivkeys">the list-all-privkeys option documentation</a>.
</p>
<h4 class="subsubheading" id="export_002dstapled-option_002e"><span>export-stapled option.<a class="copiable-link" href="#export_002dstapled-option_002e"> &para;</a></span></h4>
<a class="anchor" id="p11tool-export_002dstapled"></a>
<p>This is the &ldquo;export the certificate object specified by the url&rdquo; option.
</p>
<p>This option has some usage constraints.  It:
</p><ul class="itemize mark-bullet">
<li>must not appear in combination with any of the following options:
export, export-chain, export-pubkey.
</li></ul>

<p>Exports the certificate specified by the URL while including any attached extensions to it.
Since attached extensions are a p11-kit extension, this option is only
available on p11-kit registered trust modules.
</p><h4 class="subsubheading" id="export_002dchain-option_002e"><span>export-chain option.<a class="copiable-link" href="#export_002dchain-option_002e"> &para;</a></span></h4>
<a class="anchor" id="p11tool-export_002dchain"></a>
<p>This is the &ldquo;export the certificate specified by the url and its chain of trust&rdquo; option.
</p>
<p>This option has some usage constraints.  It:
</p><ul class="itemize mark-bullet">
<li>must not appear in combination with any of the following options:
export-stapled, export, export-pubkey.
</li></ul>

<p>Exports the certificate specified by the URL and generates its chain of trust based on the stored certificates in the module.
</p><h4 class="subsubheading" id="export_002dpubkey-option_002e"><span>export-pubkey option.<a class="copiable-link" href="#export_002dpubkey-option_002e"> &para;</a></span></h4>
<a class="anchor" id="p11tool-export_002dpubkey"></a>
<p>This is the &ldquo;export the public key for a private key&rdquo; option.
</p>
<p>This option has some usage constraints.  It:
</p><ul class="itemize mark-bullet">
<li>must not appear in combination with any of the following options:
export-stapled, export, export-chain.
</li></ul>

<p>Exports the public key for the specified private key
</p><h4 class="subsubheading" id="trusted-option_002e"><span>trusted option.<a class="copiable-link" href="#trusted-option_002e"> &para;</a></span></h4>
<a class="anchor" id="p11tool-trusted"></a>
<p>This is an alias for the <code class="code">mark-trusted</code> option,
see <a class="pxref" href="#p11tool-mark_002dtrusted">the mark-trusted option documentation</a>.
</p>
<h4 class="subsubheading" id="distrusted-option_002e"><span>distrusted option.<a class="copiable-link" href="#distrusted-option_002e"> &para;</a></span></h4>
<a class="anchor" id="p11tool-distrusted"></a>
<p>This is an alias for the <code class="code">mark-distrusted</code> option,
see <a class="pxref" href="#p11tool-mark_002ddistrusted">the mark-distrusted option documentation</a>.
</p>
<a class="anchor" id="p11tool-keygen_002drelated_002doptions"></a><h4 class="subsubheading" id="keygen_002drelated_002doptions-options"><span>keygen-related-options options<a class="copiable-link" href="#keygen_002drelated_002doptions-options"> &para;</a></span></h4>
<p>Key generation.
</p><h4 class="subsubheading" id="generate_002dprivkey-option_002e"><span>generate-privkey option.<a class="copiable-link" href="#generate_002dprivkey-option_002e"> &para;</a></span></h4>
<a class="anchor" id="p11tool-generate_002dprivkey"></a>
<p>This is the &ldquo;generate private-public key pair of given type&rdquo; option.
This option takes a ArgumentType.STRING argument.
Generates a private-public key pair in the specified token.
Acceptable types are RSA, ECDSA, Ed25519, and DSA. Should be combined with &ndash;sec-param or &ndash;bits.
</p><h4 class="subsubheading" id="generate_002drsa-option_002e"><span>generate-rsa option.<a class="copiable-link" href="#generate_002drsa-option_002e"> &para;</a></span></h4>
<a class="anchor" id="p11tool-generate_002drsa"></a>
<p>This is the &ldquo;generate an rsa private-public key pair&rdquo; option.
Generates an RSA private-public key pair on the specified token.
Should be combined with &ndash;sec-param or &ndash;bits.
</p>
<p><strong class="strong">NOTE</strong><strong class="strong">: THIS OPTION IS DEPRECATED</strong>
</p><h4 class="subsubheading" id="generate_002ddsa-option_002e"><span>generate-dsa option.<a class="copiable-link" href="#generate_002ddsa-option_002e"> &para;</a></span></h4>
<a class="anchor" id="p11tool-generate_002ddsa"></a>
<p>This is the &ldquo;generate a dsa private-public key pair&rdquo; option.
Generates a DSA private-public key pair on the specified token.
Should be combined with &ndash;sec-param or &ndash;bits.
</p>
<p><strong class="strong">NOTE</strong><strong class="strong">: THIS OPTION IS DEPRECATED</strong>
</p><h4 class="subsubheading" id="generate_002decc-option_002e"><span>generate-ecc option.<a class="copiable-link" href="#generate_002decc-option_002e"> &para;</a></span></h4>
<a class="anchor" id="p11tool-generate_002decc"></a>
<p>This is the &ldquo;generate an ecdsa private-public key pair&rdquo; option.
Generates an ECDSA private-public key pair on the specified token.
Should be combined with &ndash;curve, &ndash;sec-param or &ndash;bits.
</p>
<p><strong class="strong">NOTE</strong><strong class="strong">: THIS OPTION IS DEPRECATED</strong>
</p><h4 class="subsubheading" id="bits-option_002e"><span>bits option.<a class="copiable-link" href="#bits-option_002e"> &para;</a></span></h4>
<a class="anchor" id="p11tool-bits"></a>
<p>This is the &ldquo;specify the number of bits for the key generate&rdquo; option.
This option takes a ArgumentType.NUMBER argument.
For applications which have no key-size restrictions the
&ndash;sec-param option is recommended, as the sec-param levels will adapt
to the acceptable security levels with the new versions of gnutls.
</p><h4 class="subsubheading" id="curve-option_002e-1"><span>curve option.<a class="copiable-link" href="#curve-option_002e-1"> &para;</a></span></h4>
<a class="anchor" id="p11tool-curve"></a>
<p>This is the &ldquo;specify the curve used for ec key generation&rdquo; option.
This option takes a ArgumentType.STRING argument.
Supported values are secp192r1, secp224r1, secp256r1, secp384r1 and secp521r1.
</p><h4 class="subsubheading" id="sec_002dparam-option_002e-1"><span>sec-param option.<a class="copiable-link" href="#sec_002dparam-option_002e-1"> &para;</a></span></h4>
<a class="anchor" id="p11tool-sec_002dparam"></a>
<p>This is the &ldquo;specify the security level&rdquo; option.
This option takes a ArgumentType.STRING argument <samp class="file">Security parameter</samp>.
This is alternative to the bits option. Available options are [low, legacy, medium, high, ultra].
<a class="anchor" id="p11tool-write_002dobject_002drelated_002doptions"></a></p><h4 class="subsubheading" id="write_002dobject_002drelated_002doptions-options"><span>write-object-related-options options<a class="copiable-link" href="#write_002dobject_002drelated_002doptions-options"> &para;</a></span></h4>
<p>Writing objects.
</p><h4 class="subsubheading" id="set_002did-option_002e"><span>set-id option.<a class="copiable-link" href="#set_002did-option_002e"> &para;</a></span></h4>
<a class="anchor" id="p11tool-set_002did"></a>
<p>This is the &ldquo;set the cka_id (in hex) for the specified by the url object&rdquo; option.
This option takes a ArgumentType.STRING argument.
</p>
<p>This option has some usage constraints.  It:
</p><ul class="itemize mark-bullet">
<li>must not appear in combination with any of the following options:
write.
</li></ul>

<p>Modifies or sets the CKA_ID in the specified by the URL object. The ID should be specified in hexadecimal format without a &rsquo;0x&rsquo; prefix.
</p><h4 class="subsubheading" id="set_002dlabel-option_002e"><span>set-label option.<a class="copiable-link" href="#set_002dlabel-option_002e"> &para;</a></span></h4>
<a class="anchor" id="p11tool-set_002dlabel"></a>
<p>This is the &ldquo;set the cka_label for the specified by the url object&rdquo; option.
This option takes a ArgumentType.STRING argument.
</p>
<p>This option has some usage constraints.  It:
</p><ul class="itemize mark-bullet">
<li>must not appear in combination with any of the following options:
write, set-id.
</li></ul>

<p>Modifies or sets the CKA_LABEL in the specified by the URL object
</p><h4 class="subsubheading" id="write-option_002e"><span>write option.<a class="copiable-link" href="#write-option_002e"> &para;</a></span></h4>
<a class="anchor" id="p11tool-write"></a>
<p>This is the &ldquo;writes the loaded objects to a pkcs #11 token&rdquo; option.
It can be used to write private, public keys, certificates or secret keys to a token. Must be combined with one of &ndash;load-privkey, &ndash;load-pubkey, &ndash;load-certificate option.
</p>
<p>When writing a certificate object, its CKA_ID is set to the same CKA_ID of the corresponding public key, if it exists on the token; otherwise it will be derived from the X.509 Subject Key Identifier of the certificate. If this behavior is undesired, write the public key to the token beforehand.
</p><h4 class="subsubheading" id="id-option_002e"><span>id option.<a class="copiable-link" href="#id-option_002e"> &para;</a></span></h4>
<a class="anchor" id="p11tool-id"></a>
<p>This is the &ldquo;sets an id for the write operation&rdquo; option.
This option takes a ArgumentType.STRING argument.
Sets the CKA_ID to be set by the write operation. The ID should be specified in hexadecimal format without a &rsquo;0x&rsquo; prefix.
</p><h4 class="subsubheading" id="mark_002dwrap-option_002e"><span>mark-wrap option.<a class="copiable-link" href="#mark_002dwrap-option_002e"> &para;</a></span></h4>
<a class="anchor" id="p11tool-mark_002dwrap"></a>
<p>This is the &ldquo;marks the generated key to be a wrapping key&rdquo; option.
Marks the generated key with the CKA_WRAP flag.
</p><h4 class="subsubheading" id="mark_002dtrusted-option_002e"><span>mark-trusted option.<a class="copiable-link" href="#mark_002dtrusted-option_002e"> &para;</a></span></h4>
<a class="anchor" id="p11tool-mark_002dtrusted"></a>
<p>This is the &ldquo;marks the object to be written as trusted&rdquo; option.
</p>
<p>This option has some usage constraints.  It:
</p><ul class="itemize mark-bullet">
<li>must not appear in combination with any of the following options:
mark-distrusted.
</li><li>can be disabled with &ndash;no-mark-trusted.
</li></ul>

<p>Marks the object to be generated/written with the CKA_TRUST flag.
</p><h4 class="subsubheading" id="mark_002ddistrusted-option_002e"><span>mark-distrusted option.<a class="copiable-link" href="#mark_002ddistrusted-option_002e"> &para;</a></span></h4>
<a class="anchor" id="p11tool-mark_002ddistrusted"></a>
<p>This is the &ldquo;when retrieving objects, it requires the objects to be distrusted&rdquo; option.
</p>
<p>This option has some usage constraints.  It:
</p><ul class="itemize mark-bullet">
<li>must not appear in combination with any of the following options:
mark-trusted.
</li></ul>

<p>Ensures that the objects retrieved have the CKA_X_TRUST flag.
This is p11-kit trust module extension, thus this flag is only valid with
p11-kit registered trust modules.
</p><h4 class="subsubheading" id="mark_002ddecrypt-option_002e"><span>mark-decrypt option.<a class="copiable-link" href="#mark_002ddecrypt-option_002e"> &para;</a></span></h4>
<a class="anchor" id="p11tool-mark_002ddecrypt"></a>
<p>This is the &ldquo;marks the object to be written for decryption&rdquo; option.
Marks the object to be generated/written with the CKA_DECRYPT flag set to true.
</p><h4 class="subsubheading" id="mark_002dsign-option_002e"><span>mark-sign option.<a class="copiable-link" href="#mark_002dsign-option_002e"> &para;</a></span></h4>
<a class="anchor" id="p11tool-mark_002dsign"></a>
<p>This is the &ldquo;marks the object to be written for signature generation&rdquo; option.
Marks the object to be generated/written with the CKA_SIGN flag set to true.
</p><h4 class="subsubheading" id="mark_002dca-option_002e"><span>mark-ca option.<a class="copiable-link" href="#mark_002dca-option_002e"> &para;</a></span></h4>
<a class="anchor" id="p11tool-mark_002dca"></a>
<p>This is the &ldquo;marks the object to be written as a ca&rdquo; option.
Marks the object to be generated/written with the CKA_CERTIFICATE_CATEGORY as CA.
</p><h4 class="subsubheading" id="mark_002dprivate-option_002e"><span>mark-private option.<a class="copiable-link" href="#mark_002dprivate-option_002e"> &para;</a></span></h4>
<a class="anchor" id="p11tool-mark_002dprivate"></a>
<p>This is the &ldquo;marks the object to be written as private&rdquo; option.
Marks the object to be generated/written with the CKA_PRIVATE flag. The written object will require a PIN to be used.
</p><h4 class="subsubheading" id="ca-option_002e-1"><span>ca option.<a class="copiable-link" href="#ca-option_002e-1"> &para;</a></span></h4>
<a class="anchor" id="p11tool-ca"></a>
<p>This is an alias for the <code class="code">mark-ca</code> option,
see <a class="pxref" href="#p11tool-mark_002dca">the mark-ca option documentation</a>.
</p>
<h4 class="subsubheading" id="private-option_002e"><span>private option.<a class="copiable-link" href="#private-option_002e"> &para;</a></span></h4>
<a class="anchor" id="p11tool-private"></a>
<p>This is an alias for the <code class="code">mark-private</code> option,
see <a class="pxref" href="#p11tool-mark_002dprivate">the mark-private option documentation</a>.
</p>
<h4 class="subsubheading" id="mark_002dalways_002dauthenticate-option_002e"><span>mark-always-authenticate option.<a class="copiable-link" href="#mark_002dalways_002dauthenticate-option_002e"> &para;</a></span></h4>
<a class="anchor" id="p11tool-mark_002dalways_002dauthenticate"></a>
<p>This is the &ldquo;marks the object to be written as always authenticate&rdquo; option.
Marks the object to be generated/written with the CKA_ALWAYS_AUTHENTICATE flag. The written object will Mark the object as requiring authentication (pin entry) before every operation.
</p><h4 class="subsubheading" id="secret_002dkey-option_002e"><span>secret-key option.<a class="copiable-link" href="#secret_002dkey-option_002e"> &para;</a></span></h4>
<a class="anchor" id="p11tool-secret_002dkey"></a>
<p>This is the &ldquo;provide a hex encoded secret key&rdquo; option.
This option takes a ArgumentType.STRING argument.
This secret key will be written to the module if &ndash;write is specified.
<a class="anchor" id="p11tool-other_002doptions"></a></p><h4 class="subsubheading" id="other_002doptions-options-1"><span>other-options options<a class="copiable-link" href="#other_002doptions-options-1"> &para;</a></span></h4>
<p>Other options.
</p><h4 class="subsubheading" id="debug-option-_0028_002dd_0029_002e-8"><span>debug option (-d).<a class="copiable-link" href="#debug-option-_0028_002dd_0029_002e-8"> &para;</a></span></h4>
<a class="anchor" id="p11tool-debug"></a>
<p>This is the &ldquo;enable debugging&rdquo; option.
This option takes a ArgumentType.NUMBER argument.
Specifies the debug level.
</p><h4 class="subsubheading" id="so_002dlogin-option_002e"><span>so-login option.<a class="copiable-link" href="#so_002dlogin-option_002e"> &para;</a></span></h4>
<a class="anchor" id="p11tool-so_002dlogin"></a>
<p>This is the &ldquo;force security officer login to token&rdquo; option.
Forces login to the token as security officer (admin).
</p><h4 class="subsubheading" id="admin_002dlogin-option_002e"><span>admin-login option.<a class="copiable-link" href="#admin_002dlogin-option_002e"> &para;</a></span></h4>
<a class="anchor" id="p11tool-admin_002dlogin"></a>
<p>This is an alias for the <code class="code">so-login</code> option,
see <a class="pxref" href="#p11tool-so_002dlogin">the so-login option documentation</a>.
</p>
<h4 class="subsubheading" id="test_002dsign-option_002e"><span>test-sign option.<a class="copiable-link" href="#test_002dsign-option_002e"> &para;</a></span></h4>
<a class="anchor" id="p11tool-test_002dsign"></a>
<p>This is the &ldquo;tests the signature operation of the provided object&rdquo; option.
It can be used to test the correct operation of the signature operation.
If both a private and a public key are available this operation will sign and verify
the signed data.
</p><h4 class="subsubheading" id="sign_002dparams-option_002e-1"><span>sign-params option.<a class="copiable-link" href="#sign_002dparams-option_002e-1"> &para;</a></span></h4>
<a class="anchor" id="p11tool-sign_002dparams"></a>
<p>This is the &ldquo;sign with a specific signature algorithm&rdquo; option.
This option takes a ArgumentType.STRING argument.
This option can be combined with &ndash;test-sign, to sign with
a specific signature algorithm variant. The only option supported is &rsquo;RSA-PSS&rsquo;, and should be
specified in order to use RSA-PSS signature on RSA keys.
</p><h4 class="subsubheading" id="hash-option_002e-2"><span>hash option.<a class="copiable-link" href="#hash-option_002e-2"> &para;</a></span></h4>
<a class="anchor" id="p11tool-hash"></a>
<p>This is the &ldquo;hash algorithm to use for signing&rdquo; option.
This option takes a ArgumentType.STRING argument.
This option can be combined with test-sign. Available hash functions are SHA1, RMD160, SHA256, SHA384, SHA512, SHA3-224, SHA3-256, SHA3-384, SHA3-512.
</p><h4 class="subsubheading" id="generate_002drandom-option_002e"><span>generate-random option.<a class="copiable-link" href="#generate_002drandom-option_002e"> &para;</a></span></h4>
<a class="anchor" id="p11tool-generate_002drandom"></a>
<p>This is the &ldquo;generate random data&rdquo; option.
This option takes a ArgumentType.NUMBER argument.
Asks the token to generate a number of bytes of random bytes.
</p><h4 class="subsubheading" id="inder-option_002e-2"><span>inder option.<a class="copiable-link" href="#inder-option_002e-2"> &para;</a></span></h4>
<a class="anchor" id="p11tool-inder"></a>
<p>This is the &ldquo;use der/raw format for input&rdquo; option.
Use DER/RAW format for input certificates and private keys.
</p><h4 class="subsubheading" id="inraw-option_002e-2"><span>inraw option.<a class="copiable-link" href="#inraw-option_002e-2"> &para;</a></span></h4>
<a class="anchor" id="p11tool-inraw"></a>
<p>This is an alias for the <code class="code">inder</code> option,
see <a class="pxref" href="#p11tool-inder">the inder option documentation</a>.
</p>
<h4 class="subsubheading" id="outder-option_002e-2"><span>outder option.<a class="copiable-link" href="#outder-option_002e-2"> &para;</a></span></h4>
<a class="anchor" id="p11tool-outder"></a>
<p>This is the &ldquo;use der format for output certificates, private keys, and dh parameters&rdquo; option.
The output will be in DER or RAW format.
</p><h4 class="subsubheading" id="outraw-option_002e-1"><span>outraw option.<a class="copiable-link" href="#outraw-option_002e-1"> &para;</a></span></h4>
<a class="anchor" id="p11tool-outraw"></a>
<p>This is an alias for the <code class="code">outder</code> option,
see <a class="pxref" href="#p11tool-outder">the outder option documentation</a>.
</p>
<h4 class="subsubheading" id="provider-option_002e-3"><span>provider option.<a class="copiable-link" href="#provider-option_002e-3"> &para;</a></span></h4>
<a class="anchor" id="p11tool-provider"></a>
<p>This is the &ldquo;specify the pkcs #11 provider library&rdquo; option.
This option takes a ArgumentType.FILE argument.
This will override the default options in /etc/gnutls/pkcs11.conf
</p><h4 class="subsubheading" id="provider_002dopts-option_002e"><span>provider-opts option.<a class="copiable-link" href="#provider_002dopts-option_002e"> &para;</a></span></h4>
<a class="anchor" id="p11tool-provider_002dopts"></a>
<p>This is the &ldquo;specify parameters for the pkcs #11 provider library&rdquo; option.
This option takes a ArgumentType.STRING argument.
This is a PKCS#11 internal option used by few modules.
    Mainly for testing PKCS#11 modules.
</p>
<p><strong class="strong">NOTE</strong><strong class="strong">: THIS OPTION IS DEPRECATED</strong>
</p><h4 class="subsubheading" id="batch-option_002e"><span>batch option.<a class="copiable-link" href="#batch-option_002e"> &para;</a></span></h4>
<a class="anchor" id="p11tool-batch"></a>
<p>This is the &ldquo;disable all interaction with the tool&rdquo; option.
In batch mode there will be no prompts, all parameters need to be specified on command line.
</p><h4 class="subsubheading" id="version-option-_0028_002dv_0029_002e-8"><span>version option (-v).<a class="copiable-link" href="#version-option-_0028_002dv_0029_002e-8"> &para;</a></span></h4>
<a class="anchor" id="p11tool-version"></a>
<p>This is the &ldquo;output version information and exit&rdquo; option.
This option takes a ArgumentType.KEYWORD argument.
Output version of program and exit.  The default mode is &lsquo;v&rsquo;, a simple
version.  The &lsquo;c&rsquo; mode will print copyright information and &lsquo;n&rsquo; will
print the full copyright notice.
</p><h4 class="subsubheading" id="help-option-_0028_002dh_0029_002e-8"><span>help option (-h).<a class="copiable-link" href="#help-option-_0028_002dh_0029_002e-8"> &para;</a></span></h4>
<a class="anchor" id="p11tool-help"></a>
<p>This is the &ldquo;display extended usage information and exit&rdquo; option.
Display usage information and exit.
</p><h4 class="subsubheading" id="more_002dhelp-option-_0028_002d_0021_0029_002e-8"><span>more-help option (-!).<a class="copiable-link" href="#more_002dhelp-option-_0028_002d_0021_0029_002e-8"> &para;</a></span></h4>
<a class="anchor" id="p11tool-more_002dhelp"></a>
<p>This is the &ldquo;extended usage information passed thru pager&rdquo; option.
Pass the extended usage information through a pager.
<a class="anchor" id="p11tool-exit-status"></a></p><h4 class="subsubheading" id="p11tool-exit-status-1"><span>p11tool exit status<a class="copiable-link" href="#p11tool-exit-status-1"> &para;</a></span></h4>

<p>One of the following exit values will be returned:
</p><dl class="table">
<dt>&lsquo;<samp class="samp">0 (EXIT_SUCCESS)</samp>&rsquo;</dt>
<dd><p>Successful program execution.
</p></dd>
<dt>&lsquo;<samp class="samp">1 (EXIT_FAILURE)</samp>&rsquo;</dt>
<dd><p>The operation failed or the command syntax was not valid.
</p></dd>
</dl>
<a class="anchor" id="p11tool-See-Also"></a><h4 class="subsubheading" id="p11tool-See-Also-1"><span>p11tool See Also<a class="copiable-link" href="#p11tool-See-Also-1"> &para;</a></span></h4>
<p>certtool (1)
<a class="anchor" id="p11tool-Examples"></a></p><h4 class="subsubheading" id="p11tool-Examples-1"><span>p11tool Examples<a class="copiable-link" href="#p11tool-Examples-1"> &para;</a></span></h4>
<p>To view all tokens in your system use:
</p><div class="example">
<pre class="example-preformatted">$ p11tool --list-tokens
</pre></div>

<p>To view all objects in a token use:
</p><div class="example">
<pre class="example-preformatted">$ p11tool --login --list-all &quot;pkcs11:TOKEN-URL&quot;
</pre></div>

<p>To store a private key and a certificate in a token run:
</p><div class="example">
<pre class="example-preformatted">$ p11tool --login --write &quot;pkcs11:URL&quot; --load-privkey key.pem \
          --label &quot;Mykey&quot;
$ p11tool --login --write &quot;pkcs11:URL&quot; --load-certificate cert.pem \
          --label &quot;Mykey&quot;
</pre></div>
<p>Note that some tokens require the same label to be used for the certificate
and its corresponding private key.
</p>
<p>To generate an RSA private key inside the token use:
</p><div class="example">
<pre class="example-preformatted">$ p11tool --login --generate-privkey rsa --bits 1024 --label &quot;MyNewKey&quot; \
          --outfile MyNewKey.pub &quot;pkcs11:TOKEN-URL&quot;
</pre></div>
<p>The bits parameter in the above example is explicitly set because some
tokens only support limited choices in the bit length. The output file is the
corresponding public key. This key can be used to general a certificate
request with certtool.
</p><div class="example">
<pre class="example-preformatted">certtool --generate-request --load-privkey &quot;pkcs11:KEY-URL&quot; \
   --load-pubkey MyNewKey.pub --outfile request.pem
</pre></div>


<hr>
</div>
</div>
<div class="section-level-extent" id="Trusted-Platform-Module">
<div class="nav-panel">
<p>
Previous: <a href="#Smart-cards-and-HSMs" accesskey="p" rel="prev">Smart cards and HSMs</a>, Up: <a href="#Hardware-security-modules-and-abstract-key-types" accesskey="u" rel="up">Abstract key types and Hardware security modules</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Trusted-Platform-Module-_0028TPM_0029"><span>5.4 Trusted Platform Module (TPM)<a class="copiable-link" href="#Trusted-Platform-Module-_0028TPM_0029"> &para;</a></span></h3>
<a class="index-entry-id" id="index-trusted-platform-module"></a>
<a class="index-entry-id" id="index-TPM"></a>

<p>In this section we present the Trusted Platform Module (TPM) support 
in <abbr class="acronym">GnuTLS</abbr>. Note that we recommend against using TPM with this
API because it is restricted to TPM 1.2. We recommend instead
to use PKCS#11 wrappers for TPM such as CHAPS<a class="footnote" id="DOCF14" href="#FOOT14"><sup>14</sup></a> or opencryptoki<a class="footnote" id="DOCF15" href="#FOOT15"><sup>15</sup></a>.
These will allow using the standard smart card and HSM functionality (see <a class="ref" href="#Smart-cards-and-HSMs">Smart cards and HSMs</a>) for TPM keys.
</p>
<p>There was a big hype when the TPM chip was introduced into 
computers. Briefly it is a co-processor in your PC that allows it to perform 
calculations independently of the main processor. This has good and bad 
side-effects. In this section we focus on the good ones; these are the fact that 
you can use the TPM chip to perform cryptographic operations on keys stored in it, without 
accessing them. That is very similar to the operation of a <abbr class="acronym">PKCS</abbr> #11 smart card. 
The chip allows for storage and usage of RSA keys, but has quite some 
operational differences from <abbr class="acronym">PKCS</abbr> #11 module, and thus require different handling. 
The basic TPM operations supported and used by GnuTLS, are key generation and signing. 
That support is currently limited to TPM 1.2.
</p>
<p>The next sections assume that the TPM chip in the system is already initialized and
in a operational state. If not, ensure that the TPM chip is enabled by your BIOS,
that the <code class="code">tcsd</code> daemon is running, and that TPM ownership is set
(by running <code class="code">tpm_takeownership</code>).
</p>
<p>In GnuTLS the TPM functionality is available in <code class="code">gnutls/tpm.h</code>.
</p>

<ul class="mini-toc">
<li><a href="#Keys-in-TPM" accesskey="1">Keys in TPM</a></li>
<li><a href="#Key-generation" accesskey="2">Key generation</a></li>
<li><a href="#Using-keys" accesskey="3">Using keys</a></li>
<li><a href="#tpmtool-Invocation" accesskey="4">Invoking tpmtool</a></li>
</ul>
<hr>
<div class="subsection-level-extent" id="Keys-in-TPM">
<div class="nav-panel">
<p>
Next: <a href="#Key-generation" accesskey="n" rel="next">Key generation</a>, Up: <a href="#Trusted-Platform-Module" accesskey="u" rel="up">Trusted Platform Module (TPM)</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Keys-in-TPM-1"><span>5.4.1 Keys in TPM<a class="copiable-link" href="#Keys-in-TPM-1"> &para;</a></span></h4>

<p>The RSA keys in the TPM module may either be stored in a flash memory
within TPM or stored in a file in disk. In the former case the key can
provide operations as with <abbr class="acronym">PKCS</abbr> #11 and is identified by
a URL. The URL is described in [<a class="ref" href="#TPMURI">TPMURI</a>] and is of the following form.
</p><pre class="verbatim">tpmkey:uuid=42309df8-d101-11e1-a89a-97bb33c23ad1;storage=user
</pre>
<p>It consists from a unique identifier of the key as well as the part of the
flash memory the key is stored at. The two options for the storage field are
&lsquo;user&rsquo; and &lsquo;system&rsquo;. The user keys are typically only available to the generating
user and the system keys to all users. The stored in TPM keys are called
registered keys.
</p>
<p>The keys that are stored in the disk are exported from the TPM but in an
encrypted form. To access them two passwords are required. The first is the TPM
Storage Root Key (SRK), and the other is a key-specific password. Also those keys are
identified by a URL of the form:
</p><pre class="verbatim">tpmkey:file=/path/to/file
</pre>
<p>When objects require a PIN to be accessed the same callbacks as with PKCS #11
objects are expected (see <a class="ref" href="#Accessing-objects-that-require-a-PIN">Accessing objects that require a PIN</a>). Note
that the PIN function may be called multiple times to unlock the SRK and
the specific key in use. The label in the key function will then be set to
&lsquo;SRK&rsquo; when unlocking the SRK key, or to &lsquo;TPM&rsquo; when unlocking any other key.
</p>
<hr>
</div>
<div class="subsection-level-extent" id="Key-generation">
<div class="nav-panel">
<p>
Next: <a href="#Using-keys" accesskey="n" rel="next">Using keys</a>, Previous: <a href="#Keys-in-TPM" accesskey="p" rel="prev">Keys in TPM</a>, Up: <a href="#Trusted-Platform-Module" accesskey="u" rel="up">Trusted Platform Module (TPM)</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Key-generation-1"><span>5.4.2 Key generation<a class="copiable-link" href="#Key-generation-1"> &para;</a></span></h4>

<p>All keys used by the TPM must be generated by the TPM. This can be
done using <a class="ref" href="#gnutls_005ftpm_005fprivkey_005fgenerate">gnutls_tpm_privkey_generate</a>.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ftpm_005fprivkey_005fgenerate"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_tpm_privkey_generate</strong> <code class="def-code-arguments">(gnutls_pk_algorithm_t <var class="var">pk</var>, unsigned int <var class="var">bits</var>, const char * <var class="var">srk_password</var>, const char * <var class="var">key_password</var>, gnutls_tpmkey_fmt_t <var class="var">format</var>, gnutls_x509_crt_fmt_t <var class="var">pub_format</var>, gnutls_datum_t * <var class="var">privkey</var>, gnutls_datum_t * <var class="var">pubkey</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005ftpm_005fprivkey_005fgenerate"> &para;</a></span></dt>
<dd><p><var class="var">pk</var>: the public key algorithm
</p>
<p><var class="var">bits</var>: the security bits
</p>
<p><var class="var">srk_password</var>: a password to protect the exported key (optional)
</p>
<p><var class="var">key_password</var>: the password for the TPM (optional)
</p>
<p><var class="var">format</var>: the format of the private key
</p>
<p><var class="var">pub_format</var>: the format of the public key
</p>
<p><var class="var">privkey</var>: the generated key
</p>
<p><var class="var">pubkey</var>: the corresponding public key (may be null)
</p>
<p><var class="var">flags</var>: should be a list of GNUTLS_TPM_* flags
</p>
<p>This function will generate a private key in the TPM
chip. The private key will be generated within the chip
and will be exported in a wrapped with TPM&rsquo;s master key
form. Furthermore the wrapped key can be protected with
the provided  <code class="code">password</code> .
</p>
<p>Note that bits in TPM is quantized value. If the input value
is not one of the allowed values, then it will be quantized to
one of 512, 1024, 2048, 4096, 8192 and 16384.
</p>
<p>Allowed flags are:
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.1.0
</p></dd></dl>

<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005ftpm_005fget_005fregistered">gnutls_tpm_get_registered</a> (gnutls_tpm_key_list_t * <var class="var">list</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005ftpm_005fkey_005flist_005fdeinit">gnutls_tpm_key_list_deinit</a> (gnutls_tpm_key_list_t <var class="var">list</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005ftpm_005fkey_005flist_005fget_005furl">gnutls_tpm_key_list_get_url</a> (gnutls_tpm_key_list_t <var class="var">list</var>, unsigned int <var class="var">idx</var>, char ** <var class="var">url</var>, unsigned int <var class="var">flags</var>)</code></dt>
</dl>





<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ftpm_005fprivkey_005fdelete"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_tpm_privkey_delete</strong> <code class="def-code-arguments">(const char * <var class="var">url</var>, const char * <var class="var">srk_password</var>)</code><a class="copiable-link" href="#index-gnutls_005ftpm_005fprivkey_005fdelete"> &para;</a></span></dt>
<dd><p><var class="var">url</var>: the URL describing the key
</p>
<p><var class="var">srk_password</var>: a password for the SRK key
</p>
<p>This function will unregister the private key from the TPM
chip. 
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.1.0
</p></dd></dl>

<hr>
</div>
<div class="subsection-level-extent" id="Using-keys">
<div class="nav-panel">
<p>
Next: <a href="#tpmtool-Invocation" accesskey="n" rel="next">Invoking tpmtool</a>, Previous: <a href="#Key-generation" accesskey="p" rel="prev">Key generation</a>, Up: <a href="#Trusted-Platform-Module" accesskey="u" rel="up">Trusted Platform Module (TPM)</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Using-keys-1"><span>5.4.3 Using keys<a class="copiable-link" href="#Using-keys-1"> &para;</a></span></h4>

<h4 class="subsubheading" id="Importing-keys"><span>Importing keys<a class="copiable-link" href="#Importing-keys"> &para;</a></span></h4>

<p>The TPM keys can be used directly by the abstract key types and do not require
any special structures. Moreover functions like <a class="ref" href="#gnutls_005fcertificate_005fset_005fx509_005fkey_005ffile2">gnutls_certificate_set_x509_key_file2</a>
can access TPM URLs.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fprivkey_005fimport_005ftpm_005fraw">gnutls_privkey_import_tpm_raw</a> (gnutls_privkey_t <var class="var">pkey</var>, const gnutls_datum_t * <var class="var">fdata</var>, gnutls_tpmkey_fmt_t <var class="var">format</var>, const char * <var class="var">srk_password</var>, const char * <var class="var">key_password</var>, unsigned int <var class="var">flags</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpubkey_005fimport_005ftpm_005fraw">gnutls_pubkey_import_tpm_raw</a> (gnutls_pubkey_t <var class="var">pkey</var>, const gnutls_datum_t * <var class="var">fdata</var>, gnutls_tpmkey_fmt_t <var class="var">format</var>, const char * <var class="var">srk_password</var>, unsigned int <var class="var">flags</var>)</code></dt>
</dl>





<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fimport_005ftpm_005furl"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_import_tpm_url</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">pkey</var>, const char * <var class="var">url</var>, const char * <var class="var">srk_password</var>, const char * <var class="var">key_password</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fimport_005ftpm_005furl"> &para;</a></span></dt>
<dd><p><var class="var">pkey</var>: The private key
</p>
<p><var class="var">url</var>: The URL of the TPM key to be imported
</p>
<p><var class="var">srk_password</var>: The password for the SRK key (optional)
</p>
<p><var class="var">key_password</var>: A password for the key (optional)
</p>
<p><var class="var">flags</var>: One of the GNUTLS_PRIVKEY_* flags
</p>
<p>This function will import the given private key to the abstract
<code class="code">gnutls_privkey_t</code>  type.
</p>
<p>Note that unless <code class="code">GNUTLS_PRIVKEY_DISABLE_CALLBACKS</code> 
is specified, if incorrect (or NULL) passwords are given
the PKCS11 callback functions will be used to obtain the
correct passwords. Otherwise if the SRK password is wrong
<code class="code">GNUTLS_E_TPM_SRK_PASSWORD_ERROR</code>  is returned and if the key password
is wrong or not provided then <code class="code">GNUTLS_E_TPM_KEY_PASSWORD_ERROR</code> 
is returned. 
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.1.0
</p></dd></dl>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fimport_005ftpm_005furl"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_import_tpm_url</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">pkey</var>, const char * <var class="var">url</var>, const char * <var class="var">srk_password</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fimport_005ftpm_005furl"> &para;</a></span></dt>
<dd><p><var class="var">pkey</var>: The public key
</p>
<p><var class="var">url</var>: The URL of the TPM key to be imported
</p>
<p><var class="var">srk_password</var>: The password for the SRK key (optional)
</p>
<p><var class="var">flags</var>: should be zero
</p>
<p>This function will import the given private key to the abstract
<code class="code">gnutls_privkey_t</code>  type. 
</p>
<p>Note that unless <code class="code">GNUTLS_PUBKEY_DISABLE_CALLBACKS</code> 
is specified, if incorrect (or NULL) passwords are given
the PKCS11 callback functions will be used to obtain the
correct passwords. Otherwise if the SRK password is wrong
<code class="code">GNUTLS_E_TPM_SRK_PASSWORD_ERROR</code>  is returned.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.1.0
</p></dd></dl>

<h4 class="subsubheading" id="Listing-and-deleting-keys"><span>Listing and deleting keys<a class="copiable-link" href="#Listing-and-deleting-keys"> &para;</a></span></h4>

<p>The registered keys (that are stored in the TPM) can be listed using one of
the following functions. Those keys are unfortunately only identified by
their UUID and have no label or other human friendly identifier.
Keys can be deleted from permanent storage using <a class="ref" href="#gnutls_005ftpm_005fprivkey_005fdelete">gnutls_tpm_privkey_delete</a>.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005ftpm_005fget_005fregistered">gnutls_tpm_get_registered</a> (gnutls_tpm_key_list_t * <var class="var">list</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005ftpm_005fkey_005flist_005fdeinit">gnutls_tpm_key_list_deinit</a> (gnutls_tpm_key_list_t <var class="var">list</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005ftpm_005fkey_005flist_005fget_005furl">gnutls_tpm_key_list_get_url</a> (gnutls_tpm_key_list_t <var class="var">list</var>, unsigned int <var class="var">idx</var>, char ** <var class="var">url</var>, unsigned int <var class="var">flags</var>)</code></dt>
</dl>





<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ftpm_005fprivkey_005fdelete-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_tpm_privkey_delete</strong> <code class="def-code-arguments">(const char * <var class="var">url</var>, const char * <var class="var">srk_password</var>)</code><a class="copiable-link" href="#index-gnutls_005ftpm_005fprivkey_005fdelete-1"> &para;</a></span></dt>
<dd><p><var class="var">url</var>: the URL describing the key
</p>
<p><var class="var">srk_password</var>: a password for the SRK key
</p>
<p>This function will unregister the private key from the TPM
chip. 
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.1.0
</p></dd></dl>


<hr>
</div>
<div class="subsection-level-extent" id="tpmtool-Invocation">
<div class="nav-panel">
<p>
Previous: <a href="#Using-keys" accesskey="p" rel="prev">Using keys</a>, Up: <a href="#Trusted-Platform-Module" accesskey="u" rel="up">Trusted Platform Module (TPM)</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Invoking-tpmtool"><span>5.4.4 Invoking tpmtool<a class="copiable-link" href="#Invoking-tpmtool"> &para;</a></span></h4>
<a class="index-entry-id" id="index-tpmtool"></a>

<p>Program that allows handling cryptographic data from the TPM chip.
</p>
<a class="anchor" id="tpmtool-usage"></a><h4 class="subsubheading" id="tpmtool-help_002fusage-_0028_002d_003f_0029"><span>tpmtool help/usage (<samp class="option">-?</samp>)<a class="copiable-link" href="#tpmtool-help_002fusage-_0028_002d_003f_0029"> &para;</a></span></h4>
<a class="index-entry-id" id="index-tpmtool-help"></a>

<p>The text printed is the same whether selected with the <code class="code">help</code> option
(<samp class="option">--help</samp>) or the <code class="code">more-help</code> option (<samp class="option">--more-help</samp>).  <code class="code">more-help</code> will print
the usage text by passing it through a pager program.
<code class="code">more-help</code> is disabled on platforms without a working
<code class="code">fork(2)</code> function.  The <code class="code">PAGER</code> environment variable is
used to select the program, defaulting to <samp class="file">more</samp>.  Both will exit
with a status code of 0.
</p>
<div class="example">
<pre class="example-preformatted">tpmtool - GnuTLS TPM tool
Usage:  tpmtool [ -&lt;flag&gt; [&lt;val&gt;] | --&lt;name&gt;[{=| }&lt;val&gt;] ]... 

None:

   -d, --debug=num            Enable debugging
				- it must be in the range:
				  0 to 9999
       --infile=file          Input file
				- file must pre-exist
       --outfile=str          Output file
       --generate-rsa         Generate an RSA private-public key pair
       --register             Any generated key will be registered in the TPM
				- requires the option 'generate-rsa'
       --signing              Any generated key will be a signing key
				- prohibits the option 'legacy'
				- requires the option 'generate-rsa'
       --legacy               Any generated key will be a legacy key
				- prohibits the option 'signing'
				- requires the option 'generate-rsa'
       --user                 Any registered key will be a user key
				- prohibits the option 'system'
				- requires the option 'register'
       --system               Any registered key will be a system key
				- prohibits the option 'user'
				- requires the option 'register'
       --pubkey=str           Prints the public key of the provided key
       --list                 Lists all stored keys in the TPM
       --delete=str           Delete the key identified by the given URL (UUID)
       --test-sign=str        Tests the signature operation of the provided object
       --sec-param=str        Specify the security level [low, legacy, medium, high, ultra]
       --bits=num             Specify the number of bits for key generate
       --inder                Use the DER format for keys
       --outder               Use DER format for output keys
       --srk-well-known       SRK has well known password (20 bytes of zeros)

Version, usage and configuration options:

   -v, --version[=arg]        output version information and exit
   -h, --help                 display extended usage information and exit
   -!, --more-help            extended usage information passed thru pager

Options are specified by doubled hyphens and their name or by a single
hyphen and the flag character.

Program that allows handling cryptographic data from the TPM chip.

Please send bug reports to:  &lt;bugs@gnutls.org&gt;

</pre></div>

<h4 class="subsubheading" id="debug-option-_0028_002dd_0029_002e-9"><span>debug option (-d).<a class="copiable-link" href="#debug-option-_0028_002dd_0029_002e-9"> &para;</a></span></h4>
<a class="anchor" id="tpmtool-debug"></a>
<p>This is the &ldquo;enable debugging&rdquo; option.
This option takes a ArgumentType.NUMBER argument.
Specifies the debug level.
</p><h4 class="subsubheading" id="generate_002drsa-option_002e-1"><span>generate-rsa option.<a class="copiable-link" href="#generate_002drsa-option_002e-1"> &para;</a></span></h4>
<a class="anchor" id="tpmtool-generate_002drsa"></a>
<p>This is the &ldquo;generate an rsa private-public key pair&rdquo; option.
Generates an RSA private-public key pair in the TPM chip. 
The key may be stored in file system and protected by a PIN, or stored (registered)
in the TPM chip flash.
</p><h4 class="subsubheading" id="user-option_002e"><span>user option.<a class="copiable-link" href="#user-option_002e"> &para;</a></span></h4>
<a class="anchor" id="tpmtool-user"></a>
<p>This is the &ldquo;any registered key will be a user key&rdquo; option.
</p>
<p>This option has some usage constraints.  It:
</p><ul class="itemize mark-bullet">
<li>must not appear in combination with any of the following options:
system.
</li><li>must appear in combination with the following options:
register.
</li></ul>

<p>The generated key will be stored in a user specific persistent storage.
</p><h4 class="subsubheading" id="system-option_002e"><span>system option.<a class="copiable-link" href="#system-option_002e"> &para;</a></span></h4>
<a class="anchor" id="tpmtool-system"></a>
<p>This is the &ldquo;any registered key will be a system key&rdquo; option.
</p>
<p>This option has some usage constraints.  It:
</p><ul class="itemize mark-bullet">
<li>must not appear in combination with any of the following options:
user.
</li><li>must appear in combination with the following options:
register.
</li></ul>

<p>The generated key will be stored in system persistent storage.
</p><h4 class="subsubheading" id="test_002dsign-option_002e-1"><span>test-sign option.<a class="copiable-link" href="#test_002dsign-option_002e-1"> &para;</a></span></h4>
<a class="anchor" id="tpmtool-test_002dsign"></a>
<p>This is the &ldquo;tests the signature operation of the provided object&rdquo; option.
This option takes a ArgumentType.STRING argument <samp class="file">url</samp>.
It can be used to test the correct operation of the signature operation.
This operation will sign and verify the signed data.
</p><h4 class="subsubheading" id="sec_002dparam-option_002e-2"><span>sec-param option.<a class="copiable-link" href="#sec_002dparam-option_002e-2"> &para;</a></span></h4>
<a class="anchor" id="tpmtool-sec_002dparam"></a>
<p>This is the &ldquo;specify the security level [low, legacy, medium, high, ultra]&rdquo; option.
This option takes a ArgumentType.STRING argument <samp class="file">Security parameter</samp>.
This is alternative to the bits option. Note however that the
values allowed by the TPM chip are quantized and given values may be rounded up.
</p><h4 class="subsubheading" id="inder-option_002e-3"><span>inder option.<a class="copiable-link" href="#inder-option_002e-3"> &para;</a></span></h4>
<a class="anchor" id="tpmtool-inder"></a>
<p>This is the &ldquo;use the der format for keys&rdquo; option.
The input files will be assumed to be in the portable
DER format of TPM. The default format is a custom format used by various
TPM tools
</p><h4 class="subsubheading" id="outder-option_002e-3"><span>outder option.<a class="copiable-link" href="#outder-option_002e-3"> &para;</a></span></h4>
<a class="anchor" id="tpmtool-outder"></a>
<p>This is the &ldquo;use der format for output keys&rdquo; option.
The output will be in the TPM portable DER format.
</p><h4 class="subsubheading" id="version-option-_0028_002dv_0029_002e-9"><span>version option (-v).<a class="copiable-link" href="#version-option-_0028_002dv_0029_002e-9"> &para;</a></span></h4>
<a class="anchor" id="tpmtool-version"></a>
<p>This is the &ldquo;output version information and exit&rdquo; option.
This option takes a ArgumentType.KEYWORD argument.
Output version of program and exit.  The default mode is &lsquo;v&rsquo;, a simple
version.  The &lsquo;c&rsquo; mode will print copyright information and &lsquo;n&rsquo; will
print the full copyright notice.
</p><h4 class="subsubheading" id="help-option-_0028_002dh_0029_002e-9"><span>help option (-h).<a class="copiable-link" href="#help-option-_0028_002dh_0029_002e-9"> &para;</a></span></h4>
<a class="anchor" id="tpmtool-help"></a>
<p>This is the &ldquo;display extended usage information and exit&rdquo; option.
Display usage information and exit.
</p><h4 class="subsubheading" id="more_002dhelp-option-_0028_002d_0021_0029_002e-9"><span>more-help option (-!).<a class="copiable-link" href="#more_002dhelp-option-_0028_002d_0021_0029_002e-9"> &para;</a></span></h4>
<a class="anchor" id="tpmtool-more_002dhelp"></a>
<p>This is the &ldquo;extended usage information passed thru pager&rdquo; option.
Pass the extended usage information through a pager.
<a class="anchor" id="tpmtool-exit-status"></a></p><h4 class="subsubheading" id="tpmtool-exit-status-1"><span>tpmtool exit status<a class="copiable-link" href="#tpmtool-exit-status-1"> &para;</a></span></h4>

<p>One of the following exit values will be returned:
</p><dl class="table">
<dt>&lsquo;<samp class="samp">0 (EXIT_SUCCESS)</samp>&rsquo;</dt>
<dd><p>Successful program execution.
</p></dd>
<dt>&lsquo;<samp class="samp">1 (EXIT_FAILURE)</samp>&rsquo;</dt>
<dd><p>The operation failed or the command syntax was not valid.
</p></dd>
</dl>
<a class="anchor" id="tpmtool-See-Also"></a><h4 class="subsubheading" id="tpmtool-See-Also-1"><span>tpmtool See Also<a class="copiable-link" href="#tpmtool-See-Also-1"> &para;</a></span></h4>
<p>p11tool (1), certtool (1)
<a class="anchor" id="tpmtool-Examples"></a></p><h4 class="subsubheading" id="tpmtool-Examples-1"><span>tpmtool Examples<a class="copiable-link" href="#tpmtool-Examples-1"> &para;</a></span></h4>
<p>To generate a key that is to be stored in file system use:
</p><div class="example">
<pre class="example-preformatted">$ tpmtool --generate-rsa --bits 2048 --outfile tpmkey.pem
</pre></div>

<p>To generate a key that is to be stored in TPM&rsquo;s flash use:
</p><div class="example">
<pre class="example-preformatted">$ tpmtool --generate-rsa --bits 2048 --register --user
</pre></div>

<p>To get the public key of a TPM key use:
</p><div class="example">
<pre class="example-preformatted">$ tpmtool --pubkey tpmkey:uuid=58ad734b-bde6-45c7-89d8-756a55ad1891;storage=user \
          --outfile pubkey.pem
</pre></div>

<p>or if the key is stored in the file system:
</p><div class="example">
<pre class="example-preformatted">$ tpmtool --pubkey tpmkey:file=tmpkey.pem --outfile pubkey.pem
</pre></div>

<p>To list all keys stored in TPM use:
</p><div class="example">
<pre class="example-preformatted">$ tpmtool --list
</pre></div>


<hr>
</div>
</div>
</div>
<div class="chapter-level-extent" id="How-to-use-GnuTLS-in-applications">
<div class="nav-panel">
<p>
Next: <a href="#GnuTLS-application-examples" accesskey="n" rel="next">GnuTLS application examples</a>, Previous: <a href="#Hardware-security-modules-and-abstract-key-types" accesskey="p" rel="prev">Abstract key types and Hardware security modules</a>, Up: <a href="#Top" accesskey="u" rel="up">GnuTLS</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h2 class="chapter" id="How-to-use-GnuTLS-in-applications-1"><span>6 How to use <abbr class="acronym">GnuTLS</abbr> in applications<a class="copiable-link" href="#How-to-use-GnuTLS-in-applications-1"> &para;</a></span></h2>


<ul class="mini-toc">
<li><a href="#Introduction-to-the-library" accesskey="1">Introduction</a></li>
<li><a href="#Preparation" accesskey="2">Preparation</a></li>
<li><a href="#Session-initialization" accesskey="3">Session initialization</a></li>
<li><a href="#Associating-the-credentials" accesskey="4">Associating the credentials</a></li>
<li><a href="#Setting-up-the-transport-layer" accesskey="5">Setting up the transport layer</a></li>
<li><a href="#TLS-handshake" accesskey="6">TLS handshake</a></li>
<li><a href="#Data-transfer-and-termination" accesskey="7">Data transfer and termination</a></li>
<li><a href="#Buffered-data-transfer" accesskey="8">Buffered data transfer</a></li>
<li><a href="#Handling-alerts" accesskey="9">Handling alerts</a></li>
<li><a href="#Priority-Strings">Priority strings</a></li>
<li><a href="#Selecting-cryptographic-key-sizes">Selecting cryptographic key sizes</a></li>
<li><a href="#Advanced-topics">Advanced topics</a></li>
</ul>
<hr>
<div class="section-level-extent" id="Introduction-to-the-library">
<div class="nav-panel">
<p>
Next: <a href="#Preparation" accesskey="n" rel="next">Preparation</a>, Up: <a href="#How-to-use-GnuTLS-in-applications" accesskey="u" rel="up">How to use <abbr class="acronym">GnuTLS</abbr> in applications</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Introduction"><span>6.1 Introduction<a class="copiable-link" href="#Introduction"> &para;</a></span></h3>

<p>This chapter tries to explain the basic functionality of the current GnuTLS
library. Note that there may be additional functionality not discussed here
but included in the library. Checking the header files in <samp class="file">/usr/include/gnutls/</samp>
and the manpages is recommended.
</p>

<ul class="mini-toc">
<li><a href="#General-idea" accesskey="1">General idea</a></li>
<li><a href="#Error-handling" accesskey="2">Error handling</a></li>
<li><a href="#Common-types" accesskey="3">Common types</a></li>
<li><a href="#Debugging-and-auditing" accesskey="4">Debugging and auditing</a></li>
<li><a href="#Thread-safety" accesskey="5">Thread safety</a></li>
<li><a href="#Running-in-a-sandbox" accesskey="6">Running in a sandbox</a></li>
<li><a href="#Sessions-and-fork" accesskey="7">Sessions and fork</a></li>
<li><a href="#Callback-functions" accesskey="8">Callback functions</a></li>
</ul>
<hr>
<div class="subsection-level-extent" id="General-idea">
<div class="nav-panel">
<p>
Next: <a href="#Error-handling" accesskey="n" rel="next">Error handling</a>, Up: <a href="#Introduction-to-the-library" accesskey="u" rel="up">Introduction</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="General-idea-1"><span>6.1.1 General idea<a class="copiable-link" href="#General-idea-1"> &para;</a></span></h4>

<p>A brief description of how <abbr class="acronym">GnuTLS</abbr> sessions operate is shown
at <a class="ref" href="#fig_002dgnutls_002ddesign">Figure 6.1</a>. This section will become more clear when it
is completely read.
As shown in the figure, there is a read-only global state that is
initialized once by the global initialization function.  This global
structure, among others, contains the memory allocation functions
used, structures needed for the <abbr class="acronym">ASN.1</abbr> parser and depending
on the system&rsquo;s CPU, pointers to hardware accelerated encryption functions.  This
structure is never modified by any <abbr class="acronym">GnuTLS</abbr> function, except
for the deinitialization function which frees all allocated memory
and must be called after the program has permanently
finished using <abbr class="acronym">GnuTLS</abbr>.
</p>
<div class="float" id="fig_002dgnutls_002ddesign">
<img class="image" src="gnutls-internals.png" alt="gnutls-internals">
<div class="caption"><p><strong class="strong">Figure 6.1: </strong>High level design of GnuTLS.</p></div></div>
<p>The credentials structures are used by the authentication methods, such
as certificate authentication. They store certificates, privates keys,
and other information that is needed to prove the identity to the peer,
and/or verify the identity of the peer. The information stored in
the credentials structures is initialized once and then can be
shared by many <abbr class="acronym">TLS</abbr> sessions.
</p>
<p>A <abbr class="acronym">GnuTLS</abbr> session contains all the required state and
information to handle one secure connection. The session communicates with the
peers using the provided functions of the transport layer.
Every session has a unique session ID shared with the peer.
</p>
<p>Since TLS sessions can be resumed, servers need a
database back-end to hold the session&rsquo;s parameters.  Every
<abbr class="acronym">GnuTLS</abbr> session after a successful handshake calls the
appropriate back-end function (see <a class="ref" href="#resume">resume</a>)
to store the newly negotiated session. The session
database is examined by the server just after having received the
client hello<a class="footnote" id="DOCF16" href="#FOOT16"><sup>16</sup></a>,
and if the session ID sent by the client, matches a stored session,
the stored session will be retrieved, and the new session will be a
resumed one, and will share the same session ID with the previous one.
</p>
<hr>
</div>
<div class="subsection-level-extent" id="Error-handling">
<div class="nav-panel">
<p>
Next: <a href="#Common-types" accesskey="n" rel="next">Common types</a>, Previous: <a href="#General-idea" accesskey="p" rel="prev">General idea</a>, Up: <a href="#Introduction-to-the-library" accesskey="u" rel="up">Introduction</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Error-handling-1"><span>6.1.2 Error handling<a class="copiable-link" href="#Error-handling-1"> &para;</a></span></h4>

<p>There two types of <abbr class="acronym">GnuTLS</abbr> functions. The first type returns
a boolean value, true (non-zero) or false (zero) value; these functions
are defined to return an unsigned integer type. The other type returns a
signed integer type with zero (or a positive number) indicating
success and a negative value indicating failure. For the latter
type it is recommended to check for errors as following.
</p><div class="example">
<pre class="example-preformatted">    ret = gnutls_function();
    if (ret &lt; 0) {
        return -1;
    }
</pre></div>
<p>The above example checks for a failure condition rather than
for explicit success (e.g., equality to zero). That has the advantage
that future extensions of the API can be extended to provide
additional information via positive returned values (see for example
<a class="ref" href="#gnutls_005fcertificate_005fset_005fx509_005fkey_005ffile">gnutls_certificate_set_x509_key_file</a>).
</p>
<p>In <abbr class="acronym">GnuTLS</abbr>, many objects are represented as opaque types that
are initialized by passing an address to storage of that type to a
pointer parameter of a function name <code class="code">gnutls_<var class="var">obj</var>_init</code>, and
which have a counterpart function <code class="code">gnutls_<var class="var">obj</var>_deinit</code>.  It
is safe, but not mandatory, to pre-initialize the opaque storage to
contain all zeroes (such as by using <code class="code">calloc()</code> or
<code class="code">memset()</code>).  If the initializer succeeds, the storage must be
passed to the counterpart deinitializer when the object is no longer
in use to avoid memory leaks.  As of version 3.8.0, if the initializer
function fails, it is safe, but not mandatory, to call the counterpart
deinitializer, regardless of whether the storage was pre-initialized.
However, this was not guaranteed in earlier versions; for maximum
portability to older library versions, callers should either
pre-initialize the storage to zero before initialization or refrain
from calling the deinitializer if the initializer fails.
</p>
<p>For certain operations such as TLS handshake and TLS packet receive
there is the notion of fatal and non-fatal error codes.
Fatal errors terminate the TLS session immediately and further sends
and receives will be disallowed.  Such an example is
<code class="code">GNUTLS_E_DECRYPTION_FAILED</code>. Non-fatal errors may warn about
something, i.e., a warning alert was received, or indicate the some
action has to be taken. This is the case with the error code
<code class="code">GNUTLS_E_REHANDSHAKE</code> returned by <a class="ref" href="#gnutls_005frecord_005frecv">gnutls_record_recv</a>.
This error code indicates that the server requests a re-handshake. The
client may ignore this request, or may reply with an alert.  You can
test if an error code is a fatal one by using the
<a class="ref" href="#gnutls_005ferror_005fis_005ffatal">gnutls_error_is_fatal</a>.
All errors can be converted to a descriptive string using <a class="ref" href="#gnutls_005fstrerror">gnutls_strerror</a>.
</p>
<p>If any non fatal errors, that require an action, are to be returned by
a function, these error codes will be documented in the function&rsquo;s
reference. For example the error codes <code class="code">GNUTLS_E_WARNING_ALERT_RECEIVED</code> and <code class="code">GNUTLS_E_FATAL_ALERT_RECEIVED</code>
that may returned when receiving data, should be handled by notifying the
user of the alert (as explained in <a class="ref" href="#Handling-alerts">Handling alerts</a>).
See <a class="ref" href="#Error-codes">Error Codes and Descriptions</a>, for a description of the available error codes.
</p>
<hr>
</div>
<div class="subsection-level-extent" id="Common-types">
<div class="nav-panel">
<p>
Next: <a href="#Debugging-and-auditing" accesskey="n" rel="next">Debugging and auditing</a>, Previous: <a href="#Error-handling" accesskey="p" rel="prev">Error handling</a>, Up: <a href="#Introduction-to-the-library" accesskey="u" rel="up">Introduction</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Common-types-1"><span>6.1.3 Common types<a class="copiable-link" href="#Common-types-1"> &para;</a></span></h4>
<a class="index-entry-id" id="index-gnutls_005fdatum_005ft"></a>
<a class="index-entry-id" id="index-giovec_005ft"></a>

<p>All strings that are to provided as input to <abbr class="acronym">GnuTLS</abbr> functions
should be in UTF-8 unless otherwise specified. Output strings are also
in UTF-8 format unless otherwise specified. When functions take as input
passwords, they will normalize them using [<a class="ref" href="#RFC7613">RFC7613</a>] rules (since
GnuTLS 3.5.7).
</p>
<p>When data of a fixed size are provided to <abbr class="acronym">GnuTLS</abbr> functions then
the helper structure <code class="code">gnutls_datum_t</code> is often used. Its definition is
shown below.
</p><pre class="verbatim">  typedef struct
  {
    unsigned char *data;
    unsigned int size;
  } gnutls_datum_t;
</pre>
<p>In functions where this structure is a returned type, if the function succeeds,
it is expected from the caller to use <code class="code">gnutls_free()</code> to deinitialize the
data element after use, unless otherwise specified. If the function fails, the
contents of the <code class="code">gnutls_datum_t</code> should be considered undefined and must
not be deinitialized.
</p>
<p>Other functions that require data for scattered read use a structure similar
to <code class="code">struct iovec</code> typically used by <code class="code">readv</code>. It is shown
below.
</p><pre class="verbatim">  typedef struct
  {
    void *iov_base;             /* Starting address */
    size_t iov_len;             /* Number of bytes to transfer */
  } giovec_t;
</pre>

<hr>
</div>
<div class="subsection-level-extent" id="Debugging-and-auditing">
<div class="nav-panel">
<p>
Next: <a href="#Thread-safety" accesskey="n" rel="next">Thread safety</a>, Previous: <a href="#Common-types" accesskey="p" rel="prev">Common types</a>, Up: <a href="#Introduction-to-the-library" accesskey="u" rel="up">Introduction</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Debugging-and-auditing-1"><span>6.1.4 Debugging and auditing<a class="copiable-link" href="#Debugging-and-auditing-1"> &para;</a></span></h4>

<p>In many cases things may not go as expected and further information,
to assist debugging, from <abbr class="acronym">GnuTLS</abbr> is desired.
Those are the cases where the <a class="ref" href="#gnutls_005fglobal_005fset_005flog_005flevel">gnutls_global_set_log_level</a> and
<a class="ref" href="#gnutls_005fglobal_005fset_005flog_005ffunction">gnutls_global_set_log_function</a> are to be used. Those will print
verbose information on the <abbr class="acronym">GnuTLS</abbr> functions internal flow.
</p>
<dl class="table">
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fglobal_005fset_005flog_005flevel">gnutls_global_set_log_level</a> (int <var class="var">level</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fglobal_005fset_005flog_005ffunction">gnutls_global_set_log_function</a> (gnutls_log_func <var class="var">log_func</var>)</code></dt>
</dl>

<p>Alternatively the environment variable <code class="code">GNUTLS_DEBUG_LEVEL</code> can be
set to a logging level and GnuTLS will output debugging output to standard
error. Other available environment variables are shown in <a class="ref" href="#tab_003aenvironment">Table 6.1</a>.
</p>
<div class="float" id="tab_003aenvironment">
<table class="multitable">
<thead><tr><th width="30%">Variable</th><th width="70%">Purpose</th></tr></thead>
<tbody><tr><td width="30%"><code class="code">GNUTLS_DEBUG_LEVEL</code></td><td width="70%">When set to a numeric value, it sets the default debugging level for GnuTLS applications.</td></tr>
<tr><td width="30%"><code class="code">SSLKEYLOGFILE</code></td><td width="70%">When set to a filename, GnuTLS will append to it the session keys in the NSS Key Log
format. That format can be read by wireshark and will allow decryption of the session for debugging.</td></tr>
<tr><td width="30%"><code class="code">GNUTLS_CPUID_OVERRIDE</code></td><td width="70%">That environment variable can be used to
explicitly enable/disable the use of certain CPU capabilities. Note that CPU
detection cannot be overridden, i.e., VIA options cannot be enabled on an Intel
CPU. The currently available options are:
<ul class="itemize mark-bullet">
<li>0x1: Disable all run-time detected optimizations
</li><li>0x2: Enable AES-NI
</li><li>0x4: Enable SSSE3
</li><li>0x8: Enable PCLMUL
</li><li>0x10: Enable AVX
</li><li>0x20: Enable SHA_NI
</li><li>0x100000: Enable VIA padlock
</li><li>0x200000: Enable VIA PHE
</li><li>0x400000: Enable VIA PHE SHA512
</li></ul></td></tr>
<tr><td width="30%"><code class="code">GNUTLS_FORCE_FIPS_MODE</code></td><td width="70%">In setups where GnuTLS is compiled with support for FIPS140-2 (see <a class="ref" href="#FIPS140_002d2-mode">FIPS140-2 mode</a>)
if set to one it will force the FIPS mode enablement.</td></tr>
</tbody>
</table>
<div class="caption"><p><strong class="strong">Table 6.1: </strong>Environment variables used by the library.</p></div></div>

<p>When debugging is not required, important issues, such as detected
attacks on the protocol still need to be logged. This is provided
by the logging function set by
<a class="ref" href="#gnutls_005fglobal_005fset_005faudit_005flog_005ffunction">gnutls_global_set_audit_log_function</a>. The provided function
will receive an message and the corresponding
TLS session. The session information might be used to derive IP addresses
or other information about the peer involved.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fglobal_005fset_005faudit_005flog_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_global_set_audit_log_function</strong> <code class="def-code-arguments">(gnutls_audit_log_func <var class="var">log_func</var>)</code><a class="copiable-link" href="#index-gnutls_005fglobal_005fset_005faudit_005flog_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">log_func</var>: it is the audit log function
</p>
<p>This is the function to set the audit logging function. This
is a function to report important issues, such as possible
attacks in the protocol. This is different from <code class="code">gnutls_global_set_log_function()</code> 
because it will report also session-specific events. The session
parameter will be null if there is no corresponding TLS session.
</p>
<p><code class="code">gnutls_audit_log_func</code> is of the form,
void (*gnutls_audit_log_func)( gnutls_session_t, const char*);
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<hr>
</div>
<div class="subsection-level-extent" id="Thread-safety">
<div class="nav-panel">
<p>
Next: <a href="#Running-in-a-sandbox" accesskey="n" rel="next">Running in a sandbox</a>, Previous: <a href="#Debugging-and-auditing" accesskey="p" rel="prev">Debugging and auditing</a>, Up: <a href="#Introduction-to-the-library" accesskey="u" rel="up">Introduction</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Thread-safety-1"><span>6.1.5 Thread safety<a class="copiable-link" href="#Thread-safety-1"> &para;</a></span></h4>
<a class="index-entry-id" id="index-thread-safety"></a>

<p>The <abbr class="acronym">GnuTLS</abbr> library is thread safe by design, meaning that
objects of the library such as TLS sessions, can be safely divided across
threads as long as a single thread accesses a single object. This is
sufficient to support a server which handles several sessions per thread.
Read-only access to objects, for example the credentials holding structures,
is also thread-safe.
</p>
<p>A <code class="code">gnutls_session_t</code> object could also be shared by two threads, one sending,
the other receiving. However, care must be taken on the following use cases:
</p><ul class="itemize mark-bullet">
<li>The re-handshake process in TLS 1.2 or earlier must be handled only in
a single thread and no other thread may be performing any operation.
</li><li>The flag <code class="code">GNUTLS_AUTO_REAUTH</code> cannot be used safely in this mode of operation.
</li><li>Any other operation which may send or receive data, like key update (c.f.,
<a class="ref" href="#gnutls_005fsession_005fkey_005fupdate">gnutls_session_key_update</a>), must not be performed while threads
are receiving or writing.
</li><li>The termination of a session should be handled, either by a single thread being
active, or by the sender thread using <a class="ref" href="#gnutls_005fbye">gnutls_bye</a> with <code class="code">GNUTLS_SHUT_WR</code>
and the receiving thread waiting for a return value of zero (or timeout on
certain servers which do not respond).
</li><li>The functions <a class="ref" href="#gnutls_005ftransport_005fset_005ferrno">gnutls_transport_set_errno</a> and <a class="ref" href="#gnutls_005frecord_005fget_005fdirection">gnutls_record_get_direction</a>
should not be relied during parallel operation.
</li></ul>

<p>For several aspects of the library (e.g., the random generator, PKCS#11
operations), the library may utilize mutex locks (e.g., pthreads on GNU/Linux and CriticalSection on Windows)
which are transparently setup on library initialization. Prior to version 3.3.0
these were setup by explicitly calling <a class="ref" href="#gnutls_005fglobal_005finit">gnutls_global_init</a>.<a class="footnote" id="DOCF17" href="#FOOT17"><sup>17</sup></a>
</p>
<p>Note that, on Glibc systems, unless the application is explicitly linked
with the libpthread library, no mutex locks are used and setup by GnuTLS. It
will use the Glibc mutex stubs.
</p>
<hr>
</div>
<div class="subsection-level-extent" id="Running-in-a-sandbox">
<div class="nav-panel">
<p>
Next: <a href="#Sessions-and-fork" accesskey="n" rel="next">Sessions and fork</a>, Previous: <a href="#Thread-safety" accesskey="p" rel="prev">Thread safety</a>, Up: <a href="#Introduction-to-the-library" accesskey="u" rel="up">Introduction</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Running-in-a-sandbox-1"><span>6.1.6 Running in a sandbox<a class="copiable-link" href="#Running-in-a-sandbox-1"> &para;</a></span></h4>
<a class="index-entry-id" id="index-seccomp"></a>
<a class="index-entry-id" id="index-isolated-mode"></a>

<p>Given that TLS protocol handling as well as X.509 certificate
parsing are complicated processes involving several thousands lines of code,
it is often desirable (and recommended) to run the TLS session handling in
a sandbox like seccomp. That has to be allowed by the overall software design,
but if available, it adds an additional layer of protection by
preventing parsing errors from becoming vessels for further security issues such
as code execution.
</p>
<p>GnuTLS requires the following system calls to be available for its proper
operation.
</p>
<ul class="itemize mark-bullet">
<li>nanosleep
</li><li>time
</li><li>gettimeofday
</li><li>clock_gettime
</li><li>getrusage
</li><li>getpid
</li><li>send
</li><li>recv
</li><li>sendmsg
</li><li>read (to read from /dev/urandom)
</li><li>getrandom (this is Linux-kernel specific)
</li><li>poll
</li></ul>

<p>As well as any calls needed for memory allocation to work. Note however, that GnuTLS
depends on libc for the system calls, and there is no guarantee that libc will
call the expected system call. For that it is recommended to test your
program in all the targeted platforms when filters like seccomp are in place.
</p>
<p>An example with a seccomp filter from GnuTLS&rsquo; test suite is at:
<a class="url" href="https://gitlab.com/gnutls/gnutls/blob/master/tests/seccomp.c">https://gitlab.com/gnutls/gnutls/blob/master/tests/seccomp.c</a>.
</p>
<hr>
</div>
<div class="subsection-level-extent" id="Sessions-and-fork">
<div class="nav-panel">
<p>
Next: <a href="#Callback-functions" accesskey="n" rel="next">Callback functions</a>, Previous: <a href="#Running-in-a-sandbox" accesskey="p" rel="prev">Running in a sandbox</a>, Up: <a href="#Introduction-to-the-library" accesskey="u" rel="up">Introduction</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Sessions-and-fork-1"><span>6.1.7 Sessions and fork<a class="copiable-link" href="#Sessions-and-fork-1"> &para;</a></span></h4>
<a class="index-entry-id" id="index-fork"></a>

<p>A <code class="code">gnutls_session_t</code> object can be shared by two processes after a fork,
one sending, the other receiving. In that case rehandshakes,
cannot and must not be performed. As with threads, the termination of a session should be
handled by the sender process using <a class="ref" href="#gnutls_005fbye">gnutls_bye</a> with <code class="code">GNUTLS_SHUT_WR</code>
and the receiving process waiting for a return value of zero.
</p>

<hr>
</div>
<div class="subsection-level-extent" id="Callback-functions">
<div class="nav-panel">
<p>
Previous: <a href="#Sessions-and-fork" accesskey="p" rel="prev">Sessions and fork</a>, Up: <a href="#Introduction-to-the-library" accesskey="u" rel="up">Introduction</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Callback-functions-1"><span>6.1.8 Callback functions<a class="copiable-link" href="#Callback-functions-1"> &para;</a></span></h4>
<a class="index-entry-id" id="index-callback-functions"></a>

<p>There are several cases where <abbr class="acronym">GnuTLS</abbr> may need out of
band input from your program. This is now implemented using some
callback functions, which your program is expected to register.
</p>
<p>An example of this type of functions are the push and pull callbacks
which are used to specify the functions that will retrieve and send
data to the transport layer.
</p>
<dl class="table">
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005ftransport_005fset_005fpush_005ffunction">gnutls_transport_set_push_function</a> (gnutls_session_t <var class="var">session</var>, gnutls_push_func <var class="var">push_func</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005ftransport_005fset_005fpull_005ffunction">gnutls_transport_set_pull_function</a> (gnutls_session_t <var class="var">session</var>, gnutls_pull_func <var class="var">pull_func</var>)</code></dt>
</dl>

<p>Other callback functions may require more complicated input and data
to be allocated. Such an example is
<a class="ref" href="#gnutls_005fsrp_005fset_005fserver_005fcredentials_005ffunction">gnutls_srp_set_server_credentials_function</a>.
All callbacks should allocate and free memory using
<code class="code">gnutls_malloc</code> and <code class="code">gnutls_free</code>.
</p>

<hr>
</div>
</div>
<div class="section-level-extent" id="Preparation">
<div class="nav-panel">
<p>
Next: <a href="#Session-initialization" accesskey="n" rel="next">Session initialization</a>, Previous: <a href="#Introduction-to-the-library" accesskey="p" rel="prev">Introduction</a>, Up: <a href="#How-to-use-GnuTLS-in-applications" accesskey="u" rel="up">How to use <abbr class="acronym">GnuTLS</abbr> in applications</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Preparation-1"><span>6.2 Preparation<a class="copiable-link" href="#Preparation-1"> &para;</a></span></h3>

<p>To use <abbr class="acronym">GnuTLS</abbr>, you have to perform some changes to your
sources and your build system. The necessary changes are explained in
the following subsections.
</p>

<ul class="mini-toc">
<li><a href="#Headers" accesskey="1">Headers</a></li>
<li><a href="#Initialization" accesskey="2">Initialization</a></li>
<li><a href="#Version-check" accesskey="3">Version check</a></li>
<li><a href="#Building-the-source" accesskey="4">Building the source</a></li>
</ul>
<hr>
<div class="subsection-level-extent" id="Headers">
<div class="nav-panel">
<p>
Next: <a href="#Initialization" accesskey="n" rel="next">Initialization</a>, Up: <a href="#Preparation" accesskey="u" rel="up">Preparation</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Headers-1"><span>6.2.1 Headers<a class="copiable-link" href="#Headers-1"> &para;</a></span></h4>

<p>All the data types and functions of the <abbr class="acronym">GnuTLS</abbr> library are
defined in the header file <samp class="file">gnutls/gnutls.h</samp>.  This must be
included in all programs that make use of the <abbr class="acronym">GnuTLS</abbr>
library.
</p>
<hr>
</div>
<div class="subsection-level-extent" id="Initialization">
<div class="nav-panel">
<p>
Next: <a href="#Version-check" accesskey="n" rel="next">Version check</a>, Previous: <a href="#Headers" accesskey="p" rel="prev">Headers</a>, Up: <a href="#Preparation" accesskey="u" rel="up">Preparation</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Initialization-2"><span>6.2.2 Initialization<a class="copiable-link" href="#Initialization-2"> &para;</a></span></h4>

<p>The GnuTLS library is initialized on load; prior to 3.3.0 was initialized by calling <a class="ref" href="#gnutls_005fglobal_005finit">gnutls_global_init</a><a class="footnote" id="DOCF18" href="#FOOT18"><sup>18</sup></a>. <a class="ref" href="#gnutls_005fglobal_005finit">gnutls_global_init</a> in
versions after 3.3.0 is thread-safe (see <a class="ref" href="#Thread-safety">Thread safety</a>).
</p>
<p>The initialization typically enables CPU-specific acceleration, performs any required
precalculations needed, opens any required system devices (e.g., /dev/urandom on Linux)
and initializes subsystems that could be used later.
</p>
<p>The resources allocated by the initialization process will be released
on library deinitialization.
</p>
<p>Note that on certain systems file descriptors may be kept open by
GnuTLS (e.g. /dev/urandom) on library load. Applications closing all unknown file
descriptors must immediately call <a class="ref" href="#gnutls_005fglobal_005finit">gnutls_global_init</a>, after that, to
ensure they don&rsquo;t disrupt GnuTLS&rsquo; operation.
</p>

<hr>
</div>
<div class="subsection-level-extent" id="Version-check">
<div class="nav-panel">
<p>
Next: <a href="#Building-the-source" accesskey="n" rel="next">Building the source</a>, Previous: <a href="#Initialization" accesskey="p" rel="prev">Initialization</a>, Up: <a href="#Preparation" accesskey="u" rel="up">Preparation</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Version-check-1"><span>6.2.3 Version check<a class="copiable-link" href="#Version-check-1"> &para;</a></span></h4>

<p>It is often desirable to check that the version of &lsquo;gnutls&rsquo; used is
indeed one which fits all requirements.  Even with binary
compatibility new features may have been introduced but due to problem
with the dynamic linker an old version is actually used.  So you may
want to check that the version is okay right after program start-up.
See the function <a class="ref" href="#gnutls_005fcheck_005fversion">gnutls_check_version</a>.
</p>
<p>On the other hand, it is often desirable to support more than one
versions of the library. In that case you could utilize compile-time
feature checks using the <code class="code">GNUTLS_VERSION_NUMBER</code> macro.
For example, to conditionally add code for GnuTLS 3.2.1 or later, you may use:
</p><div class="example">
<pre class="example-preformatted">#if GNUTLS_VERSION_NUMBER &gt;= 0x030201
 ...
#endif
</pre></div>

<hr>
</div>
<div class="subsection-level-extent" id="Building-the-source">
<div class="nav-panel">
<p>
Previous: <a href="#Version-check" accesskey="p" rel="prev">Version check</a>, Up: <a href="#Preparation" accesskey="u" rel="up">Preparation</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Building-the-source-1"><span>6.2.4 Building the source<a class="copiable-link" href="#Building-the-source-1"> &para;</a></span></h4>

<p>If you want to compile a source file including the
<samp class="file">gnutls/gnutls.h</samp> header file, you must make sure that the
compiler can find it in the directory hierarchy.  This is accomplished
by adding the path to the directory in which the header file is
located to the compilers include file search path (via the <samp class="option">-I</samp>
option).
</p>
<p>However, the path to the include file is determined at the time the
source is configured.  To solve this problem, the library uses the
external package <code class="command">pkg-config</code> that knows the path to the
include file and other configuration options.  The options that need
to be added to the compiler invocation at compile time are output by
the <samp class="option">--cflags</samp> option to <code class="command">pkg-config gnutls</code>.  The
following example shows how it can be used at the command line:
</p>
<div class="example">
<pre class="example-preformatted">gcc -c foo.c `pkg-config gnutls --cflags`
</pre></div>

<p>Adding the output of &lsquo;<samp class="samp">pkg-config gnutls --cflags</samp>&rsquo; to the
compilers command line will ensure that the compiler can find the
<samp class="file">gnutls/gnutls.h</samp> header file.
</p>
<p>A similar problem occurs when linking the program with the library.
Again, the compiler has to find the library files.  For this to work,
the path to the library files has to be added to the library search
path (via the <samp class="option">-L</samp> option).  For this, the option
<samp class="option">--libs</samp> to <code class="command">pkg-config gnutls</code> can be used.  For
convenience, this option also outputs all other options that are
required to link the program with the library (for instance, the
&lsquo;<samp class="samp">-ltasn1</samp>&rsquo; option).  The example shows how to link <samp class="file">foo.o</samp>
with the library to a program <code class="command">foo</code>.
</p>
<div class="example">
<pre class="example-preformatted">gcc -o foo foo.o `pkg-config gnutls --libs`
</pre></div>

<p>Of course you can also combine both examples to a single command by
specifying both options to <code class="command">pkg-config</code>:
</p>
<div class="example">
<pre class="example-preformatted">gcc -o foo foo.c `pkg-config gnutls --cflags --libs`
</pre></div>

<p>When a program uses the GNU autoconf system, then the following
line or similar can be used to detect the presence of GnuTLS.
</p>
<div class="example">
<pre class="example-preformatted">PKG_CHECK_MODULES([LIBGNUTLS], [gnutls &gt;= 3.3.0])

AC_SUBST([LIBGNUTLS_CFLAGS])
AC_SUBST([LIBGNUTLS_LIBS])
</pre></div>

<hr>
</div>
</div>
<div class="section-level-extent" id="Session-initialization">
<div class="nav-panel">
<p>
Next: <a href="#Associating-the-credentials" accesskey="n" rel="next">Associating the credentials</a>, Previous: <a href="#Preparation" accesskey="p" rel="prev">Preparation</a>, Up: <a href="#How-to-use-GnuTLS-in-applications" accesskey="u" rel="up">How to use <abbr class="acronym">GnuTLS</abbr> in applications</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Session-initialization-1"><span>6.3 Session initialization<a class="copiable-link" href="#Session-initialization-1"> &para;</a></span></h3>

<p>In the previous sections we have discussed the global initialization
required for GnuTLS as well as the initialization required for each
authentication method&rsquo;s credentials (see <a class="ref" href="#Authentication">Authentication</a>).
In this section we elaborate on the TLS or DTLS session initiation.
Each session is initialized using <a class="ref" href="#gnutls_005finit">gnutls_init</a> which among
others is used to specify the type of the connection (server or client),
and the underlying protocol type, i.e., datagram (UDP) or reliable (TCP).
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005finit"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_init</strong> <code class="def-code-arguments">(gnutls_session_t * <var class="var">session</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005finit"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a pointer to a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">flags</var>: indicate if this session is to be used for server or client.
</p>
<p>This function initializes the provided session. Every session must
be initialized before use, and after successful initialization and
use must be deinitialized by calling <code class="code">gnutls_deinit()</code> .
</p>
<p><code class="code">flags</code> can be any combination of flags from <code class="code">gnutls_init_flags_t</code> .
</p>
<p>Note that since version 3.1.2 this function enables some common
TLS extensions such as session tickets and OCSP certificate status
request in client side by default. To prevent that use the <code class="code">GNUTLS_NO_DEFAULT_EXTENSIONS</code> 
flag.
</p>
<p>Note that it is never mandatory to use <code class="code">gnutls_deinit()</code>  after this
function fails.  Since gnutls 3.8.0, it is safe to unconditionally
use <code class="code">gnutls_deinit()</code>  even after failure regardless of whether the
memory was initialized prior to <code class="code">gnutls_init()</code> ; however, clients
wanting to be portable to older versions of the library should
either skip deinitialization on failure, or pre-initialize the
memory passed in to <code class="code">gnutls_init()</code>  to all zeroes via <code class="code">memset()</code>  or
similar.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, or an error code.
</p></dd></dl>

<div class="float" id="gnutls_005finit_005fflags_005ft">


<dl class="table">
<dt><code class="code">GNUTLS_SERVER</code></dt>
<dd><p>Connection end is a server.
</p></dd>
<dt><code class="code">GNUTLS_CLIENT</code></dt>
<dd><p>Connection end is a client.
</p></dd>
<dt><code class="code">GNUTLS_DATAGRAM</code></dt>
<dd><p>Connection is datagram oriented (DTLS). Since 3.0.0.
</p></dd>
<dt><code class="code">GNUTLS_NONBLOCK</code></dt>
<dd><p>Connection should not block. Since 3.0.0.
</p></dd>
<dt><code class="code">GNUTLS_NO_DEFAULT_EXTENSIONS</code></dt>
<dd><p>Do not enable any TLS extensions by default such as session tickets and OCSP certificate status request (since 3.1.2). As TLS 1.2 and later require extensions this option is considered obsolete and should not be used.
</p></dd>
<dt><code class="code">GNUTLS_NO_REPLAY_PROTECTION</code></dt>
<dd><p>Disable any replay protection in DTLS. This must only be used if  replay protection is achieved using other means. Since 3.2.2.
</p></dd>
<dt><code class="code">GNUTLS_NO_SIGNAL</code></dt>
<dd><p>In systems where SIGPIPE is delivered on send, it will be disabled. That flag has effect in systems which support the MSG_NOSIGNAL sockets flag (since 3.4.2).
</p></dd>
<dt><code class="code">GNUTLS_ALLOW_ID_CHANGE</code></dt>
<dd><p>Allow the peer to replace its certificate, or change its ID during a rehandshake. This change is often used in attacks and thus prohibited by default. Since 3.5.0.
</p></dd>
<dt><code class="code">GNUTLS_ENABLE_FALSE_START</code></dt>
<dd><p>Enable the TLS false start on client side if the negotiated ciphersuites allow it. This will enable sending data prior to the handshake being complete, and may introduce a risk of crypto failure when combined with certain key exchanged; for that GnuTLS may not enable that option in ciphersuites that are known to be not safe for false start. Since 3.5.0.
</p></dd>
<dt><code class="code">GNUTLS_FORCE_CLIENT_CERT</code></dt>
<dd><p>When in client side and only a single cert is specified, send that certificate irrespective of the issuers expected by the server. Since 3.5.0.
</p></dd>
<dt><code class="code">GNUTLS_NO_TICKETS</code></dt>
<dd><p>Flag to indicate that the session should not use resumption with session tickets.
</p></dd>
<dt><code class="code">GNUTLS_KEY_SHARE_TOP</code></dt>
<dd><p>Generate key share for the first group which is enabled.
For example x25519. This option is the most performant for client (less CPU spent
generating keys), but if the server doesn&rsquo;t support the advertised option it may
result to more roundtrips needed to discover the server&rsquo;s choice.
</p></dd>
<dt><code class="code">GNUTLS_KEY_SHARE_TOP2</code></dt>
<dd><p>Generate key shares for the top-2 different groups which are enabled.
For example (ECDH + x25519). This is the default.
</p></dd>
<dt><code class="code">GNUTLS_KEY_SHARE_TOP3</code></dt>
<dd><p>Generate key shares for the top-3 different groups which are enabled.
That is, as each group is associated with a key type (EC, finite field, x25519), generate
three keys using <code class="code">GNUTLS_PK_DH</code> , <code class="code">GNUTLS_PK_EC</code> , <code class="code">GNUTLS_PK_ECDH_X25519</code>  if all of them are enabled.
</p></dd>
<dt><code class="code">GNUTLS_POST_HANDSHAKE_AUTH</code></dt>
<dd><p>Enable post handshake authentication for server and client. When set and
a server requests authentication after handshake <code class="code">GNUTLS_E_REAUTH_REQUEST</code>  will be returned
by <code class="code">gnutls_record_recv()</code> . A client should then call <code class="code">gnutls_reauth()</code>  to re-authenticate.
</p></dd>
<dt><code class="code">GNUTLS_NO_AUTO_REKEY</code></dt>
<dd><p>Disable auto-rekeying under TLS1.3. If this option is not specified
gnutls will force a rekey after 2^24 records have been sent.
</p></dd>
<dt><code class="code">GNUTLS_SAFE_PADDING_CHECK</code></dt>
<dd><p>Flag to indicate that the TLS 1.3 padding check will be done in a
safe way which doesn&rsquo;t leak the pad size based on GnuTLS processing time. This is of use to
applications which hide the length of transferred data via the TLS1.3 padding mechanism and
are already taking steps to hide the data processing time. This comes at a performance
penalty.
</p></dd>
<dt><code class="code">GNUTLS_ENABLE_EARLY_START</code></dt>
<dd><p>Under TLS1.3 allow the server to return earlier than the full handshake
finish; similarly to false start the handshake will be completed once data are received by the
client, while the server is able to transmit sooner. This is not enabled by default as it could
break certain existing server assumptions and use-cases. Since 3.6.4.
</p></dd>
<dt><code class="code">GNUTLS_ENABLE_RAWPK</code></dt>
<dd><p>Allows raw public-keys to be negotiated during the handshake. Since 3.6.6.
</p></dd>
<dt><code class="code">GNUTLS_AUTO_REAUTH</code></dt>
<dd><p>Enable transparent re-authentication in client side when the server
requests to. That is, reauthentication is handled within <code class="code">gnutls_record_recv()</code> , and
the <code class="code">GNUTLS_E_REHANDSHAKE</code>  or <code class="code">GNUTLS_E_REAUTH_REQUEST</code>  are not returned. This must be
enabled with <code class="code">GNUTLS_POST_HANDSHAKE_AUTH</code>  for TLS1.3. Enabling this flag requires to restore
interrupted calls to <code class="code">gnutls_record_recv()</code>  based on the output of <code class="code">gnutls_record_get_direction()</code> ,
since <code class="code">gnutls_record_recv()</code>  could be interrupted when sending when this flag is enabled.
Note this flag may not be used if you are using the same session for sending and receiving
in different threads.
</p></dd>
<dt><code class="code">GNUTLS_ENABLE_EARLY_DATA</code></dt>
<dd><p>Under TLS1.3 allow the server to receive early data sent as part of the initial ClientHello (0-RTT).
This can also be used to explicitly indicate that the client will send early data.
This is not enabled by default as early data has weaker security properties than other data. Since 3.6.5.
</p></dd>
<dt><code class="code">GNUTLS_NO_AUTO_SEND_TICKET</code></dt>
<dd><p>Under TLS1.3 disable auto-sending of
session tickets during the handshake.
</p></dd>
<dt><code class="code">GNUTLS_NO_END_OF_EARLY_DATA</code></dt>
<dd><p>Under TLS1.3 suppress sending EndOfEarlyData message. Since 3.7.2.
</p></dd>
<dt><code class="code">GNUTLS_NO_TICKETS_TLS12</code></dt>
<dd><p>Flag to indicate that the session should not use resumption with session tickets. This flag only has effect if TLS 1.2 is used.
</p></dd>
<dt><code class="code">GNUTLS_NO_STATUS_REQUEST</code></dt>
<dd><p>Prevents client from including the &quot;status_request&quot; TLS extension
in the client hello, thus disabling the receival of certificate status information. Since 3.8.0.
</p></dd>
</dl>
<div class="caption"><p><strong class="strong">Figure 6.2: </strong>The <code class="code">gnutls_init_flags_t</code> enumeration.</p></div></div>
<p>After the session initialization details on the allowed ciphersuites
and protocol versions should be set using the priority functions
such as <a class="ref" href="#gnutls_005fpriority_005fset">gnutls_priority_set</a> and <a class="ref" href="#gnutls_005fpriority_005fset_005fdirect">gnutls_priority_set_direct</a>.
We elaborate on them in <a class="ref" href="#Priority-Strings">Priority strings</a>.
The credentials used for the key exchange method, such as certificates
or usernames and passwords should also be associated with the session
current session using <a class="ref" href="#gnutls_005fcredentials_005fset">gnutls_credentials_set</a>.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcredentials_005fset"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_credentials_set</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_credentials_type_t <var class="var">type</var>, void * <var class="var">cred</var>)</code><a class="copiable-link" href="#index-gnutls_005fcredentials_005fset"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">type</var>: is the type of the credentials
</p>
<p><var class="var">cred</var>: the credentials to set
</p>
<p>Sets the needed credentials for the specified type.  E.g. username,
password - or public and private keys etc.  The  <code class="code">cred</code> parameter is
a structure that depends on the specified  <code class="code">type</code> and on the current
session (client or server). Only a single  <code class="code">cred</code> may be set for
each different  <code class="code">type</code> , subsequent calls with the same  <code class="code">type</code> will
replace the previously set credentials.
</p>
<p>In order to minimize memory usage, and share credentials between
several threads gnutls keeps a pointer to  <code class="code">cred</code> , and not the whole
cred structure.  Thus you will have to keep the structure allocated
until you call <code class="code">gnutls_deinit()</code> , or a future call of
<code class="code">gnutls_credentials_set()</code>  with the same  <code class="code">type</code> replaces the  <code class="code">cred</code> structure.
</p>
<p>For <code class="code">GNUTLS_CRD_ANON</code> ,  <code class="code">cred</code> should be
<code class="code">gnutls_anon_client_credentials_t</code>  in case of a client.  In case of
a server it should be <code class="code">gnutls_anon_server_credentials_t</code> .
</p>
<p>For <code class="code">GNUTLS_CRD_SRP</code> ,  <code class="code">cred</code> should be <code class="code">gnutls_srp_client_credentials_t</code> 
in case of a client, and <code class="code">gnutls_srp_server_credentials_t</code> , in case
of a server.
</p>
<p>For <code class="code">GNUTLS_CRD_CERTIFICATE</code> ,  <code class="code">cred</code> should be
<code class="code">gnutls_certificate_credentials_t</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned.
</p></dd></dl>

<hr>
</div>
<div class="section-level-extent" id="Associating-the-credentials">
<div class="nav-panel">
<p>
Next: <a href="#Setting-up-the-transport-layer" accesskey="n" rel="next">Setting up the transport layer</a>, Previous: <a href="#Session-initialization" accesskey="p" rel="prev">Session initialization</a>, Up: <a href="#How-to-use-GnuTLS-in-applications" accesskey="u" rel="up">How to use <abbr class="acronym">GnuTLS</abbr> in applications</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Associating-the-credentials-1"><span>6.4 Associating the credentials<a class="copiable-link" href="#Associating-the-credentials-1"> &para;</a></span></h3>


<p>Each authentication method is associated with a key exchange method, and a credentials type.
The contents of the credentials is method-dependent, e.g. certificates
for certificate authentication and should be initialized and associated
with a session (see <a class="ref" href="#gnutls_005fcredentials_005fset">gnutls_credentials_set</a>).  A mapping of the key exchange methods
with the credential types is shown in <a class="ref" href="#tab_003akey_002dexchange_002dcred">Table 6.2</a>.
</p>
<div class="float" id="tab_003akey_002dexchange_002dcred">
<table class="multitable">
<thead><tr><th width="25%">Authentication method</th><th width="25%">Key exchange</th><th width="20%">Client credentials</th><th width="20%">Server credentials</th></tr></thead>
<tbody><tr><td width="25%">Certificate and Raw public-key</td><td width="25%"><code class="code">KX_RSA</code>,
<code class="code">KX_DHE_RSA</code>,
<code class="code">KX_DHE_DSS</code>,
<code class="code">KX_ECDHE_RSA</code>,
<code class="code">KX_ECDHE_ECDSA</code></td><td width="20%"><code class="code">CRD_CERTIFICATE</code></td><td width="20%"><code class="code">CRD_CERTIFICATE</code></td></tr>
<tr><td width="25%">Password and certificate</td><td width="25%"><code class="code">KX_SRP_RSA</code>, <code class="code">KX_SRP_DSS</code></td><td width="20%"><code class="code">CRD_SRP</code></td><td width="20%"><code class="code">CRD_CERTIFICATE</code>, <code class="code">CRD_SRP</code></td></tr>
<tr><td width="25%">Password</td><td width="25%"><code class="code">KX_SRP</code></td><td width="20%"><code class="code">CRD_SRP</code></td><td width="20%"><code class="code">CRD_SRP</code></td></tr>
<tr><td width="25%">Anonymous</td><td width="25%"><code class="code">KX_ANON_DH</code>,
<code class="code">KX_ANON_ECDH</code></td><td width="20%"><code class="code">CRD_ANON</code></td><td width="20%"><code class="code">CRD_ANON</code></td></tr>
<tr><td width="25%">Pre-shared key</td><td width="25%"><code class="code">KX_PSK</code>,
<code class="code">KX_DHE_PSK</code>, <code class="code">KX_ECDHE_PSK</code></td><td width="20%"><code class="code">CRD_PSK</code></td><td width="20%"><code class="code">CRD_PSK</code></td></tr>
</tbody>
</table>
<div class="caption"><p><strong class="strong">Table 6.2: </strong>Key exchange algorithms and the corresponding credential types.</p></div></div>
<ul class="mini-toc">
<li><a href="#Certificate-credentials" accesskey="1">Certificates</a></li>
<li><a href="#Raw-public_002dkey-credentials" accesskey="2">Raw public-keys</a></li>
<li><a href="#SRP-credentials" accesskey="3">SRP</a></li>
<li><a href="#PSK-credentials" accesskey="4">PSK</a></li>
<li><a href="#Anonymous-credentials" accesskey="5">Anonymous</a></li>
</ul>
<hr>
<div class="subsection-level-extent" id="Certificate-credentials">
<div class="nav-panel">
<p>
Next: <a href="#Raw-public_002dkey-credentials" accesskey="n" rel="next">Raw public-keys</a>, Up: <a href="#Associating-the-credentials" accesskey="u" rel="up">Associating the credentials</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Certificates"><span>6.4.1 Certificates<a class="copiable-link" href="#Certificates"> &para;</a></span></h4>
<h4 class="subsubheading" id="Server-certificate-authentication"><span>Server certificate authentication<a class="copiable-link" href="#Server-certificate-authentication"> &para;</a></span></h4>

<p>When using certificates the server is required to have at least one
certificate and private key pair. Clients may not hold such
a pair, but a server could require it. In this section we discuss
general issues applying to both client and server certificates. The next
section will elaborate on issues arising from client authentication only.
</p>
<p>In order to use certificate credentials one must first initialize a credentials
structure of type <code class="code">gnutls_certificate_credentials_t</code>. After use this structure must
be freed. This can be done with the following functions.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fcertificate_005fallocate_005fcredentials">gnutls_certificate_allocate_credentials</a> (gnutls_certificate_credentials_t * <var class="var">res</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fcertificate_005ffree_005fcredentials">gnutls_certificate_free_credentials</a> (gnutls_certificate_credentials_t <var class="var">sc</var>)</code></dt>
</dl>

<p>After the credentials structures are initialized, the certificate
and key pair must be loaded. This occurs before any <abbr class="acronym">TLS</abbr>
session is initialized, and the same structures are reused for multiple sessions.
Depending on the certificate type different loading functions
are available, as shown below.
For <abbr class="acronym">X.509</abbr> certificates, the functions will
accept and use a certificate chain that leads to a trusted
authority. The certificate chain must be ordered in such way that every
certificate certifies the one before it. The trusted authority&rsquo;s
certificate need not to be included since the peer should possess it
already.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fcertificate_005fset_005fx509_005fkey_005ffile2">gnutls_certificate_set_x509_key_file2</a> (gnutls_certificate_credentials_t <var class="var">res</var>, const char * <var class="var">certfile</var>, const char * <var class="var">keyfile</var>, gnutls_x509_crt_fmt_t <var class="var">type</var>, const char * <var class="var">pass</var>, unsigned int <var class="var">flags</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fcertificate_005fset_005fx509_005fkey_005fmem2">gnutls_certificate_set_x509_key_mem2</a> (gnutls_certificate_credentials_t <var class="var">res</var>, const gnutls_datum_t * <var class="var">cert</var>, const gnutls_datum_t * <var class="var">key</var>, gnutls_x509_crt_fmt_t <var class="var">type</var>, const char * <var class="var">pass</var>, unsigned int <var class="var">flags</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fcertificate_005fset_005fx509_005fkey">gnutls_certificate_set_x509_key</a> (gnutls_certificate_credentials_t <var class="var">res</var>, gnutls_x509_crt_t * <var class="var">cert_list</var>, int <var class="var">cert_list_size</var>, gnutls_x509_privkey_t <var class="var">key</var>)</code></dt>
</dl>

<p>It is recommended to use the higher level functions such as <a class="ref" href="#gnutls_005fcertificate_005fset_005fx509_005fkey_005ffile2">gnutls_certificate_set_x509_key_file2</a>
which accept not only file names but URLs that specify objects stored in token,
or system certificates and keys (see <a class="ref" href="#Application_002dspecific-keys">System and application-specific keys</a>). For these cases, another important
function is <a class="ref" href="#gnutls_005fcertificate_005fset_005fpin_005ffunction">gnutls_certificate_set_pin_function</a>, that
allows setting a callback function to retrieve a PIN if the input keys are
protected by PIN.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fset_005fpin_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_certificate_set_pin_function</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">cred</var>, gnutls_pin_callback_t <var class="var">fn</var>, void * <var class="var">userdata</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fset_005fpin_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">cred</var>: is a <code class="code">gnutls_certificate_credentials_t</code>  type.
</p>
<p><var class="var">fn</var>: A PIN callback
</p>
<p><var class="var">userdata</var>: Data to be passed in the callback
</p>
<p>This function will set a callback function to be used when
required to access a protected object. This function overrides any other
global PIN functions.
</p>
<p>Note that this function must be called right after initialization
to have effect.
</p>
<p><strong class="strong">Since:</strong> 3.1.0
</p></dd></dl>

<p>If the imported keys and certificates need to be accessed before any TLS session
is established, it is convenient to use <a class="ref" href="#gnutls_005fcertificate_005fset_005fkey">gnutls_certificate_set_key</a>
in combination with <a class="ref" href="#gnutls_005fpcert_005fimport_005fx509_005fraw">gnutls_pcert_import_x509_raw</a> and <a class="ref" href="#gnutls_005fprivkey_005fimport_005fx509_005fraw">gnutls_privkey_import_x509_raw</a>.
</p>



<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fset_005fkey"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_certificate_set_key</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">res</var>, const char ** <var class="var">names</var>, int <var class="var">names_size</var>, gnutls_pcert_st * <var class="var">pcert_list</var>, int <var class="var">pcert_list_size</var>, gnutls_privkey_t <var class="var">key</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fset_005fkey"> &para;</a></span></dt>
<dd><p><var class="var">res</var>: is a <code class="code">gnutls_certificate_credentials_t</code>  type.
</p>
<p><var class="var">names</var>: is an array of DNS names belonging to the public-key (NULL if none)
</p>
<p><var class="var">names_size</var>: holds the size of the names list
</p>
<p><var class="var">pcert_list</var>: contains a certificate list (chain) or raw public-key
</p>
<p><var class="var">pcert_list_size</var>: holds the size of the certificate list
</p>
<p><var class="var">key</var>: is a <code class="code">gnutls_privkey_t</code>  key corresponding to the first public-key in pcert_list
</p>
<p>This function sets a public/private key pair in the
gnutls_certificate_credentials_t type. The given public key may be encapsulated
in a certificate or can be given as a raw key. This function may be
called more than once, in case multiple key pairs exist for
the server. For clients that want to send more than their own end-
entity certificate (e.g., also an intermediate CA cert), the full
certificate chain must be provided in  <code class="code">pcert_list</code> .
</p>
<p>Note that the  <code class="code">key</code> will become part of the credentials structure and must
not be deallocated. It will be automatically deallocated when the  <code class="code">res</code> structure
is deinitialized.
</p>
<p>If this function fails, the  <code class="code">res</code> structure is at an undefined state and it must
not be reused to load other keys or certificates.
</p>
<p>Note that, this function by default returns zero on success and a negative value on error.
Since 3.5.6, when the flag <code class="code">GNUTLS_CERTIFICATE_API_V2</code>  is set using <code class="code">gnutls_certificate_set_flags()</code> 
it returns an index (greater or equal to zero). That index can be used for other functions to refer to the added key-pair.
</p>
<p>Since GnuTLS 3.6.6 this function also handles raw public keys.
</p>
<p><strong class="strong">Returns:</strong> On success this functions returns zero, and otherwise a negative value on error (see above for modifying that behavior).
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<p>If multiple certificates are used with the functions above each
client&rsquo;s request will be served with the certificate that matches the
requested name (see <a class="ref" href="#Server-name-indication">Server name indication</a>).
</p>
<p>As an alternative to loading from files or buffers, a callback may be used for the
server or the client to specify the certificate and the key at the handshake time.
In that case a certificate should be selected according the peer&rsquo;s signature
algorithm preferences. To get those preferences use
<a class="ref" href="#gnutls_005fsign_005falgorithm_005fget_005frequested">gnutls_sign_algorithm_get_requested</a>. Both functions are shown below.
</p>
<dl class="table">
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fcertificate_005fset_005fretrieve_005ffunction">gnutls_certificate_set_retrieve_function</a> (gnutls_certificate_credentials_t <var class="var">cred</var>, gnutls_certificate_retrieve_function * <var class="var">func</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fcertificate_005fset_005fretrieve_005ffunction2">gnutls_certificate_set_retrieve_function2</a> (gnutls_certificate_credentials_t <var class="var">cred</var>, gnutls_certificate_retrieve_function2 * <var class="var">func</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fcertificate_005fset_005fretrieve_005ffunction3">gnutls_certificate_set_retrieve_function3</a> (gnutls_certificate_credentials_t <var class="var">cred</var>, gnutls_certificate_retrieve_function3 * <var class="var">func</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fsign_005falgorithm_005fget_005frequested">gnutls_sign_algorithm_get_requested</a> (gnutls_session_t <var class="var">session</var>, size_t <var class="var">indx</var>, gnutls_sign_algorithm_t * <var class="var">algo</var>)</code></dt>
</dl>

<p>The functions above do not handle the requested server name automatically.
A server would need to check the name requested by the client
using <a class="ref" href="#gnutls_005fserver_005fname_005fget">gnutls_server_name_get</a>, and serve the appropriate
certificate. Note that some of these functions require the <code class="code">gnutls_pcert_st</code> structure to be
filled in. Helper functions to fill in the structure are listed below.
</p>
<pre class="verbatim">typedef struct gnutls_pcert_st
{
  gnutls_pubkey_t pubkey;
  gnutls_datum_t cert;
  gnutls_certificate_type_t type;
} gnutls_pcert_st;
</pre>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpcert_005fimport_005fx509">gnutls_pcert_import_x509</a> (gnutls_pcert_st * <var class="var">pcert</var>, gnutls_x509_crt_t <var class="var">crt</var>, unsigned int <var class="var">flags</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpcert_005fimport_005fx509_005fraw">gnutls_pcert_import_x509_raw</a> (gnutls_pcert_st * <var class="var">pcert</var>, const gnutls_datum_t * <var class="var">cert</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, unsigned int <var class="var">flags</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fpcert_005fdeinit">gnutls_pcert_deinit</a> (gnutls_pcert_st * <var class="var">pcert</var>)</code></dt>
</dl>

<p>In a handshake, the negotiated cipher suite depends on the
certificate&rsquo;s parameters, so some key exchange methods might not be
available with all certificates. <abbr class="acronym">GnuTLS</abbr> will disable
ciphersuites that are not compatible with the key, or the enabled
authentication methods.  For example keys marked as sign-only, will
not be able to access the plain RSA ciphersuites, that require
decryption. It is not recommended to use RSA keys for both
signing and encryption. If possible use a different key for the
<code class="code">DHE-RSA</code> which uses signing and <code class="code">RSA</code> that requires decryption.
All the key exchange methods shown in <a class="ref" href="#tab_003akey_002dexchange">Table 4.1</a> are
available in certificate authentication.
</p>

<h4 class="subsubheading" id="Client-certificate-authentication"><span>Client certificate authentication<a class="copiable-link" href="#Client-certificate-authentication"> &para;</a></span></h4>

<p>If a certificate is to be requested from the client during the handshake, the server
will send a certificate request message. This behavior is controlled by <a class="ref" href="#gnutls_005fcertificate_005fserver_005fset_005frequest">gnutls_certificate_server_set_request</a>.
The request contains a list of the by the server accepted certificate signers. This list
is constructed using the trusted certificate authorities of the server.
In cases where the server supports a large number of certificate authorities
it makes sense not to advertise all of the names to save bandwidth. That can
be controlled using the function <a class="ref" href="#gnutls_005fcertificate_005fsend_005fx509_005frdn_005fsequence">gnutls_certificate_send_x509_rdn_sequence</a>.
This however will have the side-effect of not restricting the client to certificates
signed by server&rsquo;s acceptable signers.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fserver_005fset_005frequest"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_certificate_server_set_request</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_certificate_request_t <var class="var">req</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fserver_005fset_005frequest"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">req</var>: is one of GNUTLS_CERT_REQUEST, GNUTLS_CERT_REQUIRE, GNUTLS_CERT_IGNORE
</p>
<p>This function specifies if we (in case of a server) are going to
send a certificate request message to the client. If  <code class="code">req</code> is
GNUTLS_CERT_REQUIRE then the server will return the <code class="code">GNUTLS_E_NO_CERTIFICATE_FOUND</code> 
error if the peer does not provide a certificate. If you do not call this
function then the client will not be asked to send a certificate. Invoking
the function with  <code class="code">req</code> GNUTLS_CERT_IGNORE has the same effect.
</p></dd></dl>





<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fsend_005fx509_005frdn_005fsequence"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_certificate_send_x509_rdn_sequence</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, int <var class="var">status</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fsend_005fx509_005frdn_005fsequence"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">status</var>: is 0 or 1
</p>
<p>If status is non zero, this function will order gnutls not to send
the rdnSequence in the certificate request message. That is the
server will not advertise its trusted CAs to the peer. If status
is zero then the default behaviour will take effect, which is to
advertise the server&rsquo;s trusted CAs.
</p>
<p>This function has no effect in clients, and in authentication
methods other than certificate with X.509 certificates.
</p></dd></dl>

<p>On the client side, it needs to set its certificates on the credentials
structure, similarly to server side from a file, or via a callback. Once the
certificates are available in the credentials structure, the client will
send them if during the handshake the server requests a certificate signed
by the issuer of its CA.
</p>
<p>In the case a single certificate is available and the server does not
specify a signer&rsquo;s list, then that certificate is always sent. It is,
however possible, to send a certificate even when the advertised CA
list by the server contains CAs other than its signer. That can be achieved
using the <code class="code">GNUTLS_FORCE_CLIENT_CERT</code> flag in <a class="ref" href="#gnutls_005finit">gnutls_init</a>.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fcertificate_005fset_005fx509_005fkey_005ffile">gnutls_certificate_set_x509_key_file</a> (gnutls_certificate_credentials_t <var class="var">res</var>, const char * <var class="var">certfile</var>, const char * <var class="var">keyfile</var>, gnutls_x509_crt_fmt_t <var class="var">type</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fcertificate_005fset_005fx509_005fsimple_005fpkcs12_005ffile">gnutls_certificate_set_x509_simple_pkcs12_file</a> (gnutls_certificate_credentials_t <var class="var">res</var>, const char * <var class="var">pkcs12file</var>, gnutls_x509_crt_fmt_t <var class="var">type</var>, const char * <var class="var">password</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fcertificate_005fset_005fretrieve_005ffunction2">gnutls_certificate_set_retrieve_function2</a> (gnutls_certificate_credentials_t <var class="var">cred</var>, gnutls_certificate_retrieve_function2 * <var class="var">func</var>)</code></dt>
</dl>


<h4 class="subsubheading" id="Client-or-server-certificate-verification"><span>Client or server certificate verification<a class="copiable-link" href="#Client-or-server-certificate-verification"> &para;</a></span></h4>

<p>Certificate verification is possible by loading the trusted
authorities into the credentials structure by using
the following functions, applicable to X.509 certificates.
In modern systems it is recommended to utilize <a class="ref" href="#gnutls_005fcertificate_005fset_005fx509_005fsystem_005ftrust">gnutls_certificate_set_x509_system_trust</a>
which will load the trusted authorities from the system store.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fset_005fx509_005fsystem_005ftrust"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_certificate_set_x509_system_trust</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">cred</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fset_005fx509_005fsystem_005ftrust"> &para;</a></span></dt>
<dd><p><var class="var">cred</var>: is a <code class="code">gnutls_certificate_credentials_t</code>  type.
</p>
<p>This function adds the system&rsquo;s default trusted CAs in order to
verify client or server certificates.
</p>
<p>In the case the system is currently unsupported <code class="code">GNUTLS_E_UNIMPLEMENTED_FEATURE</code> 
is returned.
</p>
<p><strong class="strong">Returns:</strong> the number of certificates processed or a negative error code
on error.
</p>
<p><strong class="strong">Since:</strong> 3.0.20
</p></dd></dl>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fcertificate_005fset_005fx509_005ftrust_005ffile">gnutls_certificate_set_x509_trust_file</a> (gnutls_certificate_credentials_t <var class="var">cred</var>, const char * <var class="var">cafile</var>, gnutls_x509_crt_fmt_t <var class="var">type</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fcertificate_005fset_005fx509_005ftrust_005fdir">gnutls_certificate_set_x509_trust_dir</a> (gnutls_certificate_credentials_t <var class="var">cred</var>, const char * <var class="var">ca_dir</var>, gnutls_x509_crt_fmt_t <var class="var">type</var>)</code></dt>
</dl>

<p>The peer&rsquo;s certificate will be automatically verified if
<a class="ref" href="#gnutls_005fsession_005fset_005fverify_005fcert">gnutls_session_set_verify_cert</a> is called prior to handshake.
</p>
<p>Alternatively, one must set a callback function during the handshake
using <a class="ref" href="#gnutls_005fcertificate_005fset_005fverify_005ffunction">gnutls_certificate_set_verify_function</a>, which
will verify the peer&rsquo;s certificate once received. The verification
should happen using <a class="ref" href="#gnutls_005fcertificate_005fverify_005fpeers3">gnutls_certificate_verify_peers3</a> within
the callback. It will verify the certificate&rsquo;s signature and the owner
of the certificate. That will provide a brief verification output. If a
detailed output is required one should call <a class="ref" href="#gnutls_005fcertificate_005fget_005fpeers">gnutls_certificate_get_peers</a>
to obtain the raw certificate of the peer and verify it using the
functions discussed in <a class="ref" href="#X_002e509-certificates"><abbr class="acronym">X.509</abbr> certificates</a>.
</p>
<p>In both the automatic and the manual cases, the verification status returned
can be printed using <a class="ref" href="#gnutls_005fcertificate_005fverification_005fstatus_005fprint">gnutls_certificate_verification_status_print</a>.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsession_005fset_005fverify_005fcert"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_session_set_verify_cert</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, const char * <var class="var">hostname</var>, unsigned <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fsession_005fset_005fverify_005fcert"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a gnutls session
</p>
<p><var class="var">hostname</var>: is the expected name of the peer; may be <code class="code">NULL</code> 
</p>
<p><var class="var">flags</var>: flags for certificate verification &ndash; <code class="code">gnutls_certificate_verify_flags</code> 
</p>
<p>This function instructs GnuTLS to verify the peer&rsquo;s certificate
using the provided hostname. If the verification fails the handshake
will also fail with <code class="code">GNUTLS_E_CERTIFICATE_VERIFICATION_ERROR</code> . In that
case the verification result can be obtained using <code class="code">gnutls_session_get_verify_cert_status()</code> .
</p>
<p>The  <code class="code">hostname</code> pointer provided must remain valid for the lifetime
of the session. More precisely it should be available during any subsequent
handshakes. If no hostname is provided, no hostname verification
will be performed. For a more advanced verification function check
<code class="code">gnutls_session_set_verify_cert2()</code> .
</p>
<p>If  <code class="code">flags</code> is provided which contain a profile, this function should be
called after any session priority setting functions.
</p>
<p>The <code class="code">gnutls_session_set_verify_cert()</code>  function is intended to be used by TLS
clients to verify the server&rsquo;s certificate.
</p>
<p><strong class="strong">Since:</strong> 3.4.6
</p></dd></dl>

<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fcertificate_005fverify_005fpeers3">gnutls_certificate_verify_peers3</a> (gnutls_session_t <var class="var">session</var>, const char * <var class="var">hostname</var>, unsigned int * <var class="var">status</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fcertificate_005fset_005fverify_005ffunction">gnutls_certificate_set_verify_function</a> (gnutls_certificate_credentials_t <var class="var">cred</var>, gnutls_certificate_verify_function * <var class="var">func</var>)</code></dt>
</dl>

<p>Note that when using raw public-keys verification will not work because there is no corresponding
certificate body belonging to the raw key that can be verified. In that case the <a class="ref" href="#gnutls_005fcertificate_005fverify_005fpeers">gnutls_certificate_verify_peers</a>
family of functions will return a GNUTLS_E_INVALID_REQUEST error code. For authenticating raw public-keys
one must use an out-of-band mechanism, e.g. by comparing hashes or using trust on first use
(see <a class="ref" href="#Verifying-a-certificate-using-trust-on-first-use-authentication">Verifying a certificate using trust on first use authentication</a>).
</p>

<hr>
</div>
<div class="subsection-level-extent" id="Raw-public_002dkey-credentials">
<div class="nav-panel">
<p>
Next: <a href="#SRP-credentials" accesskey="n" rel="next">SRP</a>, Previous: <a href="#Certificate-credentials" accesskey="p" rel="prev">Certificates</a>, Up: <a href="#Associating-the-credentials" accesskey="u" rel="up">Associating the credentials</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Raw-public_002dkeys-2"><span>6.4.2 Raw public-keys<a class="copiable-link" href="#Raw-public_002dkeys-2"> &para;</a></span></h4>
<p>As of version 3.6.6 GnuTLS supports <a class="ref" href="#Raw-public_002dkeys">Raw public-keys</a>. With raw public-keys only the
public-key part (that is normally embedded in a certificate) is transmitted to the peer.
In order to load a raw public-key and its corresponding private key in a credentials
structure one can use the following functions.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fcertificate_005fset_005fkey">gnutls_certificate_set_key</a> (gnutls_certificate_credentials_t <var class="var">res</var>, const char ** <var class="var">names</var>, int <var class="var">names_size</var>, gnutls_pcert_st * <var class="var">pcert_list</var>, int <var class="var">pcert_list_size</var>, gnutls_privkey_t <var class="var">key</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fcertificate_005fset_005frawpk_005fkey_005fmem">gnutls_certificate_set_rawpk_key_mem</a> (gnutls_certificate_credentials_t <var class="var">cred</var>, const gnutls_datum_t * <var class="var">spki</var>, const gnutls_datum_t * <var class="var">pkey</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, const char * <var class="var">pass</var>, unsigned int <var class="var">key_usage</var>, const char ** <var class="var">names</var>, unsigned int <var class="var">names_length</var>, unsigned int <var class="var">flags</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fcertificate_005fset_005frawpk_005fkey_005ffile">gnutls_certificate_set_rawpk_key_file</a> (gnutls_certificate_credentials_t <var class="var">cred</var>, const char * <var class="var">rawpkfile</var>, const char * <var class="var">privkeyfile</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, const char * <var class="var">pass</var>, unsigned int <var class="var">key_usage</var>, const char ** <var class="var">names</var>, unsigned int <var class="var">names_length</var>, unsigned int <var class="var">privkey_flags</var>, unsigned int <var class="var">pkcs11_flags</var>)</code></dt>
</dl>


<hr>
</div>
<div class="subsection-level-extent" id="SRP-credentials">
<div class="nav-panel">
<p>
Next: <a href="#PSK-credentials" accesskey="n" rel="next">PSK</a>, Previous: <a href="#Raw-public_002dkey-credentials" accesskey="p" rel="prev">Raw public-keys</a>, Up: <a href="#Associating-the-credentials" accesskey="u" rel="up">Associating the credentials</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="SRP"><span>6.4.3 SRP<a class="copiable-link" href="#SRP"> &para;</a></span></h4>

<p>The initialization functions in SRP credentials differ between
client and server.
Clients supporting <abbr class="acronym">SRP</abbr> should set the username and password
prior to connection, to the credentials structure.
Alternatively <a class="ref" href="#gnutls_005fsrp_005fset_005fclient_005fcredentials_005ffunction">gnutls_srp_set_client_credentials_function</a>
may be used instead, to specify a callback function that should return the
SRP username and password.
The callback is called once during the <abbr class="acronym">TLS</abbr> handshake.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fsrp_005fallocate_005fserver_005fcredentials">gnutls_srp_allocate_server_credentials</a> (gnutls_srp_server_credentials_t * <var class="var">sc</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fsrp_005fallocate_005fclient_005fcredentials">gnutls_srp_allocate_client_credentials</a> (gnutls_srp_client_credentials_t * <var class="var">sc</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fsrp_005ffree_005fserver_005fcredentials">gnutls_srp_free_server_credentials</a> (gnutls_srp_server_credentials_t <var class="var">sc</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fsrp_005ffree_005fclient_005fcredentials">gnutls_srp_free_client_credentials</a> (gnutls_srp_client_credentials_t <var class="var">sc</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fsrp_005fset_005fclient_005fcredentials">gnutls_srp_set_client_credentials</a> (gnutls_srp_client_credentials_t <var class="var">res</var>, const char * <var class="var">username</var>, const char * <var class="var">password</var>)</code></dt>
</dl>





<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsrp_005fset_005fclient_005fcredentials_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_srp_set_client_credentials_function</strong> <code class="def-code-arguments">(gnutls_srp_client_credentials_t <var class="var">cred</var>, gnutls_srp_client_credentials_function * <var class="var">func</var>)</code><a class="copiable-link" href="#index-gnutls_005fsrp_005fset_005fclient_005fcredentials_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">cred</var>: is a <code class="code">gnutls_srp_server_credentials_t</code>  type.
</p>
<p><var class="var">func</var>: is the callback function
</p>
<p>This function can be used to set a callback to retrieve the
username and password for client SRP authentication.  The
callback&rsquo;s function form is:
</p>
<p>int (*callback)(gnutls_session_t, char** username, char**password);
</p>
<p>The  <code class="code">username</code> and  <code class="code">password</code> must be allocated using
<code class="code">gnutls_malloc()</code> .
</p>
<p>The  <code class="code">username</code> should be an ASCII string or UTF-8
string. In case of a UTF-8 string it is recommended to be following
the PRECIS framework for usernames (rfc8265). The password can
be in ASCII format, or normalized using <code class="code">gnutls_utf8_password_normalize()</code> .
</p>
<p>The callback function will be called once per handshake before the
initial hello message is sent.
</p>
<p>The callback should not return a negative error code the second
time called, since the handshake procedure will be aborted.
</p>
<p>The callback function should return 0 on success.
-1 indicates an error.
</p></dd></dl>

<p>In server side the default behavior of <abbr class="acronym">GnuTLS</abbr> is to read
the usernames and <abbr class="acronym">SRP</abbr> verifiers from password files. These
password file format is compatible the with the <em class="emph">Stanford srp libraries</em>
format.  If a different password file format is to be used, then
<a class="ref" href="#gnutls_005fsrp_005fset_005fserver_005fcredentials_005ffunction">gnutls_srp_set_server_credentials_function</a> should be called,
to set an appropriate callback.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsrp_005fset_005fserver_005fcredentials_005ffile"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_srp_set_server_credentials_file</strong> <code class="def-code-arguments">(gnutls_srp_server_credentials_t <var class="var">res</var>, const char * <var class="var">password_file</var>, const char * <var class="var">password_conf_file</var>)</code><a class="copiable-link" href="#index-gnutls_005fsrp_005fset_005fserver_005fcredentials_005ffile"> &para;</a></span></dt>
<dd><p><var class="var">res</var>: is a <code class="code">gnutls_srp_server_credentials_t</code>  type.
</p>
<p><var class="var">password_file</var>: is the SRP password file (tpasswd)
</p>
<p><var class="var">password_conf_file</var>: is the SRP password conf file (tpasswd.conf)
</p>
<p>This function sets the password files, in a
<code class="code">gnutls_srp_server_credentials_t</code>  type.  Those password files
hold usernames and verifiers and will be used for SRP
authentication.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, or an
error code.
</p></dd></dl>





<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsrp_005fset_005fserver_005fcredentials_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_srp_set_server_credentials_function</strong> <code class="def-code-arguments">(gnutls_srp_server_credentials_t <var class="var">cred</var>, gnutls_srp_server_credentials_function * <var class="var">func</var>)</code><a class="copiable-link" href="#index-gnutls_005fsrp_005fset_005fserver_005fcredentials_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">cred</var>: is a <code class="code">gnutls_srp_server_credentials_t</code>  type.
</p>
<p><var class="var">func</var>: is the callback function
</p>
<p>This function can be used to set a callback to retrieve the user&rsquo;s
SRP credentials.  The callback&rsquo;s function form is:
</p>
<p>int (*callback)(gnutls_session_t, const char* username,
gnutls_datum_t *salt, gnutls_datum_t *verifier, gnutls_datum_t *generator,
gnutls_datum_t *prime);
</p>
<p><code class="code">username</code> contains the actual username.
The  <code class="code">salt</code> ,  <code class="code">verifier</code> ,  <code class="code">generator</code> and  <code class="code">prime</code> must be filled
in using the <code class="code">gnutls_malloc()</code> . For convenience  <code class="code">prime</code> and  <code class="code">generator</code> may also be one of the static parameters defined in gnutls.h.
</p>
<p>Initially, the data field is NULL in every <code class="code">gnutls_datum_t</code> 
structure that the callback has to fill in. When the
callback is done GnuTLS deallocates all of those buffers
which are non-NULL, regardless of the return value.
</p>
<p>In order to prevent attackers from guessing valid usernames,
if a user does not exist, g and n values should be filled in
using a random user&rsquo;s parameters. In that case the callback must
return the special value (1).
See <code class="code">gnutls_srp_set_server_fake_salt_seed</code>  too.
If this is not required for your application, return a negative
number from the callback to abort the handshake.
</p>
<p>The callback function will only be called once per handshake.
The callback function should return 0 on success, while
-1 indicates an error.
</p></dd></dl>


<hr>
</div>
<div class="subsection-level-extent" id="PSK-credentials">
<div class="nav-panel">
<p>
Next: <a href="#Anonymous-credentials" accesskey="n" rel="next">Anonymous</a>, Previous: <a href="#SRP-credentials" accesskey="p" rel="prev">SRP</a>, Up: <a href="#Associating-the-credentials" accesskey="u" rel="up">Associating the credentials</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="PSK"><span>6.4.4 PSK<a class="copiable-link" href="#PSK"> &para;</a></span></h4>
<p>The initialization functions in PSK credentials differ between
client and server.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpsk_005fallocate_005fserver_005fcredentials">gnutls_psk_allocate_server_credentials</a> (gnutls_psk_server_credentials_t * <var class="var">sc</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpsk_005fallocate_005fclient_005fcredentials">gnutls_psk_allocate_client_credentials</a> (gnutls_psk_client_credentials_t * <var class="var">sc</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fpsk_005ffree_005fserver_005fcredentials">gnutls_psk_free_server_credentials</a> (gnutls_psk_server_credentials_t <var class="var">sc</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fpsk_005ffree_005fclient_005fcredentials">gnutls_psk_free_client_credentials</a> (gnutls_psk_client_credentials_t <var class="var">sc</var>)</code></dt>
</dl>

<p>Clients supporting <abbr class="acronym">PSK</abbr> should supply the username and key
before a TLS session is established.  Alternatively
<a class="ref" href="#gnutls_005fpsk_005fset_005fclient_005fcredentials_005ffunction">gnutls_psk_set_client_credentials_function</a> can be used to
specify a callback function. This has the
advantage that the callback will be called only if <abbr class="acronym">PSK</abbr> has
been negotiated.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpsk_005fset_005fclient_005fcredentials">gnutls_psk_set_client_credentials</a> (gnutls_psk_client_credentials_t <var class="var">res</var>, const char * <var class="var">username</var>, const gnutls_datum_t * <var class="var">key</var>, gnutls_psk_key_flags <var class="var">flags</var>)</code></dt>
</dl>





<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpsk_005fset_005fclient_005fcredentials_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_psk_set_client_credentials_function</strong> <code class="def-code-arguments">(gnutls_psk_client_credentials_t <var class="var">cred</var>, gnutls_psk_client_credentials_function * <var class="var">func</var>)</code><a class="copiable-link" href="#index-gnutls_005fpsk_005fset_005fclient_005fcredentials_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">cred</var>: is a <code class="code">gnutls_psk_server_credentials_t</code>  type.
</p>
<p><var class="var">func</var>: is the callback function
</p>
<p>This function can be used to set a callback to retrieve the username and
password for client PSK authentication.
The callback&rsquo;s function form is:
int (*callback)(gnutls_session_t, char** username,
gnutls_datum_t* key);
</p>
<p>The  <code class="code">username</code> and  <code class="code">key</code> -&gt;data must be allocated using <code class="code">gnutls_malloc()</code> .
The  <code class="code">username</code> should be an ASCII string or UTF-8
string. In case of a UTF-8 string it is recommended to be following
the PRECIS framework for usernames (rfc8265).
</p>
<p>The callback function will be called once per handshake.
</p>
<p>The callback function should return 0 on success.
-1 indicates an error.
</p></dd></dl>

<p>In server side the default behavior of <abbr class="acronym">GnuTLS</abbr> is to read
the usernames and <abbr class="acronym">PSK</abbr> keys from a password file. The
password file should contain usernames and keys in hexadecimal
format. The name of the password file can be stored to the credentials
structure by calling <a class="ref" href="#gnutls_005fpsk_005fset_005fserver_005fcredentials_005ffile">gnutls_psk_set_server_credentials_file</a>.  If
a different password file format is to be used, then
a callback should be set instead by <a class="ref" href="#gnutls_005fpsk_005fset_005fserver_005fcredentials_005ffunction">gnutls_psk_set_server_credentials_function</a>.
</p>
<p>The server can help the client chose a suitable username and password,
by sending a hint. Note that there is no common profile for the PSK hint and applications
are discouraged to use it.
A server, may specify the hint by calling
<a class="ref" href="#gnutls_005fpsk_005fset_005fserver_005fcredentials_005fhint">gnutls_psk_set_server_credentials_hint</a>.  The client can retrieve
the hint, for example in the callback function, using
<a class="ref" href="#gnutls_005fpsk_005fclient_005fget_005fhint">gnutls_psk_client_get_hint</a>.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpsk_005fset_005fserver_005fcredentials_005ffile"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_psk_set_server_credentials_file</strong> <code class="def-code-arguments">(gnutls_psk_server_credentials_t <var class="var">res</var>, const char * <var class="var">password_file</var>)</code><a class="copiable-link" href="#index-gnutls_005fpsk_005fset_005fserver_005fcredentials_005ffile"> &para;</a></span></dt>
<dd><p><var class="var">res</var>: is a <code class="code">gnutls_psk_server_credentials_t</code>  type.
</p>
<p><var class="var">password_file</var>: is the PSK password file (passwd.psk)
</p>
<p>This function sets the password file, in a
<code class="code">gnutls_psk_server_credentials_t</code>  type.  This password file
holds usernames and keys and will be used for PSK authentication.
</p>
<p>Each entry in the file consists of a username, followed by a colon
(&rsquo;:&rsquo;) and a hex-encoded key.  If the username contains a colon or
any other special character, it can be hex-encoded preceded by a
&rsquo;#&rsquo;.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise
an error code is returned.
</p></dd></dl>

<dl class="table">
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fpsk_005fset_005fserver_005fcredentials_005ffunction">gnutls_psk_set_server_credentials_function</a> (gnutls_psk_server_credentials_t <var class="var">cred</var>, gnutls_psk_server_credentials_function * <var class="var">func</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpsk_005fset_005fserver_005fcredentials_005fhint">gnutls_psk_set_server_credentials_hint</a> (gnutls_psk_server_credentials_t <var class="var">res</var>, const char * <var class="var">hint</var>)</code></dt>
<dt><code class="code"><var class="var">const char *</var> <a class="ref" href="#gnutls_005fpsk_005fclient_005fget_005fhint">gnutls_psk_client_get_hint</a> (gnutls_session_t <var class="var">session</var>)</code></dt>
</dl>

<hr>
</div>
<div class="subsection-level-extent" id="Anonymous-credentials">
<div class="nav-panel">
<p>
Previous: <a href="#PSK-credentials" accesskey="p" rel="prev">PSK</a>, Up: <a href="#Associating-the-credentials" accesskey="u" rel="up">Associating the credentials</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Anonymous"><span>6.4.5 Anonymous<a class="copiable-link" href="#Anonymous"> &para;</a></span></h4>
<p>The key exchange methods for anonymous authentication
since GnuTLS 3.6.0 will utilize the RFC7919 parameters, unless
explicit parameters have been provided and associated with an
anonymous credentials structure. Check <a class="ref" href="#Parameter-generation">Parameter generation</a> for more information.
The initialization functions for the credentials are shown below.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fanon_005fallocate_005fserver_005fcredentials">gnutls_anon_allocate_server_credentials</a> (gnutls_anon_server_credentials_t * <var class="var">sc</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fanon_005fallocate_005fclient_005fcredentials">gnutls_anon_allocate_client_credentials</a> (gnutls_anon_client_credentials_t * <var class="var">sc</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fanon_005ffree_005fserver_005fcredentials">gnutls_anon_free_server_credentials</a> (gnutls_anon_server_credentials_t <var class="var">sc</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fanon_005ffree_005fclient_005fcredentials">gnutls_anon_free_client_credentials</a> (gnutls_anon_client_credentials_t <var class="var">sc</var>)</code></dt>
</dl>



<hr>
</div>
</div>
<div class="section-level-extent" id="Setting-up-the-transport-layer">
<div class="nav-panel">
<p>
Next: <a href="#TLS-handshake" accesskey="n" rel="next">TLS handshake</a>, Previous: <a href="#Associating-the-credentials" accesskey="p" rel="prev">Associating the credentials</a>, Up: <a href="#How-to-use-GnuTLS-in-applications" accesskey="u" rel="up">How to use <abbr class="acronym">GnuTLS</abbr> in applications</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Setting-up-the-transport-layer-1"><span>6.5 Setting up the transport layer<a class="copiable-link" href="#Setting-up-the-transport-layer-1"> &para;</a></span></h3>

<p>The next step is to setup the underlying transport layer details. The
Berkeley sockets are implicitly used by GnuTLS, thus a
call to <a class="ref" href="#gnutls_005ftransport_005fset_005fint">gnutls_transport_set_int</a> would be sufficient to
specify the socket descriptor.
</p>
<dl class="table">
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005ftransport_005fset_005fint">gnutls_transport_set_int</a> (gnutls_session_t <var class="var">session</var>, int <var class="var">fd</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005ftransport_005fset_005fint2">gnutls_transport_set_int2</a> (gnutls_session_t <var class="var">session</var>, int <var class="var">recv_fd</var>, int <var class="var">send_fd</var>)</code></dt>
</dl>

<p>If however another transport layer than TCP is selected, then
a pointer should be used instead to express the parameter to be
passed to custom functions. In that case the following functions should
be used instead.
</p>
<dl class="table">
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005ftransport_005fset_005fptr">gnutls_transport_set_ptr</a> (gnutls_session_t <var class="var">session</var>, gnutls_transport_ptr_t <var class="var">ptr</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005ftransport_005fset_005fptr2">gnutls_transport_set_ptr2</a> (gnutls_session_t <var class="var">session</var>, gnutls_transport_ptr_t <var class="var">recv_ptr</var>, gnutls_transport_ptr_t <var class="var">send_ptr</var>)</code></dt>
</dl>

<p>Moreover all of the following push and pull callbacks should be set.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ftransport_005fset_005fpush_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_transport_set_push_function</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_push_func <var class="var">push_func</var>)</code><a class="copiable-link" href="#index-gnutls_005ftransport_005fset_005fpush_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">push_func</var>: a callback function similar to <code class="code">write()</code> 
</p>
<p>This is the function where you set a push function for gnutls to
use in order to send data.  If you are going to use berkeley style
sockets, you do not need to use this function since the default
send(2) will probably be ok.  Otherwise you should specify this
function for gnutls to be able to send data.
The callback should return a positive number indicating the
bytes sent, and -1 on error.
</p>
<p><code class="code">push_func</code> is of the form,
ssize_t (*gnutls_push_func)(gnutls_transport_ptr_t, const void*, size_t);
</p></dd></dl>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ftransport_005fset_005fvec_005fpush_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_transport_set_vec_push_function</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_vec_push_func <var class="var">vec_func</var>)</code><a class="copiable-link" href="#index-gnutls_005ftransport_005fset_005fvec_005fpush_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">vec_func</var>: a callback function similar to <code class="code">writev()</code> 
</p>
<p>Using this function you can override the default writev(2)
function for gnutls to send data. Setting this callback 
instead of <code class="code">gnutls_transport_set_push_function()</code>  is recommended
since it introduces less overhead in the TLS handshake process.
</p>
<p><code class="code">vec_func</code> is of the form,
ssize_t (*gnutls_vec_push_func) (gnutls_transport_ptr_t, const giovec_t * iov, int iovcnt);
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ftransport_005fset_005fpull_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_transport_set_pull_function</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_pull_func <var class="var">pull_func</var>)</code><a class="copiable-link" href="#index-gnutls_005ftransport_005fset_005fpull_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">pull_func</var>: a callback function similar to <code class="code">read()</code> 
</p>
<p>This is the function where you set a function for gnutls to receive
data.  Normally, if you use berkeley style sockets, do not need to
use this function since the default recv(2) will probably be ok.
The callback should return 0 on connection termination, a positive
number indicating the number of bytes received, and -1 on error.
</p>
<p><code class="code">gnutls_pull_func</code> is of the form,
ssize_t (*gnutls_pull_func)(gnutls_transport_ptr_t, void*, size_t);
</p></dd></dl>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ftransport_005fset_005fpull_005ftimeout_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_transport_set_pull_timeout_function</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_pull_timeout_func <var class="var">func</var>)</code><a class="copiable-link" href="#index-gnutls_005ftransport_005fset_005fpull_005ftimeout_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">func</var>: a callback function
</p>
<p>This is the function where you set a function for gnutls to know
whether data are ready to be received. It should wait for data a
given time frame in milliseconds. The callback should return 0 on 
timeout, a positive number if data can be received, and -1 on error.
You&rsquo;ll need to override this function if <code class="code">select()</code>  is not suitable
for the provided transport calls.
</p>
<p>As with <code class="code">select()</code> , if the timeout value is zero the callback should return
zero if no data are immediately available. The special value
<code class="code">GNUTLS_INDEFINITE_TIMEOUT</code>  indicates that the callback should wait indefinitely
for data.
</p>
<p><code class="code">gnutls_pull_timeout_func</code> is of the form,
int (*gnutls_pull_timeout_func)(gnutls_transport_ptr_t, unsigned int ms);
</p>
<p>This callback is necessary when <code class="code">gnutls_handshake_set_timeout()</code>  or 
<code class="code">gnutls_record_set_timeout()</code>  are set, under TLS1.3 and for enforcing the DTLS
mode timeouts when in blocking mode.
</p>
<p>For compatibility with future GnuTLS versions this callback must be set when
a custom pull function is registered. The callback will not be used when the
session is in TLS mode with non-blocking sockets. That is, when <code class="code">GNUTLS_NONBLOCK</code> 
is specified for a TLS session in <code class="code">gnutls_init()</code> .
</p>
<p>The helper function <code class="code">gnutls_system_recv_timeout()</code>  is provided to
simplify writing callbacks. 
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>


<p>The functions above accept a callback function which
should return the number of bytes written, or -1 on
error and should set <code class="code">errno</code> appropriately.
In some environments, setting <code class="code">errno</code> is unreliable. For example
Windows have several errno variables in different CRTs, or in other
systems it may be a non thread-local variable.  If this is a concern to
you, call <a class="ref" href="#gnutls_005ftransport_005fset_005ferrno">gnutls_transport_set_errno</a> with the intended errno
value instead of setting <code class="code">errno</code> directly.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ftransport_005fset_005ferrno"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_transport_set_errno</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, int <var class="var">err</var>)</code><a class="copiable-link" href="#index-gnutls_005ftransport_005fset_005ferrno"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">err</var>: error value to store in session-specific errno variable.
</p>
<p>Store  <code class="code">err</code> in the session-specific errno variable.  Useful values
for  <code class="code">err</code> are EINTR, EAGAIN and EMSGSIZE, other values are treated will be
treated as real errors in the push/pull function.
</p>
<p>This function is useful in replacement push and pull functions set by
<code class="code">gnutls_transport_set_push_function()</code>  and
<code class="code">gnutls_transport_set_pull_function()</code>  under Windows, where the
replacements may not have access to the same  <code class="code">errno</code> variable that is used by GnuTLS (e.g., the application is linked to
msvcr71.dll and gnutls is linked to msvcrt.dll).
</p>
<p>This function is unreliable if you are using the same
 <code class="code">session</code> in different threads for sending and receiving.
</p></dd></dl>

<p><abbr class="acronym">GnuTLS</abbr> currently only interprets the EINTR, EAGAIN and EMSGSIZE errno
values and returns the corresponding <abbr class="acronym">GnuTLS</abbr> error codes:
</p><ul class="itemize mark-bullet">
<li><code class="code">GNUTLS_E_INTERRUPTED</code>
</li><li><code class="code">GNUTLS_E_AGAIN</code>
</li><li><code class="code">GNUTLS_E_LARGE_PACKET</code>
</li></ul>
<p>The EINTR and EAGAIN values are returned by interrupted system calls,
or when non blocking IO is used.  All <abbr class="acronym">GnuTLS</abbr> functions can be
resumed (called again), if any of the above error codes is returned. The
EMSGSIZE value is returned when attempting to send a large datagram.
</p>
<p>In the case of DTLS it is also desirable to override the generic
transport functions with functions that emulate the operation
of <code class="code">recvfrom</code> and <code class="code">sendto</code>. In addition
<abbr class="acronym">DTLS</abbr> requires timers during the receive of a handshake
message, set using the <a class="ref" href="#gnutls_005ftransport_005fset_005fpull_005ftimeout_005ffunction">gnutls_transport_set_pull_timeout_function</a>
function. To check the retransmission timers the function
<a class="ref" href="#gnutls_005fdtls_005fget_005ftimeout">gnutls_dtls_get_timeout</a> is provided, which returns the time
remaining until the next retransmission, or better the time until
<a class="ref" href="#gnutls_005fhandshake">gnutls_handshake</a> should be called again.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ftransport_005fset_005fpull_005ftimeout_005ffunction-1"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_transport_set_pull_timeout_function</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_pull_timeout_func <var class="var">func</var>)</code><a class="copiable-link" href="#index-gnutls_005ftransport_005fset_005fpull_005ftimeout_005ffunction-1"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">func</var>: a callback function
</p>
<p>This is the function where you set a function for gnutls to know
whether data are ready to be received. It should wait for data a
given time frame in milliseconds. The callback should return 0 on 
timeout, a positive number if data can be received, and -1 on error.
You&rsquo;ll need to override this function if <code class="code">select()</code>  is not suitable
for the provided transport calls.
</p>
<p>As with <code class="code">select()</code> , if the timeout value is zero the callback should return
zero if no data are immediately available. The special value
<code class="code">GNUTLS_INDEFINITE_TIMEOUT</code>  indicates that the callback should wait indefinitely
for data.
</p>
<p><code class="code">gnutls_pull_timeout_func</code> is of the form,
int (*gnutls_pull_timeout_func)(gnutls_transport_ptr_t, unsigned int ms);
</p>
<p>This callback is necessary when <code class="code">gnutls_handshake_set_timeout()</code>  or 
<code class="code">gnutls_record_set_timeout()</code>  are set, under TLS1.3 and for enforcing the DTLS
mode timeouts when in blocking mode.
</p>
<p>For compatibility with future GnuTLS versions this callback must be set when
a custom pull function is registered. The callback will not be used when the
session is in TLS mode with non-blocking sockets. That is, when <code class="code">GNUTLS_NONBLOCK</code> 
is specified for a TLS session in <code class="code">gnutls_init()</code> .
</p>
<p>The helper function <code class="code">gnutls_system_recv_timeout()</code>  is provided to
simplify writing callbacks. 
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdtls_005fget_005ftimeout"><span class="category-def">Function: </span><span><code class="def-type">unsigned int</code> <strong class="def-name">gnutls_dtls_get_timeout</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fdtls_005fget_005ftimeout"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>This function will return the milliseconds remaining
for a retransmission of the previously sent handshake
message. This function is useful when DTLS is used in
non-blocking mode, to estimate when to call <code class="code">gnutls_handshake()</code> 
if no packets have been received.
</p>
<p><strong class="strong">Returns:</strong> the remaining time in milliseconds.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>


<ul class="mini-toc">
<li><a href="#Asynchronous-operation" accesskey="1">Asynchronous operation</a></li>
<li><a href="#Reducing-round_002dtrips" accesskey="2">Reducing round-trips</a></li>
<li><a href="#Zero_002droundtrip-mode" accesskey="3">Zero-roundtrip mode</a></li>
<li><a href="#Anti_002dreplay-protection" accesskey="4">Anti-replay protection</a></li>
<li><a href="#DTLS-sessions" accesskey="5">DTLS sessions</a></li>
<li><a href="#DTLS-and-SCTP" accesskey="6">DTLS and SCTP</a></li>
</ul>
<hr>
<div class="subsection-level-extent" id="Asynchronous-operation">
<div class="nav-panel">
<p>
Next: <a href="#Reducing-round_002dtrips" accesskey="n" rel="next">Reducing round-trips</a>, Up: <a href="#Setting-up-the-transport-layer" accesskey="u" rel="up">Setting up the transport layer</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Asynchronous-operation-1"><span>6.5.1 Asynchronous operation<a class="copiable-link" href="#Asynchronous-operation-1"> &para;</a></span></h4>

<p><abbr class="acronym">GnuTLS</abbr> can be used with asynchronous socket or event-driven programming.
The approach is similar to using Berkeley sockets under such an environment.
The blocking, due to network interaction, calls such as
<a class="ref" href="#gnutls_005fhandshake">gnutls_handshake</a>, <a class="ref" href="#gnutls_005frecord_005frecv">gnutls_record_recv</a>,
can be set to non-blocking by setting the underlying sockets to non-blocking.
If other push and pull functions are setup, then they should behave the same
way as <code class="code">recv</code> and <code class="code">send</code> when used in a non-blocking
way, i.e., return -1 and set errno to <code class="code">EAGAIN</code>. Since, during a TLS protocol session
<abbr class="acronym">GnuTLS</abbr> does not block except for network interaction, the non blocking
<code class="code">EAGAIN</code> errno will be propagated and <abbr class="acronym">GnuTLS</abbr> functions
will return the <code class="code">GNUTLS_E_AGAIN</code> error code. Such calls can be resumed the
same way as a system call would.
The only exception is <a class="ref" href="#gnutls_005frecord_005fsend">gnutls_record_send</a>,
which if interrupted subsequent calls need not to include the data to be
sent (can be called with NULL argument).
</p>
<p>When using the <code class="code">poll</code> or <code class="code">select</code> system calls though, one should remember
that they only apply to the kernel sockets API. To check for any
available buffered data in a <abbr class="acronym">GnuTLS</abbr> session,
utilize <a class="ref" href="#gnutls_005frecord_005fcheck_005fpending">gnutls_record_check_pending</a>,
either before the <code class="code">poll</code> system call, or after a call to
<a class="ref" href="#gnutls_005frecord_005frecv">gnutls_record_recv</a>. Data queued by <a class="ref" href="#gnutls_005frecord_005fsend">gnutls_record_send</a>
(when interrupted) can be discarded using <a class="ref" href="#gnutls_005frecord_005fdiscard_005fqueued">gnutls_record_discard_queued</a>.
</p>
<p>An example of GnuTLS&rsquo; usage with asynchronous operation can be found
in <code class="code">doc/examples/tlsproxy</code>.
</p>
<p>The following paragraphs describe the detailed requirements for non-blocking
operation when using the TLS or DTLS protocols.
</p>
<ul class="mini-toc">
<li><a href="#TLS-protocol" accesskey="1">TLS protocol</a></li>
<li><a href="#Datagram-TLS-protocol" accesskey="2">Datagram TLS protocol</a></li>
</ul>
<div class="subsubsection-level-extent" id="TLS-protocol">
<h4 class="subsubsection"><span>6.5.1.1 TLS protocol<a class="copiable-link" href="#TLS-protocol"> &para;</a></span></h4>
<p>There are no special requirements for the TLS protocol operation in non-blocking
mode if a non-blocking socket is used.
</p>
<p>It is recommended, however, for future compatibility, when in non-blocking mode, to
call the <a class="ref" href="#gnutls_005finit">gnutls_init</a> function with the
<code class="code">GNUTLS_NONBLOCK</code> flag set (see <a class="ref" href="#Session-initialization">Session initialization</a>).
</p>
</div>
<div class="subsubsection-level-extent" id="Datagram-TLS-protocol">
<h4 class="subsubsection"><span>6.5.1.2 Datagram TLS protocol<a class="copiable-link" href="#Datagram-TLS-protocol"> &para;</a></span></h4>
<p>When in non-blocking mode the function, the <a class="ref" href="#gnutls_005finit">gnutls_init</a> function
must be called with the <code class="code">GNUTLS_NONBLOCK</code> flag set (see <a class="ref" href="#Session-initialization">Session initialization</a>).
</p>
<p>In contrast with the TLS protocol, the pull timeout function is required,
but will only be called with a timeout of zero. In that case it should indicate
whether there are data to be received or not. When not using the default pull function,
then <a class="ref" href="#gnutls_005ftransport_005fset_005fpull_005ftimeout_005ffunction">gnutls_transport_set_pull_timeout_function</a> should be called.
</p>
<p>Although in the TLS protocol implementation each call to receive or send
function implies to restoring the same function that was interrupted, in
the DTLS protocol this requirement isn&rsquo;t true.
There are cases where a retransmission is required, which are indicated by
a received message and thus <a class="ref" href="#gnutls_005frecord_005fget_005fdirection">gnutls_record_get_direction</a> must be called
to decide which direction to check prior to restoring a function call.
</p>



<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frecord_005fget_005fdirection"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_record_get_direction</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005frecord_005fget_005fdirection"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>This function is useful to determine whether a GnuTLS function was interrupted
while sending or receiving, so that <code class="code">select()</code>  or <code class="code">poll()</code>  may be called appropriately.
</p>
<p>It provides information about the internals of the record
protocol and is only useful if a prior gnutls function call,
e.g.  <code class="code">gnutls_handshake()</code> , was interrupted and returned
<code class="code">GNUTLS_E_INTERRUPTED</code>  or <code class="code">GNUTLS_E_AGAIN</code> . After such an interrupt
applications may call <code class="code">select()</code>  or <code class="code">poll()</code>  before restoring the
interrupted GnuTLS function.
</p>
<p>This function&rsquo;s output is unreliable if you are using the same
 <code class="code">session</code> in different threads for sending and receiving.
</p>
<p><strong class="strong">Returns:</strong> 0 if interrupted while trying to read data, or 1 while trying to write data.
</p></dd></dl>

<p>When calling <a class="ref" href="#gnutls_005fhandshake">gnutls_handshake</a> through a multi-plexer,
to be able to handle properly the DTLS handshake retransmission timers,
the function <a class="ref" href="#gnutls_005fdtls_005fget_005ftimeout">gnutls_dtls_get_timeout</a>
should be used to estimate when to call <a class="ref" href="#gnutls_005fhandshake">gnutls_handshake</a> if
no data have been received.
</p>
<hr>
</div>
</div>
<div class="subsection-level-extent" id="Reducing-round_002dtrips">
<div class="nav-panel">
<p>
Next: <a href="#Zero_002droundtrip-mode" accesskey="n" rel="next">Zero-roundtrip mode</a>, Previous: <a href="#Asynchronous-operation" accesskey="p" rel="prev">Asynchronous operation</a>, Up: <a href="#Setting-up-the-transport-layer" accesskey="u" rel="up">Setting up the transport layer</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Reducing-round_002dtrips-1"><span>6.5.2 Reducing round-trips<a class="copiable-link" href="#Reducing-round_002dtrips-1"> &para;</a></span></h4>

<p>The full TLS 1.2 handshake requires 2 round-trips to complete, and when
combined with TCP&rsquo;s SYN and SYN-ACK negotiation it extends to 3 full
round-trips. While, TLS 1.3 reduces that to two round-trips when under TCP,
it still adds considerable latency, making the protocol unsuitable for
certain applications.
</p>
<p>To optimize the handshake latency, in client side, it is possible to take
advantage of the TCP fast open [<a class="ref" href="#RFC7413">RFC7413</a>] mechanism on operating
systems that support it. That can be done either by manually crafting the push and pull
callbacks, or by utilizing <a class="ref" href="#gnutls_005ftransport_005fset_005ffastopen">gnutls_transport_set_fastopen</a>. In that
case the initial TCP handshake is eliminated, reducing the TLS 1.2 handshake round-trip
to 2, and the TLS 1.3 handshake to a single round-trip.
Note, that when this function is used, any connection failures will be reported during the
<a class="ref" href="#gnutls_005fhandshake">gnutls_handshake</a> function call with error code <code class="code">GNUTLS_E_PUSH_ERROR</code>.
</p>



<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ftransport_005fset_005ffastopen"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_transport_set_fastopen</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, int <var class="var">fd</var>, struct sockaddr * <var class="var">connect_addr</var>, socklen_t <var class="var">connect_addrlen</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005ftransport_005fset_005ffastopen"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">fd</var>: is the session&rsquo;s socket descriptor
</p>
<p><var class="var">connect_addr</var>: is the address we want to connect to
</p>
<p><var class="var">connect_addrlen</var>: is the length of  <code class="code">connect_addr</code> 
</p>
<p><var class="var">flags</var>: must be zero
</p>
<p>Enables TCP Fast Open (TFO) for the specified TLS client session.
That means that TCP connection establishment and the transmission
of the first TLS client hello packet are combined. The
peer&rsquo;s address must be  specified in  <code class="code">connect_addr</code> and  <code class="code">connect_addrlen</code> ,
and the socket specified by  <code class="code">fd</code> should not be connected.
</p>
<p>TFO only works for TCP sockets of type AF_INET and AF_INET6.
If the OS doesn&rsquo;t support TCP fast open this function will result
to gnutls using <code class="code">connect()</code>  transparently during the first write.
</p>
<p><strong class="strong">Note:</strong> This function overrides all the transport callback functions.
If this is undesirable, TCP Fast Open must be implemented on the user
callback functions without calling this function. When using
this function, transport callbacks must not be set, and 
<code class="code">gnutls_transport_set_ptr()</code>  or <code class="code">gnutls_transport_set_int()</code> 
must not be called.
</p>
<p>On GNU/Linux TFO has to be enabled at the system layer, that is
in /proc/sys/net/ipv4/tcp_fastopen, bit 0 has to be set.
</p>
<p>This function has no effect on server sessions.
</p>
<p><strong class="strong">Since:</strong> 3.5.3
</p></dd></dl>

<p>When restricted to TLS 1.2, and non-resumed sessions, it is possible to further
reduce the round-trips to a single one by taking advantage of the <a class="ref" href="#False-Start">False Start</a>
TLS extension. This can be enabled by setting the <abbr class="acronym">GNUTLS_ENABLE_FALSE_START</abbr>
flag on <a class="ref" href="#gnutls_005finit">gnutls_init</a>.
</p>
<p>Under TLS 1.3, the server side can start transmitting before the handshake
is complete (i.e., while the client Finished message is still in flight),
when no client certificate authentication is requested. This, unlike false
start, is part of protocol design with no known security implications.
It can be enabled by setting the <abbr class="acronym">GNUTLS_ENABLE_EARLY_START</abbr> on
<a class="ref" href="#gnutls_005finit">gnutls_init</a>, and the <a class="ref" href="#gnutls_005fhandshake">gnutls_handshake</a> function will
return early, allowing the server to send data earlier.
</p>

<hr>
</div>
<div class="subsection-level-extent" id="Zero_002droundtrip-mode">
<div class="nav-panel">
<p>
Next: <a href="#Anti_002dreplay-protection" accesskey="n" rel="next">Anti-replay protection</a>, Previous: <a href="#Reducing-round_002dtrips" accesskey="p" rel="prev">Reducing round-trips</a>, Up: <a href="#Setting-up-the-transport-layer" accesskey="u" rel="up">Setting up the transport layer</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Zero_002droundtrip-mode-1"><span>6.5.3 Zero-roundtrip mode<a class="copiable-link" href="#Zero_002droundtrip-mode-1"> &para;</a></span></h4>

<p>Under TLS 1.3, when the client has already connected to the server and
is resuming a session, it can start transmitting application data during
handshake.  This is called zero round-trip time (0-RTT) mode, and the
application data sent in this mode is called early data.  The client can
send early data with <a class="ref" href="#gnutls_005frecord_005fsend_005fearly_005fdata">gnutls_record_send_early_data</a>.  The
client should call this function before calling
<a class="ref" href="#gnutls_005fhandshake">gnutls_handshake</a> and after calling
<a class="ref" href="#gnutls_005fsession_005fset_005fdata">gnutls_session_set_data</a>.
</p>
<p>Note, however, that early data has weaker security properties than
normal application data sent after handshake, such as lack of forward
secrecy, no guarantees of non-replay between connections.  Thus it is
disabled on the server side by default.  To enable it, the server
needs to:
</p><ol class="enumerate">
<li> Set <abbr class="acronym">GNUTLS_ENABLE_EARLY_DATA</abbr> on <a class="ref" href="#gnutls_005finit">gnutls_init</a>.  Note that this option only has effect on server.

</li><li> Enable anti-replay measure.  See <a class="ref" href="#Anti_002dreplay-protection">Anti-replay protection</a> for the details.
</li></ol>

<p>The server caches the received early data until it is read.  To set the
maximum amount of data to be stored in the cache, use
<a class="ref" href="#gnutls_005frecord_005fset_005fmax_005fearly_005fdata_005fsize">gnutls_record_set_max_early_data_size</a>.  After receiving the
EndOfEarlyData handshake message, the server can start retrieving the
received data with <a class="ref" href="#gnutls_005frecord_005frecv_005fearly_005fdata">gnutls_record_recv_early_data</a>.  You can
call the function either after the handshake is complete, or through a
handshake hook (<a class="ref" href="#gnutls_005fhandshake_005fset_005fhook_005ffunction">gnutls_handshake_set_hook_function</a>).
</p>
<p>When sending early data, the client should respect the maximum amount
of early data, which may have been previously advertised by the
server.  It can be checked using
<a class="ref" href="#gnutls_005frecord_005fget_005fmax_005fearly_005fdata_005fsize">gnutls_record_get_max_early_data_size</a>, right after calling
<a class="ref" href="#gnutls_005fsession_005fset_005fdata">gnutls_session_set_data</a>.
</p>
<p>After sending early data, to check whether the sent early data was
accepted by the server, use <a class="ref" href="#gnutls_005fsession_005fget_005fflags">gnutls_session_get_flags</a> and
compare the result with <abbr class="acronym">GNUTLS_SFLAGS_EARLY_DATA</abbr>.
Similarly, on the server side, the same function and flag can be used
to check whether it has actually accepted early data.
</p>

<hr>
</div>
<div class="subsection-level-extent" id="Anti_002dreplay-protection">
<div class="nav-panel">
<p>
Next: <a href="#DTLS-sessions" accesskey="n" rel="next">DTLS sessions</a>, Previous: <a href="#Zero_002droundtrip-mode" accesskey="p" rel="prev">Zero-roundtrip mode</a>, Up: <a href="#Setting-up-the-transport-layer" accesskey="u" rel="up">Setting up the transport layer</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Anti_002dreplay-protection-1"><span>6.5.4 Anti-replay protection<a class="copiable-link" href="#Anti_002dreplay-protection-1"> &para;</a></span></h4>

<p>When 0-RTT mode is used, the server must protect itself from replay
attacks, where adversary client reuses duplicate session ticket to send
early data, before the server authenticates the client.
</p>
<p>GnuTLS provides a simple mechanism against replay attacks, following the
method called ClientHello recording.  When a session ticket is accepted,
the server checks if the ClientHello message has been already seen.  If
there is a duplicate, the server rejects early data.
</p>
<p>The problem of this approach is that the number of recorded messages
grows indefinitely.  To prevent that, the server can limit the recording
to a certain time window, which can be configured with
<a class="ref" href="#gnutls_005fanti_005freplay_005fset_005fwindow">gnutls_anti_replay_set_window</a>.
</p>
<p>The anti-replay mechanism shall be globally initialized with
<a class="ref" href="#gnutls_005fanti_005freplay_005finit">gnutls_anti_replay_init</a>, and then attached to a session using
<a class="ref" href="#gnutls_005fanti_005freplay_005fenable">gnutls_anti_replay_enable</a>.  It can be deinitialized with
<a class="ref" href="#gnutls_005fanti_005freplay_005fdeinit">gnutls_anti_replay_deinit</a>.
</p>
<p>The server must also set up a database back-end to store ClientHello
messages.  That can be achieved using
<a class="ref" href="#gnutls_005fanti_005freplay_005fset_005fadd_005ffunction">gnutls_anti_replay_set_add_function</a> and
<a class="ref" href="#gnutls_005fanti_005freplay_005fset_005fptr">gnutls_anti_replay_set_ptr</a>.
</p>
<p>Note that, if the back-end stores arbitrary number of ClientHello, it
needs to periodically clean up the stored entries based on the time
window set with <a class="ref" href="#gnutls_005fanti_005freplay_005fset_005fwindow">gnutls_anti_replay_set_window</a>.  The cleanup
can be implemented by iterating through the database entries and calling
<a class="ref" href="#gnutls_005fdb_005fcheck_005fentry_005fexpire_005ftime">gnutls_db_check_entry_expire_time</a>.  This is similar to session
database cleanup used by TLS1.2 sessions.
</p>
<p>The full set up of the server using early data would be like the
following example:
</p><div class="example">
<pre class="example-preformatted">#define MAX_EARLY_DATA_SIZE 16384

static int
db_add_func(void *dbf, gnutls_datum_t key, gnutls_datum_t data)
{
    /* Return GNUTLS_E_DB_ENTRY_EXISTS, if KEY is found in the database.
     * Otherwise, store it and return 0.
     */
}

static int
handshake_hook_func(gnutls_session_t session, unsigned int htype,
                    unsigned when, unsigned int incoming, const gnutls_datum_t *msg)
{
    int ret;
    char buf[MAX_EARLY_DATA_SIZE];

    assert(htype == GNUTLS_HANDSHAKE_END_OF_EARLY_DATA);
    assert(when == GNUTLS_HOOK_POST);

    if (gnutls_session_get_flags(session) &amp; GNUTLS_SFLAGS_EARLY_DATA) {
        ret = gnutls_record_recv_early_data(session, buf, sizeof(buf));
        assert(ret &gt;= 0);
    }

    return ret;
}

int main(void)
{
  ...
  /* Initialize anti-replay measure, which can be shared
   * among multiple sessions.
   */
  gnutls_anti_replay_init(&amp;anti_replay);

  /* Set the database back-end function for the anti-replay data. */
  gnutls_anti_replay_set_add_function(anti_replay, db_add_func);
  gnutls_anti_replay_set_ptr(anti_replay, NULL);

  ...

  gnutls_init(&amp;server, GNUTLS_SERVER | GNUTLS_ENABLE_EARLY_DATA);
  gnutls_record_set_max_early_data_size(server, MAX_EARLY_DATA_SIZE);

  ...

  /* Set the anti-replay measure to the session.
   */
  gnutls_anti_replay_enable(server, anti_replay);
  ...

  /* Retrieve early data in a handshake hook;
   * you can also do that after handshake.
   */
  gnutls_handshake_set_hook_function(server, GNUTLS_HANDSHAKE_END_OF_EARLY_DATA,
                                     GNUTLS_HOOK_POST, handshake_hook_func);
  ...
}
</pre></div>


<hr>
</div>
<div class="subsection-level-extent" id="DTLS-sessions">
<div class="nav-panel">
<p>
Next: <a href="#DTLS-and-SCTP" accesskey="n" rel="next">DTLS and SCTP</a>, Previous: <a href="#Anti_002dreplay-protection" accesskey="p" rel="prev">Anti-replay protection</a>, Up: <a href="#Setting-up-the-transport-layer" accesskey="u" rel="up">Setting up the transport layer</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="DTLS-sessions-1"><span>6.5.5 DTLS sessions<a class="copiable-link" href="#DTLS-sessions-1"> &para;</a></span></h4>

<p>Because datagram TLS can operate over connections where the client
cannot be reliably verified, functionality in the form of cookies, is available to prevent
denial of service attacks to servers. <abbr class="acronym">GnuTLS</abbr> requires a server
to generate a secret key that is used to sign a cookie<a class="footnote" id="DOCF19" href="#FOOT19"><sup>19</sup></a>.
That cookie is sent to the client using <a class="ref" href="#gnutls_005fdtls_005fcookie_005fsend">gnutls_dtls_cookie_send</a>, and
the client must reply using the correct cookie. The server side
should verify the initial message sent by client using <a class="ref" href="#gnutls_005fdtls_005fcookie_005fverify">gnutls_dtls_cookie_verify</a>.
If successful the session should be initialized and associated with
the cookie using <a class="ref" href="#gnutls_005fdtls_005fprestate_005fset">gnutls_dtls_prestate_set</a>, before proceeding to
the handshake.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fkey_005fgenerate">gnutls_key_generate</a> (gnutls_datum_t * <var class="var">key</var>, unsigned int <var class="var">key_size</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fdtls_005fcookie_005fsend">gnutls_dtls_cookie_send</a> (gnutls_datum_t * <var class="var">key</var>, void * <var class="var">client_data</var>, size_t <var class="var">client_data_size</var>, gnutls_dtls_prestate_st * <var class="var">prestate</var>, gnutls_transport_ptr_t <var class="var">ptr</var>, gnutls_push_func <var class="var">push_func</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fdtls_005fcookie_005fverify">gnutls_dtls_cookie_verify</a> (gnutls_datum_t * <var class="var">key</var>, void * <var class="var">client_data</var>, size_t <var class="var">client_data_size</var>, void * <var class="var">_msg</var>, size_t <var class="var">msg_size</var>, gnutls_dtls_prestate_st * <var class="var">prestate</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fdtls_005fprestate_005fset">gnutls_dtls_prestate_set</a> (gnutls_session_t <var class="var">session</var>, gnutls_dtls_prestate_st * <var class="var">prestate</var>)</code></dt>
</dl>

<p>Note that the above apply to server side only and they are not mandatory to be
used. Not using them, however, allows denial of service attacks.
The client side cookie handling is part of <a class="ref" href="#gnutls_005fhandshake">gnutls_handshake</a>.
</p>
<p>Datagrams are typically restricted by a maximum transfer unit (MTU). For that
both client and server side should set the correct maximum transfer unit for
the layer underneath <abbr class="acronym">GnuTLS</abbr>. This will allow proper fragmentation
of DTLS messages and prevent messages from being silently discarded by the
transport layer. The &ldquo;correct&rdquo; maximum transfer unit can be obtained through
a path MTU discovery mechanism [<a class="ref" href="#RFC4821">RFC4821</a>].
</p>
<dl class="table">
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fdtls_005fset_005fmtu">gnutls_dtls_set_mtu</a> (gnutls_session_t <var class="var">session</var>, unsigned int <var class="var">mtu</var>)</code></dt>
<dt><code class="code"><var class="var">unsigned int</var> <a class="ref" href="#gnutls_005fdtls_005fget_005fmtu">gnutls_dtls_get_mtu</a> (gnutls_session_t <var class="var">session</var>)</code></dt>
<dt><code class="code"><var class="var">unsigned int</var> <a class="ref" href="#gnutls_005fdtls_005fget_005fdata_005fmtu">gnutls_dtls_get_data_mtu</a> (gnutls_session_t <var class="var">session</var>)</code></dt>
</dl>

<hr>
</div>
<div class="subsection-level-extent" id="DTLS-and-SCTP">
<div class="nav-panel">
<p>
Previous: <a href="#DTLS-sessions" accesskey="p" rel="prev">DTLS sessions</a>, Up: <a href="#Setting-up-the-transport-layer" accesskey="u" rel="up">Setting up the transport layer</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="DTLS-and-SCTP-1"><span>6.5.6 DTLS and SCTP<a class="copiable-link" href="#DTLS-and-SCTP-1"> &para;</a></span></h4>

<p>Although DTLS can run under any reliable or unreliable layer, there are
special requirements for SCTP according to [<a class="ref" href="#RFC6083">RFC6083</a>]. We summarize the
most important below, however for a full treatment we refer to [<a class="ref" href="#RFC6083">RFC6083</a>].
</p>
<ul class="itemize mark-bullet">
<li>The MTU set via <a class="ref" href="#gnutls_005fdtls_005fset_005fmtu">gnutls_dtls_set_mtu</a> must be 2^14.
</li><li>Replay detection must be disabled; use the flag <code class="code">GNUTLS_NO_REPLAY_PROTECTION</code> with <a class="ref" href="#gnutls_005finit">gnutls_init</a>.
</li><li>Retransmission of messages must be disabled; use <a class="ref" href="#gnutls_005fdtls_005fset_005ftimeouts">gnutls_dtls_set_timeouts</a>
   with a retransmission timeout larger than the total.
</li><li>Handshake, Alert and ChangeCipherSpec messages must be sent over stream 0 with unlimited reliability
   and with the ordered delivery feature.
</li><li>During a rehandshake, the caching of messages with unknown epoch is
   not handled by GnuTLS; this must be implemented in a special pull function.
</li></ul>

<hr>
</div>
</div>
<div class="section-level-extent" id="TLS-handshake">
<div class="nav-panel">
<p>
Next: <a href="#Data-transfer-and-termination" accesskey="n" rel="next">Data transfer and termination</a>, Previous: <a href="#Setting-up-the-transport-layer" accesskey="p" rel="prev">Setting up the transport layer</a>, Up: <a href="#How-to-use-GnuTLS-in-applications" accesskey="u" rel="up">How to use <abbr class="acronym">GnuTLS</abbr> in applications</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="TLS-handshake-1"><span>6.6 TLS handshake<a class="copiable-link" href="#TLS-handshake-1"> &para;</a></span></h3>
<p>Once a session has been initialized and a network
connection has been set up, TLS and DTLS protocols
perform a handshake. The handshake is the actual key
exchange.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fhandshake"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_handshake</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fhandshake"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>This function performs the handshake of the TLS/SSL protocol, and
initializes the TLS session parameters.
</p>
<p>The non-fatal errors expected by this function are:
<code class="code">GNUTLS_E_INTERRUPTED</code> , <code class="code">GNUTLS_E_AGAIN</code> ,
<code class="code">GNUTLS_E_WARNING_ALERT_RECEIVED</code> . When this function is called
for re-handshake under TLS 1.2 or earlier, the non-fatal error code
<code class="code">GNUTLS_E_GOT_APPLICATION_DATA</code>  may also be returned.
</p>
<p>The former two interrupt the handshake procedure due to the transport
layer being interrupted, and the latter because of a &quot;warning&quot; alert that
was sent by the peer (it is always a good idea to check any
received alerts). On these non-fatal errors call this function again,
until it returns 0; cf.  <code class="code">gnutls_record_get_direction()</code>  and
<code class="code">gnutls_error_is_fatal()</code> . In DTLS sessions the non-fatal error
<code class="code">GNUTLS_E_LARGE_PACKET</code>  is also possible, and indicates that
the MTU should be adjusted.
</p>
<p>When this function is called by a server after a rehandshake request
under TLS 1.2 or earlier the <code class="code">GNUTLS_E_GOT_APPLICATION_DATA</code>  error code indicates
that some data were pending prior to peer initiating the handshake.
Under TLS 1.3 this function when called after a successful handshake, is a no-op
and always succeeds in server side; in client side this function is
equivalent to <code class="code">gnutls_session_key_update()</code>  with <code class="code">GNUTLS_KU_PEER</code>  flag.
</p>
<p>This function handles both full and abbreviated TLS handshakes (resumption).
For abbreviated handshakes, in client side, the <code class="code">gnutls_session_set_data()</code> 
should be called prior to this function to set parameters from a previous session.
In server side, resumption is handled by either setting a DB back-end, or setting
up keys for session tickets.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on a successful handshake, otherwise a negative error code.
</p></dd></dl>





<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fhandshake_005fset_005ftimeout"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_handshake_set_timeout</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, unsigned int <var class="var">ms</var>)</code><a class="copiable-link" href="#index-gnutls_005fhandshake_005fset_005ftimeout"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">ms</var>: is a timeout value in milliseconds
</p>
<p>This function sets the timeout for the TLS handshake process
to the provided value. Use an  <code class="code">ms</code> value of zero to disable
timeout, or <code class="code">GNUTLS_DEFAULT_HANDSHAKE_TIMEOUT</code>  for a reasonable
default value. For the DTLS protocol, the more detailed
<code class="code">gnutls_dtls_set_timeouts()</code>  is provided.
</p>
<p>This function requires to set a pull timeout callback. See
<code class="code">gnutls_transport_set_pull_timeout_function()</code> .
</p>
<p><strong class="strong">Since:</strong> 3.1.0
</p></dd></dl>

<p>In GnuTLS 3.5.0 and later it is recommended to use <a class="ref" href="#gnutls_005fsession_005fset_005fverify_005fcert">gnutls_session_set_verify_cert</a>
for the handshake process to ensure the verification of the peer&rsquo;s identity.
That will verify the peer&rsquo;s certificate, against the trusted CA store while
accounting for stapled OCSP responses during the handshake; any error will
be returned as a handshake error.
</p>
<p>In older GnuTLS versions it is required to verify the peer&rsquo;s certificate
during the handshake by setting a callback with <a class="ref" href="#gnutls_005fcertificate_005fset_005fverify_005ffunction">gnutls_certificate_set_verify_function</a>,
and then using <a class="ref" href="#gnutls_005fcertificate_005fverify_005fpeers3">gnutls_certificate_verify_peers3</a> from it. See <a class="ref" href="#Certificate-authentication">Certificate authentication</a>
for more information.
</p>
<dl class="table">
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fsession_005fset_005fverify_005fcert">gnutls_session_set_verify_cert</a> (gnutls_session_t <var class="var">session</var>, const char * <var class="var">hostname</var>, unsigned <var class="var">flags</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fcertificate_005fverify_005fpeers3">gnutls_certificate_verify_peers3</a> (gnutls_session_t <var class="var">session</var>, const char * <var class="var">hostname</var>, unsigned int * <var class="var">status</var>)</code></dt>
</dl>

<hr>
</div>
<div class="section-level-extent" id="Data-transfer-and-termination">
<div class="nav-panel">
<p>
Next: <a href="#Buffered-data-transfer" accesskey="n" rel="next">Buffered data transfer</a>, Previous: <a href="#TLS-handshake" accesskey="p" rel="prev">TLS handshake</a>, Up: <a href="#How-to-use-GnuTLS-in-applications" accesskey="u" rel="up">How to use <abbr class="acronym">GnuTLS</abbr> in applications</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Data-transfer-and-termination-1"><span>6.7 Data transfer and termination<a class="copiable-link" href="#Data-transfer-and-termination-1"> &para;</a></span></h3>
<p>Once the handshake is complete and peer&rsquo;s identity
has been verified data can be exchanged. The available
functions resemble the POSIX <code class="code">recv</code> and <code class="code">send</code>
functions. It is suggested to use <a class="ref" href="#gnutls_005ferror_005fis_005ffatal">gnutls_error_is_fatal</a>
to check whether the error codes returned by these functions are
fatal for the protocol or can be ignored.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frecord_005fsend"><span class="category-def">Function: </span><span><code class="def-type">ssize_t</code> <strong class="def-name">gnutls_record_send</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, const void * <var class="var">data</var>, size_t <var class="var">data_size</var>)</code><a class="copiable-link" href="#index-gnutls_005frecord_005fsend"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">data</var>: contains the data to send
</p>
<p><var class="var">data_size</var>: is the length of the data
</p>
<p>This function has the similar semantics with <code class="code">send()</code> .  The only
difference is that it accepts a GnuTLS session, and uses different
error codes.
Note that if the send buffer is full, <code class="code">send()</code>  will block this
function.  See the <code class="code">send()</code>  documentation for more information.
</p>
<p>You can replace the default push function which is <code class="code">send()</code> , by using
<code class="code">gnutls_transport_set_push_function()</code> .
</p>
<p>If the EINTR is returned by the internal push function
then <code class="code">GNUTLS_E_INTERRUPTED</code>  will be returned. If
<code class="code">GNUTLS_E_INTERRUPTED</code>  or <code class="code">GNUTLS_E_AGAIN</code>  is returned, you must
call this function again with the exact same parameters, or provide a
<code class="code">NULL</code>  pointer for  <code class="code">data</code> and 0 for  <code class="code">data_size</code> , in order to write the
same data as before. If you wish to discard the previous data instead
of retrying, you must call <code class="code">gnutls_record_discard_queued()</code>  before
calling this function with different parameters. Note that the latter
works only on special transports (e.g., UDP).
cf. <code class="code">gnutls_record_get_direction()</code> .
</p>
<p>Note that in DTLS this function will return the <code class="code">GNUTLS_E_LARGE_PACKET</code> 
error code if the send data exceed the data MTU value - as returned
by <code class="code">gnutls_dtls_get_data_mtu()</code> . The errno value EMSGSIZE
also maps to <code class="code">GNUTLS_E_LARGE_PACKET</code> .
Note that since 3.2.13 this function can be called under cork in DTLS
mode, and will refuse to send data over the MTU size by returning
<code class="code">GNUTLS_E_LARGE_PACKET</code> .
</p>
<p><strong class="strong">Returns:</strong> The number of bytes sent, or a negative error code.  The
number of bytes sent might be less than  <code class="code">data_size</code> .  The maximum
number of bytes this function can send in a single call depends
on the negotiated maximum record size.
</p></dd></dl>





<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frecord_005frecv"><span class="category-def">Function: </span><span><code class="def-type">ssize_t</code> <strong class="def-name">gnutls_record_recv</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, void * <var class="var">data</var>, size_t <var class="var">data_size</var>)</code><a class="copiable-link" href="#index-gnutls_005frecord_005frecv"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">data</var>: the buffer that the data will be read into
</p>
<p><var class="var">data_size</var>: the number of requested bytes
</p>
<p>This function has the similar semantics with <code class="code">recv()</code> .  The only
difference is that it accepts a GnuTLS session, and uses different
error codes.
In the special case that the peer requests a renegotiation, the
caller will receive an error code of <code class="code">GNUTLS_E_REHANDSHAKE</code> .  In case
of a client, this message may be simply ignored, replied with an alert
<code class="code">GNUTLS_A_NO_RENEGOTIATION</code> , or replied with a new handshake,
depending on the client&rsquo;s will. A server receiving this error code
can only initiate a new handshake or terminate the session.
</p>
<p>If <code class="code">EINTR</code>  is returned by the internal pull function (the default
is <code class="code">recv()</code> ) then <code class="code">GNUTLS_E_INTERRUPTED</code>  will be returned.  If
<code class="code">GNUTLS_E_INTERRUPTED</code>  or <code class="code">GNUTLS_E_AGAIN</code>  is returned, you must
call this function again to get the data.  See also
<code class="code">gnutls_record_get_direction()</code> .
</p>
<p><strong class="strong">Returns:</strong> The number of bytes received and zero on EOF (for stream
connections).  A negative error code is returned in case of an error.
The number of bytes received might be less than the requested  <code class="code">data_size</code> .
</p></dd></dl>





<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ferror_005fis_005ffatal"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_error_is_fatal</strong> <code class="def-code-arguments">(int <var class="var">error</var>)</code><a class="copiable-link" href="#index-gnutls_005ferror_005fis_005ffatal"> &para;</a></span></dt>
<dd><p><var class="var">error</var>: is a GnuTLS error code, a negative error code
</p>
<p>If a GnuTLS function returns a negative error code you may feed that
value to this function to see if the error condition is fatal to
a TLS session (i.e., must be terminated).
</p>
<p>Note that you may also want to check the error code manually, since some
non-fatal errors to the protocol (such as a warning alert or
a rehandshake request) may be fatal for your program.
</p>
<p>This function is only useful if you are dealing with errors from
functions that relate to a TLS session (e.g., record layer or handshake
layer handling functions).
</p>
<p><strong class="strong">Returns:</strong> Non-zero value on fatal errors or zero on non-fatal.
</p></dd></dl>

<p>Although, in the TLS protocol the receive function can be called
at any time, when DTLS is used the GnuTLS receive functions must be
called once a message is available for reading, even if no data are
expected. This is because in DTLS various (internal) actions
may be required due to retransmission timers. Moreover,
an extended receive function is shown below, which allows the extraction
of the message&rsquo;s sequence number. Due to the unreliable nature of the
protocol, this field allows distinguishing out-of-order messages.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frecord_005frecv_005fseq"><span class="category-def">Function: </span><span><code class="def-type">ssize_t</code> <strong class="def-name">gnutls_record_recv_seq</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, void * <var class="var">data</var>, size_t <var class="var">data_size</var>, unsigned char * <var class="var">seq</var>)</code><a class="copiable-link" href="#index-gnutls_005frecord_005frecv_005fseq"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">data</var>: the buffer that the data will be read into
</p>
<p><var class="var">data_size</var>: the number of requested bytes
</p>
<p><var class="var">seq</var>: is the packet&rsquo;s 64-bit sequence number. Should have space for 8 bytes.
</p>
<p>This function is the same as <code class="code">gnutls_record_recv()</code> , except that
it returns in addition to data, the sequence number of the data.
This is useful in DTLS where record packets might be received
out-of-order. The returned 8-byte sequence number is an
integer in big-endian format and should be
treated as a unique message identification.
</p>
<p><strong class="strong">Returns:</strong> The number of bytes received and zero on EOF.  A negative
error code is returned in case of an error.  The number of bytes
received might be less than  <code class="code">data_size</code> .
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<p>The <a class="ref" href="#gnutls_005frecord_005fcheck_005fpending">gnutls_record_check_pending</a> helper function is available to
allow checking whether data are available to be read in a <abbr class="acronym">GnuTLS</abbr> session
buffers. Note that this function complements but does not replace <code class="code">poll</code>,
i.e., <a class="ref" href="#gnutls_005frecord_005fcheck_005fpending">gnutls_record_check_pending</a> reports no data to be read, <code class="code">poll</code>
should be called to check for data in the network buffers.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frecord_005fcheck_005fpending"><span class="category-def">Function: </span><span><code class="def-type">size_t</code> <strong class="def-name">gnutls_record_check_pending</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005frecord_005fcheck_005fpending"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>This function checks if there are unread data
in the gnutls buffers. If the return value is
non-zero the next call to <code class="code">gnutls_record_recv()</code> 
is guaranteed not to block.
</p>
<p><strong class="strong">Returns:</strong> Returns the size of the data or zero.
</p></dd></dl>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005frecord_005fget_005fdirection">gnutls_record_get_direction</a> (gnutls_session_t <var class="var">session</var>)</code></dt>
</dl>

<p>Once a TLS or DTLS session is no longer needed, it is
recommended to use <a class="ref" href="#gnutls_005fbye">gnutls_bye</a> to terminate the
session. That way the peer is notified securely about the
intention of termination, which allows distinguishing it
from a malicious connection termination.
A session can be deinitialized with the <a class="ref" href="#gnutls_005fdeinit">gnutls_deinit</a> function.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fbye"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_bye</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_close_request_t <var class="var">how</var>)</code><a class="copiable-link" href="#index-gnutls_005fbye"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">how</var>: is an integer
</p>
<p>Terminates the current TLS/SSL connection. The connection should
have been initiated using <code class="code">gnutls_handshake()</code> .   <code class="code">how</code> should be one
of <code class="code">GNUTLS_SHUT_RDWR</code> , <code class="code">GNUTLS_SHUT_WR</code> .
</p>
<p>In case of <code class="code">GNUTLS_SHUT_RDWR</code>  the TLS session gets
terminated and further receives and sends will be disallowed.  If
the return value is zero you may continue using the underlying
transport layer. <code class="code">GNUTLS_SHUT_RDWR</code>  sends an alert containing a close
request and waits for the peer to reply with the same message.
</p>
<p>In case of <code class="code">GNUTLS_SHUT_WR</code>  the TLS session gets terminated
and further sends will be disallowed. In order to reuse the
connection you should wait for an EOF from the peer.
<code class="code">GNUTLS_SHUT_WR</code>  sends an alert containing a close request.
</p>
<p>Note that not all implementations will properly terminate a TLS
connection.  Some of them, usually for performance reasons, will
terminate only the underlying transport layer, and thus not
distinguishing between a malicious party prematurely terminating
the connection and normal termination.
</p>
<p>This function may also return <code class="code">GNUTLS_E_AGAIN</code>  or
<code class="code">GNUTLS_E_INTERRUPTED</code> ; cf.  <code class="code">gnutls_record_get_direction()</code> .
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, or an error code, see
function documentation for entire semantics.
</p></dd></dl>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_deinit</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>This function clears all buffers associated with the  <code class="code">session</code> .
This function will also remove session data from the session
database if the session was terminated abnormally.
</p></dd></dl>

<hr>
</div>
<div class="section-level-extent" id="Buffered-data-transfer">
<div class="nav-panel">
<p>
Next: <a href="#Handling-alerts" accesskey="n" rel="next">Handling alerts</a>, Previous: <a href="#Data-transfer-and-termination" accesskey="p" rel="prev">Data transfer and termination</a>, Up: <a href="#How-to-use-GnuTLS-in-applications" accesskey="u" rel="up">How to use <abbr class="acronym">GnuTLS</abbr> in applications</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Buffered-data-transfer-1"><span>6.8 Buffered data transfer<a class="copiable-link" href="#Buffered-data-transfer-1"> &para;</a></span></h3>

<p>Although <a class="ref" href="#gnutls_005frecord_005fsend">gnutls_record_send</a> is sufficient to transmit data
to the peer, when many small chunks of data are to be transmitted
it is inefficient and wastes bandwidth due to the TLS record
overhead. In that case it is preferable to combine the small chunks
before transmission. The following functions provide that functionality.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frecord_005fcork"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_record_cork</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005frecord_005fcork"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>If called, <code class="code">gnutls_record_send()</code>  will no longer send any records.
Any sent records will be cached until <code class="code">gnutls_record_uncork()</code>  is called.
</p>
<p>This function is safe to use with DTLS after GnuTLS 3.3.0.
</p>
<p><strong class="strong">Since:</strong> 3.1.9
</p></dd></dl>





<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frecord_005funcork"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_record_uncork</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005frecord_005funcork"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">flags</var>: Could be zero or <code class="code">GNUTLS_RECORD_WAIT</code> 
</p>
<p>This resets the effect of <code class="code">gnutls_record_cork()</code> , and flushes any pending
data. If the <code class="code">GNUTLS_RECORD_WAIT</code>  flag is specified then this
function will block until the data is sent or a fatal error
occurs (i.e., the function will retry on <code class="code">GNUTLS_E_AGAIN</code>  and
<code class="code">GNUTLS_E_INTERRUPTED</code> ).
</p>
<p>If the flag <code class="code">GNUTLS_RECORD_WAIT</code>  is not specified and the function
is interrupted then the <code class="code">GNUTLS_E_AGAIN</code>  or <code class="code">GNUTLS_E_INTERRUPTED</code> 
errors will be returned. To obtain the data left in the corked
buffer use <code class="code">gnutls_record_check_corked()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success the number of transmitted data is returned, or
otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.1.9
</p></dd></dl>


<hr>
</div>
<div class="section-level-extent" id="Handling-alerts">
<div class="nav-panel">
<p>
Next: <a href="#Priority-Strings" accesskey="n" rel="next">Priority strings</a>, Previous: <a href="#Buffered-data-transfer" accesskey="p" rel="prev">Buffered data transfer</a>, Up: <a href="#How-to-use-GnuTLS-in-applications" accesskey="u" rel="up">How to use <abbr class="acronym">GnuTLS</abbr> in applications</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Handling-alerts-1"><span>6.9 Handling alerts<a class="copiable-link" href="#Handling-alerts-1"> &para;</a></span></h3>
<p>During a TLS connection alert messages may be exchanged by the
two peers. Those messages may be fatal, meaning the connection
must be terminated afterwards, or warning when something needs
to be reported to the peer, but without interrupting the session.
The error codes <code class="code">GNUTLS_E_WARNING_ALERT_RECEIVED</code>
or <code class="code">GNUTLS_E_FATAL_ALERT_RECEIVED</code> signal those alerts
when received, and may be returned by all GnuTLS functions that receive
data from the peer, being <a class="ref" href="#gnutls_005fhandshake">gnutls_handshake</a> and <a class="ref" href="#gnutls_005frecord_005frecv">gnutls_record_recv</a>.
</p>
<p>If those error codes are received the alert and its level should be logged
or reported to the peer using the functions below.
</p>



<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005falert_005fget"><span class="category-def">Function: </span><span><code class="def-type">gnutls_alert_description_t</code> <strong class="def-name">gnutls_alert_get</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005falert_005fget"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>This function will return the last alert number received.  This
function should be called when <code class="code">GNUTLS_E_WARNING_ALERT_RECEIVED</code>  or
<code class="code">GNUTLS_E_FATAL_ALERT_RECEIVED</code>  errors are returned by a gnutls
function.  The peer may send alerts if he encounters an error.
If no alert has been received the returned value is undefined.
</p>
<p><strong class="strong">Returns:</strong> the last alert received, a
<code class="code">gnutls_alert_description_t</code>  value.
</p></dd></dl>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005falert_005fget_005fname"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_alert_get_name</strong> <code class="def-code-arguments">(gnutls_alert_description_t <var class="var">alert</var>)</code><a class="copiable-link" href="#index-gnutls_005falert_005fget_005fname"> &para;</a></span></dt>
<dd><p><var class="var">alert</var>: is an alert number.
</p>
<p>This function will return a string that describes the given alert
number, or <code class="code">NULL</code> .  See <code class="code">gnutls_alert_get()</code> .
</p>
<p><strong class="strong">Returns:</strong> string corresponding to <code class="code">gnutls_alert_description_t</code>  value.
</p></dd></dl>

<p>The peer may also be warned or notified of a fatal issue
by using one of the functions below. All the available alerts
are listed in <a class="ref" href="#The-Alert-Protocol">The Alert Protocol</a>.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005falert_005fsend"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_alert_send</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_alert_level_t <var class="var">level</var>, gnutls_alert_description_t <var class="var">desc</var>)</code><a class="copiable-link" href="#index-gnutls_005falert_005fsend"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">level</var>: is the level of the alert
</p>
<p><var class="var">desc</var>: is the alert description
</p>
<p>This function will send an alert to the peer in order to inform
him of something important (eg. his Certificate could not be verified).
If the alert level is Fatal then the peer is expected to close the
connection, otherwise he may ignore the alert and continue.
</p>
<p>The error code of the underlying record send function will be
returned, so you may also receive <code class="code">GNUTLS_E_INTERRUPTED</code>  or
<code class="code">GNUTLS_E_AGAIN</code>  as well.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise
an error code is returned.
</p></dd></dl>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ferror_005fto_005falert"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_error_to_alert</strong> <code class="def-code-arguments">(int <var class="var">err</var>, int * <var class="var">level</var>)</code><a class="copiable-link" href="#index-gnutls_005ferror_005fto_005falert"> &para;</a></span></dt>
<dd><p><var class="var">err</var>: is a negative integer
</p>
<p><var class="var">level</var>: the alert level will be stored there
</p>
<p>Get an alert depending on the error code returned by a gnutls
function.  All alerts sent by this function should be considered
fatal.  The only exception is when  <code class="code">err</code> is <code class="code">GNUTLS_E_REHANDSHAKE</code> ,
where a warning alert should be sent to the peer indicating that no
renegotiation will be performed.
</p>
<p>If there is no mapping to a valid alert the alert to indicate
internal error (<code class="code">GNUTLS_A_INTERNAL_ERROR</code> ) is returned.
</p>
<p><strong class="strong">Returns:</strong> the alert code to use for a particular error code.
</p></dd></dl>


<hr>
</div>
<div class="section-level-extent" id="Priority-Strings">
<div class="nav-panel">
<p>
Next: <a href="#Selecting-cryptographic-key-sizes" accesskey="n" rel="next">Selecting cryptographic key sizes</a>, Previous: <a href="#Handling-alerts" accesskey="p" rel="prev">Handling alerts</a>, Up: <a href="#How-to-use-GnuTLS-in-applications" accesskey="u" rel="up">How to use <abbr class="acronym">GnuTLS</abbr> in applications</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Priority-strings"><span>6.10 Priority strings<a class="copiable-link" href="#Priority-strings"> &para;</a></span></h3>
<a class="index-entry-id" id="index-Priority-strings"></a>

<h4 class="subheading" id="How-to-use-Priority-Strings"><span>How to use Priority Strings<a class="copiable-link" href="#How-to-use-Priority-Strings"> &para;</a></span></h4>

<p>The GnuTLS priority strings specify the TLS session&rsquo;s handshake
algorithms and options in a compact, easy-to-use format. These
strings are intended as a user-specified override of the library defaults.
</p>
<p>That is, we recommend applications using the default settings
(c.f. <a class="ref" href="#gnutls_005fset_005fdefault_005fpriority">gnutls_set_default_priority</a> or
<a class="ref" href="#gnutls_005fset_005fdefault_005fpriority_005fappend">gnutls_set_default_priority_append</a>), and provide the user
with access to priority strings for overriding the default behavior,
on configuration files, or other UI. Following such a principle,
makes the GnuTLS library as the default settings provider. That is
necessary and a good practice, because TLS protocol hardening and
phasing out of legacy algorithms, is easier to coordinate when happens
in a single library.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fset_005fdefault_005fpriority">gnutls_set_default_priority</a> (gnutls_session_t <var class="var">session</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fset_005fdefault_005fpriority_005fappend">gnutls_set_default_priority_append</a> (gnutls_session_t <var class="var">session</var>, const char * <var class="var">add_prio</var>, const char ** <var class="var">err_pos</var>, unsigned <var class="var">flags</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpriority_005fset_005fdirect">gnutls_priority_set_direct</a> (gnutls_session_t <var class="var">session</var>, const char * <var class="var">priorities</var>, const char ** <var class="var">err_pos</var>)</code></dt>
</dl>

<p>The priority string translation to the internal GnuTLS form requires
processing and the generated internal form also occupies some memory.
For that, it is recommended to do that processing once in server side,
and share the generated data across sessions. The following functions
allow the generation of a &quot;priority cache&quot; and the sharing of it across
sessions.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpriority_005finit2">gnutls_priority_init2</a> (gnutls_priority_t * <var class="var">priority_cache</var>, const char * <var class="var">priorities</var>, const char ** <var class="var">err_pos</var>, unsigned <var class="var">flags</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpriority_005finit">gnutls_priority_init</a> (gnutls_priority_t * <var class="var">priority_cache</var>, const char * <var class="var">priorities</var>, const char ** <var class="var">err_pos</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpriority_005fset">gnutls_priority_set</a> (gnutls_session_t <var class="var">session</var>, gnutls_priority_t <var class="var">priority</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fpriority_005fdeinit">gnutls_priority_deinit</a> (gnutls_priority_t <var class="var">priority_cache</var>)</code></dt>
</dl>

<h4 class="subheading" id="Using-Priority-Strings"><span>Using Priority Strings<a class="copiable-link" href="#Using-Priority-Strings"> &para;</a></span></h4>

<p>A priority string string may contain a single initial keyword such as in
<a class="ref" href="#tab_003aprio_002dkeywords">Table 6.3</a> and may be followed by additional algorithm or
special keywords. Note that their description is intentionally avoiding
specific algorithm details, as the priority strings are not constant between
gnutls versions (they are periodically updated to account for cryptographic
advances while providing compatibility with old clients and servers).
</p>
<div class="float" id="tab_003aprio_002dkeywords">
<table class="multitable">
<thead><tr><th width="20%">Keyword</th><th width="70%">Description</th></tr></thead>
<tbody><tr><td width="20%">@KEYWORD</td><td width="70%">Means that a compile-time specified system configuration file (see <a class="ref" href="#System_002dwide-configuration-of-the-library">System-wide configuration of the library</a>)
will be used to expand the provided keyword. That is used to impose system-specific policies.
It may be followed by additional options that will be appended to the
system string (e.g., &quot;@SYSTEM:+SRP&quot;). The system file should have the
format &rsquo;KEYWORD=VALUE&rsquo;, e.g., &rsquo;SYSTEM=NORMAL:+ARCFOUR-128&rsquo;.

<p>Since version 3.5.1 it is allowed to specify fallback keywords by
separating them with a comma, such as @KEYWORD1,KEYWORD2, and the
first valid keyword will be used.
</p></td></tr>
<tr><td width="20%">PERFORMANCE</td><td width="70%">All the known to be secure ciphersuites are enabled,
limited to 128 bit ciphers and sorted by terms of speed
performance. The message authenticity security level is of 64 bits or more,
and the certificate verification profile is set to GNUTLS_PROFILE_LOW (80-bits).</td></tr>
<tr><td width="20%">NORMAL</td><td width="70%">Means all the known to be secure ciphersuites. The ciphers are sorted by security
margin, although the 256-bit ciphers are included as a fallback only.
The message authenticity security level is of 64 bits or more,
and the certificate verification profile is set to GNUTLS_PROFILE_LOW (80-bits).

<p>This priority string implicitly enables ECDHE and DHE. The ECDHE ciphersuites
are placed first in the priority order, but due to compatibility
issues with the DHE ciphersuites they are placed last in the priority order,
after the plain RSA ciphersuites.
</p></td></tr>
<tr><td width="20%">LEGACY</td><td width="70%">This sets the NORMAL settings that were used for GnuTLS 3.2.x or earlier. There is
no verification profile set, and the allowed DH primes are considered
weak today (but are often used by misconfigured servers).</td></tr>
<tr><td width="20%">PFS</td><td width="70%">Means all the known to be secure ciphersuites that support perfect forward
secrecy (ECDHE and DHE). The ciphers are sorted by security
margin, although the 256-bit ciphers are included as a fallback only.
The message authenticity security level is of 80 bits or more,
and the certificate verification profile is set to GNUTLS_PROFILE_LOW (80-bits).
This option is available since 3.2.4 or later.</td></tr>
<tr><td width="20%">SECURE128</td><td width="70%">Means all known to be secure ciphersuites that offer a
security level 128-bit or more.
The message authenticity security level is of 80 bits or more,
and the certificate verification profile is set to GNUTLS_PROFILE_LOW (80-bits).</td></tr>
<tr><td width="20%">SECURE192</td><td width="70%">Means all the known to be secure ciphersuites that offer a
security level 192-bit or more.
The message authenticity security level is of 128 bits or more,
and the certificate verification profile is set to GNUTLS_PROFILE_HIGH (128-bits).</td></tr>
<tr><td width="20%">SECURE256</td><td width="70%">Currently alias for SECURE192. This option, will enable ciphers which use a
256-bit key but, due to limitations of the TLS protocol, the overall security
level will be 192-bits (the security level depends on more factors than cipher key size).</td></tr>
<tr><td width="20%">SUITEB128</td><td width="70%">Means all the NSA Suite B cryptography (RFC5430) ciphersuites
with an 128 bit security level, as well as the enabling of the corresponding
verification profile.</td></tr>
<tr><td width="20%">SUITEB192</td><td width="70%">Means all the NSA Suite B cryptography (RFC5430) ciphersuites
with an 192 bit security level, as well as the enabling of the corresponding
verification profile.</td></tr>
<tr><td width="20%">NONE</td><td width="70%">Means nothing is enabled.  This disables even protocol versions.
It should be followed by the algorithms to be enabled. Note that
using this option to build a priority string gives detailed control
into the resulting settings, however with new revisions of the TLS protocol
new priority items are routinely added, and such strings are not
forward compatible with new protocols. As such, we
advice against using that option for applications targeting multiple versions
of the GnuTLS library, and recommend using the defaults (see above) or
adjusting the defaults via <a class="ref" href="#gnutls_005fset_005fdefault_005fpriority_005fappend">gnutls_set_default_priority_append</a>.</td></tr>
</tbody>
</table>
<div class="caption"><p><strong class="strong">Table 6.3: </strong>Supported initial keywords.</p></div></div>
<p>Unless the initial keyword is &quot;NONE&quot; the defaults (in preference
order) are for TLS protocols TLS 1.2, TLS1.1, TLS1.0;
for certificate types X.509.
In key exchange algorithms when in NORMAL or SECURE levels the
perfect forward secrecy algorithms take precedence of the other
protocols.  In all cases all the supported key exchange algorithms
are enabled.
</p>
<p>Note that the SECURE levels distinguish between overall security level and
message authenticity security level. That is because the message
authenticity security level requires the adversary to break
the algorithms at real-time during the protocol run, whilst
the overall security level refers to off-line adversaries
(e.g. adversaries breaking the ciphertext years after it was captured).
</p>
<p>The NONE keyword, if used, must followed by keywords specifying
the algorithms and protocols to be enabled. The other initial keywords
do not require, but may be followed by such keywords. All level keywords
can be combined, and for example a level of &quot;SECURE256:+SECURE128&quot; is
allowed.
</p>
<p>The order with which every algorithm or protocol
is specified is significant. Algorithms specified before others
will take precedence. The supported in the GnuTLS version corresponding
to this document algorithms and protocols are shown in <a class="ref" href="#tab_003aprio_002dalgorithms">Table 6.4</a>;
to list the supported algorithms in your currently using version use
<code class="code">gnutls-cli -l</code>.
</p>
<p>To avoid collisions in order to specify a protocol version
with &quot;VERS-&quot;, signature algorithms with &quot;SIGN-&quot; and certificate types with &quot;CTYPE-&quot;.
All other algorithms don&rsquo;t need a prefix. Each specified keyword (except
for <em class="emph">special keywords</em>) can be prefixed with any of the following
characters.
</p>
<dl class="table">
<dt>&rsquo;!&rsquo; or &rsquo;-&rsquo;</dt>
<dd><p>appended with an algorithm will remove this algorithm.
</p></dd>
<dt>&quot;+&quot;</dt>
<dd><p>appended with an algorithm will add this algorithm.
</p></dd>
</dl>

<div class="float" id="tab_003aprio_002dalgorithms">
<table class="multitable">
<thead><tr><th width="20%">Type</th><th width="70%">Keywords</th></tr></thead>
<tbody><tr><td width="20%">Ciphers</td><td width="70%">Examples are AES-128-GCM, AES-256-GCM, AES-256-CBC, GOST28147-TC26Z-CNT; see also
<a class="ref" href="#tab_003aciphers">Table 3.1</a> for more options. Catch all name is CIPHER-ALL which will add
all the algorithms from NORMAL priority. The shortcut for secure GOST
algorithms is CIPHER-GOST-ALL.</td></tr>
<tr><td width="20%">Key exchange</td><td width="70%">RSA, RSA-PSK, RSA-EXPORT, DHE-RSA, DHE-DSS, SRP, SRP-RSA, SRP-DSS,
PSK, DHE-PSK, ECDHE-PSK, ECDHE-RSA, ECDHE-ECDSA, VKO-GOST-12, ANON-ECDH, ANON-DH.
Catch all name is KX-ALL which will add all the algorithms from NORMAL
priority. Under TLS1.3, the DHE-PSK and ECDHE-PSK strings are equivalent
and instruct for a Diffie-Hellman key exchange using the enabled groups. The
shortcut for secure GOST algorithms is KX-GOST-ALL.</td></tr>
<tr><td width="20%">MAC</td><td width="70%">MD5, SHA1, SHA256, SHA384, GOST28147-TC26Z-IMIT, AEAD (used with
GCM ciphers only). All algorithms from NORMAL priority can be accessed with
MAC-ALL. The shortcut for secure GOST algorithms is MAC-GOST-ALL.</td></tr>
<tr><td width="20%">Compression algorithms</td><td width="70%">COMP-NULL, COMP-DEFLATE. Catch all is COMP-ALL.</td></tr>
<tr><td width="20%">TLS versions</td><td width="70%">VERS-TLS1.0, VERS-TLS1.1, VERS-TLS1.2, VERS-TLS1.3,
VERS-DTLS0.9, VERS-DTLS1.0, VERS-DTLS1.2.
Catch all are VERS-ALL, and will enable
all protocols from NORMAL priority. To distinguish between TLS and DTLS
versions you can use VERS-TLS-ALL and VERS-DTLS-ALL.</td></tr>
<tr><td width="20%">Signature algorithms</td><td width="70%">SIGN-RSA-SHA1, SIGN-RSA-SHA224,
SIGN-RSA-SHA256, SIGN-RSA-SHA384, SIGN-RSA-SHA512, SIGN-DSA-SHA1,
SIGN-DSA-SHA224, SIGN-DSA-SHA256, SIGN-RSA-MD5, SIGN-ECDSA-SHA1,
SIGN-ECDSA-SHA224, SIGN-ECDSA-SHA256, SIGN-ECDSA-SHA384, SIGN-ECDSA-SHA512,
SIGN-EdDSA-Ed25519, SIGN-EdDSA-Ed448,
SIGN-RSA-PSS-SHA256, SIGN-RSA-PSS-SHA384, SIGN-RSA-PSS-SHA512,
SIGN-GOSTR341001, SIGN-GOSTR341012-256, SIGN-GOSTR341012-512.
Catch all which enables all algorithms from NORMAL priority is SIGN-ALL.
Shortcut which enables secure GOST algorithms is SIGN-GOST-ALL.
This option is only considered for TLS 1.2 and later.</td></tr>
<tr><td width="20%">Groups</td><td width="70%">GROUP-SECP192R1, GROUP-SECP224R1, GROUP-SECP256R1, GROUP-SECP384R1,
GROUP-SECP521R1, GROUP-X25519, GROUP-X448, GROUP-GC256B, GROUP-GC512A,
GROUP-FFDHE2048, GROUP-FFDHE3072, GROUP-FFDHE4096, GROUP-FFDHE6144, and
GROUP-FFDHE8192.
Groups include both elliptic curve groups, e.g., SECP256R1, as well as
finite field groups such as FFDHE2048. Catch all which enables all groups
from NORMAL priority is GROUP-ALL. The helper keywords GROUP-DH-ALL,
GROUP-GOST-ALL and GROUP-EC-ALL are also available, restricting the groups
to finite fields (DH), GOST curves and generic elliptic curves.</td></tr>
<tr><td width="20%">Elliptic curves (legacy)</td><td width="70%">CURVE-SECP192R1, CURVE-SECP224R1, CURVE-SECP256R1, CURVE-SECP384R1,
CURVE-SECP521R1, CURVE-X25519, and CURVE-X448.
Catch all which enables all curves from NORMAL priority is CURVE-ALL. Note
that the CURVE keyword is kept for backwards compatibility only, for new
applications see the GROUP keyword above.</td></tr>
<tr><td width="20%">Certificate types</td><td width="70%">Certificate types can be given in a symmetric fashion (i.e. the same for
both client and server) or, as of GnuTLS 3.6.4, in an asymmetric fashion
(i.e. different for the client than for the server). Alternative certificate
types must be explicitly enabled via flags in <a class="ref" href="#gnutls_005finit">gnutls_init</a>.

<p>The currently supported types are CTYPE-X509, CTYPE-RAWPK which apply both to
client and server; catch all is CTYPE-ALL. The types CTYPE-CLI-X509, CTYPE-SRV-X509,
CTYPE-CLI-RAWPK, CTYPE-SRV-RAWPK can be used to specialize on client or server;
catch all is CTYPE-CLI-ALL and CTYPE-SRV-ALL. The type &rsquo;X509&rsquo; is aliased to &rsquo;X.509&rsquo;
for legacy reasons.
</p></td></tr>
<tr><td width="20%">Generic</td><td width="70%">The keyword GOST is a shortcut for secure GOST algorithms (MACs, ciphers,
KXes, groups and signatures). For example the following string will enable all
TLS 1.2 GOST ciphersuites: &rsquo;NONE:+VERS-TLS1.2:+GOST&rsquo;.</td></tr>
</tbody>
</table>
<div class="caption"><p><strong class="strong">Table 6.4: </strong>The supported algorithm keywords in priority strings.</p></div></div>
<p>Note that the finite field groups (indicated by the FFDHE prefix) and DHE key
exchange methods are generally slower<a class="footnote" id="DOCF20" href="#FOOT20"><sup>20</sup></a> than their elliptic curves counterpart
(ECDHE).
</p>
<p>The available special keywords are shown in <a class="ref" href="#tab_003aprio_002dspecial1">Table 6.5</a>
and <a class="ref" href="#tab_003aprio_002dspecial2">Table 6.6</a>.
</p>
<div class="float" id="tab_003aprio_002dspecial1">
<table class="multitable">
<thead><tr><th width="45%">Keyword</th><th width="45%">Description</th></tr></thead>
<tbody><tr><td width="45%">%COMPAT</td><td width="45%">will enable compatibility mode. It might mean that violations
of the protocols are allowed as long as maximum compatibility with
problematic clients and servers is achieved. More specifically this
string will tolerate packets over the maximum allowed TLS record,
and add a padding to TLS Client Hello packet to prevent it being in the
256-512 range which is known to be causing issues with a commonly used
firewall (see the %DUMBFW option).</td></tr>
<tr><td width="45%">%DUMBFW</td><td width="45%">will add a private extension with bogus data that make the client
hello exceed 512 bytes. This avoids a black hole behavior in some
firewalls. This is the [<a class="ref" href="#RFC7685">RFC7685</a>] client hello padding extension, also enabled
with %COMPAT.</td></tr>
<tr><td width="45%">%NO_EXTENSIONS</td><td width="45%">will prevent the sending of any TLS extensions in client side. Note
that TLS 1.2 requires extensions to be used, as well as safe
renegotiation thus this option must be used with care. When this option
is set no versions later than TLS1.2 can be negotiated.</td></tr>
<tr><td width="45%">%NO_SHUFFLE_EXTENSIONS</td><td width="45%">will prevent randomizing the order of ClientHello extensions. By
default, those extensions are randomized to make fingerprinting harder.</td></tr>
<tr><td width="45%">%NO_STATUS_REQUEST</td><td width="45%">will prevent sending of the TLS status_request extension in client side.</td></tr>
<tr><td width="45%">%NO_TICKETS</td><td width="45%">will prevent the advertizing of the TLS session ticket extension.</td></tr>
<tr><td width="45%">%NO_TICKETS_TLS12</td><td width="45%">will prevent the advertizing of the TLS session ticket extension in TLS 1.2.
This is implied by the PFS keyword.</td></tr>
<tr><td width="45%">%NO_SESSION_HASH</td><td width="45%">will prevent the advertizing the TLS extended master secret (session hash)
extension.</td></tr>
<tr><td width="45%">%FORCE_SESSION_HASH</td><td width="45%">negotiate the TLS extended master secret (session hash) extension.
Specifying both %NO_SESSION_HASH and %FORCE_SESSION_HASH is not
supported, and the behavior is undefined.</td></tr>
<tr><td width="45%">%SERVER_PRECEDENCE</td><td width="45%">The ciphersuite will be selected according to server priorities
and not the client&rsquo;s.</td></tr>
<tr><td width="45%">%SSL3_RECORD_VERSION</td><td width="45%">will use SSL3.0 record version in client hello.
By default GnuTLS will set the minimum supported version as the
client hello record version (do not confuse that version with the
proposed handshake version at the client hello).</td></tr>
<tr><td width="45%">%LATEST_RECORD_VERSION</td><td width="45%">will use the latest TLS version record version in client hello.</td></tr>
</tbody>
</table>
<div class="caption"><p><strong class="strong">Table 6.5: </strong>Special priority string keywords.</p></div></div>
<div class="float" id="tab_003aprio_002dspecial2">
<table class="multitable">
<thead><tr><th width="45%">Keyword</th><th width="45%">Description</th></tr></thead>
<tbody><tr><td width="45%">%STATELESS_COMPRESSION</td><td width="45%">ignored; no longer used.</td></tr>
<tr><td width="45%">%DISABLE_WILDCARDS</td><td width="45%">will disable matching wildcards when comparing hostnames
in certificates.</td></tr>
<tr><td width="45%">%NO_ETM</td><td width="45%">will disable the encrypt-then-mac TLS extension (RFC7366). This is
implied by the %COMPAT keyword.</td></tr>
<tr><td width="45%">%FORCE_ETM</td><td width="45%">negotiate CBC ciphersuites only when both sides of the connection support
encrypt-then-mac TLS extension (RFC7366).</td></tr>
<tr><td width="45%">%DISABLE_SAFE_RENEGOTIATION</td><td width="45%">will completely disable safe renegotiation.  Do not use unless you
know what you are doing.</td></tr>
<tr><td width="45%">%UNSAFE_RENEGOTIATION</td><td width="45%">will allow handshakes and re-handshakes
without the safe renegotiation extension.  Note that for clients
this mode is insecure (you may be under attack), and for servers it
will allow insecure clients to connect (which could be fooled by an
attacker).  Do not use unless you know what you are doing and want
maximum compatibility.</td></tr>
<tr><td width="45%">%PARTIAL_RENEGOTIATION</td><td width="45%">will allow initial handshakes to proceed,
but not re-handshakes.  This leaves the client vulnerable to attack,
and servers will be compatible with non-upgraded clients for
initial handshakes.  This is currently the default for clients and
servers, for compatibility reasons.</td></tr>
<tr><td width="45%">%SAFE_RENEGOTIATION</td><td width="45%">will enforce safe renegotiation.  Clients and
servers will refuse to talk to an insecure peer.  Currently this
causes interoperability problems, but is required for full protection.</td></tr>
<tr><td width="45%">%FALLBACK_SCSV</td><td width="45%">will enable the use of the fallback signaling cipher suite value in the
client hello.  Note that this should be set only by applications that
try to reconnect with a downgraded protocol version. See RFC7507 for
details.</td></tr>
<tr><td width="45%">%DISABLE_TLS13_COMPAT_MODE</td><td width="45%">will disable TLS 1.3 middlebox compatibility mode (RFC8446, Appendix
D.4) for non-compliant middleboxes.</td></tr>
<tr><td width="45%">%VERIFY_ALLOW_BROKEN</td><td width="45%">will allow signatures with known to be broken algorithms (such as MD5 or
SHA1) in certificate chains.</td></tr>
<tr><td width="45%">%VERIFY_ALLOW_SIGN_RSA_MD5</td><td width="45%">will allow RSA-MD5 signatures in certificate chains.</td></tr>
<tr><td width="45%">%VERIFY_ALLOW_SIGN_WITH_SHA1</td><td width="45%">will allow signatures with SHA1 hash algorithm in certificate chains.</td></tr>
<tr><td width="45%">%VERIFY_DISABLE_CRL_CHECKS</td><td width="45%">will disable CRL or OCSP checks in the verification of the certificate chain.</td></tr>
<tr><td width="45%">%VERIFY_ALLOW_X509_V1_CA_CRT</td><td width="45%">will allow V1 CAs in chains.</td></tr>
<tr><td width="45%">%PROFILE_(LOW|LEGACY|MEDIUM|HIGH|ULTRA|FUTURE)</td><td width="45%">require a certificate verification profile the corresponds to the specified
security level, see <a class="ref" href="#tab_003akey_002dsizes">Table 6.7</a> for the mappings to values.</td></tr>
<tr><td width="45%">%PROFILE_(SUITEB128|SUITEB192)</td><td width="45%">require a certificate verification profile the corresponds to SUITEB. Note
that an initial keyword that enables SUITEB automatically sets the profile.</td></tr>
</tbody>
</table>
<div class="caption"><p><strong class="strong">Table 6.6: </strong>More priority string keywords.</p></div></div>
<p>Finally the ciphersuites enabled by any priority string can be
listed using the <code class="code">gnutls-cli</code> application (see <a class="ref" href="#gnutls_002dcli-Invocation">gnutls-cli Invocation</a>),
or by using the priority functions as in <a class="ref" href="#Listing-the-ciphersuites-in-a-priority-string">Listing the ciphersuites in a priority string</a>.
</p>
<p>Example priority strings are:
</p><div class="example">
<pre class="example-preformatted">The system imposed security level:
    &quot;SYSTEM&quot;

The default priority without the HMAC-MD5:
    &quot;NORMAL:-MD5&quot;

Specifying RSA with AES-128-CBC:
    &quot;NONE:+VERS-TLS-ALL:+MAC-ALL:+RSA:+AES-128-CBC:+SIGN-ALL:+COMP-NULL&quot;

Specifying the defaults plus ARCFOUR-128:
    &quot;NORMAL:+ARCFOUR-128&quot;

Enabling the 128-bit secure ciphers, while disabling TLS 1.0:
    &quot;SECURE128:-VERS-TLS1.0&quot;

Enabling the 128-bit and 192-bit secure ciphers, while disabling all TLS versions
except TLS 1.2:
    &quot;SECURE128:+SECURE192:-VERS-ALL:+VERS-TLS1.2&quot;
</pre></div>

<hr>
</div>
<div class="section-level-extent" id="Selecting-cryptographic-key-sizes">
<div class="nav-panel">
<p>
Next: <a href="#Advanced-topics" accesskey="n" rel="next">Advanced topics</a>, Previous: <a href="#Priority-Strings" accesskey="p" rel="prev">Priority strings</a>, Up: <a href="#How-to-use-GnuTLS-in-applications" accesskey="u" rel="up">How to use <abbr class="acronym">GnuTLS</abbr> in applications</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Selecting-cryptographic-key-sizes-1"><span>6.11 Selecting cryptographic key sizes<a class="copiable-link" href="#Selecting-cryptographic-key-sizes-1"> &para;</a></span></h3>
<a class="index-entry-id" id="index-key-sizes"></a>

<p>Because many algorithms are involved in TLS, it is not easy to set
a consistent security level.  For this reason in <a class="ref" href="#tab_003akey_002dsizes">Table 6.7</a> we
present some correspondence between key sizes of symmetric algorithms
and public key algorithms based on [<a class="ref" href="#ECRYPT">ECRYPT</a>].
Those can be used to generate certificates with
appropriate key sizes as well as select parameters for Diffie-Hellman and SRP
authentication.
</p>
<div class="float" id="tab_003akey_002dsizes">
<table class="multitable">
<thead><tr><th width="10%">Security bits</th><th width="12%">RSA, DH and SRP parameter size</th><th width="10%">ECC key size</th><th width="20%">Security parameter (profile)</th><th width="32%">Description</th></tr></thead>
<tbody><tr><td width="10%">&lt;64</td><td width="12%">&lt;768</td><td width="10%">&lt;128</td><td width="20%"><code class="code">INSECURE</code></td><td width="32%">Considered to be insecure</td></tr>
<tr><td width="10%">64</td><td width="12%">768</td><td width="10%">128</td><td width="20%"><code class="code">VERY WEAK</code></td><td width="32%">Short term protection against individuals</td></tr>
<tr><td width="10%">72</td><td width="12%">1008</td><td width="10%">160</td><td width="20%"><code class="code">WEAK</code></td><td width="32%">Short term protection against small organizations</td></tr>
<tr><td width="10%">80</td><td width="12%">1024</td><td width="10%">160</td><td width="20%"><code class="code">LOW</code></td><td width="32%">Very short term protection against agencies (corresponds to ENISA legacy level)</td></tr>
<tr><td width="10%">96</td><td width="12%">1776</td><td width="10%">192</td><td width="20%"><code class="code">LEGACY</code></td><td width="32%">Legacy standard level</td></tr>
<tr><td width="10%">112</td><td width="12%">2048</td><td width="10%">224</td><td width="20%"><code class="code">MEDIUM</code></td><td width="32%">Medium-term protection</td></tr>
<tr><td width="10%">128</td><td width="12%">3072</td><td width="10%">256</td><td width="20%"><code class="code">HIGH</code></td><td width="32%">Long term protection (corresponds to ENISA future level)</td></tr>
<tr><td width="10%">192</td><td width="12%">8192</td><td width="10%">384</td><td width="20%"><code class="code">ULTRA</code></td><td width="32%">Even longer term protection</td></tr>
<tr><td width="10%">256</td><td width="12%">15424</td><td width="10%">512</td><td width="20%"><code class="code">FUTURE</code></td><td width="32%">Foreseeable future</td></tr>
</tbody>
</table>
<div class="caption"><p><strong class="strong">Table 6.7: </strong>Key sizes and security parameters.</p></div></div>
<p>The first column  provides a security parameter in a number of bits. This
gives an indication of the number of combinations to be tried by an adversary
to brute force a key. For example to test all possible keys in a 112 bit security parameter
<em class="math">2^{112}</em> combinations have to be tried. For today&rsquo;s technology this is infeasible.
The next two columns correlate the security
parameter with actual bit sizes of parameters for DH, RSA, SRP and ECC algorithms.
A mapping to <code class="code">gnutls_sec_param_t</code> value is given for each security parameter, on
the next column, and finally a brief description of the level.
</p>

<p>Note, however, that the values suggested here are nothing more than an
educated guess that is valid today. There are no guarantees that an
algorithm will remain unbreakable or that these values will remain
constant in time. There could be scientific breakthroughs that cannot
be predicted or total failure of the current public key systems by
quantum computers. On the other hand though the cryptosystems used in
TLS are selected in a conservative way and such catastrophic
breakthroughs or failures are believed to be unlikely.
The NIST publication SP 800-57 [<a class="ref" href="#NISTSP80057">NISTSP80057</a>] contains a similar
table.
</p>
<p>When using <abbr class="acronym">GnuTLS</abbr> and a decision on bit sizes for a public
key algorithm is required, use of the following functions is
recommended:
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsec_005fparam_005fto_005fpk_005fbits"><span class="category-def">Function: </span><span><code class="def-type">unsigned int</code> <strong class="def-name">gnutls_sec_param_to_pk_bits</strong> <code class="def-code-arguments">(gnutls_pk_algorithm_t <var class="var">algo</var>, gnutls_sec_param_t <var class="var">param</var>)</code><a class="copiable-link" href="#index-gnutls_005fsec_005fparam_005fto_005fpk_005fbits"> &para;</a></span></dt>
<dd><p><var class="var">algo</var>: is a public key algorithm
</p>
<p><var class="var">param</var>: is a security parameter
</p>
<p>When generating private and public key pairs a difficult question
is which size of &quot;bits&quot; the modulus will be in RSA and the group size
in DSA. The easy answer is 1024, which is also wrong. This function
will convert a human understandable security parameter to an
appropriate size for the specific algorithm.
</p>
<p><strong class="strong">Returns:</strong> The number of bits, or (0).
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>





<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpk_005fbits_005fto_005fsec_005fparam"><span class="category-def">Function: </span><span><code class="def-type">gnutls_sec_param_t</code> <strong class="def-name">gnutls_pk_bits_to_sec_param</strong> <code class="def-code-arguments">(gnutls_pk_algorithm_t <var class="var">algo</var>, unsigned int <var class="var">bits</var>)</code><a class="copiable-link" href="#index-gnutls_005fpk_005fbits_005fto_005fsec_005fparam"> &para;</a></span></dt>
<dd><p><var class="var">algo</var>: is a public key algorithm
</p>
<p><var class="var">bits</var>: is the number of bits
</p>
<p>This is the inverse of <code class="code">gnutls_sec_param_to_pk_bits()</code> . Given an algorithm
and the number of bits, it will return the security parameter. This is
a rough indication.
</p>
<p><strong class="strong">Returns:</strong> The security parameter.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<p>Those functions will convert a human understandable security parameter
of <code class="code">gnutls_sec_param_t</code> type, to a number of bits suitable for a public
key algorithm.
</p>
<dl class="table">
<dt><code class="code"><var class="var">const char *</var> <a class="ref" href="#gnutls_005fsec_005fparam_005fget_005fname">gnutls_sec_param_get_name</a> (gnutls_sec_param_t <var class="var">param</var>)</code></dt>
</dl>

<p>The following functions will set the minimum acceptable group size for Diffie-Hellman
and SRP authentication.
</p><dl class="table">
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fdh_005fset_005fprime_005fbits">gnutls_dh_set_prime_bits</a> (gnutls_session_t <var class="var">session</var>, unsigned int <var class="var">bits</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fsrp_005fset_005fprime_005fbits">gnutls_srp_set_prime_bits</a> (gnutls_session_t <var class="var">session</var>, unsigned int <var class="var">bits</var>)</code></dt>
</dl>


<hr>
</div>
<div class="section-level-extent" id="Advanced-topics">
<div class="nav-panel">
<p>
Previous: <a href="#Selecting-cryptographic-key-sizes" accesskey="p" rel="prev">Selecting cryptographic key sizes</a>, Up: <a href="#How-to-use-GnuTLS-in-applications" accesskey="u" rel="up">How to use <abbr class="acronym">GnuTLS</abbr> in applications</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Advanced-topics-1"><span>6.12 Advanced topics<a class="copiable-link" href="#Advanced-topics-1"> &para;</a></span></h3>


<ul class="mini-toc">
<li><a href="#Virtual-hosts-and-credentials" accesskey="1">Virtual hosts and credentials</a></li>
<li><a href="#Session-resumption" accesskey="2">Session resumption</a></li>
<li><a href="#Certificate-verification" accesskey="3">Certificate verification</a></li>
<li><a href="#TLS-1_002e2-re_002dauthentication" accesskey="4">TLS 1.2 re-authentication</a></li>
<li><a href="#TLS-1_002e3-re_002dauthentication-and-re_002dkey" accesskey="5">TLS 1.3 re-authentication and re-key</a></li>
<li><a href="#Parameter-generation" accesskey="6">Parameter generation</a></li>
<li><a href="#Deriving-keys-for-other-applications_002fprotocols" accesskey="7">Deriving keys for other applications/protocols</a></li>
<li><a href="#Channel-Bindings" accesskey="8">Channel bindings</a></li>
<li><a href="#Interoperability" accesskey="9">Interoperability</a></li>
<li><a href="#Compatibility-with-the-OpenSSL-library">Compatibility with the OpenSSL library</a></li>
</ul>
<hr>
<div class="subsection-level-extent" id="Virtual-hosts-and-credentials">
<div class="nav-panel">
<p>
Next: <a href="#Session-resumption" accesskey="n" rel="next">Session resumption</a>, Up: <a href="#Advanced-topics" accesskey="u" rel="up">Advanced topics</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Virtual-hosts-and-credentials-1"><span>6.12.1 Virtual hosts and credentials<a class="copiable-link" href="#Virtual-hosts-and-credentials-1"> &para;</a></span></h4>
<a class="index-entry-id" id="index-virtual-hosts"></a>
<a class="index-entry-id" id="index-credentials"></a>

<p>Often when operating with virtual hosts, one may not want to associate
a particular certificate set to the credentials function early, before
the virtual host is known. That can be achieved by calling
<a class="ref" href="#gnutls_005fcredentials_005fset">gnutls_credentials_set</a> within a handshake pre-hook for client
hello. That message contains the peer&rsquo;s intended hostname, and if read,
and the appropriate credentials are set, gnutls will be able to
continue in the handshake process. A brief usage example is shown
below.
</p>
<div class="example">
<pre class="example-preformatted">static int ext_hook_func(void *ctx, unsigned tls_id,
                         const unsigned char *data, unsigned size)
{
	if (tls_id == 0) { /* server name */
		/* figure the advertised name - the following hack
                 * relies on the fact that this extension only supports
                 * DNS names, and due to a protocol bug cannot be extended
                 * to support anything else. */
		if (name &lt; 5) return 0;
		name = data+5;
		name_size = size-5;
	}
	return 0;
}

static int
handshake_hook_func(gnutls_session_t session, unsigned int htype,
                    unsigned when, unsigned int incoming, const gnutls_datum_t *msg)
{
    int ret;

    assert(htype == GNUTLS_HANDSHAKE_CLIENT_HELLO);
    assert(when == GNUTLS_HOOK_PRE);

    ret = gnutls_ext_raw_parse(NULL, ext_hook_func, msg,
                               GNUTLS_EXT_RAW_FLAG_TLS_CLIENT_HELLO);
    assert(ret &gt;= 0);

    gnutls_credentials_set(session, GNUTLS_CRD_CERTIFICATE, cred);

    return ret;
}

int main(void)
{
  ...

  gnutls_handshake_set_hook_function(server, GNUTLS_HANDSHAKE_CLIENT_HELLO,
                                     GNUTLS_HOOK_PRE, handshake_hook_func);
  ...
}
</pre></div>





<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fhandshake_005fset_005fhook_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_handshake_set_hook_function</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, unsigned int <var class="var">htype</var>, int <var class="var">when</var>, gnutls_handshake_hook_func <var class="var">func</var>)</code><a class="copiable-link" href="#index-gnutls_005fhandshake_005fset_005fhook_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type
</p>
<p><var class="var">htype</var>: the <code class="code">gnutls_handshake_description_t</code>  of the message to hook at
</p>
<p><var class="var">when</var>: <code class="code">GNUTLS_HOOK_</code> * depending on when the hook function should be called
</p>
<p><var class="var">func</var>: is the function to be called
</p>
<p>This function will set a callback to be called after or before the specified
handshake message has been received or generated. This is a
generalization of <code class="code">gnutls_handshake_set_post_client_hello_function()</code> .
</p>
<p>To call the hook function prior to the message being generated or processed
use <code class="code">GNUTLS_HOOK_PRE</code>  as  <code class="code">when</code> parameter, <code class="code">GNUTLS_HOOK_POST</code>  to call
after, and <code class="code">GNUTLS_HOOK_BOTH</code>  for both cases.
</p>
<p>This callback must return 0 on success or a gnutls error code to
terminate the handshake.
</p>
<p>To hook at all handshake messages use an  <code class="code">htype</code> of <code class="code">GNUTLS_HANDSHAKE_ANY</code> .
</p>
<p><strong class="strong">Warning:</strong> You should not use this function to terminate the
handshake based on client input unless you know what you are
doing. Before the handshake is finished there is no way to know if
there is a man-in-the-middle attack being performed.
</p></dd></dl>

<hr>
</div>
<div class="subsection-level-extent" id="Session-resumption">
<div class="nav-panel">
<p>
Next: <a href="#Certificate-verification" accesskey="n" rel="next">Certificate verification</a>, Previous: <a href="#Virtual-hosts-and-credentials" accesskey="p" rel="prev">Virtual hosts and credentials</a>, Up: <a href="#Advanced-topics" accesskey="u" rel="up">Advanced topics</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Session-resumption-1"><span>6.12.2 Session resumption<a class="copiable-link" href="#Session-resumption-1"> &para;</a></span></h4>
<a class="index-entry-id" id="index-resuming-sessions-1"></a>
<a class="index-entry-id" id="index-session-resumption-1"></a>

<p>To reduce time and network traffic spent in a handshake the client can
request session resumption from a server that previously shared a
session with the client.
</p>
<p>Under TLS 1.2, in order to support resumption a server can either store
the session security parameters in a local database or use session
tickets (see <a class="ref" href="#Session-tickets">Session tickets</a>) to delegate storage to the client.
</p>
<p>Under TLS 1.3, session resumption is only available through session
tickets, and multiple tickets could be sent from server to client. That
provides the following advantages:
</p><ul class="itemize mark-bullet">
<li>When tickets are not re-used the subsequent client sessions cannot be associated with each other by an eavesdropper
</li><li>On post-handshake authentication the server may send different tickets asynchronously for each identity used by client.
</li></ul>

<h4 class="subsubheading" id="Client-side-1"><span>Client side<a class="copiable-link" href="#Client-side-1"> &para;</a></span></h4>

<p>The client has to retrieve and store the session parameters. Before
establishing a new session to the same server the parameters must be
re-associated with the GnuTLS session using
<a class="ref" href="#gnutls_005fsession_005fset_005fdata">gnutls_session_set_data</a>.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fsession_005fget_005fdata2">gnutls_session_get_data2</a> (gnutls_session_t <var class="var">session</var>, gnutls_datum_t * <var class="var">data</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fsession_005fset_005fdata">gnutls_session_set_data</a> (gnutls_session_t <var class="var">session</var>, const void * <var class="var">session_data</var>, size_t <var class="var">session_data_size</var>)</code></dt>
</dl>

<p>Keep in mind that sessions will be expired after some time, depending
on the server, and a server may choose not to resume a session
even when requested to.  The expiration is to prevent temporal session keys
from becoming long-term keys. Also note that as a client you must enable,
using the priority functions, at least the algorithms used in the last session.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsession_005fis_005fresumed"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_session_is_resumed</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fsession_005fis_005fresumed"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>Checks whether session is resumed or not. This is functional
for both server and client side.
</p>
<p><strong class="strong">Returns:</strong> non zero if this session is resumed, or a zero if this is
a new session.
</p></dd></dl>





<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsession_005fget_005fid2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_session_get_id2</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_datum_t * <var class="var">session_id</var>)</code><a class="copiable-link" href="#index-gnutls_005fsession_005fget_005fid2"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">session_id</var>: will point to the session ID.
</p>
<p>Returns the TLS session identifier. The session ID is selected by the
server, and in older versions of TLS was a unique identifier shared
between client and server which was persistent across resumption.
In the latest version of TLS (1.3) or TLS 1.2 with session tickets, the
notion of session identifiers is undefined and cannot be relied for uniquely
identifying sessions across client and server.
</p>
<p>In client side this function returns the identifier returned by the
server, and cannot be assumed to have any relation to session resumption.
In server side this function is guaranteed to return a persistent
identifier of the session since GnuTLS 3.6.4, which may not necessarily
map into the TLS session ID value. Prior to that version the value
could only be considered a persistent identifier, under TLS1.2 or earlier
and when no session tickets were in use.
</p>
<p>The session identifier value returned is always less than
<code class="code">GNUTLS_MAX_SESSION_ID_SIZE</code>  and should be treated as constant.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise
an error code is returned.
</p>
<p><strong class="strong">Since:</strong> 3.1.4
</p></dd></dl>

<h4 class="subsubheading" id="Server-side-1"><span>Server side<a class="copiable-link" href="#Server-side-1"> &para;</a></span></h4>

<p>A server enabling both session tickets and a storage for session data
would use session tickets when clients support it and the storage otherwise.
</p>
<p>A storing server needs to specify callback functions to store, retrieve and delete session data. These can be
registered with the functions below. The stored sessions in the database can be checked using <a class="ref" href="#gnutls_005fdb_005fcheck_005fentry">gnutls_db_check_entry</a>
for expiration.
</p>
<dl class="table">
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fdb_005fset_005fretrieve_005ffunction">gnutls_db_set_retrieve_function</a> (gnutls_session_t <var class="var">session</var>, gnutls_db_retr_func <var class="var">retr_func</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fdb_005fset_005fstore_005ffunction">gnutls_db_set_store_function</a> (gnutls_session_t <var class="var">session</var>, gnutls_db_store_func <var class="var">store_func</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fdb_005fset_005fptr">gnutls_db_set_ptr</a> (gnutls_session_t <var class="var">session</var>, void * <var class="var">ptr</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fdb_005fset_005fremove_005ffunction">gnutls_db_set_remove_function</a> (gnutls_session_t <var class="var">session</var>, gnutls_db_remove_func <var class="var">rem_func</var>)</code></dt>
</dl>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fdb_005fcheck_005fentry">gnutls_db_check_entry</a> (gnutls_session_t <var class="var">session</var>, gnutls_datum_t <var class="var">session_entry</var>)</code></dt>
</dl>

<p>A server supporting session tickets must generate ticket encryption
and authentication keys using <a class="ref" href="#gnutls_005fsession_005fticket_005fkey_005fgenerate">gnutls_session_ticket_key_generate</a>.
Those keys should be associated with the GnuTLS session using
<a class="ref" href="#gnutls_005fsession_005fticket_005fenable_005fserver">gnutls_session_ticket_enable_server</a>.
</p>
<p>Those will be the initial keys, but GnuTLS will rotate them regularly. The key rotation interval
can be changed with <a class="ref" href="#gnutls_005fdb_005fset_005fcache_005fexpiration">gnutls_db_set_cache_expiration</a> and will be set to
three times the ticket expiration time (ie. three times the value given in that function).
Every such interval, new keys will be generated from those initial keys. This is a necessary mechanism
to prevent the keys from becoming long-term keys
and as such preserve forward-secrecy in the issued session tickets. If no explicit key rotation interval
is provided, GnuTLS will rotate them every 18 hours by default.
</p>
<p>The master key can be shared between processes or between systems. Processes which share the same master key
will generate the same rotated subkeys, assuming they share the same time (irrespective of timezone differences).
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsession_005fticket_005fenable_005fserver"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_session_ticket_enable_server</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, const gnutls_datum_t * <var class="var">key</var>)</code><a class="copiable-link" href="#index-gnutls_005fsession_005fticket_005fenable_005fserver"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">key</var>: key to encrypt session parameters.
</p>
<p>Request that the server should attempt session resumption using
session tickets, i.e., by delegating storage to the client.
 <code class="code">key</code> must be initialized using <code class="code">gnutls_session_ticket_key_generate()</code> .
To avoid leaking that key, use <code class="code">gnutls_memset()</code>  prior to
releasing it.
</p>
<p>The default ticket expiration time can be overridden using
<code class="code">gnutls_db_set_cache_expiration()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, or an
error code.
</p>
<p><strong class="strong">Since:</strong> 2.10.0
</p></dd></dl>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsession_005fticket_005fkey_005fgenerate"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_session_ticket_key_generate</strong> <code class="def-code-arguments">(gnutls_datum_t * <var class="var">key</var>)</code><a class="copiable-link" href="#index-gnutls_005fsession_005fticket_005fkey_005fgenerate"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: is a pointer to a <code class="code">gnutls_datum_t</code>  which will contain a newly
created key.
</p>
<p>Generate a random key to encrypt security parameters within
SessionTicket.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, or an
error code.
</p>
<p><strong class="strong">Since:</strong> 2.10.0
</p></dd></dl>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsession_005fresumption_005frequested"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_session_resumption_requested</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fsession_005fresumption_005frequested"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>Check whether the client has asked for session resumption.
This function is valid only on server side.
</p>
<p><strong class="strong">Returns:</strong> non zero if session resumption was asked, or a zero if not.
</p></dd></dl>

<p>The expiration time for session resumption, either in tickets or stored data
is set using <a class="ref" href="#gnutls_005fdb_005fset_005fcache_005fexpiration">gnutls_db_set_cache_expiration</a>. This function also controls
the ticket key rotation period. Currently, the session key rotation interval is set
to 3 times the expiration time set by this function.
</p>
<p>Under TLS 1.3, the server sends by default 2 tickets, and can send
additional session tickets at any time using <a class="ref" href="#gnutls_005fsession_005fticket_005fsend">gnutls_session_ticket_send</a>.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsession_005fticket_005fsend"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_session_ticket_send</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, unsigned <var class="var">nr</var>, unsigned <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fsession_005fticket_005fsend"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">nr</var>: the number of tickets to send
</p>
<p><var class="var">flags</var>: must be zero
</p>
<p>Sends a fresh session ticket to the peer. This is relevant only
in server side under TLS1.3. This function may also return <code class="code">GNUTLS_E_AGAIN</code> 
or <code class="code">GNUTLS_E_INTERRUPTED</code>  and in that case it must be called again.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, or a negative error code.
</p></dd></dl>

<hr>
</div>
<div class="subsection-level-extent" id="Certificate-verification">
<div class="nav-panel">
<p>
Next: <a href="#TLS-1_002e2-re_002dauthentication" accesskey="n" rel="next">TLS 1.2 re-authentication</a>, Previous: <a href="#Session-resumption" accesskey="p" rel="prev">Session resumption</a>, Up: <a href="#Advanced-topics" accesskey="u" rel="up">Advanced topics</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Certificate-verification-1"><span>6.12.3 Certificate verification<a class="copiable-link" href="#Certificate-verification-1"> &para;</a></span></h4>
<a class="index-entry-id" id="index-DANE-1"></a>
<a class="index-entry-id" id="index-DNSSEC-1"></a>
<a class="index-entry-id" id="index-SSH_002dstyle-authentication-1"></a>
<a class="index-entry-id" id="index-Trust-on-first-use-1"></a>
<a class="index-entry-id" id="index-Key-pinning-1"></a>
<a class="index-entry-id" id="index-gnutls_005fcertificate_005fverify_005fflags-1"></a>

<p>In this section the functionality for additional certificate verification methods is listed.
These methods are intended to be used in addition to normal PKI verification, in order to reduce
the risk of a compromised CA being undetected.
</p>
<ul class="mini-toc">
<li><a href="#Trust-on-first-use" accesskey="1">Trust on first use</a></li>
<li><a href="#DANE-verification" accesskey="2">DANE verification</a></li>
</ul>
<div class="subsubsection-level-extent" id="Trust-on-first-use">
<h4 class="subsubsection"><span>6.12.3.1 Trust on first use<a class="copiable-link" href="#Trust-on-first-use"> &para;</a></span></h4>

<p>The GnuTLS library includes functionality to use an SSH-like trust on first use authentication.
The available functions to store and verify public keys are listed below.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fverify_005fstored_005fpubkey"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_verify_stored_pubkey</strong> <code class="def-code-arguments">(const char * <var class="var">db_name</var>, gnutls_tdb_t <var class="var">tdb</var>, const char * <var class="var">host</var>, const char * <var class="var">service</var>, gnutls_certificate_type_t <var class="var">cert_type</var>, const gnutls_datum_t * <var class="var">cert</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fverify_005fstored_005fpubkey"> &para;</a></span></dt>
<dd><p><var class="var">db_name</var>: A file specifying the stored keys (use NULL for the default)
</p>
<p><var class="var">tdb</var>: A storage structure or NULL to use the default
</p>
<p><var class="var">host</var>: The peer&rsquo;s name
</p>
<p><var class="var">service</var>: non-NULL if this key is specific to a service (e.g. http)
</p>
<p><var class="var">cert_type</var>: The type of the certificate
</p>
<p><var class="var">cert</var>: The raw (der) data of the certificate
</p>
<p><var class="var">flags</var>: should be 0.
</p>
<p>This function will try to verify a raw public-key or a public-key provided via
a raw (DER-encoded) certificate using a list of stored public keys.
The  <code class="code">service</code> field if non-NULL should be a port number.
</p>
<p>The  <code class="code">db_name</code> variable if non-null specifies a custom backend for
the retrieval of entries. If it is NULL then the
default file backend will be used. In POSIX-like systems the
file backend uses the $HOME/.gnutls/known_hosts file.
</p>
<p>Note that if the custom storage backend is provided the
retrieval function should return <code class="code">GNUTLS_E_CERTIFICATE_KEY_MISMATCH</code> 
if the host/service pair is found but key doesn&rsquo;t match,
<code class="code">GNUTLS_E_NO_CERTIFICATE_FOUND</code>  if no such host/service with
the given key is found, and 0 if it was found. The storage
function should return 0 on success.
</p>
<p>As of GnuTLS 3.6.6 this function also verifies raw public keys.
</p>
<p><strong class="strong">Returns:</strong> If no associated public key is found
then <code class="code">GNUTLS_E_NO_CERTIFICATE_FOUND</code>  will be returned. If a key
is found but does not match <code class="code">GNUTLS_E_CERTIFICATE_KEY_MISMATCH</code> 
is returned. On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
or a negative error value on other errors.
</p>
<p><strong class="strong">Since:</strong> 3.0.13
</p></dd></dl>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fstore_005fpubkey"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_store_pubkey</strong> <code class="def-code-arguments">(const char * <var class="var">db_name</var>, gnutls_tdb_t <var class="var">tdb</var>, const char * <var class="var">host</var>, const char * <var class="var">service</var>, gnutls_certificate_type_t <var class="var">cert_type</var>, const gnutls_datum_t * <var class="var">cert</var>, time_t <var class="var">expiration</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fstore_005fpubkey"> &para;</a></span></dt>
<dd><p><var class="var">db_name</var>: A file specifying the stored keys (use NULL for the default)
</p>
<p><var class="var">tdb</var>: A storage structure or NULL to use the default
</p>
<p><var class="var">host</var>: The peer&rsquo;s name
</p>
<p><var class="var">service</var>: non-NULL if this key is specific to a service (e.g. http)
</p>
<p><var class="var">cert_type</var>: The type of the certificate
</p>
<p><var class="var">cert</var>: The data of the certificate
</p>
<p><var class="var">expiration</var>: The expiration time (use 0 to disable expiration)
</p>
<p><var class="var">flags</var>: should be 0.
</p>
<p>This function will store a raw public-key or a public-key provided via
a raw (DER-encoded) certificate to the list of stored public keys. The key
will be considered valid until the provided expiration time.
</p>
<p>The  <code class="code">tdb</code> variable if non-null specifies a custom backend for
the storage of entries. If it is NULL then the
default file backend will be used.
</p>
<p>Unless an alternative  <code class="code">tdb</code> is provided, the storage format is a textual format
consisting of a line for each host with fields separated by &rsquo;|&rsquo;. The contents of
the fields are a format-identifier which is set to &rsquo;g0&rsquo;, the hostname that the
rest of the data applies to, the numeric port or host name, the expiration
time in seconds since the epoch (0 for no expiration), and a base64
encoding of the raw (DER) public key information (SPKI) of the peer.
</p>
<p>As of GnuTLS 3.6.6 this function also accepts raw public keys.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.0.13
</p></dd></dl>

<p>In addition to the above the <a class="ref" href="#gnutls_005fstore_005fcommitment">gnutls_store_commitment</a> can be
used to implement a key-pinning architecture as in [<a class="ref" href="#KEYPIN">KEYPIN</a>].
This provides a way for web server to commit on a public key that is
not yet active.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fstore_005fcommitment"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_store_commitment</strong> <code class="def-code-arguments">(const char * <var class="var">db_name</var>, gnutls_tdb_t <var class="var">tdb</var>, const char * <var class="var">host</var>, const char * <var class="var">service</var>, gnutls_digest_algorithm_t <var class="var">hash_algo</var>, const gnutls_datum_t * <var class="var">hash</var>, time_t <var class="var">expiration</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fstore_005fcommitment"> &para;</a></span></dt>
<dd><p><var class="var">db_name</var>: A file specifying the stored keys (use NULL for the default)
</p>
<p><var class="var">tdb</var>: A storage structure or NULL to use the default
</p>
<p><var class="var">host</var>: The peer&rsquo;s name
</p>
<p><var class="var">service</var>: non-NULL if this key is specific to a service (e.g. http)
</p>
<p><var class="var">hash_algo</var>: The hash algorithm type
</p>
<p><var class="var">hash</var>: The raw hash
</p>
<p><var class="var">expiration</var>: The expiration time (use 0 to disable expiration)
</p>
<p><var class="var">flags</var>: should be 0 or <code class="code">GNUTLS_SCOMMIT_FLAG_ALLOW_BROKEN</code> .
</p>
<p>This function will store the provided hash commitment to
the list of stored public keys. The key with the given
hash will be considered valid until the provided expiration time.
</p>
<p>The  <code class="code">tdb</code> variable if non-null specifies a custom backend for
the storage of entries. If it is NULL then the
default file backend will be used.
</p>
<p>Note that this function is not thread safe with the default backend.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<p>The storage and verification functions may be used with the default
text file based back-end, or another back-end may be specified. That
should contain storage and retrieval functions and specified as below.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005ftdb_005finit">gnutls_tdb_init</a> (gnutls_tdb_t * <var class="var">tdb</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005ftdb_005fdeinit">gnutls_tdb_deinit</a> (gnutls_tdb_t <var class="var">tdb</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005ftdb_005fset_005fverify_005ffunc">gnutls_tdb_set_verify_func</a> (gnutls_tdb_t <var class="var">tdb</var>, gnutls_tdb_verify_func <var class="var">verify</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005ftdb_005fset_005fstore_005ffunc">gnutls_tdb_set_store_func</a> (gnutls_tdb_t <var class="var">tdb</var>, gnutls_tdb_store_func <var class="var">store</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005ftdb_005fset_005fstore_005fcommitment_005ffunc">gnutls_tdb_set_store_commitment_func</a> (gnutls_tdb_t <var class="var">tdb</var>, gnutls_tdb_store_commitment_func <var class="var">cstore</var>)</code></dt>
</dl>

</div>
<div class="subsubsection-level-extent" id="DANE-verification">
<h4 class="subsubsection"><span>6.12.3.2 DANE verification<a class="copiable-link" href="#DANE-verification"> &para;</a></span></h4>
<p>Since the DANE library is not included in GnuTLS it requires programs
to be linked against it. This can be achieved with the following commands.
</p>
<div class="example">
<pre class="example-preformatted">gcc -o foo foo.c `pkg-config gnutls-dane --cflags --libs`
</pre></div>

<p>When a program uses the GNU autoconf system, then the following
line or similar can be used to detect the presence of the library.
</p>
<div class="example">
<pre class="example-preformatted">PKG_CHECK_MODULES([LIBDANE], [gnutls-dane &gt;= 3.0.0])

AC_SUBST([LIBDANE_CFLAGS])
AC_SUBST([LIBDANE_LIBS])
</pre></div>

<p>The high level functionality provided by the DANE library is shown below.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-dane_005fverify_005fcrt"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">dane_verify_crt</strong> <code class="def-code-arguments">(dane_state_t <var class="var">s</var>, const gnutls_datum_t * <var class="var">chain</var>, unsigned <var class="var">chain_size</var>, gnutls_certificate_type_t <var class="var">chain_type</var>, const char * <var class="var">hostname</var>, const char * <var class="var">proto</var>, unsigned int <var class="var">port</var>, unsigned int <var class="var">sflags</var>, unsigned int <var class="var">vflags</var>, unsigned int * <var class="var">verify</var>)</code><a class="copiable-link" href="#index-dane_005fverify_005fcrt"> &para;</a></span></dt>
<dd><p><var class="var">s</var>: A DANE state structure (may be NULL)
</p>
<p><var class="var">chain</var>: A certificate chain
</p>
<p><var class="var">chain_size</var>: The size of the chain
</p>
<p><var class="var">chain_type</var>: The type of the certificate chain
</p>
<p><var class="var">hostname</var>: The hostname associated with the chain
</p>
<p><var class="var">proto</var>: The protocol of the service connecting (e.g. tcp)
</p>
<p><var class="var">port</var>: The port of the service connecting (e.g. 443)
</p>
<p><var class="var">sflags</var>: Flags for the initialization of  <code class="code">s</code> (if NULL)
</p>
<p><var class="var">vflags</var>: Verification flags; an OR&rsquo;ed list of <code class="code">dane_verify_flags_t</code> .
</p>
<p><var class="var">verify</var>: An OR&rsquo;ed list of <code class="code">dane_verify_status_t</code> .
</p>
<p>This function will verify the given certificate chain against the
CA constrains and/or the certificate available via DANE.
If no information via DANE can be obtained the flag <code class="code">DANE_VERIFY_NO_DANE_INFO</code> 
is set. If a DNSSEC signature is not available for the DANE
record then the verify flag <code class="code">DANE_VERIFY_NO_DNSSEC_DATA</code>  is set.
</p>
<p>Due to the many possible options of DANE, there is no single threat
model countered. When notifying the user about DANE verification results
it may be better to mention: DANE verification did not reject the certificate,
rather than mentioning a successful DANE verification.
</p>
<p>Note that this function is designed to be run in addition to
PKIX - certificate chain - verification. To be run independently
the <code class="code">DANE_VFLAG_ONLY_CHECK_EE_USAGE</code>  flag should be specified;
then the function will check whether the key of the peer matches the
key advertised in the DANE entry.
</p>
<p><strong class="strong">Returns:</strong> a negative error code on error and <code class="code">DANE_E_SUCCESS</code>  (0)
when the DANE entries were successfully parsed, irrespective of
whether they were verified (see  <code class="code">verify</code> for that information). If
no usable entries were encountered <code class="code">DANE_E_REQUESTED_DATA_NOT_AVAILABLE</code> 
will be returned.
</p></dd></dl>

<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#dane_005fverify_005fsession_005fcrt">dane_verify_session_crt</a> (dane_state_t <var class="var">s</var>, gnutls_session_t <var class="var">session</var>, const char * <var class="var">hostname</var>, const char * <var class="var">proto</var>, unsigned int <var class="var">port</var>, unsigned int <var class="var">sflags</var>, unsigned int <var class="var">vflags</var>, unsigned int * <var class="var">verify</var>)</code></dt>
<dt><code class="code"><var class="var">const char *</var> <a class="ref" href="#dane_005fstrerror">dane_strerror</a> (int <var class="var">error</var>)</code></dt>
</dl>

<p>Note that the <code class="code">dane_state_t</code> structure that is accepted by both
verification functions is optional. It is required when many queries
are performed to optimize against multiple re-initializations of the
resolving back-end and loading of DNSSEC keys.
</p>
<p>The following flags are returned by the verify functions to
indicate the status of the verification.
</p>
<div class="float" id="dane_005fverify_005fstatus_005ft">


<dl class="table">
<dt><code class="code">DANE_VERIFY_CA_CONSTRAINTS_VIOLATED</code></dt>
<dd><p>The CA constraints were violated.
</p></dd>
<dt><code class="code">DANE_VERIFY_CERT_DIFFERS</code></dt>
<dd><p>The certificate obtained via DNS differs.
</p></dd>
<dt><code class="code">DANE_VERIFY_UNKNOWN_DANE_INFO</code></dt>
<dd><p>No known DANE data was found in the DNS record.
</p></dd>
</dl>
<div class="caption"><p><strong class="strong">Figure 6.3: </strong>The DANE verification status flags.</p></div></div>
<p>In order to generate a DANE TLSA entry to use in a DNS server
you may use danetool (see <a class="ref" href="#danetool-Invocation">Invoking danetool</a>).
</p>


<hr>
</div>
</div>
<div class="subsection-level-extent" id="TLS-1_002e2-re_002dauthentication">
<div class="nav-panel">
<p>
Next: <a href="#TLS-1_002e3-re_002dauthentication-and-re_002dkey" accesskey="n" rel="next">TLS 1.3 re-authentication and re-key</a>, Previous: <a href="#Certificate-verification" accesskey="p" rel="prev">Certificate verification</a>, Up: <a href="#Advanced-topics" accesskey="u" rel="up">Advanced topics</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="TLS-1_002e2-re_002dauthentication-1"><span>6.12.4 TLS 1.2 re-authentication<a class="copiable-link" href="#TLS-1_002e2-re_002dauthentication-1"> &para;</a></span></h4>
<a class="index-entry-id" id="index-re_002dnegotiation"></a>
<a class="index-entry-id" id="index-re_002dauthentication"></a>

<p>In TLS 1.2 or earlier there is no distinction between re-key, re-authentication, and re-negotiation.
All of these use cases are handled by the TLS&rsquo; rehandshake process. For that reason
in GnuTLS rehandshake is not transparent to the application, and the application
must explicitly take control of that process. In addition GnuTLS since version 3.5.0 will not
allow the peer to switch identities during a rehandshake.
The threat addressed by that behavior depends on the application protocol,
but primarily it protects applications from being misled
by a rehandshake which switches the peer&rsquo;s identity. Applications can
disable this protection by using the <code class="code">GNUTLS_ALLOW_ID_CHANGE</code> flag in
<a class="ref" href="#gnutls_005finit">gnutls_init</a>.
</p>
<p>The following paragraphs explain how to safely use the rehandshake process.
</p>
<ul class="mini-toc">
<li><a href="#Client-side" accesskey="1">Client side</a></li>
<li><a href="#Server-side" accesskey="2">Server side</a></li>
</ul>
<div class="subsubsection-level-extent" id="Client-side">
<h4 class="subsubsection"><span>6.12.4.1 Client side<a class="copiable-link" href="#Client-side"> &para;</a></span></h4>

<p>According to the TLS specification a client may initiate a rehandshake at any
time. That can be achieved by calling <a class="ref" href="#gnutls_005fhandshake">gnutls_handshake</a> and rely on its
return value for the outcome of the handshake (the server may deny a rehandshake).
If a server requests a re-handshake, then a call to <a class="ref" href="#gnutls_005frecord_005frecv">gnutls_record_recv</a> will
return GNUTLS_E_REHANDSHAKE in the client, instructing it to call <a class="ref" href="#gnutls_005fhandshake">gnutls_handshake</a>.
To deny a rehandshake request by the server it is recommended to send a warning alert
of type GNUTLS_A_NO_RENEGOTIATION.
</p>
<p>Due to limitations of early protocol versions, it is required to check whether
safe renegotiation is in place, i.e., using <a class="ref" href="#gnutls_005fsafe_005frenegotiation_005fstatus">gnutls_safe_renegotiation_status</a>,
which ensures that the server remains the same as the initial.
</p>
<p>To make re-authentication transparent to the application when requested
by the server, use the <code class="code">GNUTLS_AUTO_REAUTH</code> flag on the
<a class="ref" href="#gnutls_005finit">gnutls_init</a> call. In that case the re-authentication will happen
in the call of <a class="ref" href="#gnutls_005frecord_005frecv">gnutls_record_recv</a> that received the
reauthentication request.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsafe_005frenegotiation_005fstatus"><span class="category-def">Function: </span><span><code class="def-type">unsigned</code> <strong class="def-name">gnutls_safe_renegotiation_status</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fsafe_005frenegotiation_005fstatus"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>Can be used to check whether safe renegotiation is being used
in the current session.
</p>
<p><strong class="strong">Returns:</strong> 0 when safe renegotiation is not used and non (0) when
safe renegotiation is used.
</p>
<p><strong class="strong">Since:</strong> 2.10.0
</p></dd></dl>

</div>
<div class="subsubsection-level-extent" id="Server-side">
<h4 class="subsubsection"><span>6.12.4.2 Server side<a class="copiable-link" href="#Server-side"> &para;</a></span></h4>

<p>A server which wants to instruct the client to re-authenticate, should call
<a class="ref" href="#gnutls_005frehandshake">gnutls_rehandshake</a> and wait for the client to re-authenticate.
It is recommended to only request re-handshake when safe renegotiation is
enabled for that session (see <a class="ref" href="#gnutls_005fsafe_005frenegotiation_005fstatus">gnutls_safe_renegotiation_status</a> and
the discussion in <a class="ref" href="#Safe-renegotiation">Safe renegotiation</a>). A server could also encounter
the GNUTLS_E_REHANDSHAKE error code while receiving data. That indicates
a client-initiated re-handshake request. In that case the server could
ignore that request, perform handshake (unsafe when done generally), or
even drop the connection.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frehandshake"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_rehandshake</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005frehandshake"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>This function can only be called in server side, and
instructs a TLS 1.2 or earlier client to renegotiate
parameters (perform a handshake), by sending a
hello request message.
</p>
<p>If this function succeeds, the calling application
should call <code class="code">gnutls_record_recv()</code>  until <code class="code">GNUTLS_E_REHANDSHAKE</code> 
is returned to clear any pending data. If the <code class="code">GNUTLS_E_REHANDSHAKE</code> 
error code is not seen, then the handshake request was
not followed by the peer (the TLS protocol does not require
the client to do, and such compliance should be handled
by the application protocol).
</p>
<p>Once the <code class="code">GNUTLS_E_REHANDSHAKE</code>  error code is seen, the
calling application should proceed to calling
<code class="code">gnutls_handshake()</code>  to negotiate the new
parameters.
</p>
<p>If the client does not wish to renegotiate parameters he
may reply with an alert message, and in that case the return code seen
by subsequent <code class="code">gnutls_record_recv()</code>  will be
<code class="code">GNUTLS_E_WARNING_ALERT_RECEIVED</code>  with the specific alert being
<code class="code">GNUTLS_A_NO_RENEGOTIATION</code> .  A client may also choose to ignore
this request.
</p>
<p>Under TLS 1.3 this function is equivalent to <code class="code">gnutls_session_key_update()</code> 
with the <code class="code">GNUTLS_KU_PEER</code>  flag. In that case subsequent calls to
<code class="code">gnutls_record_recv()</code>  will not return <code class="code">GNUTLS_E_REHANDSHAKE</code> , and
calls to <code class="code">gnutls_handshake()</code>  in server side are a no-op.
</p>
<p>This function always fails with <code class="code">GNUTLS_E_INVALID_REQUEST</code>  when
called in client side.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p></dd></dl>

<hr>
</div>
</div>
<div class="subsection-level-extent" id="TLS-1_002e3-re_002dauthentication-and-re_002dkey">
<div class="nav-panel">
<p>
Next: <a href="#Parameter-generation" accesskey="n" rel="next">Parameter generation</a>, Previous: <a href="#TLS-1_002e2-re_002dauthentication" accesskey="p" rel="prev">TLS 1.2 re-authentication</a>, Up: <a href="#Advanced-topics" accesskey="u" rel="up">Advanced topics</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="TLS-1_002e3-re_002dauthentication-and-re_002dkey-1"><span>6.12.5 TLS 1.3 re-authentication and re-key<a class="copiable-link" href="#TLS-1_002e3-re_002dauthentication-and-re_002dkey-1"> &para;</a></span></h4>
<a class="index-entry-id" id="index-re_002dkey"></a>
<a class="index-entry-id" id="index-re_002dnegotiation-1"></a>
<a class="index-entry-id" id="index-re_002dauthentication-1"></a>
<a class="index-entry-id" id="index-post_002dhandshake-authentication"></a>

<p>The TLS 1.3 protocol distinguishes between re-key and re-authentication.
The re-key process ensures that fresh keys are supplied to the already
negotiated parameters, and on GnuTLS can be initiated using
<a class="ref" href="#gnutls_005fsession_005fkey_005fupdate">gnutls_session_key_update</a>. The re-key process can be one-way
(i.e., the calling party only changes its keys), or two-way where the peer
is requested to change keys as well.
</p>
<p>The re-authentication process, allows the connected client to switch
identity by presenting a new certificate. Unlike TLS 1.2, the server
is not allowed to change identities. That client re-authentication, or
post-handshake authentication can be initiated only by the server using
<a class="ref" href="#gnutls_005freauth">gnutls_reauth</a>, and only if a client has advertised support for it.
Both server and client have to explicitly enable support for post handshake
authentication using the <code class="code">GNUTLS_POST_HANDSHAKE_AUTH</code> flag at <a class="ref" href="#gnutls_005finit">gnutls_init</a>.
</p>
<p>A client receiving a re-authentication request will &quot;see&quot; the error code
<code class="code">GNUTLS_E_REAUTH_REQUEST</code> at <a class="ref" href="#gnutls_005frecord_005frecv">gnutls_record_recv</a>. At this
point, it should also call <a class="ref" href="#gnutls_005freauth">gnutls_reauth</a>.
</p>
<p>To make re-authentication transparent to the application when requested
by the server, use the <code class="code">GNUTLS_AUTO_REAUTH</code> and <code class="code">GNUTLS_POST_HANDSHAKE_AUTH</code>
flags on the <a class="ref" href="#gnutls_005finit">gnutls_init</a> call. In that case the re-authentication will happen
in the call of <a class="ref" href="#gnutls_005frecord_005frecv">gnutls_record_recv</a> that received the
reauthentication request.
</p>
<hr>
</div>
<div class="subsection-level-extent" id="Parameter-generation">
<div class="nav-panel">
<p>
Next: <a href="#Deriving-keys-for-other-applications_002fprotocols" accesskey="n" rel="next">Deriving keys for other applications/protocols</a>, Previous: <a href="#TLS-1_002e3-re_002dauthentication-and-re_002dkey" accesskey="p" rel="prev">TLS 1.3 re-authentication and re-key</a>, Up: <a href="#Advanced-topics" accesskey="u" rel="up">Advanced topics</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Parameter-generation-1"><span>6.12.6 Parameter generation<a class="copiable-link" href="#Parameter-generation-1"> &para;</a></span></h4>
<a class="index-entry-id" id="index-parameter-generation"></a>
<a class="index-entry-id" id="index-generating-parameters"></a>

<p>Prior to GnuTLS 3.6.0 for the ephemeral or anonymous Diffie-Hellman (DH) TLS ciphersuites
the application was required to generate or provide
DH parameters. That is no longer necessary as GnuTLS utilizes DH parameters
and negotiation from [<a class="ref" href="#RFC7919">RFC7919</a>].
</p>
<p>Applications can tune the used parameters by explicitly specifying them
in the priority string. In server side applications can set the
minimum acceptable level of DH parameters by calling
<a class="ref" href="#gnutls_005fcertificate_005fset_005fknown_005fdh_005fparams">gnutls_certificate_set_known_dh_params</a>,
<a class="ref" href="#gnutls_005fanon_005fset_005fserver_005fknown_005fdh_005fparams">gnutls_anon_set_server_known_dh_params</a>, or
<a class="ref" href="#gnutls_005fpsk_005fset_005fserver_005fknown_005fdh_005fparams">gnutls_psk_set_server_known_dh_params</a>, depending on the type
of the credentials, to set the lower acceptable parameter limits. Typical
applications should rely on the default settings.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fcertificate_005fset_005fknown_005fdh_005fparams">gnutls_certificate_set_known_dh_params</a> (gnutls_certificate_credentials_t <var class="var">res</var>, gnutls_sec_param_t <var class="var">sec_param</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fanon_005fset_005fserver_005fknown_005fdh_005fparams">gnutls_anon_set_server_known_dh_params</a> (gnutls_anon_server_credentials_t <var class="var">res</var>, gnutls_sec_param_t <var class="var">sec_param</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpsk_005fset_005fserver_005fknown_005fdh_005fparams">gnutls_psk_set_server_known_dh_params</a> (gnutls_psk_server_credentials_t <var class="var">res</var>, gnutls_sec_param_t <var class="var">sec_param</var>)</code></dt>
</dl>


<ul class="mini-toc">
<li><a href="#Legacy-parameter-generation" accesskey="1">Legacy parameter generation</a></li>
</ul>
<div class="subsubsection-level-extent" id="Legacy-parameter-generation">
<h4 class="subsubsection"><span>6.12.6.1 Legacy parameter generation<a class="copiable-link" href="#Legacy-parameter-generation"> &para;</a></span></h4>
<p>Note that older than 3.5.6 versions of GnuTLS provided functions
to generate or import arbitrary DH parameters from a file. This
practice is still supported but discouraged in current versions.
There is no known advantage from using random parameters, while there
have been several occasions where applications were utilizing incorrect,
weak or insecure parameters. This is the main reason GnuTLS includes the
well-known parameters of [<a class="ref" href="#RFC7919">RFC7919</a>] and recommends applications
utilizing them.
</p>
<p>In older applications which require to specify explicit DH parameters, we recommend
using <code class="code">certtool</code> (of GnuTLS 3.5.6 or later) with the <code class="code">--get-dh-params</code>
option to obtain the FFDHE parameters discussed above. The output
parameters of the tool are in PKCS#3 format and can be imported by
most existing applications.
</p>
<p>The following functions are still supported but considered obsolete.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fdh_005fparams_005fgenerate2">gnutls_dh_params_generate2</a> (gnutls_dh_params_t <var class="var">dparams</var>, unsigned int <var class="var">bits</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fdh_005fparams_005fimport_005fpkcs3">gnutls_dh_params_import_pkcs3</a> (gnutls_dh_params_t <var class="var">params</var>, const gnutls_datum_t * <var class="var">pkcs3_params</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fcertificate_005fset_005fdh_005fparams">gnutls_certificate_set_dh_params</a> (gnutls_certificate_credentials_t <var class="var">res</var>, gnutls_dh_params_t <var class="var">dh_params</var>)</code></dt>
</dl>


<hr>
</div>
</div>
<div class="subsection-level-extent" id="Deriving-keys-for-other-applications_002fprotocols">
<div class="nav-panel">
<p>
Next: <a href="#Channel-Bindings" accesskey="n" rel="next">Channel bindings</a>, Previous: <a href="#Parameter-generation" accesskey="p" rel="prev">Parameter generation</a>, Up: <a href="#Advanced-topics" accesskey="u" rel="up">Advanced topics</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Deriving-keys-for-other-applications_002fprotocols-1"><span>6.12.7 Deriving keys for other applications/protocols<a class="copiable-link" href="#Deriving-keys-for-other-applications_002fprotocols-1"> &para;</a></span></h4>
<a class="index-entry-id" id="index-keying-material-exporters"></a>
<a class="index-entry-id" id="index-exporting-keying-material"></a>
<a class="index-entry-id" id="index-deriving-keys"></a>
<a class="index-entry-id" id="index-key-extraction"></a>

<p>In several cases, after a TLS connection is established, it is desirable
to derive keys to be used in another application or protocol (e.g., in an
other TLS session using pre-shared keys). The following describe GnuTLS&rsquo;
implementation of RFC5705 to extract keys based on a session&rsquo;s master secret.
</p>
<p>The API to use is <a class="ref" href="#gnutls_005fprf_005frfc5705">gnutls_prf_rfc5705</a>.  The
function needs to be provided with a label,
and additional context data to mix in the <code class="code">context</code> parameter.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprf_005frfc5705"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_prf_rfc5705</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, size_t <var class="var">label_size</var>, const char * <var class="var">label</var>, size_t <var class="var">context_size</var>, const char * <var class="var">context</var>, size_t <var class="var">outsize</var>, char * <var class="var">out</var>)</code><a class="copiable-link" href="#index-gnutls_005fprf_005frfc5705"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">label_size</var>: length of the  <code class="code">label</code> variable.
</p>
<p><var class="var">label</var>: label used in PRF computation, typically a short string.
</p>
<p><var class="var">context_size</var>: length of the  <code class="code">extra</code> variable.
</p>
<p><var class="var">context</var>: optional extra data to seed the PRF with.
</p>
<p><var class="var">outsize</var>: size of pre-allocated output buffer to hold the output.
</p>
<p><var class="var">out</var>: pre-allocated buffer to hold the generated data.
</p>
<p>Exports keying material from TLS/DTLS session to an application, as
specified in RFC5705.
</p>
<p>In the TLS versions prior to 1.3, it applies the TLS
Pseudo-Random-Function (PRF) on the master secret and the provided
data, seeded with the client and server random fields.
</p>
<p>In TLS 1.3, it applies HKDF on the exporter master secret derived
from the master secret.
</p>
<p>The  <code class="code">label</code> variable usually contains a string denoting the purpose
for the generated data.
</p>
<p>The  <code class="code">context</code> variable can be used to add more data to the seed, after
the random variables.  It can be used to make sure the
generated output is strongly connected to some additional data
(e.g., a string used in user authentication). 
</p>
<p>The output is placed in  <code class="code">out</code> , which must be pre-allocated.
</p>
<p>Note that, to provide the RFC5705 context, the  <code class="code">context</code> variable
must be non-null.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, or an error code.
</p>
<p><strong class="strong">Since:</strong> 3.4.4
</p></dd></dl>

<p>For example, after establishing a TLS session using
<a class="ref" href="#gnutls_005fhandshake">gnutls_handshake</a>, you can obtain 32-bytes to be used as key, using this call:
</p>
<div class="example">
<pre class="example-preformatted">#define MYLABEL &quot;EXPORTER-My-protocol-name&quot;
#define MYCONTEXT &quot;my-protocol's-1st-session&quot;

char out[32];
rc = gnutls_prf_rfc5705 (session, sizeof(MYLABEL)-1, MYLABEL,
                         sizeof(MYCONTEXT)-1, MYCONTEXT, 32, out);
</pre></div>

<p>The output key depends on TLS&rsquo; master secret, and is the same on both client
and server.
</p>
<p>For legacy applications which need to use a more flexible API, there is
<a class="ref" href="#gnutls_005fprf">gnutls_prf</a>, which in addition, allows to switch the mix of the
client and server random nonces, using the <code class="code">server_random_first</code> parameter.
For additional flexibility and low-level access to the TLS1.2 PRF,
there is a low-level TLS PRF interface called <a class="ref" href="#gnutls_005fprf_005fraw">gnutls_prf_raw</a>.
That however is not functional under newer protocol versions.
</p>
<hr>
</div>
<div class="subsection-level-extent" id="Channel-Bindings">
<div class="nav-panel">
<p>
Next: <a href="#Interoperability" accesskey="n" rel="next">Interoperability</a>, Previous: <a href="#Deriving-keys-for-other-applications_002fprotocols" accesskey="p" rel="prev">Deriving keys for other applications/protocols</a>, Up: <a href="#Advanced-topics" accesskey="u" rel="up">Advanced topics</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Channel-bindings"><span>6.12.8 Channel bindings<a class="copiable-link" href="#Channel-bindings"> &para;</a></span></h4>
<a class="index-entry-id" id="index-channel-bindings"></a>

<p>In user authentication protocols (e.g., EAP or SASL mechanisms) it is
useful to have a unique string that identifies the secure channel that
is used, to bind together the user authentication with the secure
channel.  This can protect against man-in-the-middle attacks in some
situations.  That unique string is called a &ldquo;channel binding&rdquo;.  For
background and discussion see [<a class="ref" href="#RFC5056">RFC5056</a>].
</p>
<p>In <abbr class="acronym">GnuTLS</abbr> you can extract a channel binding using the
<a class="ref" href="#gnutls_005fsession_005fchannel_005fbinding">gnutls_session_channel_binding</a> function.  Currently only the
following types are supported:
</p>
<ul class="itemize mark-bullet">
<li><code class="code">GNUTLS_CB_TLS_UNIQUE</code>: corresponds to the <code class="code">tls-unique</code> channel binding for TLS defined in [<a class="ref" href="#RFC5929">RFC5929</a>]
</li><li><code class="code">GNUTLS_CB_TLS_EXPORTER</code>: corresponds to the <code class="code">tls-exporter</code> channel binding for TLS defined in [<a class="ref" href="#RFC9266">RFC9266</a>]
</li></ul>

<p>The following example describes how to print the channel binding data.
Note that it must be run after a successful TLS handshake.
</p>
<div class="example">
<pre class="example-preformatted">{
  gnutls_datum_t cb;
  int rc;

  rc = gnutls_session_channel_binding (session,
                                       GNUTLS_CB_TLS_UNIQUE,
                                       &amp;cb);
  if (rc)
    fprintf (stderr, &quot;Channel binding error: %s\n&quot;,
             gnutls_strerror (rc));
  else
    {
      size_t i;
      printf (&quot;- Channel binding 'tls-unique': &quot;);
      for (i = 0; i &lt; cb.size; i++)
        printf (&quot;%02x&quot;, cb.data[i]);
      printf (&quot;\n&quot;);
    }
}
</pre></div>

<hr>
</div>
<div class="subsection-level-extent" id="Interoperability">
<div class="nav-panel">
<p>
Next: <a href="#Compatibility-with-the-OpenSSL-library" accesskey="n" rel="next">Compatibility with the OpenSSL library</a>, Previous: <a href="#Channel-Bindings" accesskey="p" rel="prev">Channel bindings</a>, Up: <a href="#Advanced-topics" accesskey="u" rel="up">Advanced topics</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Interoperability-1"><span>6.12.9 Interoperability<a class="copiable-link" href="#Interoperability-1"> &para;</a></span></h4>

<p>The <abbr class="acronym">TLS</abbr> protocols support many ciphersuites, extensions and version
numbers. As a result, few implementations are
not able to properly interoperate once faced with extensions or version protocols
they do not support and understand. The <abbr class="acronym">TLS</abbr> protocol allows for a
graceful downgrade to the commonly supported options, but practice shows
it is not always implemented correctly.
</p>
<p>Because there is no way to achieve maximum interoperability with broken peers
without sacrificing security, <abbr class="acronym">GnuTLS</abbr> ignores such peers by default.
This might not be acceptable in cases where maximum compatibility
is required. Thus we allow enabling compatibility with broken peers using
priority strings (see <a class="ref" href="#Priority-Strings">Priority strings</a>). A conservative priority
string that would disable certain <abbr class="acronym">TLS</abbr> protocol
options that are known to cause compatibility problems, is shown below.
</p><pre class="verbatim">NORMAL:%COMPAT
</pre>
<p>For very old broken peers that do not tolerate TLS version numbers over TLS 1.0
another priority string is:
</p><pre class="verbatim">NORMAL:-VERS-ALL:+VERS-TLS1.0:+VERS-SSL3.0:%COMPAT
</pre><p>This priority string will in addition to above, only enable SSL 3.0 and
TLS 1.0 as protocols.
</p>

<hr>
</div>
<div class="subsection-level-extent" id="Compatibility-with-the-OpenSSL-library">
<div class="nav-panel">
<p>
Previous: <a href="#Interoperability" accesskey="p" rel="prev">Interoperability</a>, Up: <a href="#Advanced-topics" accesskey="u" rel="up">Advanced topics</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Compatibility-with-the-OpenSSL-library-1"><span>6.12.10 Compatibility with the OpenSSL library<a class="copiable-link" href="#Compatibility-with-the-OpenSSL-library-1"> &para;</a></span></h4>
<a class="index-entry-id" id="index-OpenSSL"></a>

<p>To ease <abbr class="acronym">GnuTLS</abbr>&rsquo; integration with existing applications, a
compatibility layer with the OpenSSL library is included
in the <code class="code">gnutls-openssl</code> library. This compatibility layer is not
complete and it is not intended to completely re-implement the OpenSSL
API with <abbr class="acronym">GnuTLS</abbr>.  It only provides limited source-level
compatibility.
</p>
<p>The prototypes for the compatibility functions are in the
<samp class="file">gnutls/openssl.h</samp> header file. The limitations
imposed by the compatibility layer include:
</p>
<ul class="itemize mark-bullet">
<li>Error handling is not thread safe.

</li></ul>


<hr>
</div>
</div>
</div>
<div class="chapter-level-extent" id="GnuTLS-application-examples">
<div class="nav-panel">
<p>
Next: <a href="#System_002dwide-configuration-of-the-library" accesskey="n" rel="next">System-wide configuration of the library</a>, Previous: <a href="#How-to-use-GnuTLS-in-applications" accesskey="p" rel="prev">How to use <abbr class="acronym">GnuTLS</abbr> in applications</a>, Up: <a href="#Top" accesskey="u" rel="up">GnuTLS</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h2 class="chapter" id="GnuTLS-application-examples-1"><span>7 GnuTLS application examples<a class="copiable-link" href="#GnuTLS-application-examples-1"> &para;</a></span></h2>
<a class="anchor" id="examples"></a><a class="index-entry-id" id="index-example-programs"></a>
<a class="index-entry-id" id="index-examples"></a>

<p>In this chapter several examples of real-world use cases are listed.
The examples are simplified to promote readability and contain little or 
no error checking.  
</p>

<ul class="mini-toc">
<li><a href="#Client-examples" accesskey="1">Client examples</a></li>
<li><a href="#Server-examples" accesskey="2">Server examples</a></li>
<li><a href="#More-advanced-client-and-servers" accesskey="3">More advanced client and servers</a></li>
<li><a href="#OCSP-example" accesskey="4">OCSP example</a></li>
<li><a href="#Miscellaneous-examples" accesskey="5">Miscellaneous examples</a></li>
</ul>
<hr>
<div class="section-level-extent" id="Client-examples">
<div class="nav-panel">
<p>
Next: <a href="#Server-examples" accesskey="n" rel="next">Server examples</a>, Up: <a href="#GnuTLS-application-examples" accesskey="u" rel="up">GnuTLS application examples</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Client-examples-1"><span>7.1 Client examples<a class="copiable-link" href="#Client-examples-1"> &para;</a></span></h3>

<p>This section contains examples of <abbr class="acronym">TLS</abbr> and <abbr class="acronym">SSL</abbr>
clients, using <abbr class="acronym">GnuTLS</abbr>. Note that some of the examples require functions
implemented by another example.
</p>

<ul class="mini-toc">
<li><a href="#Client-example-with-X_002e509-certificate-support" accesskey="1">Client example with <abbr class="acronym">X.509</abbr> certificate support</a></li>
<li><a href="#Datagram-TLS-client-example" accesskey="2">Datagram <abbr class="acronym">TLS</abbr> client example</a></li>
<li><a href="#Client-using-a-smart-card-with-TLS" accesskey="3">Using a smart card with TLS</a></li>
<li><a href="#Client-with-Resume-capability-example" accesskey="4">Client with resume capability example</a></li>
<li><a href="#Client-example-with-SSH_002dstyle-certificate-verification" accesskey="5">Client example with SSH-style certificate verification</a></li>
</ul>
<hr>
<div class="subsection-level-extent" id="Client-example-with-X_002e509-certificate-support">
<div class="nav-panel">
<p>
Next: <a href="#Datagram-TLS-client-example" accesskey="n" rel="next">Datagram <abbr class="acronym">TLS</abbr> client example</a>, Up: <a href="#Client-examples" accesskey="u" rel="up">Client examples</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Client-example-with-X_002e509-certificate-support-1"><span>7.1.1 Client example with <abbr class="acronym">X.509</abbr> certificate support<a class="copiable-link" href="#Client-example-with-X_002e509-certificate-support-1"> &para;</a></span></h4>
<a class="anchor" id="ex_002dverify"></a>
<p>Let&rsquo;s assume now that we want to create a TCP client which
communicates with servers that use <abbr class="acronym">X.509</abbr> certificate authentication.
The following client is a very simple <abbr class="acronym">TLS</abbr> client, which uses
the high level verification functions for certificates, but does not support session
resumption.
</p>
<p>Note that this client utilizes functionality present in the latest GnuTLS
version. For a reasonably portable version see <a class="ref" href="#Legacy-client-example-with-X_002e509-certificate-support">Legacy client example with <abbr class="acronym">X.509</abbr> certificate support</a>.
</p>
<pre class="verbatim">/* This example code is placed in the public domain. */

#ifdef HAVE_CONFIG_H
#include &lt;config.h&gt;
#endif

#include &lt;stdio.h&gt;
#include &lt;stdlib.h&gt;
#include &lt;string.h&gt;
#include &lt;assert.h&gt;
#include &lt;gnutls/gnutls.h&gt;
#include &lt;gnutls/x509.h&gt;
#include &quot;examples.h&quot;

/* A very basic TLS client, with X.509 authentication and server certificate
 * verification. Note that error recovery is minimal for simplicity.
 */

#define CHECK(x) assert((x) &gt;= 0)
#define LOOP_CHECK(rval, cmd)                                             \
	do {                                                              \
		rval = cmd;                                               \
	} while (rval == GNUTLS_E_AGAIN || rval == GNUTLS_E_INTERRUPTED); \
	assert(rval &gt;= 0)

#define MAX_BUF 1024
#define MSG &quot;GET / HTTP/1.0\r\n\r\n&quot;

extern int tcp_connect(void);
extern void tcp_close(int sd);

int main(void)
{
	int ret, sd, ii;
	gnutls_session_t session;
	char buffer[MAX_BUF + 1], *desc;
	gnutls_datum_t out;
	int type;
	unsigned status;
	gnutls_certificate_credentials_t xcred;

	if (gnutls_check_version(&quot;3.4.6&quot;) == NULL) {
		fprintf(stderr,
			&quot;GnuTLS 3.4.6 or later is required for this example\n&quot;);
		exit(1);
	}

	/* for backwards compatibility with gnutls &lt; 3.3.0 */
	CHECK(gnutls_global_init());

	/* X509 stuff */
	CHECK(gnutls_certificate_allocate_credentials(&amp;xcred));

	/* sets the system trusted CAs for Internet PKI */
	CHECK(gnutls_certificate_set_x509_system_trust(xcred));

	/* If client holds a certificate it can be set using the following:
	 *
	 gnutls_certificate_set_x509_key_file (xcred, &quot;cert.pem&quot;, &quot;key.pem&quot;, 
	 GNUTLS_X509_FMT_PEM); 
	 */

	/* Initialize TLS session */
	CHECK(gnutls_init(&amp;session, GNUTLS_CLIENT));

	CHECK(gnutls_server_name_set(session, GNUTLS_NAME_DNS,
				     &quot;www.example.com&quot;,
				     strlen(&quot;www.example.com&quot;)));

	/* It is recommended to use the default priorities */
	CHECK(gnutls_set_default_priority(session));

	/* put the x509 credentials to the current session
	 */
	CHECK(gnutls_credentials_set(session, GNUTLS_CRD_CERTIFICATE, xcred));
	gnutls_session_set_verify_cert(session, &quot;www.example.com&quot;, 0);

	/* connect to the peer
	 */
	sd = tcp_connect();

	gnutls_transport_set_int(session, sd);
	gnutls_handshake_set_timeout(session, GNUTLS_DEFAULT_HANDSHAKE_TIMEOUT);

	/* Perform the TLS handshake
	 */
	do {
		ret = gnutls_handshake(session);
	} while (ret &lt; 0 &amp;&amp; gnutls_error_is_fatal(ret) == 0);
	if (ret &lt; 0) {
		if (ret == GNUTLS_E_CERTIFICATE_VERIFICATION_ERROR) {
			/* check certificate verification status */
			type = gnutls_certificate_type_get(session);
			status = gnutls_session_get_verify_cert_status(session);
			CHECK(gnutls_certificate_verification_status_print(
				status, type, &amp;out, 0));
			printf(&quot;cert verify output: %s\n&quot;, out.data);
			gnutls_free(out.data);
		}
		fprintf(stderr, &quot;*** Handshake failed: %s\n&quot;,
			gnutls_strerror(ret));
		goto end;
	} else {
		desc = gnutls_session_get_desc(session);
		printf(&quot;- Session info: %s\n&quot;, desc);
		gnutls_free(desc);
	}

	/* send data */
	LOOP_CHECK(ret, gnutls_record_send(session, MSG, strlen(MSG)));

	LOOP_CHECK(ret, gnutls_record_recv(session, buffer, MAX_BUF));
	if (ret == 0) {
		printf(&quot;- Peer has closed the TLS connection\n&quot;);
		goto end;
	} else if (ret &lt; 0 &amp;&amp; gnutls_error_is_fatal(ret) == 0) {
		fprintf(stderr, &quot;*** Warning: %s\n&quot;, gnutls_strerror(ret));
	} else if (ret &lt; 0) {
		fprintf(stderr, &quot;*** Error: %s\n&quot;, gnutls_strerror(ret));
		goto end;
	}

	if (ret &gt; 0) {
		printf(&quot;- Received %d bytes: &quot;, ret);
		for (ii = 0; ii &lt; ret; ii++) {
			fputc(buffer[ii], stdout);
		}
		fputs(&quot;\n&quot;, stdout);
	}

	CHECK(gnutls_bye(session, GNUTLS_SHUT_RDWR));

end:

	tcp_close(sd);

	gnutls_deinit(session);

	gnutls_certificate_free_credentials(xcred);

	gnutls_global_deinit();

	return 0;
}
</pre>

<hr>
</div>
<div class="subsection-level-extent" id="Datagram-TLS-client-example">
<div class="nav-panel">
<p>
Next: <a href="#Client-using-a-smart-card-with-TLS" accesskey="n" rel="next">Using a smart card with TLS</a>, Previous: <a href="#Client-example-with-X_002e509-certificate-support" accesskey="p" rel="prev">Client example with <abbr class="acronym">X.509</abbr> certificate support</a>, Up: <a href="#Client-examples" accesskey="u" rel="up">Client examples</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Datagram-TLS-client-example-1"><span>7.1.2 Datagram <abbr class="acronym">TLS</abbr> client example<a class="copiable-link" href="#Datagram-TLS-client-example-1"> &para;</a></span></h4>

<p>This is a client that uses <abbr class="acronym">UDP</abbr> to connect to a
server. This is the <abbr class="acronym">DTLS</abbr> equivalent to the TLS example
with X.509 certificates.
</p>
<pre class="verbatim">/* This example code is placed in the public domain. */

#ifdef HAVE_CONFIG_H
#include &lt;config.h&gt;
#endif

#include &lt;stdio.h&gt;
#include &lt;stdlib.h&gt;
#include &lt;string.h&gt;
#include &lt;sys/types.h&gt;
#include &lt;sys/socket.h&gt;
#include &lt;arpa/inet.h&gt;
#include &lt;assert.h&gt;
#include &lt;unistd.h&gt;
#include &lt;gnutls/gnutls.h&gt;
#include &lt;gnutls/dtls.h&gt;

/* A very basic Datagram TLS client, over UDP with X.509 authentication.
 */

#define CHECK(x) assert((x) &gt;= 0)
#define LOOP_CHECK(rval, cmd)                                             \
	do {                                                              \
		rval = cmd;                                               \
	} while (rval == GNUTLS_E_AGAIN || rval == GNUTLS_E_INTERRUPTED); \
	assert(rval &gt;= 0)

#define MAX_BUF 1024
#define MSG &quot;GET / HTTP/1.0\r\n\r\n&quot;

extern int udp_connect(void);
extern void udp_close(int sd);
extern int verify_certificate_callback(gnutls_session_t session);

int main(void)
{
	int ret, sd, ii;
	gnutls_session_t session;
	char buffer[MAX_BUF + 1];
	gnutls_certificate_credentials_t xcred;

	if (gnutls_check_version(&quot;3.1.4&quot;) == NULL) {
		fprintf(stderr,
			&quot;GnuTLS 3.1.4 or later is required for this example\n&quot;);
		exit(1);
	}

	/* for backwards compatibility with gnutls &lt; 3.3.0 */
	CHECK(gnutls_global_init());

	/* X509 stuff */
	CHECK(gnutls_certificate_allocate_credentials(&amp;xcred));

	/* sets the system trusted CAs for Internet PKI */
	CHECK(gnutls_certificate_set_x509_system_trust(xcred));

	/* Initialize TLS session */
	CHECK(gnutls_init(&amp;session, GNUTLS_CLIENT | GNUTLS_DATAGRAM));

	/* Use default priorities */
	CHECK(gnutls_set_default_priority(session));

	/* put the x509 credentials to the current session */
	CHECK(gnutls_credentials_set(session, GNUTLS_CRD_CERTIFICATE, xcred));
	CHECK(gnutls_server_name_set(session, GNUTLS_NAME_DNS,
				     &quot;www.example.com&quot;,
				     strlen(&quot;www.example.com&quot;)));

	gnutls_session_set_verify_cert(session, &quot;www.example.com&quot;, 0);

	/* connect to the peer */
	sd = udp_connect();

	gnutls_transport_set_int(session, sd);

	/* set the connection MTU */
	gnutls_dtls_set_mtu(session, 1000);
	/* gnutls_dtls_set_timeouts(session, 1000, 60000); */

	/* Perform the TLS handshake */
	do {
		ret = gnutls_handshake(session);
	} while (ret == GNUTLS_E_INTERRUPTED || ret == GNUTLS_E_AGAIN);
	/* Note that DTLS may also receive GNUTLS_E_LARGE_PACKET */

	if (ret &lt; 0) {
		fprintf(stderr, &quot;*** Handshake failed\n&quot;);
		gnutls_perror(ret);
		goto end;
	} else {
		char *desc;

		desc = gnutls_session_get_desc(session);
		printf(&quot;- Session info: %s\n&quot;, desc);
		gnutls_free(desc);
	}

	LOOP_CHECK(ret, gnutls_record_send(session, MSG, strlen(MSG)));

	LOOP_CHECK(ret, gnutls_record_recv(session, buffer, MAX_BUF));
	if (ret == 0) {
		printf(&quot;- Peer has closed the TLS connection\n&quot;);
		goto end;
	} else if (ret &lt; 0 &amp;&amp; gnutls_error_is_fatal(ret) == 0) {
		fprintf(stderr, &quot;*** Warning: %s\n&quot;, gnutls_strerror(ret));
	} else if (ret &lt; 0) {
		fprintf(stderr, &quot;*** Error: %s\n&quot;, gnutls_strerror(ret));
		goto end;
	}

	if (ret &gt; 0) {
		printf(&quot;- Received %d bytes: &quot;, ret);
		for (ii = 0; ii &lt; ret; ii++) {
			fputc(buffer[ii], stdout);
		}
		fputs(&quot;\n&quot;, stdout);
	}

	/* It is suggested not to use GNUTLS_SHUT_RDWR in DTLS
	 * connections because the peer's closure message might
	 * be lost */
	CHECK(gnutls_bye(session, GNUTLS_SHUT_WR));

end:

	udp_close(sd);

	gnutls_deinit(session);

	gnutls_certificate_free_credentials(xcred);

	gnutls_global_deinit();

	return 0;
}
</pre>

<hr>
</div>
<div class="subsection-level-extent" id="Client-using-a-smart-card-with-TLS">
<div class="nav-panel">
<p>
Next: <a href="#Client-with-Resume-capability-example" accesskey="n" rel="next">Client with resume capability example</a>, Previous: <a href="#Datagram-TLS-client-example" accesskey="p" rel="prev">Datagram <abbr class="acronym">TLS</abbr> client example</a>, Up: <a href="#Client-examples" accesskey="u" rel="up">Client examples</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Using-a-smart-card-with-TLS"><span>7.1.3 Using a smart card with TLS<a class="copiable-link" href="#Using-a-smart-card-with-TLS"> &para;</a></span></h4>
<a class="anchor" id="ex_002dpkcs11_002dclient"></a><a class="index-entry-id" id="index-Smart-card-example"></a>

<p>This example will demonstrate how to load keys and certificates
from a smart-card or any other <abbr class="acronym">PKCS</abbr> #11 token, and 
use it in a TLS connection. The difference between this and the
<a class="ref" href="#Client-example-with-X_002e509-certificate-support">Client example with <abbr class="acronym">X.509</abbr> certificate support</a> is that the
client keys are provided as PKCS #11 URIs instead of files.
</p>
<pre class="verbatim">/* This example code is placed in the public domain. */

#ifdef HAVE_CONFIG_H
#include &lt;config.h&gt;
#endif

#include &lt;stdio.h&gt;
#include &lt;stdlib.h&gt;
#include &lt;string.h&gt;
#include &lt;sys/types.h&gt;
#include &lt;sys/socket.h&gt;
#include &lt;arpa/inet.h&gt;
#include &lt;unistd.h&gt;
#include &lt;gnutls/gnutls.h&gt;
#include &lt;gnutls/x509.h&gt;
#include &lt;gnutls/pkcs11.h&gt;
#include &lt;assert.h&gt;
#include &lt;sys/types.h&gt;
#include &lt;sys/stat.h&gt;
#include &lt;fcntl.h&gt;
#include &lt;getpass.h&gt; /* for getpass() */

/* A TLS client that loads the certificate and key.
 */

#define CHECK(x) assert((x) &gt;= 0)

#define MAX_BUF 1024
#define MSG &quot;GET / HTTP/1.0\r\n\r\n&quot;
#define MIN(x, y) (((x) &lt; (y)) ? (x) : (y))

#define CAFILE &quot;/etc/ssl/certs/ca-certificates.crt&quot;

/* The URLs of the objects can be obtained
 * using p11tool --list-all --login
 */
#define KEY_URL                                                     \
	&quot;pkcs11:manufacturer=SomeManufacturer;object=Private%20Key&quot; \
	&quot;;objecttype=private;id=%db%5b%3e%b5%72%33&quot;
#define CERT_URL                                                   \
	&quot;pkcs11:manufacturer=SomeManufacturer;object=Certificate;&quot; \
	&quot;objecttype=cert;id=db%5b%3e%b5%72%33&quot;

extern int tcp_connect(void);
extern void tcp_close(int sd);

static int pin_callback(void *user, int attempt, const char *token_url,
			const char *token_label, unsigned int flags, char *pin,
			size_t pin_max)
{
	const char *password;
	int len;

	printf(&quot;PIN required for token '%s' with URL '%s'\n&quot;, token_label,
	       token_url);
	if (flags &amp; GNUTLS_PIN_FINAL_TRY)
		printf(&quot;*** This is the final try before locking!\n&quot;);
	if (flags &amp; GNUTLS_PIN_COUNT_LOW)
		printf(&quot;*** Only few tries left before locking!\n&quot;);
	if (flags &amp; GNUTLS_PIN_WRONG)
		printf(&quot;*** Wrong PIN\n&quot;);

	password = getpass(&quot;Enter pin: &quot;);
	/* FIXME: ensure that we are in UTF-8 locale */
	if (password == NULL || password[0] == 0) {
		fprintf(stderr, &quot;No password given\n&quot;);
		exit(1);
	}

	len = MIN(pin_max - 1, strlen(password));
	memcpy(pin, password, len);
	pin[len] = 0;

	return 0;
}

int main(void)
{
	int ret, sd, ii;
	gnutls_session_t session;
	char buffer[MAX_BUF + 1];
	gnutls_certificate_credentials_t xcred;
	/* Allow connections to servers that have OpenPGP keys as well.
	 */

	if (gnutls_check_version(&quot;3.1.4&quot;) == NULL) {
		fprintf(stderr,
			&quot;GnuTLS 3.1.4 or later is required for this example\n&quot;);
		exit(1);
	}

	/* for backwards compatibility with gnutls &lt; 3.3.0 */
	CHECK(gnutls_global_init());

	/* The PKCS11 private key operations may require PIN.
	 * Register a callback. */
	gnutls_pkcs11_set_pin_function(pin_callback, NULL);

	/* X509 stuff */
	CHECK(gnutls_certificate_allocate_credentials(&amp;xcred));

	/* sets the trusted cas file
	 */
	CHECK(gnutls_certificate_set_x509_trust_file(xcred, CAFILE,
						     GNUTLS_X509_FMT_PEM));

	CHECK(gnutls_certificate_set_x509_key_file(xcred, CERT_URL, KEY_URL,
						   GNUTLS_X509_FMT_DER));

	/* Note that there is no server certificate verification in this example
	 */

	/* Initialize TLS session
	 */
	CHECK(gnutls_init(&amp;session, GNUTLS_CLIENT));

	/* Use default priorities */
	CHECK(gnutls_set_default_priority(session));

	/* put the x509 credentials to the current session
	 */
	CHECK(gnutls_credentials_set(session, GNUTLS_CRD_CERTIFICATE, xcred));

	/* connect to the peer
	 */
	sd = tcp_connect();

	gnutls_transport_set_int(session, sd);

	/* Perform the TLS handshake
	 */
	ret = gnutls_handshake(session);

	if (ret &lt; 0) {
		fprintf(stderr, &quot;*** Handshake failed\n&quot;);
		gnutls_perror(ret);
		goto end;
	} else {
		char *desc;

		desc = gnutls_session_get_desc(session);
		printf(&quot;- Session info: %s\n&quot;, desc);
		gnutls_free(desc);
	}

	CHECK(gnutls_record_send(session, MSG, strlen(MSG)));

	ret = gnutls_record_recv(session, buffer, MAX_BUF);
	if (ret == 0) {
		printf(&quot;- Peer has closed the TLS connection\n&quot;);
		goto end;
	} else if (ret &lt; 0) {
		fprintf(stderr, &quot;*** Error: %s\n&quot;, gnutls_strerror(ret));
		goto end;
	}

	printf(&quot;- Received %d bytes: &quot;, ret);
	for (ii = 0; ii &lt; ret; ii++) {
		fputc(buffer[ii], stdout);
	}
	fputs(&quot;\n&quot;, stdout);

	CHECK(gnutls_bye(session, GNUTLS_SHUT_RDWR));

end:

	tcp_close(sd);

	gnutls_deinit(session);

	gnutls_certificate_free_credentials(xcred);

	gnutls_global_deinit();

	return 0;
}
</pre>

<hr>
</div>
<div class="subsection-level-extent" id="Client-with-Resume-capability-example">
<div class="nav-panel">
<p>
Next: <a href="#Client-example-with-SSH_002dstyle-certificate-verification" accesskey="n" rel="next">Client example with SSH-style certificate verification</a>, Previous: <a href="#Client-using-a-smart-card-with-TLS" accesskey="p" rel="prev">Using a smart card with TLS</a>, Up: <a href="#Client-examples" accesskey="u" rel="up">Client examples</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Client-with-resume-capability-example"><span>7.1.4 Client with resume capability example<a class="copiable-link" href="#Client-with-resume-capability-example"> &para;</a></span></h4>
<a class="anchor" id="ex_002dresume_002dclient"></a>
<p>This is a modification of the simple client example. Here we
demonstrate the use of session resumption. The client tries to connect
once using <abbr class="acronym">TLS</abbr>, close the connection and then try to
establish a new connection using the previously negotiated data.
</p>
<pre class="verbatim">/* This example code is placed in the public domain. */

#ifdef HAVE_CONFIG_H
#include &lt;config.h&gt;
#endif

#include &lt;string.h&gt;
#include &lt;stdio.h&gt;
#include &lt;stdlib.h&gt;
#include &lt;assert.h&gt;
#include &lt;gnutls/gnutls.h&gt;

extern void check_alert(gnutls_session_t session, int ret);
extern int tcp_connect(void);
extern void tcp_close(int sd);

/* A very basic TLS client, with X.509 authentication and server certificate
 * verification as well as session resumption.
 *
 * Note that error recovery is minimal for simplicity.
 */

#define CHECK(x) assert((x) &gt;= 0)
#define LOOP_CHECK(rval, cmd)                                             \
	do {                                                              \
		rval = cmd;                                               \
	} while (rval == GNUTLS_E_AGAIN || rval == GNUTLS_E_INTERRUPTED); \
	assert(rval &gt;= 0)

#define MAX_BUF 1024
#define MSG &quot;GET / HTTP/1.0\r\n\r\n&quot;

int main(void)
{
	int ret;
	int sd, ii;
	gnutls_session_t session;
	char buffer[MAX_BUF + 1];
	gnutls_certificate_credentials_t xcred;

	/* variables used in session resuming 
	 */
	int t;
	gnutls_datum_t sdata;

	/* for backwards compatibility with gnutls &lt; 3.3.0 */
	CHECK(gnutls_global_init());

	CHECK(gnutls_certificate_allocate_credentials(&amp;xcred));
	CHECK(gnutls_certificate_set_x509_system_trust(xcred));

	for (t = 0; t &lt; 2; t++) { /* connect 2 times to the server */

		sd = tcp_connect();

		CHECK(gnutls_init(&amp;session, GNUTLS_CLIENT));

		CHECK(gnutls_server_name_set(session, GNUTLS_NAME_DNS,
					     &quot;www.example.com&quot;,
					     strlen(&quot;www.example.com&quot;)));
		gnutls_session_set_verify_cert(session, &quot;www.example.com&quot;, 0);

		CHECK(gnutls_set_default_priority(session));

		gnutls_transport_set_int(session, sd);
		gnutls_handshake_set_timeout(session,
					     GNUTLS_DEFAULT_HANDSHAKE_TIMEOUT);

		gnutls_credentials_set(session, GNUTLS_CRD_CERTIFICATE, xcred);

		if (t &gt; 0) {
			/* if this is not the first time we connect */
			CHECK(gnutls_session_set_data(session, sdata.data,
						      sdata.size));
			gnutls_free(sdata.data);
		}

		/* Perform the TLS handshake
		 */
		do {
			ret = gnutls_handshake(session);
		} while (ret &lt; 0 &amp;&amp; gnutls_error_is_fatal(ret) == 0);

		if (ret &lt; 0) {
			fprintf(stderr, &quot;*** Handshake failed\n&quot;);
			gnutls_perror(ret);
			goto end;
		} else {
			printf(&quot;- Handshake was completed\n&quot;);
		}

		if (t == 0) { /* the first time we connect */
			/* get the session data */
			CHECK(gnutls_session_get_data2(session, &amp;sdata));
		} else { /* the second time we connect */

			/* check if we actually resumed the previous session */
			if (gnutls_session_is_resumed(session) != 0) {
				printf(&quot;- Previous session was resumed\n&quot;);
			} else {
				fprintf(stderr,
					&quot;*** Previous session was NOT resumed\n&quot;);
			}
		}

		LOOP_CHECK(ret, gnutls_record_send(session, MSG, strlen(MSG)));

		LOOP_CHECK(ret, gnutls_record_recv(session, buffer, MAX_BUF));
		if (ret == 0) {
			printf(&quot;- Peer has closed the TLS connection\n&quot;);
			goto end;
		} else if (ret &lt; 0 &amp;&amp; gnutls_error_is_fatal(ret) == 0) {
			fprintf(stderr, &quot;*** Warning: %s\n&quot;,
				gnutls_strerror(ret));
		} else if (ret &lt; 0) {
			fprintf(stderr, &quot;*** Error: %s\n&quot;,
				gnutls_strerror(ret));
			goto end;
		}

		if (ret &gt; 0) {
			printf(&quot;- Received %d bytes: &quot;, ret);
			for (ii = 0; ii &lt; ret; ii++) {
				fputc(buffer[ii], stdout);
			}
			fputs(&quot;\n&quot;, stdout);
		}

		gnutls_bye(session, GNUTLS_SHUT_RDWR);

	end:

		tcp_close(sd);

		gnutls_deinit(session);

	} /* for() */

	gnutls_certificate_free_credentials(xcred);

	gnutls_global_deinit();

	return 0;
}
</pre>



<hr>
</div>
<div class="subsection-level-extent" id="Client-example-with-SSH_002dstyle-certificate-verification">
<div class="nav-panel">
<p>
Previous: <a href="#Client-with-Resume-capability-example" accesskey="p" rel="prev">Client with resume capability example</a>, Up: <a href="#Client-examples" accesskey="u" rel="up">Client examples</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Client-example-with-SSH_002dstyle-certificate-verification-1"><span>7.1.5 Client example with SSH-style certificate verification<a class="copiable-link" href="#Client-example-with-SSH_002dstyle-certificate-verification-1"> &para;</a></span></h4>

<p>This is an alternative verification function that will use the
X.509 certificate authorities for verification, but also assume an
trust on first use (SSH-like) authentication system. That is the user is 
prompted on unknown public keys and known public keys are considered 
trusted.
</p>
<pre class="verbatim">/* This example code is placed in the public domain. */

#ifdef HAVE_CONFIG_H
#include &lt;config.h&gt;
#endif

#include &lt;stdio.h&gt;
#include &lt;stdlib.h&gt;
#include &lt;string.h&gt;
#include &lt;gnutls/gnutls.h&gt;
#include &lt;gnutls/x509.h&gt;
#include &lt;assert.h&gt;
#include &quot;examples.h&quot;

#define CHECK(x) assert((x) &gt;= 0)

/* This function will verify the peer's certificate, check
 * if the hostname matches. In addition it will perform an
 * SSH-style authentication, where ultimately trusted keys
 * are only the keys that have been seen before.
 */
int _ssh_verify_certificate_callback(gnutls_session_t session)
{
	unsigned int status;
	const gnutls_datum_t *cert_list;
	unsigned int cert_list_size;
	int ret, type;
	gnutls_datum_t out;
	const char *hostname;

	/* read hostname */
	hostname = gnutls_session_get_ptr(session);

	/* This verification function uses the trusted CAs in the credentials
	 * structure. So you must have installed one or more CA certificates.
	 */
	CHECK(gnutls_certificate_verify_peers3(session, hostname, &amp;status));

	type = gnutls_certificate_type_get(session);

	CHECK(gnutls_certificate_verification_status_print(status, type, &amp;out,
							   0));
	printf(&quot;%s&quot;, out.data);

	gnutls_free(out.data);

	if (status != 0) /* Certificate is not trusted */
		return GNUTLS_E_CERTIFICATE_ERROR;

	/* Do SSH verification */
	cert_list = gnutls_certificate_get_peers(session, &amp;cert_list_size);
	if (cert_list == NULL) {
		printf(&quot;No certificate was found!\n&quot;);
		return GNUTLS_E_CERTIFICATE_ERROR;
	}

	/* service may be obtained alternatively using getservbyport() */
	ret = gnutls_verify_stored_pubkey(NULL, NULL, hostname, &quot;https&quot;, type,
					  &amp;cert_list[0], 0);
	if (ret == GNUTLS_E_NO_CERTIFICATE_FOUND) {
		printf(&quot;Host %s is not known.&quot;, hostname);
		if (status == 0)
			printf(&quot;Its certificate is valid for %s.\n&quot;, hostname);

		/* the certificate must be printed and user must be asked on
		 * whether it is trustworthy. --see gnutls_x509_crt_print() */

		/* if not trusted */
		return GNUTLS_E_CERTIFICATE_ERROR;
	} else if (ret == GNUTLS_E_CERTIFICATE_KEY_MISMATCH) {
		printf(&quot;Warning: host %s is known but has another key associated.&quot;,
		       hostname);
		printf(&quot;It might be that the server has multiple keys, or you are under attack\n&quot;);
		if (status == 0)
			printf(&quot;Its certificate is valid for %s.\n&quot;, hostname);

		/* the certificate must be printed and user must be asked on
		 * whether it is trustworthy. --see gnutls_x509_crt_print() */

		/* if not trusted */
		return GNUTLS_E_CERTIFICATE_ERROR;
	} else if (ret &lt; 0) {
		printf(&quot;gnutls_verify_stored_pubkey: %s\n&quot;,
		       gnutls_strerror(ret));
		return ret;
	}

	/* user trusts the key -&gt; store it */
	if (ret != 0) {
		CHECK(gnutls_store_pubkey(NULL, NULL, hostname, &quot;https&quot;, type,
					  &amp;cert_list[0], 0, 0));
	}

	/* notify gnutls to continue handshake normally */
	return 0;
}
</pre>
<hr>
</div>
</div>
<div class="section-level-extent" id="Server-examples">
<div class="nav-panel">
<p>
Next: <a href="#More-advanced-client-and-servers" accesskey="n" rel="next">More advanced client and servers</a>, Previous: <a href="#Client-examples" accesskey="p" rel="prev">Client examples</a>, Up: <a href="#GnuTLS-application-examples" accesskey="u" rel="up">GnuTLS application examples</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Server-examples-1"><span>7.2 Server examples<a class="copiable-link" href="#Server-examples-1"> &para;</a></span></h3>

<p>This section contains examples of <abbr class="acronym">TLS</abbr> and <abbr class="acronym">SSL</abbr>
servers, using <abbr class="acronym">GnuTLS</abbr>.
</p>

<ul class="mini-toc">
<li><a href="#Echo-server-with-X_002e509-authentication" accesskey="1">Echo server with <abbr class="acronym">X.509</abbr> authentication</a></li>
<li><a href="#DTLS-echo-server-with-X_002e509-authentication" accesskey="2">DTLS echo server with <abbr class="acronym">X.509</abbr> authentication</a></li>
</ul>
<hr>
<div class="subsection-level-extent" id="Echo-server-with-X_002e509-authentication">
<div class="nav-panel">
<p>
Next: <a href="#DTLS-echo-server-with-X_002e509-authentication" accesskey="n" rel="next">DTLS echo server with <abbr class="acronym">X.509</abbr> authentication</a>, Up: <a href="#Server-examples" accesskey="u" rel="up">Server examples</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Echo-server-with-X_002e509-authentication-1"><span>7.2.1 Echo server with <abbr class="acronym">X.509</abbr> authentication<a class="copiable-link" href="#Echo-server-with-X_002e509-authentication-1"> &para;</a></span></h4>

<p>This example is a very simple echo server which supports
<abbr class="acronym">X.509</abbr> authentication.
</p>
<pre class="verbatim">/* This example code is placed in the public domain. */

#ifdef HAVE_CONFIG_H
#include &lt;config.h&gt;
#endif

#include &lt;stdio.h&gt;
#include &lt;stdlib.h&gt;
#include &lt;errno.h&gt;
#include &lt;sys/types.h&gt;
#include &lt;sys/socket.h&gt;
#include &lt;arpa/inet.h&gt;
#include &lt;netinet/in.h&gt;
#include &lt;string.h&gt;
#include &lt;unistd.h&gt;
#include &lt;gnutls/gnutls.h&gt;
#include &lt;assert.h&gt;

#define KEYFILE &quot;key.pem&quot;
#define CERTFILE &quot;cert.pem&quot;
#define CAFILE &quot;/etc/ssl/certs/ca-certificates.crt&quot;
#define CRLFILE &quot;crl.pem&quot;

#define CHECK(x) assert((x) &gt;= 0)
#define LOOP_CHECK(rval, cmd) \
	do {                  \
		rval = cmd;   \
	} while (rval == GNUTLS_E_AGAIN || rval == GNUTLS_E_INTERRUPTED)

/* The OCSP status file contains up to date information about revocation
 * of the server's certificate. That can be periodically be updated
 * using:
 * $ ocsptool --ask --load-cert your_cert.pem --load-issuer your_issuer.pem
 *            --load-signer your_issuer.pem --outfile ocsp-status.der
 */
#define OCSP_STATUS_FILE &quot;ocsp-status.der&quot;

/* This is a sample TLS 1.0 echo server, using X.509 authentication and
 * OCSP stapling support.
 */

#define MAX_BUF 1024
#define PORT 5556 /* listen to 5556 port */

int main(void)
{
	int listen_sd;
	int sd, ret;
	gnutls_certificate_credentials_t x509_cred;
	gnutls_priority_t priority_cache;
	struct sockaddr_in sa_serv;
	struct sockaddr_in sa_cli;
	socklen_t client_len;
	char topbuf[512];
	gnutls_session_t session;
	char buffer[MAX_BUF + 1];
	int optval = 1;

	/* for backwards compatibility with gnutls &lt; 3.3.0 */
	CHECK(gnutls_global_init());

	CHECK(gnutls_certificate_allocate_credentials(&amp;x509_cred));

	CHECK(gnutls_certificate_set_x509_trust_file(x509_cred, CAFILE,
						     GNUTLS_X509_FMT_PEM));

	CHECK(gnutls_certificate_set_x509_crl_file(x509_cred, CRLFILE,
						   GNUTLS_X509_FMT_PEM));

	/* The following code sets the certificate key pair as well as, 
	 * an OCSP response which corresponds to it. It is possible
	 * to set multiple key-pairs and multiple OCSP status responses
	 * (the latter since 3.5.6). See the manual pages of the individual
	 * functions for more information.
	 */
	CHECK(gnutls_certificate_set_x509_key_file(x509_cred, CERTFILE, KEYFILE,
						   GNUTLS_X509_FMT_PEM));

	CHECK(gnutls_certificate_set_ocsp_status_request_file(
		x509_cred, OCSP_STATUS_FILE, 0));

	CHECK(gnutls_priority_init(&amp;priority_cache, NULL, NULL));

	/* Instead of the default options as shown above one could specify
	 * additional options such as server precedence in ciphersuite selection
	 * as follows:
	 * gnutls_priority_init2(&amp;priority_cache,
	 *                       &quot;%SERVER_PRECEDENCE&quot;,
	 *                       NULL, GNUTLS_PRIORITY_INIT_DEF_APPEND);
	 */

#if GNUTLS_VERSION_NUMBER &gt;= 0x030506
	/* only available since GnuTLS 3.5.6, on previous versions see
	 * gnutls_certificate_set_dh_params(). */
	gnutls_certificate_set_known_dh_params(x509_cred,
					       GNUTLS_SEC_PARAM_MEDIUM);
#endif

	/* Socket operations
	 */
	listen_sd = socket(AF_INET, SOCK_STREAM, 0);

	memset(&amp;sa_serv, '\0', sizeof(sa_serv));
	sa_serv.sin_family = AF_INET;
	sa_serv.sin_addr.s_addr = INADDR_ANY;
	sa_serv.sin_port = htons(PORT); /* Server Port number */

	setsockopt(listen_sd, SOL_SOCKET, SO_REUSEADDR, (void *)&amp;optval,
		   sizeof(int));

	bind(listen_sd, (struct sockaddr *)&amp;sa_serv, sizeof(sa_serv));

	listen(listen_sd, 1024);

	printf(&quot;Server ready. Listening to port '%d'.\n\n&quot;, PORT);

	client_len = sizeof(sa_cli);
	for (;;) {
		CHECK(gnutls_init(&amp;session, GNUTLS_SERVER));
		CHECK(gnutls_priority_set(session, priority_cache));
		CHECK(gnutls_credentials_set(session, GNUTLS_CRD_CERTIFICATE,
					     x509_cred));

		/* We don't request any certificate from the client.
		 * If we did we would need to verify it. One way of
		 * doing that is shown in the &quot;Verifying a certificate&quot;
		 * example.
		 */
		gnutls_certificate_server_set_request(session,
						      GNUTLS_CERT_IGNORE);
		gnutls_handshake_set_timeout(session,
					     GNUTLS_DEFAULT_HANDSHAKE_TIMEOUT);

		sd = accept(listen_sd, (struct sockaddr *)&amp;sa_cli, &amp;client_len);

		printf(&quot;- connection from %s, port %d\n&quot;,
		       inet_ntop(AF_INET, &amp;sa_cli.sin_addr, topbuf,
				 sizeof(topbuf)),
		       ntohs(sa_cli.sin_port));

		gnutls_transport_set_int(session, sd);

		LOOP_CHECK(ret, gnutls_handshake(session));
		if (ret &lt; 0) {
			close(sd);
			gnutls_deinit(session);
			fprintf(stderr, &quot;*** Handshake has failed (%s)\n\n&quot;,
				gnutls_strerror(ret));
			continue;
		}
		printf(&quot;- Handshake was completed\n&quot;);

		/* see the Getting peer's information example */
		/* print_info(session); */

		for (;;) {
			LOOP_CHECK(ret, gnutls_record_recv(session, buffer,
							   MAX_BUF));

			if (ret == 0) {
				printf(&quot;\n- Peer has closed the GnuTLS connection\n&quot;);
				break;
			} else if (ret &lt; 0 &amp;&amp; gnutls_error_is_fatal(ret) == 0) {
				fprintf(stderr, &quot;*** Warning: %s\n&quot;,
					gnutls_strerror(ret));
			} else if (ret &lt; 0) {
				fprintf(stderr,
					&quot;\n*** Received corrupted &quot;
					&quot;data(%d). Closing the connection.\n\n&quot;,
					ret);
				break;
			} else if (ret &gt; 0) {
				/* echo data back to the client
				 */
				CHECK(gnutls_record_send(session, buffer, ret));
			}
		}
		printf(&quot;\n&quot;);
		/* do not wait for the peer to close the connection.
		 */
		LOOP_CHECK(ret, gnutls_bye(session, GNUTLS_SHUT_WR));

		close(sd);
		gnutls_deinit(session);
	}
	close(listen_sd);

	gnutls_certificate_free_credentials(x509_cred);
	gnutls_priority_deinit(priority_cache);

	gnutls_global_deinit();

	return 0;
}
</pre>

<hr>
</div>
<div class="subsection-level-extent" id="DTLS-echo-server-with-X_002e509-authentication">
<div class="nav-panel">
<p>
Previous: <a href="#Echo-server-with-X_002e509-authentication" accesskey="p" rel="prev">Echo server with <abbr class="acronym">X.509</abbr> authentication</a>, Up: <a href="#Server-examples" accesskey="u" rel="up">Server examples</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="DTLS-echo-server-with-X_002e509-authentication-1"><span>7.2.2 DTLS echo server with <abbr class="acronym">X.509</abbr> authentication<a class="copiable-link" href="#DTLS-echo-server-with-X_002e509-authentication-1"> &para;</a></span></h4>

<p>This example is a very simple echo server using Datagram TLS and 
<abbr class="acronym">X.509</abbr> authentication.
</p>
<pre class="verbatim">/* This example code is placed in the public domain. */

#ifdef HAVE_CONFIG_H
#include &lt;config.h&gt;
#endif

#include &lt;stdio.h&gt;
#include &lt;stdlib.h&gt;
#include &lt;errno.h&gt;
#include &lt;sys/types.h&gt;
#include &lt;sys/socket.h&gt;
#include &lt;arpa/inet.h&gt;
#include &lt;netinet/in.h&gt;
#include &lt;sys/select.h&gt;
#include &lt;netdb.h&gt;
#include &lt;string.h&gt;
#include &lt;unistd.h&gt;
#include &lt;gnutls/gnutls.h&gt;
#include &lt;gnutls/dtls.h&gt;

#define KEYFILE &quot;key.pem&quot;
#define CERTFILE &quot;cert.pem&quot;
#define CAFILE &quot;/etc/ssl/certs/ca-certificates.crt&quot;
#define CRLFILE &quot;crl.pem&quot;

/* This is a sample DTLS echo server, using X.509 authentication.
 * Note that error checking is minimal to simplify the example.
 */

#define LOOP_CHECK(rval, cmd) \
	do {                  \
		rval = cmd;   \
	} while (rval == GNUTLS_E_AGAIN || rval == GNUTLS_E_INTERRUPTED)

#define MAX_BUFFER 1024
#define PORT 5557

typedef struct {
	gnutls_session_t session;
	int fd;
	struct sockaddr *cli_addr;
	socklen_t cli_addr_size;
} priv_data_st;

static int pull_timeout_func(gnutls_transport_ptr_t ptr, unsigned int ms);
static ssize_t push_func(gnutls_transport_ptr_t p, const void *data,
			 size_t size);
static ssize_t pull_func(gnutls_transport_ptr_t p, void *data, size_t size);
static const char *human_addr(const struct sockaddr *sa, socklen_t salen,
			      char *buf, size_t buflen);
static int wait_for_connection(int fd);

/* Use global credentials and parameters to simplify
 * the example. */
static gnutls_certificate_credentials_t x509_cred;
static gnutls_priority_t priority_cache;

int main(void)
{
	int listen_sd;
	int sock, ret;
	struct sockaddr_in sa_serv;
	struct sockaddr_in cli_addr;
	socklen_t cli_addr_size;
	gnutls_session_t session;
	char buffer[MAX_BUFFER];
	priv_data_st priv;
	gnutls_datum_t cookie_key;
	gnutls_dtls_prestate_st prestate;
	int mtu = 1400;
	unsigned char sequence[8];

	/* this must be called once in the program
	 */
	gnutls_global_init();

	gnutls_certificate_allocate_credentials(&amp;x509_cred);
	gnutls_certificate_set_x509_trust_file(x509_cred, CAFILE,
					       GNUTLS_X509_FMT_PEM);

	gnutls_certificate_set_x509_crl_file(x509_cred, CRLFILE,
					     GNUTLS_X509_FMT_PEM);

	ret = gnutls_certificate_set_x509_key_file(x509_cred, CERTFILE, KEYFILE,
						   GNUTLS_X509_FMT_PEM);
	if (ret &lt; 0) {
		printf(&quot;No certificate or key were found\n&quot;);
		exit(1);
	}

	gnutls_certificate_set_known_dh_params(x509_cred,
					       GNUTLS_SEC_PARAM_MEDIUM);

	/* pre-3.6.3 equivalent:
	 * gnutls_priority_init(&amp;priority_cache,
	 *                      &quot;NORMAL:-VERS-TLS-ALL:+VERS-DTLS1.0:%SERVER_PRECEDENCE&quot;,
	 *                      NULL);
	 */
	gnutls_priority_init2(&amp;priority_cache, &quot;%SERVER_PRECEDENCE&quot;, NULL,
			      GNUTLS_PRIORITY_INIT_DEF_APPEND);

	gnutls_key_generate(&amp;cookie_key, GNUTLS_COOKIE_KEY_SIZE);

	/* Socket operations
	 */
	listen_sd = socket(AF_INET, SOCK_DGRAM, 0);

	memset(&amp;sa_serv, '\0', sizeof(sa_serv));
	sa_serv.sin_family = AF_INET;
	sa_serv.sin_addr.s_addr = INADDR_ANY;
	sa_serv.sin_port = htons(PORT);

	{ /* DTLS requires the IP don't fragment (DF) bit to be set */
#if defined(IP_DONTFRAG)
		int optval = 1;
		setsockopt(listen_sd, IPPROTO_IP, IP_DONTFRAG,
			   (const void *)&amp;optval, sizeof(optval));
#elif defined(IP_MTU_DISCOVER)
		int optval = IP_PMTUDISC_DO;
		setsockopt(listen_sd, IPPROTO_IP, IP_MTU_DISCOVER,
			   (const void *)&amp;optval, sizeof(optval));
#endif
	}

	bind(listen_sd, (struct sockaddr *)&amp;sa_serv, sizeof(sa_serv));

	printf(&quot;UDP server ready. Listening to port '%d'.\n\n&quot;, PORT);

	for (;;) {
		printf(&quot;Waiting for connection...\n&quot;);
		sock = wait_for_connection(listen_sd);
		if (sock &lt; 0)
			continue;

		cli_addr_size = sizeof(cli_addr);
		ret = recvfrom(sock, buffer, sizeof(buffer), MSG_PEEK,
			       (struct sockaddr *)&amp;cli_addr, &amp;cli_addr_size);
		if (ret &gt; 0) {
			memset(&amp;prestate, 0, sizeof(prestate));
			ret = gnutls_dtls_cookie_verify(&amp;cookie_key, &amp;cli_addr,
							sizeof(cli_addr),
							buffer, ret, &amp;prestate);
			if (ret &lt; 0) { /* cookie not valid */
				priv_data_st s;

				memset(&amp;s, 0, sizeof(s));
				s.fd = sock;
				s.cli_addr = (void *)&amp;cli_addr;
				s.cli_addr_size = sizeof(cli_addr);

				printf(&quot;Sending hello verify request to %s\n&quot;,
				       human_addr((struct sockaddr *)&amp;cli_addr,
						  sizeof(cli_addr), buffer,
						  sizeof(buffer)));

				gnutls_dtls_cookie_send(
					&amp;cookie_key, &amp;cli_addr,
					sizeof(cli_addr), &amp;prestate,
					(gnutls_transport_ptr_t)&amp;s, push_func);

				/* discard peeked data */
				recvfrom(sock, buffer, sizeof(buffer), 0,
					 (struct sockaddr *)&amp;cli_addr,
					 &amp;cli_addr_size);
				usleep(100);
				continue;
			}
			printf(&quot;Accepted connection from %s\n&quot;,
			       human_addr((struct sockaddr *)&amp;cli_addr,
					  sizeof(cli_addr), buffer,
					  sizeof(buffer)));
		} else
			continue;

		gnutls_init(&amp;session, GNUTLS_SERVER | GNUTLS_DATAGRAM);
		gnutls_priority_set(session, priority_cache);
		gnutls_credentials_set(session, GNUTLS_CRD_CERTIFICATE,
				       x509_cred);

		gnutls_dtls_prestate_set(session, &amp;prestate);
		gnutls_dtls_set_mtu(session, mtu);

		priv.session = session;
		priv.fd = sock;
		priv.cli_addr = (struct sockaddr *)&amp;cli_addr;
		priv.cli_addr_size = sizeof(cli_addr);

		gnutls_transport_set_ptr(session, &amp;priv);
		gnutls_transport_set_push_function(session, push_func);
		gnutls_transport_set_pull_function(session, pull_func);
		gnutls_transport_set_pull_timeout_function(session,
							   pull_timeout_func);

		LOOP_CHECK(ret, gnutls_handshake(session));
		/* Note that DTLS may also receive GNUTLS_E_LARGE_PACKET.
		 * In that case the MTU should be adjusted.
		 */

		if (ret &lt; 0) {
			fprintf(stderr, &quot;Error in handshake(): %s\n&quot;,
				gnutls_strerror(ret));
			gnutls_deinit(session);
			continue;
		}

		printf(&quot;- Handshake was completed\n&quot;);

		for (;;) {
			LOOP_CHECK(ret, gnutls_record_recv_seq(session, buffer,
							       MAX_BUFFER,
							       sequence));

			if (ret &lt; 0 &amp;&amp; gnutls_error_is_fatal(ret) == 0) {
				fprintf(stderr, &quot;*** Warning: %s\n&quot;,
					gnutls_strerror(ret));
				continue;
			} else if (ret &lt; 0) {
				fprintf(stderr, &quot;Error in recv(): %s\n&quot;,
					gnutls_strerror(ret));
				break;
			}

			if (ret == 0) {
				printf(&quot;EOF\n\n&quot;);
				break;
			}

			buffer[ret] = 0;
			printf(&quot;received[%.2x%.2x%.2x%.2x%.2x%.2x%.2x%.2x]: %s\n&quot;,
			       sequence[0], sequence[1], sequence[2],
			       sequence[3], sequence[4], sequence[5],
			       sequence[6], sequence[7], buffer);

			/* reply back */
			LOOP_CHECK(ret,
				   gnutls_record_send(session, buffer, ret));
			if (ret &lt; 0) {
				fprintf(stderr, &quot;Error in send(): %s\n&quot;,
					gnutls_strerror(ret));
				break;
			}
		}

		LOOP_CHECK(ret, gnutls_bye(session, GNUTLS_SHUT_WR));
		gnutls_deinit(session);
	}
	close(listen_sd);

	gnutls_certificate_free_credentials(x509_cred);
	gnutls_priority_deinit(priority_cache);

	gnutls_global_deinit();

	return 0;
}

static int wait_for_connection(int fd)
{
	fd_set rd, wr;
	int n;

	FD_ZERO(&amp;rd);
	FD_ZERO(&amp;wr);

	FD_SET(fd, &amp;rd);

	/* waiting part */
	n = select(fd + 1, &amp;rd, &amp;wr, NULL, NULL);
	if (n == -1 &amp;&amp; errno == EINTR)
		return -1;
	if (n &lt; 0) {
		perror(&quot;select()&quot;);
		exit(1);
	}

	return fd;
}

/* Wait for data to be received within a timeout period in milliseconds
 */
static int pull_timeout_func(gnutls_transport_ptr_t ptr, unsigned int ms)
{
	fd_set rfds;
	struct timeval tv;
	priv_data_st *priv = ptr;
	struct sockaddr_in cli_addr;
	socklen_t cli_addr_size;
	int ret;
	char c;

	FD_ZERO(&amp;rfds);
	FD_SET(priv-&gt;fd, &amp;rfds);

	tv.tv_sec = ms / 1000;
	tv.tv_usec = (ms % 1000) * 1000;

	ret = select(priv-&gt;fd + 1, &amp;rfds, NULL, NULL, &amp;tv);

	if (ret &lt;= 0)
		return ret;

	/* only report ok if the next message is from the peer we expect
	 * from 
	 */
	cli_addr_size = sizeof(cli_addr);
	ret = recvfrom(priv-&gt;fd, &amp;c, 1, MSG_PEEK, (struct sockaddr *)&amp;cli_addr,
		       &amp;cli_addr_size);
	if (ret &gt; 0) {
		if (cli_addr_size == priv-&gt;cli_addr_size &amp;&amp;
		    memcmp(&amp;cli_addr, priv-&gt;cli_addr, sizeof(cli_addr)) == 0)
			return 1;
	}

	return 0;
}

static ssize_t push_func(gnutls_transport_ptr_t p, const void *data,
			 size_t size)
{
	priv_data_st *priv = p;

	return sendto(priv-&gt;fd, data, size, 0, priv-&gt;cli_addr,
		      priv-&gt;cli_addr_size);
}

static ssize_t pull_func(gnutls_transport_ptr_t p, void *data, size_t size)
{
	priv_data_st *priv = p;
	struct sockaddr_in cli_addr;
	socklen_t cli_addr_size;
	char buffer[64];
	int ret;

	cli_addr_size = sizeof(cli_addr);
	ret = recvfrom(priv-&gt;fd, data, size, 0, (struct sockaddr *)&amp;cli_addr,
		       &amp;cli_addr_size);
	if (ret == -1)
		return ret;

	if (cli_addr_size == priv-&gt;cli_addr_size &amp;&amp;
	    memcmp(&amp;cli_addr, priv-&gt;cli_addr, sizeof(cli_addr)) == 0)
		return ret;

	printf(&quot;Denied connection from %s\n&quot;,
	       human_addr((struct sockaddr *)&amp;cli_addr, sizeof(cli_addr),
			  buffer, sizeof(buffer)));

	gnutls_transport_set_errno(priv-&gt;session, EAGAIN);
	return -1;
}

static const char *human_addr(const struct sockaddr *sa, socklen_t salen,
			      char *buf, size_t buflen)
{
	const char *save_buf = buf;
	size_t l;

	if (!buf || !buflen)
		return NULL;

	*buf = '\0';

	switch (sa-&gt;sa_family) {
#if HAVE_IPV6
	case AF_INET6:
		snprintf(buf, buflen, &quot;IPv6 &quot;);
		break;
#endif

	case AF_INET:
		snprintf(buf, buflen, &quot;IPv4 &quot;);
		break;
	}

	l = strlen(buf);
	buf += l;
	buflen -= l;

	if (getnameinfo(sa, salen, buf, buflen, NULL, 0, NI_NUMERICHOST) != 0)
		return NULL;

	l = strlen(buf);
	buf += l;
	buflen -= l;

	strncat(buf, &quot; port &quot;, buflen);

	l = strlen(buf);
	buf += l;
	buflen -= l;

	if (getnameinfo(sa, salen, NULL, 0, buf, buflen, NI_NUMERICSERV) != 0)
		return NULL;

	return save_buf;
}
</pre>



<hr>
</div>
</div>
<div class="section-level-extent" id="More-advanced-client-and-servers">
<div class="nav-panel">
<p>
Next: <a href="#OCSP-example" accesskey="n" rel="next">OCSP example</a>, Previous: <a href="#Server-examples" accesskey="p" rel="prev">Server examples</a>, Up: <a href="#GnuTLS-application-examples" accesskey="u" rel="up">GnuTLS application examples</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="More-advanced-client-and-servers-1"><span>7.3 More advanced client and servers<a class="copiable-link" href="#More-advanced-client-and-servers-1"> &para;</a></span></h3>

<p>This section has various, more advanced topics in client and servers.
</p>

<ul class="mini-toc">
<li><a href="#Client-example-with-anonymous-authentication" accesskey="1">Client example with anonymous authentication</a></li>
<li><a href="#Using-a-callback-to-select-the-certificate-to-use" accesskey="2">Using a callback to select the certificate to use</a></li>
<li><a href="#Obtaining-session-information" accesskey="3">Obtaining session information</a></li>
<li><a href="#Advanced-certificate-verification-example" accesskey="4">Advanced certificate verification</a></li>
<li><a href="#Client-example-with-PSK-authentication" accesskey="5">Client example with <abbr class="acronym">PSK</abbr> authentication</a></li>
<li><a href="#Client-example-with-SRP-authentication" accesskey="6">Client example with <abbr class="acronym">SRP</abbr> authentication</a></li>
<li><a href="#Legacy-client-example-with-X_002e509-certificate-support" accesskey="7">Legacy client example with <abbr class="acronym">X.509</abbr> certificate support</a></li>
<li><a href="#Client-example-in-C_002b_002b" accesskey="8">Client example using the C++ API</a></li>
<li><a href="#Echo-server-with-PSK-authentication" accesskey="9">Echo server with <abbr class="acronym">PSK</abbr> authentication</a></li>
<li><a href="#Echo-server-with-SRP-authentication">Echo server with <abbr class="acronym">SRP</abbr> authentication</a></li>
<li><a href="#Echo-server-with-anonymous-authentication">Echo server with anonymous authentication</a></li>
<li><a href="#Helper-functions-for-TCP-connections">Helper functions for TCP connections</a></li>
<li><a href="#Helper-functions-for-UDP-connections">Helper functions for UDP connections</a></li>
</ul>
<hr>
<div class="subsection-level-extent" id="Client-example-with-anonymous-authentication">
<div class="nav-panel">
<p>
Next: <a href="#Using-a-callback-to-select-the-certificate-to-use" accesskey="n" rel="next">Using a callback to select the certificate to use</a>, Up: <a href="#More-advanced-client-and-servers" accesskey="u" rel="up">More advanced client and servers</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Client-example-with-anonymous-authentication-1"><span>7.3.1 Client example with anonymous authentication<a class="copiable-link" href="#Client-example-with-anonymous-authentication-1"> &para;</a></span></h4>

<p>The simplest client using TLS is the one that doesn&rsquo;t do any
authentication.  This means no external certificates or passwords are
needed to set up the connection.  As could be expected, the connection
is vulnerable to man-in-the-middle (active or redirection) attacks.
However, the data are integrity protected and encrypted from
passive eavesdroppers.
</p>
<p>Note that due to the vulnerable nature of this method very few public
servers support it.
</p>
<pre class="verbatim">/* This example code is placed in the public domain. */

#ifdef HAVE_CONFIG_H
#include &lt;config.h&gt;
#endif

#include &lt;stdio.h&gt;
#include &lt;stdlib.h&gt;
#include &lt;string.h&gt;
#include &lt;sys/types.h&gt;
#include &lt;sys/socket.h&gt;
#include &lt;arpa/inet.h&gt;
#include &lt;unistd.h&gt;
#include &lt;assert.h&gt;
#include &lt;gnutls/gnutls.h&gt;

/* A very basic TLS client, with anonymous authentication.
 */

#define LOOP_CHECK(rval, cmd)                                             \
	do {                                                              \
		rval = cmd;                                               \
	} while (rval == GNUTLS_E_AGAIN || rval == GNUTLS_E_INTERRUPTED); \
	assert(rval &gt;= 0)

#define MAX_BUF 1024
#define MSG &quot;GET / HTTP/1.0\r\n\r\n&quot;

extern int tcp_connect(void);
extern void tcp_close(int sd);

int main(void)
{
	int ret, sd, ii;
	gnutls_session_t session;
	char buffer[MAX_BUF + 1];
	gnutls_anon_client_credentials_t anoncred;
	/* Need to enable anonymous KX specifically. */

	gnutls_global_init();

	gnutls_anon_allocate_client_credentials(&amp;anoncred);

	/* Initialize TLS session 
	 */
	gnutls_init(&amp;session, GNUTLS_CLIENT);

	/* Use default priorities */
	gnutls_priority_set_direct(session, &quot;PERFORMANCE:+ANON-ECDH:+ANON-DH&quot;,
				   NULL);

	/* put the anonymous credentials to the current session
	 */
	gnutls_credentials_set(session, GNUTLS_CRD_ANON, anoncred);

	/* connect to the peer
	 */
	sd = tcp_connect();

	gnutls_transport_set_int(session, sd);
	gnutls_handshake_set_timeout(session, GNUTLS_DEFAULT_HANDSHAKE_TIMEOUT);

	/* Perform the TLS handshake
	 */
	do {
		ret = gnutls_handshake(session);
	} while (ret &lt; 0 &amp;&amp; gnutls_error_is_fatal(ret) == 0);

	if (ret &lt; 0) {
		fprintf(stderr, &quot;*** Handshake failed\n&quot;);
		gnutls_perror(ret);
		goto end;
	} else {
		char *desc;

		desc = gnutls_session_get_desc(session);
		printf(&quot;- Session info: %s\n&quot;, desc);
		gnutls_free(desc);
	}

	LOOP_CHECK(ret, gnutls_record_send(session, MSG, strlen(MSG)));

	LOOP_CHECK(ret, gnutls_record_recv(session, buffer, MAX_BUF));
	if (ret == 0) {
		printf(&quot;- Peer has closed the TLS connection\n&quot;);
		goto end;
	} else if (ret &lt; 0 &amp;&amp; gnutls_error_is_fatal(ret) == 0) {
		fprintf(stderr, &quot;*** Warning: %s\n&quot;, gnutls_strerror(ret));
	} else if (ret &lt; 0) {
		fprintf(stderr, &quot;*** Error: %s\n&quot;, gnutls_strerror(ret));
		goto end;
	}

	if (ret &gt; 0) {
		printf(&quot;- Received %d bytes: &quot;, ret);
		for (ii = 0; ii &lt; ret; ii++) {
			fputc(buffer[ii], stdout);
		}
		fputs(&quot;\n&quot;, stdout);
	}

	LOOP_CHECK(ret, gnutls_bye(session, GNUTLS_SHUT_RDWR));

end:

	tcp_close(sd);

	gnutls_deinit(session);

	gnutls_anon_free_client_credentials(anoncred);

	gnutls_global_deinit();

	return 0;
}
</pre>
<hr>
</div>
<div class="subsection-level-extent" id="Using-a-callback-to-select-the-certificate-to-use">
<div class="nav-panel">
<p>
Next: <a href="#Obtaining-session-information" accesskey="n" rel="next">Obtaining session information</a>, Previous: <a href="#Client-example-with-anonymous-authentication" accesskey="p" rel="prev">Client example with anonymous authentication</a>, Up: <a href="#More-advanced-client-and-servers" accesskey="u" rel="up">More advanced client and servers</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Using-a-callback-to-select-the-certificate-to-use-1"><span>7.3.2 Using a callback to select the certificate to use<a class="copiable-link" href="#Using-a-callback-to-select-the-certificate-to-use-1"> &para;</a></span></h4>

<p>There are cases where a client holds several certificate and key
pairs, and may not want to load all of them in the credentials
structure.  The following example demonstrates the use of the
certificate selection callback.
</p>
<pre class="verbatim">/* This example code is placed in the public domain. */

#ifdef HAVE_CONFIG_H
#include &lt;config.h&gt;
#endif

#include &lt;stdio.h&gt;
#include &lt;stdlib.h&gt;
#include &lt;string.h&gt;
#include &lt;sys/types.h&gt;
#include &lt;sys/socket.h&gt;
#include &lt;arpa/inet.h&gt;
#include &lt;unistd.h&gt;
#include &lt;assert.h&gt;
#include &lt;gnutls/gnutls.h&gt;
#include &lt;gnutls/x509.h&gt;
#include &lt;gnutls/abstract.h&gt;
#include &lt;sys/types.h&gt;
#include &lt;sys/stat.h&gt;
#include &lt;fcntl.h&gt;

/* A TLS client that loads the certificate and key.
 */

#define CHECK(x) assert((x) &gt;= 0)

#define MAX_BUF 1024
#define MSG &quot;GET / HTTP/1.0\r\n\r\n&quot;

#define CERT_FILE &quot;cert.pem&quot;
#define KEY_FILE &quot;key.pem&quot;
#define CAFILE &quot;/etc/ssl/certs/ca-certificates.crt&quot;

extern int tcp_connect(void);
extern void tcp_close(int sd);

static int cert_callback(gnutls_session_t session,
			 const gnutls_datum_t *req_ca_rdn, int nreqs,
			 const gnutls_pk_algorithm_t *sign_algos,
			 int sign_algos_length, gnutls_pcert_st **pcert,
			 unsigned int *pcert_length, gnutls_privkey_t *pkey);

gnutls_pcert_st pcrt;
gnutls_privkey_t key;

/* Load the certificate and the private key.
 */
static void load_keys(void)
{
	gnutls_datum_t data;

	CHECK(gnutls_load_file(CERT_FILE, &amp;data));

	CHECK(gnutls_pcert_import_x509_raw(&amp;pcrt, &amp;data, GNUTLS_X509_FMT_PEM,
					   0));

	gnutls_free(data.data);

	CHECK(gnutls_load_file(KEY_FILE, &amp;data));

	CHECK(gnutls_privkey_init(&amp;key));

	CHECK(gnutls_privkey_import_x509_raw(key, &amp;data, GNUTLS_X509_FMT_PEM,
					     NULL, 0));
	gnutls_free(data.data);
}

int main(void)
{
	int ret, sd, ii;
	gnutls_session_t session;
	char buffer[MAX_BUF + 1];
	gnutls_certificate_credentials_t xcred;

	if (gnutls_check_version(&quot;3.1.4&quot;) == NULL) {
		fprintf(stderr,
			&quot;GnuTLS 3.1.4 or later is required for this example\n&quot;);
		exit(1);
	}

	/* for backwards compatibility with gnutls &lt; 3.3.0 */
	CHECK(gnutls_global_init());

	load_keys();

	/* X509 stuff */
	CHECK(gnutls_certificate_allocate_credentials(&amp;xcred));

	/* sets the trusted cas file
	 */
	CHECK(gnutls_certificate_set_x509_trust_file(xcred, CAFILE,
						     GNUTLS_X509_FMT_PEM));

	gnutls_certificate_set_retrieve_function2(xcred, cert_callback);

	/* Initialize TLS session 
	 */
	CHECK(gnutls_init(&amp;session, GNUTLS_CLIENT));

	/* Use default priorities */
	CHECK(gnutls_set_default_priority(session));

	/* put the x509 credentials to the current session
	 */
	CHECK(gnutls_credentials_set(session, GNUTLS_CRD_CERTIFICATE, xcred));

	/* connect to the peer
	 */
	sd = tcp_connect();

	gnutls_transport_set_int(session, sd);

	/* Perform the TLS handshake
	 */
	ret = gnutls_handshake(session);

	if (ret &lt; 0) {
		fprintf(stderr, &quot;*** Handshake failed\n&quot;);
		gnutls_perror(ret);
		goto end;
	} else {
		char *desc;

		desc = gnutls_session_get_desc(session);
		printf(&quot;- Session info: %s\n&quot;, desc);
		gnutls_free(desc);
	}

	CHECK(gnutls_record_send(session, MSG, strlen(MSG)));

	ret = gnutls_record_recv(session, buffer, MAX_BUF);
	if (ret == 0) {
		printf(&quot;- Peer has closed the TLS connection\n&quot;);
		goto end;
	} else if (ret &lt; 0) {
		fprintf(stderr, &quot;*** Error: %s\n&quot;, gnutls_strerror(ret));
		goto end;
	}

	printf(&quot;- Received %d bytes: &quot;, ret);
	for (ii = 0; ii &lt; ret; ii++) {
		fputc(buffer[ii], stdout);
	}
	fputs(&quot;\n&quot;, stdout);

	CHECK(gnutls_bye(session, GNUTLS_SHUT_RDWR));

end:

	tcp_close(sd);

	gnutls_deinit(session);

	gnutls_certificate_free_credentials(xcred);

	gnutls_global_deinit();

	return 0;
}

/* This callback should be associated with a session by calling
 * gnutls_certificate_client_set_retrieve_function( session, cert_callback),
 * before a handshake.
 */

static int cert_callback(gnutls_session_t session,
			 const gnutls_datum_t *req_ca_rdn, int nreqs,
			 const gnutls_pk_algorithm_t *sign_algos,
			 int sign_algos_length, gnutls_pcert_st **pcert,
			 unsigned int *pcert_length, gnutls_privkey_t *pkey)
{
	char issuer_dn[256];
	int i, ret;
	size_t len;
	gnutls_certificate_type_t type;

	/* Print the server's trusted CAs
	 */
	if (nreqs &gt; 0)
		printf(&quot;- Server's trusted authorities:\n&quot;);
	else
		printf(&quot;- Server did not send us any trusted authorities names.\n&quot;);

	/* print the names (if any) */
	for (i = 0; i &lt; nreqs; i++) {
		len = sizeof(issuer_dn);
		ret = gnutls_x509_rdn_get(&amp;req_ca_rdn[i], issuer_dn, &amp;len);
		if (ret &gt;= 0) {
			printf(&quot;   [%d]: &quot;, i);
			printf(&quot;%s\n&quot;, issuer_dn);
		}
	}

	/* Select a certificate and return it.
	 * The certificate must be of any of the &quot;sign algorithms&quot;
	 * supported by the server.
	 */
	type = gnutls_certificate_type_get(session);
	if (type == GNUTLS_CRT_X509) {
		*pcert_length = 1;
		*pcert = &amp;pcrt;
		*pkey = key;
	} else {
		return -1;
	}

	return 0;
}
</pre>

<hr>
</div>
<div class="subsection-level-extent" id="Obtaining-session-information">
<div class="nav-panel">
<p>
Next: <a href="#Advanced-certificate-verification-example" accesskey="n" rel="next">Advanced certificate verification</a>, Previous: <a href="#Using-a-callback-to-select-the-certificate-to-use" accesskey="p" rel="prev">Using a callback to select the certificate to use</a>, Up: <a href="#More-advanced-client-and-servers" accesskey="u" rel="up">More advanced client and servers</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Obtaining-session-information-1"><span>7.3.3 Obtaining session information<a class="copiable-link" href="#Obtaining-session-information-1"> &para;</a></span></h4>

<p>Most of the times it is desirable to know the security properties of
the current established session.  This includes the underlying ciphers
and the protocols involved.  That is the purpose of the following
function.  Note that this function will print meaningful values only
if called after a successful <a class="ref" href="#gnutls_005fhandshake">gnutls_handshake</a>.
</p>
<pre class="verbatim">/* This example code is placed in the public domain. */

#ifdef HAVE_CONFIG_H
#include &lt;config.h&gt;
#endif

#include &lt;stdio.h&gt;
#include &lt;stdlib.h&gt;
#include &lt;gnutls/gnutls.h&gt;
#include &lt;gnutls/x509.h&gt;

#include &quot;examples.h&quot;

/* This function will print some details of the
 * given session.
 */
int print_info(gnutls_session_t session)
{
	gnutls_credentials_type_t cred;
	gnutls_kx_algorithm_t kx;
	int dhe, ecdh, group;
	char *desc;

	/* get a description of the session connection, protocol,
	 * cipher/key exchange */
	desc = gnutls_session_get_desc(session);
	if (desc != NULL) {
		printf(&quot;- Session: %s\n&quot;, desc);
	}

	dhe = ecdh = 0;

	kx = gnutls_kx_get(session);

	/* Check the authentication type used and switch
	 * to the appropriate.
	 */
	cred = gnutls_auth_get_type(session);
	switch (cred) {
#ifdef ENABLE_SRP
	case GNUTLS_CRD_SRP:
		printf(&quot;- SRP session with username %s\n&quot;,
		       gnutls_srp_server_get_username(session));
		break;
#endif

	case GNUTLS_CRD_PSK:
		/* This returns NULL in server side.
		 */
		if (gnutls_psk_client_get_hint(session) != NULL)
			printf(&quot;- PSK authentication. PSK hint '%s'\n&quot;,
			       gnutls_psk_client_get_hint(session));
		/* This returns NULL in client side.
		 */
		if (gnutls_psk_server_get_username(session) != NULL)
			printf(&quot;- PSK authentication. Connected as '%s'\n&quot;,
			       gnutls_psk_server_get_username(session));

		if (kx == GNUTLS_KX_ECDHE_PSK)
			ecdh = 1;
		else if (kx == GNUTLS_KX_DHE_PSK)
			dhe = 1;
		break;

	case GNUTLS_CRD_ANON: /* anonymous authentication */

		printf(&quot;- Anonymous authentication.\n&quot;);
		if (kx == GNUTLS_KX_ANON_ECDH)
			ecdh = 1;
		else if (kx == GNUTLS_KX_ANON_DH)
			dhe = 1;
		break;

	case GNUTLS_CRD_CERTIFICATE: /* certificate authentication */

		/* Check if we have been using ephemeral Diffie-Hellman.
		 */
		if (kx == GNUTLS_KX_DHE_RSA || kx == GNUTLS_KX_DHE_DSS)
			dhe = 1;
		else if (kx == GNUTLS_KX_ECDHE_RSA ||
			 kx == GNUTLS_KX_ECDHE_ECDSA)
			ecdh = 1;

		/* if the certificate list is available, then
		 * print some information about it.
		 */
		print_x509_certificate_info(session);
		break;
	default:
		break;
	} /* switch */

	/* read the negotiated group - if any */
	group = gnutls_group_get(session);
	if (group != 0) {
		printf(&quot;- Negotiated group %s\n&quot;, gnutls_group_get_name(group));
	} else {
		if (ecdh != 0)
			printf(&quot;- Ephemeral ECDH using curve %s\n&quot;,
			       gnutls_ecc_curve_get_name(
				       gnutls_ecc_curve_get(session)));
		else if (dhe != 0)
			printf(&quot;- Ephemeral DH using prime of %d bits\n&quot;,
			       gnutls_dh_get_prime_bits(session));
	}

	return 0;
}
</pre>


<hr>
</div>
<div class="subsection-level-extent" id="Advanced-certificate-verification-example">
<div class="nav-panel">
<p>
Next: <a href="#Client-example-with-PSK-authentication" accesskey="n" rel="next">Client example with <abbr class="acronym">PSK</abbr> authentication</a>, Previous: <a href="#Obtaining-session-information" accesskey="p" rel="prev">Obtaining session information</a>, Up: <a href="#More-advanced-client-and-servers" accesskey="u" rel="up">More advanced client and servers</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Advanced-certificate-verification-2"><span>7.3.4 Advanced certificate verification<a class="copiable-link" href="#Advanced-certificate-verification-2"> &para;</a></span></h4>
<a class="anchor" id="ex_002dverify2"></a>
<p>An example is listed below which uses the high level verification
functions to verify a given certificate chain against a set of CAs
and CRLs.
</p>
<pre class="verbatim">/* This example code is placed in the public domain. */

#ifdef HAVE_CONFIG_H
#include &lt;config.h&gt;
#endif

#include &lt;stdio.h&gt;
#include &lt;stdlib.h&gt;
#include &lt;string.h&gt;
#include &lt;assert.h&gt;
#include &lt;gnutls/gnutls.h&gt;
#include &lt;gnutls/x509.h&gt;

#include &quot;examples.h&quot;

#define CHECK(x) assert((x) &gt;= 0)

/* All the available CRLs
 */
gnutls_x509_crl_t *crl_list;
int crl_list_size;

/* All the available trusted CAs
 */
gnutls_x509_crt_t *ca_list;
int ca_list_size;

static int print_details_func(gnutls_x509_crt_t cert, gnutls_x509_crt_t issuer,
			      gnutls_x509_crl_t crl,
			      unsigned int verification_output);

/* This function will try to verify the peer's certificate chain, and
 * also check if the hostname matches.
 */
void verify_certificate_chain(const char *hostname,
			      const gnutls_datum_t *cert_chain,
			      int cert_chain_length)
{
	int i;
	gnutls_x509_trust_list_t tlist;
	gnutls_x509_crt_t *cert;
	gnutls_datum_t txt;
	unsigned int output;

	/* Initialize the trusted certificate list. This should be done
	 * once on initialization. gnutls_x509_crt_list_import2() and
	 * gnutls_x509_crl_list_import2() can be used to load them.
	 */
	CHECK(gnutls_x509_trust_list_init(&amp;tlist, 0));

	CHECK(gnutls_x509_trust_list_add_cas(tlist, ca_list, ca_list_size, 0));
	CHECK(gnutls_x509_trust_list_add_crls(tlist, crl_list, crl_list_size,
					      GNUTLS_TL_VERIFY_CRL, 0));

	cert = gnutls_calloc(cert_chain_length, sizeof(*cert));
	assert(cert != NULL);

	/* Import all the certificates in the chain to
	 * native certificate format.
	 */
	for (i = 0; i &lt; cert_chain_length; i++) {
		CHECK(gnutls_x509_crt_init(&amp;cert[i]));
		CHECK(gnutls_x509_crt_import(cert[i], &amp;cert_chain[i],
					     GNUTLS_X509_FMT_DER));
	}

	CHECK(gnutls_x509_trust_list_verify_named_crt(
		tlist, cert[0], hostname, strlen(hostname),
		GNUTLS_VERIFY_DISABLE_CRL_CHECKS, &amp;output, print_details_func));

	/* if this certificate is not explicitly trusted verify against CAs 
	 */
	if (output != 0) {
		CHECK(gnutls_x509_trust_list_verify_crt(
			tlist, cert, cert_chain_length, 0, &amp;output,
			print_details_func));
	}

	if (output &amp; GNUTLS_CERT_INVALID) {
		fprintf(stderr, &quot;Not trusted\n&quot;);
		CHECK(gnutls_certificate_verification_status_print(
			output, GNUTLS_CRT_X509, &amp;txt, 0));

		fprintf(stderr, &quot;Error: %s\n&quot;, txt.data);
		gnutls_free(txt.data);
	} else
		fprintf(stderr, &quot;Trusted\n&quot;);

	/* Check if the name in the first certificate matches our destination!
	 */
	if (!gnutls_x509_crt_check_hostname(cert[0], hostname)) {
		printf(&quot;The certificate's owner does not match hostname '%s'\n&quot;,
		       hostname);
	}

	for (i = 0; i &lt; cert_chain_length; i++) {
		gnutls_x509_crt_deinit(cert[i]);
	}
	gnutls_free(cert);

	gnutls_x509_trust_list_deinit(tlist, 1);

	return;
}

static int print_details_func(gnutls_x509_crt_t cert, gnutls_x509_crt_t issuer,
			      gnutls_x509_crl_t crl,
			      unsigned int verification_output)
{
	char name[512];
	char issuer_name[512];
	size_t name_size;
	size_t issuer_name_size;

	issuer_name_size = sizeof(issuer_name);
	gnutls_x509_crt_get_issuer_dn(cert, issuer_name, &amp;issuer_name_size);

	name_size = sizeof(name);
	gnutls_x509_crt_get_dn(cert, name, &amp;name_size);

	fprintf(stdout, &quot;\tSubject: %s\n&quot;, name);
	fprintf(stdout, &quot;\tIssuer: %s\n&quot;, issuer_name);

	if (issuer != NULL) {
		issuer_name_size = sizeof(issuer_name);
		gnutls_x509_crt_get_dn(issuer, issuer_name, &amp;issuer_name_size);

		fprintf(stdout, &quot;\tVerified against: %s\n&quot;, issuer_name);
	}

	if (crl != NULL) {
		issuer_name_size = sizeof(issuer_name);
		gnutls_x509_crl_get_issuer_dn(crl, issuer_name,
					      &amp;issuer_name_size);

		fprintf(stdout, &quot;\tVerified against CRL of: %s\n&quot;, issuer_name);
	}

	fprintf(stdout, &quot;\tVerification output: %x\n\n&quot;, verification_output);

	return 0;
}
</pre>

<hr>
</div>
<div class="subsection-level-extent" id="Client-example-with-PSK-authentication">
<div class="nav-panel">
<p>
Next: <a href="#Client-example-with-SRP-authentication" accesskey="n" rel="next">Client example with <abbr class="acronym">SRP</abbr> authentication</a>, Previous: <a href="#Advanced-certificate-verification-example" accesskey="p" rel="prev">Advanced certificate verification</a>, Up: <a href="#More-advanced-client-and-servers" accesskey="u" rel="up">More advanced client and servers</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Client-example-with-PSK-authentication-1"><span>7.3.5 Client example with <abbr class="acronym">PSK</abbr> authentication<a class="copiable-link" href="#Client-example-with-PSK-authentication-1"> &para;</a></span></h4>

<p>The following client is a very simple <abbr class="acronym">PSK</abbr> <abbr class="acronym">TLS</abbr>
client which connects to a server and authenticates using a
<em class="emph">username</em> and a <em class="emph">key</em>.
</p>
<pre class="verbatim">/* This example code is placed in the public domain. */

#ifdef HAVE_CONFIG_H
#include &lt;config.h&gt;
#endif

#include &lt;stdio.h&gt;
#include &lt;stdlib.h&gt;
#include &lt;string.h&gt;
#include &lt;sys/types.h&gt;
#include &lt;sys/socket.h&gt;
#include &lt;arpa/inet.h&gt;
#include &lt;unistd.h&gt;
#include &lt;assert.h&gt;
#include &lt;gnutls/gnutls.h&gt;

/* A very basic TLS client, with PSK authentication.
 */

#define CHECK(x) assert((x) &gt;= 0)
#define LOOP_CHECK(rval, cmd)                                             \
	do {                                                              \
		rval = cmd;                                               \
	} while (rval == GNUTLS_E_AGAIN || rval == GNUTLS_E_INTERRUPTED); \
	assert(rval &gt;= 0)

#define MAX_BUF 1024
#define MSG &quot;GET / HTTP/1.0\r\n\r\n&quot;

extern int tcp_connect(void);
extern void tcp_close(int sd);

int main(void)
{
	int ret, sd, ii;
	gnutls_session_t session;
	char buffer[MAX_BUF + 1];
	const char *err;
	gnutls_psk_client_credentials_t pskcred;
	const gnutls_datum_t key = { (void *)&quot;DEADBEEF&quot;, 8 };

	if (gnutls_check_version(&quot;3.6.3&quot;) == NULL) {
		fprintf(stderr,
			&quot;GnuTLS 3.6.3 or later is required for this example\n&quot;);
		exit(1);
	}

	CHECK(gnutls_global_init());

	CHECK(gnutls_psk_allocate_client_credentials(&amp;pskcred));
	CHECK(gnutls_psk_set_client_credentials(pskcred, &quot;test&quot;, &amp;key,
						GNUTLS_PSK_KEY_HEX));

	/* Initialize TLS session
	 */
	CHECK(gnutls_init(&amp;session, GNUTLS_CLIENT));

	ret = gnutls_set_default_priority_append(
		session, &quot;-KX-ALL:+ECDHE-PSK:+DHE-PSK:+PSK&quot;, &amp;err, 0);

	/* Alternative for pre-3.6.3 versions:
	 * gnutls_priority_set_direct(session, &quot;NORMAL:+ECDHE-PSK:+DHE-PSK:+PSK&quot;, &amp;err)
	 */
	if (ret &lt; 0) {
		if (ret == GNUTLS_E_INVALID_REQUEST) {
			fprintf(stderr, &quot;Syntax error at: %s\n&quot;, err);
		}
		exit(1);
	}

	/* put the x509 credentials to the current session
	 */
	CHECK(gnutls_credentials_set(session, GNUTLS_CRD_PSK, pskcred));

	/* connect to the peer
	 */
	sd = tcp_connect();

	gnutls_transport_set_int(session, sd);
	gnutls_handshake_set_timeout(session, GNUTLS_DEFAULT_HANDSHAKE_TIMEOUT);

	/* Perform the TLS handshake
	 */
	do {
		ret = gnutls_handshake(session);
	} while (ret &lt; 0 &amp;&amp; gnutls_error_is_fatal(ret) == 0);

	if (ret &lt; 0) {
		fprintf(stderr, &quot;*** Handshake failed\n&quot;);
		gnutls_perror(ret);
		goto end;
	} else {
		char *desc;

		desc = gnutls_session_get_desc(session);
		printf(&quot;- Session info: %s\n&quot;, desc);
		gnutls_free(desc);
	}

	LOOP_CHECK(ret, gnutls_record_send(session, MSG, strlen(MSG)));

	LOOP_CHECK(ret, gnutls_record_recv(session, buffer, MAX_BUF));
	if (ret == 0) {
		printf(&quot;- Peer has closed the TLS connection\n&quot;);
		goto end;
	} else if (ret &lt; 0 &amp;&amp; gnutls_error_is_fatal(ret) == 0) {
		fprintf(stderr, &quot;*** Warning: %s\n&quot;, gnutls_strerror(ret));
	} else if (ret &lt; 0) {
		fprintf(stderr, &quot;*** Error: %s\n&quot;, gnutls_strerror(ret));
		goto end;
	}

	if (ret &gt; 0) {
		printf(&quot;- Received %d bytes: &quot;, ret);
		for (ii = 0; ii &lt; ret; ii++) {
			fputc(buffer[ii], stdout);
		}
		fputs(&quot;\n&quot;, stdout);
	}

	CHECK(gnutls_bye(session, GNUTLS_SHUT_RDWR));

end:

	tcp_close(sd);

	gnutls_deinit(session);

	gnutls_psk_free_client_credentials(pskcred);

	gnutls_global_deinit();

	return 0;
}
</pre>

<hr>
</div>
<div class="subsection-level-extent" id="Client-example-with-SRP-authentication">
<div class="nav-panel">
<p>
Next: <a href="#Legacy-client-example-with-X_002e509-certificate-support" accesskey="n" rel="next">Legacy client example with <abbr class="acronym">X.509</abbr> certificate support</a>, Previous: <a href="#Client-example-with-PSK-authentication" accesskey="p" rel="prev">Client example with <abbr class="acronym">PSK</abbr> authentication</a>, Up: <a href="#More-advanced-client-and-servers" accesskey="u" rel="up">More advanced client and servers</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Client-example-with-SRP-authentication-1"><span>7.3.6 Client example with <abbr class="acronym">SRP</abbr> authentication<a class="copiable-link" href="#Client-example-with-SRP-authentication-1"> &para;</a></span></h4>

<p>The following client is a very simple <abbr class="acronym">SRP</abbr> <abbr class="acronym">TLS</abbr>
client which connects to a server and authenticates using a
<em class="emph">username</em> and a <em class="emph">password</em>. The server may authenticate
itself using a certificate, and in that case it has to be verified.
</p>
<pre class="verbatim">/* This example code is placed in the public domain. */

#ifdef HAVE_CONFIG_H
#include &lt;config.h&gt;
#endif

#include &lt;stdio.h&gt;
#include &lt;stdlib.h&gt;
#include &lt;string.h&gt;
#include &lt;gnutls/gnutls.h&gt;

/* Those functions are defined in other examples.
 */
extern void check_alert(gnutls_session_t session, int ret);
extern int tcp_connect(void);
extern void tcp_close(int sd);

#define MAX_BUF 1024
#define USERNAME &quot;user&quot;
#define PASSWORD &quot;pass&quot;
#define CAFILE &quot;/etc/ssl/certs/ca-certificates.crt&quot;
#define MSG &quot;GET / HTTP/1.0\r\n\r\n&quot;

int main(void)
{
	int ret;
	int sd, ii;
	gnutls_session_t session;
	char buffer[MAX_BUF + 1];
	gnutls_srp_client_credentials_t srp_cred;
	gnutls_certificate_credentials_t cert_cred;

	if (gnutls_check_version(&quot;3.1.4&quot;) == NULL) {
		fprintf(stderr,
			&quot;GnuTLS 3.1.4 or later is required for this example\n&quot;);
		exit(1);
	}

	/* for backwards compatibility with gnutls &lt; 3.3.0 */
	gnutls_global_init();

	gnutls_srp_allocate_client_credentials(&amp;srp_cred);
	gnutls_certificate_allocate_credentials(&amp;cert_cred);

	gnutls_certificate_set_x509_trust_file(cert_cred, CAFILE,
					       GNUTLS_X509_FMT_PEM);
	gnutls_srp_set_client_credentials(srp_cred, USERNAME, PASSWORD);

	/* connects to server
	 */
	sd = tcp_connect();

	/* Initialize TLS session
	 */
	gnutls_init(&amp;session, GNUTLS_CLIENT);

	/* Set the priorities.
	 */
	gnutls_priority_set_direct(session, &quot;NORMAL:+SRP:+SRP-RSA:+SRP-DSS&quot;,
				   NULL);

	/* put the SRP credentials to the current session
	 */
	gnutls_credentials_set(session, GNUTLS_CRD_SRP, srp_cred);
	gnutls_credentials_set(session, GNUTLS_CRD_CERTIFICATE, cert_cred);

	gnutls_transport_set_int(session, sd);
	gnutls_handshake_set_timeout(session, GNUTLS_DEFAULT_HANDSHAKE_TIMEOUT);

	/* Perform the TLS handshake
	 */
	do {
		ret = gnutls_handshake(session);
	} while (ret &lt; 0 &amp;&amp; gnutls_error_is_fatal(ret) == 0);

	if (ret &lt; 0) {
		fprintf(stderr, &quot;*** Handshake failed\n&quot;);
		gnutls_perror(ret);
		goto end;
	} else {
		char *desc;

		desc = gnutls_session_get_desc(session);
		printf(&quot;- Session info: %s\n&quot;, desc);
		gnutls_free(desc);
	}

	gnutls_record_send(session, MSG, strlen(MSG));

	ret = gnutls_record_recv(session, buffer, MAX_BUF);
	if (gnutls_error_is_fatal(ret) != 0 || ret == 0) {
		if (ret == 0) {
			printf(&quot;- Peer has closed the GnuTLS connection\n&quot;);
			goto end;
		} else {
			fprintf(stderr, &quot;*** Error: %s\n&quot;,
				gnutls_strerror(ret));
			goto end;
		}
	} else
		check_alert(session, ret);

	if (ret &gt; 0) {
		printf(&quot;- Received %d bytes: &quot;, ret);
		for (ii = 0; ii &lt; ret; ii++) {
			fputc(buffer[ii], stdout);
		}
		fputs(&quot;\n&quot;, stdout);
	}
	gnutls_bye(session, GNUTLS_SHUT_RDWR);

end:

	tcp_close(sd);

	gnutls_deinit(session);

	gnutls_srp_free_client_credentials(srp_cred);
	gnutls_certificate_free_credentials(cert_cred);

	gnutls_global_deinit();

	return 0;
}
</pre>

<hr>
</div>
<div class="subsection-level-extent" id="Legacy-client-example-with-X_002e509-certificate-support">
<div class="nav-panel">
<p>
Next: <a href="#Client-example-in-C_002b_002b" accesskey="n" rel="next">Client example using the C++ API</a>, Previous: <a href="#Client-example-with-SRP-authentication" accesskey="p" rel="prev">Client example with <abbr class="acronym">SRP</abbr> authentication</a>, Up: <a href="#More-advanced-client-and-servers" accesskey="u" rel="up">More advanced client and servers</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Legacy-client-example-with-X_002e509-certificate-support-1"><span>7.3.7 Legacy client example with <abbr class="acronym">X.509</abbr> certificate support<a class="copiable-link" href="#Legacy-client-example-with-X_002e509-certificate-support-1"> &para;</a></span></h4>
<a class="anchor" id="ex_002dverify_002dlegacy"></a>
<p>For applications that need to maintain compatibility with the GnuTLS 3.1.x
library, this client example is identical to <a class="ref" href="#Client-example-with-X_002e509-certificate-support">Client example with <abbr class="acronym">X.509</abbr> certificate support</a>
but utilizes APIs that were available in GnuTLS 3.1.4. 
</p>
<pre class="verbatim">/* This example code is placed in the public domain. */

#ifdef HAVE_CONFIG_H
#include &lt;config.h&gt;
#endif

#include &lt;stdio.h&gt;
#include &lt;stdlib.h&gt;
#include &lt;string.h&gt;
#include &lt;assert.h&gt;
#include &lt;gnutls/gnutls.h&gt;
#include &lt;gnutls/x509.h&gt;
#include &quot;examples.h&quot;

/* A very basic TLS client, with X.509 authentication and server certificate
 * verification utilizing the GnuTLS 3.1.x API. 
 * Note that error recovery is minimal for simplicity.
 */

#define CHECK(x) assert((x) &gt;= 0)
#define LOOP_CHECK(rval, cmd)                                             \
	do {                                                              \
		rval = cmd;                                               \
	} while (rval == GNUTLS_E_AGAIN || rval == GNUTLS_E_INTERRUPTED); \
	assert(rval &gt;= 0)

#define MAX_BUF 1024
#define CAFILE &quot;/etc/ssl/certs/ca-certificates.crt&quot;
#define MSG &quot;GET / HTTP/1.0\r\n\r\n&quot;

extern int tcp_connect(void);
extern void tcp_close(int sd);
static int _verify_certificate_callback(gnutls_session_t session);

int main(void)
{
	int ret, sd, ii;
	gnutls_session_t session;
	char buffer[MAX_BUF + 1];
	gnutls_certificate_credentials_t xcred;

	if (gnutls_check_version(&quot;3.1.4&quot;) == NULL) {
		fprintf(stderr,
			&quot;GnuTLS 3.1.4 or later is required for this example\n&quot;);
		exit(1);
	}

	CHECK(gnutls_global_init());

	/* X509 stuff */
	CHECK(gnutls_certificate_allocate_credentials(&amp;xcred));

	/* sets the trusted cas file
	 */
	CHECK(gnutls_certificate_set_x509_trust_file(xcred, CAFILE,
						     GNUTLS_X509_FMT_PEM));
	gnutls_certificate_set_verify_function(xcred,
					       _verify_certificate_callback);

	/* If client holds a certificate it can be set using the following:
	 *
	 gnutls_certificate_set_x509_key_file (xcred, 
	 &quot;cert.pem&quot;, &quot;key.pem&quot;, 
	 GNUTLS_X509_FMT_PEM); 
	 */

	/* Initialize TLS session 
	 */
	CHECK(gnutls_init(&amp;session, GNUTLS_CLIENT));

	gnutls_session_set_ptr(session, (void *)&quot;www.example.com&quot;);

	gnutls_server_name_set(session, GNUTLS_NAME_DNS, &quot;www.example.com&quot;,
			       strlen(&quot;www.example.com&quot;));

	/* use default priorities */
	CHECK(gnutls_set_default_priority(session));
#if 0
	/* if more fine-graned control is required */
	ret = gnutls_priority_set_direct(session, &quot;NORMAL&quot;, &amp;err);
	if (ret &lt; 0) {
		if (ret == GNUTLS_E_INVALID_REQUEST) {
			fprintf(stderr, &quot;Syntax error at: %s\n&quot;, err);
		}
		exit(1);
	}
#endif

	/* put the x509 credentials to the current session
	 */
	CHECK(gnutls_credentials_set(session, GNUTLS_CRD_CERTIFICATE, xcred));

	/* connect to the peer
	 */
	sd = tcp_connect();

	gnutls_transport_set_int(session, sd);
	gnutls_handshake_set_timeout(session, GNUTLS_DEFAULT_HANDSHAKE_TIMEOUT);

	/* Perform the TLS handshake
	 */
	do {
		ret = gnutls_handshake(session);
	} while (ret &lt; 0 &amp;&amp; gnutls_error_is_fatal(ret) == 0);

	if (ret &lt; 0) {
		fprintf(stderr, &quot;*** Handshake failed\n&quot;);
		gnutls_perror(ret);
		goto end;
	} else {
		char *desc;

		desc = gnutls_session_get_desc(session);
		printf(&quot;- Session info: %s\n&quot;, desc);
		gnutls_free(desc);
	}

	LOOP_CHECK(ret, gnutls_record_send(session, MSG, strlen(MSG)));

	LOOP_CHECK(ret, gnutls_record_recv(session, buffer, MAX_BUF));
	if (ret == 0) {
		printf(&quot;- Peer has closed the TLS connection\n&quot;);
		goto end;
	} else if (ret &lt; 0 &amp;&amp; gnutls_error_is_fatal(ret) == 0) {
		fprintf(stderr, &quot;*** Warning: %s\n&quot;, gnutls_strerror(ret));
	} else if (ret &lt; 0) {
		fprintf(stderr, &quot;*** Error: %s\n&quot;, gnutls_strerror(ret));
		goto end;
	}

	if (ret &gt; 0) {
		printf(&quot;- Received %d bytes: &quot;, ret);
		for (ii = 0; ii &lt; ret; ii++) {
			fputc(buffer[ii], stdout);
		}
		fputs(&quot;\n&quot;, stdout);
	}

	CHECK(gnutls_bye(session, GNUTLS_SHUT_RDWR));

end:

	tcp_close(sd);

	gnutls_deinit(session);

	gnutls_certificate_free_credentials(xcred);

	gnutls_global_deinit();

	return 0;
}

/* This function will verify the peer's certificate, and check
 * if the hostname matches, as well as the activation, expiration dates.
 */
static int _verify_certificate_callback(gnutls_session_t session)
{
	unsigned int status;
	int type;
	const char *hostname;
	gnutls_datum_t out;

	/* read hostname */
	hostname = gnutls_session_get_ptr(session);

	/* This verification function uses the trusted CAs in the credentials
	 * structure. So you must have installed one or more CA certificates.
	 */

	CHECK(gnutls_certificate_verify_peers3(session, hostname, &amp;status));

	type = gnutls_certificate_type_get(session);

	CHECK(gnutls_certificate_verification_status_print(status, type, &amp;out,
							   0));

	printf(&quot;%s&quot;, out.data);

	gnutls_free(out.data);

	if (status != 0) /* Certificate is not trusted */
		return GNUTLS_E_CERTIFICATE_ERROR;

	/* notify gnutls to continue handshake normally */
	return 0;
}
</pre>
<hr>
</div>
<div class="subsection-level-extent" id="Client-example-in-C_002b_002b">
<div class="nav-panel">
<p>
Next: <a href="#Echo-server-with-PSK-authentication" accesskey="n" rel="next">Echo server with <abbr class="acronym">PSK</abbr> authentication</a>, Previous: <a href="#Legacy-client-example-with-X_002e509-certificate-support" accesskey="p" rel="prev">Legacy client example with <abbr class="acronym">X.509</abbr> certificate support</a>, Up: <a href="#More-advanced-client-and-servers" accesskey="u" rel="up">More advanced client and servers</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Client-example-using-the-C_002b_002b-API"><span>7.3.8 Client example using the C++ API<a class="copiable-link" href="#Client-example-using-the-C_002b_002b-API"> &para;</a></span></h4>

<p>The following client is a simple example of a client client utilizing
the GnuTLS C++ API.
</p>
<pre class="verbatim">#include &lt;config.h&gt;
#include &lt;iostream&gt;
#include &lt;stdexcept&gt;
#include &lt;gnutls/gnutls.h&gt;
#include &lt;gnutls/gnutlsxx.h&gt;
#include &lt;cstring&gt; /* for strlen */

/* A very basic TLS client, with anonymous authentication.
 * written by Eduardo Villanueva Che.
 */

#define MAX_BUF 1024
#define SA struct sockaddr

#define CAFILE &quot;ca.pem&quot;
#define MSG &quot;GET / HTTP/1.0\r\n\r\n&quot;

extern &quot;C&quot;
{
    int tcp_connect(void);
    void tcp_close(int sd);
}


int main(void)
{
    int sd = -1;
    gnutls_global_init();

    try
    {

        /* Allow connections to servers that have OpenPGP keys as well.
         */
        gnutls::client_session session;

        /* X509 stuff */
        gnutls::certificate_credentials credentials;


        /* sets the trusted cas file
         */
        credentials.set_x509_trust_file(CAFILE, GNUTLS_X509_FMT_PEM);
        /* put the x509 credentials to the current session
         */
        session.set_credentials(credentials);

        /* Use default priorities */
        session.set_priority (&quot;NORMAL&quot;, NULL);

        /* connect to the peer
         */
        sd = tcp_connect();
        session.set_transport_ptr((gnutls_transport_ptr_t) (ptrdiff_t)sd);

        /* Perform the TLS handshake
         */
        int ret = session.handshake();
        if (ret &lt; 0)
        {
            throw std::runtime_error(&quot;Handshake failed&quot;);
        }
        else
        {
            std::cout &lt;&lt; &quot;- Handshake was completed&quot; &lt;&lt; std::endl;
        }

        session.send(MSG, strlen(MSG));
        char buffer[MAX_BUF + 1];
        ret = session.recv(buffer, MAX_BUF);
        if (ret == 0)
        {
            throw std::runtime_error(&quot;Peer has closed the TLS connection&quot;);
        }
        else if (ret &lt; 0)
        {
            throw std::runtime_error(gnutls_strerror(ret));
        }

        std::cout &lt;&lt; &quot;- Received &quot; &lt;&lt; ret &lt;&lt; &quot; bytes:&quot; &lt;&lt; std::endl;
        std::cout.write(buffer, ret);
        std::cout &lt;&lt; std::endl;

        session.bye(GNUTLS_SHUT_RDWR);
    }
    catch (std::exception &amp;ex)
    {
        std::cerr &lt;&lt; &quot;Exception caught: &quot; &lt;&lt; ex.what() &lt;&lt; std::endl;
    }

    if (sd != -1)
        tcp_close(sd);

    gnutls_global_deinit();

    return 0;
}
</pre>

<hr>
</div>
<div class="subsection-level-extent" id="Echo-server-with-PSK-authentication">
<div class="nav-panel">
<p>
Next: <a href="#Echo-server-with-SRP-authentication" accesskey="n" rel="next">Echo server with <abbr class="acronym">SRP</abbr> authentication</a>, Previous: <a href="#Client-example-in-C_002b_002b" accesskey="p" rel="prev">Client example using the C++ API</a>, Up: <a href="#More-advanced-client-and-servers" accesskey="u" rel="up">More advanced client and servers</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Echo-server-with-PSK-authentication-1"><span>7.3.9 Echo server with <abbr class="acronym">PSK</abbr> authentication<a class="copiable-link" href="#Echo-server-with-PSK-authentication-1"> &para;</a></span></h4>

<p>This is a server which supports <abbr class="acronym">PSK</abbr> authentication.
</p>
<pre class="verbatim">/* This example code is placed in the public domain. */

#ifdef HAVE_CONFIG_H
#include &lt;config.h&gt;
#endif

#include &lt;stdio.h&gt;
#include &lt;stdlib.h&gt;
#include &lt;errno.h&gt;
#include &lt;sys/types.h&gt;
#include &lt;sys/socket.h&gt;
#include &lt;arpa/inet.h&gt;
#include &lt;netinet/in.h&gt;
#include &lt;string.h&gt;
#include &lt;unistd.h&gt;
#include &lt;gnutls/gnutls.h&gt;

#define KEYFILE &quot;key.pem&quot;
#define CERTFILE &quot;cert.pem&quot;
#define CAFILE &quot;/etc/ssl/certs/ca-certificates.crt&quot;
#define CRLFILE &quot;crl.pem&quot;

#define LOOP_CHECK(rval, cmd) \
	do {                  \
		rval = cmd;   \
	} while (rval == GNUTLS_E_AGAIN || rval == GNUTLS_E_INTERRUPTED)

/* This is a sample TLS echo server, supporting X.509 and PSK
   authentication.
 */

#define SOCKET_ERR(err, s)  \
	if (err == -1) {    \
		perror(s);  \
		return (1); \
	}
#define MAX_BUF 1024
#define PORT 5556 /* listen to 5556 port */

static int pskfunc(gnutls_session_t session, const char *username,
		   gnutls_datum_t *key)
{
	printf(&quot;psk: username %s\n&quot;, username);
	key-&gt;data = gnutls_malloc(4);
	key-&gt;data[0] = 0xDE;
	key-&gt;data[1] = 0xAD;
	key-&gt;data[2] = 0xBE;
	key-&gt;data[3] = 0xEF;
	key-&gt;size = 4;
	return 0;
}

int main(void)
{
	int err, listen_sd;
	int sd, ret;
	struct sockaddr_in sa_serv;
	struct sockaddr_in sa_cli;
	socklen_t client_len;
	char topbuf[512];
	gnutls_session_t session;
	gnutls_certificate_credentials_t x509_cred;
	gnutls_psk_server_credentials_t psk_cred;
	gnutls_priority_t priority_cache;
	char buffer[MAX_BUF + 1];
	int optval = 1;
	int kx;

	if (gnutls_check_version(&quot;3.1.4&quot;) == NULL) {
		fprintf(stderr,
			&quot;GnuTLS 3.1.4 or later is required for this example\n&quot;);
		exit(1);
	}

	/* for backwards compatibility with gnutls &lt; 3.3.0 */
	gnutls_global_init();

	gnutls_certificate_allocate_credentials(&amp;x509_cred);
	gnutls_certificate_set_x509_trust_file(x509_cred, CAFILE,
					       GNUTLS_X509_FMT_PEM);

	gnutls_certificate_set_x509_crl_file(x509_cred, CRLFILE,
					     GNUTLS_X509_FMT_PEM);

	gnutls_certificate_set_x509_key_file(x509_cred, CERTFILE, KEYFILE,
					     GNUTLS_X509_FMT_PEM);

	gnutls_psk_allocate_server_credentials(&amp;psk_cred);
	gnutls_psk_set_server_credentials_function(psk_cred, pskfunc);

	/* pre-3.6.3 equivalent:
	 * gnutls_priority_init(&amp;priority_cache,
	 *                      &quot;NORMAL:+PSK:+ECDHE-PSK:+DHE-PSK&quot;,
	 *                      NULL);
	 */
	gnutls_priority_init2(&amp;priority_cache, &quot;+ECDHE-PSK:+DHE-PSK:+PSK&quot;, NULL,
			      GNUTLS_PRIORITY_INIT_DEF_APPEND);

	gnutls_certificate_set_known_dh_params(x509_cred,
					       GNUTLS_SEC_PARAM_MEDIUM);

	/* Socket operations
	 */
	listen_sd = socket(AF_INET, SOCK_STREAM, 0);
	SOCKET_ERR(listen_sd, &quot;socket&quot;);

	memset(&amp;sa_serv, '\0', sizeof(sa_serv));
	sa_serv.sin_family = AF_INET;
	sa_serv.sin_addr.s_addr = INADDR_ANY;
	sa_serv.sin_port = htons(PORT); /* Server Port number */

	setsockopt(listen_sd, SOL_SOCKET, SO_REUSEADDR, (void *)&amp;optval,
		   sizeof(int));

	err = bind(listen_sd, (struct sockaddr *)&amp;sa_serv, sizeof(sa_serv));
	SOCKET_ERR(err, &quot;bind&quot;);
	err = listen(listen_sd, 1024);
	SOCKET_ERR(err, &quot;listen&quot;);

	printf(&quot;Server ready. Listening to port '%d'.\n\n&quot;, PORT);

	client_len = sizeof(sa_cli);
	for (;;) {
		gnutls_init(&amp;session, GNUTLS_SERVER);
		gnutls_priority_set(session, priority_cache);
		gnutls_credentials_set(session, GNUTLS_CRD_CERTIFICATE,
				       x509_cred);
		gnutls_credentials_set(session, GNUTLS_CRD_PSK, psk_cred);

		/* request client certificate if any.
		 */
		gnutls_certificate_server_set_request(session,
						      GNUTLS_CERT_REQUEST);

		sd = accept(listen_sd, (struct sockaddr *)&amp;sa_cli, &amp;client_len);

		printf(&quot;- connection from %s, port %d\n&quot;,
		       inet_ntop(AF_INET, &amp;sa_cli.sin_addr, topbuf,
				 sizeof(topbuf)),
		       ntohs(sa_cli.sin_port));

		gnutls_transport_set_int(session, sd);
		LOOP_CHECK(ret, gnutls_handshake(session));
		if (ret &lt; 0) {
			close(sd);
			gnutls_deinit(session);
			fprintf(stderr, &quot;*** Handshake has failed (%s)\n\n&quot;,
				gnutls_strerror(ret));
			continue;
		}
		printf(&quot;- Handshake was completed\n&quot;);

		kx = gnutls_kx_get(session);
		if (kx == GNUTLS_KX_PSK || kx == GNUTLS_KX_DHE_PSK ||
		    kx == GNUTLS_KX_ECDHE_PSK) {
			printf(&quot;- User %s was connected\n&quot;,
			       gnutls_psk_server_get_username(session));
		}

		/* see the Getting peer's information example */
		/* print_info(session); */

		for (;;) {
			LOOP_CHECK(ret, gnutls_record_recv(session, buffer,
							   MAX_BUF));

			if (ret == 0) {
				printf(&quot;\n- Peer has closed the GnuTLS connection\n&quot;);
				break;
			} else if (ret &lt; 0 &amp;&amp; gnutls_error_is_fatal(ret) == 0) {
				fprintf(stderr, &quot;*** Warning: %s\n&quot;,
					gnutls_strerror(ret));
			} else if (ret &lt; 0) {
				fprintf(stderr,
					&quot;\n*** Received corrupted &quot;
					&quot;data(%d). Closing the connection.\n\n&quot;,
					ret);
				break;
			} else if (ret &gt; 0) {
				/* echo data back to the client
				 */
				gnutls_record_send(session, buffer, ret);
			}
		}
		printf(&quot;\n&quot;);
		/* do not wait for the peer to close the connection.
		 */
		LOOP_CHECK(ret, gnutls_bye(session, GNUTLS_SHUT_WR));

		close(sd);
		gnutls_deinit(session);
	}
	close(listen_sd);

	gnutls_certificate_free_credentials(x509_cred);
	gnutls_psk_free_server_credentials(psk_cred);

	gnutls_priority_deinit(priority_cache);

	gnutls_global_deinit();

	return 0;
}
</pre>

<hr>
</div>
<div class="subsection-level-extent" id="Echo-server-with-SRP-authentication">
<div class="nav-panel">
<p>
Next: <a href="#Echo-server-with-anonymous-authentication" accesskey="n" rel="next">Echo server with anonymous authentication</a>, Previous: <a href="#Echo-server-with-PSK-authentication" accesskey="p" rel="prev">Echo server with <abbr class="acronym">PSK</abbr> authentication</a>, Up: <a href="#More-advanced-client-and-servers" accesskey="u" rel="up">More advanced client and servers</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Echo-server-with-SRP-authentication-1"><span>7.3.10 Echo server with <abbr class="acronym">SRP</abbr> authentication<a class="copiable-link" href="#Echo-server-with-SRP-authentication-1"> &para;</a></span></h4>

<p>This is a server which supports <abbr class="acronym">SRP</abbr> authentication. It is
also possible to combine this functionality with a certificate
server. Here it is separate for simplicity.
</p>
<pre class="verbatim">/* This example code is placed in the public domain. */

#ifdef HAVE_CONFIG_H
#include &lt;config.h&gt;
#endif

#include &lt;stdio.h&gt;
#include &lt;stdlib.h&gt;
#include &lt;errno.h&gt;
#include &lt;sys/types.h&gt;
#include &lt;sys/socket.h&gt;
#include &lt;arpa/inet.h&gt;
#include &lt;netinet/in.h&gt;
#include &lt;string.h&gt;
#include &lt;unistd.h&gt;
#include &lt;gnutls/gnutls.h&gt;

#define SRP_PASSWD &quot;tpasswd&quot;
#define SRP_PASSWD_CONF &quot;tpasswd.conf&quot;

#define KEYFILE &quot;key.pem&quot;
#define CERTFILE &quot;cert.pem&quot;
#define CAFILE &quot;/etc/ssl/certs/ca-certificates.crt&quot;

#define LOOP_CHECK(rval, cmd) \
	do {                  \
		rval = cmd;   \
	} while (rval == GNUTLS_E_AGAIN || rval == GNUTLS_E_INTERRUPTED)

/* This is a sample TLS-SRP echo server.
 */

#define SOCKET_ERR(err, s)  \
	if (err == -1) {    \
		perror(s);  \
		return (1); \
	}
#define MAX_BUF 1024
#define PORT 5556 /* listen to 5556 port */

int main(void)
{
	int err, listen_sd;
	int sd, ret;
	struct sockaddr_in sa_serv;
	struct sockaddr_in sa_cli;
	socklen_t client_len;
	char topbuf[512];
	gnutls_session_t session;
	gnutls_srp_server_credentials_t srp_cred;
	gnutls_certificate_credentials_t cert_cred;
	char buffer[MAX_BUF + 1];
	int optval = 1;
	char name[256];

	strcpy(name, &quot;Echo Server&quot;);

	if (gnutls_check_version(&quot;3.1.4&quot;) == NULL) {
		fprintf(stderr,
			&quot;GnuTLS 3.1.4 or later is required for this example\n&quot;);
		exit(1);
	}

	/* for backwards compatibility with gnutls &lt; 3.3.0 */
	gnutls_global_init();

	/* SRP_PASSWD a password file (created with the included srptool utility) 
	 */
	gnutls_srp_allocate_server_credentials(&amp;srp_cred);
	gnutls_srp_set_server_credentials_file(srp_cred, SRP_PASSWD,
					       SRP_PASSWD_CONF);

	gnutls_certificate_allocate_credentials(&amp;cert_cred);
	gnutls_certificate_set_x509_trust_file(cert_cred, CAFILE,
					       GNUTLS_X509_FMT_PEM);
	gnutls_certificate_set_x509_key_file(cert_cred, CERTFILE, KEYFILE,
					     GNUTLS_X509_FMT_PEM);

	/* TCP socket operations
	 */
	listen_sd = socket(AF_INET, SOCK_STREAM, 0);
	SOCKET_ERR(listen_sd, &quot;socket&quot;);

	memset(&amp;sa_serv, '\0', sizeof(sa_serv));
	sa_serv.sin_family = AF_INET;
	sa_serv.sin_addr.s_addr = INADDR_ANY;
	sa_serv.sin_port = htons(PORT); /* Server Port number */

	setsockopt(listen_sd, SOL_SOCKET, SO_REUSEADDR, (void *)&amp;optval,
		   sizeof(int));

	err = bind(listen_sd, (struct sockaddr *)&amp;sa_serv, sizeof(sa_serv));
	SOCKET_ERR(err, &quot;bind&quot;);
	err = listen(listen_sd, 1024);
	SOCKET_ERR(err, &quot;listen&quot;);

	printf(&quot;%s ready. Listening to port '%d'.\n\n&quot;, name, PORT);

	client_len = sizeof(sa_cli);
	for (;;) {
		gnutls_init(&amp;session, GNUTLS_SERVER);
		gnutls_priority_set_direct(session,
					   &quot;NORMAL&quot;
					   &quot;:-KX-ALL:+SRP:+SRP-DSS:+SRP-RSA&quot;,
					   NULL);
		gnutls_credentials_set(session, GNUTLS_CRD_SRP, srp_cred);
		/* for the certificate authenticated ciphersuites.
		 */
		gnutls_credentials_set(session, GNUTLS_CRD_CERTIFICATE,
				       cert_cred);

		/* We don't request any certificate from the client.
		 * If we did we would need to verify it. One way of
		 * doing that is shown in the &quot;Verifying a certificate&quot;
		 * example.
		 */
		gnutls_certificate_server_set_request(session,
						      GNUTLS_CERT_IGNORE);

		sd = accept(listen_sd, (struct sockaddr *)&amp;sa_cli, &amp;client_len);

		printf(&quot;- connection from %s, port %d\n&quot;,
		       inet_ntop(AF_INET, &amp;sa_cli.sin_addr, topbuf,
				 sizeof(topbuf)),
		       ntohs(sa_cli.sin_port));

		gnutls_transport_set_int(session, sd);

		LOOP_CHECK(ret, gnutls_handshake(session));
		if (ret &lt; 0) {
			close(sd);
			gnutls_deinit(session);
			fprintf(stderr, &quot;*** Handshake has failed (%s)\n\n&quot;,
				gnutls_strerror(ret));
			continue;
		}
		printf(&quot;- Handshake was completed\n&quot;);
		printf(&quot;- User %s was connected\n&quot;,
		       gnutls_srp_server_get_username(session));

		/* print_info(session); */

		for (;;) {
			LOOP_CHECK(ret, gnutls_record_recv(session, buffer,
							   MAX_BUF));

			if (ret == 0) {
				printf(&quot;\n- Peer has closed the GnuTLS connection\n&quot;);
				break;
			} else if (ret &lt; 0 &amp;&amp; gnutls_error_is_fatal(ret) == 0) {
				fprintf(stderr, &quot;*** Warning: %s\n&quot;,
					gnutls_strerror(ret));
			} else if (ret &lt; 0) {
				fprintf(stderr,
					&quot;\n*** Received corrupted &quot;
					&quot;data(%d). Closing the connection.\n\n&quot;,
					ret);
				break;
			} else if (ret &gt; 0) {
				/* echo data back to the client
				 */
				gnutls_record_send(session, buffer, ret);
			}
		}
		printf(&quot;\n&quot;);
		/* do not wait for the peer to close the connection. */
		LOOP_CHECK(ret, gnutls_bye(session, GNUTLS_SHUT_WR));

		close(sd);
		gnutls_deinit(session);
	}
	close(listen_sd);

	gnutls_srp_free_server_credentials(srp_cred);
	gnutls_certificate_free_credentials(cert_cred);

	gnutls_global_deinit();

	return 0;
}
</pre>

<hr>
</div>
<div class="subsection-level-extent" id="Echo-server-with-anonymous-authentication">
<div class="nav-panel">
<p>
Next: <a href="#Helper-functions-for-TCP-connections" accesskey="n" rel="next">Helper functions for TCP connections</a>, Previous: <a href="#Echo-server-with-SRP-authentication" accesskey="p" rel="prev">Echo server with <abbr class="acronym">SRP</abbr> authentication</a>, Up: <a href="#More-advanced-client-and-servers" accesskey="u" rel="up">More advanced client and servers</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Echo-server-with-anonymous-authentication-1"><span>7.3.11 Echo server with anonymous authentication<a class="copiable-link" href="#Echo-server-with-anonymous-authentication-1"> &para;</a></span></h4>

<p>This example server supports anonymous authentication, and could be
used to serve the example client for anonymous authentication.
</p>
<pre class="verbatim">/* This example code is placed in the public domain. */

#ifdef HAVE_CONFIG_H
#include &lt;config.h&gt;
#endif

#include &lt;stdio.h&gt;
#include &lt;stdlib.h&gt;
#include &lt;errno.h&gt;
#include &lt;sys/types.h&gt;
#include &lt;sys/socket.h&gt;
#include &lt;arpa/inet.h&gt;
#include &lt;netinet/in.h&gt;
#include &lt;string.h&gt;
#include &lt;unistd.h&gt;
#include &lt;gnutls/gnutls.h&gt;

/* This is a sample TLS 1.0 echo server, for anonymous authentication only.
 */

#define SOCKET_ERR(err, s)  \
	if (err == -1) {    \
		perror(s);  \
		return (1); \
	}
#define MAX_BUF 1024
#define PORT 5556 /* listen to 5556 port */

int main(void)
{
	int err, listen_sd;
	int sd, ret;
	struct sockaddr_in sa_serv;
	struct sockaddr_in sa_cli;
	socklen_t client_len;
	char topbuf[512];
	gnutls_session_t session;
	gnutls_anon_server_credentials_t anoncred;
	char buffer[MAX_BUF + 1];
	int optval = 1;

	if (gnutls_check_version(&quot;3.1.4&quot;) == NULL) {
		fprintf(stderr,
			&quot;GnuTLS 3.1.4 or later is required for this example\n&quot;);
		exit(1);
	}

	/* for backwards compatibility with gnutls &lt; 3.3.0 */
	gnutls_global_init();

	gnutls_anon_allocate_server_credentials(&amp;anoncred);

	gnutls_anon_set_server_known_dh_params(anoncred,
					       GNUTLS_SEC_PARAM_MEDIUM);

	/* Socket operations
	 */
	listen_sd = socket(AF_INET, SOCK_STREAM, 0);
	SOCKET_ERR(listen_sd, &quot;socket&quot;);

	memset(&amp;sa_serv, '\0', sizeof(sa_serv));
	sa_serv.sin_family = AF_INET;
	sa_serv.sin_addr.s_addr = INADDR_ANY;
	sa_serv.sin_port = htons(PORT); /* Server Port number */

	setsockopt(listen_sd, SOL_SOCKET, SO_REUSEADDR, (void *)&amp;optval,
		   sizeof(int));

	err = bind(listen_sd, (struct sockaddr *)&amp;sa_serv, sizeof(sa_serv));
	SOCKET_ERR(err, &quot;bind&quot;);
	err = listen(listen_sd, 1024);
	SOCKET_ERR(err, &quot;listen&quot;);

	printf(&quot;Server ready. Listening to port '%d'.\n\n&quot;, PORT);

	client_len = sizeof(sa_cli);
	for (;;) {
		gnutls_init(&amp;session, GNUTLS_SERVER);
		gnutls_priority_set_direct(session,
					   &quot;NORMAL:+ANON-ECDH:+ANON-DH&quot;, NULL);
		gnutls_credentials_set(session, GNUTLS_CRD_ANON, anoncred);

		sd = accept(listen_sd, (struct sockaddr *)&amp;sa_cli, &amp;client_len);

		printf(&quot;- connection from %s, port %d\n&quot;,
		       inet_ntop(AF_INET, &amp;sa_cli.sin_addr, topbuf,
				 sizeof(topbuf)),
		       ntohs(sa_cli.sin_port));

		gnutls_transport_set_int(session, sd);

		do {
			ret = gnutls_handshake(session);
		} while (ret &lt; 0 &amp;&amp; gnutls_error_is_fatal(ret) == 0);

		if (ret &lt; 0) {
			close(sd);
			gnutls_deinit(session);
			fprintf(stderr, &quot;*** Handshake has failed (%s)\n\n&quot;,
				gnutls_strerror(ret));
			continue;
		}
		printf(&quot;- Handshake was completed\n&quot;);

		/* see the Getting peer's information example */
		/* print_info(session); */

		for (;;) {
			ret = gnutls_record_recv(session, buffer, MAX_BUF);

			if (ret == 0) {
				printf(&quot;\n- Peer has closed the GnuTLS connection\n&quot;);
				break;
			} else if (ret &lt; 0 &amp;&amp; gnutls_error_is_fatal(ret) == 0) {
				fprintf(stderr, &quot;*** Warning: %s\n&quot;,
					gnutls_strerror(ret));
			} else if (ret &lt; 0) {
				fprintf(stderr,
					&quot;\n*** Received corrupted &quot;
					&quot;data(%d). Closing the connection.\n\n&quot;,
					ret);
				break;
			} else if (ret &gt; 0) {
				/* echo data back to the client
				 */
				gnutls_record_send(session, buffer, ret);
			}
		}
		printf(&quot;\n&quot;);
		/* do not wait for the peer to close the connection.
		 */
		gnutls_bye(session, GNUTLS_SHUT_WR);

		close(sd);
		gnutls_deinit(session);
	}
	close(listen_sd);

	gnutls_anon_free_server_credentials(anoncred);

	gnutls_global_deinit();

	return 0;
}
</pre>


<hr>
</div>
<div class="subsection-level-extent" id="Helper-functions-for-TCP-connections">
<div class="nav-panel">
<p>
Next: <a href="#Helper-functions-for-UDP-connections" accesskey="n" rel="next">Helper functions for UDP connections</a>, Previous: <a href="#Echo-server-with-anonymous-authentication" accesskey="p" rel="prev">Echo server with anonymous authentication</a>, Up: <a href="#More-advanced-client-and-servers" accesskey="u" rel="up">More advanced client and servers</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Helper-functions-for-TCP-connections-1"><span>7.3.12 Helper functions for TCP connections<a class="copiable-link" href="#Helper-functions-for-TCP-connections-1"> &para;</a></span></h4>

<p>Those helper function abstract away TCP connection handling from the
other examples.  It is required to build some examples.
</p>
<pre class="verbatim">/* This example code is placed in the public domain. */

#ifdef HAVE_CONFIG_H
#include &lt;config.h&gt;
#endif

#include &lt;stdio.h&gt;
#include &lt;stdlib.h&gt;
#include &lt;string.h&gt;
#include &lt;sys/types.h&gt;
#include &lt;sys/socket.h&gt;
#include &lt;arpa/inet.h&gt;
#include &lt;netinet/in.h&gt;
#include &lt;unistd.h&gt;

/* tcp.c */
int tcp_connect(void);
void tcp_close(int sd);

/* Connects to the peer and returns a socket
 * descriptor.
 */
extern int tcp_connect(void)
{
	const char *PORT = &quot;5556&quot;;
	const char *SERVER = &quot;127.0.0.1&quot;;
	int err, sd;
	struct sockaddr_in sa;

	/* connects to server
	 */
	sd = socket(AF_INET, SOCK_STREAM, 0);

	memset(&amp;sa, '\0', sizeof(sa));
	sa.sin_family = AF_INET;
	sa.sin_port = htons(atoi(PORT));
	inet_pton(AF_INET, SERVER, &amp;sa.sin_addr);

	err = connect(sd, (struct sockaddr *)&amp;sa, sizeof(sa));
	if (err &lt; 0) {
		fprintf(stderr, &quot;Connect error\n&quot;);
		exit(1);
	}

	return sd;
}

/* closes the given socket descriptor.
 */
extern void tcp_close(int sd)
{
	shutdown(sd, SHUT_RDWR); /* no more receptions */
	close(sd);
}
</pre>
<hr>
</div>
<div class="subsection-level-extent" id="Helper-functions-for-UDP-connections">
<div class="nav-panel">
<p>
Previous: <a href="#Helper-functions-for-TCP-connections" accesskey="p" rel="prev">Helper functions for TCP connections</a>, Up: <a href="#More-advanced-client-and-servers" accesskey="u" rel="up">More advanced client and servers</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Helper-functions-for-UDP-connections-1"><span>7.3.13 Helper functions for UDP connections<a class="copiable-link" href="#Helper-functions-for-UDP-connections-1"> &para;</a></span></h4>

<p>The UDP helper functions abstract away UDP connection handling from the
other examples.  It is required to build the examples using UDP.
</p>
<pre class="verbatim">/* This example code is placed in the public domain. */

#ifdef HAVE_CONFIG_H
#include &lt;config.h&gt;
#endif

#include &lt;stdio.h&gt;
#include &lt;stdlib.h&gt;
#include &lt;string.h&gt;
#include &lt;sys/types.h&gt;
#include &lt;sys/socket.h&gt;
#include &lt;arpa/inet.h&gt;
#include &lt;netinet/in.h&gt;
#include &lt;unistd.h&gt;

/* udp.c */
int udp_connect(void);
void udp_close(int sd);

/* Connects to the peer and returns a socket
 * descriptor.
 */
extern int udp_connect(void)
{
	const char *PORT = &quot;5557&quot;;
	const char *SERVER = &quot;127.0.0.1&quot;;
	int err, sd;
#if defined(IP_DONTFRAG) || defined(IP_MTU_DISCOVER)
	int optval;
#endif
	struct sockaddr_in sa;

	/* connects to server
	 */
	sd = socket(AF_INET, SOCK_DGRAM, 0);

	memset(&amp;sa, '\0', sizeof(sa));
	sa.sin_family = AF_INET;
	sa.sin_port = htons(atoi(PORT));
	inet_pton(AF_INET, SERVER, &amp;sa.sin_addr);

#if defined(IP_DONTFRAG)
	optval = 1;
	setsockopt(sd, IPPROTO_IP, IP_DONTFRAG, (const void *)&amp;optval,
		   sizeof(optval));
#elif defined(IP_MTU_DISCOVER)
	optval = IP_PMTUDISC_DO;
	setsockopt(sd, IPPROTO_IP, IP_MTU_DISCOVER, (const void *)&amp;optval,
		   sizeof(optval));
#endif

	err = connect(sd, (struct sockaddr *)&amp;sa, sizeof(sa));
	if (err &lt; 0) {
		fprintf(stderr, &quot;Connect error\n&quot;);
		exit(1);
	}

	return sd;
}

/* closes the given socket descriptor.
 */
extern void udp_close(int sd)
{
	close(sd);
}
</pre>


<hr>
</div>
</div>
<div class="section-level-extent" id="OCSP-example">
<div class="nav-panel">
<p>
Next: <a href="#Miscellaneous-examples" accesskey="n" rel="next">Miscellaneous examples</a>, Previous: <a href="#More-advanced-client-and-servers" accesskey="p" rel="prev">More advanced client and servers</a>, Up: <a href="#GnuTLS-application-examples" accesskey="u" rel="up">GnuTLS application examples</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="OCSP-example-1"><span>7.4 OCSP example<a class="copiable-link" href="#OCSP-example-1"> &para;</a></span></h3>

<a class="anchor" id="Generate-OCSP-request"></a><h4 class="subheading" id="Generate-OCSP-request-1"><span>Generate <abbr class="acronym">OCSP</abbr> request<a class="copiable-link" href="#Generate-OCSP-request-1"> &para;</a></span></h4>

<p>A small tool to generate OCSP requests.
</p>
<pre class="verbatim">/* This example code is placed in the public domain. */

#ifdef HAVE_CONFIG_H
#include &lt;config.h&gt;
#endif

#include &lt;stdio.h&gt;
#include &lt;stdlib.h&gt;
#include &lt;string.h&gt;
#include &lt;gnutls/gnutls.h&gt;
#include &lt;gnutls/crypto.h&gt;
#include &lt;gnutls/ocsp.h&gt;
#ifndef NO_LIBCURL
#include &lt;curl/curl.h&gt;
#endif
#include &quot;read-file.h&quot;

size_t get_data(void *buffer, size_t size, size_t nmemb, void *userp);
static gnutls_x509_crt_t load_cert(const char *cert_file);
static void _response_info(const gnutls_datum_t *data);
static void _generate_request(gnutls_datum_t *rdata, gnutls_x509_crt_t cert,
			      gnutls_x509_crt_t issuer, gnutls_datum_t *nonce);
static int _verify_response(gnutls_datum_t *data, gnutls_x509_crt_t cert,
			    gnutls_x509_crt_t signer, gnutls_datum_t *nonce);

/* This program queries an OCSP server.
   It expects three files. argv[1] containing the certificate to
   be checked, argv[2] holding the issuer for this certificate,
   and argv[3] holding a trusted certificate to verify OCSP's response.
   argv[4] is optional and should hold the server host name.

   For simplicity the libcurl library is used.
 */

int main(int argc, char *argv[])
{
	gnutls_datum_t ud, tmp;
	int ret;
	gnutls_datum_t req;
	gnutls_x509_crt_t cert, issuer, signer;
#ifndef NO_LIBCURL
	CURL *handle;
	struct curl_slist *headers = NULL;
#endif
	int v, seq;
	const char *cert_file = argv[1];
	const char *issuer_file = argv[2];
	const char *signer_file = argv[3];
	char *hostname = NULL;
	unsigned char noncebuf[23];
	gnutls_datum_t nonce = { noncebuf, sizeof(noncebuf) };

	gnutls_global_init();

	if (argc &gt; 4)
		hostname = argv[4];

	ret = gnutls_rnd(GNUTLS_RND_NONCE, nonce.data, nonce.size);
	if (ret &lt; 0)
		exit(1);

	cert = load_cert(cert_file);
	issuer = load_cert(issuer_file);
	signer = load_cert(signer_file);

	if (hostname == NULL) {
		for (seq = 0;; seq++) {
			ret = gnutls_x509_crt_get_authority_info_access(
				cert, seq, GNUTLS_IA_OCSP_URI, &amp;tmp, NULL);
			if (ret == GNUTLS_E_UNKNOWN_ALGORITHM)
				continue;
			if (ret == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE) {
				fprintf(stderr,
					&quot;No URI was found in the certificate.\n&quot;);
				exit(1);
			}
			if (ret &lt; 0) {
				fprintf(stderr, &quot;error: %s\n&quot;,
					gnutls_strerror(ret));
				exit(1);
			}

			printf(&quot;CA issuers URI: %.*s\n&quot;, tmp.size, tmp.data);

			hostname = malloc(tmp.size + 1);
			if (!hostname) {
				fprintf(stderr,
					&quot;error: cannot allocate memory\n&quot;);
				exit(1);
			}
			memcpy(hostname, tmp.data, tmp.size);
			hostname[tmp.size] = 0;

			gnutls_free(tmp.data);
			break;
		}
	}

	/* Note that the OCSP servers hostname might be available
	 * using gnutls_x509_crt_get_authority_info_access() in the issuer's
	 * certificate */

	memset(&amp;ud, 0, sizeof(ud));
	fprintf(stderr, &quot;Connecting to %s\n&quot;, hostname);

	_generate_request(&amp;req, cert, issuer, &amp;nonce);

#ifndef NO_LIBCURL
	curl_global_init(CURL_GLOBAL_ALL);

	handle = curl_easy_init();
	if (handle == NULL)
		exit(1);

	headers = curl_slist_append(headers,
				    &quot;Content-Type: application/ocsp-request&quot;);

	curl_easy_setopt(handle, CURLOPT_HTTPHEADER, headers);
	curl_easy_setopt(handle, CURLOPT_POSTFIELDS, (void *)req.data);
	curl_easy_setopt(handle, CURLOPT_POSTFIELDSIZE, req.size);
	curl_easy_setopt(handle, CURLOPT_URL, hostname);
	curl_easy_setopt(handle, CURLOPT_WRITEFUNCTION, get_data);
	curl_easy_setopt(handle, CURLOPT_WRITEDATA, &amp;ud);

	ret = curl_easy_perform(handle);
	if (ret != 0) {
		fprintf(stderr, &quot;curl[%d] error %d\n&quot;, __LINE__, ret);
		exit(1);
	}

	curl_easy_cleanup(handle);
#endif

	_response_info(&amp;ud);

	v = _verify_response(&amp;ud, cert, signer, &amp;nonce);

	gnutls_x509_crt_deinit(cert);
	gnutls_x509_crt_deinit(issuer);
	gnutls_x509_crt_deinit(signer);
	gnutls_global_deinit();

	return v;
}

static void _response_info(const gnutls_datum_t *data)
{
	gnutls_ocsp_resp_t resp;
	int ret;
	gnutls_datum buf;

	ret = gnutls_ocsp_resp_init(&amp;resp);
	if (ret &lt; 0)
		exit(1);

	ret = gnutls_ocsp_resp_import(resp, data);
	if (ret &lt; 0)
		exit(1);

	ret = gnutls_ocsp_resp_print(resp, GNUTLS_OCSP_PRINT_FULL, &amp;buf);
	if (ret != 0)
		exit(1);

	printf(&quot;%.*s&quot;, buf.size, buf.data);
	gnutls_free(buf.data);

	gnutls_ocsp_resp_deinit(resp);
}

static gnutls_x509_crt_t load_cert(const char *cert_file)
{
	gnutls_x509_crt_t crt;
	int ret;
	gnutls_datum_t data;
	size_t size;

	ret = gnutls_x509_crt_init(&amp;crt);
	if (ret &lt; 0)
		exit(1);

	data.data = (void *)read_file(cert_file, RF_BINARY, &amp;size);
	data.size = size;

	if (!data.data) {
		fprintf(stderr, &quot;Cannot open file: %s\n&quot;, cert_file);
		exit(1);
	}

	ret = gnutls_x509_crt_import(crt, &amp;data, GNUTLS_X509_FMT_PEM);
	free(data.data);
	if (ret &lt; 0) {
		fprintf(stderr, &quot;Cannot import certificate in %s: %s\n&quot;,
			cert_file, gnutls_strerror(ret));
		exit(1);
	}

	return crt;
}

static void _generate_request(gnutls_datum_t *rdata, gnutls_x509_crt_t cert,
			      gnutls_x509_crt_t issuer, gnutls_datum_t *nonce)
{
	gnutls_ocsp_req_t req;
	int ret;

	ret = gnutls_ocsp_req_init(&amp;req);
	if (ret &lt; 0)
		exit(1);

	ret = gnutls_ocsp_req_add_cert(req, GNUTLS_DIG_SHA1, issuer, cert);
	if (ret &lt; 0)
		exit(1);

	ret = gnutls_ocsp_req_set_nonce(req, 0, nonce);
	if (ret &lt; 0)
		exit(1);

	ret = gnutls_ocsp_req_export(req, rdata);
	if (ret != 0)
		exit(1);

	gnutls_ocsp_req_deinit(req);

	return;
}

static int _verify_response(gnutls_datum_t *data, gnutls_x509_crt_t cert,
			    gnutls_x509_crt_t signer, gnutls_datum_t *nonce)
{
	gnutls_ocsp_resp_t resp;
	int ret;
	unsigned verify, resp_indx;
	gnutls_datum_t rnonce;

	ret = gnutls_ocsp_resp_init(&amp;resp);
	if (ret &lt; 0)
		exit(1);

	ret = gnutls_ocsp_resp_import(resp, data);
	if (ret &lt; 0)
		exit(1);

	for (resp_indx = 0;; resp_indx++) {
		ret = gnutls_ocsp_resp_check_crt(resp, resp_indx, cert);
		if (ret == 0 || ret == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE)
			break;
	}
	if (ret &lt; 0)
		exit(1);

	ret = gnutls_ocsp_resp_get_nonce(resp, NULL, &amp;rnonce);
	if (ret &lt; 0)
		exit(1);

	if (rnonce.size != nonce-&gt;size ||
	    memcmp(nonce-&gt;data, rnonce.data, nonce-&gt;size) != 0) {
		exit(1);
	}

	ret = gnutls_ocsp_resp_verify_direct(resp, signer, &amp;verify, 0);
	if (ret &lt; 0)
		exit(1);

	printf(&quot;Verifying OCSP Response: &quot;);
	if (verify == 0)
		printf(&quot;Verification success!\n&quot;);
	else
		printf(&quot;Verification error!\n&quot;);

	if (verify &amp; GNUTLS_OCSP_VERIFY_SIGNER_NOT_FOUND)
		printf(&quot;Signer cert not found\n&quot;);

	if (verify &amp; GNUTLS_OCSP_VERIFY_SIGNER_KEYUSAGE_ERROR)
		printf(&quot;Signer cert keyusage error\n&quot;);

	if (verify &amp; GNUTLS_OCSP_VERIFY_UNTRUSTED_SIGNER)
		printf(&quot;Signer cert is not trusted\n&quot;);

	if (verify &amp; GNUTLS_OCSP_VERIFY_INSECURE_ALGORITHM)
		printf(&quot;Insecure algorithm\n&quot;);

	if (verify &amp; GNUTLS_OCSP_VERIFY_SIGNATURE_FAILURE)
		printf(&quot;Signature failure\n&quot;);

	if (verify &amp; GNUTLS_OCSP_VERIFY_CERT_NOT_ACTIVATED)
		printf(&quot;Signer cert not yet activated\n&quot;);

	if (verify &amp; GNUTLS_OCSP_VERIFY_CERT_EXPIRED)
		printf(&quot;Signer cert expired\n&quot;);

	gnutls_free(rnonce.data);
	gnutls_ocsp_resp_deinit(resp);

	return verify;
}

size_t get_data(void *buffer, size_t size, size_t nmemb, void *userp)
{
	gnutls_datum_t *ud = userp;

	size *= nmemb;

	ud-&gt;data = realloc(ud-&gt;data, size + ud-&gt;size);
	if (ud-&gt;data == NULL) {
		fprintf(stderr, &quot;Not enough memory for the request\n&quot;);
		exit(1);
	}

	memcpy(&amp;ud-&gt;data[ud-&gt;size], buffer, size);
	ud-&gt;size += size;

	return size;
}
</pre>
<hr>
</div>
<div class="section-level-extent" id="Miscellaneous-examples">
<div class="nav-panel">
<p>
Previous: <a href="#OCSP-example" accesskey="p" rel="prev">OCSP example</a>, Up: <a href="#GnuTLS-application-examples" accesskey="u" rel="up">GnuTLS application examples</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Miscellaneous-examples-1"><span>7.5 Miscellaneous examples<a class="copiable-link" href="#Miscellaneous-examples-1"> &para;</a></span></h3>


<ul class="mini-toc">
<li><a href="#Checking-for-an-alert" accesskey="1">Checking for an alert</a></li>
<li><a href="#X_002e509-certificate-parsing-example" accesskey="2"><abbr class="acronym">X.509</abbr> certificate parsing example</a></li>
<li><a href="#Listing-the-ciphersuites-in-a-priority-string" accesskey="3">Listing the ciphersuites in a priority string</a></li>
<li><a href="#PKCS12-structure-generation-example" accesskey="4">PKCS #12 structure generation example</a></li>
</ul>
<hr>
<div class="subsection-level-extent" id="Checking-for-an-alert">
<div class="nav-panel">
<p>
Next: <a href="#X_002e509-certificate-parsing-example" accesskey="n" rel="next"><abbr class="acronym">X.509</abbr> certificate parsing example</a>, Up: <a href="#Miscellaneous-examples" accesskey="u" rel="up">Miscellaneous examples</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Checking-for-an-alert-1"><span>7.5.1 Checking for an alert<a class="copiable-link" href="#Checking-for-an-alert-1"> &para;</a></span></h4>

<p>This is a function that checks if an alert has been received in the
current session.
</p>
<pre class="verbatim">/* This example code is placed in the public domain. */

#ifdef HAVE_CONFIG_H
#include &lt;config.h&gt;
#endif

#include &lt;stdio.h&gt;
#include &lt;stdlib.h&gt;
#include &lt;gnutls/gnutls.h&gt;

#include &quot;examples.h&quot;

/* This function will check whether the given return code from
 * a gnutls function (recv/send), is an alert, and will print
 * that alert.
 */
void check_alert(gnutls_session_t session, int ret)
{
	int last_alert;

	if (ret == GNUTLS_E_WARNING_ALERT_RECEIVED ||
	    ret == GNUTLS_E_FATAL_ALERT_RECEIVED) {
		last_alert = gnutls_alert_get(session);

		/* The check for renegotiation is only useful if we are 
		 * a server, and we had requested a rehandshake.
		 */
		if (last_alert == GNUTLS_A_NO_RENEGOTIATION &amp;&amp;
		    ret == GNUTLS_E_WARNING_ALERT_RECEIVED)
			printf(&quot;* Received NO_RENEGOTIATION alert. &quot;
			       &quot;Client Does not support renegotiation.\n&quot;);
		else
			printf(&quot;* Received alert '%d': %s.\n&quot;, last_alert,
			       gnutls_alert_get_name(last_alert));
	}
}
</pre>
<hr>
</div>
<div class="subsection-level-extent" id="X_002e509-certificate-parsing-example">
<div class="nav-panel">
<p>
Next: <a href="#Listing-the-ciphersuites-in-a-priority-string" accesskey="n" rel="next">Listing the ciphersuites in a priority string</a>, Previous: <a href="#Checking-for-an-alert" accesskey="p" rel="prev">Checking for an alert</a>, Up: <a href="#Miscellaneous-examples" accesskey="u" rel="up">Miscellaneous examples</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="X_002e509-certificate-parsing-example-1"><span>7.5.2 <abbr class="acronym">X.509</abbr> certificate parsing example<a class="copiable-link" href="#X_002e509-certificate-parsing-example-1"> &para;</a></span></h4>
<a class="anchor" id="ex_002dx509_002dinfo"></a>
<p>To demonstrate the <abbr class="acronym">X.509</abbr> parsing capabilities an example program is
listed below.  That program reads the peer&rsquo;s certificate, and prints
information about it.
</p>
<pre class="verbatim">/* This example code is placed in the public domain. */

#ifdef HAVE_CONFIG_H
#include &lt;config.h&gt;
#endif

#include &lt;stdio.h&gt;
#include &lt;stdlib.h&gt;
#include &lt;gnutls/gnutls.h&gt;
#include &lt;gnutls/x509.h&gt;

#include &quot;examples.h&quot;

static const char *bin2hex(const void *bin, size_t bin_size)
{
	static char printable[110];
	const unsigned char *_bin = bin;
	char *print;
	size_t i;

	if (bin_size &gt; 50)
		bin_size = 50;

	print = printable;
	for (i = 0; i &lt; bin_size; i++) {
		sprintf(print, &quot;%.2x &quot;, _bin[i]);
		print += 2;
	}

	return printable;
}

/* This function will print information about this session's peer
 * certificate.
 */
void print_x509_certificate_info(gnutls_session_t session)
{
	char serial[40];
	char dn[256];
	size_t size;
	unsigned int algo, bits;
	time_t expiration_time, activation_time;
	const gnutls_datum_t *cert_list;
	unsigned int cert_list_size = 0;
	gnutls_x509_crt_t cert;
	gnutls_datum_t cinfo;

	/* This function only works for X.509 certificates.
	 */
	if (gnutls_certificate_type_get(session) != GNUTLS_CRT_X509)
		return;

	cert_list = gnutls_certificate_get_peers(session, &amp;cert_list_size);

	printf(&quot;Peer provided %d certificates.\n&quot;, cert_list_size);

	if (cert_list_size &gt; 0) {
		int ret;

		/* we only print information about the first certificate.
		 */
		gnutls_x509_crt_init(&amp;cert);

		gnutls_x509_crt_import(cert, &amp;cert_list[0],
				       GNUTLS_X509_FMT_DER);

		printf(&quot;Certificate info:\n&quot;);

		/* This is the preferred way of printing short information about
		   a certificate. */

		ret = gnutls_x509_crt_print(cert, GNUTLS_CRT_PRINT_ONELINE,
					    &amp;cinfo);
		if (ret == 0) {
			printf(&quot;\t%s\n&quot;, cinfo.data);
			gnutls_free(cinfo.data);
		}

		/* If you want to extract fields manually for some other reason,
		   below are popular example calls. */

		expiration_time = gnutls_x509_crt_get_expiration_time(cert);
		activation_time = gnutls_x509_crt_get_activation_time(cert);

		printf(&quot;\tCertificate is valid since: %s&quot;,
		       ctime(&amp;activation_time));
		printf(&quot;\tCertificate expires: %s&quot;, ctime(&amp;expiration_time));

		/* Print the serial number of the certificate.
		 */
		size = sizeof(serial);
		gnutls_x509_crt_get_serial(cert, serial, &amp;size);

		printf(&quot;\tCertificate serial number: %s\n&quot;,
		       bin2hex(serial, size));

		/* Extract some of the public key algorithm's parameters
		 */
		algo = gnutls_x509_crt_get_pk_algorithm(cert, &amp;bits);

		printf(&quot;Certificate public key: %s&quot;,
		       gnutls_pk_algorithm_get_name(algo));

		/* Print the version of the X.509
		 * certificate.
		 */
		printf(&quot;\tCertificate version: #%d\n&quot;,
		       gnutls_x509_crt_get_version(cert));

		size = sizeof(dn);
		gnutls_x509_crt_get_dn(cert, dn, &amp;size);
		printf(&quot;\tDN: %s\n&quot;, dn);

		size = sizeof(dn);
		gnutls_x509_crt_get_issuer_dn(cert, dn, &amp;size);
		printf(&quot;\tIssuer's DN: %s\n&quot;, dn);

		gnutls_x509_crt_deinit(cert);
	}
}
</pre>
<hr>
</div>
<div class="subsection-level-extent" id="Listing-the-ciphersuites-in-a-priority-string">
<div class="nav-panel">
<p>
Next: <a href="#PKCS12-structure-generation-example" accesskey="n" rel="next">PKCS #12 structure generation example</a>, Previous: <a href="#X_002e509-certificate-parsing-example" accesskey="p" rel="prev"><abbr class="acronym">X.509</abbr> certificate parsing example</a>, Up: <a href="#Miscellaneous-examples" accesskey="u" rel="up">Miscellaneous examples</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Listing-the-ciphersuites-in-a-priority-string-1"><span>7.5.3 Listing the ciphersuites in a priority string<a class="copiable-link" href="#Listing-the-ciphersuites-in-a-priority-string-1"> &para;</a></span></h4>

<p>This is a small program to list the enabled ciphersuites by a 
priority string.
</p>
<pre class="verbatim">/* This example code is placed in the public domain. */

#include &lt;config.h&gt;
#include &lt;stdio.h&gt;
#include &lt;stdlib.h&gt;
#include &lt;string.h&gt;
#include &lt;gnutls/gnutls.h&gt;

static void print_cipher_suite_list(const char *priorities)
{
	size_t i;
	int ret;
	unsigned int idx;
	const char *name;
	const char *err;
	unsigned char id[2];
	gnutls_protocol_t version;
	gnutls_priority_t pcache;

	if (priorities != NULL) {
		printf(&quot;Cipher suites for %s\n&quot;, priorities);

		ret = gnutls_priority_init(&amp;pcache, priorities, &amp;err);
		if (ret &lt; 0) {
			fprintf(stderr, &quot;Syntax error at: %s\n&quot;, err);
			exit(1);
		}

		for (i = 0;; i++) {
			ret = gnutls_priority_get_cipher_suite_index(pcache, i,
								     &amp;idx);
			if (ret == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE)
				break;
			if (ret == GNUTLS_E_UNKNOWN_CIPHER_SUITE)
				continue;

			name = gnutls_cipher_suite_info(idx, id, NULL, NULL,
							NULL, &amp;version);

			if (name != NULL)
				printf(&quot;%-50s\t0x%02x, 0x%02x\t%s\n&quot;, name,
				       (unsigned char)id[0],
				       (unsigned char)id[1],
				       gnutls_protocol_get_name(version));
		}

		return;
	}
}

int main(int argc, char **argv)
{
	if (argc &gt; 1)
		print_cipher_suite_list(argv[1]);
	return 0;
}
</pre>
<hr>
</div>
<div class="subsection-level-extent" id="PKCS12-structure-generation-example">
<div class="nav-panel">
<p>
Previous: <a href="#Listing-the-ciphersuites-in-a-priority-string" accesskey="p" rel="prev">Listing the ciphersuites in a priority string</a>, Up: <a href="#Miscellaneous-examples" accesskey="u" rel="up">Miscellaneous examples</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="PKCS-_002312-structure-generation-example"><span>7.5.4 PKCS #12 structure generation example<a class="copiable-link" href="#PKCS-_002312-structure-generation-example"> &para;</a></span></h4>

<p>This small program demonstrates the usage of the PKCS #12 API, by generating
such a structure.
</p>
<pre class="verbatim">/* This example code is placed in the public domain. */

#ifdef HAVE_CONFIG_H
#include &lt;config.h&gt;
#endif

#include &lt;stdio.h&gt;
#include &lt;stdlib.h&gt;
#include &lt;gnutls/gnutls.h&gt;
#include &lt;gnutls/pkcs12.h&gt;

#include &quot;examples.h&quot;

#define OUTFILE &quot;out.p12&quot;

/* This function will write a pkcs12 structure into a file.
 * cert: is a DER encoded certificate
 * pkcs8_key: is a PKCS #8 encrypted key (note that this must be
 *  encrypted using a PKCS #12 cipher, or some browsers will crash)
 * password: is the password used to encrypt the PKCS #12 packet.
 */
int write_pkcs12(const gnutls_datum_t *cert, const gnutls_datum_t *pkcs8_key,
		 const char *password)
{
	gnutls_pkcs12_t pkcs12;
	int ret, bag_index;
	gnutls_pkcs12_bag_t bag, key_bag;
	char pkcs12_struct[10 * 1024];
	size_t pkcs12_struct_size;
	FILE *fp;

	/* A good idea might be to use gnutls_x509_privkey_get_key_id()
	 * to obtain a unique ID.
	 */
	gnutls_datum_t key_id = { (void *)&quot;\x00\x00\x07&quot;, 3 };

	gnutls_global_init();

	/* Firstly we create two helper bags, which hold the certificate,
	 * and the (encrypted) key.
	 */

	gnutls_pkcs12_bag_init(&amp;bag);
	gnutls_pkcs12_bag_init(&amp;key_bag);

	ret = gnutls_pkcs12_bag_set_data(bag, GNUTLS_BAG_CERTIFICATE, cert);
	if (ret &lt; 0) {
		fprintf(stderr, &quot;ret: %s\n&quot;, gnutls_strerror(ret));
		return 1;
	}

	/* ret now holds the bag's index.
	 */
	bag_index = ret;

	/* Associate a friendly name with the given certificate. Used
	 * by browsers.
	 */
	gnutls_pkcs12_bag_set_friendly_name(bag, bag_index, &quot;My name&quot;);

	/* Associate the certificate with the key using a unique key
	 * ID.
	 */
	gnutls_pkcs12_bag_set_key_id(bag, bag_index, &amp;key_id);

	/* use weak encryption for the certificate. 
	 */
	gnutls_pkcs12_bag_encrypt(bag, password, GNUTLS_PKCS_USE_PKCS12_RC2_40);

	/* Now the key.
	 */

	ret = gnutls_pkcs12_bag_set_data(
		key_bag, GNUTLS_BAG_PKCS8_ENCRYPTED_KEY, pkcs8_key);
	if (ret &lt; 0) {
		fprintf(stderr, &quot;ret: %s\n&quot;, gnutls_strerror(ret));
		return 1;
	}

	/* Note that since the PKCS #8 key is already encrypted we don't
	 * bother encrypting that bag.
	 */
	bag_index = ret;

	gnutls_pkcs12_bag_set_friendly_name(key_bag, bag_index, &quot;My name&quot;);

	gnutls_pkcs12_bag_set_key_id(key_bag, bag_index, &amp;key_id);

	/* The bags were filled. Now create the PKCS #12 structure.
	 */
	gnutls_pkcs12_init(&amp;pkcs12);

	/* Insert the two bags in the PKCS #12 structure.
	 */

	gnutls_pkcs12_set_bag(pkcs12, bag);
	gnutls_pkcs12_set_bag(pkcs12, key_bag);

	/* Generate a message authentication code for the PKCS #12
	 * structure.
	 */
	gnutls_pkcs12_generate_mac(pkcs12, password);

	pkcs12_struct_size = sizeof(pkcs12_struct);
	ret = gnutls_pkcs12_export(pkcs12, GNUTLS_X509_FMT_DER, pkcs12_struct,
				   &amp;pkcs12_struct_size);
	if (ret &lt; 0) {
		fprintf(stderr, &quot;ret: %s\n&quot;, gnutls_strerror(ret));
		return 1;
	}

	fp = fopen(OUTFILE, &quot;w&quot;);
	if (fp == NULL) {
		fprintf(stderr, &quot;cannot open file\n&quot;);
		return 1;
	}
	fwrite(pkcs12_struct, 1, pkcs12_struct_size, fp);
	fclose(fp);

	gnutls_pkcs12_bag_deinit(bag);
	gnutls_pkcs12_bag_deinit(key_bag);
	gnutls_pkcs12_deinit(pkcs12);

	return 0;
}
</pre>

<hr>
</div>
</div>
</div>
<div class="chapter-level-extent" id="System_002dwide-configuration-of-the-library">
<div class="nav-panel">
<p>
Next: <a href="#Using-GnuTLS-as-a-cryptographic-library" accesskey="n" rel="next">Using GnuTLS as a cryptographic library</a>, Previous: <a href="#GnuTLS-application-examples" accesskey="p" rel="prev">GnuTLS application examples</a>, Up: <a href="#Top" accesskey="u" rel="up">GnuTLS</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h2 class="chapter" id="System_002dwide-configuration-of-the-library-1"><span>8 System-wide configuration of the library<a class="copiable-link" href="#System_002dwide-configuration-of-the-library-1"> &para;</a></span></h2>
<a class="index-entry-id" id="index-System_002dwide-configuration"></a>

<p><abbr class="acronym">GnuTLS</abbr> 3.6.9 introduced a system-wide configuration of the library
which can be used to disable or mark algorithms and protocols as insecure
system-wide, overriding the library defaults. The format of this
configuration file is of an INI file, with the hash (&rsquo;#&rsquo;) allowed for
commenting. It intentionally does not allow switching algorithms or protocols
which were disabled or marked as insecure during compile time to the secure
set. This is to prevent the feature from being used to attack the system.
Unknown options or sections in the configuration file are skipped unless
the environment variable <code class="code">GNUTLS_SYSTEM_PRIORITY_FAIL_ON_INVALID</code> is
set to 1, where it would cause the library to exit on unknown options.
</p>
<p>The location of the default configuration file is <code class="code">/etc/gnutls/config</code>,
but its actual location may be overridden during compile time or at run-time
using the <code class="code">GNUTLS_SYSTEM_PRIORITY_FILE</code> environment variable. The file
used can be queried using <a class="ref" href="#gnutls_005fget_005fsystem_005fconfig_005ffile">gnutls_get_system_config_file</a>.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fget_005fsystem_005fconfig_005ffile"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_get_system_config_file</strong> <code class="def-code-arguments">( <var class="var">void</var>)</code><a class="copiable-link" href="#index-gnutls_005fget_005fsystem_005fconfig_005ffile"> &para;</a></span></dt>
<dd>
<p>Returns the filename of the system wide configuration
file to be loaded by the library.
</p>
<p><strong class="strong">Returns:</strong> a constant pointer to the config file path
</p>
<p><strong class="strong">Since:</strong> 3.6.9
</p></dd></dl>


<ul class="mini-toc">
<li><a href="#Application_002dspecific-priority-strings" accesskey="1">Application-specific priority strings</a></li>
<li><a href="#Disabling-algorithms-and-protocols" accesskey="2">Disabling algorithms and protocols</a></li>
<li><a href="#Querying-for-disabled-algorithms-and-protocols" accesskey="3">Querying for disabled algorithms and protocols</a></li>
<li><a href="#Overriding-the-parameter-verification-profile" accesskey="4">Overriding the parameter verification profile</a></li>
<li><a href="#Overriding-the-default-priority-string" accesskey="5">Overriding the default priority string</a></li>
<li><a href="#Enabling-TLS-certificate-compression" accesskey="6">Enabling TLS certificate compression</a></li>
<li><a href="#Enabling_002fDisabling-system_002facceleration-protocols" accesskey="7">Enabling/Disabling system/acceleration protocols</a></li>
<li><a href="#Enabling_002fDisabling-RSAES_002dPKCS1_002dv1_005f5" accesskey="8">Enabling/Disabling RSAES-PKCS1-v1_5</a></li>
<li><a href="#Using-PKCS_002311-module-as-cryptographic-backend" accesskey="9">Using PKCS#11 module as cryptographic backend</a></li>
</ul>
<hr>
<div class="section-level-extent" id="Application_002dspecific-priority-strings">
<div class="nav-panel">
<p>
Next: <a href="#Disabling-algorithms-and-protocols" accesskey="n" rel="next">Disabling algorithms and protocols</a>, Up: <a href="#System_002dwide-configuration-of-the-library" accesskey="u" rel="up">System-wide configuration of the library</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Application_002dspecific-priority-strings-1"><span>8.1 Application-specific priority strings<a class="copiable-link" href="#Application_002dspecific-priority-strings-1"> &para;</a></span></h3>

<p>It is possible to specify custom cipher priority strings, in addition to the
default priority strings (<code class="code">NORMAL</code>, <code class="code">PERFORMANCE</code>, etc.). These can
be used either by individual applications, or even as the default option if
the library is compiled with the configuration option
<code class="code">--with-default-priority-string</code>. In the latter case the defined
priority string will be used for applications using <a class="ref" href="#gnutls_005fset_005fdefault_005fpriority">gnutls_set_default_priority</a>
or <a class="ref" href="#gnutls_005fset_005fdefault_005fpriority_005fappend">gnutls_set_default_priority_append</a>.
</p>
<p>The priority strings can be specified in the global section of the
configuration file, or in the section named <code class="code">[priorities]</code>.
The format is &rsquo;<code class="code">KEYWORD = VALUE</code>&rsquo;, e.g.,
</p>
<p>When used they may be followed by additional options that will be appended to the
system string (e.g., &rsquo;<code class="code">@EXAMPLE-PRIORITY:+SRP</code>&rsquo;). &rsquo;<code class="code">EXAMPLE-PRIORITY=NORMAL:+ARCFOUR-128</code>&rsquo;.
Since version 3.5.1 it is allowed to specify fallback keywords by
separating them with a comma, such as @KEYWORD1,KEYWORD2, and the
first valid keyword will be used.
</p>
<p>The following example configuration defines a priority string called <code class="code">@SYSTEM</code>.
When set, its full settings can be queried using <code class="code">gnutls-cli --priority @SYSTEM --list</code>.
</p>
<div class="example">
<pre class="example-preformatted">[priorities]
SYSTEM = NORMAL:-AES-128-CBC:-AES-256-CBC
</pre></div>


<hr>
</div>
<div class="section-level-extent" id="Disabling-algorithms-and-protocols">
<div class="nav-panel">
<p>
Next: <a href="#Querying-for-disabled-algorithms-and-protocols" accesskey="n" rel="next">Querying for disabled algorithms and protocols</a>, Previous: <a href="#Application_002dspecific-priority-strings" accesskey="p" rel="prev">Application-specific priority strings</a>, Up: <a href="#System_002dwide-configuration-of-the-library" accesskey="u" rel="up">System-wide configuration of the library</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Disabling-algorithms-and-protocols-1"><span>8.2 Disabling algorithms and protocols<a class="copiable-link" href="#Disabling-algorithms-and-protocols-1"> &para;</a></span></h3>

<p>The approach above works well to create consistent system-wide settings
for cooperative GnuTLS applications. When an application however does not
use the <a class="ref" href="#gnutls_005fset_005fdefault_005fpriority">gnutls_set_default_priority</a> or <a class="ref" href="#gnutls_005fset_005fdefault_005fpriority_005fappend">gnutls_set_default_priority_append</a>
functions, the method is not sufficient to prevent applications from using
protocols or algorithms forbidden by a local policy.
The override method described below enables the deprecation of algorithms and
protocols system-wide for all applications.
</p>
<p>The available options must be set in the <code class="code">[overrides]</code> section of the
configuration file and can be
</p><ul class="itemize mark-bullet">
<li><code class="code">insecure-sig-for-cert</code>: to mark the signature algorithm as insecure when used in certificates.
</li><li><code class="code">insecure-sig</code>: to mark the signature algorithm as insecure for any use.
</li><li><code class="code">insecure-hash</code>: to mark the hash algorithm as insecure for digital signature use (provides a more generic way to disable digital signatures for broken hash algorithms).
</li><li><code class="code">disabled-curve</code>: to disable the specified elliptic curve.
</li><li><code class="code">disabled-version</code>: to disable the specified TLS versions.
</li><li><code class="code">tls-disabled-cipher</code>: to disable the specified ciphers for use in the TLS or DTLS protocols.
</li><li><code class="code">tls-disabled-mac</code>: to disable the specified MAC algorithms for use in the TLS or DTLS protocols.
</li><li><code class="code">tls-disabled-group</code>: to disable the specified group for use in the TLS or DTLS protocols.
</li><li><code class="code">tls-disabled-kx</code>: to disable the specified key exchange algorithms for use in the TLS or DTLS protocols (applies to TLS1.2 or earlier).
</li></ul>

<p>Each of the options can be repeated multiple times when multiple values need
to be disabled or enabled.
</p>
<p>The valid values for the options above can be found in the &rsquo;Protocols&rsquo;, &rsquo;Digests&rsquo;
&rsquo;PK-signatures&rsquo;, &rsquo;Protocols&rsquo;, &rsquo;Ciphers&rsquo;, and &rsquo;MACs&rsquo; fields of the output of <code class="code">gnutls-cli --list</code>.
</p>
<p>Sometimes the system administrator wants to enable only specific
algorithms, despite the library defaults. GnuTLS provides an
alternative mode of overriding: allowlisting.
</p>
<p>As shown below in the examples, it is hard to use this mode correctly,
as it requires understanding of how algorithms are used underneath by
the protocols.  Allowlisting configuration mode is intended to be used
by the operating system vendors that prefer laying out the library
defaults exhaustively from scratch instead on depending on gnutls
presets, such as <code class="code">NORMAL</code>.  Applications are then expected to
optionally disable or enable only a subset algorithms on top of the
vendor-provided configuration.
</p>
<p>In the allowlisting mode, all the algorithms are initially marked as
insecure or disabled, and shall be explicitly turned on by the options
listed below in the <code class="code">[overrides]</code> section.  As the allowlisting
mode is mutually exclusive to the blocklisting mode, the options
listed above for the blocklisting mode are forbidden in the
allowlisting mode, and vice versa.
</p>
<ul class="itemize mark-bullet">
<li><code class="code">secure-sig-for-cert</code>: to mark the signature algorithm as secure when used in certificates.
</li><li><code class="code">secure-sig</code>: to mark the signature algorithm as secure for any use.
</li><li><code class="code">secure-hash</code>: to mark the hash algorithm as secure for digital signature use (provides a more generic way to enable digital signatures for broken hash algorithms).
</li><li><code class="code">enabled-curve</code>: to enable the specified elliptic curve.
</li><li><code class="code">enabled-version</code>: to enable the specified TLS versions.
</li><li><code class="code">tls-enabled-cipher</code>: to enable the specified ciphers for use in the TLS or DTLS protocols.
</li><li><code class="code">tls-enabled-mac</code>: to enable the specified MAC algorithms for use in the TLS or DTLS protocols.
</li><li><code class="code">tls-enabled-group</code>: to enable the specified group for use in the TLS or DTLS protocols.
</li><li><code class="code">tls-enabled-kx</code>: to enable the specified key exchange algorithms for use in the TLS or DTLS protocols (applies to TLS1.2 or earlier).
</li></ul>

<p>The allowlisting mode can be enabled by adding <code class="code">override-mode =
allowlist</code> in the <code class="code">[global]</code> section.
</p>
<p>The following functions allow the applications to modify the setting.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fecc_005fcurve_005fset_005fenabled">gnutls_ecc_curve_set_enabled</a> (gnutls_ecc_curve_t <var class="var">curve</var>, unsigned int <var class="var">enabled</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fsign_005fset_005fsecure">gnutls_sign_set_secure</a> (gnutls_sign_algorithm_t <var class="var">sign</var>, unsigned int <var class="var">secure</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fsign_005fset_005fsecure_005ffor_005fcerts">gnutls_sign_set_secure_for_certs</a> (gnutls_sign_algorithm_t <var class="var">sign</var>, unsigned int <var class="var">secure</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fdigest_005fset_005fsecure">gnutls_digest_set_secure</a> (gnutls_digest_algorithm_t <var class="var">dig</var>, unsigned int <var class="var">secure</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fprotocol_005fset_005fenabled">gnutls_protocol_set_enabled</a> (gnutls_protocol_t <var class="var">version</var>, unsigned int <var class="var">enabled</var>)</code></dt>
</dl>

<p>When the allowlisting mode is in effect, a <code class="code">@SYSTEM</code> priority
string is automatically constructed from the options in the
<code class="code">[overrides]</code> section.  For this reason, the above functions
should be called before the <code class="code">@SYSTEM</code> priority is used.
</p>
<ul class="mini-toc">
<li><a href="#Examples" accesskey="1">Examples</a></li>
</ul>
<div class="subsection-level-extent" id="Examples">
<h4 class="subsection"><span>8.2.1 Examples<a class="copiable-link" href="#Examples"> &para;</a></span></h4>

<p>The following example marks as insecure all digital signature algorithms
which depend on SHA384, as well as the RSA-SHA1 signature algorithm.
</p>
<div class="example">
<pre class="example-preformatted">[overrides]
insecure-hash = sha384
insecure-sig = rsa-sha1
</pre></div>

<p>The following example marks RSA-SHA256 as insecure for use in certificates
and disables the TLS1.0 and TLS1.1 protocols.
</p>
<div class="example">
<pre class="example-preformatted">[overrides]
insecure-sig-for-cert = rsa-sha256
disabled-version = tls1.0
disabled-version = tls1.1
</pre></div>

<p>The following example disables the <code class="code">AES-128-CBC</code> and <code class="code">AES-256-CBC</code>
ciphers, the <code class="code">HMAC-SHA1</code> MAC algorithm and the <code class="code">GROUP-FFDHE8192</code>
group for TLS and DTLS protocols.
</p>
<div class="example">
<pre class="example-preformatted">[overrides]
tls-disabled-cipher = aes-128-cbc
tls-disabled-cipher = aes-256-cbc
tls-disabled-mac = sha1
tls-disabled-group = group-ffdhe8192
</pre></div>

<p>The following example demonstrates the use of the allowlisting
mode. All the signature algorithms are disabled by default but
<code class="code">RSA-SHA256</code>. Note that the hash algorithm <code class="code">SHA256</code> also
needs to be explicitly enabled.
</p>
<div class="example">
<pre class="example-preformatted">[global]
override-mode = allowlist

[overrides]
secure-hash = sha256
secure-sig = rsa-sha256
</pre></div>

<p>To enable a TLS ciphersuite in the allowlist mode requires a more
verbose configuration, explicitly listing algorithm dependencies.  The
following example enables TLS_AES_128_GCM_SHA256, using the SECP256R1
curve for signing and key exchange.
</p>
<div class="example">
<pre class="example-preformatted">[global]
override-mode = allowlist

[overrides]
secure-hash = sha256
enabled-curve = secp256r1
secure-sig = ecdsa-secp256r1-sha256
enabled-version = tls1.3
tls-enabled-cipher = aes-128-gcm
tls-enabled-mac = aead
tls-enabled-group = secp256r1
</pre></div>

<hr>
</div>
</div>
<div class="section-level-extent" id="Querying-for-disabled-algorithms-and-protocols">
<div class="nav-panel">
<p>
Next: <a href="#Overriding-the-parameter-verification-profile" accesskey="n" rel="next">Overriding the parameter verification profile</a>, Previous: <a href="#Disabling-algorithms-and-protocols" accesskey="p" rel="prev">Disabling algorithms and protocols</a>, Up: <a href="#System_002dwide-configuration-of-the-library" accesskey="u" rel="up">System-wide configuration of the library</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Querying-for-disabled-algorithms-and-protocols-1"><span>8.3 Querying for disabled algorithms and protocols<a class="copiable-link" href="#Querying-for-disabled-algorithms-and-protocols-1"> &para;</a></span></h3>

<p>When necessary applications can query whether a particular algorithm
or protocol has been marked as insecure or disabled system-wide.
Digital signatures can be queried using the following algorithms.
</p><dl class="table">
<dt><code class="code"><var class="var">unsigned</var> <a class="ref" href="#gnutls_005fsign_005fis_005fsecure">gnutls_sign_is_secure</a> (gnutls_sign_algorithm_t <var class="var">algorithm</var>)</code></dt>
<dt><code class="code"><var class="var">unsigned</var> <a class="ref" href="#gnutls_005fsign_005fis_005fsecure2">gnutls_sign_is_secure2</a> (gnutls_sign_algorithm_t <var class="var">algorithm</var>, unsigned int <var class="var">flags</var>)</code></dt>
</dl>

<p>Any disabled protocol versions or elliptic curves will not show up in the
lists provided by the following functions.
</p>
<dl class="table">
<dt><code class="code"><var class="var">const gnutls_protocol_t *</var> <a class="ref" href="#gnutls_005fprotocol_005flist">gnutls_protocol_list</a> ( <var class="var">void</var>)</code></dt>
<dt><code class="code"><var class="var">const gnutls_group_t *</var> <a class="ref" href="#gnutls_005fgroup_005flist">gnutls_group_list</a> ( <var class="var">void</var>)</code></dt>
<dt><code class="code"><var class="var">const gnutls_ecc_curve_t *</var> <a class="ref" href="#gnutls_005fecc_005fcurve_005flist">gnutls_ecc_curve_list</a> ( <var class="var">void</var>)</code></dt>
</dl>

<p>It is not possible to query for insecure hash algorithms directly
(only indirectly through the signature API).
</p>

<hr>
</div>
<div class="section-level-extent" id="Overriding-the-parameter-verification-profile">
<div class="nav-panel">
<p>
Next: <a href="#Overriding-the-default-priority-string" accesskey="n" rel="next">Overriding the default priority string</a>, Previous: <a href="#Querying-for-disabled-algorithms-and-protocols" accesskey="p" rel="prev">Querying for disabled algorithms and protocols</a>, Up: <a href="#System_002dwide-configuration-of-the-library" accesskey="u" rel="up">System-wide configuration of the library</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Overriding-the-parameter-verification-profile-1"><span>8.4 Overriding the parameter verification profile<a class="copiable-link" href="#Overriding-the-parameter-verification-profile-1"> &para;</a></span></h3>

<p>When verifying a certificate or TLS session parameters, GnuTLS uses a set
of profiles associated with the session to determine whether the parameters
seen in the session are acceptable. For example, whether the RSA public key
size as seen on the wire, or the Diffie-Hellman parameters for the session.
These profiles are normally set using the <code class="code">%PROFILE</code> priority string
(see <a class="ref" href="#Priority-Strings">Priority strings</a> and <a class="ref" href="#Selecting-cryptographic-key-sizes">Selecting cryptographic key sizes</a>).
</p>
<p>It is possible to set the low bar profile that applications cannot override
using the following.
</p>
<div class="example">
<pre class="example-preformatted">[overrides]

# do not allow applications use the LOW or VERY-WEAK profiles.
min-verification-profile = legacy

</pre></div>

<hr>
</div>
<div class="section-level-extent" id="Overriding-the-default-priority-string">
<div class="nav-panel">
<p>
Next: <a href="#Enabling-TLS-certificate-compression" accesskey="n" rel="next">Enabling TLS certificate compression</a>, Previous: <a href="#Overriding-the-parameter-verification-profile" accesskey="p" rel="prev">Overriding the parameter verification profile</a>, Up: <a href="#System_002dwide-configuration-of-the-library" accesskey="u" rel="up">System-wide configuration of the library</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Overriding-the-default-priority-string-1"><span>8.5 Overriding the default priority string<a class="copiable-link" href="#Overriding-the-default-priority-string-1"> &para;</a></span></h3>

<p>GnuTLS uses default priority string which is defined at compiled
time. Usually it is set to <code class="code">NORMAL</code>. This override allows to set
the default priority string to something more appropriate for a given
deployment.
</p>
<p>Below example sets a more specific default priority string.
</p><div class="example">
<pre class="example-preformatted">[overrides]
default-priority-string = SECURE128:-VERS-TLS-ALL:+VERS-TLS1.3

</pre></div>


<hr>
</div>
<div class="section-level-extent" id="Enabling-TLS-certificate-compression">
<div class="nav-panel">
<p>
Next: <a href="#Enabling_002fDisabling-system_002facceleration-protocols" accesskey="n" rel="next">Enabling/Disabling system/acceleration protocols</a>, Previous: <a href="#Overriding-the-default-priority-string" accesskey="p" rel="prev">Overriding the default priority string</a>, Up: <a href="#System_002dwide-configuration-of-the-library" accesskey="u" rel="up">System-wide configuration of the library</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Enabling-TLS-certificate-compression-1"><span>8.6 Enabling TLS certificate compression<a class="copiable-link" href="#Enabling-TLS-certificate-compression-1"> &para;</a></span></h3>

<p>This option can be used to enable certificate compression in TLS 1.3 handshake.
Note that setting certificate compression algorithms does not guarantee that
the certificate will be compressed. Setting certificate compression algorithms
will indicate to the peer which compression methods are supported and the peer
may decide to compress the certificate with one of these methods. Algorithms
that appear earlier in the list will be prefered over those appearing later.
</p>
<p>Below example shows how to enable the TLS certificate compression.
</p><div class="example">
<pre class="example-preformatted">[overrides]
cert-compression-alg = brotli
cert-compression-alg = zstd
cert-compression-alg = zlib

</pre></div>


<hr>
</div>
<div class="section-level-extent" id="Enabling_002fDisabling-system_002facceleration-protocols">
<div class="nav-panel">
<p>
Next: <a href="#Enabling_002fDisabling-RSAES_002dPKCS1_002dv1_005f5" accesskey="n" rel="next">Enabling/Disabling RSAES-PKCS1-v1_5</a>, Previous: <a href="#Enabling-TLS-certificate-compression" accesskey="p" rel="prev">Enabling TLS certificate compression</a>, Up: <a href="#System_002dwide-configuration-of-the-library" accesskey="u" rel="up">System-wide configuration of the library</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Enabling_002fDisabling-system_002facceleration-protocols-1"><span>8.7 Enabling/Disabling system/acceleration protocols<a class="copiable-link" href="#Enabling_002fDisabling-system_002facceleration-protocols-1"> &para;</a></span></h3>
<p>The following options can overwrite default behavior of protocols system-wide.
</p><div class="example">
<pre class="example-preformatted">[global]
ktls = true

</pre></div>
<ul class="mini-toc">
<li><a href="#Enabling-kTLS" accesskey="1">Enabling kTLS</a></li>
</ul>
<hr>
<div class="subsection-level-extent" id="Enabling-kTLS">
<div class="nav-panel">
<p>
Up: <a href="#Enabling_002fDisabling-system_002facceleration-protocols" accesskey="u" rel="up">Enabling/Disabling system/acceleration protocols</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h4 class="subsection" id="Enabling-kTLS-1"><span>8.7.1 Enabling kTLS<a class="copiable-link" href="#Enabling-kTLS-1"> &para;</a></span></h4>
<p>When GnuTLS is build with -–enable-ktls configuration, KTLS is disabled by default.
This can be enabled by setting <code class="code">ktls = true</code> in <code class="code">[global]</code> section.
</p>
<p>kTLS requires that the system support kTLS <a class="ref" href="#kTLS-_0028Kernel-TLS_0029">kTLS (Kernel TLS)</a>.
</p>
<hr>
</div>
</div>
<div class="section-level-extent" id="Enabling_002fDisabling-RSAES_002dPKCS1_002dv1_005f5">
<div class="nav-panel">
<p>
Next: <a href="#Using-PKCS_002311-module-as-cryptographic-backend" accesskey="n" rel="next">Using PKCS#11 module as cryptographic backend</a>, Previous: <a href="#Enabling_002fDisabling-system_002facceleration-protocols" accesskey="p" rel="prev">Enabling/Disabling system/acceleration protocols</a>, Up: <a href="#System_002dwide-configuration-of-the-library" accesskey="u" rel="up">System-wide configuration of the library</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Enabling_002fDisabling-RSAES_002dPKCS1_002dv1_005f5-1"><span>8.8 Enabling/Disabling RSAES-PKCS1-v1_5<a class="copiable-link" href="#Enabling_002fDisabling-RSAES_002dPKCS1_002dv1_005f5-1"> &para;</a></span></h3>

<p>This option can be used to enable/disable RSA PKCS1 v1.5 encryption and decryption
in GnuTLS. The RSAES-PKCS1-v1_5 is enabled by default.
</p>
<p>Below example shows how to explicitely disable the RSAES-PKCS1-v1_5.
</p><div class="example">
<pre class="example-preformatted">[overrides]
allow-rsa-pkcs1-encrypt = false
</pre></div>


<hr>
</div>
<div class="section-level-extent" id="Using-PKCS_002311-module-as-cryptographic-backend">
<div class="nav-panel">
<p>
Previous: <a href="#Enabling_002fDisabling-RSAES_002dPKCS1_002dv1_005f5" accesskey="p" rel="prev">Enabling/Disabling RSAES-PKCS1-v1_5</a>, Up: <a href="#System_002dwide-configuration-of-the-library" accesskey="u" rel="up">System-wide configuration of the library</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Using-PKCS_002311-module-as-cryptographic-backend-1"><span>8.9 Using PKCS#11 module as cryptographic backend<a class="copiable-link" href="#Using-PKCS_002311-module-as-cryptographic-backend-1"> &para;</a></span></h3>

<p>Since version 3.8.10 it is possible to plug a PKCS#11 module into GnuTLS
and override the default cryptographic backend of the library with the
cryptographic functions provided by the module.
</p>
<p>A PKCS#11 module can be configured to serve as cryptographic backend by adding
<code class="code">url</code> and <code class="code">pin</code> in the <code class="code">[provider]</code> section.
</p>
<ul class="itemize mark-bullet">
<li><code class="code">url</code>: URL of the PKCS#11 module.
</li><li><code class="code">pin</code>: PIN for logging into the PKCS#11 token.
</li></ul>

<ul class="mini-toc">
<li><a href="#Examples-1" accesskey="1">Examples</a></li>
</ul>
<div class="subsection-level-extent" id="Examples-1">
<h4 class="subsection"><span>8.9.1 Examples<a class="copiable-link" href="#Examples-1"> &para;</a></span></h4>

<p>The following example shows how to use a PKCS#11 module as cryptographic backend.
Note that the module has to be initialized first.
</p>
<div class="example">
<pre class="example-preformatted">[provider]
url = pkcs11:model=v1;manufacturer=Kryoptic%20Project;token=Kryoptic%20Token
pin = 1234
</pre></div>

<hr>
</div>
</div>
</div>
<div class="chapter-level-extent" id="Using-GnuTLS-as-a-cryptographic-library">
<div class="nav-panel">
<p>
Next: <a href="#Other-included-programs" accesskey="n" rel="next">Other included programs</a>, Previous: <a href="#System_002dwide-configuration-of-the-library" accesskey="p" rel="prev">System-wide configuration of the library</a>, Up: <a href="#Top" accesskey="u" rel="up">GnuTLS</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h2 class="chapter" id="Using-GnuTLS-as-a-cryptographic-library-1"><span>9 Using GnuTLS as a cryptographic library<a class="copiable-link" href="#Using-GnuTLS-as-a-cryptographic-library-1"> &para;</a></span></h2>

<p><abbr class="acronym">GnuTLS</abbr> is not a low-level cryptographic library, i.e., 
it does not provide access to basic cryptographic primitives. However
it abstracts the internal cryptographic back-end (see <a class="ref" href="#Cryptographic-Backend">Cryptographic Backend</a>),
providing symmetric crypto, hash and HMAC algorithms, as well access
to the random number generation. For a low-level crypto API the usage of nettle
<a class="footnote" id="DOCF21" href="#FOOT21"><sup>21</sup></a> library is recommended.
</p>

<ul class="mini-toc">
<li><a href="#Symmetric-algorithms" accesskey="1">Symmetric algorithms</a></li>
<li><a href="#Public-key-algorithms" accesskey="2">Public key algorithms</a></li>
<li><a href="#Cryptographic-Message-Syntax-_002f-PKCS7" accesskey="3">Cryptographic Message Syntax / PKCS7</a></li>
<li><a href="#Hash-and-MAC-functions" accesskey="4">Hash and MAC functions</a></li>
<li><a href="#Random-number-generation" accesskey="5">Random number generation</a></li>
<li><a href="#Overriding-algorithms" accesskey="6">Overriding algorithms</a></li>
</ul>
<hr>
<div class="section-level-extent" id="Symmetric-algorithms">
<div class="nav-panel">
<p>
Next: <a href="#Public-key-algorithms" accesskey="n" rel="next">Public key algorithms</a>, Up: <a href="#Using-GnuTLS-as-a-cryptographic-library" accesskey="u" rel="up">Using GnuTLS as a cryptographic library</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Symmetric-algorithms-1"><span>9.1 Symmetric algorithms<a class="copiable-link" href="#Symmetric-algorithms-1"> &para;</a></span></h3>
<a class="index-entry-id" id="index-symmetric-algorithms"></a>
<a class="index-entry-id" id="index-symmetric-cryptography"></a>

<p>The available functions to access symmetric crypto algorithms operations
are listed in the sections below. The supported algorithms are the algorithms required by the TLS protocol.
They are listed in <a class="ref" href="#gnutls_005fcipher_005falgorithm_005ft">Figure 9.1</a>. Note that there two
types of ciphers, the ones providing an authenticated-encryption with
associated data (AEAD), and the legacy ciphers which provide raw access
to the ciphers. We recommend the use of the AEAD ciphers under the AEAD APIs
for new applications as they are designed to minimize the misuse of
cryptographic primitives.
</p>
<div class="float" id="gnutls_005fcipher_005falgorithm_005ft">


<dl class="table">
<dt><code class="code">GNUTLS_CIPHER_UNKNOWN</code></dt>
<dd><p>Value to identify an unknown/unsupported algorithm.
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_NULL</code></dt>
<dd><p>The NULL (identity) encryption algorithm.
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_ARCFOUR_128</code></dt>
<dd><p>ARCFOUR stream cipher with 128-bit keys.
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_3DES_CBC</code></dt>
<dd><p>3DES in CBC mode.
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_AES_128_CBC</code></dt>
<dd><p>AES in CBC mode with 128-bit keys.
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_AES_256_CBC</code></dt>
<dd><p>AES in CBC mode with 256-bit keys.
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_ARCFOUR_40</code></dt>
<dd><p>ARCFOUR stream cipher with 40-bit keys.
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_CAMELLIA_128_CBC</code></dt>
<dd><p>Camellia in CBC mode with 128-bit keys.
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_CAMELLIA_256_CBC</code></dt>
<dd><p>Camellia in CBC mode with 256-bit keys.
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_AES_192_CBC</code></dt>
<dd><p>AES in CBC mode with 192-bit keys.
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_AES_128_GCM</code></dt>
<dd><p>AES in GCM mode with 128-bit keys (AEAD).
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_AES_256_GCM</code></dt>
<dd><p>AES in GCM mode with 256-bit keys (AEAD).
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_CAMELLIA_192_CBC</code></dt>
<dd><p>Camellia in CBC mode with 192-bit keys.
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_SALSA20_256</code></dt>
<dd><p>Salsa20 with 256-bit keys.
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_ESTREAM_SALSA20_256</code></dt>
<dd><p>Estream&rsquo;s Salsa20 variant with 256-bit keys.
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_CAMELLIA_128_GCM</code></dt>
<dd><p>CAMELLIA in GCM mode with 128-bit keys (AEAD).
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_CAMELLIA_256_GCM</code></dt>
<dd><p>CAMELLIA in GCM mode with 256-bit keys (AEAD).
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_RC2_40_CBC</code></dt>
<dd><p>RC2 in CBC mode with 40-bit keys.
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_DES_CBC</code></dt>
<dd><p>DES in CBC mode (56-bit keys).
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_AES_128_CCM</code></dt>
<dd><p>AES in CCM mode with 128-bit keys (AEAD).
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_AES_256_CCM</code></dt>
<dd><p>AES in CCM mode with 256-bit keys (AEAD).
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_AES_128_CCM_8</code></dt>
<dd><p>AES in CCM mode with 64-bit tag and 128-bit keys (AEAD).
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_AES_256_CCM_8</code></dt>
<dd><p>AES in CCM mode with 64-bit tag and 256-bit keys (AEAD).
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_CHACHA20_POLY1305</code></dt>
<dd><p>The Chacha20 cipher with the Poly1305 authenticator (AEAD).
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_GOST28147_TC26Z_CFB</code></dt>
<dd><p>GOST 28147-89 (Magma) cipher in CFB mode with TC26 Z S-box.
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_GOST28147_CPA_CFB</code></dt>
<dd><p>GOST 28147-89 (Magma) cipher in CFB mode with CryptoPro A S-box.
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_GOST28147_CPB_CFB</code></dt>
<dd><p>GOST 28147-89 (Magma) cipher in CFB mode with CryptoPro B S-box.
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_GOST28147_CPC_CFB</code></dt>
<dd><p>GOST 28147-89 (Magma) cipher in CFB mode with CryptoPro C S-box.
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_GOST28147_CPD_CFB</code></dt>
<dd><p>GOST 28147-89 (Magma) cipher in CFB mode with CryptoPro D S-box.
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_AES_128_CFB8</code></dt>
<dd><p>AES in CFB8 mode with 128-bit keys.
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_AES_192_CFB8</code></dt>
<dd><p>AES in CFB8 mode with 192-bit keys.
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_AES_256_CFB8</code></dt>
<dd><p>AES in CFB8 mode with 256-bit keys.
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_AES_128_XTS</code></dt>
<dd><p>AES in XTS mode with 128-bit key + 128bit tweak key.
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_AES_256_XTS</code></dt>
<dd><p>AES in XTS mode with 256-bit key + 256bit tweak key.
Note that the XTS ciphers are message oriented.
The whole message needs to be provided with a single call, because
cipher-stealing requires to know where the message actually terminates
in order to be able to compute where the stealing occurs.
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_GOST28147_TC26Z_CNT</code></dt>
<dd><p>GOST 28147-89 (Magma) cipher in CNT mode with TC26 Z S-box.
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_CHACHA20_64</code></dt>
<dd><p>Chacha20 cipher with 64-bit nonces and 64-bit block counters.
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_CHACHA20_32</code></dt>
<dd><p>Chacha20 cipher with 96-bit nonces and 32-bit block counters.
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_AES_128_SIV</code></dt>
<dd><p>AES in SIV mode with 128-bit key.
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_AES_256_SIV</code></dt>
<dd><p>AES in SIV mode with 256-bit key.
Note that the SIV ciphers can only be used with
the AEAD interface, and the IV plays a role as
the authentication tag while it is prepended to
the cipher text.
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_AES_192_GCM</code></dt>
<dd><p>AES in GCM mode with 192-bit keys (AEAD).
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_MAGMA_CTR_ACPKM</code></dt>
<dd><p>GOST R 34.12-2015 (Magma) cipher in CTR-ACPKM mode.
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_KUZNYECHIK_CTR_ACPKM</code></dt>
<dd><p>GOST R 34.12-2015 (Kuznyechik) cipher in CTR-ACPKM mode.
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_AES_128_SIV_GCM</code></dt>
<dd><p>AES in SIV-GCM mode with 128-bit key.
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_AES_256_SIV_GCM</code></dt>
<dd><p>AES in SIV-GCM mode with 256-bit key.
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_AES_128_CFB</code></dt>
<dd><p>AES in CFB mode with 128-bit keys.
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_AES_192_CFB</code></dt>
<dd><p>AES in CFB mode with 192-bit keys.
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_AES_256_CFB</code></dt>
<dd><p>AES in CFB mode with 256-bit keys.
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_IDEA_PGP_CFB</code></dt>
<dd><p>IDEA in CFB mode (placeholder - unsupported).
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_3DES_PGP_CFB</code></dt>
<dd><p>3DES in CFB mode (placeholder - unsupported).
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_CAST5_PGP_CFB</code></dt>
<dd><p>CAST5 in CFB mode (placeholder - unsupported).
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_BLOWFISH_PGP_CFB</code></dt>
<dd><p>Blowfish in CFB mode (placeholder - unsupported).
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_SAFER_SK128_PGP_CFB</code></dt>
<dd><p>Safer-SK in CFB mode with 128-bit keys (placeholder - unsupported).
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_AES128_PGP_CFB</code></dt>
<dd><p>AES in CFB mode with 128-bit keys (placeholder - unsupported).
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_AES192_PGP_CFB</code></dt>
<dd><p>AES in CFB mode with 192-bit keys (placeholder - unsupported).
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_AES256_PGP_CFB</code></dt>
<dd><p>AES in CFB mode with 256-bit keys (placeholder - unsupported).
</p></dd>
<dt><code class="code">GNUTLS_CIPHER_TWOFISH_PGP_CFB</code></dt>
<dd><p>Twofish in CFB mode (placeholder - unsupported).
</p></dd>
</dl>
<div class="caption"><p><strong class="strong">Figure 9.1: </strong>The supported ciphers.</p></div></div>
<h4 class="subheading" id="Authenticated_002dencryption-API"><span>Authenticated-encryption API<a class="copiable-link" href="#Authenticated_002dencryption-API"> &para;</a></span></h4>

<p>The AEAD API provides access to all ciphers supported by GnuTLS which support
authenticated encryption with associated data; these ciphers are marked with
the AEAD keyword on the table above. The AEAD cipher API is
particularly suitable for message or packet-encryption as it provides
authentication and encryption on the same API. See <code class="code">RFC5116</code> for more
information on authenticated encryption.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005faead_005fcipher_005finit">gnutls_aead_cipher_init</a> (gnutls_aead_cipher_hd_t * <var class="var">handle</var>, gnutls_cipher_algorithm_t <var class="var">cipher</var>, const gnutls_datum_t * <var class="var">key</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005faead_005fcipher_005fencrypt">gnutls_aead_cipher_encrypt</a> (gnutls_aead_cipher_hd_t <var class="var">handle</var>, const void * <var class="var">nonce</var>, size_t <var class="var">nonce_len</var>, const void * <var class="var">auth</var>, size_t <var class="var">auth_len</var>, size_t <var class="var">tag_size</var>, const void * <var class="var">ptext</var>, size_t <var class="var">ptext_len</var>, void * <var class="var">ctext</var>, size_t * <var class="var">ctext_len</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005faead_005fcipher_005fdecrypt">gnutls_aead_cipher_decrypt</a> (gnutls_aead_cipher_hd_t <var class="var">handle</var>, const void * <var class="var">nonce</var>, size_t <var class="var">nonce_len</var>, const void * <var class="var">auth</var>, size_t <var class="var">auth_len</var>, size_t <var class="var">tag_size</var>, const void * <var class="var">ctext</var>, size_t <var class="var">ctext_len</var>, void * <var class="var">ptext</var>, size_t * <var class="var">ptext_len</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005faead_005fcipher_005fdeinit">gnutls_aead_cipher_deinit</a> (gnutls_aead_cipher_hd_t <var class="var">handle</var>)</code></dt>
</dl>

<p>Because the encryption function above may be difficult to use with
scattered data, we provide the following API.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005faead_005fcipher_005fencryptv"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_aead_cipher_encryptv</strong> <code class="def-code-arguments">(gnutls_aead_cipher_hd_t <var class="var">handle</var>, const void * <var class="var">nonce</var>, size_t <var class="var">nonce_len</var>, const giovec_t * <var class="var">auth_iov</var>, int <var class="var">auth_iovcnt</var>, size_t <var class="var">tag_size</var>, const giovec_t * <var class="var">iov</var>, int <var class="var">iovcnt</var>, void * <var class="var">ctext</var>, size_t * <var class="var">ctext_len</var>)</code><a class="copiable-link" href="#index-gnutls_005faead_005fcipher_005fencryptv"> &para;</a></span></dt>
<dd><p><var class="var">handle</var>: is a <code class="code">gnutls_aead_cipher_hd_t</code>  type.
</p>
<p><var class="var">nonce</var>: the nonce to set
</p>
<p><var class="var">nonce_len</var>: The length of the nonce
</p>
<p><var class="var">auth_iov</var>: additional data to be authenticated
</p>
<p><var class="var">auth_iovcnt</var>: The number of buffers in  <code class="code">auth_iov</code> 
</p>
<p><var class="var">tag_size</var>: The size of the tag to use (use zero for the default)
</p>
<p><var class="var">iov</var>: the data to be encrypted
</p>
<p><var class="var">iovcnt</var>: The number of buffers in  <code class="code">iov</code> 
</p>
<p><var class="var">ctext</var>: the encrypted data including authentication tag
</p>
<p><var class="var">ctext_len</var>: the length of encrypted data (initially must hold the maximum available size, including space for tag)
</p>
<p>This function will encrypt the provided data buffers using the algorithm
specified by the context. The output data will contain the
authentication tag.
</p>
<p><strong class="strong">Returns:</strong> Zero or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 3.6.3
</p></dd></dl>

<h4 class="subheading" id="Legacy-API"><span>Legacy API<a class="copiable-link" href="#Legacy-API"> &para;</a></span></h4>

<p>The legacy API provides low-level access to all legacy ciphers supported by GnuTLS,
and some of the AEAD ciphers (e.g., AES-GCM and CHACHA20). The restrictions
of the nettle library implementation of the ciphers apply verbatim to this
API<a class="footnote" id="DOCF22" href="#FOOT22"><sup>22</sup></a>.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fcipher_005finit">gnutls_cipher_init</a> (gnutls_cipher_hd_t * <var class="var">handle</var>, gnutls_cipher_algorithm_t <var class="var">cipher</var>, const gnutls_datum_t * <var class="var">key</var>, const gnutls_datum_t * <var class="var">iv</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fcipher_005fencrypt2">gnutls_cipher_encrypt2</a> (gnutls_cipher_hd_t <var class="var">handle</var>, const void * <var class="var">ptext</var>, size_t <var class="var">ptext_len</var>, void * <var class="var">ctext</var>, size_t <var class="var">ctext_len</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fcipher_005fdecrypt2">gnutls_cipher_decrypt2</a> (gnutls_cipher_hd_t <var class="var">handle</var>, const void * <var class="var">ctext</var>, size_t <var class="var">ctext_len</var>, void * <var class="var">ptext</var>, size_t <var class="var">ptext_len</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fcipher_005fset_005fiv">gnutls_cipher_set_iv</a> (gnutls_cipher_hd_t <var class="var">handle</var>, void * <var class="var">iv</var>, size_t <var class="var">ivlen</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fcipher_005fdeinit">gnutls_cipher_deinit</a> (gnutls_cipher_hd_t <var class="var">handle</var>)</code></dt>
</dl>

<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fcipher_005fadd_005fauth">gnutls_cipher_add_auth</a> (gnutls_cipher_hd_t <var class="var">handle</var>, const void * <var class="var">ptext</var>, size_t <var class="var">ptext_size</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fcipher_005ftag">gnutls_cipher_tag</a> (gnutls_cipher_hd_t <var class="var">handle</var>, void * <var class="var">tag</var>, size_t <var class="var">tag_size</var>)</code></dt>
</dl>
<p>While the latter two functions allow the same API can be used with authenticated encryption ciphers, 
it is recommended to use the following functions which are solely for AEAD ciphers. The latter
API is designed to be simple to use and also hard to misuse, by handling the tag verification
and addition in transparent way.
</p>
<hr>
</div>
<div class="section-level-extent" id="Public-key-algorithms">
<div class="nav-panel">
<p>
Next: <a href="#Cryptographic-Message-Syntax-_002f-PKCS7" accesskey="n" rel="next">Cryptographic Message Syntax / PKCS7</a>, Previous: <a href="#Symmetric-algorithms" accesskey="p" rel="prev">Symmetric algorithms</a>, Up: <a href="#Using-GnuTLS-as-a-cryptographic-library" accesskey="u" rel="up">Using GnuTLS as a cryptographic library</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Public-key-algorithms-1"><span>9.2 Public key algorithms<a class="copiable-link" href="#Public-key-algorithms-1"> &para;</a></span></h3>
<a class="index-entry-id" id="index-public-key-algorithms"></a>

<p>Public key cryptography algorithms such as RSA, DSA and ECDSA, are
accessed using the abstract key API in <a class="ref" href="#Abstract-key-types">Abstract key types</a>. This
is a high level API with the advantage of transparently handling keys
stored in memory and keys present in smart cards.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fprivkey_005finit">gnutls_privkey_init</a> (gnutls_privkey_t * <var class="var">key</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fprivkey_005fimport_005furl">gnutls_privkey_import_url</a> (gnutls_privkey_t <var class="var">key</var>, const char * <var class="var">url</var>, unsigned int <var class="var">flags</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fprivkey_005fimport_005fx509_005fraw">gnutls_privkey_import_x509_raw</a> (gnutls_privkey_t <var class="var">pkey</var>, const gnutls_datum_t * <var class="var">data</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, const char * <var class="var">password</var>, unsigned int <var class="var">flags</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fprivkey_005fsign_005fdata">gnutls_privkey_sign_data</a> (gnutls_privkey_t <var class="var">signer</var>, gnutls_digest_algorithm_t <var class="var">hash</var>, unsigned int <var class="var">flags</var>, const gnutls_datum_t * <var class="var">data</var>, gnutls_datum_t * <var class="var">signature</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fprivkey_005fsign_005fhash">gnutls_privkey_sign_hash</a> (gnutls_privkey_t <var class="var">signer</var>, gnutls_digest_algorithm_t <var class="var">hash_algo</var>, unsigned int <var class="var">flags</var>, const gnutls_datum_t * <var class="var">hash_data</var>, gnutls_datum_t * <var class="var">signature</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fprivkey_005fdeinit">gnutls_privkey_deinit</a> (gnutls_privkey_t <var class="var">key</var>)</code></dt>
</dl>

<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpubkey_005finit">gnutls_pubkey_init</a> (gnutls_pubkey_t * <var class="var">key</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpubkey_005fimport_005furl">gnutls_pubkey_import_url</a> (gnutls_pubkey_t <var class="var">key</var>, const char * <var class="var">url</var>, unsigned int <var class="var">flags</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpubkey_005fimport_005fx509">gnutls_pubkey_import_x509</a> (gnutls_pubkey_t <var class="var">key</var>, gnutls_x509_crt_t <var class="var">crt</var>, unsigned int <var class="var">flags</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpubkey_005fverify_005fdata2">gnutls_pubkey_verify_data2</a> (gnutls_pubkey_t <var class="var">pubkey</var>, gnutls_sign_algorithm_t <var class="var">algo</var>, unsigned int <var class="var">flags</var>, const gnutls_datum_t * <var class="var">data</var>, const gnutls_datum_t * <var class="var">signature</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpubkey_005fverify_005fhash2">gnutls_pubkey_verify_hash2</a> (gnutls_pubkey_t <var class="var">key</var>, gnutls_sign_algorithm_t <var class="var">algo</var>, unsigned int <var class="var">flags</var>, const gnutls_datum_t * <var class="var">hash</var>, const gnutls_datum_t * <var class="var">signature</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fpubkey_005fdeinit">gnutls_pubkey_deinit</a> (gnutls_pubkey_t <var class="var">key</var>)</code></dt>
</dl>

<p>Keys stored in memory can be imported using functions like
<a class="ref" href="#gnutls_005fprivkey_005fimport_005fx509_005fraw">gnutls_privkey_import_x509_raw</a>, while keys on smart cards or HSMs
should be imported using their PKCS#11 URL with
<a class="ref" href="#gnutls_005fprivkey_005fimport_005furl">gnutls_privkey_import_url</a>.
</p>
<p>If any of the smart card operations require PIN, that should be provided
either by setting the global PIN function
(<a class="ref" href="#gnutls_005fpkcs11_005fset_005fpin_005ffunction">gnutls_pkcs11_set_pin_function</a>), or better with the targeted to
structures functions such as <a class="ref" href="#gnutls_005fprivkey_005fset_005fpin_005ffunction">gnutls_privkey_set_pin_function</a>.
</p>

<ul class="mini-toc">
<li><a href="#Key-generation-2" accesskey="1">Key generation</a></li>
</ul>
<div class="subsection-level-extent" id="Key-generation-2">
<h4 class="subsection"><span>9.2.1 Key generation<a class="copiable-link" href="#Key-generation-2"> &para;</a></span></h4>

<p>All supported key types (including RSA, DSA, ECDSA, Ed25519, Ed448) can be generated
with GnuTLS. They can be generated with the simpler <a class="ref" href="#gnutls_005fprivkey_005fgenerate">gnutls_privkey_generate</a>
or with the more advanced <a class="ref" href="#gnutls_005fprivkey_005fgenerate2">gnutls_privkey_generate2</a>.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fgenerate2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_generate2</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">pkey</var>, gnutls_pk_algorithm_t <var class="var">algo</var>, unsigned int <var class="var">bits</var>, unsigned int <var class="var">flags</var>, const gnutls_keygen_data_st * <var class="var">data</var>, unsigned <var class="var">data_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fgenerate2"> &para;</a></span></dt>
<dd><p><var class="var">pkey</var>: The private key
</p>
<p><var class="var">algo</var>: is one of the algorithms in <code class="code">gnutls_pk_algorithm_t</code> .
</p>
<p><var class="var">bits</var>: the size of the modulus
</p>
<p><var class="var">flags</var>: Must be zero or flags from <code class="code">gnutls_privkey_flags_t</code> .
</p>
<p><var class="var">data</var>: Allow specifying <code class="code">gnutls_keygen_data_st</code>  types such as the seed to be used.
</p>
<p><var class="var">data_size</var>: The number of  <code class="code">data</code> available.
</p>
<p>This function will generate a random private key. Note that this
function must be called on an initialized private key.
</p>
<p>The flag <code class="code">GNUTLS_PRIVKEY_FLAG_PROVABLE</code> 
instructs the key generation process to use algorithms like Shawe-Taylor
(from FIPS PUB186-4) which generate provable parameters out of a seed
for RSA and DSA keys. On DSA keys the PQG parameters are generated using the
seed, while on RSA the two primes. To specify an explicit seed
(by default a random seed is used), use the  <code class="code">data</code> with a <code class="code">GNUTLS_KEYGEN_SEED</code> 
type.
</p>
<p>Note that when generating an elliptic curve key, the curve
can be substituted in the place of the bits parameter using the
<code class="code">GNUTLS_CURVE_TO_BITS()</code>  macro.
</p>
<p>To export the generated keys in memory or in files it is recommended to use the
PKCS<code class="code">8</code>  form as it can handle all key types, and can store additional parameters
such as the seed, in case of provable RSA or DSA keys.
Generated keys can be exported in memory using <code class="code">gnutls_privkey_export_x509()</code> ,
and then with <code class="code">gnutls_x509_privkey_export2_pkcs8()</code> .
</p>
<p>If key generation is part of your application, avoid setting the number
of bits directly, and instead use <code class="code">gnutls_sec_param_to_pk_bits()</code> .
That way the generated keys will adapt to the security levels
of the underlying GnuTLS library.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.5.0
</p></dd></dl>

<hr>
</div>
</div>
<div class="section-level-extent" id="Cryptographic-Message-Syntax-_002f-PKCS7">
<div class="nav-panel">
<p>
Next: <a href="#Hash-and-MAC-functions" accesskey="n" rel="next">Hash and MAC functions</a>, Previous: <a href="#Public-key-algorithms" accesskey="p" rel="prev">Public key algorithms</a>, Up: <a href="#Using-GnuTLS-as-a-cryptographic-library" accesskey="u" rel="up">Using GnuTLS as a cryptographic library</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Cryptographic-Message-Syntax-_002f-PKCS7-1"><span>9.3 Cryptographic Message Syntax / PKCS7<a class="copiable-link" href="#Cryptographic-Message-Syntax-_002f-PKCS7-1"> &para;</a></span></h3>
<a class="index-entry-id" id="index-public-key-algorithms-1"></a>
<a class="index-entry-id" id="index-cryptographic-message-syntax"></a>
<a class="index-entry-id" id="index-file-signing"></a>
<a class="index-entry-id" id="index-CMS"></a>
<a class="index-entry-id" id="index-PKCS-_00237"></a>

<p>The CMS or PKCS #7 format is a commonly used format for digital signatures.
PKCS #7 is the name of the original standard when published by RSA, though
today the standard is adopted by IETF under the name CMS.
</p>
<p>The standards include multiple ways of signing a digital document, e.g.,
by embedding the data into the signature, or creating detached signatures of the data,
including a timestamp, additional certificates etc. In certain cases the
same format is also used to transport lists of certificates and CRLs.
</p>
<p>It is a relatively popular standard to sign structures, and is being used to
sign in PDF files, as well as for signing kernel modules and other
structures.
</p>
<p>In GnuTLS, the basic functions to initialize, deinitialize, import, export or print information
about a PKCS #7 structure are listed below.
</p><dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpkcs7_005finit">gnutls_pkcs7_init</a> (gnutls_pkcs7_t * <var class="var">pkcs7</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fpkcs7_005fdeinit">gnutls_pkcs7_deinit</a> (gnutls_pkcs7_t <var class="var">pkcs7</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpkcs7_005fexport2">gnutls_pkcs7_export2</a> (gnutls_pkcs7_t <var class="var">pkcs7</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, gnutls_datum_t * <var class="var">out</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpkcs7_005fimport">gnutls_pkcs7_import</a> (gnutls_pkcs7_t <var class="var">pkcs7</var>, const gnutls_datum_t * <var class="var">data</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpkcs7_005fprint">gnutls_pkcs7_print</a> (gnutls_pkcs7_t <var class="var">pkcs7</var>, gnutls_certificate_print_formats_t <var class="var">format</var>, gnutls_datum_t * <var class="var">out</var>)</code></dt>
</dl>

<p>The following functions allow the verification of a structure using either a trust list, or
individual certificates. The <a class="ref" href="#gnutls_005fpkcs7_005fsign">gnutls_pkcs7_sign</a> function is the data signing function.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpkcs7_005fverify_005fdirect">gnutls_pkcs7_verify_direct</a> (gnutls_pkcs7_t <var class="var">pkcs7</var>, gnutls_x509_crt_t <var class="var">signer</var>, unsigned <var class="var">idx</var>, const gnutls_datum_t * <var class="var">data</var>, unsigned <var class="var">flags</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpkcs7_005fverify">gnutls_pkcs7_verify</a> (gnutls_pkcs7_t <var class="var">pkcs7</var>, gnutls_x509_trust_list_t <var class="var">tl</var>, gnutls_typed_vdata_st * <var class="var">vdata</var>, unsigned int <var class="var">vdata_size</var>, unsigned <var class="var">idx</var>, const gnutls_datum_t * <var class="var">data</var>, unsigned <var class="var">flags</var>)</code></dt>
</dl>





<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs7_005fsign"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs7_sign</strong> <code class="def-code-arguments">(gnutls_pkcs7_t <var class="var">pkcs7</var>, gnutls_x509_crt_t <var class="var">signer</var>, gnutls_privkey_t <var class="var">signer_key</var>, const gnutls_datum_t * <var class="var">data</var>, gnutls_pkcs7_attrs_t <var class="var">signed_attrs</var>, gnutls_pkcs7_attrs_t <var class="var">unsigned_attrs</var>, gnutls_digest_algorithm_t <var class="var">dig</var>, unsigned <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs7_005fsign"> &para;</a></span></dt>
<dd><p><var class="var">pkcs7</var>: should contain a <code class="code">gnutls_pkcs7_t</code>  type
</p>
<p><var class="var">signer</var>: the certificate to sign the structure
</p>
<p><var class="var">signer_key</var>: the key to sign the structure
</p>
<p><var class="var">data</var>: The data to be signed or <code class="code">NULL</code>  if the data are already embedded
</p>
<p><var class="var">signed_attrs</var>: Any additional attributes to be included in the signed ones (or <code class="code">NULL</code> )
</p>
<p><var class="var">unsigned_attrs</var>: Any additional attributes to be included in the unsigned ones (or <code class="code">NULL</code> )
</p>
<p><var class="var">dig</var>: The digest algorithm to use for signing
</p>
<p><var class="var">flags</var>: Should be zero or one of <code class="code">GNUTLS_PKCS7</code>  flags
</p>
<p>This function will add a signature in the provided PKCS <code class="code">7</code>  structure
for the provided data. Multiple signatures can be made with different
signers.
</p>
<p>The available flags are:
<code class="code">GNUTLS_PKCS7_EMBED_DATA</code> , <code class="code">GNUTLS_PKCS7_INCLUDE_TIME</code> , <code class="code">GNUTLS_PKCS7_INCLUDE_CERT</code> ,
and <code class="code">GNUTLS_PKCS7_WRITE_SPKI</code> . They are explained in the <code class="code">gnutls_pkcs7_sign_flags</code> 
definition.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.4.2
</p></dd></dl>

<div class="float" id="gnutls_005fpkcs7_005fsign_005fflags">


<dl class="table">
<dt><code class="code">GNUTLS_PKCS7_EMBED_DATA</code></dt>
<dd><p>The signed data will be embedded in the structure.
</p></dd>
<dt><code class="code">GNUTLS_PKCS7_INCLUDE_TIME</code></dt>
<dd><p>The signing time will be included in the structure.
</p></dd>
<dt><code class="code">GNUTLS_PKCS7_INCLUDE_CERT</code></dt>
<dd><p>The signer&rsquo;s certificate will be included in the cert list.
</p></dd>
<dt><code class="code">GNUTLS_PKCS7_WRITE_SPKI</code></dt>
<dd><p>Use the signer&rsquo;s key identifier instead of name.
</p></dd>
</dl>
<div class="caption"><p><strong class="strong">Figure 9.2: </strong>Flags applicable to gnutls_pkcs7_sign()</p></div></div>
<p>Other helper functions which allow to access the signatures, or certificates attached
in the structure are listed below.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpkcs7_005fget_005fsignature_005fcount">gnutls_pkcs7_get_signature_count</a> (gnutls_pkcs7_t <var class="var">pkcs7</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpkcs7_005fget_005fsignature_005finfo">gnutls_pkcs7_get_signature_info</a> (gnutls_pkcs7_t <var class="var">pkcs7</var>, unsigned <var class="var">idx</var>, gnutls_pkcs7_signature_info_st * <var class="var">info</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpkcs7_005fget_005fcrt_005fcount">gnutls_pkcs7_get_crt_count</a> (gnutls_pkcs7_t <var class="var">pkcs7</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpkcs7_005fget_005fcrt_005fraw2">gnutls_pkcs7_get_crt_raw2</a> (gnutls_pkcs7_t <var class="var">pkcs7</var>, unsigned <var class="var">indx</var>, gnutls_datum_t * <var class="var">cert</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpkcs7_005fget_005fcrl_005fcount">gnutls_pkcs7_get_crl_count</a> (gnutls_pkcs7_t <var class="var">pkcs7</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpkcs7_005fget_005fcrl_005fraw2">gnutls_pkcs7_get_crl_raw2</a> (gnutls_pkcs7_t <var class="var">pkcs7</var>, unsigned <var class="var">indx</var>, gnutls_datum_t * <var class="var">crl</var>)</code></dt>
</dl>

<p>To append certificates, or CRLs in the structure the following functions are provided.
</p><dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpkcs7_005fset_005fcrt_005fraw">gnutls_pkcs7_set_crt_raw</a> (gnutls_pkcs7_t <var class="var">pkcs7</var>, const gnutls_datum_t * <var class="var">crt</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpkcs7_005fset_005fcrt">gnutls_pkcs7_set_crt</a> (gnutls_pkcs7_t <var class="var">pkcs7</var>, gnutls_x509_crt_t <var class="var">crt</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpkcs7_005fset_005fcrl_005fraw">gnutls_pkcs7_set_crl_raw</a> (gnutls_pkcs7_t <var class="var">pkcs7</var>, const gnutls_datum_t * <var class="var">crl</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fpkcs7_005fset_005fcrl">gnutls_pkcs7_set_crl</a> (gnutls_pkcs7_t <var class="var">pkcs7</var>, gnutls_x509_crl_t <var class="var">crl</var>)</code></dt>
</dl>

<hr>
</div>
<div class="section-level-extent" id="Hash-and-MAC-functions">
<div class="nav-panel">
<p>
Next: <a href="#Random-number-generation" accesskey="n" rel="next">Random number generation</a>, Previous: <a href="#Cryptographic-Message-Syntax-_002f-PKCS7" accesskey="p" rel="prev">Cryptographic Message Syntax / PKCS7</a>, Up: <a href="#Using-GnuTLS-as-a-cryptographic-library" accesskey="u" rel="up">Using GnuTLS as a cryptographic library</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Hash-and-MAC-functions-1"><span>9.4 Hash and MAC functions<a class="copiable-link" href="#Hash-and-MAC-functions-1"> &para;</a></span></h3>
<a class="index-entry-id" id="index-hash-functions"></a>
<a class="index-entry-id" id="index-HMAC-functions"></a>
<a class="index-entry-id" id="index-MAC-functions"></a>

<p>The available operations to access hash functions and hash-MAC (HMAC) algorithms
are shown below. HMAC algorithms provided keyed hash functionality. The supported MAC and HMAC
algorithms are listed in <a class="ref" href="#gnutls_005fmac_005falgorithm_005ft">Figure 9.3</a>. Note that, despite the <code class="code">hmac</code> part 
in the name of the MAC functions listed below, they can be used either for HMAC or MAC operations.
</p>
<div class="float" id="gnutls_005fmac_005falgorithm_005ft">


<dl class="table">
<dt><code class="code">GNUTLS_MAC_UNKNOWN</code></dt>
<dd><p>Unknown MAC algorithm.
</p></dd>
<dt><code class="code">GNUTLS_MAC_NULL</code></dt>
<dd><p>NULL MAC algorithm (empty output).
</p></dd>
<dt><code class="code">GNUTLS_MAC_MD5</code></dt>
<dd><p>HMAC-MD5 algorithm.
</p></dd>
<dt><code class="code">GNUTLS_MAC_SHA1</code></dt>
<dd><p>HMAC-SHA-1 algorithm.
</p></dd>
<dt><code class="code">GNUTLS_MAC_RMD160</code></dt>
<dd><p>HMAC-RMD160 algorithm.
</p></dd>
<dt><code class="code">GNUTLS_MAC_MD2</code></dt>
<dd><p>HMAC-MD2 algorithm.
</p></dd>
<dt><code class="code">GNUTLS_MAC_SHA256</code></dt>
<dd><p>HMAC-SHA-256 algorithm.
</p></dd>
<dt><code class="code">GNUTLS_MAC_SHA384</code></dt>
<dd><p>HMAC-SHA-384 algorithm.
</p></dd>
<dt><code class="code">GNUTLS_MAC_SHA512</code></dt>
<dd><p>HMAC-SHA-512 algorithm.
</p></dd>
<dt><code class="code">GNUTLS_MAC_SHA224</code></dt>
<dd><p>HMAC-SHA-224 algorithm.
</p></dd>
<dt><code class="code">GNUTLS_MAC_SHA3_224</code></dt>
<dd><p>Reserved; unimplemented.
</p></dd>
<dt><code class="code">GNUTLS_MAC_SHA3_256</code></dt>
<dd><p>Reserved; unimplemented.
</p></dd>
<dt><code class="code">GNUTLS_MAC_SHA3_384</code></dt>
<dd><p>Reserved; unimplemented.
</p></dd>
<dt><code class="code">GNUTLS_MAC_SHA3_512</code></dt>
<dd><p>Reserved; unimplemented.
</p></dd>
<dt><code class="code">GNUTLS_MAC_MD5_SHA1</code></dt>
<dd><p>Combined MD5+SHA1 MAC placeholder.
</p></dd>
<dt><code class="code">GNUTLS_MAC_GOSTR_94</code></dt>
<dd><p>HMAC GOST R 34.11-94 algorithm.
</p></dd>
<dt><code class="code">GNUTLS_MAC_STREEBOG_256</code></dt>
<dd><p>HMAC GOST R 34.11-2001 (Streebog) algorithm, 256 bit.
</p></dd>
<dt><code class="code">GNUTLS_MAC_STREEBOG_512</code></dt>
<dd><p>HMAC GOST R 34.11-2001 (Streebog) algorithm, 512 bit.
</p></dd>
<dt><code class="code">GNUTLS_MAC_AEAD</code></dt>
<dd><p>MAC implicit through AEAD cipher.
</p></dd>
<dt><code class="code">GNUTLS_MAC_UMAC_96</code></dt>
<dd><p>The UMAC-96 MAC algorithm (requires nonce).
</p></dd>
<dt><code class="code">GNUTLS_MAC_UMAC_128</code></dt>
<dd><p>The UMAC-128 MAC algorithm (requires nonce).
</p></dd>
<dt><code class="code">GNUTLS_MAC_AES_CMAC_128</code></dt>
<dd><p>The AES-CMAC-128 MAC algorithm.
</p></dd>
<dt><code class="code">GNUTLS_MAC_AES_CMAC_256</code></dt>
<dd><p>The AES-CMAC-256 MAC algorithm.
</p></dd>
<dt><code class="code">GNUTLS_MAC_AES_GMAC_128</code></dt>
<dd><p>The AES-GMAC-128 MAC algorithm (requires nonce).
</p></dd>
<dt><code class="code">GNUTLS_MAC_AES_GMAC_192</code></dt>
<dd><p>The AES-GMAC-192 MAC algorithm (requires nonce).
</p></dd>
<dt><code class="code">GNUTLS_MAC_AES_GMAC_256</code></dt>
<dd><p>The AES-GMAC-256 MAC algorithm (requires nonce).
</p></dd>
<dt><code class="code">GNUTLS_MAC_GOST28147_TC26Z_IMIT</code></dt>
<dd><p>The GOST 28147-89 working in IMIT mode with TC26 Z S-box.
</p></dd>
<dt><code class="code">GNUTLS_MAC_SHAKE_128</code></dt>
<dd><p>The SHAKE128 extendable output function.
</p></dd>
<dt><code class="code">GNUTLS_MAC_SHAKE_256</code></dt>
<dd><p>The SHAKE256 extendable output function.
</p></dd>
<dt><code class="code">GNUTLS_MAC_MAGMA_OMAC</code></dt>
<dd><p>GOST R 34.12-2015 (Magma) in OMAC (CMAC) mode.
</p></dd>
<dt><code class="code">GNUTLS_MAC_KUZNYECHIK_OMAC</code></dt>
<dd><p>GOST R 34.12-2015 (Kuznyechik) in OMAC (CMAC) mode.
</p></dd>
<dt><code class="code">GNUTLS_MAC_PBMAC1</code></dt>
<dd><p>&ndash; undescribed &ndash;
</p></dd>
</dl>
<div class="caption"><p><strong class="strong">Figure 9.3: </strong>The supported MAC and HMAC algorithms.</p></div></div>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fhmac_005finit">gnutls_hmac_init</a> (gnutls_hmac_hd_t * <var class="var">dig</var>, gnutls_mac_algorithm_t <var class="var">algorithm</var>, const void * <var class="var">key</var>, size_t <var class="var">keylen</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fhmac">gnutls_hmac</a> (gnutls_hmac_hd_t <var class="var">handle</var>, const void * <var class="var">ptext</var>, size_t <var class="var">ptext_len</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fhmac_005foutput">gnutls_hmac_output</a> (gnutls_hmac_hd_t <var class="var">handle</var>, void * <var class="var">digest</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fhmac_005fdeinit">gnutls_hmac_deinit</a> (gnutls_hmac_hd_t <var class="var">handle</var>, void * <var class="var">digest</var>)</code></dt>
<dt><code class="code"><var class="var">unsigned</var> <a class="ref" href="#gnutls_005fhmac_005fget_005flen">gnutls_hmac_get_len</a> (gnutls_mac_algorithm_t <var class="var">algorithm</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fhmac_005ffast">gnutls_hmac_fast</a> (gnutls_mac_algorithm_t <var class="var">algorithm</var>, const void * <var class="var">key</var>, size_t <var class="var">keylen</var>, const void * <var class="var">ptext</var>, size_t <var class="var">ptext_len</var>, void * <var class="var">digest</var>)</code></dt>
</dl>

<p>The available functions to access hash functions are shown below. The supported hash functions
are shown in <a class="ref" href="#gnutls_005fdigest_005falgorithm_005ft">Figure 9.4</a>.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fhash_005finit">gnutls_hash_init</a> (gnutls_hash_hd_t * <var class="var">dig</var>, gnutls_digest_algorithm_t <var class="var">algorithm</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fhash">gnutls_hash</a> (gnutls_hash_hd_t <var class="var">handle</var>, const void * <var class="var">ptext</var>, size_t <var class="var">ptext_len</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fhash_005foutput">gnutls_hash_output</a> (gnutls_hash_hd_t <var class="var">handle</var>, void * <var class="var">digest</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005fhash_005fdeinit">gnutls_hash_deinit</a> (gnutls_hash_hd_t <var class="var">handle</var>, void * <var class="var">digest</var>)</code></dt>
<dt><code class="code"><var class="var">unsigned</var> <a class="ref" href="#gnutls_005fhash_005fget_005flen">gnutls_hash_get_len</a> (gnutls_digest_algorithm_t <var class="var">algorithm</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005fhash_005ffast">gnutls_hash_fast</a> (gnutls_digest_algorithm_t <var class="var">algorithm</var>, const void * <var class="var">ptext</var>, size_t <var class="var">ptext_len</var>, void * <var class="var">digest</var>)</code></dt>
</dl>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005ffingerprint">gnutls_fingerprint</a> (gnutls_digest_algorithm_t <var class="var">algo</var>, const gnutls_datum_t * <var class="var">data</var>, void * <var class="var">result</var>, size_t * <var class="var">result_size</var>)</code></dt>
</dl>

<div class="float" id="gnutls_005fdigest_005falgorithm_005ft">


<dl class="table">
<dt><code class="code">GNUTLS_DIG_UNKNOWN</code></dt>
<dd><p>Unknown hash algorithm.
</p></dd>
<dt><code class="code">GNUTLS_DIG_NULL</code></dt>
<dd><p>NULL hash algorithm (empty output).
</p></dd>
<dt><code class="code">GNUTLS_DIG_MD5</code></dt>
<dd><p>MD5 algorithm.
</p></dd>
<dt><code class="code">GNUTLS_DIG_SHA1</code></dt>
<dd><p>SHA-1 algorithm.
</p></dd>
<dt><code class="code">GNUTLS_DIG_RMD160</code></dt>
<dd><p>RMD160 algorithm.
</p></dd>
<dt><code class="code">GNUTLS_DIG_MD2</code></dt>
<dd><p>MD2 algorithm.
</p></dd>
<dt><code class="code">GNUTLS_DIG_SHA256</code></dt>
<dd><p>SHA-256 algorithm.
</p></dd>
<dt><code class="code">GNUTLS_DIG_SHA384</code></dt>
<dd><p>SHA-384 algorithm.
</p></dd>
<dt><code class="code">GNUTLS_DIG_SHA512</code></dt>
<dd><p>SHA-512 algorithm.
</p></dd>
<dt><code class="code">GNUTLS_DIG_SHA224</code></dt>
<dd><p>SHA-224 algorithm.
</p></dd>
<dt><code class="code">GNUTLS_DIG_SHA3_224</code></dt>
<dd><p>SHA3-224 algorithm.
</p></dd>
<dt><code class="code">GNUTLS_DIG_SHA3_256</code></dt>
<dd><p>SHA3-256 algorithm.
</p></dd>
<dt><code class="code">GNUTLS_DIG_SHA3_384</code></dt>
<dd><p>SHA3-384 algorithm.
</p></dd>
<dt><code class="code">GNUTLS_DIG_SHA3_512</code></dt>
<dd><p>SHA3-512 algorithm.
</p></dd>
<dt><code class="code">GNUTLS_DIG_MD5_SHA1</code></dt>
<dd><p>Combined MD5+SHA1 algorithm.
</p></dd>
<dt><code class="code">GNUTLS_DIG_GOSTR_94</code></dt>
<dd><p>GOST R 34.11-94 algorithm.
</p></dd>
<dt><code class="code">GNUTLS_DIG_STREEBOG_256</code></dt>
<dd><p>GOST R 34.11-2001 (Streebog) algorithm, 256 bit.
</p></dd>
<dt><code class="code">GNUTLS_DIG_STREEBOG_512</code></dt>
<dd><p>GOST R 34.11-2001 (Streebog) algorithm, 512 bit.
</p></dd>
<dt><code class="code">GNUTLS_DIG_SHAKE_128</code></dt>
<dd><p>The SHAKE128 extendable output function.
</p></dd>
<dt><code class="code">GNUTLS_DIG_SHAKE_256</code></dt>
<dd><p>The SHAKE256 extendable output function.
</p></dd>
</dl>
<div class="caption"><p><strong class="strong">Figure 9.4: </strong>The supported hash algorithms.</p></div></div>
<hr>
</div>
<div class="section-level-extent" id="Random-number-generation">
<div class="nav-panel">
<p>
Next: <a href="#Overriding-algorithms" accesskey="n" rel="next">Overriding algorithms</a>, Previous: <a href="#Hash-and-MAC-functions" accesskey="p" rel="prev">Hash and MAC functions</a>, Up: <a href="#Using-GnuTLS-as-a-cryptographic-library" accesskey="u" rel="up">Using GnuTLS as a cryptographic library</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Random-number-generation-1"><span>9.5 Random number generation<a class="copiable-link" href="#Random-number-generation-1"> &para;</a></span></h3>
<a class="index-entry-id" id="index-random-numbers"></a>

<p>Access to the random number generator is provided using the <a class="ref" href="#gnutls_005frnd">gnutls_rnd</a>
function. It allows obtaining random data of various levels.
</p>
<div class="float" id="gnutls_005frnd_005flevel_005ft">


<dl class="table">
<dt><code class="code">GNUTLS_RND_NONCE</code></dt>
<dd><p>Non-predictable random number.  Fatal in parts
of session if broken, i.e., vulnerable to statistical analysis.
</p></dd>
<dt><code class="code">GNUTLS_RND_RANDOM</code></dt>
<dd><p>Pseudo-random cryptographic random number.
Fatal in session if broken. Example use: temporal keys.
</p></dd>
<dt><code class="code">GNUTLS_RND_KEY</code></dt>
<dd><p>Fatal in many sessions if broken. Example use:
Long-term keys.
</p></dd>
</dl>
<div class="caption"><p><strong class="strong">Figure 9.5: </strong>The random number levels.</p></div></div>



<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frnd"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_rnd</strong> <code class="def-code-arguments">(gnutls_rnd_level_t <var class="var">level</var>, void * <var class="var">data</var>, size_t <var class="var">len</var>)</code><a class="copiable-link" href="#index-gnutls_005frnd"> &para;</a></span></dt>
<dd><p><var class="var">level</var>: a security level
</p>
<p><var class="var">data</var>: place to store random bytes
</p>
<p><var class="var">len</var>: The requested size
</p>
<p>This function will generate random data and store it to output
buffer. The value of  <code class="code">level</code> should be one of <code class="code">GNUTLS_RND_NONCE</code> ,
<code class="code">GNUTLS_RND_RANDOM</code>  and <code class="code">GNUTLS_RND_KEY</code> . See the manual and
<code class="code">gnutls_rnd_level_t</code>  for detailed information.
</p>
<p>This function is thread-safe and also fork-safe.
</p>
<p><strong class="strong">Returns:</strong> Zero on success, or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<p>See <a class="ref" href="#Random-Number-Generators_002dinternals">Random Number Generators</a> for more information
on the random number generator operation.
</p>
<hr>
</div>
<div class="section-level-extent" id="Overriding-algorithms">
<div class="nav-panel">
<p>
Previous: <a href="#Random-number-generation" accesskey="p" rel="prev">Random number generation</a>, Up: <a href="#Using-GnuTLS-as-a-cryptographic-library" accesskey="u" rel="up">Using GnuTLS as a cryptographic library</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Overriding-algorithms-1"><span>9.6 Overriding algorithms<a class="copiable-link" href="#Overriding-algorithms-1"> &para;</a></span></h3>
<a class="index-entry-id" id="index-overriding-algorithms"></a>

<p>In systems which provide a hardware accelerated cipher implementation
that is not directly supported by GnuTLS, it is possible to utilize it.
There are functions which allow overriding the default cipher, digest and MAC
implementations. Those are described below.
</p>
<p>To override public key operations see <a class="ref" href="#Abstract-private-keys">Private keys</a>.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcrypto_005fregister_005fcipher"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_crypto_register_cipher</strong> <code class="def-code-arguments">(gnutls_cipher_algorithm_t <var class="var">algorithm</var>, int <var class="var">priority</var>, gnutls_cipher_init_func <var class="var">init</var>, gnutls_cipher_setkey_func <var class="var">setkey</var>, gnutls_cipher_setiv_func <var class="var">setiv</var>, gnutls_cipher_encrypt_func <var class="var">encrypt</var>, gnutls_cipher_decrypt_func <var class="var">decrypt</var>, gnutls_cipher_deinit_func <var class="var">deinit</var>)</code><a class="copiable-link" href="#index-gnutls_005fcrypto_005fregister_005fcipher"> &para;</a></span></dt>
<dd><p><var class="var">algorithm</var>: is the gnutls algorithm identifier
</p>
<p><var class="var">priority</var>: is the priority of the algorithm
</p>
<p><var class="var">init</var>: A function which initializes the cipher
</p>
<p><var class="var">setkey</var>: A function which sets the key of the cipher
</p>
<p><var class="var">setiv</var>: A function which sets the nonce/IV of the cipher (non-AEAD)
</p>
<p><var class="var">encrypt</var>: A function which performs encryption (non-AEAD)
</p>
<p><var class="var">decrypt</var>: A function which performs decryption (non-AEAD)
</p>
<p><var class="var">deinit</var>: A function which deinitializes the cipher
</p>
<p>This function will register a cipher algorithm to be used by
gnutls.  Any algorithm registered will override the included
algorithms and by convention kernel implemented algorithms have
priority of 90 and CPU-assisted of 80.  The algorithm with the lowest priority will be
used by gnutls.
</p>
<p>In the case the registered init or setkey functions return <code class="code">GNUTLS_E_NEED_FALLBACK</code> ,
GnuTLS will attempt to use the next in priority registered cipher.
</p>
<p>The functions which are marked as non-AEAD they are not required when
registering a cipher to be used with the new AEAD API introduced in
GnuTLS 3.4.0. Internally GnuTLS uses the new AEAD API.
</p>
<p><strong class="strong">Deprecated:</strong> since 3.7.0 it is no longer possible to override cipher implementation
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcrypto_005fregister_005faead_005fcipher"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_crypto_register_aead_cipher</strong> <code class="def-code-arguments">(gnutls_cipher_algorithm_t <var class="var">algorithm</var>, int <var class="var">priority</var>, gnutls_cipher_init_func <var class="var">init</var>, gnutls_cipher_setkey_func <var class="var">setkey</var>, gnutls_cipher_aead_encrypt_func <var class="var">aead_encrypt</var>, gnutls_cipher_aead_decrypt_func <var class="var">aead_decrypt</var>, gnutls_cipher_deinit_func <var class="var">deinit</var>)</code><a class="copiable-link" href="#index-gnutls_005fcrypto_005fregister_005faead_005fcipher"> &para;</a></span></dt>
<dd><p><var class="var">algorithm</var>: is the gnutls AEAD cipher identifier
</p>
<p><var class="var">priority</var>: is the priority of the algorithm
</p>
<p><var class="var">init</var>: A function which initializes the cipher
</p>
<p><var class="var">setkey</var>: A function which sets the key of the cipher
</p>
<p><var class="var">aead_encrypt</var>: Perform the AEAD encryption
</p>
<p><var class="var">aead_decrypt</var>: Perform the AEAD decryption
</p>
<p><var class="var">deinit</var>: A function which deinitializes the cipher
</p>
<p>This function will register a cipher algorithm to be used by
gnutls.  Any algorithm registered will override the included
algorithms and by convention kernel implemented algorithms have
priority of 90 and CPU-assisted of 80.  The algorithm with the lowest priority will be
used by gnutls.
</p>
<p>In the case the registered init or setkey functions return <code class="code">GNUTLS_E_NEED_FALLBACK</code> ,
GnuTLS will attempt to use the next in priority registered cipher.
</p>
<p>The functions registered will be used with the new AEAD API introduced in
GnuTLS 3.4.0. Internally GnuTLS uses the new AEAD API.
</p>
<p><strong class="strong">Deprecated:</strong> since 3.7.0 it is no longer possible to override cipher implementation
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcrypto_005fregister_005fmac"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_crypto_register_mac</strong> <code class="def-code-arguments">(gnutls_mac_algorithm_t <var class="var">algorithm</var>, int <var class="var">priority</var>, gnutls_mac_init_func <var class="var">init</var>, gnutls_mac_setkey_func <var class="var">setkey</var>, gnutls_mac_setnonce_func <var class="var">setnonce</var>, gnutls_mac_hash_func <var class="var">hash</var>, gnutls_mac_output_func <var class="var">output</var>, gnutls_mac_deinit_func <var class="var">deinit</var>, gnutls_mac_fast_func <var class="var">hash_fast</var>)</code><a class="copiable-link" href="#index-gnutls_005fcrypto_005fregister_005fmac"> &para;</a></span></dt>
<dd><p><var class="var">algorithm</var>: is the gnutls MAC identifier
</p>
<p><var class="var">priority</var>: is the priority of the algorithm
</p>
<p><var class="var">init</var>: A function which initializes the MAC
</p>
<p><var class="var">setkey</var>: A function which sets the key of the MAC
</p>
<p><var class="var">setnonce</var>: A function which sets the nonce for the mac (may be <code class="code">NULL</code>  for common MAC algorithms)
</p>
<p><var class="var">hash</var>: Perform the hash operation
</p>
<p><var class="var">output</var>: Provide the output of the MAC
</p>
<p><var class="var">deinit</var>: A function which deinitializes the MAC
</p>
<p><var class="var">hash_fast</var>: Perform the MAC operation in one go
</p>
<p>This function will register a MAC algorithm to be used by gnutls.
Any algorithm registered will override the included algorithms and
by convention kernel implemented algorithms have priority of 90
and CPU-assisted of 80.
The algorithm with the lowest priority will be used by gnutls.
</p>
<p><strong class="strong">Deprecated:</strong> since 3.7.0 it is no longer possible to override cipher implementation
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcrypto_005fregister_005fdigest"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_crypto_register_digest</strong> <code class="def-code-arguments">(gnutls_digest_algorithm_t <var class="var">algorithm</var>, int <var class="var">priority</var>, gnutls_digest_init_func <var class="var">init</var>, gnutls_digest_hash_func <var class="var">hash</var>, gnutls_digest_output_func <var class="var">output</var>, gnutls_digest_deinit_func <var class="var">deinit</var>, gnutls_digest_fast_func <var class="var">hash_fast</var>)</code><a class="copiable-link" href="#index-gnutls_005fcrypto_005fregister_005fdigest"> &para;</a></span></dt>
<dd><p><var class="var">algorithm</var>: is the gnutls digest identifier
</p>
<p><var class="var">priority</var>: is the priority of the algorithm
</p>
<p><var class="var">init</var>: A function which initializes the digest
</p>
<p><var class="var">hash</var>: Perform the hash operation
</p>
<p><var class="var">output</var>: Provide the output of the digest
</p>
<p><var class="var">deinit</var>: A function which deinitializes the digest
</p>
<p><var class="var">hash_fast</var>: Perform the digest operation in one go
</p>
<p>This function will register a digest algorithm to be used by gnutls.
Any algorithm registered will override the included algorithms and
by convention kernel implemented algorithms have priority of 90
and CPU-assisted of 80.
The algorithm with the lowest priority will be used by gnutls.
</p>
<p><strong class="strong">Deprecated:</strong> since 3.7.0 it is no longer possible to override cipher implementation
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<hr>
</div>
</div>
<div class="chapter-level-extent" id="Other-included-programs">
<div class="nav-panel">
<p>
Next: <a href="#Internal-architecture-of-GnuTLS" accesskey="n" rel="next">Internal Architecture of GnuTLS</a>, Previous: <a href="#Using-GnuTLS-as-a-cryptographic-library" accesskey="p" rel="prev">Using GnuTLS as a cryptographic library</a>, Up: <a href="#Top" accesskey="u" rel="up">GnuTLS</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h2 class="chapter" id="Other-included-programs-1"><span>10 Other included programs<a class="copiable-link" href="#Other-included-programs-1"> &para;</a></span></h2>

<p>Included with <abbr class="acronym">GnuTLS</abbr> are also a few command line tools that
let you use the library for common tasks without writing an
application.  The applications are discussed in this chapter.
</p>

<hr>
<a class="node" id="gnutls_002dcli-Invocation"></a><div class="nav-panel">
<p>
[<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="heading" id="Invoking-gnutls_002dcli"><span>Invoking gnutls-cli<a class="copiable-link" href="#Invoking-gnutls_002dcli"> &para;</a></span></h3>
<a class="index-entry-id" id="index-gnutls_002dcli"></a>

<p>Simple client program to set up a TLS connection to some other computer. 
It sets up a TLS connection and forwards data from the standard input to the secured socket and vice versa.
</p>
<a class="anchor" id="gnutls_002dcli-usage"></a><h4 class="subheading" id="gnutls_002dcli-help_002fusage-_0028_002d_003f_0029"><span>gnutls-cli help/usage (<samp class="option">-?</samp>)<a class="copiable-link" href="#gnutls_002dcli-help_002fusage-_0028_002d_003f_0029"> &para;</a></span></h4>
<a class="index-entry-id" id="index-gnutls_002dcli-help"></a>

<p>The text printed is the same whether selected with the <code class="code">help</code> option
(<samp class="option">--help</samp>) or the <code class="code">more-help</code> option (<samp class="option">--more-help</samp>).  <code class="code">more-help</code> will print
the usage text by passing it through a pager program.
<code class="code">more-help</code> is disabled on platforms without a working
<code class="code">fork(2)</code> function.  The <code class="code">PAGER</code> environment variable is
used to select the program, defaulting to <samp class="file">more</samp>.  Both will exit
with a status code of 0.
</p>
<div class="example">
<pre class="example-preformatted">gnutls-cli - GnuTLS client
Usage:  gnutls-cli [ -&lt;flag&gt; [&lt;val&gt;] | --&lt;name&gt;[{=| }&lt;val&gt;] ]... [hostname]

None:

   -d, --debug=num            Enable debugging
				- it must be in the range:
				  0 to 9999
   -V, --verbose              More verbose output
       --tofu                 Enable trust on first use authentication
       --strict-tofu          Fail to connect if a certificate is unknown or a known certificate has changed
       --dane                 Enable DANE certificate verification (DNSSEC)
       --local-dns            Use the local DNS server for DNSSEC resolving
       --ca-verification      Enable CA certificate verification
				- enabled by default
				- disabled as '--no-ca-verification'
       --ocsp                 Enable OCSP certificate verification
   -r, --resume               Establish a session and resume
       --earlydata=str        Send early data on resumption from the specified file
   -e, --rehandshake          Establish a session and rehandshake
       --sni-hostname=str     Server's hostname for server name indication extension
       --verify-hostname=str  Server's hostname to use for validation
   -s, --starttls             Connect, establish a plain session and start TLS
       --app-proto            an alias for the 'starttls-proto' option
       --starttls-proto=str   The application protocol to be used to obtain the server's certificate (https, ftp, smtp, imap, ldap, xmpp, lmtp, pop3, nntp, sieve, postgres)
				- prohibits the option 'starttls'
       --starttls-name=str    The hostname presented to the application protocol for STARTTLS (for smtp, xmpp, lmtp)
				- prohibits the option 'starttls'
				- requires the option 'starttls-proto'
   -u, --udp                  Use DTLS (datagram TLS) over UDP
       --mtu=num              Set MTU for datagram TLS
				- it must be in the range:
				  0 to 17000
       --crlf                 Send CR LF instead of LF
       --fastopen             Enable TCP Fast Open
       --x509fmtder           Use DER format for certificates to read from
       --print-cert           Print peer's certificate in PEM format
       --save-cert=str        Save the peer's certificate chain in the specified file in PEM format
       --save-ocsp=str        Save the peer's OCSP status response in the provided file
				- prohibits the option 'save-ocsp-multi'
       --save-ocsp-multi=str  Save all OCSP responses provided by the peer in this file
				- prohibits the option 'save-ocsp'
       --save-server-trace=str Save the server-side TLS message trace in the provided file
       --save-client-trace=str Save the client-side TLS message trace in the provided file
       --dh-bits=num          The minimum number of bits allowed for DH
       --priority=str         Priorities string
       --x509cafile=str       Certificate file or PKCS #11 URL to use
       --x509crlfile=file     CRL file to use
				- file must pre-exist
       --x509keyfile=str      X.509 key file or PKCS #11 URL to use
       --x509certfile=str     X.509 Certificate file or PKCS #11 URL to use
				- requires the option 'x509keyfile'
       --rawpkkeyfile=str     Private key file (PKCS #8 or PKCS #12) or PKCS #11 URL to use
       --rawpkfile=str        Raw public-key file to use
				- requires the option 'rawpkkeyfile'
       --srpusername=str      SRP username to use
       --srppasswd=str        SRP password to use
       --pskusername=str      PSK username to use
       --pskkey=str           PSK key (in hex) to use
   -p, --port=str             The port or service to connect to
       --insecure             Don't abort program if server certificate can't be validated
       --verify-allow-broken  Allow broken algorithms, such as MD5 for certificate verification
       --benchmark-ciphers    Benchmark individual ciphers
       --benchmark-tls-kx     Benchmark TLS key exchange methods
       --benchmark-tls-ciphers  Benchmark TLS ciphers
   -l, --list                 Print a list of the supported algorithms and modes
				- prohibits the option 'port'
       --priority-list        Print a list of the supported priority strings
       --noticket             Don't allow session tickets
       --srtp-profiles=str    Offer SRTP profiles
       --alpn=str             Application layer protocol
       --compress-cert=str    Compress certificate
   -b, --heartbeat            Activate heartbeat support
       --recordsize=num       The maximum record size to advertise
				- it must be in the range:
				  0 to 4096
       --disable-sni          Do not send a Server Name Indication (SNI)
       --single-key-share     Send a single key share under TLS1.3
       --post-handshake-auth  Enable post-handshake authentication under TLS1.3
       --inline-commands      Inline commands of the form ^&lt;cmd&gt;^
       --inline-commands-prefix=str Change the default delimiter for inline commands
       --provider=file        Specify the PKCS #11 provider library
				- file must pre-exist
       --fips140-mode         Reports the status of the FIPS140-2 mode in gnutls library
       --list-config          Reports the configuration of the library
       --logfile=str          Redirect informational messages to a specific file
       --keymatexport=str     Label used for exporting keying material
       --keymatexportsize=num Size of the exported keying material
       --waitresumption       Block waiting for the resumption data under TLS1.3
       --ca-auto-retrieve     Enable automatic retrieval of missing CA certificates
       --attime=str           Perform validation at the timestamp instead of the system time

Version, usage and configuration options:

   -v, --version[=arg]        output version information and exit
   -h, --help                 display extended usage information and exit
   -!, --more-help            extended usage information passed thru pager

Options are specified by doubled hyphens and their name or by a single
hyphen and the flag character.
Operands and options may be intermixed.  They will be reordered.

Simple client program to set up a TLS connection to some other computer. 
It sets up a TLS connection and forwards data from the standard input to the secured socket and vice versa.

Please send bug reports to:  &lt;bugs@gnutls.org&gt;

</pre></div>

<h4 class="subheading" id="debug-option-_0028_002dd_0029_002e"><span>debug option (-d).<a class="copiable-link" href="#debug-option-_0028_002dd_0029_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli-debug"></a>
<p>This is the &ldquo;enable debugging&rdquo; option.
This option takes a ArgumentType.NUMBER argument.
Specifies the debug level.
</p><h4 class="subheading" id="tofu-option_002e"><span>tofu option.<a class="copiable-link" href="#tofu-option_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli-tofu"></a>
<p>This is the &ldquo;enable trust on first use authentication&rdquo; option.
This option will, in addition to certificate authentication, perform authentication
based on previously seen public keys, a model similar to SSH authentication. Note that when tofu 
is specified (PKI) and DANE authentication will become advisory to assist the public key acceptance
process.
</p><h4 class="subheading" id="strict_002dtofu-option_002e"><span>strict-tofu option.<a class="copiable-link" href="#strict_002dtofu-option_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli-strict_002dtofu"></a>
<p>This is the &ldquo;fail to connect if a certificate is unknown or a known certificate has changed&rdquo; option.
This option will perform authentication as with option &ndash;tofu; however, no questions shall be asked whatsoever, neither to accept an unknown certificate nor a changed one.
</p><h4 class="subheading" id="dane-option_002e"><span>dane option.<a class="copiable-link" href="#dane-option_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli-dane"></a>
<p>This is the &ldquo;enable dane certificate verification (dnssec)&rdquo; option.
This option will, in addition to certificate authentication using 
the trusted CAs, verify the server certificates using on the DANE information
available via DNSSEC.
</p><h4 class="subheading" id="local_002ddns-option_002e"><span>local-dns option.<a class="copiable-link" href="#local_002ddns-option_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli-local_002ddns"></a>
<p>This is the &ldquo;use the local dns server for dnssec resolving&rdquo; option.
This option will use the local DNS server for DNSSEC.
This is disabled by default due to many servers not allowing DNSSEC.
</p><h4 class="subheading" id="ca_002dverification-option_002e"><span>ca-verification option.<a class="copiable-link" href="#ca_002dverification-option_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli-ca_002dverification"></a>
<p>This is the &ldquo;enable ca certificate verification&rdquo; option.
</p>
<p>This option has some usage constraints.  It:
</p><ul class="itemize mark-bullet">
<li>can be disabled with &ndash;no-ca-verification.
</li><li>It is enabled by default.
</li></ul>

<p>This option can be used to enable or disable CA certificate verification. It is to be used with the &ndash;dane or &ndash;tofu options.
</p><h4 class="subheading" id="ocsp-option_002e"><span>ocsp option.<a class="copiable-link" href="#ocsp-option_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli-ocsp"></a>
<p>This is the &ldquo;enable ocsp certificate verification&rdquo; option.
This option will enable verification of the peer&rsquo;s certificate using ocsp
</p><h4 class="subheading" id="resume-option-_0028_002dr_0029_002e"><span>resume option (-r).<a class="copiable-link" href="#resume-option-_0028_002dr_0029_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli-resume"></a>
<p>This is the &ldquo;establish a session and resume&rdquo; option.
Connect, establish a session, reconnect and resume.
</p><h4 class="subheading" id="rehandshake-option-_0028_002de_0029_002e"><span>rehandshake option (-e).<a class="copiable-link" href="#rehandshake-option-_0028_002de_0029_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli-rehandshake"></a>
<p>This is the &ldquo;establish a session and rehandshake&rdquo; option.
Connect, establish a session and rehandshake immediately.
</p><h4 class="subheading" id="sni_002dhostname-option_002e"><span>sni-hostname option.<a class="copiable-link" href="#sni_002dhostname-option_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli-sni_002dhostname"></a>
<p>This is the &ldquo;server&rsquo;s hostname for server name indication extension&rdquo; option.
This option takes a ArgumentType.STRING argument.
Set explicitly the server name used in the TLS server name indication extension. That is useful when testing with servers setup on different DNS name than the intended. If not specified, the provided hostname is used. Even with this option server certificate verification still uses the hostname passed on the main commandline. Use &ndash;verify-hostname to change this.
</p><h4 class="subheading" id="verify_002dhostname-option_002e"><span>verify-hostname option.<a class="copiable-link" href="#verify_002dhostname-option_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli-verify_002dhostname"></a>
<p>This is the &ldquo;server&rsquo;s hostname to use for validation&rdquo; option.
This option takes a ArgumentType.STRING argument.
Set explicitly the server name to be used when validating the server&rsquo;s certificate.
</p><h4 class="subheading" id="starttls-option-_0028_002ds_0029_002e"><span>starttls option (-s).<a class="copiable-link" href="#starttls-option-_0028_002ds_0029_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli-starttls"></a>
<p>This is the &ldquo;connect, establish a plain session and start tls&rdquo; option.
The TLS session will be initiated when EOF or a SIGALRM is received.
</p><h4 class="subheading" id="app_002dproto-option_002e"><span>app-proto option.<a class="copiable-link" href="#app_002dproto-option_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli-app_002dproto"></a>
<p>This is an alias for the <code class="code">starttls-proto</code> option,
see <a class="pxref" href="#gnutls_002dcli-starttls_002dproto">the starttls-proto option documentation</a>.
</p>
<h4 class="subheading" id="starttls_002dproto-option_002e"><span>starttls-proto option.<a class="copiable-link" href="#starttls_002dproto-option_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli-starttls_002dproto"></a>
<p>This is the &ldquo;the application protocol to be used to obtain the server&rsquo;s certificate (https, ftp, smtp, imap, ldap, xmpp, lmtp, pop3, nntp, sieve, postgres)&rdquo; option.
This option takes a ArgumentType.STRING argument.
</p>
<p>This option has some usage constraints.  It:
</p><ul class="itemize mark-bullet">
<li>must not appear in combination with any of the following options:
starttls.
</li></ul>

<p>Specify the application layer protocol for STARTTLS. If the protocol is supported, gnutls-cli will proceed to the TLS negotiation.
</p><h4 class="subheading" id="starttls_002dname-option_002e"><span>starttls-name option.<a class="copiable-link" href="#starttls_002dname-option_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli-starttls_002dname"></a>
<p>This is the &ldquo;the hostname presented to the application protocol for starttls (for smtp, xmpp, lmtp)&rdquo; option.
This option takes a ArgumentType.STRING argument.
</p>
<p>This option has some usage constraints.  It:
</p><ul class="itemize mark-bullet">
<li>must not appear in combination with any of the following options:
starttls.
</li><li>must appear in combination with the following options:
starttls-proto.
</li></ul>

<p>Specify the hostname presented to the application protocol for STARTTLS.
</p><h4 class="subheading" id="save_002docsp_002dmulti-option_002e"><span>save-ocsp-multi option.<a class="copiable-link" href="#save_002docsp_002dmulti-option_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli-save_002docsp_002dmulti"></a>
<p>This is the &ldquo;save all ocsp responses provided by the peer in this file&rdquo; option.
This option takes a ArgumentType.STRING argument.
</p>
<p>This option has some usage constraints.  It:
</p><ul class="itemize mark-bullet">
<li>must not appear in combination with any of the following options:
save-ocsp.
</li></ul>

<p>The file will contain a list of PEM encoded OCSP status responses if any were provided by the peer, starting with the one for the peer&rsquo;s server certificate.
</p><h4 class="subheading" id="dh_002dbits-option_002e"><span>dh-bits option.<a class="copiable-link" href="#dh_002dbits-option_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli-dh_002dbits"></a>
<p>This is the &ldquo;the minimum number of bits allowed for dh&rdquo; option.
This option takes a ArgumentType.NUMBER argument.
This option sets the minimum number of bits allowed for a Diffie-Hellman key exchange. You may want to lower the default value if the peer sends a weak prime and you get an connection error with unacceptable prime.
</p><h4 class="subheading" id="priority-option_002e"><span>priority option.<a class="copiable-link" href="#priority-option_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli-priority"></a>
<p>This is the &ldquo;priorities string&rdquo; option.
This option takes a ArgumentType.STRING argument.
TLS algorithms and protocols to enable. You can
use predefined sets of ciphersuites such as PERFORMANCE,
NORMAL, PFS, SECURE128, SECURE256. The default is NORMAL.
</p>
<p>Check  the  GnuTLS  manual  on  section  &ldquo;Priority strings&rdquo; for more
information on the allowed keywords
</p><h4 class="subheading" id="rawpkkeyfile-option_002e"><span>rawpkkeyfile option.<a class="copiable-link" href="#rawpkkeyfile-option_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli-rawpkkeyfile"></a>
<p>This is the &ldquo;private key file (pkcs #8 or pkcs #12) or pkcs #11 url to use&rdquo; option.
This option takes a ArgumentType.STRING argument.
In order to instruct the application to negotiate raw public keys one
must enable the respective certificate types via the priority strings (i.e. CTYPE-CLI-*
and CTYPE-SRV-* flags).
</p>
<p>Check  the  GnuTLS  manual  on  section  &ldquo;Priority strings&rdquo; for more
information on how to set certificate types.
</p><h4 class="subheading" id="rawpkfile-option_002e"><span>rawpkfile option.<a class="copiable-link" href="#rawpkfile-option_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli-rawpkfile"></a>
<p>This is the &ldquo;raw public-key file to use&rdquo; option.
This option takes a ArgumentType.STRING argument.
</p>
<p>This option has some usage constraints.  It:
</p><ul class="itemize mark-bullet">
<li>must appear in combination with the following options:
rawpkkeyfile.
</li></ul>

<p>In order to instruct the application to negotiate raw public keys one
must enable the respective certificate types via the priority strings (i.e. CTYPE-CLI-*
and CTYPE-SRV-* flags).
</p>
<p>Check  the  GnuTLS  manual  on  section  &ldquo;Priority strings&rdquo; for more
information on how to set certificate types.
</p><h4 class="subheading" id="ranges-option_002e"><span>ranges option.<a class="copiable-link" href="#ranges-option_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli-ranges"></a>
<p>This is the &ldquo;use length-hiding padding to prevent traffic analysis&rdquo; option.
When possible (e.g., when using CBC ciphersuites), use length-hiding padding to prevent traffic analysis.
</p>
<p><strong class="strong">NOTE</strong><strong class="strong">: THIS OPTION IS DEPRECATED</strong>
</p><h4 class="subheading" id="benchmark_002dciphers-option_002e"><span>benchmark-ciphers option.<a class="copiable-link" href="#benchmark_002dciphers-option_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli-benchmark_002dciphers"></a>
<p>This is the &ldquo;benchmark individual ciphers&rdquo; option.
By default the benchmarked ciphers will utilize any capabilities of the local CPU to improve performance. To test against the raw software implementation set the environment variable GNUTLS_CPUID_OVERRIDE to 0x1.
</p><h4 class="subheading" id="benchmark_002dtls_002dciphers-option_002e"><span>benchmark-tls-ciphers option.<a class="copiable-link" href="#benchmark_002dtls_002dciphers-option_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli-benchmark_002dtls_002dciphers"></a>
<p>This is the &ldquo;benchmark tls ciphers&rdquo; option.
By default the benchmarked ciphers will utilize any capabilities of the local CPU to improve performance. To test against the raw software implementation set the environment variable GNUTLS_CPUID_OVERRIDE to 0x1.
</p><h4 class="subheading" id="list-option-_0028_002dl_0029_002e"><span>list option (-l).<a class="copiable-link" href="#list-option-_0028_002dl_0029_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli-list"></a>
<p>This is the &ldquo;print a list of the supported algorithms and modes&rdquo; option.
</p>
<p>This option has some usage constraints.  It:
</p><ul class="itemize mark-bullet">
<li>must not appear in combination with any of the following options:
port.
</li></ul>

<p>Print a list of the supported algorithms and modes. If a priority string is given then only the enabled ciphersuites are shown.
</p><h4 class="subheading" id="priority_002dlist-option_002e"><span>priority-list option.<a class="copiable-link" href="#priority_002dlist-option_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli-priority_002dlist"></a>
<p>This is the &ldquo;print a list of the supported priority strings&rdquo; option.
Print a list of the supported priority strings. The ciphersuites corresponding to each priority string can be examined using -l -p.
</p><h4 class="subheading" id="noticket-option_002e"><span>noticket option.<a class="copiable-link" href="#noticket-option_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli-noticket"></a>
<p>This is the &ldquo;don&rsquo;t allow session tickets&rdquo; option.
Disable the request of receiving of session tickets under TLS1.2 or earlier
</p><h4 class="subheading" id="alpn-option_002e"><span>alpn option.<a class="copiable-link" href="#alpn-option_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli-alpn"></a>
<p>This is the &ldquo;application layer protocol&rdquo; option.
This option takes a ArgumentType.STRING argument.
This option will set and enable the Application Layer Protocol Negotiation  (ALPN) in the TLS protocol.
</p><h4 class="subheading" id="compress_002dcert-option_002e"><span>compress-cert option.<a class="copiable-link" href="#compress_002dcert-option_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli-compress_002dcert"></a>
<p>This is the &ldquo;compress certificate&rdquo; option.
This option takes a ArgumentType.STRING argument.
This option sets a supported compression method for certificate compression.
</p><h4 class="subheading" id="disable_002dextensions-option_002e"><span>disable-extensions option.<a class="copiable-link" href="#disable_002dextensions-option_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli-disable_002dextensions"></a>
<p>This is the &ldquo;disable all the tls extensions&rdquo; option.
This option disables all TLS extensions. Deprecated option. Use the priority string.
</p>
<p><strong class="strong">NOTE</strong><strong class="strong">: THIS OPTION IS DEPRECATED</strong>
</p><h4 class="subheading" id="single_002dkey_002dshare-option_002e"><span>single-key-share option.<a class="copiable-link" href="#single_002dkey_002dshare-option_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli-single_002dkey_002dshare"></a>
<p>This is the &ldquo;send a single key share under tls1.3&rdquo; option.
This option switches the default mode of sending multiple
key shares, to send a single one (the top one).
</p><h4 class="subheading" id="post_002dhandshake_002dauth-option_002e"><span>post-handshake-auth option.<a class="copiable-link" href="#post_002dhandshake_002dauth-option_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli-post_002dhandshake_002dauth"></a>
<p>This is the &ldquo;enable post-handshake authentication under tls1.3&rdquo; option.
This option enables post-handshake authentication when under TLS1.3.
</p><h4 class="subheading" id="inline_002dcommands-option_002e"><span>inline-commands option.<a class="copiable-link" href="#inline_002dcommands-option_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli-inline_002dcommands"></a>
<p>This is the &ldquo;inline commands of the form ^&lt;cmd&gt;^&rdquo; option.
Enable inline commands of the form ^&lt;cmd&gt;^. The inline commands are expected to be in a line by themselves. The available commands are: resume, rekey1 (local rekey), rekey (rekey on both peers) and renegotiate.
</p><h4 class="subheading" id="inline_002dcommands_002dprefix-option_002e"><span>inline-commands-prefix option.<a class="copiable-link" href="#inline_002dcommands_002dprefix-option_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli-inline_002dcommands_002dprefix"></a>
<p>This is the &ldquo;change the default delimiter for inline commands&rdquo; option.
This option takes a ArgumentType.STRING argument.
Change the default delimiter (^) used for inline commands. The delimiter is expected to be a single US-ASCII character (octets 0 - 127). This option is only relevant if inline commands are enabled via the inline-commands option
</p><h4 class="subheading" id="provider-option_002e"><span>provider option.<a class="copiable-link" href="#provider-option_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli-provider"></a>
<p>This is the &ldquo;specify the pkcs #11 provider library&rdquo; option.
This option takes a ArgumentType.FILE argument.
This will override the default options in /etc/gnutls/pkcs11.conf
</p><h4 class="subheading" id="logfile-option_002e"><span>logfile option.<a class="copiable-link" href="#logfile-option_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli-logfile"></a>
<p>This is the &ldquo;redirect informational messages to a specific file&rdquo; option.
This option takes a ArgumentType.STRING argument.
Redirect informational messages to a specific file. The file may be /dev/null also to make the gnutls client quiet to use it in piped server connections where only the server communication may appear on stdout.
</p><h4 class="subheading" id="waitresumption-option_002e"><span>waitresumption option.<a class="copiable-link" href="#waitresumption-option_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli-waitresumption"></a>
<p>This is the &ldquo;block waiting for the resumption data under tls1.3&rdquo; option.
This option makes the client to block waiting for the resumption data under TLS1.3. The option has effect only when &ndash;resume is provided.
</p><h4 class="subheading" id="ca_002dauto_002dretrieve-option_002e"><span>ca-auto-retrieve option.<a class="copiable-link" href="#ca_002dauto_002dretrieve-option_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli-ca_002dauto_002dretrieve"></a>
<p>This is the &ldquo;enable automatic retrieval of missing ca certificates&rdquo; option.
This option enables the client to automatically retrieve the missing intermediate CA certificates in the certificate chain, based on the Authority Information Access (AIA) extension.
</p><h4 class="subheading" id="attime-option_002e"><span>attime option.<a class="copiable-link" href="#attime-option_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli-attime"></a>
<p>This is the &ldquo;perform validation at the timestamp instead of the system time&rdquo; option.
This option takes a ArgumentType.STRING argument <samp class="file">timestamp</samp>.
timestamp is an instance in time encoded as Unix time or in a human
 readable timestring such as &quot;29 Feb 2004&quot;, &quot;2004-02-29&quot;.
Full documentation available at 
&lt;https://www.gnu.org/software/coreutils/manual/html_node/Date-input-formats.html&gt;
or locally via info &rsquo;(coreutils) date invocation&rsquo;.
</p><h4 class="subheading" id="version-option-_0028_002dv_0029_002e"><span>version option (-v).<a class="copiable-link" href="#version-option-_0028_002dv_0029_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli-version"></a>
<p>This is the &ldquo;output version information and exit&rdquo; option.
This option takes a ArgumentType.KEYWORD argument.
Output version of program and exit.  The default mode is &lsquo;v&rsquo;, a simple
version.  The &lsquo;c&rsquo; mode will print copyright information and &lsquo;n&rsquo; will
print the full copyright notice.
</p><h4 class="subheading" id="help-option-_0028_002dh_0029_002e"><span>help option (-h).<a class="copiable-link" href="#help-option-_0028_002dh_0029_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli-help"></a>
<p>This is the &ldquo;display extended usage information and exit&rdquo; option.
Display usage information and exit.
</p><h4 class="subheading" id="more_002dhelp-option-_0028_002d_0021_0029_002e"><span>more-help option (-!).<a class="copiable-link" href="#more_002dhelp-option-_0028_002d_0021_0029_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli-more_002dhelp"></a>
<p>This is the &ldquo;extended usage information passed thru pager&rdquo; option.
Pass the extended usage information through a pager.
<a class="anchor" id="gnutls_002dcli-exit-status"></a></p><h4 class="subheading" id="gnutls_002dcli-exit-status-1"><span>gnutls-cli exit status<a class="copiable-link" href="#gnutls_002dcli-exit-status-1"> &para;</a></span></h4>

<p>One of the following exit values will be returned:
</p><dl class="table">
<dt>&lsquo;<samp class="samp">0 (EXIT_SUCCESS)</samp>&rsquo;</dt>
<dd><p>Successful program execution.
</p></dd>
<dt>&lsquo;<samp class="samp">1 (EXIT_FAILURE)</samp>&rsquo;</dt>
<dd><p>The operation failed or the command syntax was not valid.
</p></dd>
</dl>
<a class="anchor" id="gnutls_002dcli-See-Also"></a><h4 class="subsubheading" id="gnutls_002dcli-See-Also-1"><span>gnutls-cli See Also<a class="copiable-link" href="#gnutls_002dcli-See-Also-1"> &para;</a></span></h4>
<p>gnutls-cli-debug(1), gnutls-serv(1)
<a class="anchor" id="gnutls_002dcli-Examples"></a></p><h4 class="subsubheading" id="gnutls_002dcli-Examples-1"><span>gnutls-cli Examples<a class="copiable-link" href="#gnutls_002dcli-Examples-1"> &para;</a></span></h4>
<h4 class="subheading" id="Connecting-using-PSK-authentication"><span>Connecting using PSK authentication<a class="copiable-link" href="#Connecting-using-PSK-authentication"> &para;</a></span></h4>
<p>To connect to a server using PSK authentication, you need to enable the choice of PSK by using a cipher priority parameter such as in the example below. 
</p><div class="example">
<pre class="example-preformatted">$ ./gnutls-cli -p 5556 localhost --pskusername psk_identity \
    --pskkey 88f3824b3e5659f52d00e959bacab954b6540344 \
    --priority NORMAL:-KX-ALL:+ECDHE-PSK:+DHE-PSK:+PSK
Resolving 'localhost'...
Connecting to '127.0.0.1:5556'...
- PSK authentication.
- Version: TLS1.1
- Key Exchange: PSK
- Cipher: AES-128-CBC
- MAC: SHA1
- Compression: NULL
- Handshake was completed
    
- Simple Client Mode:
</pre></div>
<p>By keeping the &ndash;pskusername parameter and removing the &ndash;pskkey parameter, it will query only for the password during the handshake.
</p>
<h4 class="subheading" id="Connecting-using-raw-public_002dkey-authentication"><span>Connecting using raw public-key authentication<a class="copiable-link" href="#Connecting-using-raw-public_002dkey-authentication"> &para;</a></span></h4>
<p>To connect to a server using raw public-key authentication, you need to enable the option to negotiate raw public-keys via the priority strings such as in the example below. 
</p><div class="example">
<pre class="example-preformatted">$ ./gnutls-cli -p 5556 localhost --priority NORMAL:-CTYPE-CLI-ALL:+CTYPE-CLI-RAWPK \
    --rawpkkeyfile cli.key.pem \
    --rawpkfile cli.rawpk.pem
Processed 1 client raw public key pair...
Resolving 'localhost'...
Connecting to '127.0.0.1:5556'...
- Successfully sent 1 certificate(s) to server.
- Server has requested a certificate.
- Certificate type: X.509
- Got a certificate list of 1 certificates.
- Certificate[0] info:
 - skipped
- Description: (TLS1.3-Raw Public Key-X.509)-(ECDHE-SECP256R1)-(RSA-PSS-RSAE-SHA256)-(AES-256-GCM)
- Options:
- Handshake was completed
    
- Simple Client Mode:
</pre></div>

<h4 class="subheading" id="Connecting-to-STARTTLS-services"><span>Connecting to STARTTLS services<a class="copiable-link" href="#Connecting-to-STARTTLS-services"> &para;</a></span></h4>

<p>You could also use the client to connect to services with starttls capability.
</p><div class="example">
<pre class="example-preformatted">$ gnutls-cli --starttls-proto smtp --port 25 localhost
</pre></div>

<h4 class="subheading" id="Listing-ciphersuites-in-a-priority-string"><span>Listing ciphersuites in a priority string<a class="copiable-link" href="#Listing-ciphersuites-in-a-priority-string"> &para;</a></span></h4>
<p>To list the ciphersuites in a priority string:
</p><div class="example">
<pre class="example-preformatted">$ ./gnutls-cli --priority SECURE192 -l
Cipher suites for SECURE192
TLS_ECDHE_ECDSA_AES_256_CBC_SHA384         0xc0, 0x24	TLS1.2
TLS_ECDHE_ECDSA_AES_256_GCM_SHA384         0xc0, 0x2e	TLS1.2
TLS_ECDHE_RSA_AES_256_GCM_SHA384           0xc0, 0x30	TLS1.2
TLS_DHE_RSA_AES_256_CBC_SHA256             0x00, 0x6b	TLS1.2
TLS_DHE_DSS_AES_256_CBC_SHA256             0x00, 0x6a	TLS1.2
TLS_RSA_AES_256_CBC_SHA256                 0x00, 0x3d	TLS1.2

Certificate types: CTYPE-X.509
Protocols: VERS-TLS1.2, VERS-TLS1.1, VERS-TLS1.0, VERS-SSL3.0, VERS-DTLS1.0
Compression: COMP-NULL
Elliptic curves: CURVE-SECP384R1, CURVE-SECP521R1
PK-signatures: SIGN-RSA-SHA384, SIGN-ECDSA-SHA384, SIGN-RSA-SHA512, SIGN-ECDSA-SHA512
</pre></div>

<h4 class="subheading" id="Connecting-using-a-PKCS-_002311-token"><span>Connecting using a PKCS #11 token<a class="copiable-link" href="#Connecting-using-a-PKCS-_002311-token"> &para;</a></span></h4>
<p>To connect to a server using a certificate and a private key present in a PKCS #11 token you 
need to substitute the PKCS 11 URLs in the x509certfile and x509keyfile parameters.
</p>
<p>Those can be found using &quot;p11tool &ndash;list-tokens&quot; and then listing all the objects in the
needed token, and using the appropriate.
</p><div class="example">
<pre class="example-preformatted">$ p11tool --list-tokens

Token 0:
	URL: pkcs11:model=PKCS15;manufacturer=MyMan;serial=1234;token=Test
	Label: Test
	Manufacturer: EnterSafe
	Model: PKCS15
	Serial: 1234

$ p11tool --login --list-certs &quot;pkcs11:model=PKCS15;manufacturer=MyMan;serial=1234;token=Test&quot;

Object 0:
	URL: pkcs11:model=PKCS15;manufacturer=MyMan;serial=1234;token=Test;object=client;type=cert
	Type: X.509 Certificate
	Label: client
	ID: 2a:97:0d:58:d1:51:3c:23:07:ae:4e:0d:72:26:03:7d:99:06:02:6a

$ MYCERT=&quot;pkcs11:model=PKCS15;manufacturer=MyMan;serial=1234;token=Test;object=client;type=cert&quot;
$ MYKEY=&quot;pkcs11:model=PKCS15;manufacturer=MyMan;serial=1234;token=Test;object=client;type=private&quot;
$ export MYCERT MYKEY

$ gnutls-cli www.example.com --x509keyfile $MYKEY --x509certfile $MYCERT
</pre></div>
<p>Notice that the private key only differs from the certificate in the type.
</p><hr>
<a class="node" id="gnutls_002dserv-Invocation"></a><div class="nav-panel">
<p>
[<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="heading" id="Invoking-gnutls_002dserv"><span>Invoking gnutls-serv<a class="copiable-link" href="#Invoking-gnutls_002dserv"> &para;</a></span></h3>
<a class="index-entry-id" id="index-gnutls_002dserv"></a>

<p>Server program that listens to incoming TLS connections.
</p>
<a class="anchor" id="gnutls_002dserv-usage"></a><h4 class="subheading" id="gnutls_002dserv-help_002fusage-_0028_002d_003f_0029"><span>gnutls-serv help/usage (<samp class="option">-?</samp>)<a class="copiable-link" href="#gnutls_002dserv-help_002fusage-_0028_002d_003f_0029"> &para;</a></span></h4>
<a class="index-entry-id" id="index-gnutls_002dserv-help"></a>

<p>The text printed is the same whether selected with the <code class="code">help</code> option
(<samp class="option">--help</samp>) or the <code class="code">more-help</code> option (<samp class="option">--more-help</samp>).  <code class="code">more-help</code> will print
the usage text by passing it through a pager program.
<code class="code">more-help</code> is disabled on platforms without a working
<code class="code">fork(2)</code> function.  The <code class="code">PAGER</code> environment variable is
used to select the program, defaulting to <samp class="file">more</samp>.  Both will exit
with a status code of 0.
</p>
<div class="example">
<pre class="example-preformatted">gnutls-serv - GnuTLS server
Usage:  gnutls-serv [ -&lt;flag&gt; [&lt;val&gt;] | --&lt;name&gt;[{=| }&lt;val&gt;] ]... 

None:

   -d, --debug=num            Enable debugging
				- it must be in the range:
				  0 to 9999
       --sni-hostname=str     Server's hostname for server name extension
       --sni-hostname-fatal   Send fatal alert on sni-hostname mismatch
       --alpn=str             Specify ALPN protocol to be enabled by the server
       --alpn-fatal           Send fatal alert on non-matching ALPN name
       --noticket             Don't accept session tickets
       --earlydata            Accept early data
       --maxearlydata=num     The maximum early data size to accept
				- it must be in the range:
				  1 to 2147483648
       --nocookie             Don't require cookie on DTLS sessions
   -g, --generate             Generate Diffie-Hellman parameters
   -q, --quiet                Suppress some messages
       --nodb                 Do not use a resumption database
       --http                 Act as an HTTP server
       --echo                 Act as an Echo server
       --crlf                 Do not replace CRLF by LF in Echo server mode
   -u, --udp                  Use DTLS (datagram TLS) over UDP
       --mtu=num              Set MTU for datagram TLS
				- it must be in the range:
				  0 to 17000
       --srtp-profiles=str    Offer SRTP profiles
   -a, --disable-client-cert  Do not request a client certificate
				- prohibits the option 'require-client-cert'
   -r, --require-client-cert  Require a client certificate
       --verify-client-cert   If a client certificate is sent then verify it
       --compress-cert=str    Compress certificate
   -b, --heartbeat            Activate heartbeat support
       --x509fmtder           Use DER format for certificates to read from
       --priority=str         Priorities string
       --dhparams=file        DH params file to use
				- file must pre-exist
       --x509cafile=str       Certificate file or PKCS #11 URL to use
       --x509crlfile=file     CRL file to use
				- file must pre-exist
       --x509keyfile=str      X.509 key file or PKCS #11 URL to use
       --x509certfile=str     X.509 Certificate file or PKCS #11 URL to use
       --rawpkkeyfile=str     Private key file (PKCS #8 or PKCS #12) or PKCS #11 URL to use
       --rawpkfile=str        Raw public-key file to use
				- requires the option 'rawpkkeyfile'
       --srppasswd=file       SRP password file to use
				- file must pre-exist
       --srppasswdconf=file   SRP password configuration file to use
				- file must pre-exist
       --pskpasswd=file       PSK password file to use
				- file must pre-exist
       --pskhint=str          PSK identity hint to use
       --ocsp-response=str    The OCSP response to send to client
       --ignore-ocsp-response-errors  Ignore any errors when setting the OCSP response
   -p, --port=num             The port to connect to
   -l, --list                 Print a list of the supported algorithms and modes
       --provider=file        Specify the PKCS #11 provider library
				- file must pre-exist
       --keymatexport=str     Label used for exporting keying material
       --keymatexportsize=num Size of the exported keying material
       --recordsize=num       The maximum record size to advertise
				- it must be in the range:
				  0 to 16384
       --httpdata=file        The data used as HTTP response
				- file must pre-exist
       --timeout=num          The timeout period for server
       --attime=str           Perform validation at the timestamp instead of the system time

Version, usage and configuration options:

   -v, --version[=arg]        output version information and exit
   -h, --help                 display extended usage information and exit
   -!, --more-help            extended usage information passed thru pager

Options are specified by doubled hyphens and their name or by a single
hyphen and the flag character.

Server program that listens to incoming TLS connections.

Please send bug reports to:  &lt;bugs@gnutls.org&gt;

</pre></div>

<h4 class="subheading" id="debug-option-_0028_002dd_0029_002e-1"><span>debug option (-d).<a class="copiable-link" href="#debug-option-_0028_002dd_0029_002e-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dserv-debug"></a>
<p>This is the &ldquo;enable debugging&rdquo; option.
This option takes a ArgumentType.NUMBER argument.
Specifies the debug level.
</p><h4 class="subheading" id="sni_002dhostname-option_002e-1"><span>sni-hostname option.<a class="copiable-link" href="#sni_002dhostname-option_002e-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dserv-sni_002dhostname"></a>
<p>This is the &ldquo;server&rsquo;s hostname for server name extension&rdquo; option.
This option takes a ArgumentType.STRING argument.
Server name of type host_name that the server will recognise as its own. If the server receives client hello with different name, it will send a warning-level unrecognized_name alert.
</p><h4 class="subheading" id="alpn-option_002e-1"><span>alpn option.<a class="copiable-link" href="#alpn-option_002e-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dserv-alpn"></a>
<p>This is the &ldquo;specify alpn protocol to be enabled by the server&rdquo; option.
This option takes a ArgumentType.STRING argument.
Specify the (textual) ALPN protocol for the server to use.
</p><h4 class="subheading" id="require_002dclient_002dcert-option-_0028_002dr_0029_002e"><span>require-client-cert option (-r).<a class="copiable-link" href="#require_002dclient_002dcert-option-_0028_002dr_0029_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dserv-require_002dclient_002dcert"></a>
<p>This is the &ldquo;require a client certificate&rdquo; option.
This option before 3.6.0 used to imply &ndash;verify-client-cert.
Since 3.6.0 it will no longer verify the certificate by default.
</p><h4 class="subheading" id="verify_002dclient_002dcert-option_002e"><span>verify-client-cert option.<a class="copiable-link" href="#verify_002dclient_002dcert-option_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dserv-verify_002dclient_002dcert"></a>
<p>This is the &ldquo;if a client certificate is sent then verify it&rdquo; option.
Do not require, but if a client certificate is sent then verify it and close the connection if invalid.
</p><h4 class="subheading" id="compress_002dcert-option_002e-1"><span>compress-cert option.<a class="copiable-link" href="#compress_002dcert-option_002e-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dserv-compress_002dcert"></a>
<p>This is the &ldquo;compress certificate&rdquo; option.
This option takes a ArgumentType.STRING argument.
This option sets a supported compression method for certificate compression.
</p><h4 class="subheading" id="heartbeat-option-_0028_002db_0029_002e"><span>heartbeat option (-b).<a class="copiable-link" href="#heartbeat-option-_0028_002db_0029_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dserv-heartbeat"></a>
<p>This is the &ldquo;activate heartbeat support&rdquo; option.
Regularly ping client via heartbeat extension messages
</p><h4 class="subheading" id="priority-option_002e-1"><span>priority option.<a class="copiable-link" href="#priority-option_002e-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dserv-priority"></a>
<p>This is the &ldquo;priorities string&rdquo; option.
This option takes a ArgumentType.STRING argument.
TLS algorithms and protocols to enable. You can
use predefined sets of ciphersuites such as PERFORMANCE,
NORMAL, SECURE128, SECURE256. The default is NORMAL.
</p>
<p>Check  the  GnuTLS  manual  on  section  &ldquo;Priority strings&rdquo; for more
information on allowed keywords
</p><h4 class="subheading" id="x509keyfile-option_002e"><span>x509keyfile option.<a class="copiable-link" href="#x509keyfile-option_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dserv-x509keyfile"></a>
<p>This is the &ldquo;x.509 key file or pkcs #11 url to use&rdquo; option.
This option takes a ArgumentType.STRING argument.
Specify the private key file or URI to use; it must correspond to
the certificate specified in &ndash;x509certfile. Multiple keys and certificates
can be specified with this option and in that case each occurrence of keyfile
must be followed by the corresponding x509certfile or vice-versa.
</p><h4 class="subheading" id="x509certfile-option_002e"><span>x509certfile option.<a class="copiable-link" href="#x509certfile-option_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dserv-x509certfile"></a>
<p>This is the &ldquo;x.509 certificate file or pkcs #11 url to use&rdquo; option.
This option takes a ArgumentType.STRING argument.
Specify the certificate file or URI to use; it must correspond to
the key specified in &ndash;x509keyfile. Multiple keys and certificates
can be specified with this option and in that case each occurrence of keyfile
must be followed by the corresponding x509certfile or vice-versa.
</p><h4 class="subheading" id="x509dsakeyfile-option_002e"><span>x509dsakeyfile option.<a class="copiable-link" href="#x509dsakeyfile-option_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dserv-x509dsakeyfile"></a>
<p>This is an alias for the <code class="code">x509keyfile</code> option,
see <a class="pxref" href="#gnutls_002dserv-x509keyfile">the x509keyfile option documentation</a>.
</p>
<h4 class="subheading" id="x509dsacertfile-option_002e"><span>x509dsacertfile option.<a class="copiable-link" href="#x509dsacertfile-option_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dserv-x509dsacertfile"></a>
<p>This is an alias for the <code class="code">x509certfile</code> option,
see <a class="pxref" href="#gnutls_002dserv-x509certfile">the x509certfile option documentation</a>.
</p>
<h4 class="subheading" id="x509ecckeyfile-option_002e"><span>x509ecckeyfile option.<a class="copiable-link" href="#x509ecckeyfile-option_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dserv-x509ecckeyfile"></a>
<p>This is an alias for the <code class="code">x509keyfile</code> option,
see <a class="pxref" href="#gnutls_002dserv-x509keyfile">the x509keyfile option documentation</a>.
</p>
<h4 class="subheading" id="x509ecccertfile-option_002e"><span>x509ecccertfile option.<a class="copiable-link" href="#x509ecccertfile-option_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dserv-x509ecccertfile"></a>
<p>This is an alias for the <code class="code">x509certfile</code> option,
see <a class="pxref" href="#gnutls_002dserv-x509certfile">the x509certfile option documentation</a>.
</p>
<h4 class="subheading" id="rawpkkeyfile-option_002e-1"><span>rawpkkeyfile option.<a class="copiable-link" href="#rawpkkeyfile-option_002e-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dserv-rawpkkeyfile"></a>
<p>This is the &ldquo;private key file (pkcs #8 or pkcs #12) or pkcs #11 url to use&rdquo; option.
This option takes a ArgumentType.STRING argument.
Specify the private key file or URI to use; it must correspond to
the raw public-key specified in &ndash;rawpkfile. Multiple key pairs
can be specified with this option and in that case each occurrence of keyfile
must be followed by the corresponding rawpkfile or vice-versa.
</p>
<p>In order to instruct the application to negotiate raw public keys one
must enable the respective certificate types via the priority strings (i.e. CTYPE-CLI-*
and CTYPE-SRV-* flags).
</p>
<p>Check  the  GnuTLS  manual  on  section  &ldquo;Priority strings&rdquo; for more
information on how to set certificate types.
</p><h4 class="subheading" id="rawpkfile-option_002e-1"><span>rawpkfile option.<a class="copiable-link" href="#rawpkfile-option_002e-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dserv-rawpkfile"></a>
<p>This is the &ldquo;raw public-key file to use&rdquo; option.
This option takes a ArgumentType.STRING argument.
</p>
<p>This option has some usage constraints.  It:
</p><ul class="itemize mark-bullet">
<li>must appear in combination with the following options:
rawpkkeyfile.
</li></ul>

<p>Specify the raw public-key file to use; it must correspond to
the private key specified in &ndash;rawpkkeyfile. Multiple key pairs
can be specified with this option and in that case each occurrence of keyfile
must be followed by the corresponding rawpkfile or vice-versa.
</p>
<p>In order to instruct the application to negotiate raw public keys one
must enable the respective certificate types via the priority strings (i.e. CTYPE-CLI-*
and CTYPE-SRV-* flags).
</p>
<p>Check  the  GnuTLS  manual  on  section  &ldquo;Priority strings&rdquo; for more
information on how to set certificate types.
</p><h4 class="subheading" id="ocsp_002dresponse-option_002e"><span>ocsp-response option.<a class="copiable-link" href="#ocsp_002dresponse-option_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dserv-ocsp_002dresponse"></a>
<p>This is the &ldquo;the ocsp response to send to client&rdquo; option.
This option takes a ArgumentType.STRING argument.
If the client requested an OCSP response, return data from this file to the client.
</p><h4 class="subheading" id="ignore_002docsp_002dresponse_002derrors-option_002e"><span>ignore-ocsp-response-errors option.<a class="copiable-link" href="#ignore_002docsp_002dresponse_002derrors-option_002e"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dserv-ignore_002docsp_002dresponse_002derrors"></a>
<p>This is the &ldquo;ignore any errors when setting the ocsp response&rdquo; option.
That option instructs gnutls to not attempt to match the provided OCSP responses with the certificates.
</p><h4 class="subheading" id="list-option-_0028_002dl_0029_002e-1"><span>list option (-l).<a class="copiable-link" href="#list-option-_0028_002dl_0029_002e-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dserv-list"></a>
<p>This is the &ldquo;print a list of the supported algorithms and modes&rdquo; option.
Print a list of the supported algorithms and modes. If a priority string is given then only the enabled ciphersuites are shown.
</p><h4 class="subheading" id="provider-option_002e-1"><span>provider option.<a class="copiable-link" href="#provider-option_002e-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dserv-provider"></a>
<p>This is the &ldquo;specify the pkcs #11 provider library&rdquo; option.
This option takes a ArgumentType.FILE argument.
This will override the default options in /etc/gnutls/pkcs11.conf
</p><h4 class="subheading" id="attime-option_002e-1"><span>attime option.<a class="copiable-link" href="#attime-option_002e-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dserv-attime"></a>
<p>This is the &ldquo;perform validation at the timestamp instead of the system time&rdquo; option.
This option takes a ArgumentType.STRING argument <samp class="file">timestamp</samp>.
timestamp is an instance in time encoded as Unix time or in a human
 readable timestring such as &quot;29 Feb 2004&quot;, &quot;2004-02-29&quot;.
Full documentation available at 
&lt;https://www.gnu.org/software/coreutils/manual/html_node/Date-input-formats.html&gt;
or locally via info &rsquo;(coreutils) date invocation&rsquo;.
</p><h4 class="subheading" id="version-option-_0028_002dv_0029_002e-1"><span>version option (-v).<a class="copiable-link" href="#version-option-_0028_002dv_0029_002e-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dserv-version"></a>
<p>This is the &ldquo;output version information and exit&rdquo; option.
This option takes a ArgumentType.KEYWORD argument.
Output version of program and exit.  The default mode is &lsquo;v&rsquo;, a simple
version.  The &lsquo;c&rsquo; mode will print copyright information and &lsquo;n&rsquo; will
print the full copyright notice.
</p><h4 class="subheading" id="help-option-_0028_002dh_0029_002e-1"><span>help option (-h).<a class="copiable-link" href="#help-option-_0028_002dh_0029_002e-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dserv-help"></a>
<p>This is the &ldquo;display extended usage information and exit&rdquo; option.
Display usage information and exit.
</p><h4 class="subheading" id="more_002dhelp-option-_0028_002d_0021_0029_002e-1"><span>more-help option (-!).<a class="copiable-link" href="#more_002dhelp-option-_0028_002d_0021_0029_002e-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dserv-more_002dhelp"></a>
<p>This is the &ldquo;extended usage information passed thru pager&rdquo; option.
Pass the extended usage information through a pager.
<a class="anchor" id="gnutls_002dserv-exit-status"></a></p><h4 class="subheading" id="gnutls_002dserv-exit-status-1"><span>gnutls-serv exit status<a class="copiable-link" href="#gnutls_002dserv-exit-status-1"> &para;</a></span></h4>

<p>One of the following exit values will be returned:
</p><dl class="table">
<dt>&lsquo;<samp class="samp">0 (EXIT_SUCCESS)</samp>&rsquo;</dt>
<dd><p>Successful program execution.
</p></dd>
<dt>&lsquo;<samp class="samp">1 (EXIT_FAILURE)</samp>&rsquo;</dt>
<dd><p>The operation failed or the command syntax was not valid.
</p></dd>
</dl>
<a class="anchor" id="gnutls_002dserv-See-Also"></a><h4 class="subsubheading" id="gnutls_002dserv-See-Also-1"><span>gnutls-serv See Also<a class="copiable-link" href="#gnutls_002dserv-See-Also-1"> &para;</a></span></h4>
<p>gnutls-cli-debug(1), gnutls-cli(1)
<a class="anchor" id="gnutls_002dserv-Examples"></a></p><h4 class="subsubheading" id="gnutls_002dserv-Examples-1"><span>gnutls-serv Examples<a class="copiable-link" href="#gnutls_002dserv-Examples-1"> &para;</a></span></h4>
<p>Running your own TLS server based on GnuTLS can be useful when
debugging clients and/or GnuTLS itself.  This section describes how to
use <code class="code">gnutls-serv</code> as a simple HTTPS server.
</p>
<p>The most basic server can be started as:
</p>
<div class="example">
<pre class="example-preformatted">gnutls-serv --http --priority &quot;NORMAL:+ANON-ECDH:+ANON-DH&quot;
</pre></div>

<p>It will only support anonymous ciphersuites, which many TLS clients
refuse to use.
</p>
<p>The next step is to add support for X.509.  First we generate a CA:
</p>
<div class="example">
<pre class="example-preformatted">$ certtool --generate-privkey &gt; x509-ca-key.pem
$ echo 'cn = GnuTLS test CA' &gt; ca.tmpl
$ echo 'ca' &gt;&gt; ca.tmpl
$ echo 'cert_signing_key' &gt;&gt; ca.tmpl
$ certtool --generate-self-signed --load-privkey x509-ca-key.pem \
  --template ca.tmpl --outfile x509-ca.pem
</pre></div>

<p>Then generate a server certificate.  Remember to change the dns_name
value to the name of your server host, or skip that command to avoid
the field.
</p>
<div class="example">
<pre class="example-preformatted">$ certtool --generate-privkey &gt; x509-server-key.pem
$ echo 'organization = GnuTLS test server' &gt; server.tmpl
$ echo 'cn = test.gnutls.org' &gt;&gt; server.tmpl
$ echo 'tls_www_server' &gt;&gt; server.tmpl
$ echo 'encryption_key' &gt;&gt; server.tmpl
$ echo 'signing_key' &gt;&gt; server.tmpl
$ echo 'dns_name = test.gnutls.org' &gt;&gt; server.tmpl
$ certtool --generate-certificate --load-privkey x509-server-key.pem \
  --load-ca-certificate x509-ca.pem --load-ca-privkey x509-ca-key.pem \
  --template server.tmpl --outfile x509-server.pem
</pre></div>

<p>For use in the client, you may want to generate a client certificate
as well.
</p>
<div class="example">
<pre class="example-preformatted">$ certtool --generate-privkey &gt; x509-client-key.pem
$ echo 'cn = GnuTLS test client' &gt; client.tmpl
$ echo 'tls_www_client' &gt;&gt; client.tmpl
$ echo 'encryption_key' &gt;&gt; client.tmpl
$ echo 'signing_key' &gt;&gt; client.tmpl
$ certtool --generate-certificate --load-privkey x509-client-key.pem \
  --load-ca-certificate x509-ca.pem --load-ca-privkey x509-ca-key.pem \
  --template client.tmpl --outfile x509-client.pem
</pre></div>

<p>To be able to import the client key/certificate into some
applications, you will need to convert them into a PKCS#12 structure.
This also encrypts the security sensitive key with a password.
</p>
<div class="example">
<pre class="example-preformatted">$ certtool --to-p12 --load-ca-certificate x509-ca.pem \
  --load-privkey x509-client-key.pem --load-certificate x509-client.pem \
  --outder --outfile x509-client.p12
</pre></div>

<p>For icing, we&rsquo;ll create a proxy certificate for the client too.
</p>
<div class="example">
<pre class="example-preformatted">$ certtool --generate-privkey &gt; x509-proxy-key.pem
$ echo 'cn = GnuTLS test client proxy' &gt; proxy.tmpl
$ certtool --generate-proxy --load-privkey x509-proxy-key.pem \
  --load-ca-certificate x509-client.pem --load-ca-privkey x509-client-key.pem \
  --load-certificate x509-client.pem --template proxy.tmpl \
  --outfile x509-proxy.pem
</pre></div>

<p>Then start the server again:
</p>
<div class="example">
<pre class="example-preformatted">$ gnutls-serv --http \
            --x509cafile x509-ca.pem \
            --x509keyfile x509-server-key.pem \
            --x509certfile x509-server.pem
</pre></div>

<p>Try connecting to the server using your web browser.  Note that the
server listens to port 5556 by default.
</p>
<p>While you are at it, to allow connections using ECDSA, you can also
create a ECDSA key and certificate for the server.  These credentials
will be used in the final example below.
</p>
<div class="example">
<pre class="example-preformatted">$ certtool --generate-privkey --ecdsa &gt; x509-server-key-ecc.pem
$ certtool --generate-certificate --load-privkey x509-server-key-ecc.pem \
  --load-ca-certificate x509-ca.pem --load-ca-privkey x509-ca-key.pem \
  --template server.tmpl --outfile x509-server-ecc.pem
</pre></div>


<p>The next step is to add support for SRP authentication. This requires
an SRP password file created with <code class="code">srptool</code>.
To start the server with SRP support:
</p>
<div class="example">
<pre class="example-preformatted">gnutls-serv --http --priority NORMAL:+SRP-RSA:+SRP \
            --srppasswdconf srp-tpasswd.conf \
            --srppasswd srp-passwd.txt
</pre></div>

<p>Let&rsquo;s also start a server with support for PSK. This would require
a password file created with <code class="code">psktool</code>.
</p>
<div class="example">
<pre class="example-preformatted">gnutls-serv --http --priority NORMAL:+ECDHE-PSK:+PSK \
            --pskpasswd psk-passwd.txt
</pre></div>

<p>If you want a server with support for raw public-keys we can also add these
credentials. Note however that there is no identity information linked to these
keys as is the case with regular x509 certificates. Authentication must be done
via different means. Also we need to explicitly enable raw public-key certificates
via the priority strings.
</p>
<div class="example">
<pre class="example-preformatted">gnutls-serv --http --priority NORMAL:+CTYPE-CLI-RAWPK:+CTYPE-SRV-RAWPK \
            --rawpkfile srv.rawpk.pem \
            --rawpkkeyfile srv.key.pem
</pre></div>


<p>Finally, we start the server with all the earlier parameters and you
get this command:
</p>
<div class="example">
<pre class="example-preformatted">gnutls-serv --http --priority NORMAL:+PSK:+SRP:+CTYPE-CLI-RAWPK:+CTYPE-SRV-RAWPK \
            --x509cafile x509-ca.pem \
            --x509keyfile x509-server-key.pem \
            --x509certfile x509-server.pem \
            --x509keyfile x509-server-key-ecc.pem \
            --x509certfile x509-server-ecc.pem \
            --srppasswdconf srp-tpasswd.conf \
            --srppasswd srp-passwd.txt \
            --pskpasswd psk-passwd.txt \
            --rawpkfile srv.rawpk.pem \
            --rawpkkeyfile srv.key.pem
</pre></div>
<hr>
<a class="node" id="gnutls_002dcli_002ddebug-Invocation"></a><div class="nav-panel">
<p>
[<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="heading" id="Invoking-gnutls_002dcli_002ddebug"><span>Invoking gnutls-cli-debug<a class="copiable-link" href="#Invoking-gnutls_002dcli_002ddebug"> &para;</a></span></h3>
<a class="index-entry-id" id="index-gnutls_002dcli_002ddebug"></a>

<p>TLS debug client. It sets up multiple TLS connections to 
a server and queries its capabilities. It was created to assist in debugging 
GnuTLS, but it might be useful to extract a TLS server&rsquo;s capabilities.
It connects to a TLS server, performs tests and print the server&rsquo;s 
capabilities. If called with the &lsquo;-V&rsquo; parameter more checks will be performed.
Can be used to check for servers with special needs or bugs.
</p>
<a class="anchor" id="gnutls_002dcli_002ddebug-usage"></a><h4 class="subheading" id="gnutls_002dcli_002ddebug-help_002fusage-_0028_002d_003f_0029"><span>gnutls-cli-debug help/usage (<samp class="option">-?</samp>)<a class="copiable-link" href="#gnutls_002dcli_002ddebug-help_002fusage-_0028_002d_003f_0029"> &para;</a></span></h4>
<a class="index-entry-id" id="index-gnutls_002dcli_002ddebug-help"></a>

<p>The text printed is the same whether selected with the <code class="code">help</code> option
(<samp class="option">--help</samp>) or the <code class="code">more-help</code> option (<samp class="option">--more-help</samp>).  <code class="code">more-help</code> will print
the usage text by passing it through a pager program.
<code class="code">more-help</code> is disabled on platforms without a working
<code class="code">fork(2)</code> function.  The <code class="code">PAGER</code> environment variable is
used to select the program, defaulting to <samp class="file">more</samp>.  Both will exit
with a status code of 0.
</p>
<div class="example">
<pre class="example-preformatted">gnutls-cli-debug - GnuTLS debug client
Usage:  gnutls-cli-debug [ -&lt;flag&gt; [&lt;val&gt;] | --&lt;name&gt;[{=| }&lt;val&gt;] ]... [hostname]

None:

   -d, --debug=num            Enable debugging
				- it must be in the range:
				  0 to 9999
   -V, --verbose              More verbose output
   -p, --port=num             The port to connect to
				- it must be in the range:
				  0 to 65536
       --app-proto            an alias for the 'starttls-proto' option
       --starttls-proto=str   The application protocol to be used to obtain the server's certificate (https, ftp, smtp, imap, ldap, xmpp, lmtp, pop3, nntp, sieve, postgres)
       --attime=str           Perform validation at the timestamp instead of the system time

Version, usage and configuration options:

   -v, --version[=arg]        output version information and exit
   -h, --help                 display extended usage information and exit
   -!, --more-help            extended usage information passed thru pager

Options are specified by doubled hyphens and their name or by a single
hyphen and the flag character.
Operands and options may be intermixed.  They will be reordered.

TLS debug client. It sets up multiple TLS connections to 
a server and queries its capabilities. It was created to assist in debugging 
GnuTLS, but it might be useful to extract a TLS server's capabilities.
It connects to a TLS server, performs tests and print the server's 
capabilities. If called with the `-V' parameter more checks will be performed.
Can be used to check for servers with special needs or bugs.

Please send bug reports to:  &lt;bugs@gnutls.org&gt;

</pre></div>

<h4 class="subheading" id="debug-option-_0028_002dd_0029_002e-2"><span>debug option (-d).<a class="copiable-link" href="#debug-option-_0028_002dd_0029_002e-2"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli_002ddebug-debug"></a>
<p>This is the &ldquo;enable debugging&rdquo; option.
This option takes a ArgumentType.NUMBER argument.
Specifies the debug level.
</p><h4 class="subheading" id="app_002dproto-option_002e-1"><span>app-proto option.<a class="copiable-link" href="#app_002dproto-option_002e-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli_002ddebug-app_002dproto"></a>
<p>This is an alias for the <code class="code">starttls-proto</code> option,
see <a class="pxref" href="#gnutls_002dcli_002ddebug-starttls_002dproto">the starttls-proto option documentation</a>.
</p>
<h4 class="subheading" id="starttls_002dproto-option_002e-1"><span>starttls-proto option.<a class="copiable-link" href="#starttls_002dproto-option_002e-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli_002ddebug-starttls_002dproto"></a>
<p>This is the &ldquo;the application protocol to be used to obtain the server&rsquo;s certificate (https, ftp, smtp, imap, ldap, xmpp, lmtp, pop3, nntp, sieve, postgres)&rdquo; option.
This option takes a ArgumentType.STRING argument.
Specify the application layer protocol for STARTTLS. If the protocol is supported, gnutls-cli will proceed to the TLS negotiation.
</p><h4 class="subheading" id="attime-option_002e-2"><span>attime option.<a class="copiable-link" href="#attime-option_002e-2"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli_002ddebug-attime"></a>
<p>This is the &ldquo;perform validation at the timestamp instead of the system time&rdquo; option.
This option takes a ArgumentType.STRING argument <samp class="file">timestamp</samp>.
timestamp is an instance in time encoded as Unix time or in a human
 readable timestring such as &quot;29 Feb 2004&quot;, &quot;2004-02-29&quot;.
Full documentation available at 
&lt;https://www.gnu.org/software/coreutils/manual/html_node/Date-input-formats.html&gt;
or locally via info &rsquo;(coreutils) date invocation&rsquo;.
</p><h4 class="subheading" id="version-option-_0028_002dv_0029_002e-2"><span>version option (-v).<a class="copiable-link" href="#version-option-_0028_002dv_0029_002e-2"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli_002ddebug-version"></a>
<p>This is the &ldquo;output version information and exit&rdquo; option.
This option takes a ArgumentType.KEYWORD argument.
Output version of program and exit.  The default mode is &lsquo;v&rsquo;, a simple
version.  The &lsquo;c&rsquo; mode will print copyright information and &lsquo;n&rsquo; will
print the full copyright notice.
</p><h4 class="subheading" id="help-option-_0028_002dh_0029_002e-2"><span>help option (-h).<a class="copiable-link" href="#help-option-_0028_002dh_0029_002e-2"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli_002ddebug-help"></a>
<p>This is the &ldquo;display extended usage information and exit&rdquo; option.
Display usage information and exit.
</p><h4 class="subheading" id="more_002dhelp-option-_0028_002d_0021_0029_002e-2"><span>more-help option (-!).<a class="copiable-link" href="#more_002dhelp-option-_0028_002d_0021_0029_002e-2"> &para;</a></span></h4>
<a class="anchor" id="gnutls_002dcli_002ddebug-more_002dhelp"></a>
<p>This is the &ldquo;extended usage information passed thru pager&rdquo; option.
Pass the extended usage information through a pager.
<a class="anchor" id="gnutls_002dcli_002ddebug-exit-status"></a></p><h4 class="subheading" id="gnutls_002dcli_002ddebug-exit-status-1"><span>gnutls-cli-debug exit status<a class="copiable-link" href="#gnutls_002dcli_002ddebug-exit-status-1"> &para;</a></span></h4>

<p>One of the following exit values will be returned:
</p><dl class="table">
<dt>&lsquo;<samp class="samp">0 (EXIT_SUCCESS)</samp>&rsquo;</dt>
<dd><p>Successful program execution.
</p></dd>
<dt>&lsquo;<samp class="samp">1 (EXIT_FAILURE)</samp>&rsquo;</dt>
<dd><p>The operation failed or the command syntax was not valid.
</p></dd>
</dl>
<a class="anchor" id="gnutls_002dcli_002ddebug-See-Also"></a><h4 class="subsubheading" id="gnutls_002dcli_002ddebug-See-Also-1"><span>gnutls-cli-debug See Also<a class="copiable-link" href="#gnutls_002dcli_002ddebug-See-Also-1"> &para;</a></span></h4>
<p>gnutls-cli(1), gnutls-serv(1)
<a class="anchor" id="gnutls_002dcli_002ddebug-Examples"></a></p><h4 class="subsubheading" id="gnutls_002dcli_002ddebug-Examples-1"><span>gnutls-cli-debug Examples<a class="copiable-link" href="#gnutls_002dcli_002ddebug-Examples-1"> &para;</a></span></h4>
<div class="example">
<pre class="example-preformatted">$ gnutls-cli-debug localhost
GnuTLS debug client 3.5.0
Checking localhost:443
                             for SSL 3.0 (RFC6101) support... yes
                        whether we need to disable TLS 1.2... no
                        whether we need to disable TLS 1.1... no
                        whether we need to disable TLS 1.0... no
                        whether %NO_EXTENSIONS is required... no
                               whether %COMPAT is required... no
                             for TLS 1.0 (RFC2246) support... yes
                             for TLS 1.1 (RFC4346) support... yes
                             for TLS 1.2 (RFC5246) support... yes
                                  fallback from TLS 1.6 to... TLS1.2
                        for RFC7507 inappropriate fallback... yes
                                     for HTTPS server name... Local
                               for certificate chain order... sorted
                  for safe renegotiation (RFC5746) support... yes
                     for Safe renegotiation support (SCSV)... no
                    for encrypt-then-MAC (RFC7366) support... no
                   for ext master secret (RFC7627) support... no
                           for heartbeat (RFC6520) support... no
                       for version rollback bug in RSA PMS... dunno
                  for version rollback bug in Client Hello... no
            whether the server ignores the RSA PMS version... yes
whether small records (512 bytes) are tolerated on handshake... yes
    whether cipher suites not in SSL 3.0 spec are accepted... yes
whether a bogus TLS record version in the client hello is accepted... yes
         whether the server understands TLS closure alerts... partially
            whether the server supports session resumption... yes
                      for anonymous authentication support... no
                      for ephemeral Diffie-Hellman support... no
                   for ephemeral EC Diffie-Hellman support... yes
                    ephemeral EC Diffie-Hellman group info... SECP256R1
                  for AES-128-GCM cipher (RFC5288) support... yes
                  for AES-128-CCM cipher (RFC6655) support... no
                for AES-128-CCM-8 cipher (RFC6655) support... no
                  for AES-128-CBC cipher (RFC3268) support... yes
             for CAMELLIA-128-GCM cipher (RFC6367) support... no
             for CAMELLIA-128-CBC cipher (RFC5932) support... no
                     for 3DES-CBC cipher (RFC2246) support... yes
                  for ARCFOUR 128 cipher (RFC2246) support... yes
                                       for MD5 MAC support... yes
                                      for SHA1 MAC support... yes
                                    for SHA256 MAC support... yes
                              for ZLIB compression support... no
                     for max record size (RFC6066) support... no
                for OCSP status response (RFC6066) support... no
              for OpenPGP authentication (RFC6091) support... no
</pre></div>

<p>You could also use the client to debug services with starttls capability.
</p><div class="example">
<pre class="example-preformatted">$ gnutls-cli-debug --starttls-proto smtp --port 25 localhost
</pre></div>


<hr>
</div>
<div class="chapter-level-extent" id="Internal-architecture-of-GnuTLS">
<div class="nav-panel">
<p>
Next: <a href="#Upgrading-from-previous-versions" accesskey="n" rel="next">Upgrading from previous versions</a>, Previous: <a href="#Other-included-programs" accesskey="p" rel="prev">Other included programs</a>, Up: <a href="#Top" accesskey="u" rel="up">GnuTLS</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h2 class="chapter" id="Internal-Architecture-of-GnuTLS"><span>11 Internal Architecture of GnuTLS<a class="copiable-link" href="#Internal-Architecture-of-GnuTLS"> &para;</a></span></h2>
<a class="index-entry-id" id="index-internal-architecture"></a>

<p>This chapter is to give a brief description of the
way <abbr class="acronym">GnuTLS</abbr> works. The focus is to give an idea
to potential developers and those who want to know what
happens inside the black box.
</p>

<ul class="mini-toc">
<li><a href="#The-TLS-Protocol" accesskey="1">The TLS Protocol</a></li>
<li><a href="#TLS-Handshake-Protocol" accesskey="2">TLS Handshake Protocol</a></li>
<li><a href="#TLS-Authentication-Methods" accesskey="3">TLS Authentication Methods</a></li>
<li><a href="#TLS-Hello-Extension-Handling" accesskey="4">TLS Extension Handling</a></li>
<li><a href="#Cryptographic-Backend" accesskey="5">Cryptographic Backend</a></li>
<li><a href="#Random-Number-Generators_002dinternals" accesskey="6">Random Number Generators</a></li>
<li><a href="#FIPS140_002d2-mode" accesskey="7">FIPS140-2 mode</a></li>
</ul>
<hr>
<div class="section-level-extent" id="The-TLS-Protocol">
<div class="nav-panel">
<p>
Next: <a href="#TLS-Handshake-Protocol" accesskey="n" rel="next">TLS Handshake Protocol</a>, Up: <a href="#Internal-architecture-of-GnuTLS" accesskey="u" rel="up">Internal Architecture of GnuTLS</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="The-TLS-Protocol-1"><span>11.1 The TLS Protocol<a class="copiable-link" href="#The-TLS-Protocol-1"> &para;</a></span></h3>
<p>The main use case for the TLS protocol is shown in <a class="ref" href="#fig_002dclient_002dserver">Figure 11.1</a>.
A user of a library implementing the protocol expects no less than this functionality,
i.e., to be able to set parameters such as the accepted security level, perform a
negotiation with the peer and be able to exchange data.
</p>
<div class="float" id="fig_002dclient_002dserver">
<img class="image" src="gnutls-client-server-use-case.png" alt="gnutls-client-server-use-case">
<div class="caption"><p><strong class="strong">Figure 11.1: </strong>TLS protocol use case.</p></div></div>
<hr>
</div>
<div class="section-level-extent" id="TLS-Handshake-Protocol">
<div class="nav-panel">
<p>
Next: <a href="#TLS-Authentication-Methods" accesskey="n" rel="next">TLS Authentication Methods</a>, Previous: <a href="#The-TLS-Protocol" accesskey="p" rel="prev">The TLS Protocol</a>, Up: <a href="#Internal-architecture-of-GnuTLS" accesskey="u" rel="up">Internal Architecture of GnuTLS</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="TLS-Handshake-Protocol-1"><span>11.2 TLS Handshake Protocol<a class="copiable-link" href="#TLS-Handshake-Protocol-1"> &para;</a></span></h3>
<p>The <abbr class="acronym">GnuTLS</abbr> handshake protocol is implemented as a state
machine that waits for input or returns immediately when the non-blocking
transport layer functions are used. The main idea is shown in <a class="ref" href="#fig_002dgnutls_002dhandshake">Figure 11.2</a>.
</p>
<div class="float" id="fig_002dgnutls_002dhandshake">
<img class="image" src="gnutls-handshake-state.png" alt="gnutls-handshake-state">
<div class="caption"><p><strong class="strong">Figure 11.2: </strong>GnuTLS handshake state machine.</p></div></div>
<p>Also the way the input is processed varies per ciphersuite. Several
implementations of the internal handlers are available and
<a class="ref" href="#gnutls_005fhandshake">gnutls_handshake</a> only multiplexes the input to the appropriate
handler. For example a <abbr class="acronym">PSK</abbr> ciphersuite has a different
implementation of the <code class="code">process_client_key_exchange</code> than a
certificate ciphersuite. We illustrate the idea in <a class="ref" href="#fig_002dgnutls_002dhandshake_002dsequence">Figure 11.3</a>.
</p>
<div class="float" id="fig_002dgnutls_002dhandshake_002dsequence">
<img class="image" src="gnutls-handshake-sequence.png" alt="gnutls-handshake-sequence">
<div class="caption"><p><strong class="strong">Figure 11.3: </strong>GnuTLS handshake process sequence.</p></div></div>
<hr>
</div>
<div class="section-level-extent" id="TLS-Authentication-Methods">
<div class="nav-panel">
<p>
Next: <a href="#TLS-Hello-Extension-Handling" accesskey="n" rel="next">TLS Extension Handling</a>, Previous: <a href="#TLS-Handshake-Protocol" accesskey="p" rel="prev">TLS Handshake Protocol</a>, Up: <a href="#Internal-architecture-of-GnuTLS" accesskey="u" rel="up">Internal Architecture of GnuTLS</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="TLS-Authentication-Methods-1"><span>11.3 TLS Authentication Methods<a class="copiable-link" href="#TLS-Authentication-Methods-1"> &para;</a></span></h3>
<p>In <abbr class="acronym">GnuTLS</abbr> authentication methods can be implemented quite
easily.  Since the required changes to add a new authentication method
affect only the handshake protocol, a simple interface is used. An
authentication method needs to implement the functions shown below.
</p>
<pre class="verbatim">typedef struct
{
  const char *name;
  int (*gnutls_generate_server_certificate) (gnutls_session_t, gnutls_buffer_st*);
  int (*gnutls_generate_client_certificate) (gnutls_session_t, gnutls_buffer_st*);
  int (*gnutls_generate_server_kx) (gnutls_session_t, gnutls_buffer_st*);
  int (*gnutls_generate_client_kx) (gnutls_session_t, gnutls_buffer_st*);
  int (*gnutls_generate_client_cert_vrfy) (gnutls_session_t, gnutls_buffer_st *);
  int (*gnutls_generate_server_certificate_request) (gnutls_session_t,
                                                     gnutls_buffer_st *);

  int (*gnutls_process_server_certificate) (gnutls_session_t, opaque *,
                                            size_t);
  int (*gnutls_process_client_certificate) (gnutls_session_t, opaque *,
                                            size_t);
  int (*gnutls_process_server_kx) (gnutls_session_t, opaque *, size_t);
  int (*gnutls_process_client_kx) (gnutls_session_t, opaque *, size_t);
  int (*gnutls_process_client_cert_vrfy) (gnutls_session_t, opaque *, size_t);
  int (*gnutls_process_server_certificate_request) (gnutls_session_t,
                                                    opaque *, size_t);
} mod_auth_st;
</pre>
<p>Those functions are responsible for the
interpretation of the handshake protocol messages. It is common for such
functions to read data from one or more <code class="code">credentials_t</code>
structures<a class="footnote" id="DOCF23" href="#FOOT23"><sup>23</sup></a> and write data,
such as certificates, usernames etc. to <code class="code">auth_info_t</code> structures.
</p>

<p>Simple examples of existing authentication methods can be seen in
<code class="code">auth/psk.c</code> for PSK ciphersuites and <code class="code">auth/srp.c</code> for SRP
ciphersuites. After implementing these functions the structure holding
its pointers has to be registered in <code class="code">gnutls_algorithms.c</code> in the
<code class="code">_gnutls_kx_algorithms</code> structure.
</p>
<hr>
</div>
<div class="section-level-extent" id="TLS-Hello-Extension-Handling">
<div class="nav-panel">
<p>
Next: <a href="#Cryptographic-Backend" accesskey="n" rel="next">Cryptographic Backend</a>, Previous: <a href="#TLS-Authentication-Methods" accesskey="p" rel="prev">TLS Authentication Methods</a>, Up: <a href="#Internal-architecture-of-GnuTLS" accesskey="u" rel="up">Internal Architecture of GnuTLS</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="TLS-Extension-Handling"><span>11.4 TLS Extension Handling<a class="copiable-link" href="#TLS-Extension-Handling"> &para;</a></span></h3>
<p>As with authentication methods, adding TLS hello extensions can be done
quite easily by implementing the interface shown below.
</p>
<pre class="verbatim">typedef int (*gnutls_ext_recv_func) (gnutls_session_t session,
                                     const unsigned char *data, size_t len);
typedef int (*gnutls_ext_send_func) (gnutls_session_t session,
                                     gnutls_buffer_st *extdata);
</pre>
<p>Here there are two main functions, one for parsing the received extension data
and one for formatting the extension data that must be send. These functions
have to check internally whether they operate within a client or a server session.
</p>
<p>A simple example of an extension handler can be seen in
<code class="code">lib/ext/srp.c</code> in GnuTLS&rsquo; source code. After implementing these functions,
the extension has to be registered. Registering an extension can be done in two
ways. You can create a GnuTLS internal extension and register it in
<code class="code">hello_ext.c</code> or write an external extension (not inside GnuTLS but
inside an application using GnuTLS) and register it via the exported functions
<a class="ref" href="#gnutls_005fsession_005fext_005fregister">gnutls_session_ext_register</a> or <a class="ref" href="#gnutls_005fext_005fregister">gnutls_ext_register</a>.
</p>
<h4 class="subheading" id="Adding-a-new-TLS-hello-extension"><span>Adding a new TLS hello extension<a class="copiable-link" href="#Adding-a-new-TLS-hello-extension"> &para;</a></span></h4>

<p>Adding support for a new TLS hello extension is done from time to time, and
the process to do so is not difficult. Here are the steps you need to
follow if you wish to do this yourself. For the sake of discussion, let&rsquo;s
consider adding support for the hypothetical TLS extension <code class="code">foobar</code>.
The following section is about adding an hello extension to GnuTLS itself.
For custom application extensions you should check the exported functions
<a class="ref" href="#gnutls_005fsession_005fext_005fregister">gnutls_session_ext_register</a> or <a class="ref" href="#gnutls_005fext_005fregister">gnutls_ext_register</a>.
</p>
<h4 class="subsubheading" id="Add-configure-option-like-_002d_002denable_002dfoobar-or-_002d_002ddisable_002dfoobar_002e"><span>Add <code class="code">configure</code> option like <code class="code">--enable-foobar</code> or <code class="code">--disable-foobar</code>.<a class="copiable-link" href="#Add-configure-option-like-_002d_002denable_002dfoobar-or-_002d_002ddisable_002dfoobar_002e"> &para;</a></span></h4>

<p>This step is useful when the extension code is large and it might be desirable
under some circumstances to be able to leave out the extension during compilation of GnuTLS.
If you don&rsquo;t need this kind of feature this step can be safely skipped.
</p>
<p>Whether to choose enable or disable depends on whether you intend to make the extension be
enabled by default. Look at existing checks (i.e., SRP, authz) for
how to model the code. For example:
</p>
<div class="example">
<pre class="example-preformatted">AC_MSG_CHECKING([whether to disable foobar support])
AC_ARG_ENABLE(foobar,
	AS_HELP_STRING([--disable-foobar],
		[disable foobar support]),
	ac_enable_foobar=no)
if test x$ac_enable_foobar != xno; then
 AC_MSG_RESULT(no)
 AC_DEFINE(ENABLE_FOOBAR, 1, [enable foobar])
else
 ac_full=0
 AC_MSG_RESULT(yes)
fi
AM_CONDITIONAL(ENABLE_FOOBAR, test &quot;$ac_enable_foobar&quot; != &quot;no&quot;)
</pre></div>

<p>These lines should go in <code class="code">lib/m4/hooks.m4</code>.
</p>
<h4 class="subsubheading" id="Add-an-extension-identifier-to-extensions_005ft-in-gnutls_005fint_002eh_002e"><span>Add an extension identifier to <code class="code">extensions_t</code> in <code class="code">gnutls_int.h</code>.<a class="copiable-link" href="#Add-an-extension-identifier-to-extensions_005ft-in-gnutls_005fint_002eh_002e"> &para;</a></span></h4>

<p>A good name for the identifier would be GNUTLS_EXTENSION_FOOBAR. If the
extension that you are implementing is an extension that is officially
registered by IANA then it is recommended to use its official name such
that the extension can be correctly identified by other developers. Check
with <a class="url" href="https://www.iana.org/assignments/tls-extensiontype-values">https://www.iana.org/assignments/tls-extensiontype-values</a>
for registered extensions.
</p>
<h4 class="subsubheading" id="Register-the-extension-in-lib_002fhello_005fext_002ec_002e"><span>Register the extension in <code class="code">lib/hello_ext.c</code>.<a class="copiable-link" href="#Register-the-extension-in-lib_002fhello_005fext_002ec_002e"> &para;</a></span></h4>

<p>In order for the extension to be executed you need to register it in the
<code class="code">static hello_ext_entry_st const *extfunc[]</code> list in <code class="code">lib/hello_ext.c</code>.
</p>
<p>A typical entry would be:
</p>
<div class="example">
<pre class="example-preformatted">#ifdef ENABLE_FOOBAR
	[GNUTLS_EXTENSION_FOOBAR] = &amp;ext_mod_foobar,
#endif
</pre></div>

<p>Also for every extension you need to create an <code class="code">hello_ext_entry_st</code>
that describes the extension. This structure is placed in the designated
c file for your extension and its name is used in the registration entry
as depicted above.
</p>
<p>The structure of <code class="code">hello_ext_entry_st</code> is as follows:
</p><div class="example">
<pre class="example-preformatted">  const hello_ext_entry_st ext_mod_foobar = {
    .name = &quot;FOOBAR&quot;,
    .tls_id = 255,
    .gid = GNUTLS_EXTENSION_FOOBAR,
    .parse_type = GNUTLS_EXT_TLS,
    .validity = GNUTLS_EXT_FLAG_CLIENT_HELLO |
	GNUTLS_EXT_FLAG_TLS12_SERVER_HELLO |
	GNUTLS_EXT_FLAG_TLS13_SERVER_HELLO |
	GNUTLS_EXT_FLAG_TLS,
    .recv_func = _gnutls_foobar_recv_params,
    .send_func = _gnutls_foobar_send_params,
    .pack_func = _gnutls_foobar_pack,
    .unpack_func = _gnutls_foobar_unpack,
    .deinit_func = _gnutls_foobar_deinit,
    .cannot_be_overriden = 1
  };
</pre></div>

<p>The GNUTLS_EXTENSION_FOOBAR is the identifier that you&rsquo;ve added to
<code class="code">gnutls_int.h</code> earlier. The <code class="code">.tls_id</code> should contain the number
that IANA has assigned to this extension, or an unassigned number of your
choice if this is an unregistered extension. In the rest of this structure
you specify the functions to handle the extension data. The <code class="code">receive</code> function
will be called upon reception of the data and will be used to parse or
interpret the extension data. The <code class="code">send</code> function will be called prior to
sending the extension data on the wire and will be used to format the data
such that it can be send over the wire. The <code class="code">pack</code> and <code class="code">unpack</code>
functions will be used to prepare the data for storage in case of session resumption
(and vice versa). The <code class="code">deinit</code> function will be called to deinitialize
the extension&rsquo;s private parameters, if any.
</p>
<p>Look at <code class="code">gnutls_ext_parse_type_t</code> and <code class="code">gnutls_ext_flags_t</code> for a complete
list of available flags.
</p>
<p>Note that the conditional <code class="code">ENABLE_FOOBAR</code> definition should only be
used if step 1 with the <code class="code">configure</code> options has taken place.
</p>
<h4 class="subsubheading" id="Add-new-files-that-implement-the-hello-extension_002e"><span>Add new files that implement the hello extension.<a class="copiable-link" href="#Add-new-files-that-implement-the-hello-extension_002e"> &para;</a></span></h4>

<p>To keep things structured every extension should have its own files. The
functions that you should (at least) add are those referenced in the struct
from the previous step. Use descriptive file names such as <code class="code">lib/ext/foobar.c</code>
and for the corresponding header <code class="code">lib/ext/foobar.h</code>.
As a starter, you could add this:
</p>
<div class="example">
<pre class="example-preformatted">int
_gnutls_foobar_recv_params (gnutls_session_t session, const uint8_t * data,
                     size_t data_size)
{
  return 0;
}

int
_gnutls_foobar_send_params (gnutls_session_t session, gnutls_buffer_st* data)
{
  return 0;
}

int
_gnutls_foobar_pack (extension_priv_data_t epriv, gnutls_buffer_st * ps)
{
   /* Append the extension's internal state to buffer */
   return 0;
}

int
_gnutls_foobar_unpack (gnutls_buffer_st * ps, extension_priv_data_t * epriv)
{
   /* Read the internal state from buffer */
   return 0;
}
</pre></div>

<p>The <code class="code">_gnutls_foobar_recv_params</code> function is responsible for
parsing incoming extension data (both in the client and server).
</p>
<p>The <code class="code">_gnutls_foobar_send_params</code> function is responsible for
formatting extension data such that it can be send over the wire (both in
the client and server). It should append data to provided buffer and
return a positive (or zero) number on success or a negative error code.
Previous to 3.6.0 versions of GnuTLS required that function to return the
number of bytes that were written. If zero is returned and no bytes are
appended the extension will not be sent. If a zero byte extension is to
be sent this function must return <code class="code">GNUTLS_E_INT_RET_0</code>.
</p>
<p>If you receive length fields that don&rsquo;t match, return
<code class="code">GNUTLS_E_UNEXPECTED_PACKET_LENGTH</code>.  If you receive invalid
data, return <code class="code">GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER</code>.  You can use
other error codes from the list in <a class="ref" href="#Error-codes">Error Codes and Descriptions</a>. Return 0 on success.
</p>
<p>An extension typically stores private information in the <code class="code">session</code>
data for later usage. That can be done using the functions
<code class="code">_gnutls_hello_ext_set_datum</code> and
<code class="code">_gnutls_hello_ext_get_datum</code>. You can check simple examples
at <code class="code">lib/ext/max_record.c</code> and <code class="code">lib/ext/server_name.c</code> extensions.
That private information can be saved and restored across session
resumption if the following functions are set:
</p>
<p>The <code class="code">_gnutls_foobar_pack</code> function is responsible for packing
internal extension data to save them in the session resumption storage.
</p>
<p>The <code class="code">_gnutls_foobar_unpack</code> function is responsible for
restoring session data from the session resumption storage.
</p>
<p>When the internal data is stored using the <code class="code">_gnutls_hello_ext_set_datum</code>,
then you can rely on the default pack and unpack functions:
<code class="code">_gnutls_hello_ext_default_pack</code> and
<code class="code">_gnutls_hello_ext_default_unpack</code>.
</p>
<p>Recall that both for the client and server, the send and receive
functions most likely will need to do different things
depending on which mode they are in. It may be useful to make this
distinction explicit in the code. Thus, for example, a better
template than above would be:
</p>
<div class="example">
<pre class="example-preformatted">int
_gnutls_foobar_recv_params (gnutls_session_t session,
                            const uint8_t * data,
                            size_t data_size)
{
  if (session-&gt;security_parameters.entity == GNUTLS_CLIENT)
    return foobar_recv_client (session, data, data_size);
  else
    return foobar_recv_server (session, data, data_size);
}

int
_gnutls_foobar_send_params (gnutls_session_t session,
                            gnutls_buffer_st * data)
{
  if (session-&gt;security_parameters.entity == GNUTLS_CLIENT)
    return foobar_send_client (session, data);
  else
    return foobar_send_server (session, data);
}
</pre></div>

<p>The functions used would be declared as <code class="code">static</code> functions, of
the appropriate prototype, in the same file.
</p>
<p>When adding the new extension files, you&rsquo;ll need to add them to <code class="code">lib/ext/Makefile.am</code>
as well, for example:
</p>
<div class="example">
<pre class="example-preformatted">if ENABLE_FOOBAR
libgnutls_ext_la_SOURCES += ext/foobar.c ext/foobar.h
endif
</pre></div>

<h4 class="subsubheading" id="Add-API-functions-to-use-the-extension_002e"><span>Add API functions to use the extension.<a class="copiable-link" href="#Add-API-functions-to-use-the-extension_002e"> &para;</a></span></h4>

<p>It might be desirable to allow users of the extension to
request the use of the extension, or set extension specific data.
This can be implemented by adding extension specific function calls
that can be added to <code class="code">includes/gnutls/gnutls.h</code>,
as long as the LGPLv2.1+ applies.
The implementation of these functions should lie in the <code class="code">lib/ext/foobar.c</code> file.
</p>
<p>To make the API available in the shared library you need to add the added
symbols in <code class="code">lib/libgnutls.map</code>, so that the symbols are exported properly.
</p>
<p>When writing GTK-DOC style documentation for your new APIs, don&rsquo;t
forget to add <code class="code">Since:</code> tags to indicate the GnuTLS version the
API was introduced in.
</p>
<h4 class="subheading" id="Adding-a-new-Supplemental-Data-Handshake-Message"><span>Adding a new Supplemental Data Handshake Message<a class="copiable-link" href="#Adding-a-new-Supplemental-Data-Handshake-Message"> &para;</a></span></h4>

<p>TLS handshake extensions allow to send so called supplemental data
handshake messages [<a class="ref" href="#RFC4680">RFC4680</a>]. This short section explains how to
implement a supplemental data handshake message for a given TLS extension.
</p>
<p>First of all, modify your extension <code class="code">foobar</code> in the way, to instruct
the handshake process to send and receive supplemental data, as shown below.
</p>
<div class="example">
<pre class="example-preformatted">int
_gnutls_foobar_recv_params (gnutls_session_t session, const opaque * data,
                                 size_t _data_size)
{
   ...
   gnutls_supplemental_recv(session, 1);
   ...
}

int
_gnutls_foobar_send_params (gnutls_session_t session, gnutls_buffer_st *extdata)
{
   ...
   gnutls_supplemental_send(session, 1);
   ...
}
</pre></div>

<p>Furthermore you&rsquo;ll need two new functions <code class="code">_foobar_supp_recv_params</code>
and <code class="code">_foobar_supp_send_params</code>, which must conform to the following
prototypes.
</p>
<div class="example">
<pre class="example-preformatted">typedef int (*gnutls_supp_recv_func)(gnutls_session_t session,
                                     const unsigned char *data,
                                     size_t data_size);
typedef int (*gnutls_supp_send_func)(gnutls_session_t session,
                                     gnutls_buffer_t buf);
</pre></div>

<p>The following example code shows how to send a
&ldquo;Hello World&rdquo; string in the supplemental data handshake message.
</p>
<div class="example">
<pre class="example-preformatted">int
_foobar_supp_recv_params(gnutls_session_t session, const opaque *data, size_t _data_size)
{
   uint8_t len = _data_size;
   unsigned char *msg;

   msg = gnutls_malloc(len);
   if (msg == NULL) return GNUTLS_E_MEMORY_ERROR;

   memcpy(msg, data, len);
   msg[len]='\0';

   /* do something with msg */
   gnutls_free(msg);

   return len;
}

int
_foobar_supp_send_params(gnutls_session_t session, gnutls_buffer_t buf)
{
   unsigned char *msg = &quot;hello world&quot;;
   int len = strlen(msg);

   if (gnutls_buffer_append_data(buf, msg, len) &lt; 0)
       abort();

   return len;
}
</pre></div>

<p>Afterwards, register the new supplemental data using <a class="ref" href="#gnutls_005fsession_005fsupplemental_005fregister">gnutls_session_supplemental_register</a>,
or <a class="ref" href="#gnutls_005fsupplemental_005fregister">gnutls_supplemental_register</a> at some point in your program.
</p>
<hr>
</div>
<div class="section-level-extent" id="Cryptographic-Backend">
<div class="nav-panel">
<p>
Next: <a href="#Random-Number-Generators_002dinternals" accesskey="n" rel="next">Random Number Generators</a>, Previous: <a href="#TLS-Hello-Extension-Handling" accesskey="p" rel="prev">TLS Extension Handling</a>, Up: <a href="#Internal-architecture-of-GnuTLS" accesskey="u" rel="up">Internal Architecture of GnuTLS</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Cryptographic-Backend-1"><span>11.5 Cryptographic Backend<a class="copiable-link" href="#Cryptographic-Backend-1"> &para;</a></span></h3>

<p>Today most new processors, either for embedded or desktop systems
include either instructions  intended to speed up cryptographic operations,
or a co-processor with cryptographic capabilities. Taking advantage of
those is a challenging task for every cryptographic  application or
library. GnuTLS handles the cryptographic provider in a modular
way, following a layered approach to access
cryptographic operations as in <a class="ref" href="#fig_002dcrypto_002dlayers">Figure 11.4</a>.
</p>
<div class="float" id="fig_002dcrypto_002dlayers">
<img class="image" src="gnutls-crypto-layers.png" alt="gnutls-crypto-layers">
<div class="caption"><p><strong class="strong">Figure 11.4: </strong>GnuTLS cryptographic back-end design.</p></div></div>
<p>The TLS layer uses a cryptographic provider layer, that will in turn either
use the default crypto provider &ndash; a software crypto library, or use an external
crypto provider, if available in the local system. The reason of handling
the external cryptographic provider in GnuTLS and not delegating it to
the cryptographic libraries, is that none of the supported cryptographic
libraries support <code class="code">/dev/crypto</code> or CPU-optimized cryptography in
an efficient way.
</p>
<h4 class="subheading" id="Cryptographic-library-layer"><span>Cryptographic library layer<a class="copiable-link" href="#Cryptographic-library-layer"> &para;</a></span></h4>
<p>The Cryptographic library layer, currently supports only
libnettle. Older versions of GnuTLS used to support libgcrypt,
but it was switched with nettle mainly for performance reasons<a class="footnote" id="DOCF24" href="#FOOT24"><sup>24</sup></a>
and secondary because it is a simpler library to use.
In the future other cryptographic libraries might be supported as well.
</p>
<h4 class="subheading" id="External-cryptography-provider"><span>External cryptography provider<a class="copiable-link" href="#External-cryptography-provider"> &para;</a></span></h4>
<p>Systems that include a cryptographic co-processor, typically come with
kernel drivers to utilize the operations from software. For this reason
GnuTLS provides a layer where each individual algorithm used can be replaced
by another implementation, i.e., the one provided by the driver. The
FreeBSD, OpenBSD and Linux kernels<a class="footnote" id="DOCF25" href="#FOOT25"><sup>25</sup></a> include already
a number of hardware assisted implementations, and also provide an interface
to access them, called <code class="code">/dev/crypto</code>.
GnuTLS will take advantage of this interface if compiled with special
options. That is because in most systems where hardware-assisted
cryptographic operations are not available, using this interface might
actually harm performance.
</p>
<p>In systems that include cryptographic instructions with the CPU&rsquo;s
instructions set, using the kernel interface will introduce an
unneeded layer. For this reason GnuTLS includes such optimizations
found in popular processors such as the AES-NI or VIA PADLOCK instruction sets.
This is achieved using a mechanism that detects CPU capabilities and
overrides parts of crypto back-end at runtime.
The next section discusses the registration of a detected algorithm
optimization. For more information please consult the <abbr class="acronym">GnuTLS</abbr>
source code in <code class="code">lib/accelerated/</code>.
</p>
<h4 class="subsubheading" id="Overriding-specific-algorithms"><span>Overriding specific algorithms<a class="copiable-link" href="#Overriding-specific-algorithms"> &para;</a></span></h4>
<p>When an optimized implementation of a single algorithm is available,
say a hardware assisted version of <abbr class="acronym">AES-CBC</abbr> then the
following functions, from <code class="code">crypto.h</code>, can
be used to register those algorithms.
</p>
<ul class="itemize mark-bullet">
<li><a class="ref" href="#gnutls_005fcrypto_005fregister_005fcipher">gnutls_crypto_register_cipher</a>:
To register a cipher algorithm.

</li><li><a class="ref" href="#gnutls_005fcrypto_005fregister_005faead_005fcipher">gnutls_crypto_register_aead_cipher</a>:
To register an AEAD cipher algorithm.

</li><li><a class="ref" href="#gnutls_005fcrypto_005fregister_005fmac">gnutls_crypto_register_mac</a>:
To register a MAC algorithm.

</li><li><a class="ref" href="#gnutls_005fcrypto_005fregister_005fdigest">gnutls_crypto_register_digest</a>:
To register a hash algorithm.

</li></ul>

<p>Those registration functions will only replace the specified algorithm
and leave the rest of subsystem intact.
</p>

<h4 class="subheading" id="Protecting-keys-through-isolation"><span>Protecting keys through isolation<a class="copiable-link" href="#Protecting-keys-through-isolation"> &para;</a></span></h4>

<p>For asymmetric or public keys, GnuTLS supports PKCS #11 which allows
operation without access to long term keys, in addition to CPU offloading.
For more information see <a class="ref" href="#Hardware-security-modules-and-abstract-key-types">Abstract key types and Hardware security modules</a>.
</p>

<hr>
</div>
<div class="section-level-extent" id="Random-Number-Generators_002dinternals">
<div class="nav-panel">
<p>
Next: <a href="#FIPS140_002d2-mode" accesskey="n" rel="next">FIPS140-2 mode</a>, Previous: <a href="#Cryptographic-Backend" accesskey="p" rel="prev">Cryptographic Backend</a>, Up: <a href="#Internal-architecture-of-GnuTLS" accesskey="u" rel="up">Internal Architecture of GnuTLS</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Random-Number-Generators"><span>11.6 Random Number Generators<a class="copiable-link" href="#Random-Number-Generators"> &para;</a></span></h3>

<h4 class="subheading" id="About-the-generators"><span>About the generators<a class="copiable-link" href="#About-the-generators"> &para;</a></span></h4>

<p>GnuTLS provides two random generators. The default, and the AES-DRBG random
generator which is only used when the library is compiled with support for
FIPS140-2 and the system is in FIPS140-2 mode.
</p>
<h4 class="subheading" id="The-default-generator-_002d-inner-workings"><span>The default generator - inner workings<a class="copiable-link" href="#The-default-generator-_002d-inner-workings"> &para;</a></span></h4>

<p>The random number generator levels in <code class="code">gnutls_rnd_level_t</code> map to two CHACHA-based random generators which
are initially seeded using the OS random device, e.g., <code class="code">/dev/urandom</code>
or <code class="code">getrandom()</code>. These random generators are unique per thread, and
are automatically re-seeded when a fork is detected.
</p>
<p>The reason the CHACHA cipher was selected for the GnuTLS&rsquo; PRNG is the fact
that CHACHA is considered a secure and fast stream cipher, and is already
defined for use in TLS protocol. As such, the utilization of it would
not stress the CPU caches, and would allow for better performance on busy
servers, irrespective of their architecture (e.g., even if AES is not
available with an optimized instruction set).
</p>
<p>The generators are unique per thread to allow lock-free operation. That
induces a cost of around 140-bytes for the state of the generators per
thread, on threads that would utilize <a class="ref" href="#gnutls_005frnd">gnutls_rnd</a>. At the same time
it allows fast and lock-free access to the generators. The lock-free access
benefits servers which utilize more than 4 threads, while imposes no cost on
single threaded processes.
</p>
<p>On the first call to <a class="ref" href="#gnutls_005frnd">gnutls_rnd</a> the generators are seeded with two independent
keys obtained from the OS random device. Their seed is used to output a fixed amount
of bytes before re-seeding; the number of bytes output varies per generator.
</p>
<p>One generator is dedicated for the <code class="code">GNUTLS_RND_NONCE</code> level, and the
second is shared for the <code class="code">GNUTLS_RND_KEY</code> and <code class="code">GNUTLS_RND_RANDOM</code>
levels. For the rest of this section we refer to the first as the nonce
generator and the second as the key generator.
</p>
<p>The nonce generator will reseed after outputting a fixed amount of bytes
(typically few megabytes), or after few hours of operation without reaching
the limit has passed. It is being re-seed using
the key generator to obtain a new key for the CHACHA cipher, which is mixed
with its old one.
</p>
<p>Similarly, the key generator, will also re-seed after a fixed amount
of bytes is generated (typically less than the nonce), and will also re-seed
based on time, i.e., after few hours of operation without reaching the limit
for a re-seed. For its re-seed it mixes mixes data obtained from the OS random
device with the previous key.
</p>
<p>Although the key generator used to provide data for the <code class="code">GNUTLS_RND_RANDOM</code>
and <code class="code">GNUTLS_RND_KEY</code> levels is identical, when used with the <code class="code">GNUTLS_RND_KEY</code> level
a re-key of the PRNG using its own output, is additionally performed. That ensures that
the recovery of the PRNG state will not be sufficient to recover previously generated values.
</p>

<h4 class="subheading" id="The-AES_002dDRBG-generator-_002d-inner-workings"><span>The AES-DRBG generator - inner workings<a class="copiable-link" href="#The-AES_002dDRBG-generator-_002d-inner-workings"> &para;</a></span></h4>

<p>Similar with the default generator, the random number generator levels in <code class="code">gnutls_rnd_level_t</code> map to two
AES-DRBG random generators which are initially seeded using the OS random device,
e.g., <code class="code">/dev/urandom</code> or <code class="code">getrandom()</code>. These random generators are
unique per thread, and are automatically re-seeded when a fork is detected.
</p>
<p>The AES-DRBG generator is based on the AES cipher in counter mode and is
re-seeded after a fixed amount of bytes are generated.
</p>

<h4 class="subheading" id="Defense-against-PRNG-attacks"><span>Defense against PRNG attacks<a class="copiable-link" href="#Defense-against-PRNG-attacks"> &para;</a></span></h4>

<p>This section describes the counter-measures available in the Pseudo-random number generator (PRNG)
of GnuTLS for known attacks as described in [<a class="ref" href="#PRNGATTACKS">PRNGATTACKS</a>]. Note that, the attacks on a PRNG such as
state-compromise, assume a quite powerful adversary which has in practice
access to the PRNG state.
</p>
<h4 class="subsubheading" id="Cryptanalytic"><span>Cryptanalytic<a class="copiable-link" href="#Cryptanalytic"> &para;</a></span></h4>

<p>To defend against cryptanalytic attacks GnuTLS&rsquo; PRNG is a stream cipher
designed to defend against the same attacks. As such, GnuTLS&rsquo; PRNG strength
with regards to this attack relies on the underlying crypto block,
which at the time of writing is CHACHA. That is easily replaceable in
the future if attacks are found to be possible in that cipher.
</p>
<h4 class="subsubheading" id="Input_002dbased-attacks"><span>Input-based attacks<a class="copiable-link" href="#Input_002dbased-attacks"> &para;</a></span></h4>

<p>These attacks assume that the attacker can influence the input that is used
to form the state of the PRNG. To counter these attacks GnuTLS does not
gather input from the system environment but rather relies on the OS
provided random generator. That is the <code class="code">/dev/urandom</code> or
<code class="code">getentropy</code>/<code class="code">getrandom</code> system calls. As such, GnuTLS&rsquo; PRNG
is as strong as the system random generator can assure with regards to
input-based attacks.
</p>
<h4 class="subsubheading" id="State_002dcompromise_003a-Backtracking"><span>State-compromise: Backtracking<a class="copiable-link" href="#State_002dcompromise_003a-Backtracking"> &para;</a></span></h4>

<p>A backtracking attack, assumes that an adversary obtains at some point of time
access to the generator state, and wants to recover past bytes. As the
GnuTLS generator is fine-tuned to provide multiple levels, such an attack
mainly concerns levels <code class="code">GNUTLS_RND_RANDOM</code> and <code class="code">GNUTLS_RND_KEY</code>,
since <code class="code">GNUTLS_RND_NONCE</code> is intended to output non-secret data.
The <code class="code">GNUTLS_RND_RANDOM</code> generator at the time of writing can output
2MB prior to being re-seeded thus this is its upper bound for previously
generated data recovered using this attack. That assumes that the state
of the operating system random generator is unknown to the attacker, and we carry that
assumption on the next paragraphs. The usage of <code class="code">GNUTLS_RND_KEY</code> level
ensures that no backtracking is possible for all output data, by re-keying
the PRNG using its own output.
</p>
<p>Such an attack reflects the real world scenario where application&rsquo;s memory is
temporarily compromised, while the kernel&rsquo;s memory is inaccessible.
</p>
<h4 class="subsubheading" id="State_002dcompromise_003a-Permanent-Compromise-Attack"><span>State-compromise: Permanent Compromise Attack<a class="copiable-link" href="#State_002dcompromise_003a-Permanent-Compromise-Attack"> &para;</a></span></h4>

<p>A permanent compromise attack implies that once an attacker compromises the
state of GnuTLS&rsquo; random generator at a specific time, future and past
outputs from the generator are compromised. For past outputs the
previous paragraph applies. For future outputs, both the <code class="code">GNUTLS_RND_RANDOM</code>
and the <code class="code">GNUTLS_RND_KEY</code> will recover after 2MB of data have been generated
or few hours have passed (two at the time of writing). Similarly the <code class="code">GNUTLS_RND_NONCE</code>
level generator will recover after several megabytes of output is generated,
or its re-key time is reached.
</p>
<h4 class="subsubheading" id="State_002dcompromise_003a-Iterative-guessing"><span>State-compromise: Iterative guessing<a class="copiable-link" href="#State_002dcompromise_003a-Iterative-guessing"> &para;</a></span></h4>

<p>This attack assumes that after an attacker obtained the PRNG state
at some point, is able to recover the state at a later time by observing
outputs of the PRNG. That is countered by switching the key to generators
using a combination of a fresh key and the old one (using XOR), at
re-seed time. All levels are immune to such attack after a re-seed.
</p>
<h4 class="subsubheading" id="State_002dcompromise_003a-Meet_002din_002dthe_002dMiddle"><span>State-compromise: Meet-in-the-Middle<a class="copiable-link" href="#State_002dcompromise_003a-Meet_002din_002dthe_002dMiddle"> &para;</a></span></h4>

<p>This attack assumes that the attacker obtained the PRNG state at
two distinct times, and being able to recover the state at the third time
after observing the output of the PRNG. Given the approach described
on the above paragraph, all levels are immune to such attack.
</p>
<hr>
</div>
<div class="section-level-extent" id="FIPS140_002d2-mode">
<div class="nav-panel">
<p>
Previous: <a href="#Random-Number-Generators_002dinternals" accesskey="p" rel="prev">Random Number Generators</a>, Up: <a href="#Internal-architecture-of-GnuTLS" accesskey="u" rel="up">Internal Architecture of GnuTLS</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="FIPS140_002d2-mode-1"><span>11.7 FIPS140-2 mode<a class="copiable-link" href="#FIPS140_002d2-mode-1"> &para;</a></span></h3>

<p>GnuTLS can operate in a special mode for FIPS140-2. That mode of operation
is for the conformance to NIST&rsquo;s FIPS140-2 publication, which consists of policies
for cryptographic modules (such as software libraries). Its implementation in
GnuTLS is designed for Red Hat Enterprise Linux, and can only be enabled
when the library is explicitly compiled with the &rsquo;&ndash;enable-fips140-mode&rsquo;
configure option.
</p>
<p>There are two distinct library states with regard to FIPS140-2: the FIPS140-2
mode is <em class="emph">installed</em> if <code class="code">/etc/system-fips</code> is present, and the
FIPS140-2 mode is <em class="emph">enabled</em> if <code class="code">/proc/sys/crypto/fips_enabled</code>
contains &rsquo;1&rsquo;, which is typically set with the &ldquo;fips=1&rdquo; kernel command line
option.
</p>
<p>When the FIPS140-2 mode is installed, the operation of the library is modified
as follows.
</p>
<ul class="itemize mark-bullet">
<li>The random generator used switches to DRBG-AES
</li><li>The integrity of the GnuTLS and dependent libraries is checked on startup
</li><li>Algorithm self-tests are run on library load
</li></ul>

<p>When the FIPS140-2 mode is enabled, The operation of the library is in addition
modified as follows.
</p>
<ul class="itemize mark-bullet">
<li>Only approved by FIPS140-2 algorithms are enabled
</li><li>Only approved by FIPS140-2 key lengths are allowed for key generation
</li><li>Any cryptographic operation will be refused if any of the self-tests failed
</li></ul>


<p>There are also few environment variables which modify that operation. The
environment variable <code class="code">GNUTLS_SKIP_FIPS_INTEGRITY_CHECKS</code> will disable
the library integrity tests on startup, and the variable
<code class="code">GNUTLS_FORCE_FIPS_MODE</code> can be set to force a value from
<a class="ref" href="#gnutls_005ffips_005fmode_005ft">Figure 11.5</a>, i.e., &rsquo;1&rsquo; will enable the FIPS140-2
mode, while &rsquo;0&rsquo; will disable it.
</p>
<p>The integrity checks for the dependent libraries and GnuTLS are performed
using &rsquo;.hmac&rsquo; files which are present at the same path as the library. The
key for the operations can be provided on compile-time with the configure
option &rsquo;&ndash;with-fips140-key&rsquo;. The MAC algorithm used is HMAC-SHA256.
</p>
<p>On runtime an application can verify whether the library is in FIPS140-2
mode using the <a class="ref" href="#gnutls_005ffips140_005fmode_005fenabled">gnutls_fips140_mode_enabled</a> function.
</p>
<h4 class="subheading" id="Relaxing-FIPS140_002d2-requirements"><span>Relaxing FIPS140-2 requirements<a class="copiable-link" href="#Relaxing-FIPS140_002d2-requirements"> &para;</a></span></h4>

<p>The library by default operates in a strict enforcing mode, ensuring that
all constraints imposed by the FIPS140-2 specification are enforced. However
the application can relax these requirements via <a class="ref" href="#gnutls_005ffips140_005fset_005fmode">gnutls_fips140_set_mode</a>
which can switch to alternative modes as in <a class="ref" href="#gnutls_005ffips_005fmode_005ft">Figure 11.5</a>.
</p>
<div class="float" id="gnutls_005ffips_005fmode_005ft">


<dl class="table">
<dt><code class="code">GNUTLS_FIPS140_DISABLED</code></dt>
<dd><p>The FIPS140-2 mode is disabled.
</p></dd>
<dt><code class="code">GNUTLS_FIPS140_STRICT</code></dt>
<dd><p>The default mode; all forbidden operations will cause an
operation failure via error code.
</p></dd>
<dt><code class="code">GNUTLS_FIPS140_SELFTESTS</code></dt>
<dd><p>A transient state during library initialization. That state
cannot be set or seen by applications.
</p></dd>
<dt><code class="code">GNUTLS_FIPS140_LAX</code></dt>
<dd><p>The library still uses the FIPS140-2 relevant algorithms but all
forbidden by FIPS140-2 operations are allowed; this is useful when the
application is aware of the followed security policy, and needs
to utilize disallowed operations for other reasons (e.g., compatibility).
</p></dd>
<dt><code class="code">GNUTLS_FIPS140_LOG</code></dt>
<dd><p>Similarly to <code class="code">GNUTLS_FIPS140_LAX</code> , it allows forbidden operations; any use of them results
to a message to the audit callback functions.
</p></dd>
</dl>
<div class="caption"><p><strong class="strong">Figure 11.5: </strong>The <code class="code">gnutls_fips_mode_t</code> enumeration.</p></div></div>
<p>The intention of this API is to be used by applications which may run in
FIPS140-2 mode, while they utilize few algorithms not in the allowed set,
e.g., for non-security related purposes. In these cases applications should
wrap the non-compliant code within blocks like the following.
</p>
<div class="example">
<pre class="example-preformatted">GNUTLS_FIPS140_SET_LAX_MODE();

_gnutls_hash_fast(GNUTLS_DIG_MD5, buffer, sizeof(buffer), output);

GNUTLS_FIPS140_SET_STRICT_MODE();
</pre></div>

<p>The <code class="code">GNUTLS_FIPS140_SET_LAX_MODE</code> and
<code class="code">GNUTLS_FIPS140_SET_STRICT_MODE</code> are macros to simplify the following
sequence of calls.
</p>
<div class="example">
<pre class="example-preformatted">if (gnutls_fips140_mode_enabled())
  gnutls_fips140_set_mode(GNUTLS_FIPS140_LAX, GNUTLS_FIPS140_SET_MODE_THREAD);

_gnutls_hash_fast(GNUTLS_DIG_MD5, buffer, sizeof(buffer), output);

if (gnutls_fips140_mode_enabled())
  gnutls_fips140_set_mode(GNUTLS_FIPS140_STRICT, GNUTLS_FIPS140_SET_MODE_THREAD);
</pre></div>

<p>The reason of the <code class="code">GNUTLS_FIPS140_SET_MODE_THREAD</code> flag in the
previous calls is to localize the change in the mode. Note also, that
such a block has no effect when the library is not operating
under FIPS140-2 mode, and thus it can be considered a no-op.
</p>
<p>Applications could also switch FIPS140-2 mode explicitly off, by calling
</p><div class="example">
<pre class="example-preformatted">gnutls_fips140_set_mode(GNUTLS_FIPS140_LAX, 0);
</pre></div>

<h4 class="subheading" id="Service-indicator"><span>Service indicator<a class="copiable-link" href="#Service-indicator"> &para;</a></span></h4>

<p>The above restrictions may not cover all the requirements in every
usage context, and as the FIPS140 standard evolves (like FIPS140-3),
GnuTLS may not be able to add new restrictions without breaking
compatibility.
</p>
<p>Therefore an additional set of API functions is provided to
communicate with the user whether any approved mode of operations is
performed within a given context.
</p>
<dl class="table">
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005ffips140_005fcontext_005finit">gnutls_fips140_context_init</a> (gnutls_fips140_context_t * <var class="var">context</var>)</code></dt>
<dt><code class="code"><var class="var">void</var> <a class="ref" href="#gnutls_005ffips140_005fcontext_005fdeinit">gnutls_fips140_context_deinit</a> (gnutls_fips140_context_t <var class="var">context</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005ffips140_005fpush_005fcontext">gnutls_fips140_push_context</a> (gnutls_fips140_context_t <var class="var">context</var>)</code></dt>
<dt><code class="code"><var class="var">int</var> <a class="ref" href="#gnutls_005ffips140_005fpop_005fcontext">gnutls_fips140_pop_context</a> ( <var class="var">void</var>)</code></dt>
</dl>

<p>The <code class="code">gnutls_fips140_context_t</code> represents the FIPS140-2 mode of
operation.  It can be attached to the current execution thread with
<a class="ref" href="#gnutls_005ffips140_005fpush_005fcontext">gnutls_fips140_push_context</a> and its internal state will be
updated until it is detached with
<a class="ref" href="#gnutls_005ffips140_005fpop_005fcontext">gnutls_fips140_pop_context</a>.  Afterwards
<a class="ref" href="#gnutls_005ffips140_005fget_005foperation_005fstate">gnutls_fips140_get_operation_state</a> allows the user
to examine whether any approved (or non-approved) security function is
invoked.
</p>




<dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ffips140_005fget_005foperation_005fstate"><span class="category-def">Function: </span><span><code class="def-type">gnutls_fips140_operation_state_t</code> <strong class="def-name">gnutls_fips140_get_operation_state</strong> <code class="def-code-arguments">(gnutls_fips140_context_t <var class="var">context</var>)</code><a class="copiable-link" href="#index-gnutls_005ffips140_005fget_005foperation_005fstate"> &para;</a></span></dt>
<dd><p><var class="var">context</var>: a <code class="code">gnutls_fips140_context_t</code> 
</p>
<p>Get the previous operation state of  <code class="code">context</code> in terms of FIPS.
</p>
<p><strong class="strong">Returns:</strong> a <code class="code">gnutls_fips140_operation_state_t</code> 
</p>
<p><strong class="strong">Since:</strong> 3.7.3
</p></dd></dl>


<hr>
</div>
</div>
<div class="appendix-level-extent" id="Upgrading-from-previous-versions">
<div class="nav-panel">
<p>
Next: <a href="#Support" accesskey="n" rel="next">Support</a>, Previous: <a href="#Internal-architecture-of-GnuTLS" accesskey="p" rel="prev">Internal Architecture of GnuTLS</a>, Up: <a href="#Top" accesskey="u" rel="up">GnuTLS</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h2 class="appendix" id="Upgrading-from-previous-versions-1"><span>Appendix A Upgrading from previous versions<a class="copiable-link" href="#Upgrading-from-previous-versions-1"> &para;</a></span></h2>
<a class="index-entry-id" id="index-upgrading"></a>

<p>The GnuTLS library typically maintains binary and source code compatibility
across versions. The releases that have the major version increased
break binary compatibility but source compatibility is provided.
This section lists exceptional cases where changes to existing code are
required due to library changes.
</p>
<h3 class="heading" id="Upgrading-to-2_002e12_002ex-from-previous-versions"><span>Upgrading to 2.12.x from previous versions<a class="copiable-link" href="#Upgrading-to-2_002e12_002ex-from-previous-versions"> &para;</a></span></h3>

<p>GnuTLS 2.12.x is binary compatible with previous versions but changes the
semantics of <code class="code">gnutls_transport_set_lowat</code>, which might cause breakage
in applications that relied on its default value be 1. Two fixes
are proposed:
</p><ul class="itemize mark-bullet">
<li>Quick fix. Explicitly call <code class="code">gnutls_transport_set_lowat (session, 1);</code>
after <a class="ref" href="#gnutls_005finit">gnutls_init</a>.
</li><li>Long term fix. Because later versions of gnutls abolish the functionality 
of using the system call <code class="code">select</code> to check for gnutls pending data, the 
function <a class="ref" href="#gnutls_005frecord_005fcheck_005fpending">gnutls_record_check_pending</a> has to be used to achieve the same 
functionality as described in <a class="ref" href="#Asynchronous-operation">Asynchronous operation</a>.
</li></ul>

<h3 class="heading" id="Upgrading-to-3_002e0_002ex-from-2_002e12_002ex"><span>Upgrading to 3.0.x from 2.12.x<a class="copiable-link" href="#Upgrading-to-3_002e0_002ex-from-2_002e12_002ex"> &para;</a></span></h3>

<p>GnuTLS 3.0.x is source compatible with previous versions except for the functions
listed below.
</p>
<table class="multitable">
<thead><tr><th width="30%">Old function</th><th width="60%">Replacement</th></tr></thead>
<tbody><tr><td width="30%"><code class="code">gnutls_transport_set_lowat</code></td><td width="60%">To replace its functionality the function <a class="ref" href="#gnutls_005frecord_005fcheck_005fpending">gnutls_record_check_pending</a> has to be used,
as described in <a class="ref" href="#Asynchronous-operation">Asynchronous operation</a></td></tr>
<tr><td width="30%"><code class="code">gnutls_session_get_server_random</code>,
<code class="code">gnutls_session_get_client_random</code></td><td width="60%">They are replaced by the safer function <a class="ref" href="#gnutls_005fsession_005fget_005frandom">gnutls_session_get_random</a></td></tr>
<tr><td width="30%"><code class="code">gnutls_session_get_master_secret</code></td><td width="60%">Replaced by the keying material exporters discussed in <a class="ref" href="#Deriving-keys-for-other-applications_002fprotocols">Deriving keys for other applications/protocols</a></td></tr>
<tr><td width="30%"><code class="code">gnutls_transport_set_global_errno</code></td><td width="60%">Replaced by using the system&rsquo;s errno facility or <a class="ref" href="#gnutls_005ftransport_005fset_005ferrno">gnutls_transport_set_errno</a>.</td></tr>
<tr><td width="30%"><code class="code">gnutls_x509_privkey_verify_data</code></td><td width="60%">Replaced by <a class="ref" href="#gnutls_005fpubkey_005fverify_005fdata2">gnutls_pubkey_verify_data2</a>.</td></tr>
<tr><td width="30%"><code class="code">gnutls_certificate_verify_peers</code></td><td width="60%">Replaced by <a class="ref" href="#gnutls_005fcertificate_005fverify_005fpeers2">gnutls_certificate_verify_peers2</a>.</td></tr>
<tr><td width="30%"><code class="code">gnutls_psk_netconf_derive_key</code></td><td width="60%">Removed. The key derivation function was never standardized.</td></tr>
<tr><td width="30%"><code class="code">gnutls_session_set_finished_function</code></td><td width="60%">Removed.</td></tr>
<tr><td width="30%"><code class="code">gnutls_ext_register</code></td><td width="60%">Removed. Extension registration API is now internal to allow easier changes in the API.</td></tr>
<tr><td width="30%"><code class="code">gnutls_certificate_get_x509_crls</code>, <code class="code">gnutls_certificate_get_x509_cas</code></td><td width="60%">Removed to allow updating the internal structures. Replaced by <a class="ref" href="#gnutls_005fcertificate_005fget_005fissuer">gnutls_certificate_get_issuer</a>.</td></tr>
<tr><td width="30%"><code class="code">gnutls_certificate_get_openpgp_keyring</code></td><td width="60%">Removed.</td></tr>
<tr><td width="30%"><code class="code">gnutls_ia_</code></td><td width="60%">Removed. The inner application extensions were completely removed (they failed to be standardized).</td></tr>
</tbody>
</table>

<h3 class="heading" id="Upgrading-to-3_002e1_002ex-from-3_002e0_002ex"><span>Upgrading to 3.1.x from 3.0.x<a class="copiable-link" href="#Upgrading-to-3_002e1_002ex-from-3_002e0_002ex"> &para;</a></span></h3>

<p>GnuTLS 3.1.x is source and binary compatible with GnuTLS 3.0.x releases. Few
functions have been deprecated and are listed below.
</p>
<table class="multitable">
<thead><tr><th width="30%">Old function</th><th width="60%">Replacement</th></tr></thead>
<tbody><tr><td width="30%"><code class="code">gnutls_pubkey_verify_hash</code></td><td width="60%">The function <a class="ref" href="#gnutls_005fpubkey_005fverify_005fhash2">gnutls_pubkey_verify_hash2</a> is provided and
is functionally equivalent and safer to use.</td></tr>
<tr><td width="30%"><code class="code">gnutls_pubkey_verify_data</code></td><td width="60%">The function <a class="ref" href="#gnutls_005fpubkey_005fverify_005fdata2">gnutls_pubkey_verify_data2</a> is provided and
is functionally equivalent and safer to use.</td></tr>
</tbody>
</table>

<h3 class="heading" id="Upgrading-to-3_002e2_002ex-from-3_002e1_002ex"><span>Upgrading to 3.2.x from 3.1.x<a class="copiable-link" href="#Upgrading-to-3_002e2_002ex-from-3_002e1_002ex"> &para;</a></span></h3>

<p>GnuTLS 3.2.x is source and binary compatible with GnuTLS 3.1.x releases. Few
functions have been deprecated and are listed below.
</p>
<table class="multitable">
<thead><tr><th width="30%">Old function</th><th width="60%">Replacement</th></tr></thead>
<tbody><tr><td width="30%"><code class="code">gnutls_privkey_sign_raw_data</code></td><td width="60%">The function <a class="ref" href="#gnutls_005fprivkey_005fsign_005fhash">gnutls_privkey_sign_hash</a> is equivalent
when the flag <code class="code">GNUTLS_PRIVKEY_SIGN_FLAG_TLS1_RSA</code> is specified.</td></tr>
</tbody>
</table>

<h3 class="heading" id="Upgrading-to-3_002e3_002ex-from-3_002e2_002ex"><span>Upgrading to 3.3.x from 3.2.x<a class="copiable-link" href="#Upgrading-to-3_002e3_002ex-from-3_002e2_002ex"> &para;</a></span></h3>

<p>GnuTLS 3.3.x is source and binary compatible with GnuTLS 3.2.x releases;
however there few changes in semantics which are listed below.
</p>
<table class="multitable">
<thead><tr><th width="30%">Old function</th><th width="60%">Replacement</th></tr></thead>
<tbody><tr><td width="30%"><code class="code">gnutls_global_init</code></td><td width="60%">No longer required. The library is initialized using a constructor.</td></tr>
<tr><td width="30%"><code class="code">gnutls_global_deinit</code></td><td width="60%">No longer required. The library is deinitialized using a destructor.</td></tr>
</tbody>
</table>

<h3 class="heading" id="Upgrading-to-3_002e4_002ex-from-3_002e3_002ex"><span>Upgrading to 3.4.x from 3.3.x<a class="copiable-link" href="#Upgrading-to-3_002e4_002ex-from-3_002e3_002ex"> &para;</a></span></h3>

<p>GnuTLS 3.4.x is source compatible with GnuTLS 3.3.x releases;
however, several deprecated functions were removed, and are listed below.
</p>
<table class="multitable">
<thead><tr><th width="30%">Old function</th><th width="60%">Replacement</th></tr></thead>
<tbody><tr><td width="30%">Priority string &quot;NORMAL&quot; has been modified</td><td width="60%">The following string emulates the 3.3.x behavior &quot;NORMAL:+VERS-SSL3.0:+ARCFOUR-128:+DHE-DSS:+SIGN-DSA-SHA512:+SIGN-DSA-SHA256:+SIGN-DSA-SHA1&quot;</td></tr>
<tr><td width="30%"><code class="code">gnutls_certificate_client_set_retrieve_function</code>,
<code class="code">gnutls_certificate_server_set_retrieve_function</code></td><td width="60%"><a class="ref" href="#gnutls_005fcertificate_005fset_005fretrieve_005ffunction">gnutls_certificate_set_retrieve_function</a></td></tr>
<tr><td width="30%"><code class="code">gnutls_certificate_set_rsa_export_params</code>,
<code class="code">gnutls_rsa_export_get_modulus_bits</code>,
<code class="code">gnutls_rsa_export_get_pubkey</code>,
<code class="code">gnutls_rsa_params_cpy</code>,
<code class="code">gnutls_rsa_params_deinit</code>,
<code class="code">gnutls_rsa_params_export_pkcs1</code>,
<code class="code">gnutls_rsa_params_export_raw</code>,
<code class="code">gnutls_rsa_params_generate2</code>,
<code class="code">gnutls_rsa_params_import_pkcs1</code>,
<code class="code">gnutls_rsa_params_import_raw</code>,
<code class="code">gnutls_rsa_params_init</code></td><td width="60%">No replacement; the library does not support the RSA-EXPORT ciphersuites.</td></tr>
<tr><td width="30%"><code class="code">gnutls_pubkey_verify_hash</code>,</td><td width="60%"><a class="ref" href="#gnutls_005fpubkey_005fverify_005fhash2">gnutls_pubkey_verify_hash2</a>.</td></tr>
<tr><td width="30%"><code class="code">gnutls_pubkey_verify_data</code>,</td><td width="60%"><a class="ref" href="#gnutls_005fpubkey_005fverify_005fdata2">gnutls_pubkey_verify_data2</a>.</td></tr>
<tr><td width="30%"><code class="code">gnutls_x509_crt_get_verify_algorithm</code>,</td><td width="60%">No replacement; a similar function is <a class="ref" href="#gnutls_005fx509_005fcrt_005fget_005fsignature_005falgorithm">gnutls_x509_crt_get_signature_algorithm</a>.</td></tr>
<tr><td width="30%"><code class="code">gnutls_pubkey_get_verify_algorithm</code>,</td><td width="60%">No replacement; a similar function is <a class="ref" href="#gnutls_005fpubkey_005fget_005fpreferred_005fhash_005falgorithm">gnutls_pubkey_get_preferred_hash_algorithm</a>.</td></tr>
<tr><td width="30%"><code class="code">gnutls_certificate_type_set_priority</code>,
<code class="code">gnutls_cipher_set_priority</code>,
<code class="code">gnutls_compression_set_priority</code>,
<code class="code">gnutls_kx_set_priority</code>,
<code class="code">gnutls_mac_set_priority</code>,
<code class="code">gnutls_protocol_set_priority</code></td><td width="60%"><a class="ref" href="#gnutls_005fpriority_005fset_005fdirect">gnutls_priority_set_direct</a>.</td></tr>
<tr><td width="30%"><code class="code">gnutls_sign_callback_get</code>,
<code class="code">gnutls_sign_callback_set</code></td><td width="60%"><a class="ref" href="#gnutls_005fprivkey_005fimport_005fext3">gnutls_privkey_import_ext3</a></td></tr>
<tr><td width="30%"><code class="code">gnutls_x509_crt_verify_hash</code></td><td width="60%"><a class="ref" href="#gnutls_005fpubkey_005fverify_005fhash2">gnutls_pubkey_verify_hash2</a></td></tr>
<tr><td width="30%"><code class="code">gnutls_x509_crt_verify_data</code></td><td width="60%"><a class="ref" href="#gnutls_005fpubkey_005fverify_005fdata2">gnutls_pubkey_verify_data2</a></td></tr>
<tr><td width="30%"><code class="code">gnutls_privkey_sign_raw_data</code></td><td width="60%"><a class="ref" href="#gnutls_005fprivkey_005fsign_005fhash">gnutls_privkey_sign_hash</a> with the flag GNUTLS_PRIVKEY_SIGN_FLAG_TLS1_RSA</td></tr>
</tbody>
</table>

<h3 class="heading" id="Upgrading-to-3_002e6_002ex-from-3_002e5_002ex"><span>Upgrading to 3.6.x from 3.5.x<a class="copiable-link" href="#Upgrading-to-3_002e6_002ex-from-3_002e5_002ex"> &para;</a></span></h3>

<p>GnuTLS 3.6.x is source and binary compatible with GnuTLS 3.5.x releases;
however, there are minor differences, listed below.
</p>
<table class="multitable">
<thead><tr><th width="30%">Old functionality</th><th width="60%">Replacement</th></tr></thead>
<tbody><tr><td width="30%">The priority strings &quot;+COMP&quot; are a no-op</td><td width="60%">TLS compression is no longer available.</td></tr>
<tr><td width="30%">The SSL 3.0 protocol is a no-op</td><td width="60%">SSL 3.0 is no longer compiled in by default. It is a legacy protocol
which is completely eliminated from public internet. As such it was removed
to reduce the attack vector for applications using the library.</td></tr>
<tr><td width="30%">The hash function SHA2-224 is a no-op for TLS1.2</td><td width="60%">TLS 1.3 no longer uses SHA2-224, and it was never a widespread hash
algorithm. As such it was removed for simplicity.</td></tr>
<tr><td width="30%">The SRP key exchange accepted parameters outside the [<a class="ref" href="#TLSSRP">TLSSRP</a>] spec</td><td width="60%">The SRP key exchange is restricted to [<a class="ref" href="#TLSSRP">TLSSRP</a>] spec parameters
to protect clients from MitM attacks.</td></tr>
<tr><td width="30%">The compression-related functions are deprecated</td><td width="60%">No longer use <code class="code">gnutls_compression_get</code>,
<code class="code">gnutls_compression_get_name</code>, <code class="code">gnutls_compression_list</code>,
and <code class="code">gnutls_compression_get_id</code>.</td></tr>
<tr><td width="30%"><a class="ref" href="#gnutls_005fx509_005fcrt_005fsign">gnutls_x509_crt_sign</a>, <a class="ref" href="#gnutls_005fx509_005fcrl_005fsign">gnutls_x509_crl_sign</a>, <a class="ref" href="#gnutls_005fx509_005fcrq_005fsign">gnutls_x509_crq_sign</a></td><td width="60%">These signing functions will no longer sign using SHA1, but with a secure hash algorithm.</td></tr>
<tr><td width="30%"><a class="ref" href="#gnutls_005fcertificate_005fset_005focsp_005fstatus_005frequest_005ffile">gnutls_certificate_set_ocsp_status_request_file</a></td><td width="60%">This function will return an error if the loaded response doesn&rsquo;t match
any of the present certificates. To revert to previous semantics set the <code class="code">GNUTLS_CERTIFICATE_SKIP_OCSP_RESPONSE_CHECK</code>
flag using <a class="ref" href="#gnutls_005fcertificate_005fset_005fflags">gnutls_certificate_set_flags</a>.</td></tr>
<tr><td width="30%">The callback <a class="ref" href="#gnutls_005fprivkey_005fimport_005fext3">gnutls_privkey_import_ext3</a> is not flexible enough for new signature algorithms such as RSA-PSS</td><td width="60%">It is replaced with <a class="ref" href="#gnutls_005fprivkey_005fimport_005fext4">gnutls_privkey_import_ext4</a></td></tr>
<tr><td width="30%">Re-handshake functionality is not applicable under TLS 1.3.</td><td width="60%">It is replaced by separate key update and re-authentication functionality
which can be accessed directly via <a class="ref" href="#gnutls_005fsession_005fkey_005fupdate">gnutls_session_key_update</a> and <a class="ref" href="#gnutls_005freauth">gnutls_reauth</a>.</td></tr>
<tr><td width="30%">TLS session identifiers are not shared with the server under TLS 1.3.</td><td width="60%">The TLS session identifiers are persistent across resumption only on
server side and can be obtained as before via <a class="ref" href="#gnutls_005fsession_005fget_005fid2">gnutls_session_get_id2</a>.</td></tr>
<tr><td width="30%"><a class="ref" href="#gnutls_005fpkcs11_005fprivkey_005fgenerate3">gnutls_pkcs11_privkey_generate3</a>, <a class="ref" href="#gnutls_005fpkcs11_005fcopy_005fsecret_005fkey">gnutls_pkcs11_copy_secret_key</a>, <a class="ref" href="#gnutls_005fpkcs11_005fcopy_005fx509_005fprivkey2">gnutls_pkcs11_copy_x509_privkey2</a></td><td width="60%">These functions no longer create an exportable key by default; they require the flag <code class="code">GNUTLS_PKCS11_OBJ_FLAG_MARK_NOT_SENSITIVE</code> to do so.</td></tr>
<tr><td width="30%"><a class="ref" href="#gnutls_005fdb_005fset_005fretrieve_005ffunction">gnutls_db_set_retrieve_function</a>, <a class="ref" href="#gnutls_005fdb_005fset_005fstore_005ffunction">gnutls_db_set_store_function</a>, <a class="ref" href="#gnutls_005fdb_005fset_005fremove_005ffunction">gnutls_db_set_remove_function</a></td><td width="60%">These functions are no longer relevant under TLS 1.3; resumption under
TLS 1.3 is done via session tickets, c.f. <a class="ref" href="#gnutls_005fsession_005fticket_005fenable_005fserver">gnutls_session_ticket_enable_server</a>.</td></tr>
<tr><td width="30%"><a class="ref" href="#gnutls_005fsession_005fget_005fdata2">gnutls_session_get_data2</a>, <a class="ref" href="#gnutls_005fsession_005fget_005fdata">gnutls_session_get_data</a></td><td width="60%">These functions may introduce a slight delay under TLS 1.3 for few
milliseconds. Check output of <a class="ref" href="#gnutls_005fsession_005fget_005fflags">gnutls_session_get_flags</a> for GNUTLS_SFLAGS_SESSION_TICKET
before calling this function to avoid delays. To work efficiently under
TLS 1.3 this function requires the application setting
<a class="ref" href="#gnutls_005ftransport_005fset_005fpull_005ftimeout_005ffunction">gnutls_transport_set_pull_timeout_function</a>.</td></tr>
<tr><td width="30%">SRP and RSA-PSK key exchanges are not supported under TLS 1.3</td><td width="60%">SRP and RSA-PSK key exchanges are not supported in TLS 1.3, so when these key exchanges are present in a priority string, TLS 1.3 is disabled.</td></tr>
<tr><td width="30%">Anonymous key exchange is not supported under TLS 1.3</td><td width="60%">There is no anonymous key exchange supported under TLS 1.3, so if an anonymous key exchange method is set in a priority string, and no certificate credentials are set in the client or server, TLS 1.3 will not be negotiated.</td></tr>
<tr><td width="30%">ECDHE-PSK and DHE-PSK keywords have the same meaning under TLS 1.3</td><td width="60%">In the priority strings, both <code class="code">ECDHEPSK</code> and <code class="code">DHEPSK</code> indicate the intent to support an ephemeral key exchange with the pre-shared key.  The parameters of the key exchange are negotiated with the supported groups specified in the priority string.</td></tr>
<tr><td width="30%">Authentication-only ciphersuites are not supported under TLS 1.3</td><td width="60%">Ciphersuites with the <code class="code">NULL</code> cipher (i.e., authentication-only) are not supported in TLS 1.3, so when they are specified in a priority string, TLS 1.3 is disabled.</td></tr>
<tr><td width="30%">Supplemental data is not supported under TLS 1.3</td><td width="60%">The TLS supplemental data handshake message (RFC 4680) is not supported under TLS 1.3, so if the application calls <a class="ref" href="#gnutls_005fsupplemental_005fregister">gnutls_supplemental_register</a> or <a class="ref" href="#gnutls_005fsession_005fsupplemental_005fregister">gnutls_session_supplemental_register</a>, TLS 1.3 is disabled.</td></tr>
<tr><td width="30%">The GNUTLS_X509_NO_WELL_DEFINED_EXPIRATION macro is a no-op</td><td width="60%">The macro was non-functional and because of the nature of the
definition of the no-well-defined date for certificates (a real date),
it will not be fixed or re-introduced.</td></tr>
</tbody>
</table>

<hr>
</div>
<div class="appendix-level-extent" id="Support">
<div class="nav-panel">
<p>
Next: <a href="#Error-codes" accesskey="n" rel="next">Error Codes and Descriptions</a>, Previous: <a href="#Upgrading-from-previous-versions" accesskey="p" rel="prev">Upgrading from previous versions</a>, Up: <a href="#Top" accesskey="u" rel="up">GnuTLS</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h2 class="appendix" id="Support-1"><span>Appendix B Support<a class="copiable-link" href="#Support-1"> &para;</a></span></h2>


<ul class="mini-toc">
<li><a href="#Getting-help" accesskey="1">Getting Help</a></li>
<li><a href="#Commercial-Support" accesskey="2">Commercial Support</a></li>
<li><a href="#Bug-Reports" accesskey="3">Bug Reports</a></li>
<li><a href="#Contributing" accesskey="4">Contributing</a></li>
<li><a href="#Certification" accesskey="5">Certification</a></li>
</ul>
<hr>
<div class="section-level-extent" id="Getting-help">
<div class="nav-panel">
<p>
Next: <a href="#Commercial-Support" accesskey="n" rel="next">Commercial Support</a>, Up: <a href="#Support" accesskey="u" rel="up">Support</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Getting-Help"><span>B.1 Getting Help<a class="copiable-link" href="#Getting-Help"> &para;</a></span></h3>

<p>A mailing list where users may help each other exists, and you can
reach it by sending e-mail to <a class="email" href="mailto:gnutls-help@gnutls.org">gnutls-help@gnutls.org</a>.  Archives
of the mailing list discussions, and an interface to manage
subscriptions, is available through the World Wide Web at
<a class="url" href="https://lists.gnutls.org/pipermail/gnutls-help/">https://lists.gnutls.org/pipermail/gnutls-help/</a>.
</p>
<p>A mailing list for developers are also available, see
<a class="url" href="https://www.gnutls.org/lists.html">https://www.gnutls.org/lists.html</a>.
Bug reports should be sent to <a class="email" href="mailto:bugs@gnutls.org">bugs@gnutls.org</a>, see
<a class="ref" href="#Bug-Reports">Bug Reports</a>.
</p>
<hr>
</div>
<div class="section-level-extent" id="Commercial-Support">
<div class="nav-panel">
<p>
Next: <a href="#Bug-Reports" accesskey="n" rel="next">Bug Reports</a>, Previous: <a href="#Getting-help" accesskey="p" rel="prev">Getting Help</a>, Up: <a href="#Support" accesskey="u" rel="up">Support</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Commercial-Support-1"><span>B.2 Commercial Support<a class="copiable-link" href="#Commercial-Support-1"> &para;</a></span></h3>

<p>Commercial support is available for users of GnuTLS. See
<a class="url" href="https://www.gnutls.org/commercial.html">https://www.gnutls.org/commercial.html</a> for more information.
</p>

<hr>
</div>
<div class="section-level-extent" id="Bug-Reports">
<div class="nav-panel">
<p>
Next: <a href="#Contributing" accesskey="n" rel="next">Contributing</a>, Previous: <a href="#Commercial-Support" accesskey="p" rel="prev">Commercial Support</a>, Up: <a href="#Support" accesskey="u" rel="up">Support</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Bug-Reports-1"><span>B.3 Bug Reports<a class="copiable-link" href="#Bug-Reports-1"> &para;</a></span></h3>
<a class="index-entry-id" id="index-reporting-bugs"></a>

<p>If you think you have found a bug in GnuTLS, please investigate it and
report it.
</p>
<ul class="itemize mark-bullet">
<li>Please make sure that the bug is really in GnuTLS, and
preferably also check that it hasn&rsquo;t already been fixed in the latest
version.

</li><li>You have to send us a test case that makes it possible for us to
reproduce the bug.

</li><li>You also have to explain what is wrong; if you get a crash, or
if the results printed are not good and in that case, in what way.
Make sure that the bug report includes all information you would need
to fix this kind of bug for someone else.

</li></ul>

<p>Please make an effort to produce a self-contained report, with
something definite that can be tested or debugged.  Vague queries or
piecemeal messages are difficult to act on and don&rsquo;t help the
development effort.
</p>
<p>If your bug report is good, we will do our best to help you to get a
corrected version of the software; if the bug report is poor, we won&rsquo;t
do anything about it (apart from asking you to send better bug
reports).
</p>
<p>If you think something in this manual is unclear, or downright
incorrect, or if the language needs to be improved, please also send a
note.
</p>
<p>Send your bug report to:
</p>
<div class="center">&lsquo;<samp class="samp">bugs@gnutls.org</samp>&rsquo;
</div>
<hr>
</div>
<div class="section-level-extent" id="Contributing">
<div class="nav-panel">
<p>
Next: <a href="#Certification" accesskey="n" rel="next">Certification</a>, Previous: <a href="#Bug-Reports" accesskey="p" rel="prev">Bug Reports</a>, Up: <a href="#Support" accesskey="u" rel="up">Support</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Contributing-1"><span>B.4 Contributing<a class="copiable-link" href="#Contributing-1"> &para;</a></span></h3>
<a class="index-entry-id" id="index-contributing"></a>
<a class="index-entry-id" id="index-hacking"></a>

<p>If you want to submit a patch for inclusion &ndash; from solving a typo you
discovered, up to adding support for a new feature &ndash; you should
submit it as a bug report, using the process in <a class="ref" href="#Bug-Reports">Bug Reports</a>.  There are some
things that you can do to increase the chances for it to be included
in the official package.
</p>
<p>Unless your patch is very small (say, under 10 lines) we require that
you assign the copyright of your work to the Free Software Foundation.
This is to protect the freedom of the project.  If you have not
already signed papers, we will send you the necessary information when
you submit your contribution.
</p>
<p>For contributions that doesn&rsquo;t consist of actual programming code, the
only guidelines are common sense.  
For code contributions, a number of style guides will help you:
</p>
<ul class="itemize mark-bullet">
<li>Coding Style.
Follow the Linux kernel coding style<a class="footnote" id="DOCF26" href="#FOOT26"><sup>26</sup></a>.

<p>If you normally code using another coding standard, there is no
problem, but you should run the &lsquo;<samp class="samp">indent-gnutls</samp>&rsquo; script found in
the &lsquo;<samp class="samp">devel</samp>&rsquo; directory to reformat the code before submitting your
work.
</p>
</li><li>Use the unified diff format &lsquo;<samp class="samp">diff -u</samp>&rsquo;.

</li><li>Return errors.
No reason whatsoever should abort the execution of the library.  Even
memory allocation errors, e.g. when malloc return NULL, should work
although result in an error code.

</li><li>Design with thread safety in mind.
Don&rsquo;t use global variables.  Don&rsquo;t even write to per-handle global
variables unless the documented behaviour of the function you write is
to write to the per-handle global variable.

</li><li>Avoid using the C math library.
It causes problems for embedded implementations, and in most
situations it is very easy to avoid using it.

</li><li>Document your functions.
Use comments before each function headers, that, if properly
formatted, are extracted into Texinfo manuals and GTK-DOC web pages.

</li><li>Supply a ChangeLog and NEWS entries, where appropriate.

</li></ul>

<hr>
</div>
<div class="section-level-extent" id="Certification">
<div class="nav-panel">
<p>
Previous: <a href="#Contributing" accesskey="p" rel="prev">Contributing</a>, Up: <a href="#Support" accesskey="u" rel="up">Support</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Certification-1"><span>B.5 Certification<a class="copiable-link" href="#Certification-1"> &para;</a></span></h3>
<a class="index-entry-id" id="index-certification"></a>

<p>There are certifications from national or international bodies which &quot;prove&quot;
to an auditor that the crypto component follows some best practices, such
as unit testing and reliance on well known crypto primitives.
</p>
<p>GnuTLS has support for the FIPS 140-2 certification under Red Hat Enterprise Linux.
See <a class="ref" href="#FIPS140_002d2-mode">FIPS140-2 mode</a> for more information.
</p>
<hr>
</div>
</div>
<div class="appendix-level-extent" id="Error-codes">
<div class="nav-panel">
<p>
Next: <a href="#Supported-ciphersuites" accesskey="n" rel="next">Supported Ciphersuites</a>, Previous: <a href="#Support" accesskey="p" rel="prev">Support</a>, Up: <a href="#Top" accesskey="u" rel="up">GnuTLS</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h2 class="appendix" id="Error-Codes-and-Descriptions"><span>Appendix C Error Codes and Descriptions<a class="copiable-link" href="#Error-Codes-and-Descriptions"> &para;</a></span></h2>
<a class="index-entry-id" id="index-error-codes"></a>

<p>The error codes used throughout the library are described below.  The
return code <code class="code">GNUTLS_E_SUCCESS</code> indicates a successful operation, and
is guaranteed to have the value 0, so you can use it in logical
expressions.
</p>
<table class="multitable">
<tbody><tr><td width="15%">0</td><td width="40%">GNUTLS_E_SUCCESS</td><td width="37%">Success.</td></tr>
<tr><td width="15%">-3</td><td width="40%">GNUTLS_E_UNKNOWN_COMPRESSION_ALGORITHM</td><td width="37%">Could not negotiate a supported compression method.</td></tr>
<tr><td width="15%">-6</td><td width="40%">GNUTLS_E_UNKNOWN_CIPHER_TYPE</td><td width="37%">The cipher type is unsupported.</td></tr>
<tr><td width="15%">-7</td><td width="40%">GNUTLS_E_LARGE_PACKET</td><td width="37%">The transmitted packet is too large (EMSGSIZE).</td></tr>
<tr><td width="15%">-8</td><td width="40%">GNUTLS_E_UNSUPPORTED_VERSION_PACKET</td><td width="37%">A packet with illegal or unsupported version was received.</td></tr>
<tr><td width="15%">-9</td><td width="40%">GNUTLS_E_UNEXPECTED_PACKET_LENGTH</td><td width="37%">Error decoding the received TLS packet.</td></tr>
<tr><td width="15%">-10</td><td width="40%">GNUTLS_E_INVALID_SESSION</td><td width="37%">The specified session has been invalidated for some reason.</td></tr>
<tr><td width="15%">-12</td><td width="40%">GNUTLS_E_FATAL_ALERT_RECEIVED</td><td width="37%">A TLS fatal alert has been received.</td></tr>
<tr><td width="15%">-15</td><td width="40%">GNUTLS_E_UNEXPECTED_PACKET</td><td width="37%">An unexpected TLS packet was received.</td></tr>
<tr><td width="15%">-16</td><td width="40%">GNUTLS_E_WARNING_ALERT_RECEIVED</td><td width="37%">A TLS warning alert has been received.</td></tr>
<tr><td width="15%">-18</td><td width="40%">GNUTLS_E_ERROR_IN_FINISHED_PACKET</td><td width="37%">An error was encountered at the TLS Finished packet calculation.</td></tr>
<tr><td width="15%">-19</td><td width="40%">GNUTLS_E_UNEXPECTED_HANDSHAKE_PACKET</td><td width="37%">An unexpected TLS handshake packet was received.</td></tr>
<tr><td width="15%">-21</td><td width="40%">GNUTLS_E_UNKNOWN_CIPHER_SUITE</td><td width="37%">Could not negotiate a supported cipher suite.</td></tr>
<tr><td width="15%">-22</td><td width="40%">GNUTLS_E_UNWANTED_ALGORITHM</td><td width="37%">An algorithm that is not enabled was negotiated.</td></tr>
<tr><td width="15%">-23</td><td width="40%">GNUTLS_E_MPI_SCAN_FAILED</td><td width="37%">The scanning of a large integer has failed.</td></tr>
<tr><td width="15%">-24</td><td width="40%">GNUTLS_E_DECRYPTION_FAILED</td><td width="37%">Decryption has failed.</td></tr>
<tr><td width="15%">-25</td><td width="40%">GNUTLS_E_MEMORY_ERROR</td><td width="37%">Internal error in memory allocation.</td></tr>
<tr><td width="15%">-26</td><td width="40%">GNUTLS_E_DECOMPRESSION_FAILED</td><td width="37%">Decompression of the TLS record packet has failed.</td></tr>
<tr><td width="15%">-27</td><td width="40%">GNUTLS_E_COMPRESSION_FAILED</td><td width="37%">Compression of the TLS record packet has failed.</td></tr>
<tr><td width="15%">-28</td><td width="40%">GNUTLS_E_AGAIN</td><td width="37%">Resource temporarily unavailable, try again.</td></tr>
<tr><td width="15%">-29</td><td width="40%">GNUTLS_E_EXPIRED</td><td width="37%">The session or certificate has expired.</td></tr>
<tr><td width="15%">-30</td><td width="40%">GNUTLS_E_DB_ERROR</td><td width="37%">Error in Database backend.</td></tr>
<tr><td width="15%">-31</td><td width="40%">GNUTLS_E_SRP_PWD_ERROR</td><td width="37%">Error in password/key file.</td></tr>
<tr><td width="15%">-32</td><td width="40%">GNUTLS_E_INSUFFICIENT_CREDENTIALS</td><td width="37%">Insufficient credentials for that request.</td></tr>
<tr><td width="15%">-33</td><td width="40%">GNUTLS_E_HASH_FAILED</td><td width="37%">Hashing has failed.</td></tr>
<tr><td width="15%">-34</td><td width="40%">GNUTLS_E_BASE64_DECODING_ERROR</td><td width="37%">Base64 decoding error.</td></tr>
<tr><td width="15%">-35</td><td width="40%">GNUTLS_E_MPI_PRINT_FAILED</td><td width="37%">Could not export a large integer.</td></tr>
<tr><td width="15%">-37</td><td width="40%">GNUTLS_E_REHANDSHAKE</td><td width="37%">Rehandshake was requested by the peer.</td></tr>
<tr><td width="15%">-38</td><td width="40%">GNUTLS_E_GOT_APPLICATION_DATA</td><td width="37%">TLS Application data were received, while expecting handshake data.</td></tr>
<tr><td width="15%">-39</td><td width="40%">GNUTLS_E_RECORD_LIMIT_REACHED</td><td width="37%">The upper limit of record packet sequence numbers has been reached. Wow!</td></tr>
<tr><td width="15%">-40</td><td width="40%">GNUTLS_E_ENCRYPTION_FAILED</td><td width="37%">Encryption has failed.</td></tr>
<tr><td width="15%">-43</td><td width="40%">GNUTLS_E_CERTIFICATE_ERROR</td><td width="37%">Error in the certificate.</td></tr>
<tr><td width="15%">-44</td><td width="40%">GNUTLS_E_PK_ENCRYPTION_FAILED</td><td width="37%">Public key encryption has failed.</td></tr>
<tr><td width="15%">-45</td><td width="40%">GNUTLS_E_PK_DECRYPTION_FAILED</td><td width="37%">Public key decryption has failed.</td></tr>
<tr><td width="15%">-46</td><td width="40%">GNUTLS_E_PK_SIGN_FAILED</td><td width="37%">Public key signing has failed.</td></tr>
<tr><td width="15%">-47</td><td width="40%">GNUTLS_E_X509_UNSUPPORTED_CRITICAL_EXTENSION</td><td width="37%">Unsupported critical extension in X.509 certificate.</td></tr>
<tr><td width="15%">-48</td><td width="40%">GNUTLS_E_KEY_USAGE_VIOLATION</td><td width="37%">Key usage violation in certificate has been detected.</td></tr>
<tr><td width="15%">-49</td><td width="40%">GNUTLS_E_NO_CERTIFICATE_FOUND</td><td width="37%">No certificate was found.</td></tr>
<tr><td width="15%">-50</td><td width="40%">GNUTLS_E_INVALID_REQUEST</td><td width="37%">The request is invalid.</td></tr>
<tr><td width="15%">-51</td><td width="40%">GNUTLS_E_SHORT_MEMORY_BUFFER</td><td width="37%">The given memory buffer is too short to hold parameters.</td></tr>
<tr><td width="15%">-52</td><td width="40%">GNUTLS_E_INTERRUPTED</td><td width="37%">Function was interrupted.</td></tr>
<tr><td width="15%">-53</td><td width="40%">GNUTLS_E_PUSH_ERROR</td><td width="37%">Error in the push function.</td></tr>
<tr><td width="15%">-54</td><td width="40%">GNUTLS_E_PULL_ERROR</td><td width="37%">Error in the pull function.</td></tr>
<tr><td width="15%">-55</td><td width="40%">GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER</td><td width="37%">An illegal parameter has been received.</td></tr>
<tr><td width="15%">-56</td><td width="40%">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</td><td width="37%">The requested data were not available.</td></tr>
<tr><td width="15%">-57</td><td width="40%">GNUTLS_E_PKCS1_WRONG_PAD</td><td width="37%">Wrong padding in PKCS1 packet.</td></tr>
<tr><td width="15%">-58</td><td width="40%">GNUTLS_E_RECEIVED_ILLEGAL_EXTENSION</td><td width="37%">An illegal TLS extension was received.</td></tr>
<tr><td width="15%">-59</td><td width="40%">GNUTLS_E_INTERNAL_ERROR</td><td width="37%">GnuTLS internal error.</td></tr>
<tr><td width="15%">-60</td><td width="40%">GNUTLS_E_CERTIFICATE_KEY_MISMATCH</td><td width="37%">The certificate and the given key do not match.</td></tr>
<tr><td width="15%">-61</td><td width="40%">GNUTLS_E_UNSUPPORTED_CERTIFICATE_TYPE</td><td width="37%">The certificate type is not supported.</td></tr>
<tr><td width="15%">-62</td><td width="40%">GNUTLS_E_X509_UNKNOWN_SAN</td><td width="37%">Unknown Subject Alternative name in X.509 certificate.</td></tr>
<tr><td width="15%">-63</td><td width="40%">GNUTLS_E_DH_PRIME_UNACCEPTABLE</td><td width="37%">The Diffie-Hellman prime sent by the server is not acceptable (not long enough).</td></tr>
<tr><td width="15%">-64</td><td width="40%">GNUTLS_E_FILE_ERROR</td><td width="37%">Error while reading file.</td></tr>
<tr><td width="15%">-67</td><td width="40%">GNUTLS_E_ASN1_ELEMENT_NOT_FOUND</td><td width="37%">ASN1 parser: Element was not found.</td></tr>
<tr><td width="15%">-68</td><td width="40%">GNUTLS_E_ASN1_IDENTIFIER_NOT_FOUND</td><td width="37%">ASN1 parser: Identifier was not found</td></tr>
<tr><td width="15%">-69</td><td width="40%">GNUTLS_E_ASN1_DER_ERROR</td><td width="37%">ASN1 parser: Error in DER parsing.</td></tr>
<tr><td width="15%">-70</td><td width="40%">GNUTLS_E_ASN1_VALUE_NOT_FOUND</td><td width="37%">ASN1 parser: Value was not found.</td></tr>
<tr><td width="15%">-71</td><td width="40%">GNUTLS_E_ASN1_GENERIC_ERROR</td><td width="37%">ASN1 parser: Generic parsing error.</td></tr>
<tr><td width="15%">-72</td><td width="40%">GNUTLS_E_ASN1_VALUE_NOT_VALID</td><td width="37%">ASN1 parser: Value is not valid.</td></tr>
<tr><td width="15%">-73</td><td width="40%">GNUTLS_E_ASN1_TAG_ERROR</td><td width="37%">ASN1 parser: Error in TAG.</td></tr>
<tr><td width="15%">-74</td><td width="40%">GNUTLS_E_ASN1_TAG_IMPLICIT</td><td width="37%">ASN1 parser: error in implicit tag</td></tr>
<tr><td width="15%">-75</td><td width="40%">GNUTLS_E_ASN1_TYPE_ANY_ERROR</td><td width="37%">ASN1 parser: Error in type &rsquo;ANY&rsquo;.</td></tr>
<tr><td width="15%">-76</td><td width="40%">GNUTLS_E_ASN1_SYNTAX_ERROR</td><td width="37%">ASN1 parser: Syntax error.</td></tr>
<tr><td width="15%">-77</td><td width="40%">GNUTLS_E_ASN1_DER_OVERFLOW</td><td width="37%">ASN1 parser: Overflow in DER parsing.</td></tr>
<tr><td width="15%">-78</td><td width="40%">GNUTLS_E_TOO_MANY_EMPTY_PACKETS</td><td width="37%">Too many empty record packets have been received.</td></tr>
<tr><td width="15%">-79</td><td width="40%">GNUTLS_E_OPENPGP_UID_REVOKED</td><td width="37%">The OpenPGP User ID is revoked.</td></tr>
<tr><td width="15%">-80</td><td width="40%">GNUTLS_E_UNKNOWN_PK_ALGORITHM</td><td width="37%">An unknown public key algorithm was encountered.</td></tr>
<tr><td width="15%">-81</td><td width="40%">GNUTLS_E_TOO_MANY_HANDSHAKE_PACKETS</td><td width="37%">Too many handshake packets have been received.</td></tr>
<tr><td width="15%">-82</td><td width="40%">GNUTLS_E_RECEIVED_DISALLOWED_NAME</td><td width="37%">A disallowed SNI server name has been received.</td></tr>
<tr><td width="15%">-84</td><td width="40%">GNUTLS_E_NO_TEMPORARY_RSA_PARAMS</td><td width="37%">No temporary RSA parameters were found.</td></tr>
<tr><td width="15%">-86</td><td width="40%">GNUTLS_E_NO_COMPRESSION_ALGORITHMS</td><td width="37%">No supported compression algorithms have been found.</td></tr>
<tr><td width="15%">-87</td><td width="40%">GNUTLS_E_NO_CIPHER_SUITES</td><td width="37%">No supported cipher suites have been found.</td></tr>
<tr><td width="15%">-88</td><td width="40%">GNUTLS_E_OPENPGP_GETKEY_FAILED</td><td width="37%">Could not get OpenPGP key.</td></tr>
<tr><td width="15%">-89</td><td width="40%">GNUTLS_E_PK_SIG_VERIFY_FAILED</td><td width="37%">Public key signature verification has failed.</td></tr>
<tr><td width="15%">-90</td><td width="40%">GNUTLS_E_ILLEGAL_SRP_USERNAME</td><td width="37%">The SRP username supplied is illegal.</td></tr>
<tr><td width="15%">-91</td><td width="40%">GNUTLS_E_SRP_PWD_PARSING_ERROR</td><td width="37%">Parsing error in password/key file.</td></tr>
<tr><td width="15%">-93</td><td width="40%">GNUTLS_E_NO_TEMPORARY_DH_PARAMS</td><td width="37%">No temporary DH parameters were found.</td></tr>
<tr><td width="15%">-94</td><td width="40%">GNUTLS_E_OPENPGP_FINGERPRINT_UNSUPPORTED</td><td width="37%">The OpenPGP fingerprint is not supported.</td></tr>
<tr><td width="15%">-95</td><td width="40%">GNUTLS_E_X509_UNSUPPORTED_ATTRIBUTE</td><td width="37%">The certificate has unsupported attributes.</td></tr>
<tr><td width="15%">-96</td><td width="40%">GNUTLS_E_UNKNOWN_HASH_ALGORITHM</td><td width="37%">The hash algorithm is unknown.</td></tr>
<tr><td width="15%">-97</td><td width="40%">GNUTLS_E_UNKNOWN_PKCS_CONTENT_TYPE</td><td width="37%">The PKCS structure&rsquo;s content type is unknown.</td></tr>
<tr><td width="15%">-98</td><td width="40%">GNUTLS_E_UNKNOWN_PKCS_BAG_TYPE</td><td width="37%">The PKCS structure&rsquo;s bag type is unknown.</td></tr>
<tr><td width="15%">-99</td><td width="40%">GNUTLS_E_INVALID_PASSWORD</td><td width="37%">The given password contains invalid characters.</td></tr>
<tr><td width="15%">-100</td><td width="40%">GNUTLS_E_MAC_VERIFY_FAILED</td><td width="37%">The Message Authentication Code verification failed.</td></tr>
<tr><td width="15%">-101</td><td width="40%">GNUTLS_E_CONSTRAINT_ERROR</td><td width="37%">Some constraint limits were reached.</td></tr>
<tr><td width="15%">-104</td><td width="40%">GNUTLS_E_IA_VERIFY_FAILED</td><td width="37%">Verifying TLS/IA phase checksum failed</td></tr>
<tr><td width="15%">-105</td><td width="40%">GNUTLS_E_UNKNOWN_ALGORITHM</td><td width="37%">The specified algorithm or protocol is unknown.</td></tr>
<tr><td width="15%">-106</td><td width="40%">GNUTLS_E_UNSUPPORTED_SIGNATURE_ALGORITHM</td><td width="37%">The signature algorithm is not supported.</td></tr>
<tr><td width="15%">-107</td><td width="40%">GNUTLS_E_SAFE_RENEGOTIATION_FAILED</td><td width="37%">Safe renegotiation failed.</td></tr>
<tr><td width="15%">-108</td><td width="40%">GNUTLS_E_UNSAFE_RENEGOTIATION_DENIED</td><td width="37%">Unsafe renegotiation denied.</td></tr>
<tr><td width="15%">-109</td><td width="40%">GNUTLS_E_UNKNOWN_SRP_USERNAME</td><td width="37%">The username supplied is unknown.</td></tr>
<tr><td width="15%">-110</td><td width="40%">GNUTLS_E_PREMATURE_TERMINATION</td><td width="37%">The TLS connection was non-properly terminated.</td></tr>
<tr><td width="15%">-111</td><td width="40%">GNUTLS_E_MALFORMED_CIDR</td><td width="37%">CIDR name constraint is malformed in size or structure.</td></tr>
<tr><td width="15%">-112</td><td width="40%">GNUTLS_E_CERTIFICATE_REQUIRED</td><td width="37%">Certificate is required.</td></tr>
<tr><td width="15%">-113</td><td width="40%">GNUTLS_E_UNSUPPORTED_ENCRYPTION_ALGORITHM</td><td width="37%">The encryption algorithm is not supported.</td></tr>
<tr><td width="15%">-201</td><td width="40%">GNUTLS_E_BASE64_ENCODING_ERROR</td><td width="37%">Base64 encoding error.</td></tr>
<tr><td width="15%">-202</td><td width="40%">GNUTLS_E_INCOMPATIBLE_GCRYPT_LIBRARY</td><td width="37%">The crypto library version is too old.</td></tr>
<tr><td width="15%">-203</td><td width="40%">GNUTLS_E_INCOMPATIBLE_LIBTASN1_LIBRARY</td><td width="37%">The tasn1 library version is too old.</td></tr>
<tr><td width="15%">-204</td><td width="40%">GNUTLS_E_OPENPGP_KEYRING_ERROR</td><td width="37%">Error loading the keyring.</td></tr>
<tr><td width="15%">-205</td><td width="40%">GNUTLS_E_X509_UNSUPPORTED_OID</td><td width="37%">The OID is not supported.</td></tr>
<tr><td width="15%">-206</td><td width="40%">GNUTLS_E_RANDOM_FAILED</td><td width="37%">Failed to acquire random data.</td></tr>
<tr><td width="15%">-207</td><td width="40%">GNUTLS_E_BASE64_UNEXPECTED_HEADER_ERROR</td><td width="37%">Base64 unexpected header error.</td></tr>
<tr><td width="15%">-208</td><td width="40%">GNUTLS_E_OPENPGP_SUBKEY_ERROR</td><td width="37%">Could not find OpenPGP subkey.</td></tr>
<tr><td width="15%">-209</td><td width="40%">GNUTLS_E_CRYPTO_ALREADY_REGISTERED</td><td width="37%">There is already a crypto algorithm with lower priority.</td></tr>
<tr><td width="15%">-210</td><td width="40%">GNUTLS_E_HANDSHAKE_TOO_LARGE</td><td width="37%">The handshake data size is too large.</td></tr>
<tr><td width="15%">-211</td><td width="40%">GNUTLS_E_CRYPTODEV_IOCTL_ERROR</td><td width="37%">Error interfacing with /dev/crypto</td></tr>
<tr><td width="15%">-212</td><td width="40%">GNUTLS_E_CRYPTODEV_DEVICE_ERROR</td><td width="37%">Error opening /dev/crypto</td></tr>
<tr><td width="15%">-213</td><td width="40%">GNUTLS_E_CHANNEL_BINDING_NOT_AVAILABLE</td><td width="37%">Channel binding data not available</td></tr>
<tr><td width="15%">-214</td><td width="40%">GNUTLS_E_BAD_COOKIE</td><td width="37%">The cookie was bad.</td></tr>
<tr><td width="15%">-215</td><td width="40%">GNUTLS_E_OPENPGP_PREFERRED_KEY_ERROR</td><td width="37%">The OpenPGP key has not a preferred key set.</td></tr>
<tr><td width="15%">-216</td><td width="40%">GNUTLS_E_INCOMPAT_DSA_KEY_WITH_TLS_PROTOCOL</td><td width="37%">The given DSA key is incompatible with the selected TLS protocol.</td></tr>
<tr><td width="15%">-217</td><td width="40%">GNUTLS_E_INSUFFICIENT_SECURITY</td><td width="37%">One of the involved algorithms has insufficient security level.</td></tr>
<tr><td width="15%">-292</td><td width="40%">GNUTLS_E_HEARTBEAT_PONG_RECEIVED</td><td width="37%">A heartbeat pong message was received.</td></tr>
<tr><td width="15%">-293</td><td width="40%">GNUTLS_E_HEARTBEAT_PING_RECEIVED</td><td width="37%">A heartbeat ping message was received.</td></tr>
<tr><td width="15%">-294</td><td width="40%">GNUTLS_E_UNRECOGNIZED_NAME</td><td width="37%">The SNI host name not recognised.</td></tr>
<tr><td width="15%">-300</td><td width="40%">GNUTLS_E_PKCS11_ERROR</td><td width="37%">PKCS #11 error.</td></tr>
<tr><td width="15%">-301</td><td width="40%">GNUTLS_E_PKCS11_LOAD_ERROR</td><td width="37%">PKCS #11 initialization error.</td></tr>
<tr><td width="15%">-302</td><td width="40%">GNUTLS_E_PARSING_ERROR</td><td width="37%">Error in parsing.</td></tr>
<tr><td width="15%">-303</td><td width="40%">GNUTLS_E_PKCS11_PIN_ERROR</td><td width="37%">Error in provided PIN.</td></tr>
<tr><td width="15%">-305</td><td width="40%">GNUTLS_E_PKCS11_SLOT_ERROR</td><td width="37%">PKCS #11 error in slot</td></tr>
<tr><td width="15%">-306</td><td width="40%">GNUTLS_E_LOCKING_ERROR</td><td width="37%">Thread locking error</td></tr>
<tr><td width="15%">-307</td><td width="40%">GNUTLS_E_PKCS11_ATTRIBUTE_ERROR</td><td width="37%">PKCS #11 error in attribute</td></tr>
<tr><td width="15%">-308</td><td width="40%">GNUTLS_E_PKCS11_DEVICE_ERROR</td><td width="37%">PKCS #11 error in device</td></tr>
<tr><td width="15%">-309</td><td width="40%">GNUTLS_E_PKCS11_DATA_ERROR</td><td width="37%">PKCS #11 error in data</td></tr>
<tr><td width="15%">-310</td><td width="40%">GNUTLS_E_PKCS11_UNSUPPORTED_FEATURE_ERROR</td><td width="37%">PKCS #11 unsupported feature</td></tr>
<tr><td width="15%">-311</td><td width="40%">GNUTLS_E_PKCS11_KEY_ERROR</td><td width="37%">PKCS #11 error in key</td></tr>
<tr><td width="15%">-312</td><td width="40%">GNUTLS_E_PKCS11_PIN_EXPIRED</td><td width="37%">PKCS #11 PIN expired</td></tr>
<tr><td width="15%">-313</td><td width="40%">GNUTLS_E_PKCS11_PIN_LOCKED</td><td width="37%">PKCS #11 PIN locked</td></tr>
<tr><td width="15%">-314</td><td width="40%">GNUTLS_E_PKCS11_SESSION_ERROR</td><td width="37%">PKCS #11 error in session</td></tr>
<tr><td width="15%">-315</td><td width="40%">GNUTLS_E_PKCS11_SIGNATURE_ERROR</td><td width="37%">PKCS #11 error in signature</td></tr>
<tr><td width="15%">-316</td><td width="40%">GNUTLS_E_PKCS11_TOKEN_ERROR</td><td width="37%">PKCS #11 error in token</td></tr>
<tr><td width="15%">-317</td><td width="40%">GNUTLS_E_PKCS11_USER_ERROR</td><td width="37%">PKCS #11 user error</td></tr>
<tr><td width="15%">-318</td><td width="40%">GNUTLS_E_CRYPTO_INIT_FAILED</td><td width="37%">The initialization of crypto backend has failed.</td></tr>
<tr><td width="15%">-319</td><td width="40%">GNUTLS_E_TIMEDOUT</td><td width="37%">The operation timed out</td></tr>
<tr><td width="15%">-320</td><td width="40%">GNUTLS_E_USER_ERROR</td><td width="37%">The operation was cancelled due to user error</td></tr>
<tr><td width="15%">-321</td><td width="40%">GNUTLS_E_ECC_NO_SUPPORTED_CURVES</td><td width="37%">No supported ECC curves were found</td></tr>
<tr><td width="15%">-322</td><td width="40%">GNUTLS_E_ECC_UNSUPPORTED_CURVE</td><td width="37%">The curve is unsupported</td></tr>
<tr><td width="15%">-323</td><td width="40%">GNUTLS_E_PKCS11_REQUESTED_OBJECT_NOT_AVAILBLE</td><td width="37%">The requested PKCS #11 object is not available</td></tr>
<tr><td width="15%">-324</td><td width="40%">GNUTLS_E_CERTIFICATE_LIST_UNSORTED</td><td width="37%">The provided X.509 certificate list is not sorted (in subject to issuer order)</td></tr>
<tr><td width="15%">-325</td><td width="40%">GNUTLS_E_ILLEGAL_PARAMETER</td><td width="37%">An illegal parameter was found.</td></tr>
<tr><td width="15%">-326</td><td width="40%">GNUTLS_E_NO_PRIORITIES_WERE_SET</td><td width="37%">No or insufficient priorities were set.</td></tr>
<tr><td width="15%">-327</td><td width="40%">GNUTLS_E_X509_UNSUPPORTED_EXTENSION</td><td width="37%">Unsupported extension in X.509 certificate.</td></tr>
<tr><td width="15%">-328</td><td width="40%">GNUTLS_E_SESSION_EOF</td><td width="37%">Peer has terminated the connection</td></tr>
<tr><td width="15%">-329</td><td width="40%">GNUTLS_E_TPM_ERROR</td><td width="37%">TPM error.</td></tr>
<tr><td width="15%">-330</td><td width="40%">GNUTLS_E_TPM_KEY_PASSWORD_ERROR</td><td width="37%">Error in provided password for key to be loaded in TPM.</td></tr>
<tr><td width="15%">-331</td><td width="40%">GNUTLS_E_TPM_SRK_PASSWORD_ERROR</td><td width="37%">Error in provided SRK password for TPM.</td></tr>
<tr><td width="15%">-332</td><td width="40%">GNUTLS_E_TPM_SESSION_ERROR</td><td width="37%">Cannot initialize a session with the TPM.</td></tr>
<tr><td width="15%">-333</td><td width="40%">GNUTLS_E_TPM_KEY_NOT_FOUND</td><td width="37%">TPM key was not found in persistent storage.</td></tr>
<tr><td width="15%">-334</td><td width="40%">GNUTLS_E_TPM_UNINITIALIZED</td><td width="37%">TPM is not initialized.</td></tr>
<tr><td width="15%">-335</td><td width="40%">GNUTLS_E_TPM_NO_LIB</td><td width="37%">The TPM library (trousers) cannot be found.</td></tr>
<tr><td width="15%">-340</td><td width="40%">GNUTLS_E_NO_CERTIFICATE_STATUS</td><td width="37%">There is no certificate status (OCSP).</td></tr>
<tr><td width="15%">-341</td><td width="40%">GNUTLS_E_OCSP_RESPONSE_ERROR</td><td width="37%">The OCSP response is invalid</td></tr>
<tr><td width="15%">-342</td><td width="40%">GNUTLS_E_RANDOM_DEVICE_ERROR</td><td width="37%">Error in the system&rsquo;s randomness device.</td></tr>
<tr><td width="15%">-343</td><td width="40%">GNUTLS_E_AUTH_ERROR</td><td width="37%">Could not authenticate peer.</td></tr>
<tr><td width="15%">-344</td><td width="40%">GNUTLS_E_NO_APPLICATION_PROTOCOL</td><td width="37%">No common application protocol could be negotiated.</td></tr>
<tr><td width="15%">-345</td><td width="40%">GNUTLS_E_SOCKETS_INIT_ERROR</td><td width="37%">Error in sockets initialization.</td></tr>
<tr><td width="15%">-346</td><td width="40%">GNUTLS_E_KEY_IMPORT_FAILED</td><td width="37%">Failed to import the key into store.</td></tr>
<tr><td width="15%">-347</td><td width="40%">GNUTLS_E_INAPPROPRIATE_FALLBACK</td><td width="37%">A connection with inappropriate fallback was attempted.</td></tr>
<tr><td width="15%">-348</td><td width="40%">GNUTLS_E_CERTIFICATE_VERIFICATION_ERROR</td><td width="37%">Error in the certificate verification.</td></tr>
<tr><td width="15%">-349</td><td width="40%">GNUTLS_E_PRIVKEY_VERIFICATION_ERROR</td><td width="37%">Error in the private key verification; seed doesn&rsquo;t match.</td></tr>
<tr><td width="15%">-350</td><td width="40%">GNUTLS_E_UNEXPECTED_EXTENSIONS_LENGTH</td><td width="37%">Invalid TLS extensions length field.</td></tr>
<tr><td width="15%">-351</td><td width="40%">GNUTLS_E_ASN1_EMBEDDED_NULL_IN_STRING</td><td width="37%">The provided string has an embedded null.</td></tr>
<tr><td width="15%">-400</td><td width="40%">GNUTLS_E_SELF_TEST_ERROR</td><td width="37%">Error while performing self checks.</td></tr>
<tr><td width="15%">-401</td><td width="40%">GNUTLS_E_NO_SELF_TEST</td><td width="37%">There is no self test for this algorithm.</td></tr>
<tr><td width="15%">-402</td><td width="40%">GNUTLS_E_LIB_IN_ERROR_STATE</td><td width="37%">An error has been detected in the library and cannot continue operations.</td></tr>
<tr><td width="15%">-403</td><td width="40%">GNUTLS_E_PK_GENERATION_ERROR</td><td width="37%">Error in public key generation.</td></tr>
<tr><td width="15%">-404</td><td width="40%">GNUTLS_E_IDNA_ERROR</td><td width="37%">There was an issue converting to or from UTF8.</td></tr>
<tr><td width="15%">-406</td><td width="40%">GNUTLS_E_SESSION_USER_ID_CHANGED</td><td width="37%">Peer&rsquo;s certificate or username has changed during a rehandshake.</td></tr>
<tr><td width="15%">-407</td><td width="40%">GNUTLS_E_HANDSHAKE_DURING_FALSE_START</td><td width="37%">Attempted handshake during false start.</td></tr>
<tr><td width="15%">-408</td><td width="40%">GNUTLS_E_UNAVAILABLE_DURING_HANDSHAKE</td><td width="37%">Cannot perform this action while handshake is in progress.</td></tr>
<tr><td width="15%">-409</td><td width="40%">GNUTLS_E_PK_INVALID_PUBKEY</td><td width="37%">The public key is invalid.</td></tr>
<tr><td width="15%">-410</td><td width="40%">GNUTLS_E_PK_INVALID_PRIVKEY</td><td width="37%">The private key is invalid.</td></tr>
<tr><td width="15%">-411</td><td width="40%">GNUTLS_E_NOT_YET_ACTIVATED</td><td width="37%">The certificate is not yet activated.</td></tr>
<tr><td width="15%">-412</td><td width="40%">GNUTLS_E_INVALID_UTF8_STRING</td><td width="37%">The given string contains invalid UTF-8 characters.</td></tr>
<tr><td width="15%">-413</td><td width="40%">GNUTLS_E_NO_EMBEDDED_DATA</td><td width="37%">There are no embedded data in the structure.</td></tr>
<tr><td width="15%">-414</td><td width="40%">GNUTLS_E_INVALID_UTF8_EMAIL</td><td width="37%">The given email string contains non-ASCII characters before &rsquo;.&#769;</td></tr>
<tr><td width="15%">-415</td><td width="40%">GNUTLS_E_INVALID_PASSWORD_STRING</td><td width="37%">The given password contains invalid characters.</td></tr>
<tr><td width="15%">-416</td><td width="40%">GNUTLS_E_CERTIFICATE_TIME_ERROR</td><td width="37%">Error in the time fields of certificate.</td></tr>
<tr><td width="15%">-417</td><td width="40%">GNUTLS_E_RECORD_OVERFLOW</td><td width="37%">A TLS record packet with invalid length was received.</td></tr>
<tr><td width="15%">-418</td><td width="40%">GNUTLS_E_ASN1_TIME_ERROR</td><td width="37%">The DER time encoding is invalid.</td></tr>
<tr><td width="15%">-419</td><td width="40%">GNUTLS_E_INCOMPATIBLE_SIG_WITH_KEY</td><td width="37%">The signature is incompatible with the public key.</td></tr>
<tr><td width="15%">-420</td><td width="40%">GNUTLS_E_PK_INVALID_PUBKEY_PARAMS</td><td width="37%">The public key parameters are invalid.</td></tr>
<tr><td width="15%">-421</td><td width="40%">GNUTLS_E_PK_NO_VALIDATION_PARAMS</td><td width="37%">There are no validation parameters present.</td></tr>
<tr><td width="15%">-422</td><td width="40%">GNUTLS_E_OCSP_MISMATCH_WITH_CERTS</td><td width="37%">The OCSP response provided doesn&rsquo;t match the available certificates</td></tr>
<tr><td width="15%">-423</td><td width="40%">GNUTLS_E_NO_COMMON_KEY_SHARE</td><td width="37%">No common key share with peer.</td></tr>
<tr><td width="15%">-424</td><td width="40%">GNUTLS_E_REAUTH_REQUEST</td><td width="37%">Re-authentication was requested by the peer.</td></tr>
<tr><td width="15%">-425</td><td width="40%">GNUTLS_E_TOO_MANY_MATCHES</td><td width="37%">More than a single object matches the criteria.</td></tr>
<tr><td width="15%">-426</td><td width="40%">GNUTLS_E_CRL_VERIFICATION_ERROR</td><td width="37%">Error in the CRL verification.</td></tr>
<tr><td width="15%">-427</td><td width="40%">GNUTLS_E_MISSING_EXTENSION</td><td width="37%">An required TLS extension was received.</td></tr>
<tr><td width="15%">-428</td><td width="40%">GNUTLS_E_DB_ENTRY_EXISTS</td><td width="37%">The Database entry already exists.</td></tr>
<tr><td width="15%">-429</td><td width="40%">GNUTLS_E_EARLY_DATA_REJECTED</td><td width="37%">The early data were rejected.</td></tr>
<tr><td width="15%">-430</td><td width="40%">GNUTLS_E_X509_DUPLICATE_EXTENSION</td><td width="37%">Duplicate extension in X.509 certificate.</td></tr>
</tbody>
</table>


<hr>
</div>
<div class="appendix-level-extent" id="Supported-ciphersuites">
<div class="nav-panel">
<p>
Next: <a href="#API-reference" accesskey="n" rel="next">API reference</a>, Previous: <a href="#Error-codes" accesskey="p" rel="prev">Error Codes and Descriptions</a>, Up: <a href="#Top" accesskey="u" rel="up">GnuTLS</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h2 class="appendix" id="Supported-Ciphersuites"><span>Appendix D Supported Ciphersuites<a class="copiable-link" href="#Supported-Ciphersuites"> &para;</a></span></h2>
<a class="anchor" id="ciphersuites"></a><a class="index-entry-id" id="index-ciphersuites"></a>

<h3 class="heading" id="Ciphersuites"><span>Ciphersuites<a class="copiable-link" href="#Ciphersuites"> &para;</a></span></h3>
<table class="multitable">
<thead><tr><th width="60%">Ciphersuite name</th><th width="20%">TLS ID</th><th width="20%">Since</th></tr></thead>
<tbody><tr><td width="60%">TLS_AES_128_GCM_SHA256</td><td width="20%">0x13 0x01</td><td width="20%">TLS1.3</td></tr>
<tr><td width="60%">TLS_AES_256_GCM_SHA384</td><td width="20%">0x13 0x02</td><td width="20%">TLS1.3</td></tr>
<tr><td width="60%">TLS_CHACHA20_POLY1305_SHA256</td><td width="20%">0x13 0x03</td><td width="20%">TLS1.3</td></tr>
<tr><td width="60%">TLS_AES_128_CCM_SHA256</td><td width="20%">0x13 0x04</td><td width="20%">TLS1.3</td></tr>
<tr><td width="60%">TLS_AES_128_CCM_8_SHA256</td><td width="20%">0x13 0x05</td><td width="20%">TLS1.3</td></tr>
<tr><td width="60%">TLS_RSA_NULL_MD5</td><td width="20%">0x00 0x01</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_RSA_NULL_SHA1</td><td width="20%">0x00 0x02</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_RSA_NULL_SHA256</td><td width="20%">0x00 0x3B</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_RSA_ARCFOUR_128_SHA1</td><td width="20%">0x00 0x05</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_RSA_ARCFOUR_128_MD5</td><td width="20%">0x00 0x04</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_RSA_3DES_EDE_CBC_SHA1</td><td width="20%">0x00 0x0A</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_RSA_AES_128_CBC_SHA1</td><td width="20%">0x00 0x2F</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_RSA_AES_256_CBC_SHA1</td><td width="20%">0x00 0x35</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_RSA_CAMELLIA_128_CBC_SHA256</td><td width="20%">0x00 0xBA</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_RSA_CAMELLIA_256_CBC_SHA256</td><td width="20%">0x00 0xC0</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_RSA_CAMELLIA_128_CBC_SHA1</td><td width="20%">0x00 0x41</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_RSA_CAMELLIA_256_CBC_SHA1</td><td width="20%">0x00 0x84</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_RSA_AES_128_CBC_SHA256</td><td width="20%">0x00 0x3C</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_RSA_AES_256_CBC_SHA256</td><td width="20%">0x00 0x3D</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_RSA_AES_128_GCM_SHA256</td><td width="20%">0x00 0x9C</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_RSA_AES_256_GCM_SHA384</td><td width="20%">0x00 0x9D</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_RSA_CAMELLIA_128_GCM_SHA256</td><td width="20%">0xC0 0x7A</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_RSA_CAMELLIA_256_GCM_SHA384</td><td width="20%">0xC0 0x7B</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_RSA_AES_128_CCM</td><td width="20%">0xC0 0x9C</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_RSA_AES_256_CCM</td><td width="20%">0xC0 0x9D</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_RSA_AES_128_CCM_8</td><td width="20%">0xC0 0xA0</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_RSA_AES_256_CCM_8</td><td width="20%">0xC0 0xA1</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DHE_DSS_ARCFOUR_128_SHA1</td><td width="20%">0x00 0x66</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_DHE_DSS_3DES_EDE_CBC_SHA1</td><td width="20%">0x00 0x13</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_DHE_DSS_AES_128_CBC_SHA1</td><td width="20%">0x00 0x32</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_DHE_DSS_AES_256_CBC_SHA1</td><td width="20%">0x00 0x38</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_DHE_DSS_CAMELLIA_128_CBC_SHA256</td><td width="20%">0x00 0xBD</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DHE_DSS_CAMELLIA_256_CBC_SHA256</td><td width="20%">0x00 0xC3</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DHE_DSS_CAMELLIA_128_CBC_SHA1</td><td width="20%">0x00 0x44</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_DHE_DSS_CAMELLIA_256_CBC_SHA1</td><td width="20%">0x00 0x87</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_DHE_DSS_AES_128_CBC_SHA256</td><td width="20%">0x00 0x40</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DHE_DSS_AES_256_CBC_SHA256</td><td width="20%">0x00 0x6A</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DHE_DSS_AES_128_GCM_SHA256</td><td width="20%">0x00 0xA2</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DHE_DSS_AES_256_GCM_SHA384</td><td width="20%">0x00 0xA3</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DHE_DSS_CAMELLIA_128_GCM_SHA256</td><td width="20%">0xC0 0x80</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DHE_DSS_CAMELLIA_256_GCM_SHA384</td><td width="20%">0xC0 0x81</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DHE_RSA_3DES_EDE_CBC_SHA1</td><td width="20%">0x00 0x16</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_DHE_RSA_AES_128_CBC_SHA1</td><td width="20%">0x00 0x33</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_DHE_RSA_AES_256_CBC_SHA1</td><td width="20%">0x00 0x39</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_DHE_RSA_CAMELLIA_128_CBC_SHA256</td><td width="20%">0x00 0xBE</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DHE_RSA_CAMELLIA_256_CBC_SHA256</td><td width="20%">0x00 0xC4</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DHE_RSA_CAMELLIA_128_CBC_SHA1</td><td width="20%">0x00 0x45</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_DHE_RSA_CAMELLIA_256_CBC_SHA1</td><td width="20%">0x00 0x88</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_DHE_RSA_AES_128_CBC_SHA256</td><td width="20%">0x00 0x67</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DHE_RSA_AES_256_CBC_SHA256</td><td width="20%">0x00 0x6B</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DHE_RSA_AES_128_GCM_SHA256</td><td width="20%">0x00 0x9E</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DHE_RSA_AES_256_GCM_SHA384</td><td width="20%">0x00 0x9F</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DHE_RSA_CAMELLIA_128_GCM_SHA256</td><td width="20%">0xC0 0x7C</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DHE_RSA_CAMELLIA_256_GCM_SHA384</td><td width="20%">0xC0 0x7D</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DHE_RSA_CHACHA20_POLY1305</td><td width="20%">0xCC 0xAA</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DHE_RSA_AES_128_CCM</td><td width="20%">0xC0 0x9E</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DHE_RSA_AES_256_CCM</td><td width="20%">0xC0 0x9F</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DHE_RSA_AES_128_CCM_8</td><td width="20%">0xC0 0xA2</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DHE_RSA_AES_256_CCM_8</td><td width="20%">0xC0 0xA3</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_ECDHE_RSA_NULL_SHA1</td><td width="20%">0xC0 0x10</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_ECDHE_RSA_3DES_EDE_CBC_SHA1</td><td width="20%">0xC0 0x12</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_ECDHE_RSA_AES_128_CBC_SHA1</td><td width="20%">0xC0 0x13</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_ECDHE_RSA_AES_256_CBC_SHA1</td><td width="20%">0xC0 0x14</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_ECDHE_RSA_AES_256_CBC_SHA384</td><td width="20%">0xC0 0x28</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_ECDHE_RSA_ARCFOUR_128_SHA1</td><td width="20%">0xC0 0x11</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_ECDHE_RSA_CAMELLIA_128_CBC_SHA256</td><td width="20%">0xC0 0x76</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_ECDHE_RSA_CAMELLIA_256_CBC_SHA384</td><td width="20%">0xC0 0x77</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_ECDHE_ECDSA_NULL_SHA1</td><td width="20%">0xC0 0x06</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_ECDHE_ECDSA_3DES_EDE_CBC_SHA1</td><td width="20%">0xC0 0x08</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_ECDHE_ECDSA_AES_128_CBC_SHA1</td><td width="20%">0xC0 0x09</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_ECDHE_ECDSA_AES_256_CBC_SHA1</td><td width="20%">0xC0 0x0A</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_ECDHE_ECDSA_ARCFOUR_128_SHA1</td><td width="20%">0xC0 0x07</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_ECDHE_ECDSA_CAMELLIA_128_CBC_SHA256</td><td width="20%">0xC0 0x72</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_ECDHE_ECDSA_CAMELLIA_256_CBC_SHA384</td><td width="20%">0xC0 0x73</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_ECDHE_ECDSA_AES_128_CBC_SHA256</td><td width="20%">0xC0 0x23</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_ECDHE_RSA_AES_128_CBC_SHA256</td><td width="20%">0xC0 0x27</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_ECDHE_ECDSA_CAMELLIA_128_GCM_SHA256</td><td width="20%">0xC0 0x86</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_ECDHE_ECDSA_CAMELLIA_256_GCM_SHA384</td><td width="20%">0xC0 0x87</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_ECDHE_ECDSA_AES_128_GCM_SHA256</td><td width="20%">0xC0 0x2B</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_ECDHE_ECDSA_AES_256_GCM_SHA384</td><td width="20%">0xC0 0x2C</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_ECDHE_RSA_AES_128_GCM_SHA256</td><td width="20%">0xC0 0x2F</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_ECDHE_RSA_AES_256_GCM_SHA384</td><td width="20%">0xC0 0x30</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_ECDHE_ECDSA_AES_256_CBC_SHA384</td><td width="20%">0xC0 0x24</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_ECDHE_RSA_CAMELLIA_128_GCM_SHA256</td><td width="20%">0xC0 0x8A</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_ECDHE_RSA_CAMELLIA_256_GCM_SHA384</td><td width="20%">0xC0 0x8B</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_ECDHE_RSA_CHACHA20_POLY1305</td><td width="20%">0xCC 0xA8</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_ECDHE_ECDSA_CHACHA20_POLY1305</td><td width="20%">0xCC 0xA9</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_ECDHE_ECDSA_AES_128_CCM</td><td width="20%">0xC0 0xAC</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_ECDHE_ECDSA_AES_256_CCM</td><td width="20%">0xC0 0xAD</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_ECDHE_ECDSA_AES_128_CCM_8</td><td width="20%">0xC0 0xAE</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_ECDHE_ECDSA_AES_256_CCM_8</td><td width="20%">0xC0 0xAF</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_ECDHE_PSK_3DES_EDE_CBC_SHA1</td><td width="20%">0xC0 0x34</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_ECDHE_PSK_AES_128_CBC_SHA1</td><td width="20%">0xC0 0x35</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_ECDHE_PSK_AES_256_CBC_SHA1</td><td width="20%">0xC0 0x36</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_ECDHE_PSK_AES_128_CBC_SHA256</td><td width="20%">0xC0 0x37</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_ECDHE_PSK_AES_256_CBC_SHA384</td><td width="20%">0xC0 0x38</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_ECDHE_PSK_ARCFOUR_128_SHA1</td><td width="20%">0xC0 0x33</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_ECDHE_PSK_NULL_SHA1</td><td width="20%">0xC0 0x39</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_ECDHE_PSK_NULL_SHA256</td><td width="20%">0xC0 0x3A</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_ECDHE_PSK_NULL_SHA384</td><td width="20%">0xC0 0x3B</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_ECDHE_PSK_CAMELLIA_128_CBC_SHA256</td><td width="20%">0xC0 0x9A</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_ECDHE_PSK_CAMELLIA_256_CBC_SHA384</td><td width="20%">0xC0 0x9B</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_PSK_ARCFOUR_128_SHA1</td><td width="20%">0x00 0x8A</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_PSK_3DES_EDE_CBC_SHA1</td><td width="20%">0x00 0x8B</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_PSK_AES_128_CBC_SHA1</td><td width="20%">0x00 0x8C</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_PSK_AES_256_CBC_SHA1</td><td width="20%">0x00 0x8D</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_PSK_AES_128_CBC_SHA256</td><td width="20%">0x00 0xAE</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_PSK_AES_256_GCM_SHA384</td><td width="20%">0x00 0xA9</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_PSK_CAMELLIA_128_GCM_SHA256</td><td width="20%">0xC0 0x8E</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_PSK_CAMELLIA_256_GCM_SHA384</td><td width="20%">0xC0 0x8F</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_PSK_AES_128_GCM_SHA256</td><td width="20%">0x00 0xA8</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_PSK_NULL_SHA1</td><td width="20%">0x00 0x2C</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_PSK_NULL_SHA256</td><td width="20%">0x00 0xB0</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_PSK_CAMELLIA_128_CBC_SHA256</td><td width="20%">0xC0 0x94</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_PSK_CAMELLIA_256_CBC_SHA384</td><td width="20%">0xC0 0x95</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_PSK_AES_256_CBC_SHA384</td><td width="20%">0x00 0xAF</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_PSK_NULL_SHA384</td><td width="20%">0x00 0xB1</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_RSA_PSK_ARCFOUR_128_SHA1</td><td width="20%">0x00 0x92</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_RSA_PSK_3DES_EDE_CBC_SHA1</td><td width="20%">0x00 0x93</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_RSA_PSK_AES_128_CBC_SHA1</td><td width="20%">0x00 0x94</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_RSA_PSK_AES_256_CBC_SHA1</td><td width="20%">0x00 0x95</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_RSA_PSK_CAMELLIA_128_GCM_SHA256</td><td width="20%">0xC0 0x92</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_RSA_PSK_CAMELLIA_256_GCM_SHA384</td><td width="20%">0xC0 0x93</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_RSA_PSK_AES_128_GCM_SHA256</td><td width="20%">0x00 0xAC</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_RSA_PSK_AES_128_CBC_SHA256</td><td width="20%">0x00 0xB6</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_RSA_PSK_NULL_SHA1</td><td width="20%">0x00 0x2E</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_RSA_PSK_NULL_SHA256</td><td width="20%">0x00 0xB8</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_RSA_PSK_AES_256_GCM_SHA384</td><td width="20%">0x00 0xAD</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_RSA_PSK_AES_256_CBC_SHA384</td><td width="20%">0x00 0xB7</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_RSA_PSK_NULL_SHA384</td><td width="20%">0x00 0xB9</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_RSA_PSK_CAMELLIA_128_CBC_SHA256</td><td width="20%">0xC0 0x98</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_RSA_PSK_CAMELLIA_256_CBC_SHA384</td><td width="20%">0xC0 0x99</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DHE_PSK_ARCFOUR_128_SHA1</td><td width="20%">0x00 0x8E</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_DHE_PSK_3DES_EDE_CBC_SHA1</td><td width="20%">0x00 0x8F</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_DHE_PSK_AES_128_CBC_SHA1</td><td width="20%">0x00 0x90</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_DHE_PSK_AES_256_CBC_SHA1</td><td width="20%">0x00 0x91</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_DHE_PSK_AES_128_CBC_SHA256</td><td width="20%">0x00 0xB2</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DHE_PSK_AES_128_GCM_SHA256</td><td width="20%">0x00 0xAA</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DHE_PSK_NULL_SHA1</td><td width="20%">0x00 0x2D</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_DHE_PSK_NULL_SHA256</td><td width="20%">0x00 0xB4</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DHE_PSK_NULL_SHA384</td><td width="20%">0x00 0xB5</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DHE_PSK_AES_256_CBC_SHA384</td><td width="20%">0x00 0xB3</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DHE_PSK_AES_256_GCM_SHA384</td><td width="20%">0x00 0xAB</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DHE_PSK_CAMELLIA_128_CBC_SHA256</td><td width="20%">0xC0 0x96</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DHE_PSK_CAMELLIA_256_CBC_SHA384</td><td width="20%">0xC0 0x97</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DHE_PSK_CAMELLIA_128_GCM_SHA256</td><td width="20%">0xC0 0x90</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DHE_PSK_CAMELLIA_256_GCM_SHA384</td><td width="20%">0xC0 0x91</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_PSK_AES_128_CCM</td><td width="20%">0xC0 0xA4</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_PSK_AES_256_CCM</td><td width="20%">0xC0 0xA5</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DHE_PSK_AES_128_CCM</td><td width="20%">0xC0 0xA6</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DHE_PSK_AES_256_CCM</td><td width="20%">0xC0 0xA7</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_PSK_AES_128_CCM_8</td><td width="20%">0xC0 0xA8</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_PSK_AES_256_CCM_8</td><td width="20%">0xC0 0xA9</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DHE_PSK_AES_128_CCM_8</td><td width="20%">0xC0 0xAA</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DHE_PSK_AES_256_CCM_8</td><td width="20%">0xC0 0xAB</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DHE_PSK_CHACHA20_POLY1305</td><td width="20%">0xCC 0xAD</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_ECDHE_PSK_CHACHA20_POLY1305</td><td width="20%">0xCC 0xAC</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_RSA_PSK_CHACHA20_POLY1305</td><td width="20%">0xCC 0xAE</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_PSK_CHACHA20_POLY1305</td><td width="20%">0xCC 0xAB</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DH_ANON_ARCFOUR_128_MD5</td><td width="20%">0x00 0x18</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_DH_ANON_3DES_EDE_CBC_SHA1</td><td width="20%">0x00 0x1B</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_DH_ANON_AES_128_CBC_SHA1</td><td width="20%">0x00 0x34</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_DH_ANON_AES_256_CBC_SHA1</td><td width="20%">0x00 0x3A</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_DH_ANON_CAMELLIA_128_CBC_SHA256</td><td width="20%">0x00 0xBF</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DH_ANON_CAMELLIA_256_CBC_SHA256</td><td width="20%">0x00 0xC5</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DH_ANON_CAMELLIA_128_CBC_SHA1</td><td width="20%">0x00 0x46</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_DH_ANON_CAMELLIA_256_CBC_SHA1</td><td width="20%">0x00 0x89</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_DH_ANON_AES_128_CBC_SHA256</td><td width="20%">0x00 0x6C</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DH_ANON_AES_256_CBC_SHA256</td><td width="20%">0x00 0x6D</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DH_ANON_AES_128_GCM_SHA256</td><td width="20%">0x00 0xA6</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DH_ANON_AES_256_GCM_SHA384</td><td width="20%">0x00 0xA7</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DH_ANON_CAMELLIA_128_GCM_SHA256</td><td width="20%">0xC0 0x84</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_DH_ANON_CAMELLIA_256_GCM_SHA384</td><td width="20%">0xC0 0x85</td><td width="20%">TLS1.2</td></tr>
<tr><td width="60%">TLS_ECDH_ANON_NULL_SHA1</td><td width="20%">0xC0 0x15</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_ECDH_ANON_3DES_EDE_CBC_SHA1</td><td width="20%">0xC0 0x17</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_ECDH_ANON_AES_128_CBC_SHA1</td><td width="20%">0xC0 0x18</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_ECDH_ANON_AES_256_CBC_SHA1</td><td width="20%">0xC0 0x19</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_ECDH_ANON_ARCFOUR_128_SHA1</td><td width="20%">0xC0 0x16</td><td width="20%">TLS1.0</td></tr>
<tr><td width="60%">TLS_GOSTR341112_256_28147_CNT_IMIT</td><td width="20%">0xC1 0x02</td><td width="20%">TLS1.2</td></tr>
</tbody>
</table>


<h3 class="heading" id="Certificate-types"><span>Certificate types<a class="copiable-link" href="#Certificate-types"> &para;</a></span></h3>
<dl class="table">
<dt><code class="code">X.509</code></dt>
<dt><code class="code">Raw Public Key</code></dt>
</dl>

<h3 class="heading" id="Protocols"><span>Protocols<a class="copiable-link" href="#Protocols"> &para;</a></span></h3>
<dl class="table">
<dt><code class="code">TLS1.0</code></dt>
<dt><code class="code">TLS1.1</code></dt>
<dt><code class="code">TLS1.2</code></dt>
<dt><code class="code">TLS1.3</code></dt>
<dt><code class="code">DTLS0.9</code></dt>
<dt><code class="code">DTLS1.0</code></dt>
<dt><code class="code">DTLS1.2</code></dt>
</dl>

<h3 class="heading" id="Ciphers"><span>Ciphers<a class="copiable-link" href="#Ciphers"> &para;</a></span></h3>
<dl class="table">
<dt><code class="code">AES-256-CBC</code></dt>
<dt><code class="code">AES-192-CBC</code></dt>
<dt><code class="code">AES-128-CBC</code></dt>
<dt><code class="code">AES-128-GCM</code></dt>
<dt><code class="code">AES-192-GCM</code></dt>
<dt><code class="code">AES-256-GCM</code></dt>
<dt><code class="code">AES-128-CCM</code></dt>
<dt><code class="code">AES-256-CCM</code></dt>
<dt><code class="code">AES-128-CCM-8</code></dt>
<dt><code class="code">AES-256-CCM-8</code></dt>
<dt><code class="code">ARCFOUR-128</code></dt>
<dt><code class="code">ESTREAM-SALSA20-256</code></dt>
<dt><code class="code">SALSA20-256</code></dt>
<dt><code class="code">CHACHA20-32</code></dt>
<dt><code class="code">CHACHA20-64</code></dt>
<dt><code class="code">CAMELLIA-256-CBC</code></dt>
<dt><code class="code">CAMELLIA-192-CBC</code></dt>
<dt><code class="code">CAMELLIA-128-CBC</code></dt>
<dt><code class="code">CHACHA20-POLY1305</code></dt>
<dt><code class="code">CAMELLIA-128-GCM</code></dt>
<dt><code class="code">CAMELLIA-256-GCM</code></dt>
<dt><code class="code">GOST28147-TC26Z-CFB</code></dt>
<dt><code class="code">GOST28147-CPA-CFB</code></dt>
<dt><code class="code">GOST28147-CPB-CFB</code></dt>
<dt><code class="code">GOST28147-CPC-CFB</code></dt>
<dt><code class="code">GOST28147-CPD-CFB</code></dt>
<dt><code class="code">AES-128-CFB8</code></dt>
<dt><code class="code">AES-192-CFB8</code></dt>
<dt><code class="code">AES-256-CFB8</code></dt>
<dt><code class="code">AES-128-CFB</code></dt>
<dt><code class="code">AES-192-CFB</code></dt>
<dt><code class="code">AES-256-CFB</code></dt>
<dt><code class="code">AES-128-XTS</code></dt>
<dt><code class="code">AES-256-XTS</code></dt>
<dt><code class="code">AES-128-SIV</code></dt>
<dt><code class="code">AES-256-SIV</code></dt>
<dt><code class="code">AES-128-SIV-GCM</code></dt>
<dt><code class="code">AES-256-SIV-GCM</code></dt>
<dt><code class="code">GOST28147-TC26Z-CNT</code></dt>
<dt><code class="code">MAGMA-CTR-ACPKM</code></dt>
<dt><code class="code">KUZNYECHIK-CTR-ACPKM</code></dt>
<dt><code class="code">3DES-CBC</code></dt>
<dt><code class="code">DES-CBC</code></dt>
<dt><code class="code">RC2-40</code></dt>
<dt><code class="code">NULL</code></dt>
</dl>

<h3 class="heading" id="MAC-algorithms"><span>MAC algorithms<a class="copiable-link" href="#MAC-algorithms"> &para;</a></span></h3>
<dl class="table">
<dt><code class="code">SHA1</code></dt>
<dt><code class="code">SHA256</code></dt>
<dt><code class="code">SHA384</code></dt>
<dt><code class="code">SHA512</code></dt>
<dt><code class="code">SHA224</code></dt>
<dt><code class="code">UMAC-96</code></dt>
<dt><code class="code">UMAC-128</code></dt>
<dt><code class="code">AEAD</code></dt>
<dt><code class="code">MD5</code></dt>
<dt><code class="code">GOSTR341194</code></dt>
<dt><code class="code">STREEBOG-256</code></dt>
<dt><code class="code">STREEBOG-512</code></dt>
<dt><code class="code">AES-CMAC-128</code></dt>
<dt><code class="code">AES-CMAC-256</code></dt>
<dt><code class="code">AES-GMAC-128</code></dt>
<dt><code class="code">AES-GMAC-192</code></dt>
<dt><code class="code">AES-GMAC-256</code></dt>
<dt><code class="code">GOST28147-TC26Z-IMIT</code></dt>
<dt><code class="code">OMAC-MAGMA</code></dt>
<dt><code class="code">OMAC-KUZNYECHIK</code></dt>
<dt><code class="code">PBMAC1</code></dt>
</dl>

<h3 class="heading" id="Key-exchange-methods"><span>Key exchange methods<a class="copiable-link" href="#Key-exchange-methods"> &para;</a></span></h3>
<dl class="table">
<dt><code class="code">ECDHE-RSA</code></dt>
<dt><code class="code">ECDHE-ECDSA</code></dt>
<dt><code class="code">RSA</code></dt>
<dt><code class="code">DHE-RSA</code></dt>
<dt><code class="code">DHE-DSS</code></dt>
<dt><code class="code">PSK</code></dt>
<dt><code class="code">RSA-PSK</code></dt>
<dt><code class="code">DHE-PSK</code></dt>
<dt><code class="code">ECDHE-PSK</code></dt>
<dt><code class="code">ANON-DH</code></dt>
<dt><code class="code">ANON-ECDH</code></dt>
<dt><code class="code">VKO-GOST-12</code></dt>
<dt><code class="code">RSA-EXPORT</code></dt>
</dl>

<h3 class="heading" id="Public-key-algorithms-2"><span>Public key algorithms<a class="copiable-link" href="#Public-key-algorithms-2"> &para;</a></span></h3>
<dl class="table">
<dt><code class="code">RSA</code></dt>
<dt><code class="code">RSA-PSS</code></dt>
<dt><code class="code">RSA-OAEP</code></dt>
<dt><code class="code">RSA</code></dt>
<dt><code class="code">DSA</code></dt>
<dt><code class="code">GOST R 34.10-2012-512</code></dt>
<dt><code class="code">GOST R 34.10-2012-256</code></dt>
<dt><code class="code">GOST R 34.10-2001</code></dt>
<dt><code class="code">EC/ECDSA</code></dt>
<dt><code class="code">EdDSA (Ed25519)</code></dt>
<dt><code class="code">EdDSA (Ed448)</code></dt>
<dt><code class="code">DH</code></dt>
<dt><code class="code">ECDH (X25519)</code></dt>
<dt><code class="code">ECDH (X448)</code></dt>
</dl>

<h3 class="heading" id="Public-key-signature-algorithms"><span>Public key signature algorithms<a class="copiable-link" href="#Public-key-signature-algorithms"> &para;</a></span></h3>
<dl class="table">
<dt><code class="code">RSA-SHA256</code></dt>
<dt><code class="code">RSA-SHA384</code></dt>
<dt><code class="code">RSA-SHA512</code></dt>
<dt><code class="code">RSA-PSS-SHA256</code></dt>
<dt><code class="code">RSA-PSS-RSAE-SHA256</code></dt>
<dt><code class="code">RSA-PSS-SHA384</code></dt>
<dt><code class="code">RSA-PSS-RSAE-SHA384</code></dt>
<dt><code class="code">RSA-PSS-SHA512</code></dt>
<dt><code class="code">RSA-PSS-RSAE-SHA512</code></dt>
<dt><code class="code">EdDSA-Ed25519</code></dt>
<dt><code class="code">EdDSA-Ed448</code></dt>
<dt><code class="code">ECDSA-SHA256</code></dt>
<dt><code class="code">ECDSA-SHA384</code></dt>
<dt><code class="code">ECDSA-SHA512</code></dt>
<dt><code class="code">ECDSA-SECP256R1-SHA256</code></dt>
<dt><code class="code">ECDSA-SECP384R1-SHA384</code></dt>
<dt><code class="code">ECDSA-SECP521R1-SHA512</code></dt>
<dt><code class="code">ECDSA-SHA3-224</code></dt>
<dt><code class="code">ECDSA-SHA3-256</code></dt>
<dt><code class="code">ECDSA-SHA3-384</code></dt>
<dt><code class="code">ECDSA-SHA3-512</code></dt>
<dt><code class="code">RSA-SHA3-224</code></dt>
<dt><code class="code">RSA-SHA3-256</code></dt>
<dt><code class="code">RSA-SHA3-384</code></dt>
<dt><code class="code">RSA-SHA3-512</code></dt>
<dt><code class="code">DSA-SHA3-224</code></dt>
<dt><code class="code">DSA-SHA3-256</code></dt>
<dt><code class="code">DSA-SHA3-384</code></dt>
<dt><code class="code">DSA-SHA3-512</code></dt>
<dt><code class="code">RSA-RAW</code></dt>
<dt><code class="code">RSA-SHA1</code></dt>
<dt><code class="code">RSA-SHA1</code></dt>
<dt><code class="code">RSA-SHA224</code></dt>
<dt><code class="code">RSA-RMD160</code></dt>
<dt><code class="code">DSA-SHA1</code></dt>
<dt><code class="code">DSA-SHA1</code></dt>
<dt><code class="code">DSA-SHA224</code></dt>
<dt><code class="code">DSA-SHA256</code></dt>
<dt><code class="code">RSA-MD5</code></dt>
<dt><code class="code">RSA-MD5</code></dt>
<dt><code class="code">RSA-MD2</code></dt>
<dt><code class="code">ECDSA-SHA1</code></dt>
<dt><code class="code">ECDSA-SHA224</code></dt>
<dt><code class="code">GOSTR341012-512</code></dt>
<dt><code class="code">GOSTR341012-256</code></dt>
<dt><code class="code">GOSTR341001</code></dt>
<dt><code class="code">DSA-SHA384</code></dt>
<dt><code class="code">DSA-SHA512</code></dt>
</dl>

<h3 class="heading" id="Groups"><span>Groups<a class="copiable-link" href="#Groups"> &para;</a></span></h3>
<dl class="table">
<dt><code class="code">SECP256R1</code></dt>
<dt><code class="code">SECP384R1</code></dt>
<dt><code class="code">SECP521R1</code></dt>
<dt><code class="code">X25519</code></dt>
<dt><code class="code">GC256B</code></dt>
<dt><code class="code">GC512A</code></dt>
<dt><code class="code">X448</code></dt>
<dt><code class="code">FFDHE2048</code></dt>
<dt><code class="code">FFDHE3072</code></dt>
<dt><code class="code">FFDHE4096</code></dt>
<dt><code class="code">FFDHE6144</code></dt>
<dt><code class="code">FFDHE8192</code></dt>
</dl>


<hr>
</div>
<div class="appendix-level-extent" id="API-reference">
<div class="nav-panel">
<p>
Next: <a href="#Copying-Information" accesskey="n" rel="next">Copying Information</a>, Previous: <a href="#Supported-ciphersuites" accesskey="p" rel="prev">Supported Ciphersuites</a>, Up: <a href="#Top" accesskey="u" rel="up">GnuTLS</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h2 class="appendix" id="API-reference-1"><span>Appendix E API reference<a class="copiable-link" href="#API-reference-1"> &para;</a></span></h2>
<a class="index-entry-id" id="index-API-reference"></a>


<ul class="mini-toc">
<li><a href="#Core-TLS-API" accesskey="1">Core TLS API</a></li>
<li><a href="#Datagram-TLS-API" accesskey="2">Datagram TLS API</a></li>
<li><a href="#X509-certificate-API" accesskey="3"><abbr class="acronym">X.509</abbr> certificate API</a></li>
<li><a href="#PKCS-7-API" accesskey="4"><abbr class="acronym">PKCS</abbr> 7 API</a></li>
<li><a href="#OCSP-API" accesskey="5"><abbr class="acronym">OCSP</abbr> API</a></li>
<li><a href="#PKCS-12-API" accesskey="6">PKCS 12 API</a></li>
<li><a href="#PKCS-11-API" accesskey="7">Hardware token via PKCS 11 API</a></li>
<li><a href="#TPM-API" accesskey="8">TPM API</a></li>
<li><a href="#Abstract-key-API" accesskey="9">Abstract key API</a></li>
<li><a href="#Socket-specific-API">Socket specific API</a></li>
<li><a href="#DANE-API">DANE API</a></li>
<li><a href="#Cryptographic-API">Cryptographic API</a></li>
<li><a href="#Compatibility-API">Compatibility API</a></li>
</ul>
<hr>
<div class="section-level-extent" id="Core-TLS-API">
<div class="nav-panel">
<p>
Next: <a href="#Datagram-TLS-API" accesskey="n" rel="next">Datagram TLS API</a>, Up: <a href="#API-reference" accesskey="u" rel="up">API reference</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Core-TLS-API-1"><span>E.1 Core TLS API<a class="copiable-link" href="#Core-TLS-API-1"> &para;</a></span></h3>

<p>The prototypes for the following functions lie in
<samp class="file">gnutls/gnutls.h</samp>.
</p>

<h4 class="subheading" id="gnutls_005falert_005fget-1"><span>gnutls_alert_get<a class="copiable-link" href="#gnutls_005falert_005fget-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005falert_005fget"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005falert_005fget-1"><span class="category-def">Function: </span><span><code class="def-type">gnutls_alert_description_t</code> <strong class="def-name">gnutls_alert_get</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005falert_005fget-1"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>This function will return the last alert number received.  This
function should be called when <code class="code">GNUTLS_E_WARNING_ALERT_RECEIVED</code>  or
<code class="code">GNUTLS_E_FATAL_ALERT_RECEIVED</code>  errors are returned by a gnutls
function.  The peer may send alerts if he encounters an error.
If no alert has been received the returned value is undefined.
</p>
<p><strong class="strong">Returns:</strong> the last alert received, a
<code class="code">gnutls_alert_description_t</code>  value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005falert_005fget_005fname-1"><span>gnutls_alert_get_name<a class="copiable-link" href="#gnutls_005falert_005fget_005fname-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005falert_005fget_005fname"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005falert_005fget_005fname-1"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_alert_get_name</strong> <code class="def-code-arguments">(gnutls_alert_description_t <var class="var">alert</var>)</code><a class="copiable-link" href="#index-gnutls_005falert_005fget_005fname-1"> &para;</a></span></dt>
<dd><p><var class="var">alert</var>: is an alert number.
</p>
<p>This function will return a string that describes the given alert
number, or <code class="code">NULL</code> .  See <code class="code">gnutls_alert_get()</code> .
</p>
<p><strong class="strong">Returns:</strong> string corresponding to <code class="code">gnutls_alert_description_t</code>  value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005falert_005fget_005fstrname-1"><span>gnutls_alert_get_strname<a class="copiable-link" href="#gnutls_005falert_005fget_005fstrname-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005falert_005fget_005fstrname"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005falert_005fget_005fstrname"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_alert_get_strname</strong> <code class="def-code-arguments">(gnutls_alert_description_t <var class="var">alert</var>)</code><a class="copiable-link" href="#index-gnutls_005falert_005fget_005fstrname"> &para;</a></span></dt>
<dd><p><var class="var">alert</var>: is an alert number.
</p>
<p>This function will return a string of the name of the alert.
</p>
<p><strong class="strong">Returns:</strong> string corresponding to <code class="code">gnutls_alert_description_t</code>  value.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005falert_005fsend-1"><span>gnutls_alert_send<a class="copiable-link" href="#gnutls_005falert_005fsend-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005falert_005fsend"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005falert_005fsend-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_alert_send</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_alert_level_t <var class="var">level</var>, gnutls_alert_description_t <var class="var">desc</var>)</code><a class="copiable-link" href="#index-gnutls_005falert_005fsend-1"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">level</var>: is the level of the alert
</p>
<p><var class="var">desc</var>: is the alert description
</p>
<p>This function will send an alert to the peer in order to inform
him of something important (eg. his Certificate could not be verified).
If the alert level is Fatal then the peer is expected to close the
connection, otherwise he may ignore the alert and continue.
</p>
<p>The error code of the underlying record send function will be
returned, so you may also receive <code class="code">GNUTLS_E_INTERRUPTED</code>  or
<code class="code">GNUTLS_E_AGAIN</code>  as well.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise
an error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005falert_005fsend_005fappropriate-1"><span>gnutls_alert_send_appropriate<a class="copiable-link" href="#gnutls_005falert_005fsend_005fappropriate-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005falert_005fsend_005fappropriate"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005falert_005fsend_005fappropriate"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_alert_send_appropriate</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, int <var class="var">err</var>)</code><a class="copiable-link" href="#index-gnutls_005falert_005fsend_005fappropriate"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">err</var>: is an error code returned by another GnuTLS function
</p>
<p>Sends an alert to the peer depending on the error code returned by
a gnutls function. This function will call <code class="code">gnutls_error_to_alert()</code> 
to determine the appropriate alert to send.
</p>
<p>This function may also return <code class="code">GNUTLS_E_AGAIN</code> , or
<code class="code">GNUTLS_E_INTERRUPTED</code> .
</p>
<p>This function historically was always sending an alert to the
peer, even if  <code class="code">err</code> was inappropriate to respond with an alert
(e.g., <code class="code">GNUTLS_E_SUCCESS</code> ). Since 3.6.6 this function returns
success without transmitting any data on error codes that
should not result to an alert.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise
an error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005falert_005fset_005fread_005ffunction-1"><span>gnutls_alert_set_read_function<a class="copiable-link" href="#gnutls_005falert_005fset_005fread_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005falert_005fset_005fread_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005falert_005fset_005fread_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_alert_set_read_function</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_alert_read_func <var class="var">func</var>)</code><a class="copiable-link" href="#index-gnutls_005falert_005fset_005fread_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is <code class="code">gnutls_session_t</code>  type
</p>
<p><var class="var">func</var>: is the function to be called
</p>
<p>This function will set a callback to be called when an alert
message is being sent.
</p>
<p><strong class="strong">Since:</strong> 3.7.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005falpn_005fget_005fselected_005fprotocol-1"><span>gnutls_alpn_get_selected_protocol<a class="copiable-link" href="#gnutls_005falpn_005fget_005fselected_005fprotocol-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005falpn_005fget_005fselected_005fprotocol"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005falpn_005fget_005fselected_005fprotocol"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_alpn_get_selected_protocol</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_datum_t * <var class="var">protocol</var>)</code><a class="copiable-link" href="#index-gnutls_005falpn_005fget_005fselected_005fprotocol"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">protocol</var>: will hold the protocol name
</p>
<p>This function allows you to get the negotiated protocol name. The
returned protocol should be treated as opaque, constant value and
only valid during the session life.
</p>
<p>The selected protocol is the first supported by the list sent
by the client.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned.
</p>
<p>Since 3.2.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005falpn_005fset_005fprotocols-1"><span>gnutls_alpn_set_protocols<a class="copiable-link" href="#gnutls_005falpn_005fset_005fprotocols-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005falpn_005fset_005fprotocols"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005falpn_005fset_005fprotocols"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_alpn_set_protocols</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, const gnutls_datum_t * <var class="var">protocols</var>, unsigned <var class="var">protocols_size</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005falpn_005fset_005fprotocols"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">protocols</var>: is the protocol names to add.
</p>
<p><var class="var">protocols_size</var>: the number of protocols to add.
</p>
<p><var class="var">flags</var>: zero or a sequence of <code class="code">gnutls_alpn_flags_t</code> 
</p>
<p>This function is to be used by both clients and servers, to declare
the supported ALPN protocols, which are used during negotiation with peer.
</p>
<p>See <code class="code">gnutls_alpn_flags_t</code>  description for the documentation of available
flags.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned.
</p>
<p>Since 3.2.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fanon_005fallocate_005fclient_005fcredentials-1"><span>gnutls_anon_allocate_client_credentials<a class="copiable-link" href="#gnutls_005fanon_005fallocate_005fclient_005fcredentials-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fanon_005fallocate_005fclient_005fcredentials"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fanon_005fallocate_005fclient_005fcredentials"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_anon_allocate_client_credentials</strong> <code class="def-code-arguments">(gnutls_anon_client_credentials_t * <var class="var">sc</var>)</code><a class="copiable-link" href="#index-gnutls_005fanon_005fallocate_005fclient_005fcredentials"> &para;</a></span></dt>
<dd><p><var class="var">sc</var>: is a pointer to a <code class="code">gnutls_anon_client_credentials_t</code>  type.
</p>
<p>Allocate a gnutls_anon_client_credentials_t structure.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, or an error code.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fanon_005fallocate_005fserver_005fcredentials-1"><span>gnutls_anon_allocate_server_credentials<a class="copiable-link" href="#gnutls_005fanon_005fallocate_005fserver_005fcredentials-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fanon_005fallocate_005fserver_005fcredentials"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fanon_005fallocate_005fserver_005fcredentials"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_anon_allocate_server_credentials</strong> <code class="def-code-arguments">(gnutls_anon_server_credentials_t * <var class="var">sc</var>)</code><a class="copiable-link" href="#index-gnutls_005fanon_005fallocate_005fserver_005fcredentials"> &para;</a></span></dt>
<dd><p><var class="var">sc</var>: is a pointer to a <code class="code">gnutls_anon_server_credentials_t</code>  type.
</p>
<p>Allocate a gnutls_anon_server_credentials_t structure.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, or an error code.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fanon_005ffree_005fclient_005fcredentials-1"><span>gnutls_anon_free_client_credentials<a class="copiable-link" href="#gnutls_005fanon_005ffree_005fclient_005fcredentials-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fanon_005ffree_005fclient_005fcredentials"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fanon_005ffree_005fclient_005fcredentials"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_anon_free_client_credentials</strong> <code class="def-code-arguments">(gnutls_anon_client_credentials_t <var class="var">sc</var>)</code><a class="copiable-link" href="#index-gnutls_005fanon_005ffree_005fclient_005fcredentials"> &para;</a></span></dt>
<dd><p><var class="var">sc</var>: is a <code class="code">gnutls_anon_client_credentials_t</code>  type.
</p>
<p>Free a gnutls_anon_client_credentials_t structure.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fanon_005ffree_005fserver_005fcredentials-1"><span>gnutls_anon_free_server_credentials<a class="copiable-link" href="#gnutls_005fanon_005ffree_005fserver_005fcredentials-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fanon_005ffree_005fserver_005fcredentials"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fanon_005ffree_005fserver_005fcredentials"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_anon_free_server_credentials</strong> <code class="def-code-arguments">(gnutls_anon_server_credentials_t <var class="var">sc</var>)</code><a class="copiable-link" href="#index-gnutls_005fanon_005ffree_005fserver_005fcredentials"> &para;</a></span></dt>
<dd><p><var class="var">sc</var>: is a <code class="code">gnutls_anon_server_credentials_t</code>  type.
</p>
<p>Free a gnutls_anon_server_credentials_t structure.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fanon_005fset_005fparams_005ffunction-1"><span>gnutls_anon_set_params_function<a class="copiable-link" href="#gnutls_005fanon_005fset_005fparams_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fanon_005fset_005fparams_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fanon_005fset_005fparams_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_anon_set_params_function</strong> <code class="def-code-arguments">(gnutls_anon_server_credentials_t <var class="var">res</var>, gnutls_params_function * <var class="var">func</var>)</code><a class="copiable-link" href="#index-gnutls_005fanon_005fset_005fparams_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">res</var>: is a gnutls_anon_server_credentials_t type
</p>
<p><var class="var">func</var>: is the function to be called
</p>
<p>This function will set a callback in order for the server to get
the Diffie-Hellman or RSA parameters for anonymous authentication.
The callback should return <code class="code">GNUTLS_E_SUCCESS</code>  (0) on success.
</p>
<p><strong class="strong">Deprecated:</strong> This function is unnecessary and discouraged on GnuTLS 3.6.0
or later. Since 3.6.0, DH parameters are negotiated
following RFC7919.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fanon_005fset_005fserver_005fdh_005fparams-1"><span>gnutls_anon_set_server_dh_params<a class="copiable-link" href="#gnutls_005fanon_005fset_005fserver_005fdh_005fparams-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fanon_005fset_005fserver_005fdh_005fparams"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fanon_005fset_005fserver_005fdh_005fparams"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_anon_set_server_dh_params</strong> <code class="def-code-arguments">(gnutls_anon_server_credentials_t <var class="var">res</var>, gnutls_dh_params_t <var class="var">dh_params</var>)</code><a class="copiable-link" href="#index-gnutls_005fanon_005fset_005fserver_005fdh_005fparams"> &para;</a></span></dt>
<dd><p><var class="var">res</var>: is a gnutls_anon_server_credentials_t type
</p>
<p><var class="var">dh_params</var>: The Diffie-Hellman parameters.
</p>
<p>This function will set the Diffie-Hellman parameters for an
anonymous server to use.  These parameters will be used in
Anonymous Diffie-Hellman cipher suites.
</p>
<p><strong class="strong">Deprecated:</strong> This function is unnecessary and discouraged on GnuTLS 3.6.0
or later. Since 3.6.0, DH parameters are negotiated
following RFC7919.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fanon_005fset_005fserver_005fknown_005fdh_005fparams-1"><span>gnutls_anon_set_server_known_dh_params<a class="copiable-link" href="#gnutls_005fanon_005fset_005fserver_005fknown_005fdh_005fparams-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fanon_005fset_005fserver_005fknown_005fdh_005fparams"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fanon_005fset_005fserver_005fknown_005fdh_005fparams"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_anon_set_server_known_dh_params</strong> <code class="def-code-arguments">(gnutls_anon_server_credentials_t <var class="var">res</var>, gnutls_sec_param_t <var class="var">sec_param</var>)</code><a class="copiable-link" href="#index-gnutls_005fanon_005fset_005fserver_005fknown_005fdh_005fparams"> &para;</a></span></dt>
<dd><p><var class="var">res</var>: is a gnutls_anon_server_credentials_t type
</p>
<p><var class="var">sec_param</var>: is an option of the <code class="code">gnutls_sec_param_t</code>  enumeration
</p>
<p>This function will set the Diffie-Hellman parameters for an
anonymous server to use.  These parameters will be used in
Anonymous Diffie-Hellman cipher suites and will be selected from
the FFDHE set of RFC7919 according to the security level provided.
</p>
<p><strong class="strong">Deprecated:</strong> This function is unnecessary and discouraged on GnuTLS 3.6.0
or later. Since 3.6.0, DH parameters are negotiated
following RFC7919.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.5.6
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fanon_005fset_005fserver_005fparams_005ffunction-1"><span>gnutls_anon_set_server_params_function<a class="copiable-link" href="#gnutls_005fanon_005fset_005fserver_005fparams_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fanon_005fset_005fserver_005fparams_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fanon_005fset_005fserver_005fparams_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_anon_set_server_params_function</strong> <code class="def-code-arguments">(gnutls_anon_server_credentials_t <var class="var">res</var>, gnutls_params_function * <var class="var">func</var>)</code><a class="copiable-link" href="#index-gnutls_005fanon_005fset_005fserver_005fparams_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">res</var>: is a gnutls_certificate_credentials_t type
</p>
<p><var class="var">func</var>: is the function to be called
</p>
<p>This function will set a callback in order for the server to get
the Diffie-Hellman parameters for anonymous authentication.  The
callback should return <code class="code">GNUTLS_E_SUCCESS</code>  (0) on success.
</p>
<p><strong class="strong">Deprecated:</strong> This function is unnecessary and discouraged on GnuTLS 3.6.0
or later. Since 3.6.0, DH parameters are negotiated
following RFC7919.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fanti_005freplay_005fdeinit-1"><span>gnutls_anti_replay_deinit<a class="copiable-link" href="#gnutls_005fanti_005freplay_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fanti_005freplay_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fanti_005freplay_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_anti_replay_deinit</strong> <code class="def-code-arguments">(gnutls_anti_replay_t <var class="var">anti_replay</var>)</code><a class="copiable-link" href="#index-gnutls_005fanti_005freplay_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">anti_replay</var>: is a <code class="code">gnutls_anti_replay</code>  type
</p>
<p>This function will deinitialize all resources occupied by the given
anti-replay context.
</p>
<p><strong class="strong">Since:</strong> 3.6.5
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fanti_005freplay_005fenable-1"><span>gnutls_anti_replay_enable<a class="copiable-link" href="#gnutls_005fanti_005freplay_005fenable-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fanti_005freplay_005fenable"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fanti_005freplay_005fenable"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_anti_replay_enable</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_anti_replay_t <var class="var">anti_replay</var>)</code><a class="copiable-link" href="#index-gnutls_005fanti_005freplay_005fenable"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">anti_replay</var>: is a <code class="code">gnutls_anti_replay_t</code>  type.
</p>
<p>Request that the server should use anti-replay mechanism.
</p>
<p><strong class="strong">Since:</strong> 3.6.5
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fanti_005freplay_005finit-1"><span>gnutls_anti_replay_init<a class="copiable-link" href="#gnutls_005fanti_005freplay_005finit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fanti_005freplay_005finit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fanti_005freplay_005finit"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_anti_replay_init</strong> <code class="def-code-arguments">(gnutls_anti_replay_t * <var class="var">anti_replay</var>)</code><a class="copiable-link" href="#index-gnutls_005fanti_005freplay_005finit"> &para;</a></span></dt>
<dd><p><var class="var">anti_replay</var>: is a pointer to <code class="code">gnutls_anti_replay_t</code>  type
</p>
<p>This function will allocate and initialize the  <code class="code">anti_replay</code> context
to be usable for detect replay attacks. The context can then be
attached to a  <code class="code">gnutls_session_t</code> with
<code class="code">gnutls_anti_replay_enable()</code> .
</p>
<p><strong class="strong">Returns:</strong> Zero or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 3.6.5
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fanti_005freplay_005fset_005fadd_005ffunction-1"><span>gnutls_anti_replay_set_add_function<a class="copiable-link" href="#gnutls_005fanti_005freplay_005fset_005fadd_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fanti_005freplay_005fset_005fadd_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fanti_005freplay_005fset_005fadd_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_anti_replay_set_add_function</strong> <code class="def-code-arguments">(gnutls_anti_replay_t <var class="var">anti_replay</var>, gnutls_db_add_func <var class="var">add_func</var>)</code><a class="copiable-link" href="#index-gnutls_005fanti_005freplay_005fset_005fadd_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">anti_replay</var>: is a <code class="code">gnutls_anti_replay_t</code>  type.
</p>
<p><var class="var">add_func</var>: is the function.
</p>
<p>Sets the function that will be used to store an entry if it is not
already present in the resumed sessions database.  This function returns 0
if the entry is successfully stored, and a negative error code
otherwise.  In particular, if the entry is found in the database,
it returns <code class="code">GNUTLS_E_DB_ENTRY_EXISTS</code> .
</p>
<p>The arguments to the  <code class="code">add_func</code> are:
- <code class="code">ptr</code> : the pointer set with <code class="code">gnutls_anti_replay_set_ptr()</code> 
- <code class="code">exp_time</code> : the expiration time of the entry
- <code class="code">key</code> : a pointer to the key
- <code class="code">data</code> : a pointer to data to store
</p>
<p>The data set by this function can be examined using
<code class="code">gnutls_db_check_entry_expire_time()</code>  and <code class="code">gnutls_db_check_entry_time()</code> .
</p>
<p><strong class="strong">Since:</strong> 3.6.5
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fanti_005freplay_005fset_005fptr-1"><span>gnutls_anti_replay_set_ptr<a class="copiable-link" href="#gnutls_005fanti_005freplay_005fset_005fptr-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fanti_005freplay_005fset_005fptr"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fanti_005freplay_005fset_005fptr"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_anti_replay_set_ptr</strong> <code class="def-code-arguments">(gnutls_anti_replay_t <var class="var">anti_replay</var>, void * <var class="var">ptr</var>)</code><a class="copiable-link" href="#index-gnutls_005fanti_005freplay_005fset_005fptr"> &para;</a></span></dt>
<dd><p><var class="var">anti_replay</var>: is a <code class="code">gnutls_anti_replay_t</code>  type.
</p>
<p><var class="var">ptr</var>: is the pointer
</p>
<p>Sets the pointer that will be provided to db add function
as the first argument.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fanti_005freplay_005fset_005fwindow-1"><span>gnutls_anti_replay_set_window<a class="copiable-link" href="#gnutls_005fanti_005freplay_005fset_005fwindow-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fanti_005freplay_005fset_005fwindow"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fanti_005freplay_005fset_005fwindow"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_anti_replay_set_window</strong> <code class="def-code-arguments">(gnutls_anti_replay_t <var class="var">anti_replay</var>, unsigned int <var class="var">window</var>)</code><a class="copiable-link" href="#index-gnutls_005fanti_005freplay_005fset_005fwindow"> &para;</a></span></dt>
<dd><p><var class="var">anti_replay</var>: is a <code class="code">gnutls_anti_replay_t</code>  type.
</p>
<p><var class="var">window</var>: is the time window recording ClientHello, in milliseconds
</p>
<p>Sets the time window used for ClientHello recording.  In order to
protect against replay attacks, the server records ClientHello
messages within this time period from the last update, and
considers it a replay when a ClientHello outside of the period; if
a ClientHello arrives within this period, the server checks the
database and detects duplicates.
</p>
<p>For the details of the algorithm, see RFC 8446, section 8.2.
</p>
<p><strong class="strong">Since:</strong> 3.6.5
</p></dd></dl>

<h4 class="subheading" id="gnutls_005faudit_005fcurrent_005fcontext-1"><span>gnutls_audit_current_context<a class="copiable-link" href="#gnutls_005faudit_005fcurrent_005fcontext-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005faudit_005fcurrent_005fcontext"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005faudit_005fcurrent_005fcontext"><span class="category-def">Function: </span><span><code class="def-type">long</code> <strong class="def-name">gnutls_audit_current_context</strong> <code class="def-code-arguments">( <var class="var">void</var>)</code><a class="copiable-link" href="#index-gnutls_005faudit_005fcurrent_005fcontext"> &para;</a></span></dt>
<dd>
<p>Return the current crypto-auditing context from the thread-local
context stack. This is useful for the applications that define
their own probe points for application level protocols.
</p>
<p><strong class="strong">Returns:</strong> an opaque context
</p>
<p><strong class="strong">Since:</strong> 3.8.11
</p></dd></dl>

<h4 class="subheading" id="gnutls_005faudit_005fpop_005fcontext-1"><span>gnutls_audit_pop_context<a class="copiable-link" href="#gnutls_005faudit_005fpop_005fcontext-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005faudit_005fpop_005fcontext"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005faudit_005fpop_005fcontext"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_audit_pop_context</strong> <code class="def-code-arguments">( <var class="var">void</var>)</code><a class="copiable-link" href="#index-gnutls_005faudit_005fpop_005fcontext"> &para;</a></span></dt>
<dd>
<p>Pop the current crypto-auditing context from the thread-local
context stack. This is useful for the applications that define
their own probe points for application level protocols.
</p>
<p><strong class="strong">Since:</strong> 3.8.11
</p></dd></dl>

<h4 class="subheading" id="gnutls_005faudit_005fpush_005fcontext-1"><span>gnutls_audit_push_context<a class="copiable-link" href="#gnutls_005faudit_005fpush_005fcontext-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005faudit_005fpush_005fcontext"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005faudit_005fpush_005fcontext"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_audit_push_context</strong> <code class="def-code-arguments">(long <var class="var">context</var>)</code><a class="copiable-link" href="#index-gnutls_005faudit_005fpush_005fcontext"> &para;</a></span></dt>
<dd><p><var class="var">context</var>: an opaque context
</p>
<p>Push a new crypto-auditing context to the thread-local context
stack. The call must match the following <code class="code">gnutls_audit_pop_context()</code> 
call. This is useful for the applications that define their own
probe points for application level protocols.
</p>
<p><strong class="strong">Since:</strong> 3.8.11
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fauth_005fclient_005fget_005ftype-1"><span>gnutls_auth_client_get_type<a class="copiable-link" href="#gnutls_005fauth_005fclient_005fget_005ftype-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fauth_005fclient_005fget_005ftype"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fauth_005fclient_005fget_005ftype"><span class="category-def">Function: </span><span><code class="def-type">gnutls_credentials_type_t</code> <strong class="def-name">gnutls_auth_client_get_type</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fauth_005fclient_005fget_005ftype"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>Returns the type of credentials that were used for client authentication.
The returned information is to be used to distinguish the function used
to access authentication data.
</p>
<p>Note that on resumed sessions, this function returns the schema
used in the original session authentication.
</p>
<p><strong class="strong">Returns:</strong> The type of credentials for the client authentication
schema, a <code class="code">gnutls_credentials_type_t</code>  type.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fauth_005fget_005ftype-1"><span>gnutls_auth_get_type<a class="copiable-link" href="#gnutls_005fauth_005fget_005ftype-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fauth_005fget_005ftype"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fauth_005fget_005ftype"><span class="category-def">Function: </span><span><code class="def-type">gnutls_credentials_type_t</code> <strong class="def-name">gnutls_auth_get_type</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fauth_005fget_005ftype"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>Returns type of credentials for the current authentication schema.
The returned information is to be used to distinguish the function used
to access authentication data.
</p>
<p>Eg. for CERTIFICATE ciphersuites (key exchange algorithms:
<code class="code">GNUTLS_KX_RSA</code> , <code class="code">GNUTLS_KX_DHE_RSA</code> ), the same function are to be
used to access the authentication data.
</p>
<p>Note that on resumed sessions, this function returns the schema
used in the original session authentication.
</p>
<p><strong class="strong">Returns:</strong> The type of credentials for the current authentication
schema, a <code class="code">gnutls_credentials_type_t</code>  type.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fauth_005fserver_005fget_005ftype-1"><span>gnutls_auth_server_get_type<a class="copiable-link" href="#gnutls_005fauth_005fserver_005fget_005ftype-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fauth_005fserver_005fget_005ftype"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fauth_005fserver_005fget_005ftype"><span class="category-def">Function: </span><span><code class="def-type">gnutls_credentials_type_t</code> <strong class="def-name">gnutls_auth_server_get_type</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fauth_005fserver_005fget_005ftype"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>Returns the type of credentials that were used for server authentication.
The returned information is to be used to distinguish the function used
to access authentication data.
</p>
<p>Note that on resumed sessions, this function returns the schema
used in the original session authentication.
</p>
<p><strong class="strong">Returns:</strong> The type of credentials for the server authentication
schema, a <code class="code">gnutls_credentials_type_t</code>  type.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fbase64_005fdecode2-1"><span>gnutls_base64_decode2<a class="copiable-link" href="#gnutls_005fbase64_005fdecode2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fbase64_005fdecode2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fbase64_005fdecode2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_base64_decode2</strong> <code class="def-code-arguments">(const gnutls_datum_t * <var class="var">base64</var>, gnutls_datum_t * <var class="var">result</var>)</code><a class="copiable-link" href="#index-gnutls_005fbase64_005fdecode2"> &para;</a></span></dt>
<dd><p><var class="var">base64</var>: contains the encoded data
</p>
<p><var class="var">result</var>: the location of decoded data
</p>
<p>This function will decode the given base64 encoded data. The decoded data
will be allocated, and stored into result.
</p>
<p>You should use <code class="code">gnutls_free()</code>  to free the returned data.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise
an error code is returned.
</p>
<p><strong class="strong">Since:</strong> 3.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fbase64_005fencode2-1"><span>gnutls_base64_encode2<a class="copiable-link" href="#gnutls_005fbase64_005fencode2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fbase64_005fencode2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fbase64_005fencode2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_base64_encode2</strong> <code class="def-code-arguments">(const gnutls_datum_t * <var class="var">data</var>, gnutls_datum_t * <var class="var">result</var>)</code><a class="copiable-link" href="#index-gnutls_005fbase64_005fencode2"> &para;</a></span></dt>
<dd><p><var class="var">data</var>: contains the raw data
</p>
<p><var class="var">result</var>: will hold the newly allocated encoded data
</p>
<p>This function will convert the given data to printable data, using
the base64 encoding. This function will allocate the required
memory to hold the encoded data.
</p>
<p>You should use <code class="code">gnutls_free()</code>  to free the returned data.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise
an error code is returned.
</p>
<p><strong class="strong">Since:</strong> 3.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fbuffer_005fappend_005fdata-1"><span>gnutls_buffer_append_data<a class="copiable-link" href="#gnutls_005fbuffer_005fappend_005fdata-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fbuffer_005fappend_005fdata"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fbuffer_005fappend_005fdata"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_buffer_append_data</strong> <code class="def-code-arguments">(gnutls_buffer_t <var class="var">dest</var>, const void * <var class="var">data</var>, size_t <var class="var">data_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fbuffer_005fappend_005fdata"> &para;</a></span></dt>
<dd><p><var class="var">dest</var>: the buffer to append to
</p>
<p><var class="var">data</var>: the data
</p>
<p><var class="var">data_size</var>: the size of  <code class="code">data</code> 
</p>
<p>Appends the provided  <code class="code">data</code> to the destination buffer.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fbye-1"><span>gnutls_bye<a class="copiable-link" href="#gnutls_005fbye-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fbye"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fbye-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_bye</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_close_request_t <var class="var">how</var>)</code><a class="copiable-link" href="#index-gnutls_005fbye-1"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">how</var>: is an integer
</p>
<p>Terminates the current TLS/SSL connection. The connection should
have been initiated using <code class="code">gnutls_handshake()</code> .   <code class="code">how</code> should be one
of <code class="code">GNUTLS_SHUT_RDWR</code> , <code class="code">GNUTLS_SHUT_WR</code> .
</p>
<p>In case of <code class="code">GNUTLS_SHUT_RDWR</code>  the TLS session gets
terminated and further receives and sends will be disallowed.  If
the return value is zero you may continue using the underlying
transport layer. <code class="code">GNUTLS_SHUT_RDWR</code>  sends an alert containing a close
request and waits for the peer to reply with the same message.
</p>
<p>In case of <code class="code">GNUTLS_SHUT_WR</code>  the TLS session gets terminated
and further sends will be disallowed. In order to reuse the
connection you should wait for an EOF from the peer.
<code class="code">GNUTLS_SHUT_WR</code>  sends an alert containing a close request.
</p>
<p>Note that not all implementations will properly terminate a TLS
connection.  Some of them, usually for performance reasons, will
terminate only the underlying transport layer, and thus not
distinguishing between a malicious party prematurely terminating
the connection and normal termination.
</p>
<p>This function may also return <code class="code">GNUTLS_E_AGAIN</code>  or
<code class="code">GNUTLS_E_INTERRUPTED</code> ; cf.  <code class="code">gnutls_record_get_direction()</code> .
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, or an error code, see
function documentation for entire semantics.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005factivation_005ftime_005fpeers-1"><span>gnutls_certificate_activation_time_peers<a class="copiable-link" href="#gnutls_005fcertificate_005factivation_005ftime_005fpeers-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005factivation_005ftime_005fpeers"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005factivation_005ftime_005fpeers"><span class="category-def">Function: </span><span><code class="def-type">time_t</code> <strong class="def-name">gnutls_certificate_activation_time_peers</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005factivation_005ftime_005fpeers"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a gnutls session
</p>
<p>This function will return the peer&rsquo;s certificate activation time.
</p>
<p><strong class="strong">Returns:</strong> (time_t)-1 on error.
</p>
<p><strong class="strong">Deprecated:</strong> <code class="code">gnutls_certificate_verify_peers2()</code>  now verifies activation times.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fallocate_005fcredentials-1"><span>gnutls_certificate_allocate_credentials<a class="copiable-link" href="#gnutls_005fcertificate_005fallocate_005fcredentials-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fallocate_005fcredentials"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fallocate_005fcredentials"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_certificate_allocate_credentials</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t * <var class="var">res</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fallocate_005fcredentials"> &para;</a></span></dt>
<dd><p><var class="var">res</var>: is a pointer to a <code class="code">gnutls_certificate_credentials_t</code>  type.
</p>
<p>Allocate a gnutls_certificate_credentials_t structure.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, or an error code.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fclient_005fget_005frequest_005fstatus-1"><span>gnutls_certificate_client_get_request_status<a class="copiable-link" href="#gnutls_005fcertificate_005fclient_005fget_005frequest_005fstatus-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fclient_005fget_005frequest_005fstatus"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fclient_005fget_005frequest_005fstatus"><span class="category-def">Function: </span><span><code class="def-type">unsigned</code> <strong class="def-name">gnutls_certificate_client_get_request_status</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fclient_005fget_005frequest_005fstatus"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a gnutls session
</p>
<p>Get whether client certificate was requested on the last
handshake or not.
</p>
<p><strong class="strong">Returns:</strong> 0 if the peer (server) did not request client
authentication or 1 otherwise.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fexpiration_005ftime_005fpeers-1"><span>gnutls_certificate_expiration_time_peers<a class="copiable-link" href="#gnutls_005fcertificate_005fexpiration_005ftime_005fpeers-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fexpiration_005ftime_005fpeers"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fexpiration_005ftime_005fpeers"><span class="category-def">Function: </span><span><code class="def-type">time_t</code> <strong class="def-name">gnutls_certificate_expiration_time_peers</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fexpiration_005ftime_005fpeers"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a gnutls session
</p>
<p>This function will return the peer&rsquo;s certificate expiration time.
</p>
<p><strong class="strong">Returns:</strong> (time_t)-1 on error.
</p>
<p><strong class="strong">Deprecated:</strong> <code class="code">gnutls_certificate_verify_peers2()</code>  now verifies expiration times.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005ffree_005fca_005fnames-1"><span>gnutls_certificate_free_ca_names<a class="copiable-link" href="#gnutls_005fcertificate_005ffree_005fca_005fnames-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005ffree_005fca_005fnames"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005ffree_005fca_005fnames"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_certificate_free_ca_names</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">sc</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005ffree_005fca_005fnames"> &para;</a></span></dt>
<dd><p><var class="var">sc</var>: is a <code class="code">gnutls_certificate_credentials_t</code>  type.
</p>
<p>This function will delete all the CA name in the given
credentials. Clients may call this to save some memory since in
client side the CA names are not used. Servers might want to use
this function if a large list of trusted CAs is present and
sending the names of it would just consume bandwidth without providing
information to client.
</p>
<p>CA names are used by servers to advertise the CAs they support to
clients.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005ffree_005fcas-1"><span>gnutls_certificate_free_cas<a class="copiable-link" href="#gnutls_005fcertificate_005ffree_005fcas-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005ffree_005fcas"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005ffree_005fcas"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_certificate_free_cas</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">sc</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005ffree_005fcas"> &para;</a></span></dt>
<dd><p><var class="var">sc</var>: is a <code class="code">gnutls_certificate_credentials_t</code>  type.
</p>
<p>This function was operational on very early versions of gnutls.
Due to internal refactorings and the fact that this was hardly ever
used, it is currently a no-op.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005ffree_005fcredentials-1"><span>gnutls_certificate_free_credentials<a class="copiable-link" href="#gnutls_005fcertificate_005ffree_005fcredentials-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005ffree_005fcredentials"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005ffree_005fcredentials"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_certificate_free_credentials</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">sc</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005ffree_005fcredentials"> &para;</a></span></dt>
<dd><p><var class="var">sc</var>: is a <code class="code">gnutls_certificate_credentials_t</code>  type.
</p>
<p>Free a gnutls_certificate_credentials_t structure.
</p>
<p>This function does not free any temporary parameters associated
with this structure (ie RSA and DH parameters are not freed by this
function).
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005ffree_005fcrls-1"><span>gnutls_certificate_free_crls<a class="copiable-link" href="#gnutls_005fcertificate_005ffree_005fcrls-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005ffree_005fcrls"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005ffree_005fcrls"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_certificate_free_crls</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">sc</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005ffree_005fcrls"> &para;</a></span></dt>
<dd><p><var class="var">sc</var>: is a <code class="code">gnutls_certificate_credentials_t</code>  type.
</p>
<p>This function will delete all the CRLs associated
with the given credentials.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005ffree_005fkeys-1"><span>gnutls_certificate_free_keys<a class="copiable-link" href="#gnutls_005fcertificate_005ffree_005fkeys-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005ffree_005fkeys"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005ffree_005fkeys"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_certificate_free_keys</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">sc</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005ffree_005fkeys"> &para;</a></span></dt>
<dd><p><var class="var">sc</var>: is a <code class="code">gnutls_certificate_credentials_t</code>  type.
</p>
<p>This function will delete all the keys and the certificates associated
with the given credentials. This function must not be called when a
TLS negotiation that uses the credentials is in progress.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fget_005fcrt_005fraw-1"><span>gnutls_certificate_get_crt_raw<a class="copiable-link" href="#gnutls_005fcertificate_005fget_005fcrt_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fget_005fcrt_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fget_005fcrt_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_certificate_get_crt_raw</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">sc</var>, unsigned <var class="var">idx1</var>, unsigned <var class="var">idx2</var>, gnutls_datum_t * <var class="var">cert</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fget_005fcrt_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">sc</var>: is a <code class="code">gnutls_certificate_credentials_t</code>  type.
</p>
<p><var class="var">idx1</var>: the index of the certificate chain if multiple are present
</p>
<p><var class="var">idx2</var>: the index of the certificate in the chain. Zero gives the server&rsquo;s certificate.
</p>
<p><var class="var">cert</var>: Will hold the DER encoded certificate.
</p>
<p>This function will return the DER encoded certificate of the
server or any other certificate on its certificate chain (based on  <code class="code">idx2</code> ).
The returned data should be treated as constant and only accessible during the lifetime
of  <code class="code">sc</code> . The  <code class="code">idx1</code> matches the value <code class="code">gnutls_certificate_set_x509_key()</code>  and friends
functions.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value. In case the indexes are out of bounds <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> 
is returned.
</p>
<p><strong class="strong">Since:</strong> 3.2.5
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fget_005fissuer-1"><span>gnutls_certificate_get_issuer<a class="copiable-link" href="#gnutls_005fcertificate_005fget_005fissuer-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fget_005fissuer"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fget_005fissuer"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_certificate_get_issuer</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">sc</var>, gnutls_x509_crt_t <var class="var">cert</var>, gnutls_x509_crt_t * <var class="var">issuer</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fget_005fissuer"> &para;</a></span></dt>
<dd><p><var class="var">sc</var>: is a <code class="code">gnutls_certificate_credentials_t</code>  type.
</p>
<p><var class="var">cert</var>: is the certificate to find issuer for
</p>
<p><var class="var">issuer</var>: Will hold the issuer if any. Should be treated as constant.
</p>
<p><var class="var">flags</var>: Use zero or <code class="code">GNUTLS_TL_GET_COPY</code> 
</p>
<p>This function will return the issuer of a given certificate.
If the flag <code class="code">GNUTLS_TL_GET_COPY</code>  is specified a copy of the issuer
will be returned which must be freed using <code class="code">gnutls_x509_crt_deinit()</code> .
In that case the provided  <code class="code">issuer</code> must not be initialized.
</p>
<p>As with <code class="code">gnutls_x509_trust_list_get_issuer()</code>  this function requires
the <code class="code">GNUTLS_TL_GET_COPY</code>  flag in order to operate with PKCS<code class="code">11</code>  trust
lists in a thread-safe way.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fget_005focsp_005fexpiration-1"><span>gnutls_certificate_get_ocsp_expiration<a class="copiable-link" href="#gnutls_005fcertificate_005fget_005focsp_005fexpiration-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fget_005focsp_005fexpiration"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fget_005focsp_005fexpiration-1"><span class="category-def">Function: </span><span><code class="def-type">time_t</code> <strong class="def-name">gnutls_certificate_get_ocsp_expiration</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">sc</var>, unsigned <var class="var">idx</var>, int <var class="var">oidx</var>, unsigned <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fget_005focsp_005fexpiration-1"> &para;</a></span></dt>
<dd><p><var class="var">sc</var>: is a credentials structure.
</p>
<p><var class="var">idx</var>: is a certificate chain index as returned by <code class="code">gnutls_certificate_set_key()</code>  and friends
</p>
<p><var class="var">oidx</var>: is an OCSP response index
</p>
<p><var class="var">flags</var>: should be zero
</p>
<p>This function returns the validity of the loaded OCSP responses,
to provide information on when to reload/refresh them.
</p>
<p>Note that the credentials structure should be read-only when in
use, thus when reloading, either the credentials structure must not
be in use by any sessions, or a new credentials structure should be
allocated for new sessions.
</p>
<p>When  <code class="code">oidx</code> is (-1) then the minimum refresh time for all responses
is returned. Otherwise the index specifies the response corresponding
to the  <code class="code">odix</code> certificate in the certificate chain.
</p>
<p><strong class="strong">Returns:</strong> On success, the expiration time of the OCSP response. Otherwise
(time_t)(-1) on error, or (time_t)-2 on out of bounds.
</p>
<p><strong class="strong">Since:</strong> 3.6.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fget_005fours-1"><span>gnutls_certificate_get_ours<a class="copiable-link" href="#gnutls_005fcertificate_005fget_005fours-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fget_005fours"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fget_005fours"><span class="category-def">Function: </span><span><code class="def-type">const gnutls_datum_t *</code> <strong class="def-name">gnutls_certificate_get_ours</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fget_005fours"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a gnutls session
</p>
<p>Gets the certificate as sent to the peer in the last handshake.
The certificate is in raw (DER) format.  No certificate
list is being returned. Only the first certificate.
</p>
<p>This function returns the certificate that was sent in the current
handshake. In subsequent resumed sessions this function will return
<code class="code">NULL</code> . That differs from <code class="code">gnutls_certificate_get_peers()</code>  which always
returns the peer&rsquo;s certificate used in the original session.
</p>
<p><strong class="strong">Returns:</strong> a pointer to a <code class="code">gnutls_datum_t</code>  containing our
certificate, or <code class="code">NULL</code>  in case of an error or if no certificate
was used.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fget_005fpeers-1"><span>gnutls_certificate_get_peers<a class="copiable-link" href="#gnutls_005fcertificate_005fget_005fpeers-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fget_005fpeers"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fget_005fpeers"><span class="category-def">Function: </span><span><code class="def-type">const gnutls_datum_t *</code> <strong class="def-name">gnutls_certificate_get_peers</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, unsigned int * <var class="var">list_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fget_005fpeers"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a gnutls session
</p>
<p><var class="var">list_size</var>: is the length of the certificate list (may be <code class="code">NULL</code> )
</p>
<p>Get the peer&rsquo;s raw certificate (chain) as sent by the peer.  These
certificates are in raw format (DER encoded for X.509).  In case of
a X.509 then a certificate list may be present.  The list
is provided as sent by the server; the server must send as first
certificate in the list its own certificate, following the
issuer&rsquo;s certificate, then the issuer&rsquo;s issuer etc. However, there
are servers which violate this principle and thus on certain
occasions this may be an unsorted list.
</p>
<p>In resumed sessions, this function will return the peer&rsquo;s certificate
list as used in the first/original session.
</p>
<p><strong class="strong">Returns:</strong> a pointer to a <code class="code">gnutls_datum_t</code>  containing the peer&rsquo;s
certificates, or <code class="code">NULL</code>  in case of an error or if no certificate
was used.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fget_005fpeers_005fsubkey_005fid-1"><span>gnutls_certificate_get_peers_subkey_id<a class="copiable-link" href="#gnutls_005fcertificate_005fget_005fpeers_005fsubkey_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fget_005fpeers_005fsubkey_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fget_005fpeers_005fsubkey_005fid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_certificate_get_peers_subkey_id</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_datum_t * <var class="var">id</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fget_005fpeers_005fsubkey_005fid"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a gnutls session
</p>
<p><var class="var">id</var>: will contain the ID
</p>
<p>This function is no-op.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_UNIMPLEMENTED_FEATURE</code> .
</p>
<p><strong class="strong">Since:</strong> 3.1.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fget_005fverify_005fflags-1"><span>gnutls_certificate_get_verify_flags<a class="copiable-link" href="#gnutls_005fcertificate_005fget_005fverify_005fflags-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fget_005fverify_005fflags"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fget_005fverify_005fflags"><span class="category-def">Function: </span><span><code class="def-type">unsigned int</code> <strong class="def-name">gnutls_certificate_get_verify_flags</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">res</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fget_005fverify_005fflags"> &para;</a></span></dt>
<dd><p><var class="var">res</var>: is a gnutls_certificate_credentials_t type
</p>
<p>Returns the verification flags set with
<code class="code">gnutls_certificate_set_verify_flags()</code> .
</p>
<p><strong class="strong">Returns:</strong> The certificate verification flags used by  <code class="code">res</code> .
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fget_005fx509_005fcrt-1"><span>gnutls_certificate_get_x509_crt<a class="copiable-link" href="#gnutls_005fcertificate_005fget_005fx509_005fcrt-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fget_005fx509_005fcrt"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fget_005fx509_005fcrt"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_certificate_get_x509_crt</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">res</var>, unsigned <var class="var">index</var>, gnutls_x509_crt_t ** <var class="var">crt_list</var>, unsigned * <var class="var">crt_list_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fget_005fx509_005fcrt"> &para;</a></span></dt>
<dd><p><var class="var">res</var>: is a <code class="code">gnutls_certificate_credentials_t</code>  type.
</p>
<p><var class="var">index</var>: The index of the certificate list to obtain.
</p>
<p><var class="var">crt_list</var>: Where to store the certificate list.
</p>
<p><var class="var">crt_list_size</var>: Will hold the number of certificates.
</p>
<p>Obtains a X.509 certificate list that has been stored in  <code class="code">res</code> with one of
<code class="code">gnutls_certificate_set_x509_key()</code> , <code class="code">gnutls_certificate_set_key()</code> ,
<code class="code">gnutls_certificate_set_x509_key_file()</code> ,
<code class="code">gnutls_certificate_set_x509_key_file2()</code> ,
<code class="code">gnutls_certificate_set_x509_key_mem()</code> , or
<code class="code">gnutls_certificate_set_x509_key_mem2()</code> . Each certificate in the returned
certificate list must be deallocated with <code class="code">gnutls_x509_crt_deinit()</code> , and the
list itself must be freed with <code class="code">gnutls_free()</code> .
</p>
<p>The  <code class="code">index</code> matches the return value of <code class="code">gnutls_certificate_set_x509_key()</code>  and friends
functions, when the <code class="code">GNUTLS_CERTIFICATE_API_V2</code>  flag is set.
</p>
<p>If there is no certificate with the given index,
<code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  is returned. If the certificate
with the given index is not a X.509 certificate, <code class="code">GNUTLS_E_INVALID_REQUEST</code> 
is returned. The returned certificates must be deinitialized after
use, and the  <code class="code">crt_list</code> pointer must be freed using <code class="code">gnutls_free()</code> .
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  (0) on success, or a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fget_005fx509_005fkey-1"><span>gnutls_certificate_get_x509_key<a class="copiable-link" href="#gnutls_005fcertificate_005fget_005fx509_005fkey-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fget_005fx509_005fkey"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fget_005fx509_005fkey"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_certificate_get_x509_key</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">res</var>, unsigned <var class="var">index</var>, gnutls_x509_privkey_t * <var class="var">key</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fget_005fx509_005fkey"> &para;</a></span></dt>
<dd><p><var class="var">res</var>: is a <code class="code">gnutls_certificate_credentials_t</code>  type.
</p>
<p><var class="var">index</var>: The index of the key to obtain.
</p>
<p><var class="var">key</var>: Location to store the key.
</p>
<p>Obtains a X.509 private key that has been stored in  <code class="code">res</code> with one of
<code class="code">gnutls_certificate_set_x509_key()</code> , <code class="code">gnutls_certificate_set_key()</code> ,
<code class="code">gnutls_certificate_set_x509_key_file()</code> ,
<code class="code">gnutls_certificate_set_x509_key_file2()</code> ,
<code class="code">gnutls_certificate_set_x509_key_mem()</code> , or
<code class="code">gnutls_certificate_set_x509_key_mem2()</code> . The returned key must be deallocated
with <code class="code">gnutls_x509_privkey_deinit()</code>  when no longer needed.
</p>
<p>The  <code class="code">index</code> matches the return value of <code class="code">gnutls_certificate_set_x509_key()</code>  and friends
functions, when the <code class="code">GNUTLS_CERTIFICATE_API_V2</code>  flag is set.
</p>
<p>If there is no key with the given index,
<code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  is returned. If the key with the
given index is not a X.509 key, <code class="code">GNUTLS_E_INVALID_REQUEST</code>  is returned.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  (0) on success, or a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fsend_005fx509_005frdn_005fsequence-1"><span>gnutls_certificate_send_x509_rdn_sequence<a class="copiable-link" href="#gnutls_005fcertificate_005fsend_005fx509_005frdn_005fsequence-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fsend_005fx509_005frdn_005fsequence"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fsend_005fx509_005frdn_005fsequence-1"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_certificate_send_x509_rdn_sequence</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, int <var class="var">status</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fsend_005fx509_005frdn_005fsequence-1"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">status</var>: is 0 or 1
</p>
<p>If status is non zero, this function will order gnutls not to send
the rdnSequence in the certificate request message. That is the
server will not advertise its trusted CAs to the peer. If status
is zero then the default behaviour will take effect, which is to
advertise the server&rsquo;s trusted CAs.
</p>
<p>This function has no effect in clients, and in authentication
methods other than certificate with X.509 certificates.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fserver_005fset_005frequest-1"><span>gnutls_certificate_server_set_request<a class="copiable-link" href="#gnutls_005fcertificate_005fserver_005fset_005frequest-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fserver_005fset_005frequest"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fserver_005fset_005frequest-1"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_certificate_server_set_request</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_certificate_request_t <var class="var">req</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fserver_005fset_005frequest-1"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">req</var>: is one of GNUTLS_CERT_REQUEST, GNUTLS_CERT_REQUIRE, GNUTLS_CERT_IGNORE
</p>
<p>This function specifies if we (in case of a server) are going to
send a certificate request message to the client. If  <code class="code">req</code> is
GNUTLS_CERT_REQUIRE then the server will return the <code class="code">GNUTLS_E_NO_CERTIFICATE_FOUND</code> 
error if the peer does not provide a certificate. If you do not call this
function then the client will not be asked to send a certificate. Invoking
the function with  <code class="code">req</code> GNUTLS_CERT_IGNORE has the same effect.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fset_005fdh_005fparams-1"><span>gnutls_certificate_set_dh_params<a class="copiable-link" href="#gnutls_005fcertificate_005fset_005fdh_005fparams-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fset_005fdh_005fparams"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fset_005fdh_005fparams"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_certificate_set_dh_params</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">res</var>, gnutls_dh_params_t <var class="var">dh_params</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fset_005fdh_005fparams"> &para;</a></span></dt>
<dd><p><var class="var">res</var>: is a gnutls_certificate_credentials_t type
</p>
<p><var class="var">dh_params</var>: the Diffie-Hellman parameters.
</p>
<p>This function will set the Diffie-Hellman parameters for a
certificate server to use. These parameters will be used in
Ephemeral Diffie-Hellman cipher suites.  Note that only a pointer
to the parameters are stored in the certificate handle, so you
must not deallocate the parameters before the certificate is deallocated.
</p>
<p><strong class="strong">Deprecated:</strong> This function is unnecessary and discouraged on GnuTLS 3.6.0
or later. Since 3.6.0, DH parameters are negotiated
following RFC7919.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fset_005fflags-1"><span>gnutls_certificate_set_flags<a class="copiable-link" href="#gnutls_005fcertificate_005fset_005fflags-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fset_005fflags"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fset_005fflags"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_certificate_set_flags</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">res</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fset_005fflags"> &para;</a></span></dt>
<dd><p><var class="var">res</var>: is a gnutls_certificate_credentials_t type
</p>
<p><var class="var">flags</var>: are the flags of <code class="code">gnutls_certificate_flags</code>  type
</p>
<p>This function will set flags to tweak the operation of
the credentials structure. See the <code class="code">gnutls_certificate_flags</code>  enumerations
for more information on the available flags.
</p>
<p><strong class="strong">Since:</strong> 3.4.7
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fset_005fknown_005fdh_005fparams-1"><span>gnutls_certificate_set_known_dh_params<a class="copiable-link" href="#gnutls_005fcertificate_005fset_005fknown_005fdh_005fparams-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fset_005fknown_005fdh_005fparams"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fset_005fknown_005fdh_005fparams"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_certificate_set_known_dh_params</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">res</var>, gnutls_sec_param_t <var class="var">sec_param</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fset_005fknown_005fdh_005fparams"> &para;</a></span></dt>
<dd><p><var class="var">res</var>: is a gnutls_certificate_credentials_t type
</p>
<p><var class="var">sec_param</var>: is an option of the <code class="code">gnutls_sec_param_t</code>  enumeration
</p>
<p>This function will set the Diffie-Hellman parameters for a
certificate server to use. These parameters will be used in
Ephemeral Diffie-Hellman cipher suites and will be selected from
the FFDHE set of RFC7919 according to the security level provided.
</p>
<p><strong class="strong">Deprecated:</strong> This function is unnecessary and discouraged on GnuTLS 3.6.0
or later. Since 3.6.0, DH parameters are negotiated
following RFC7919.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.5.6
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fset_005focsp_005fstatus_005frequest_005ffile-1"><span>gnutls_certificate_set_ocsp_status_request_file<a class="copiable-link" href="#gnutls_005fcertificate_005fset_005focsp_005fstatus_005frequest_005ffile-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fset_005focsp_005fstatus_005frequest_005ffile"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fset_005focsp_005fstatus_005frequest_005ffile"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_certificate_set_ocsp_status_request_file</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">sc</var>, const char * <var class="var">response_file</var>, unsigned <var class="var">idx</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fset_005focsp_005fstatus_005frequest_005ffile"> &para;</a></span></dt>
<dd><p><var class="var">sc</var>: is a credentials structure.
</p>
<p><var class="var">response_file</var>: a filename of the OCSP response
</p>
<p><var class="var">idx</var>: is a certificate index as returned by <code class="code">gnutls_certificate_set_key()</code>  and friends
</p>
<p>This function loads the provided OCSP response. It will be
sent to the client if requests an OCSP certificate status for
the certificate chain specified by  <code class="code">idx</code> .
</p>
<p><strong class="strong">Note:</strong> the ability to set multiple OCSP responses per credential
structure via the index  <code class="code">idx</code> was added in version 3.5.6. To keep
backwards compatibility, it requires using <code class="code">gnutls_certificate_set_flags()</code> 
with the <code class="code">GNUTLS_CERTIFICATE_API_V2</code>  flag to make the set certificate
functions return an index usable by this function.
</p>
<p>This function can be called multiple times since GnuTLS 3.6.3
when multiple responses which apply to the chain are available.
If the response provided does not match any certificates present
in the chain, the code <code class="code">GNUTLS_E_OCSP_MISMATCH_WITH_CERTS</code>  is returned.
To revert to the previous behavior set the flag <code class="code">GNUTLS_CERTIFICATE_SKIP_OCSP_RESPONSE_CHECK</code> 
in the certificate credentials structure. In that case, only the
end-certificate&rsquo;s OCSP response can be set.
If the response is already expired at the time of loading the code
<code class="code">GNUTLS_E_EXPIRED</code>  is returned.
</p>
<p>To revert to the previous behavior of this function which does not return
any errors, set the flag <code class="code">GNUTLS_CERTIFICATE_SKIP_OCSP_RESPONSE_CHECK</code> 
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned.
</p>
<p><strong class="strong">Since:</strong> 3.1.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fset_005focsp_005fstatus_005frequest_005ffile2-1"><span>gnutls_certificate_set_ocsp_status_request_file2<a class="copiable-link" href="#gnutls_005fcertificate_005fset_005focsp_005fstatus_005frequest_005ffile2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fset_005focsp_005fstatus_005frequest_005ffile2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fset_005focsp_005fstatus_005frequest_005ffile2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_certificate_set_ocsp_status_request_file2</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">sc</var>, const char * <var class="var">response_file</var>, unsigned <var class="var">idx</var>, gnutls_x509_crt_fmt_t <var class="var">fmt</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fset_005focsp_005fstatus_005frequest_005ffile2"> &para;</a></span></dt>
<dd><p><var class="var">sc</var>: is a credentials structure.
</p>
<p><var class="var">response_file</var>: a filename of the OCSP response
</p>
<p><var class="var">idx</var>: is a certificate index as returned by <code class="code">gnutls_certificate_set_key()</code>  and friends
</p>
<p><var class="var">fmt</var>: is PEM or DER
</p>
<p>This function loads the OCSP responses to be sent to the
peer for the certificate chain specified by  <code class="code">idx</code> . When  <code class="code">fmt</code> is
set to PEM, multiple responses can be loaded.
</p>
<p>This function must be called after setting any certificates, and
cannot be used for certificates that are provided via a callback &ndash;
that is when <code class="code">gnutls_certificate_set_retrieve_function()</code>  is used. In
that case consider using <code class="code">gnutls_certificate_set_retrieve_function3()</code> .
</p>
<p>This function can be called multiple times when multiple responses
applicable to the certificate chain are available.
If the response provided does not match any certificates present
in the chain, the code <code class="code">GNUTLS_E_OCSP_MISMATCH_WITH_CERTS</code>  is returned.
If the response is already expired at the time of loading the code
<code class="code">GNUTLS_E_EXPIRED</code>  is returned.
</p>
<p><strong class="strong">Returns:</strong> On success, the number of loaded responses is returned,
otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.1.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fset_005focsp_005fstatus_005frequest_005ffunction-1"><span>gnutls_certificate_set_ocsp_status_request_function<a class="copiable-link" href="#gnutls_005fcertificate_005fset_005focsp_005fstatus_005frequest_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fset_005focsp_005fstatus_005frequest_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fset_005focsp_005fstatus_005frequest_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_certificate_set_ocsp_status_request_function</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">sc</var>, gnutls_status_request_ocsp_func <var class="var">ocsp_func</var>, void * <var class="var">ptr</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fset_005focsp_005fstatus_005frequest_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">sc</var>: is a <code class="code">gnutls_certificate_credentials_t</code>  type.
</p>
<p><var class="var">ocsp_func</var>: function pointer to OCSP status request callback.
</p>
<p><var class="var">ptr</var>: opaque pointer passed to callback function
</p>
<p>This function is to be used by server to register a callback to
handle OCSP status requests from the client.  The callback will be
invoked if the client supplied a status-request OCSP extension.
The callback function prototype is:
</p>
<p>typedef int (*gnutls_status_request_ocsp_func)
(gnutls_session_t session, void *ptr, gnutls_datum_t *ocsp_response);
</p>
<p>The callback will be invoked if the client requests an OCSP certificate
status.  The callback may return <code class="code">GNUTLS_E_NO_CERTIFICATE_STATUS</code> , if
there is no recent OCSP response. If the callback returns <code class="code">GNUTLS_E_SUCCESS</code> ,
it is expected to have the  <code class="code">ocsp_response</code> field set with a valid (DER-encoded)
OCSP response. The response must be a value allocated using <code class="code">gnutls_malloc()</code> ,
and will be deinitialized by the caller.
</p>
<p>It is possible to set a specific callback for each provided certificate
using <code class="code">gnutls_certificate_set_ocsp_status_request_function2()</code> .
</p>
<p><strong class="strong">Since:</strong> 3.1.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fset_005focsp_005fstatus_005frequest_005ffunction2-1"><span>gnutls_certificate_set_ocsp_status_request_function2<a class="copiable-link" href="#gnutls_005fcertificate_005fset_005focsp_005fstatus_005frequest_005ffunction2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fset_005focsp_005fstatus_005frequest_005ffunction2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fset_005focsp_005fstatus_005frequest_005ffunction2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_certificate_set_ocsp_status_request_function2</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">sc</var>, unsigned <var class="var">idx</var>, gnutls_status_request_ocsp_func <var class="var">ocsp_func</var>, void * <var class="var">ptr</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fset_005focsp_005fstatus_005frequest_005ffunction2"> &para;</a></span></dt>
<dd><p><var class="var">sc</var>: is a <code class="code">gnutls_certificate_credentials_t</code>  type.
</p>
<p><var class="var">idx</var>: is a certificate index as returned by <code class="code">gnutls_certificate_set_key()</code>  and friends
</p>
<p><var class="var">ocsp_func</var>: function pointer to OCSP status request callback.
</p>
<p><var class="var">ptr</var>: opaque pointer passed to callback function
</p>
<p>This function is to be used by server to register a callback to
provide OCSP status requests that correspond to the indexed certificate chain
from the client.  The callback will be invoked if the client supplied a
status-request OCSP extension.
</p>
<p>The callback function prototype is:
</p>
<p>typedef int (*gnutls_status_request_ocsp_func)
(gnutls_session_t session, void *ptr, gnutls_datum_t *ocsp_response);
</p>
<p>The callback will be invoked if the client requests an OCSP certificate
status.  The callback may return <code class="code">GNUTLS_E_NO_CERTIFICATE_STATUS</code> , if
there is no recent OCSP response. If the callback returns <code class="code">GNUTLS_E_SUCCESS</code> ,
it is expected to have the  <code class="code">ocsp_response</code> field set with a valid (DER-encoded)
OCSP response. The response must be a value allocated using <code class="code">gnutls_malloc()</code> ,
and will be deinitialized by the caller.
</p>
<p><strong class="strong">Note:</strong> the ability to set multiple OCSP responses per credential
structure via the index  <code class="code">idx</code> was added in version 3.5.6. To keep
backwards compatibility, it requires using <code class="code">gnutls_certificate_set_flags()</code> 
with the <code class="code">GNUTLS_CERTIFICATE_API_V2</code>  flag to make the set certificate
functions return an index usable by this function.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned.
</p>
<p><strong class="strong">Since:</strong> 3.5.5
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fset_005focsp_005fstatus_005frequest_005fmem-1"><span>gnutls_certificate_set_ocsp_status_request_mem<a class="copiable-link" href="#gnutls_005fcertificate_005fset_005focsp_005fstatus_005frequest_005fmem-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fset_005focsp_005fstatus_005frequest_005fmem"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fset_005focsp_005fstatus_005frequest_005fmem"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_certificate_set_ocsp_status_request_mem</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">sc</var>, const gnutls_datum_t * <var class="var">resp_data</var>, unsigned <var class="var">idx</var>, gnutls_x509_crt_fmt_t <var class="var">fmt</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fset_005focsp_005fstatus_005frequest_005fmem"> &para;</a></span></dt>
<dd><p><var class="var">sc</var>: is a credentials structure.
</p>
<p><var class="var">resp_data</var>: a memory buffer holding an OCSP response
</p>
<p><var class="var">idx</var>: is a certificate index as returned by <code class="code">gnutls_certificate_set_key()</code>  and friends
</p>
<p><var class="var">fmt</var>: is PEM or DER
</p>
<p>This function sets the OCSP responses to be sent to the
peer for the certificate chain specified by  <code class="code">idx</code> . When  <code class="code">fmt</code> is set
to PEM, multiple responses can be loaded.
</p>
<p><strong class="strong">Note:</strong> the ability to set multiple OCSP responses per credential
structure via the index  <code class="code">idx</code> was added in version 3.5.6. To keep
backwards compatibility, it requires using <code class="code">gnutls_certificate_set_flags()</code> 
with the <code class="code">GNUTLS_CERTIFICATE_API_V2</code>  flag to make the set certificate
functions return an index usable by this function.
</p>
<p>This function must be called after setting any certificates, and
cannot be used for certificates that are provided via a callback &ndash;
that is when <code class="code">gnutls_certificate_set_retrieve_function()</code>  is used.
</p>
<p>This function can be called multiple times when multiple responses which
apply to the certificate chain are available.
If the response provided does not match any certificates present
in the chain, the code <code class="code">GNUTLS_E_OCSP_MISMATCH_WITH_CERTS</code>  is returned.
If the response is already expired at the time of loading the code
<code class="code">GNUTLS_E_EXPIRED</code>  is returned.
</p>
<p><strong class="strong">Returns:</strong> On success, the number of loaded responses is returned,
otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.6.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fset_005fparams_005ffunction-1"><span>gnutls_certificate_set_params_function<a class="copiable-link" href="#gnutls_005fcertificate_005fset_005fparams_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fset_005fparams_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fset_005fparams_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_certificate_set_params_function</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">res</var>, gnutls_params_function * <var class="var">func</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fset_005fparams_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">res</var>: is a gnutls_certificate_credentials_t type
</p>
<p><var class="var">func</var>: is the function to be called
</p>
<p>This function will set a callback in order for the server to get
the Diffie-Hellman or RSA parameters for certificate
authentication.  The callback should return <code class="code">GNUTLS_E_SUCCESS</code>  (0) on success.
</p>
<p><strong class="strong">Deprecated:</strong> This function is unnecessary and discouraged on GnuTLS 3.6.0
or later. Since 3.6.0, DH parameters are negotiated
following RFC7919.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fset_005fpin_005ffunction-1"><span>gnutls_certificate_set_pin_function<a class="copiable-link" href="#gnutls_005fcertificate_005fset_005fpin_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fset_005fpin_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fset_005fpin_005ffunction-1"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_certificate_set_pin_function</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">cred</var>, gnutls_pin_callback_t <var class="var">fn</var>, void * <var class="var">userdata</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fset_005fpin_005ffunction-1"> &para;</a></span></dt>
<dd><p><var class="var">cred</var>: is a <code class="code">gnutls_certificate_credentials_t</code>  type.
</p>
<p><var class="var">fn</var>: A PIN callback
</p>
<p><var class="var">userdata</var>: Data to be passed in the callback
</p>
<p>This function will set a callback function to be used when
required to access a protected object. This function overrides any other
global PIN functions.
</p>
<p>Note that this function must be called right after initialization
to have effect.
</p>
<p><strong class="strong">Since:</strong> 3.1.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fset_005frawpk_005fkey_005ffile-1"><span>gnutls_certificate_set_rawpk_key_file<a class="copiable-link" href="#gnutls_005fcertificate_005fset_005frawpk_005fkey_005ffile-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fset_005frawpk_005fkey_005ffile"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fset_005frawpk_005fkey_005ffile"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_certificate_set_rawpk_key_file</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">cred</var>, const char * <var class="var">rawpkfile</var>, const char * <var class="var">privkeyfile</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, const char * <var class="var">pass</var>, unsigned int <var class="var">key_usage</var>, const char ** <var class="var">names</var>, unsigned int <var class="var">names_length</var>, unsigned int <var class="var">privkey_flags</var>, unsigned int <var class="var">pkcs11_flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fset_005frawpk_005fkey_005ffile"> &para;</a></span></dt>
<dd><p><var class="var">cred</var>: is a <code class="code">gnutls_certificate_credentials_t</code>  type.
</p>
<p><var class="var">rawpkfile</var>: contains a raw public key in
PKIX.SubjectPublicKeyInfo format.
</p>
<p><var class="var">privkeyfile</var>: contains a file path to a private key.
</p>
<p><var class="var">format</var>: encoding of the keys. DER or PEM.
</p>
<p><var class="var">pass</var>: an optional password to unlock the private key privkeyfile.
</p>
<p><var class="var">key_usage</var>: an ORed sequence of <code class="code">GNUTLS_KEY_</code> * flags.
</p>
<p><var class="var">names</var>: is an array of DNS names belonging to the public-key (NULL if none).
</p>
<p><var class="var">names_length</var>: holds the length of the names list.
</p>
<p><var class="var">privkey_flags</var>: an ORed sequence of <code class="code">gnutls_pkcs_encrypt_flags_t</code> .
These apply to the private key pkey.
</p>
<p><var class="var">pkcs11_flags</var>: one of gnutls_pkcs11_obj_flags. These apply to URLs.
</p>
<p>This function sets a public/private keypair read from file in the
<code class="code">gnutls_certificate_credentials_t</code>  type to be used for authentication
and/or encryption.  <code class="code">spki</code> and  <code class="code">privkey</code> should match otherwise set
signatures cannot be validated. In case of no match this function
returns <code class="code">GNUTLS_E_CERTIFICATE_KEY_MISMATCH</code> . This function should
be called once for the client because there is currently no mechanism
to determine which raw public-key to select for the peer when there
are multiple present. Multiple raw public keys for the server can be
distinghuished by setting the  <code class="code">names</code> .
</p>
<p>Note here that  <code class="code">spki</code> is a raw public-key as defined
in RFC7250. It means that there is no surrounding certificate that
holds the public key and that there is therefore no direct mechanism
to prove the authenticity of this key. The keypair can be used during
a TLS handshake but its authenticity should be established via a
different mechanism (e.g. TOFU or known fingerprint).
</p>
<p>The supported formats are basic unencrypted key, PKCS8, PKCS12,
and the openssl format and will be autodetected.
</p>
<p>If the raw public-key and the private key are given in PEM encoding
then the strings that hold their values must be null terminated.
</p>
<p>Key usage (as defined by X.509 extension (2.5.29.15)) can be explicitly
set because there is no certificate structure around the key to define
this value. See for more info <code class="code">gnutls_x509_crt_get_key_usage()</code> .
</p>
<p>Note that, this function by default returns zero on success and a
negative value on error. Since 3.5.6, when the flag <code class="code">GNUTLS_CERTIFICATE_API_V2</code> 
is set using <code class="code">gnutls_certificate_set_flags()</code>  it returns an index
(greater or equal to zero). That index can be used in other functions
to refer to the added key-pair.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, in case the
key pair does not match <code class="code">GNUTLS_E_CERTIFICATE_KEY_MISMATCH</code>  is returned,
in other erroneous cases a different negative error code is returned.
</p>
<p><strong class="strong">Since:</strong> 3.6.6
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fset_005frawpk_005fkey_005fmem-1"><span>gnutls_certificate_set_rawpk_key_mem<a class="copiable-link" href="#gnutls_005fcertificate_005fset_005frawpk_005fkey_005fmem-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fset_005frawpk_005fkey_005fmem"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fset_005frawpk_005fkey_005fmem"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_certificate_set_rawpk_key_mem</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">cred</var>, const gnutls_datum_t * <var class="var">spki</var>, const gnutls_datum_t * <var class="var">pkey</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, const char * <var class="var">pass</var>, unsigned int <var class="var">key_usage</var>, const char ** <var class="var">names</var>, unsigned int <var class="var">names_length</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fset_005frawpk_005fkey_005fmem"> &para;</a></span></dt>
<dd><p><var class="var">cred</var>: is a <code class="code">gnutls_certificate_credentials_t</code>  type.
</p>
<p><var class="var">spki</var>: contains a raw public key in
PKIX.SubjectPublicKeyInfo format.
</p>
<p><var class="var">pkey</var>: contains a raw private key.
</p>
<p><var class="var">format</var>: encoding of the keys. DER or PEM.
</p>
<p><var class="var">pass</var>: an optional password to unlock the private key pkey.
</p>
<p><var class="var">key_usage</var>: An ORed sequence of <code class="code">GNUTLS_KEY_</code> * flags.
</p>
<p><var class="var">names</var>: is an array of DNS names belonging to the public-key (NULL if none).
</p>
<p><var class="var">names_length</var>: holds the length of the names list.
</p>
<p><var class="var">flags</var>: an ORed sequence of <code class="code">gnutls_pkcs_encrypt_flags_t</code> .
These apply to the private key pkey.
</p>
<p>This function sets a public/private keypair in the
<code class="code">gnutls_certificate_credentials_t</code>  type to be used for authentication
and/or encryption.  <code class="code">spki</code> and  <code class="code">privkey</code> should match otherwise set
signatures cannot be validated. In case of no match this function
returns <code class="code">GNUTLS_E_CERTIFICATE_KEY_MISMATCH</code> . This function should
be called once for the client because there is currently no mechanism
to determine which raw public-key to select for the peer when there
are multiple present. Multiple raw public keys for the server can be
distinghuished by setting the  <code class="code">names</code> .
</p>
<p>Note here that  <code class="code">spki</code> is a raw public-key as defined
in RFC7250. It means that there is no surrounding certificate that
holds the public key and that there is therefore no direct mechanism
to prove the authenticity of this key. The keypair can be used during
a TLS handshake but its authenticity should be established via a
different mechanism (e.g. TOFU or known fingerprint).
</p>
<p>The supported formats are basic unencrypted key, PKCS8, PKCS12,
and the openssl format and will be autodetected.
</p>
<p>If the raw public-key and the private key are given in PEM encoding
then the strings that hold their values must be null terminated.
</p>
<p>Key usage (as defined by X.509 extension (2.5.29.15)) can be explicitly
set because there is no certificate structure around the key to define
this value. See for more info <code class="code">gnutls_x509_crt_get_key_usage()</code> .
</p>
<p>Note that, this function by default returns zero on success and a
negative value on error. Since 3.5.6, when the flag <code class="code">GNUTLS_CERTIFICATE_API_V2</code> 
is set using <code class="code">gnutls_certificate_set_flags()</code>  it returns an index
(greater or equal to zero). That index can be used in other functions
to refer to the added key-pair.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, in case the
key pair does not match <code class="code">GNUTLS_E_CERTIFICATE_KEY_MISMATCH</code>  is returned,
in other erroneous cases a different negative error code is returned.
</p>
<p><strong class="strong">Since:</strong> 3.6.6
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fset_005fretrieve_005ffunction-1"><span>gnutls_certificate_set_retrieve_function<a class="copiable-link" href="#gnutls_005fcertificate_005fset_005fretrieve_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fset_005fretrieve_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fset_005fretrieve_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_certificate_set_retrieve_function</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">cred</var>, gnutls_certificate_retrieve_function * <var class="var">func</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fset_005fretrieve_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">cred</var>: is a <code class="code">gnutls_certificate_credentials_t</code>  type.
</p>
<p><var class="var">func</var>: is the callback function
</p>
<p>This function sets a callback to be called in order to retrieve the
certificate to be used in the handshake. The callback will take control
only if a certificate is requested by the peer. You are advised
to use <code class="code">gnutls_certificate_set_retrieve_function2()</code>  because it
is much more efficient in the processing it requires from gnutls.
</p>
<p>The callback&rsquo;s function prototype is:
int (*callback)(gnutls_session_t, const gnutls_datum_t* req_ca_dn, int nreqs,
const gnutls_pk_algorithm_t* pk_algos, int pk_algos_length, gnutls_retr2_st* st);
</p>
<p><code class="code">req_ca_dn</code> is only used in X.509 certificates.
Contains a list with the CA names that the server considers trusted.
This is a hint and typically the client should send a certificate that is signed
by one of these CAs. These names, when available, are DER encoded. To get a more
meaningful value use the function <code class="code">gnutls_x509_rdn_get()</code> .
</p>
<p><code class="code">pk_algos</code> contains a list with server&rsquo;s acceptable public key algorithms.
The certificate returned should support the server&rsquo;s given algorithms.
</p>
<p><code class="code">st</code> should contain the certificates and private keys.
</p>
<p>If the callback function is provided then gnutls will call it, in the
handshake, after the certificate request message has been received.
</p>
<p>In server side pk_algos and req_ca_dn are NULL.
</p>
<p>The callback function should set the certificate list to be sent,
and return 0 on success. If no certificate was selected then the
number of certificates should be set to zero. The value (-1)
indicates error and the handshake will be terminated. If both certificates
are set in the credentials and a callback is available, the callback
takes predence.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fset_005fverify_005fflags-1"><span>gnutls_certificate_set_verify_flags<a class="copiable-link" href="#gnutls_005fcertificate_005fset_005fverify_005fflags-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fset_005fverify_005fflags"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fset_005fverify_005fflags"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_certificate_set_verify_flags</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">res</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fset_005fverify_005fflags"> &para;</a></span></dt>
<dd><p><var class="var">res</var>: is a gnutls_certificate_credentials_t type
</p>
<p><var class="var">flags</var>: are the flags
</p>
<p>This function will set the flags to be used for verification
of certificates and override any defaults.  The provided flags must be an OR of the
<code class="code">gnutls_certificate_verify_flags</code>  enumerations.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fset_005fverify_005ffunction-1"><span>gnutls_certificate_set_verify_function<a class="copiable-link" href="#gnutls_005fcertificate_005fset_005fverify_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fset_005fverify_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fset_005fverify_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_certificate_set_verify_function</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">cred</var>, gnutls_certificate_verify_function * <var class="var">func</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fset_005fverify_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">cred</var>: is a <code class="code">gnutls_certificate_credentials_t</code>  type.
</p>
<p><var class="var">func</var>: is the callback function
</p>
<p>This function sets a callback to be called when peer&rsquo;s certificate
has been received in order to verify it on receipt rather than
doing after the handshake is completed.
</p>
<p>The callback&rsquo;s function prototype is:
int (*callback)(gnutls_session_t);
</p>
<p>If the callback function is provided then gnutls will call it, in the
handshake, just after the certificate message has been received.
To verify or obtain the certificate the <code class="code">gnutls_certificate_verify_peers2()</code> ,
<code class="code">gnutls_certificate_type_get()</code> , <code class="code">gnutls_certificate_get_peers()</code>  functions
can be used.
</p>
<p>The callback function should return 0 for the handshake to continue
or non-zero to terminate.
</p>
<p><strong class="strong">Since:</strong> 2.10.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fset_005fverify_005flimits-1"><span>gnutls_certificate_set_verify_limits<a class="copiable-link" href="#gnutls_005fcertificate_005fset_005fverify_005flimits-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fset_005fverify_005flimits"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fset_005fverify_005flimits"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_certificate_set_verify_limits</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">res</var>, unsigned int <var class="var">max_bits</var>, unsigned int <var class="var">max_depth</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fset_005fverify_005flimits"> &para;</a></span></dt>
<dd><p><var class="var">res</var>: is a gnutls_certificate_credentials type
</p>
<p><var class="var">max_bits</var>: is the number of bits of an acceptable certificate (default 8200)
</p>
<p><var class="var">max_depth</var>: is maximum depth of the verification of a certificate chain (default 5)
</p>
<p>This function will set some upper limits for the default
verification function, <code class="code">gnutls_certificate_verify_peers2()</code> , to avoid
denial of service attacks.  You can set them to zero to disable
limits.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fset_005fx509_005fcrl-1"><span>gnutls_certificate_set_x509_crl<a class="copiable-link" href="#gnutls_005fcertificate_005fset_005fx509_005fcrl-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fset_005fx509_005fcrl"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fset_005fx509_005fcrl"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_certificate_set_x509_crl</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">res</var>, gnutls_x509_crl_t * <var class="var">crl_list</var>, int <var class="var">crl_list_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fset_005fx509_005fcrl"> &para;</a></span></dt>
<dd><p><var class="var">res</var>: is a <code class="code">gnutls_certificate_credentials_t</code>  type.
</p>
<p><var class="var">crl_list</var>: is a list of trusted CRLs. They should have been verified before.
</p>
<p><var class="var">crl_list_size</var>: holds the size of the crl_list
</p>
<p>This function adds the trusted CRLs in order to verify client or
server certificates.  In case of a client this is not required to
be called if the certificates are not verified using
<code class="code">gnutls_certificate_verify_peers2()</code> .  This function may be called
multiple times.
</p>
<p><strong class="strong">Returns:</strong> number of CRLs processed, or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 2.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fset_005fx509_005fcrl_005ffile-1"><span>gnutls_certificate_set_x509_crl_file<a class="copiable-link" href="#gnutls_005fcertificate_005fset_005fx509_005fcrl_005ffile-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fset_005fx509_005fcrl_005ffile"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fset_005fx509_005fcrl_005ffile"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_certificate_set_x509_crl_file</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">res</var>, const char * <var class="var">crlfile</var>, gnutls_x509_crt_fmt_t <var class="var">type</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fset_005fx509_005fcrl_005ffile"> &para;</a></span></dt>
<dd><p><var class="var">res</var>: is a <code class="code">gnutls_certificate_credentials_t</code>  type.
</p>
<p><var class="var">crlfile</var>: is a file containing the list of verified CRLs (DER or PEM list)
</p>
<p><var class="var">type</var>: is PEM or DER
</p>
<p>This function adds the trusted CRLs in order to verify client or server
certificates.  In case of a client this is not required
to be called if the certificates are not verified using
<code class="code">gnutls_certificate_verify_peers2()</code> .
This function may be called multiple times.
</p>
<p><strong class="strong">Returns:</strong> number of CRLs processed or a negative error code on error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fset_005fx509_005fcrl_005fmem-1"><span>gnutls_certificate_set_x509_crl_mem<a class="copiable-link" href="#gnutls_005fcertificate_005fset_005fx509_005fcrl_005fmem-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fset_005fx509_005fcrl_005fmem"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fset_005fx509_005fcrl_005fmem"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_certificate_set_x509_crl_mem</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">res</var>, const gnutls_datum_t * <var class="var">CRL</var>, gnutls_x509_crt_fmt_t <var class="var">type</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fset_005fx509_005fcrl_005fmem"> &para;</a></span></dt>
<dd><p><var class="var">res</var>: is a <code class="code">gnutls_certificate_credentials_t</code>  type.
</p>
<p><var class="var">CRL</var>: is a list of trusted CRLs. They should have been verified before.
</p>
<p><var class="var">type</var>: is DER or PEM
</p>
<p>This function adds the trusted CRLs in order to verify client or
server certificates.  In case of a client this is not required to
be called if the certificates are not verified using
<code class="code">gnutls_certificate_verify_peers2()</code> .  This function may be called
multiple times.
</p>
<p><strong class="strong">Returns:</strong> number of CRLs processed, or a negative error code on error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fset_005fx509_005fkey-1"><span>gnutls_certificate_set_x509_key<a class="copiable-link" href="#gnutls_005fcertificate_005fset_005fx509_005fkey-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fset_005fx509_005fkey"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fset_005fx509_005fkey"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_certificate_set_x509_key</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">res</var>, gnutls_x509_crt_t * <var class="var">cert_list</var>, int <var class="var">cert_list_size</var>, gnutls_x509_privkey_t <var class="var">key</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fset_005fx509_005fkey"> &para;</a></span></dt>
<dd><p><var class="var">res</var>: is a <code class="code">gnutls_certificate_credentials_t</code>  type.
</p>
<p><var class="var">cert_list</var>: contains a certificate list (path) for the specified private key
</p>
<p><var class="var">cert_list_size</var>: holds the size of the certificate list
</p>
<p><var class="var">key</var>: is a <code class="code">gnutls_x509_privkey_t</code>  key
</p>
<p>This function sets a certificate/private key pair in the
gnutls_certificate_credentials_t type.  This function may be
called more than once, in case multiple keys/certificates exist for
the server.  For clients that wants to send more than their own end
entity certificate (e.g., also an intermediate CA cert) then put
the certificate chain in  <code class="code">cert_list</code> .
</p>
<p>Note that the certificates and keys provided, can be safely deinitialized
after this function is called.
</p>
<p>If that function fails to load the  <code class="code">res</code> type is at an undefined state, it must
not be reused to load other keys or certificates.
</p>
<p>Note that, this function by default returns zero on success and a negative value on error.
Since 3.5.6, when the flag <code class="code">GNUTLS_CERTIFICATE_API_V2</code>  is set using <code class="code">gnutls_certificate_set_flags()</code> 
it returns an index (greater or equal to zero). That index can be used to other functions to refer to the added key-pair.
</p>
<p><strong class="strong">Returns:</strong> On success this functions returns zero, and otherwise a negative value on error (see above for modifying that behavior).
</p>
<p><strong class="strong">Since:</strong> 2.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fset_005fx509_005fkey_005ffile-1"><span>gnutls_certificate_set_x509_key_file<a class="copiable-link" href="#gnutls_005fcertificate_005fset_005fx509_005fkey_005ffile-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fset_005fx509_005fkey_005ffile"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fset_005fx509_005fkey_005ffile"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_certificate_set_x509_key_file</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">res</var>, const char * <var class="var">certfile</var>, const char * <var class="var">keyfile</var>, gnutls_x509_crt_fmt_t <var class="var">type</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fset_005fx509_005fkey_005ffile"> &para;</a></span></dt>
<dd><p><var class="var">res</var>: is a <code class="code">gnutls_certificate_credentials_t</code>  type.
</p>
<p><var class="var">certfile</var>: is a file that containing the certificate list (path) for
the specified private key, in PKCS7 format, or a list of certificates
</p>
<p><var class="var">keyfile</var>: is a file that contains the private key
</p>
<p><var class="var">type</var>: is PEM or DER
</p>
<p>This function sets a certificate/private key pair in the
gnutls_certificate_credentials_t type.  This function may be
called more than once, in case multiple keys/certificates exist for
the server.  For clients that need to send more than its own end
entity certificate, e.g., also an intermediate CA cert, then the
 <code class="code">certfile</code> must contain the ordered certificate chain.
</p>
<p>Note that the names in the certificate provided will be considered
when selecting the appropriate certificate to use (in case of multiple
certificate/key pairs).
</p>
<p>This function can also accept URLs at  <code class="code">keyfile</code> and  <code class="code">certfile</code> . In that case it
will use the private key and certificate indicated by the URLs. Note
that the supported URLs are the ones indicated by <code class="code">gnutls_url_is_supported()</code> .
</p>
<p>In case the  <code class="code">certfile</code> is provided as a PKCS <code class="code">11</code>  URL, then the certificate, and its
present issuers in the token are imported (i.e., forming the required trust chain).
</p>
<p>If that function fails to load the  <code class="code">res</code> structure is at an undefined state, it must
not be reused to load other keys or certificates.
</p>
<p>Note that, this function by default returns zero on success and a negative value on error.
Since 3.5.6, when the flag <code class="code">GNUTLS_CERTIFICATE_API_V2</code>  is set using <code class="code">gnutls_certificate_set_flags()</code> 
it returns an index (greater or equal to zero). That index can be used to other functions to refer to the added key-pair.
</p>
<p><strong class="strong">Returns:</strong> On success this functions returns zero, and otherwise a negative value on error (see above for modifying that behavior).
</p>
<p><strong class="strong">Since:</strong> 3.1.11
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fset_005fx509_005fkey_005ffile2-1"><span>gnutls_certificate_set_x509_key_file2<a class="copiable-link" href="#gnutls_005fcertificate_005fset_005fx509_005fkey_005ffile2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fset_005fx509_005fkey_005ffile2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fset_005fx509_005fkey_005ffile2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_certificate_set_x509_key_file2</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">res</var>, const char * <var class="var">certfile</var>, const char * <var class="var">keyfile</var>, gnutls_x509_crt_fmt_t <var class="var">type</var>, const char * <var class="var">pass</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fset_005fx509_005fkey_005ffile2"> &para;</a></span></dt>
<dd><p><var class="var">res</var>: is a <code class="code">gnutls_certificate_credentials_t</code>  type.
</p>
<p><var class="var">certfile</var>: is a file that containing the certificate list (path) for
the specified private key, in PKCS7 format, or a list of certificates
</p>
<p><var class="var">keyfile</var>: is a file that contains the private key
</p>
<p><var class="var">type</var>: is PEM or DER
</p>
<p><var class="var">pass</var>: is the password of the key
</p>
<p><var class="var">flags</var>: an ORed sequence of gnutls_pkcs_encrypt_flags_t
</p>
<p>This function sets a certificate/private key pair in the
gnutls_certificate_credentials_t type.  This function may be
called more than once, in case multiple keys/certificates exist for
the server.  For clients that need to send more than its own end
entity certificate, e.g., also an intermediate CA cert, then the
 <code class="code">certfile</code> must contain the ordered certificate chain.
</p>
<p>Note that the names in the certificate provided will be considered
when selecting the appropriate certificate to use (in case of multiple
certificate/key pairs).
</p>
<p>This function can also accept URLs at  <code class="code">keyfile</code> and  <code class="code">certfile</code> . In that case it
will use the private key and certificate indicated by the URLs. Note
that the supported URLs are the ones indicated by <code class="code">gnutls_url_is_supported()</code> .
Before GnuTLS 3.4.0 when a URL was specified, the  <code class="code">pass</code> part was ignored and a
PIN callback had to be registered, this is no longer the case in current releases.
</p>
<p>In case the  <code class="code">certfile</code> is provided as a PKCS <code class="code">11</code>  URL, then the certificate, and its
present issuers in the token are imported (i.e., forming the required trust chain).
</p>
<p>If that function fails to load the  <code class="code">res</code> structure is at an undefined state, it must
not be reused to load other keys or certificates.
</p>
<p>Note that, this function by default returns zero on success and a negative value on error.
Since 3.5.6, when the flag <code class="code">GNUTLS_CERTIFICATE_API_V2</code>  is set using <code class="code">gnutls_certificate_set_flags()</code> 
it returns an index (greater or equal to zero). That index can be used to other functions to refer to the added key-pair.
</p>
<p><strong class="strong">Returns:</strong> On success this functions returns zero, and otherwise a negative value on error (see above for modifying that behavior).
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fset_005fx509_005fkey_005fmem-1"><span>gnutls_certificate_set_x509_key_mem<a class="copiable-link" href="#gnutls_005fcertificate_005fset_005fx509_005fkey_005fmem-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fset_005fx509_005fkey_005fmem"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fset_005fx509_005fkey_005fmem"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_certificate_set_x509_key_mem</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">res</var>, const gnutls_datum_t * <var class="var">cert</var>, const gnutls_datum_t * <var class="var">key</var>, gnutls_x509_crt_fmt_t <var class="var">type</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fset_005fx509_005fkey_005fmem"> &para;</a></span></dt>
<dd><p><var class="var">res</var>: is a <code class="code">gnutls_certificate_credentials_t</code>  type.
</p>
<p><var class="var">cert</var>: contains a certificate list (path) for the specified private key
</p>
<p><var class="var">key</var>: is the private key, or <code class="code">NULL</code> 
</p>
<p><var class="var">type</var>: is PEM or DER
</p>
<p>This function sets a certificate/private key pair in the
gnutls_certificate_credentials_t type. This function may be called
more than once, in case multiple keys/certificates exist for the
server.
</p>
<p>Note that the keyUsage (2.5.29.15) PKIX extension in X.509 certificates
is supported. This means that certificates intended for signing cannot
be used for ciphersuites that require encryption.
</p>
<p>If the certificate and the private key are given in PEM encoding
then the strings that hold their values must be null terminated.
</p>
<p>The  <code class="code">key</code> may be <code class="code">NULL</code>  if you are using a sign callback, see
<code class="code">gnutls_sign_callback_set()</code> .
</p>
<p>Note that, this function by default returns zero on success and a negative value on error.
Since 3.5.6, when the flag <code class="code">GNUTLS_CERTIFICATE_API_V2</code>  is set using <code class="code">gnutls_certificate_set_flags()</code> 
it returns an index (greater or equal to zero). That index can be used to other functions to refer to the added key-pair.
</p>
<p><strong class="strong">Returns:</strong> On success this functions returns zero, and otherwise a negative value on error (see above for modifying that behavior).
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fset_005fx509_005fkey_005fmem2-1"><span>gnutls_certificate_set_x509_key_mem2<a class="copiable-link" href="#gnutls_005fcertificate_005fset_005fx509_005fkey_005fmem2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fset_005fx509_005fkey_005fmem2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fset_005fx509_005fkey_005fmem2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_certificate_set_x509_key_mem2</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">res</var>, const gnutls_datum_t * <var class="var">cert</var>, const gnutls_datum_t * <var class="var">key</var>, gnutls_x509_crt_fmt_t <var class="var">type</var>, const char * <var class="var">pass</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fset_005fx509_005fkey_005fmem2"> &para;</a></span></dt>
<dd><p><var class="var">res</var>: is a <code class="code">gnutls_certificate_credentials_t</code>  type.
</p>
<p><var class="var">cert</var>: contains a certificate list (path) for the specified private key
</p>
<p><var class="var">key</var>: is the private key, or <code class="code">NULL</code> 
</p>
<p><var class="var">type</var>: is PEM or DER
</p>
<p><var class="var">pass</var>: is the key&rsquo;s password
</p>
<p><var class="var">flags</var>: an ORed sequence of gnutls_pkcs_encrypt_flags_t
</p>
<p>This function sets a certificate/private key pair in the
gnutls_certificate_credentials_t type. This function may be called
more than once, in case multiple keys/certificates exist for the
server.
</p>
<p>Note that the keyUsage (2.5.29.15) PKIX extension in X.509 certificates
is supported. This means that certificates intended for signing cannot
be used for ciphersuites that require encryption.
</p>
<p>If the certificate and the private key are given in PEM encoding
then the strings that hold their values must be null terminated.
</p>
<p>The  <code class="code">key</code> may be <code class="code">NULL</code>  if you are using a sign callback, see
<code class="code">gnutls_sign_callback_set()</code> .
</p>
<p>Note that, this function by default returns zero on success and a negative value on error.
Since 3.5.6, when the flag <code class="code">GNUTLS_CERTIFICATE_API_V2</code>  is set using <code class="code">gnutls_certificate_set_flags()</code> 
it returns an index (greater or equal to zero). That index can be used to other functions to refer to the added key-pair.
</p>
<p><strong class="strong">Returns:</strong> On success this functions returns zero, and otherwise a negative value on error (see above for modifying that behavior).
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fset_005fx509_005fsimple_005fpkcs12_005ffile-1"><span>gnutls_certificate_set_x509_simple_pkcs12_file<a class="copiable-link" href="#gnutls_005fcertificate_005fset_005fx509_005fsimple_005fpkcs12_005ffile-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fset_005fx509_005fsimple_005fpkcs12_005ffile"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fset_005fx509_005fsimple_005fpkcs12_005ffile"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_certificate_set_x509_simple_pkcs12_file</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">res</var>, const char * <var class="var">pkcs12file</var>, gnutls_x509_crt_fmt_t <var class="var">type</var>, const char * <var class="var">password</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fset_005fx509_005fsimple_005fpkcs12_005ffile"> &para;</a></span></dt>
<dd><p><var class="var">res</var>: is a <code class="code">gnutls_certificate_credentials_t</code>  type.
</p>
<p><var class="var">pkcs12file</var>: filename of file containing PKCS<code class="code">12</code>  blob.
</p>
<p><var class="var">type</var>: is PEM or DER of the  <code class="code">pkcs12file</code> .
</p>
<p><var class="var">password</var>: optional password used to decrypt PKCS<code class="code">12</code>  file, bags and keys.
</p>
<p>This function sets a certificate/private key pair and/or a CRL in
the gnutls_certificate_credentials_t type.  This function may
be called more than once (in case multiple keys/certificates exist
for the server).
</p>
<p>PKCS<code class="code">12</code>  files with a MAC, encrypted bags and PKCS <code class="code">8</code> 
private keys are supported. However,
only password based security, and the same password for all
operations, are supported.
</p>
<p>PKCS<code class="code">12</code>  file may contain many keys and/or certificates, and this
function will try to auto-detect based on the key ID the certificate
and key pair to use. If the PKCS<code class="code">12</code>  file contain the issuer of
the selected certificate, it will be appended to the certificate
to form a chain.
</p>
<p>If more than one private keys are stored in the PKCS<code class="code">12</code>  file,
then only one key will be read (and it is undefined which one).
</p>
<p>It is believed that the limitations of this function is acceptable
for most usage, and that any more flexibility would introduce
complexity that would make it harder to use this functionality at
all.
</p>
<p>Note that, this function by default returns zero on success and a negative value on error.
Since 3.5.6, when the flag <code class="code">GNUTLS_CERTIFICATE_API_V2</code>  is set using <code class="code">gnutls_certificate_set_flags()</code> 
it returns an index (greater or equal to zero). That index can be used to other functions to refer to the added key-pair.
</p>
<p><strong class="strong">Returns:</strong> On success this functions returns zero, and otherwise a negative value on error (see above for modifying that behavior).
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fset_005fx509_005fsimple_005fpkcs12_005fmem-1"><span>gnutls_certificate_set_x509_simple_pkcs12_mem<a class="copiable-link" href="#gnutls_005fcertificate_005fset_005fx509_005fsimple_005fpkcs12_005fmem-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fset_005fx509_005fsimple_005fpkcs12_005fmem"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fset_005fx509_005fsimple_005fpkcs12_005fmem"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_certificate_set_x509_simple_pkcs12_mem</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">res</var>, const gnutls_datum_t * <var class="var">p12blob</var>, gnutls_x509_crt_fmt_t <var class="var">type</var>, const char * <var class="var">password</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fset_005fx509_005fsimple_005fpkcs12_005fmem"> &para;</a></span></dt>
<dd><p><var class="var">res</var>: is a <code class="code">gnutls_certificate_credentials_t</code>  type.
</p>
<p><var class="var">p12blob</var>: the PKCS<code class="code">12</code>  blob.
</p>
<p><var class="var">type</var>: is PEM or DER of the  <code class="code">pkcs12file</code> .
</p>
<p><var class="var">password</var>: optional password used to decrypt PKCS<code class="code">12</code>  file, bags and keys.
</p>
<p>This function sets a certificate/private key pair and/or a CRL in
the gnutls_certificate_credentials_t type.  This function may
be called more than once (in case multiple keys/certificates exist
for the server).
</p>
<p>Encrypted PKCS<code class="code">12</code>  bags and PKCS<code class="code">8</code>  private keys are supported.  However,
only password based security, and the same password for all
operations, are supported.
</p>
<p>PKCS<code class="code">12</code>  file may contain many keys and/or certificates, and this
function will try to auto-detect based on the key ID the certificate
and key pair to use. If the PKCS<code class="code">12</code>  file contain the issuer of
the selected certificate, it will be appended to the certificate
to form a chain.
</p>
<p>If more than one private keys are stored in the PKCS<code class="code">12</code>  file,
then only one key will be read (and it is undefined which one).
</p>
<p>It is believed that the limitations of this function is acceptable
for most usage, and that any more flexibility would introduce
complexity that would make it harder to use this functionality at
all.
</p>
<p>Note that, this function by default returns zero on success and a negative value on error.
Since 3.5.6, when the flag <code class="code">GNUTLS_CERTIFICATE_API_V2</code>  is set using <code class="code">gnutls_certificate_set_flags()</code> 
it returns an index (greater or equal to zero). That index can be used to other functions to refer to the added key-pair.
</p>
<p><strong class="strong">Returns:</strong> On success this functions returns zero, and otherwise a negative value on error (see above for modifying that behavior).
</p>
<p><strong class="strong">Since:</strong> 2.8.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fset_005fx509_005fsystem_005ftrust-1"><span>gnutls_certificate_set_x509_system_trust<a class="copiable-link" href="#gnutls_005fcertificate_005fset_005fx509_005fsystem_005ftrust-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fset_005fx509_005fsystem_005ftrust"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fset_005fx509_005fsystem_005ftrust-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_certificate_set_x509_system_trust</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">cred</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fset_005fx509_005fsystem_005ftrust-1"> &para;</a></span></dt>
<dd><p><var class="var">cred</var>: is a <code class="code">gnutls_certificate_credentials_t</code>  type.
</p>
<p>This function adds the system&rsquo;s default trusted CAs in order to
verify client or server certificates.
</p>
<p>In the case the system is currently unsupported <code class="code">GNUTLS_E_UNIMPLEMENTED_FEATURE</code> 
is returned.
</p>
<p><strong class="strong">Returns:</strong> the number of certificates processed or a negative error code
on error.
</p>
<p><strong class="strong">Since:</strong> 3.0.20
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fset_005fx509_005ftrust-1"><span>gnutls_certificate_set_x509_trust<a class="copiable-link" href="#gnutls_005fcertificate_005fset_005fx509_005ftrust-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fset_005fx509_005ftrust"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fset_005fx509_005ftrust"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_certificate_set_x509_trust</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">res</var>, gnutls_x509_crt_t * <var class="var">ca_list</var>, int <var class="var">ca_list_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fset_005fx509_005ftrust"> &para;</a></span></dt>
<dd><p><var class="var">res</var>: is a <code class="code">gnutls_certificate_credentials_t</code>  type.
</p>
<p><var class="var">ca_list</var>: is a list of trusted CAs
</p>
<p><var class="var">ca_list_size</var>: holds the size of the CA list
</p>
<p>This function adds the trusted CAs in order to verify client
or server certificates. In case of a client this is not required
to be called if the certificates are not verified using
<code class="code">gnutls_certificate_verify_peers2()</code> .
This function may be called multiple times.
</p>
<p>In case of a server the CAs set here will be sent to the client if
a certificate request is sent. This can be disabled using
<code class="code">gnutls_certificate_send_x509_rdn_sequence()</code> .
</p>
<p><strong class="strong">Returns:</strong> the number of certificates processed or a negative error code
on error.
</p>
<p><strong class="strong">Since:</strong> 2.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fset_005fx509_005ftrust_005fdir-1"><span>gnutls_certificate_set_x509_trust_dir<a class="copiable-link" href="#gnutls_005fcertificate_005fset_005fx509_005ftrust_005fdir-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fset_005fx509_005ftrust_005fdir"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fset_005fx509_005ftrust_005fdir"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_certificate_set_x509_trust_dir</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">cred</var>, const char * <var class="var">ca_dir</var>, gnutls_x509_crt_fmt_t <var class="var">type</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fset_005fx509_005ftrust_005fdir"> &para;</a></span></dt>
<dd><p><var class="var">cred</var>: is a <code class="code">gnutls_certificate_credentials_t</code>  type.
</p>
<p><var class="var">ca_dir</var>: is a directory containing the list of trusted CAs (DER or PEM list)
</p>
<p><var class="var">type</var>: is PEM or DER
</p>
<p>This function adds the trusted CAs present in the directory in order to
verify client or server certificates. This function is identical
to <code class="code">gnutls_certificate_set_x509_trust_file()</code>  but loads all certificates
in a directory.
</p>
<p><strong class="strong">Returns:</strong> the number of certificates processed
</p>
<p><strong class="strong">Since:</strong> 3.3.6
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fset_005fx509_005ftrust_005ffile-1"><span>gnutls_certificate_set_x509_trust_file<a class="copiable-link" href="#gnutls_005fcertificate_005fset_005fx509_005ftrust_005ffile-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fset_005fx509_005ftrust_005ffile"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fset_005fx509_005ftrust_005ffile"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_certificate_set_x509_trust_file</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">cred</var>, const char * <var class="var">cafile</var>, gnutls_x509_crt_fmt_t <var class="var">type</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fset_005fx509_005ftrust_005ffile"> &para;</a></span></dt>
<dd><p><var class="var">cred</var>: is a <code class="code">gnutls_certificate_credentials_t</code>  type.
</p>
<p><var class="var">cafile</var>: is a file containing the list of trusted CAs (DER or PEM list)
</p>
<p><var class="var">type</var>: is PEM or DER
</p>
<p>This function adds the trusted CAs in order to verify client or
server certificates. In case of a client this is not required to
be called if the certificates are not verified using
<code class="code">gnutls_certificate_verify_peers2()</code> .  This function may be called
multiple times.
</p>
<p>In case of a server the names of the CAs set here will be sent to
the client if a certificate request is sent. This can be disabled
using <code class="code">gnutls_certificate_send_x509_rdn_sequence()</code> .
</p>
<p>This function can also accept URLs. In that case it
will import all certificates that are marked as trusted. Note
that the supported URLs are the ones indicated by <code class="code">gnutls_url_is_supported()</code> .
</p>
<p><strong class="strong">Returns:</strong> the number of certificates processed
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fset_005fx509_005ftrust_005fmem-1"><span>gnutls_certificate_set_x509_trust_mem<a class="copiable-link" href="#gnutls_005fcertificate_005fset_005fx509_005ftrust_005fmem-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fset_005fx509_005ftrust_005fmem"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fset_005fx509_005ftrust_005fmem"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_certificate_set_x509_trust_mem</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">res</var>, const gnutls_datum_t * <var class="var">ca</var>, gnutls_x509_crt_fmt_t <var class="var">type</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fset_005fx509_005ftrust_005fmem"> &para;</a></span></dt>
<dd><p><var class="var">res</var>: is a <code class="code">gnutls_certificate_credentials_t</code>  type.
</p>
<p><var class="var">ca</var>: is a list of trusted CAs or a DER certificate
</p>
<p><var class="var">type</var>: is DER or PEM
</p>
<p>This function adds the trusted CAs in order to verify client or
server certificates. In case of a client this is not required to be
called if the certificates are not verified using
<code class="code">gnutls_certificate_verify_peers2()</code> .  This function may be called
multiple times.
</p>
<p>In case of a server the CAs set here will be sent to the client if
a certificate request is sent. This can be disabled using
<code class="code">gnutls_certificate_send_x509_rdn_sequence()</code> .
</p>
<p><strong class="strong">Returns:</strong> the number of certificates processed or a negative error code
on error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005ftype_005fget-1"><span>gnutls_certificate_type_get<a class="copiable-link" href="#gnutls_005fcertificate_005ftype_005fget-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005ftype_005fget"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005ftype_005fget"><span class="category-def">Function: </span><span><code class="def-type">gnutls_certificate_type_t</code> <strong class="def-name">gnutls_certificate_type_get</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005ftype_005fget"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>This function returns the type of the certificate that is negotiated
for this side to send to the peer. The certificate type is by default
X.509, unless an alternative certificate type is enabled by
<code class="code">gnutls_init()</code>  and negotiated during the session.
</p>
<p>Resumed sessions will return the certificate type that was negotiated
and used in the original session.
</p>
<p>As of version 3.6.4 it is recommended to use
<code class="code">gnutls_certificate_type_get2()</code>  which is more fine-grained.
</p>
<p><strong class="strong">Returns:</strong> the currently used <code class="code">gnutls_certificate_type_t</code>  certificate
type as negotiated for &rsquo;our&rsquo; side of the connection.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005ftype_005fget2-1"><span>gnutls_certificate_type_get2<a class="copiable-link" href="#gnutls_005fcertificate_005ftype_005fget2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005ftype_005fget2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005ftype_005fget2"><span class="category-def">Function: </span><span><code class="def-type">gnutls_certificate_type_t</code> <strong class="def-name">gnutls_certificate_type_get2</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_ctype_target_t <var class="var">target</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005ftype_005fget2"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">target</var>: is a <code class="code">gnutls_ctype_target_t</code>  type.
</p>
<p>This function returns the type of the certificate that a side
is negotiated to use.  The certificate type is by default X.509,
unless an alternative certificate type is enabled by <code class="code">gnutls_init()</code>  and
negotiated during the session.
</p>
<p>The  <code class="code">target</code> parameter specifies whether to request the negotiated
certificate type for the client (<code class="code">GNUTLS_CTYPE_CLIENT</code> ),
or for the server (<code class="code">GNUTLS_CTYPE_SERVER</code> ). Additionally, in P2P mode
connection set up where you don&rsquo;t know in advance who will be client
and who will be server you can use the flag (<code class="code">GNUTLS_CTYPE_OURS</code> ) and
(<code class="code">GNUTLS_CTYPE_PEERS</code> ) to retrieve the corresponding certificate types.
</p>
<p>Resumed sessions will return the certificate type that was negotiated
and used in the original session. That is, this function can be used
to reliably determine the type of the certificate returned by
<code class="code">gnutls_certificate_get_peers()</code> .
</p>
<p><strong class="strong">Returns:</strong> the currently used <code class="code">gnutls_certificate_type_t</code>  certificate
type for the client or the server.
</p>
<p><strong class="strong">Since:</strong> 3.6.4
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005ftype_005fget_005fid-1"><span>gnutls_certificate_type_get_id<a class="copiable-link" href="#gnutls_005fcertificate_005ftype_005fget_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005ftype_005fget_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005ftype_005fget_005fid"><span class="category-def">Function: </span><span><code class="def-type">gnutls_certificate_type_t</code> <strong class="def-name">gnutls_certificate_type_get_id</strong> <code class="def-code-arguments">(const char * <var class="var">name</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005ftype_005fget_005fid"> &para;</a></span></dt>
<dd><p><var class="var">name</var>: is a certificate type name
</p>
<p>The names are compared in a case insensitive way.
</p>
<p><strong class="strong">Returns:</strong> a <code class="code">gnutls_certificate_type_t</code>  for the specified in a
string certificate type, or <code class="code">GNUTLS_CRT_UNKNOWN</code>  on error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005ftype_005fget_005fname-1"><span>gnutls_certificate_type_get_name<a class="copiable-link" href="#gnutls_005fcertificate_005ftype_005fget_005fname-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005ftype_005fget_005fname"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005ftype_005fget_005fname"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_certificate_type_get_name</strong> <code class="def-code-arguments">(gnutls_certificate_type_t <var class="var">type</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005ftype_005fget_005fname"> &para;</a></span></dt>
<dd><p><var class="var">type</var>: is a certificate type
</p>
<p>Convert a <code class="code">gnutls_certificate_type_t</code>  type to a string.
</p>
<p><strong class="strong">Returns:</strong> a string that contains the name of the specified
certificate type, or <code class="code">NULL</code>  in case of unknown types.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005ftype_005flist-1"><span>gnutls_certificate_type_list<a class="copiable-link" href="#gnutls_005fcertificate_005ftype_005flist-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005ftype_005flist"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005ftype_005flist"><span class="category-def">Function: </span><span><code class="def-type">const gnutls_certificate_type_t *</code> <strong class="def-name">gnutls_certificate_type_list</strong> <code class="def-code-arguments">( <var class="var">void</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005ftype_005flist"> &para;</a></span></dt>
<dd>
<p>Get a list of certificate types.
</p>
<p><strong class="strong">Returns:</strong> a (0)-terminated list of <code class="code">gnutls_certificate_type_t</code> 
integers indicating the available certificate types.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fverification_005fstatus_005fprint-1"><span>gnutls_certificate_verification_status_print<a class="copiable-link" href="#gnutls_005fcertificate_005fverification_005fstatus_005fprint-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fverification_005fstatus_005fprint"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fverification_005fstatus_005fprint"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_certificate_verification_status_print</strong> <code class="def-code-arguments">(unsigned int <var class="var">status</var>, gnutls_certificate_type_t <var class="var">type</var>, gnutls_datum_t * <var class="var">out</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fverification_005fstatus_005fprint"> &para;</a></span></dt>
<dd><p><var class="var">status</var>: The status flags to be printed
</p>
<p><var class="var">type</var>: The certificate type
</p>
<p><var class="var">out</var>: Newly allocated datum with (0) terminated string.
</p>
<p><var class="var">flags</var>: should be zero
</p>
<p>This function will pretty print the status of a verification
process &ndash; eg. the one obtained by <code class="code">gnutls_certificate_verify_peers3()</code> .
</p>
<p>The output  <code class="code">out</code> needs to be deallocated using <code class="code">gnutls_free()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.1.4
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fverify_005fpeers-1"><span>gnutls_certificate_verify_peers<a class="copiable-link" href="#gnutls_005fcertificate_005fverify_005fpeers-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fverify_005fpeers"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fverify_005fpeers"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_certificate_verify_peers</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_typed_vdata_st * <var class="var">data</var>, unsigned int <var class="var">elements</var>, unsigned int * <var class="var">status</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fverify_005fpeers"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a gnutls session
</p>
<p><var class="var">data</var>: an array of typed data
</p>
<p><var class="var">elements</var>: the number of data elements
</p>
<p><var class="var">status</var>: is the output of the verification
</p>
<p>This function will verify the peer&rsquo;s certificate and store the
the status in the  <code class="code">status</code> variable as a bitwise OR of gnutls_certificate_status_t
values or zero if the certificate is trusted. Note that value in  <code class="code">status</code> is set only when the return value of this function is success (i.e, failure
to trust a certificate does not imply a negative return value).
The default verification flags used by this function can be overridden
using <code class="code">gnutls_certificate_set_verify_flags()</code> . See the documentation
of <code class="code">gnutls_certificate_verify_peers2()</code>  for details in the verification process.
</p>
<p>This function will take into account the stapled OCSP responses sent by the server,
as well as the following X.509 certificate extensions: Name Constraints,
Key Usage, and Basic Constraints (pathlen).
</p>
<p>The acceptable  <code class="code">data</code> types are <code class="code">GNUTLS_DT_DNS_HOSTNAME</code> , <code class="code">GNUTLS_DT_RFC822NAME</code>  and <code class="code">GNUTLS_DT_KEY_PURPOSE_OID</code> .
The former two accept as data a null-terminated hostname or email address, and the latter a null-terminated
object identifier (e.g., <code class="code">GNUTLS_KP_TLS_WWW_SERVER</code> ).
</p>
<p>If a DNS hostname is provided then this function will compare
the hostname in the certificate against the given. If names do not match the
<code class="code">GNUTLS_CERT_UNEXPECTED_OWNER</code>  status flag will be set.
If a key purpose OID is provided and the end-certificate contains the extended key
usage PKIX extension, it will be required to be have the provided key purpose
or be marked for any purpose, otherwise verification status will have the
<code class="code">GNUTLS_CERT_SIGNER_CONSTRAINTS_FAILURE</code>  flag set.
</p>
<p>To avoid denial of service attacks some
default upper limits regarding the certificate key size and chain
size are set. To override them use <code class="code">gnutls_certificate_set_verify_limits()</code> .
</p>
<p>Note that when using raw public-keys verification will not work because there is
no corresponding certificate body belonging to the raw key that can be verified. In that
case this function will return <code class="code">GNUTLS_E_INVALID_REQUEST</code> .
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  (0) when the validation is performed, or a negative error code otherwise.
A successful error code means that the  <code class="code">status</code> parameter must be checked to obtain the validation status.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fverify_005fpeers2-1"><span>gnutls_certificate_verify_peers2<a class="copiable-link" href="#gnutls_005fcertificate_005fverify_005fpeers2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fverify_005fpeers2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fverify_005fpeers2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_certificate_verify_peers2</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, unsigned int * <var class="var">status</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fverify_005fpeers2"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a gnutls session
</p>
<p><var class="var">status</var>: is the output of the verification
</p>
<p>This function will verify the peer&rsquo;s certificate and store
the status in the  <code class="code">status</code> variable as a bitwise OR of gnutls_certificate_status_t
values or zero if the certificate is trusted. Note that value in  <code class="code">status</code> is set only when the return value of this function is success (i.e, failure
to trust a certificate does not imply a negative return value).
The default verification flags used by this function can be overridden
using <code class="code">gnutls_certificate_set_verify_flags()</code> .
</p>
<p>This function will take into account the stapled OCSP responses sent by the server,
as well as the following X.509 certificate extensions: Name Constraints,
Key Usage, and Basic Constraints (pathlen).
</p>
<p>Note that you must also check the peer&rsquo;s name in order to check if
the verified certificate belongs to the actual peer, see <code class="code">gnutls_x509_crt_check_hostname()</code> ,
or use <code class="code">gnutls_certificate_verify_peers3()</code> .
</p>
<p>To avoid denial of service attacks some
default upper limits regarding the certificate key size and chain
size are set. To override them use <code class="code">gnutls_certificate_set_verify_limits()</code> .
</p>
<p>Note that when using raw public-keys verification will not work because there is
no corresponding certificate body belonging to the raw key that can be verified. In that
case this function will return <code class="code">GNUTLS_E_INVALID_REQUEST</code> .
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  (0) when the validation is performed, or a negative error code otherwise.
A successful error code means that the  <code class="code">status</code> parameter must be checked to obtain the validation status.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fverify_005fpeers3-1"><span>gnutls_certificate_verify_peers3<a class="copiable-link" href="#gnutls_005fcertificate_005fverify_005fpeers3-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fverify_005fpeers3"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fverify_005fpeers3"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_certificate_verify_peers3</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, const char * <var class="var">hostname</var>, unsigned int * <var class="var">status</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fverify_005fpeers3"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a gnutls session
</p>
<p><var class="var">hostname</var>: is the expected name of the peer; may be <code class="code">NULL</code> 
</p>
<p><var class="var">status</var>: is the output of the verification
</p>
<p>This function will verify the peer&rsquo;s certificate and store the
the status in the  <code class="code">status</code> variable as a bitwise OR of gnutls_certificate_status_t
values or zero if the certificate is trusted. Note that value in  <code class="code">status</code> is set only when the return value of this function is success (i.e, failure
to trust a certificate does not imply a negative return value).
The default verification flags used by this function can be overridden
using <code class="code">gnutls_certificate_set_verify_flags()</code> . See the documentation
of <code class="code">gnutls_certificate_verify_peers2()</code>  for details in the verification process.
</p>
<p>This function will take into account the stapled OCSP responses sent by the server,
as well as the following X.509 certificate extensions: Name Constraints,
Key Usage, and Basic Constraints (pathlen).
</p>
<p>If the  <code class="code">hostname</code> provided is non-NULL then this function will compare
the hostname in the certificate against it. The comparison will follow
the RFC6125 recommendations. If names do not match the
<code class="code">GNUTLS_CERT_UNEXPECTED_OWNER</code>  status flag will be set.
</p>
<p>In order to verify the purpose of the end-certificate (by checking the extended
key usage), use <code class="code">gnutls_certificate_verify_peers()</code> .
</p>
<p>To avoid denial of service attacks some
default upper limits regarding the certificate key size and chain
size are set. To override them use <code class="code">gnutls_certificate_set_verify_limits()</code> .
</p>
<p>Note that when using raw public-keys verification will not work because there is
no corresponding certificate body belonging to the raw key that can be verified. In that
case this function will return <code class="code">GNUTLS_E_INVALID_REQUEST</code> .
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  (0) when the validation is performed, or a negative error code otherwise.
A successful error code means that the  <code class="code">status</code> parameter must be checked to obtain the validation status.
</p>
<p><strong class="strong">Since:</strong> 3.1.4
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcheck_005fversion-1"><span>gnutls_check_version<a class="copiable-link" href="#gnutls_005fcheck_005fversion-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcheck_005fversion"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcheck_005fversion"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_check_version</strong> <code class="def-code-arguments">(const char * <var class="var">req_version</var>)</code><a class="copiable-link" href="#index-gnutls_005fcheck_005fversion"> &para;</a></span></dt>
<dd><p><var class="var">req_version</var>: version string to compare with, or <code class="code">NULL</code> .
</p>
<p>Check the GnuTLS Library version against the provided string.
See <code class="code">GNUTLS_VERSION</code>  for a suitable  <code class="code">req_version</code> string.
</p>
<p>See also <code class="code">gnutls_check_version_numeric()</code> , which provides this
functionality as a macro.
</p>
<p><strong class="strong">Returns:</strong> Check that the version of the library is at
minimum the one given as a string in  <code class="code">req_version</code> and return the
actual version string of the library; return <code class="code">NULL</code>  if the
condition is not met.  If <code class="code">NULL</code>  is passed to this function no
check is done and only the version string is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcipher_005fget-1"><span>gnutls_cipher_get<a class="copiable-link" href="#gnutls_005fcipher_005fget-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcipher_005fget"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcipher_005fget"><span class="category-def">Function: </span><span><code class="def-type">gnutls_cipher_algorithm_t</code> <strong class="def-name">gnutls_cipher_get</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fcipher_005fget"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>Get the currently used cipher.
</p>
<p><strong class="strong">Returns:</strong> the currently used cipher, a <code class="code">gnutls_cipher_algorithm_t</code> 
type.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcipher_005fget_005fid-1"><span>gnutls_cipher_get_id<a class="copiable-link" href="#gnutls_005fcipher_005fget_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcipher_005fget_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcipher_005fget_005fid"><span class="category-def">Function: </span><span><code class="def-type">gnutls_cipher_algorithm_t</code> <strong class="def-name">gnutls_cipher_get_id</strong> <code class="def-code-arguments">(const char * <var class="var">name</var>)</code><a class="copiable-link" href="#index-gnutls_005fcipher_005fget_005fid"> &para;</a></span></dt>
<dd><p><var class="var">name</var>: is a cipher algorithm name
</p>
<p>The names are compared in a case insensitive way.
</p>
<p><strong class="strong">Returns:</strong> return a <code class="code">gnutls_cipher_algorithm_t</code>  value corresponding to
the specified cipher, or <code class="code">GNUTLS_CIPHER_UNKNOWN</code>  on error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcipher_005fget_005fkey_005fsize-1"><span>gnutls_cipher_get_key_size<a class="copiable-link" href="#gnutls_005fcipher_005fget_005fkey_005fsize-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcipher_005fget_005fkey_005fsize"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcipher_005fget_005fkey_005fsize"><span class="category-def">Function: </span><span><code class="def-type">size_t</code> <strong class="def-name">gnutls_cipher_get_key_size</strong> <code class="def-code-arguments">(gnutls_cipher_algorithm_t <var class="var">algorithm</var>)</code><a class="copiable-link" href="#index-gnutls_005fcipher_005fget_005fkey_005fsize"> &para;</a></span></dt>
<dd><p><var class="var">algorithm</var>: is an encryption algorithm
</p>
<p>This function returns the key size of the provided algorithm.
</p>
<p><strong class="strong">Returns:</strong> length (in bytes) of the given cipher&rsquo;s key size, or 0 if
the given cipher is invalid.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcipher_005fget_005fname-1"><span>gnutls_cipher_get_name<a class="copiable-link" href="#gnutls_005fcipher_005fget_005fname-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcipher_005fget_005fname"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcipher_005fget_005fname"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_cipher_get_name</strong> <code class="def-code-arguments">(gnutls_cipher_algorithm_t <var class="var">algorithm</var>)</code><a class="copiable-link" href="#index-gnutls_005fcipher_005fget_005fname"> &para;</a></span></dt>
<dd><p><var class="var">algorithm</var>: is an encryption algorithm
</p>
<p>Convert a <code class="code">gnutls_cipher_algorithm_t</code>  type to a string.
</p>
<p><strong class="strong">Returns:</strong> a pointer to a string that contains the name of the
specified cipher, or <code class="code">NULL</code> .
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcipher_005flist-1"><span>gnutls_cipher_list<a class="copiable-link" href="#gnutls_005fcipher_005flist-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcipher_005flist"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcipher_005flist"><span class="category-def">Function: </span><span><code class="def-type">const gnutls_cipher_algorithm_t *</code> <strong class="def-name">gnutls_cipher_list</strong> <code class="def-code-arguments">( <var class="var">void</var>)</code><a class="copiable-link" href="#index-gnutls_005fcipher_005flist"> &para;</a></span></dt>
<dd>
<p>Get a list of supported cipher algorithms.  Note that not
necessarily all ciphers are supported as TLS cipher suites.  For
example, DES is not supported as a cipher suite, but is supported
for other purposes (e.g., PKCS<code class="code">8</code>  or similar).
</p>
<p>This function is not thread safe.
</p>
<p><strong class="strong">Returns:</strong> a (0)-terminated list of <code class="code">gnutls_cipher_algorithm_t</code> 
integers indicating the available ciphers.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcipher_005fsuite_005fget_005fname-1"><span>gnutls_cipher_suite_get_name<a class="copiable-link" href="#gnutls_005fcipher_005fsuite_005fget_005fname-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcipher_005fsuite_005fget_005fname"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcipher_005fsuite_005fget_005fname"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_cipher_suite_get_name</strong> <code class="def-code-arguments">(gnutls_kx_algorithm_t <var class="var">kx_algorithm</var>, gnutls_cipher_algorithm_t <var class="var">cipher_algorithm</var>, gnutls_mac_algorithm_t <var class="var">mac_algorithm</var>)</code><a class="copiable-link" href="#index-gnutls_005fcipher_005fsuite_005fget_005fname"> &para;</a></span></dt>
<dd><p><var class="var">kx_algorithm</var>: is a Key exchange algorithm
</p>
<p><var class="var">cipher_algorithm</var>: is a cipher algorithm
</p>
<p><var class="var">mac_algorithm</var>: is a MAC algorithm
</p>
<p>This function returns the ciphersuite name under TLS1.2 or earlier
versions when provided with individual algorithms. The full cipher suite
name must be prepended by TLS or SSL depending of the protocol in use.
</p>
<p>To get a description of the current ciphersuite across versions, it
is recommended to use <code class="code">gnutls_session_get_desc()</code> .
</p>
<p><strong class="strong">Returns:</strong> a string that contains the name of a TLS cipher suite,
specified by the given algorithms, or <code class="code">NULL</code> .
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcipher_005fsuite_005finfo-1"><span>gnutls_cipher_suite_info<a class="copiable-link" href="#gnutls_005fcipher_005fsuite_005finfo-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcipher_005fsuite_005finfo"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcipher_005fsuite_005finfo"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_cipher_suite_info</strong> <code class="def-code-arguments">(size_t <var class="var">idx</var>, unsigned char * <var class="var">cs_id</var>, gnutls_kx_algorithm_t * <var class="var">kx</var>, gnutls_cipher_algorithm_t * <var class="var">cipher</var>, gnutls_mac_algorithm_t * <var class="var">mac</var>, gnutls_protocol_t * <var class="var">min_version</var>)</code><a class="copiable-link" href="#index-gnutls_005fcipher_005fsuite_005finfo"> &para;</a></span></dt>
<dd><p><var class="var">idx</var>: index of cipher suite to get information about, starts on 0.
</p>
<p><var class="var">cs_id</var>: output buffer with room for 2 bytes, indicating cipher suite value
</p>
<p><var class="var">kx</var>: output variable indicating key exchange algorithm, or <code class="code">NULL</code> .
</p>
<p><var class="var">cipher</var>: output variable indicating cipher, or <code class="code">NULL</code> .
</p>
<p><var class="var">mac</var>: output variable indicating MAC algorithm, or <code class="code">NULL</code> .
</p>
<p><var class="var">min_version</var>: output variable indicating TLS protocol version, or <code class="code">NULL</code> .
</p>
<p>Get information about supported cipher suites.  Use the function
iteratively to get information about all supported cipher suites.
Call with idx=0 to get information about first cipher suite, then
idx=1 and so on until the function returns NULL.
</p>
<p><strong class="strong">Returns:</strong> the name of  <code class="code">idx</code> cipher suite, and set the information
about the cipher suite in the output variables.  If  <code class="code">idx</code> is out of
bounds, <code class="code">NULL</code>  is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fciphersuite_005fget-1"><span>gnutls_ciphersuite_get<a class="copiable-link" href="#gnutls_005fciphersuite_005fget-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fciphersuite_005fget"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fciphersuite_005fget"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_ciphersuite_get</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fciphersuite_005fget"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>Get the canonical name of negotiated TLS ciphersuite.  The names
returned by this function match the IANA registry, with one
exception:
</p>
<p>TLS_DHE_DSS_RC4_128_SHA { 0x00, 0x66 }
</p>
<p>which is reserved for compatibility.
</p>
<p>To get a detailed description of the current ciphersuite, it is
recommended to use <code class="code">gnutls_session_get_desc()</code> .
</p>
<p><strong class="strong">Returns:</strong> a string that contains the canonical name of a TLS ciphersuite,
or <code class="code">NULL</code>  if the handshake is not completed.
</p>
<p><strong class="strong">Since:</strong> 3.7.4
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcompress_005fcertificate_005fget_005fselected_005fmethod-1"><span>gnutls_compress_certificate_get_selected_method<a class="copiable-link" href="#gnutls_005fcompress_005fcertificate_005fget_005fselected_005fmethod-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcompress_005fcertificate_005fget_005fselected_005fmethod"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcompress_005fcertificate_005fget_005fselected_005fmethod"><span class="category-def">Function: </span><span><code class="def-type">gnutls_compression_method_t</code> <strong class="def-name">gnutls_compress_certificate_get_selected_method</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fcompress_005fcertificate_005fget_005fselected_005fmethod"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>This function returns the certificate compression method that has been
selected to compress the certificate before sending it to the peer.
The selection is done based on the local list of supported compression
methods and the peer&rsquo;s requested compression methods.
</p>
<p><strong class="strong">Returns:</strong> selected certificate compression method.
</p>
<p>Since 3.7.4
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcompress_005fcertificate_005fset_005fmethods-1"><span>gnutls_compress_certificate_set_methods<a class="copiable-link" href="#gnutls_005fcompress_005fcertificate_005fset_005fmethods-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcompress_005fcertificate_005fset_005fmethods"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcompress_005fcertificate_005fset_005fmethods"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_compress_certificate_set_methods</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, const gnutls_compression_method_t * <var class="var">methods</var>, size_t <var class="var">methods_len</var>)</code><a class="copiable-link" href="#index-gnutls_005fcompress_005fcertificate_005fset_005fmethods"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">methods</var>: is a list of supported compression methods.
</p>
<p><var class="var">methods_len</var>: number of compression methods in  <code class="code">methods</code> 
</p>
<p>This function sets the supported compression methods for certificate compression
for the given session. The list of supported compression methods will be used
for a) requesting the compression of peer&rsquo;s certificate and b) selecting the
method to compress the local certificate before sending it to the peer.
The order of compression methods inside the list does matter as the method
that appears earlier in the list will be preferred before the later ones.
Note that even if you set the list of supported compression methods, the
compression might not be used if the peer does not support any of your chosen
compression methods.
</p>
<p>The list of supported compression methods must meet the following criteria:
Argument  <code class="code">methods</code> must be an array of valid compression methods of type
<code class="code">gnutls_compression_method_t</code> . Argument  <code class="code">methods_len</code> must contain the number of
compression methods stored in the  <code class="code">methods</code> array and must be within range &lt;1, 127&gt;.
The length constraints are defined by <code class="code">MIN_COMPRESS_CERTIFICATE_METHODS</code> 
and <code class="code">MAX_COMPRESS_CERTIFICATE_METHODS</code>  macros located in the header file
compress_certificate.h.
</p>
<p>If either  <code class="code">methods</code> or  <code class="code">methods_len</code> is equal to 0, current list of supported
compression methods will be unset.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p>
<p>Since 3.7.4
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcredentials_005fclear-1"><span>gnutls_credentials_clear<a class="copiable-link" href="#gnutls_005fcredentials_005fclear-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcredentials_005fclear"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcredentials_005fclear"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_credentials_clear</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fcredentials_005fclear"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>Clears all the credentials previously set in this session.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcredentials_005fget-1"><span>gnutls_credentials_get<a class="copiable-link" href="#gnutls_005fcredentials_005fget-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcredentials_005fget"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcredentials_005fget"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_credentials_get</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_credentials_type_t <var class="var">type</var>, void ** <var class="var">cred</var>)</code><a class="copiable-link" href="#index-gnutls_005fcredentials_005fget"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">type</var>: is the type of the credentials to return
</p>
<p><var class="var">cred</var>: will contain the credentials.
</p>
<p>Returns the previously provided credentials structures.
</p>
<p>For <code class="code">GNUTLS_CRD_ANON</code> ,  <code class="code">cred</code> will be
<code class="code">gnutls_anon_client_credentials_t</code>  in case of a client.  In case of
a server it should be <code class="code">gnutls_anon_server_credentials_t</code> .
</p>
<p>For <code class="code">GNUTLS_CRD_SRP</code> ,  <code class="code">cred</code> will be <code class="code">gnutls_srp_client_credentials_t</code> 
in case of a client, and <code class="code">gnutls_srp_server_credentials_t</code> , in case
of a server.
</p>
<p>For <code class="code">GNUTLS_CRD_PSK</code> ,  <code class="code">cred</code> will be <code class="code">gnutls_psk_client_credentials_t</code> 
in case of a client, and <code class="code">gnutls_psk_server_credentials_t</code> , in case
of a server.
</p>
<p>For <code class="code">GNUTLS_CRD_CERTIFICATE</code> ,  <code class="code">cred</code> will be
<code class="code">gnutls_certificate_credentials_t</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned.
</p>
<p><strong class="strong">Since:</strong> 3.3.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcredentials_005fset-1"><span>gnutls_credentials_set<a class="copiable-link" href="#gnutls_005fcredentials_005fset-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcredentials_005fset"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcredentials_005fset-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_credentials_set</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_credentials_type_t <var class="var">type</var>, void * <var class="var">cred</var>)</code><a class="copiable-link" href="#index-gnutls_005fcredentials_005fset-1"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">type</var>: is the type of the credentials
</p>
<p><var class="var">cred</var>: the credentials to set
</p>
<p>Sets the needed credentials for the specified type.  E.g. username,
password - or public and private keys etc.  The  <code class="code">cred</code> parameter is
a structure that depends on the specified  <code class="code">type</code> and on the current
session (client or server). Only a single  <code class="code">cred</code> may be set for
each different  <code class="code">type</code> , subsequent calls with the same  <code class="code">type</code> will
replace the previously set credentials.
</p>
<p>In order to minimize memory usage, and share credentials between
several threads gnutls keeps a pointer to  <code class="code">cred</code> , and not the whole
cred structure.  Thus you will have to keep the structure allocated
until you call <code class="code">gnutls_deinit()</code> , or a future call of
<code class="code">gnutls_credentials_set()</code>  with the same  <code class="code">type</code> replaces the  <code class="code">cred</code> structure.
</p>
<p>For <code class="code">GNUTLS_CRD_ANON</code> ,  <code class="code">cred</code> should be
<code class="code">gnutls_anon_client_credentials_t</code>  in case of a client.  In case of
a server it should be <code class="code">gnutls_anon_server_credentials_t</code> .
</p>
<p>For <code class="code">GNUTLS_CRD_SRP</code> ,  <code class="code">cred</code> should be <code class="code">gnutls_srp_client_credentials_t</code> 
in case of a client, and <code class="code">gnutls_srp_server_credentials_t</code> , in case
of a server.
</p>
<p>For <code class="code">GNUTLS_CRD_CERTIFICATE</code> ,  <code class="code">cred</code> should be
<code class="code">gnutls_certificate_credentials_t</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdb_005fcheck_005fentry-1"><span>gnutls_db_check_entry<a class="copiable-link" href="#gnutls_005fdb_005fcheck_005fentry-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdb_005fcheck_005fentry"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdb_005fcheck_005fentry"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_db_check_entry</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_datum_t <var class="var">session_entry</var>)</code><a class="copiable-link" href="#index-gnutls_005fdb_005fcheck_005fentry"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">session_entry</var>: is the session data (not key)
</p>
<p>This function has no effect. 
</p>
<p><strong class="strong">Returns:</strong> Returns <code class="code">GNUTLS_E_EXPIRED</code> , if the database entry has
expired or 0 otherwise.
</p>
<p><strong class="strong">Deprecated:</strong> This function is deprecated.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdb_005fcheck_005fentry_005fexpire_005ftime-1"><span>gnutls_db_check_entry_expire_time<a class="copiable-link" href="#gnutls_005fdb_005fcheck_005fentry_005fexpire_005ftime-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdb_005fcheck_005fentry_005fexpire_005ftime"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdb_005fcheck_005fentry_005fexpire_005ftime"><span class="category-def">Function: </span><span><code class="def-type">time_t</code> <strong class="def-name">gnutls_db_check_entry_expire_time</strong> <code class="def-code-arguments">(gnutls_datum_t * <var class="var">entry</var>)</code><a class="copiable-link" href="#index-gnutls_005fdb_005fcheck_005fentry_005fexpire_005ftime"> &para;</a></span></dt>
<dd><p><var class="var">entry</var>: is a pointer to a <code class="code">gnutls_datum_t</code>  type.
</p>
<p>This function returns the time that this entry will expire.
It can be used for database entry expiration.
</p>
<p><strong class="strong">Returns:</strong> The time this entry will expire, or zero on error.
</p>
<p><strong class="strong">Since:</strong> 3.6.5
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdb_005fcheck_005fentry_005ftime-1"><span>gnutls_db_check_entry_time<a class="copiable-link" href="#gnutls_005fdb_005fcheck_005fentry_005ftime-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdb_005fcheck_005fentry_005ftime"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdb_005fcheck_005fentry_005ftime"><span class="category-def">Function: </span><span><code class="def-type">time_t</code> <strong class="def-name">gnutls_db_check_entry_time</strong> <code class="def-code-arguments">(gnutls_datum_t * <var class="var">entry</var>)</code><a class="copiable-link" href="#index-gnutls_005fdb_005fcheck_005fentry_005ftime"> &para;</a></span></dt>
<dd><p><var class="var">entry</var>: is a pointer to a <code class="code">gnutls_datum_t</code>  type.
</p>
<p>This function returns the time that this entry was active.
It can be used for database entry expiration.
</p>
<p><strong class="strong">Returns:</strong> The time this entry was created, or zero on error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdb_005fget_005fdefault_005fcache_005fexpiration-1"><span>gnutls_db_get_default_cache_expiration<a class="copiable-link" href="#gnutls_005fdb_005fget_005fdefault_005fcache_005fexpiration-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdb_005fget_005fdefault_005fcache_005fexpiration"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdb_005fget_005fdefault_005fcache_005fexpiration"><span class="category-def">Function: </span><span><code class="def-type">unsigned</code> <strong class="def-name">gnutls_db_get_default_cache_expiration</strong> <code class="def-code-arguments">( <var class="var">void</var>)</code><a class="copiable-link" href="#index-gnutls_005fdb_005fget_005fdefault_005fcache_005fexpiration"> &para;</a></span></dt>
<dd>
<p>Returns the expiration time (in seconds) of stored sessions for resumption. 
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdb_005fget_005fptr-1"><span>gnutls_db_get_ptr<a class="copiable-link" href="#gnutls_005fdb_005fget_005fptr-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdb_005fget_005fptr"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdb_005fget_005fptr"><span class="category-def">Function: </span><span><code class="def-type">void *</code> <strong class="def-name">gnutls_db_get_ptr</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fdb_005fget_005fptr"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>Get db function pointer.
</p>
<p><strong class="strong">Returns:</strong> the pointer that will be sent to db store, retrieve and
delete functions, as the first argument.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdb_005fremove_005fsession-1"><span>gnutls_db_remove_session<a class="copiable-link" href="#gnutls_005fdb_005fremove_005fsession-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdb_005fremove_005fsession"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdb_005fremove_005fsession"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_db_remove_session</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fdb_005fremove_005fsession"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>This function will remove the current session data from the
session database.  This will prevent future handshakes reusing
these session data.  This function should be called if a session
was terminated abnormally, and before <code class="code">gnutls_deinit()</code>  is called.
</p>
<p>Normally <code class="code">gnutls_deinit()</code>  will remove abnormally terminated
sessions.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdb_005fset_005fcache_005fexpiration-1"><span>gnutls_db_set_cache_expiration<a class="copiable-link" href="#gnutls_005fdb_005fset_005fcache_005fexpiration-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdb_005fset_005fcache_005fexpiration"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdb_005fset_005fcache_005fexpiration"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_db_set_cache_expiration</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, int <var class="var">seconds</var>)</code><a class="copiable-link" href="#index-gnutls_005fdb_005fset_005fcache_005fexpiration"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">seconds</var>: is the number of seconds.
</p>
<p>Set the expiration time for resumed sessions. The default is 21600
(6 hours) at the time of writing.
</p>
<p>The maximum value that can be set using this function is 604800
(7 days).
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdb_005fset_005fptr-1"><span>gnutls_db_set_ptr<a class="copiable-link" href="#gnutls_005fdb_005fset_005fptr-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdb_005fset_005fptr"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdb_005fset_005fptr"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_db_set_ptr</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, void * <var class="var">ptr</var>)</code><a class="copiable-link" href="#index-gnutls_005fdb_005fset_005fptr"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">ptr</var>: is the pointer
</p>
<p>Sets the pointer that will be provided to db store, retrieve and
delete functions, as the first argument.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdb_005fset_005fremove_005ffunction-1"><span>gnutls_db_set_remove_function<a class="copiable-link" href="#gnutls_005fdb_005fset_005fremove_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdb_005fset_005fremove_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdb_005fset_005fremove_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_db_set_remove_function</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_db_remove_func <var class="var">rem_func</var>)</code><a class="copiable-link" href="#index-gnutls_005fdb_005fset_005fremove_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">rem_func</var>: is the function.
</p>
<p>Sets the function that will be used to remove data from the
resumed sessions database. This function must return 0 on success.
</p>
<p>The first argument to  <code class="code">rem_func</code> will be null unless
<code class="code">gnutls_db_set_ptr()</code>  has been called.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdb_005fset_005fretrieve_005ffunction-1"><span>gnutls_db_set_retrieve_function<a class="copiable-link" href="#gnutls_005fdb_005fset_005fretrieve_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdb_005fset_005fretrieve_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdb_005fset_005fretrieve_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_db_set_retrieve_function</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_db_retr_func <var class="var">retr_func</var>)</code><a class="copiable-link" href="#index-gnutls_005fdb_005fset_005fretrieve_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">retr_func</var>: is the function.
</p>
<p>Sets the function that will be used to retrieve data from the
resumed sessions database.  This function must return a
gnutls_datum_t containing the data on success, or a gnutls_datum_t
containing null and 0 on failure.
</p>
<p>The datum&rsquo;s data must be allocated using the function
<code class="code">gnutls_malloc()</code> .
</p>
<p>The first argument to  <code class="code">retr_func</code> will be null unless
<code class="code">gnutls_db_set_ptr()</code>  has been called.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdb_005fset_005fstore_005ffunction-1"><span>gnutls_db_set_store_function<a class="copiable-link" href="#gnutls_005fdb_005fset_005fstore_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdb_005fset_005fstore_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdb_005fset_005fstore_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_db_set_store_function</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_db_store_func <var class="var">store_func</var>)</code><a class="copiable-link" href="#index-gnutls_005fdb_005fset_005fstore_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">store_func</var>: is the function
</p>
<p>Sets the function that will be used to store data in the resumed
sessions database. This function must return 0 on success.
</p>
<p>The first argument to  <code class="code">store_func</code> will be null unless
<code class="code">gnutls_db_set_ptr()</code>  has been called.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdeinit-1"><span>gnutls_deinit<a class="copiable-link" href="#gnutls_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdeinit-1"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_deinit</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fdeinit-1"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>This function clears all buffers associated with the  <code class="code">session</code> .
This function will also remove session data from the session
database if the session was terminated abnormally.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdh_005fget_005fgroup-1"><span>gnutls_dh_get_group<a class="copiable-link" href="#gnutls_005fdh_005fget_005fgroup-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdh_005fget_005fgroup"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdh_005fget_005fgroup"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_dh_get_group</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_datum_t * <var class="var">raw_gen</var>, gnutls_datum_t * <var class="var">raw_prime</var>)</code><a class="copiable-link" href="#index-gnutls_005fdh_005fget_005fgroup"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a gnutls session
</p>
<p><var class="var">raw_gen</var>: will hold the generator.
</p>
<p><var class="var">raw_prime</var>: will hold the prime.
</p>
<p>This function will return the group parameters used in the last
Diffie-Hellman key exchange with the peer.  These are the prime and
the generator used.  This function should be used for both
anonymous and ephemeral Diffie-Hellman.  The output parameters must
be freed with <code class="code">gnutls_free()</code> .
</p>
<p>Note, that the prime and generator are exported as non-negative
integers and may include a leading zero byte.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise
an error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdh_005fget_005fpeers_005fpublic_005fbits-1"><span>gnutls_dh_get_peers_public_bits<a class="copiable-link" href="#gnutls_005fdh_005fget_005fpeers_005fpublic_005fbits-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdh_005fget_005fpeers_005fpublic_005fbits"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdh_005fget_005fpeers_005fpublic_005fbits"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_dh_get_peers_public_bits</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fdh_005fget_005fpeers_005fpublic_005fbits"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a gnutls session
</p>
<p>Get the Diffie-Hellman public key bit size.  Can be used for both
anonymous and ephemeral Diffie-Hellman.
</p>
<p><strong class="strong">Returns:</strong> The public key bit size used in the last Diffie-Hellman
key exchange with the peer, or a negative error code in case of error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdh_005fget_005fprime_005fbits-1"><span>gnutls_dh_get_prime_bits<a class="copiable-link" href="#gnutls_005fdh_005fget_005fprime_005fbits-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdh_005fget_005fprime_005fbits"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdh_005fget_005fprime_005fbits"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_dh_get_prime_bits</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fdh_005fget_005fprime_005fbits"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a gnutls session
</p>
<p>This function will return the bits of the prime used in the last
Diffie-Hellman key exchange with the peer.  Should be used for both
anonymous and ephemeral Diffie-Hellman.  Note that some ciphers,
like RSA and DSA without DHE, do not use a Diffie-Hellman key
exchange, and then this function will return 0.
</p>
<p><strong class="strong">Returns:</strong> The Diffie-Hellman bit strength is returned, or 0 if no
Diffie-Hellman key exchange was done, or a negative error code on
failure.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdh_005fget_005fpubkey-1"><span>gnutls_dh_get_pubkey<a class="copiable-link" href="#gnutls_005fdh_005fget_005fpubkey-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdh_005fget_005fpubkey"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdh_005fget_005fpubkey"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_dh_get_pubkey</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_datum_t * <var class="var">raw_key</var>)</code><a class="copiable-link" href="#index-gnutls_005fdh_005fget_005fpubkey"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a gnutls session
</p>
<p><var class="var">raw_key</var>: will hold the public key.
</p>
<p>This function will return the peer&rsquo;s public key used in the last
Diffie-Hellman key exchange.  This function should be used for both
anonymous and ephemeral Diffie-Hellman.  The output parameters must
be freed with <code class="code">gnutls_free()</code> .
</p>
<p>Note, that public key is exported as non-negative
integer and may include a leading zero byte.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise
an error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdh_005fget_005fsecret_005fbits-1"><span>gnutls_dh_get_secret_bits<a class="copiable-link" href="#gnutls_005fdh_005fget_005fsecret_005fbits-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdh_005fget_005fsecret_005fbits"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdh_005fget_005fsecret_005fbits"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_dh_get_secret_bits</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fdh_005fget_005fsecret_005fbits"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a gnutls session
</p>
<p>This function will return the bits used in the last Diffie-Hellman
key exchange with the peer.  Should be used for both anonymous and
ephemeral Diffie-Hellman.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise
an error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdh_005fparams_005fcpy-1"><span>gnutls_dh_params_cpy<a class="copiable-link" href="#gnutls_005fdh_005fparams_005fcpy-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdh_005fparams_005fcpy"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdh_005fparams_005fcpy"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_dh_params_cpy</strong> <code class="def-code-arguments">(gnutls_dh_params_t <var class="var">dst</var>, gnutls_dh_params_t <var class="var">src</var>)</code><a class="copiable-link" href="#index-gnutls_005fdh_005fparams_005fcpy"> &para;</a></span></dt>
<dd><p><var class="var">dst</var>: Is the destination parameters, which should be initialized.
</p>
<p><var class="var">src</var>: Is the source parameters
</p>
<p>This function will copy the DH parameters structure from source
to destination. The destination should be already initialized.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdh_005fparams_005fdeinit-1"><span>gnutls_dh_params_deinit<a class="copiable-link" href="#gnutls_005fdh_005fparams_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdh_005fparams_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdh_005fparams_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_dh_params_deinit</strong> <code class="def-code-arguments">(gnutls_dh_params_t <var class="var">dh_params</var>)</code><a class="copiable-link" href="#index-gnutls_005fdh_005fparams_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">dh_params</var>: The parameters
</p>
<p>This function will deinitialize the DH parameters type.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdh_005fparams_005fexport2_005fpkcs3-1"><span>gnutls_dh_params_export2_pkcs3<a class="copiable-link" href="#gnutls_005fdh_005fparams_005fexport2_005fpkcs3-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdh_005fparams_005fexport2_005fpkcs3"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdh_005fparams_005fexport2_005fpkcs3"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_dh_params_export2_pkcs3</strong> <code class="def-code-arguments">(gnutls_dh_params_t <var class="var">params</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, gnutls_datum_t * <var class="var">out</var>)</code><a class="copiable-link" href="#index-gnutls_005fdh_005fparams_005fexport2_005fpkcs3"> &para;</a></span></dt>
<dd><p><var class="var">params</var>: Holds the DH parameters
</p>
<p><var class="var">format</var>: the format of output params. One of PEM or DER.
</p>
<p><var class="var">out</var>: will contain a PKCS3 DHParams structure PEM or DER encoded
</p>
<p>This function will export the given dh parameters to a PKCS3
DHParams structure. This is the format generated by &quot;openssl dhparam&quot; tool.
The data in  <code class="code">out</code> will be allocated using <code class="code">gnutls_malloc()</code> .
</p>
<p>If the structure is PEM encoded, it will have a header
of &quot;BEGIN DH PARAMETERS&quot;.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned.
</p>
<p><strong class="strong">Since:</strong> 3.1.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdh_005fparams_005fexport_005fpkcs3-1"><span>gnutls_dh_params_export_pkcs3<a class="copiable-link" href="#gnutls_005fdh_005fparams_005fexport_005fpkcs3-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdh_005fparams_005fexport_005fpkcs3"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdh_005fparams_005fexport_005fpkcs3"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_dh_params_export_pkcs3</strong> <code class="def-code-arguments">(gnutls_dh_params_t <var class="var">params</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, unsigned char * <var class="var">params_data</var>, size_t * <var class="var">params_data_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fdh_005fparams_005fexport_005fpkcs3"> &para;</a></span></dt>
<dd><p><var class="var">params</var>: Holds the DH parameters
</p>
<p><var class="var">format</var>: the format of output params. One of PEM or DER.
</p>
<p><var class="var">params_data</var>: will contain a PKCS3 DHParams structure PEM or DER encoded
</p>
<p><var class="var">params_data_size</var>: holds the size of params_data (and will be replaced by the actual size of parameters)
</p>
<p>This function will export the given dh parameters to a PKCS3
DHParams structure. This is the format generated by &quot;openssl dhparam&quot; tool.
If the buffer provided is not long enough to hold the output, then
GNUTLS_E_SHORT_MEMORY_BUFFER will be returned.
</p>
<p>If the structure is PEM encoded, it will have a header
of &quot;BEGIN DH PARAMETERS&quot;.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdh_005fparams_005fexport_005fraw-1"><span>gnutls_dh_params_export_raw<a class="copiable-link" href="#gnutls_005fdh_005fparams_005fexport_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdh_005fparams_005fexport_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdh_005fparams_005fexport_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_dh_params_export_raw</strong> <code class="def-code-arguments">(gnutls_dh_params_t <var class="var">params</var>, gnutls_datum_t * <var class="var">prime</var>, gnutls_datum_t * <var class="var">generator</var>, unsigned int * <var class="var">bits</var>)</code><a class="copiable-link" href="#index-gnutls_005fdh_005fparams_005fexport_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">params</var>: Holds the DH parameters
</p>
<p><var class="var">prime</var>: will hold the new prime
</p>
<p><var class="var">generator</var>: will hold the new generator
</p>
<p><var class="var">bits</var>: if non null will hold the secret key&rsquo;s number of bits
</p>
<p>This function will export the pair of prime and generator for use
in the Diffie-Hellman key exchange.  The new parameters will be
allocated using <code class="code">gnutls_malloc()</code>  and will be stored in the
appropriate datum.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdh_005fparams_005fgenerate2-1"><span>gnutls_dh_params_generate2<a class="copiable-link" href="#gnutls_005fdh_005fparams_005fgenerate2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdh_005fparams_005fgenerate2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdh_005fparams_005fgenerate2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_dh_params_generate2</strong> <code class="def-code-arguments">(gnutls_dh_params_t <var class="var">dparams</var>, unsigned int <var class="var">bits</var>)</code><a class="copiable-link" href="#index-gnutls_005fdh_005fparams_005fgenerate2"> &para;</a></span></dt>
<dd><p><var class="var">dparams</var>: The parameters
</p>
<p><var class="var">bits</var>: is the prime&rsquo;s number of bits
</p>
<p>This function will generate a new pair of prime and generator for use in
the Diffie-Hellman key exchange. This may take long time.
</p>
<p>It is recommended not to set the number of bits directly, but 
use <code class="code">gnutls_sec_param_to_pk_bits()</code>  instead.
Also note that the DH parameters are only useful to servers.
Since clients use the parameters sent by the server, it&rsquo;s of
no use to call this in client side.
</p>
<p>The parameters generated are of the DSA form. It also is possible
to generate provable parameters (following the Shawe-Taylor
algorithm), using <code class="code">gnutls_x509_privkey_generate2()</code>  with DSA option
and the <code class="code">GNUTLS_PRIVKEY_FLAG_PROVABLE</code>  flag set. These can the
be imported with <code class="code">gnutls_dh_params_import_dsa()</code> .
</p>
<p>It is no longer recommended for applications to generate parameters.
See the &quot;Parameter generation&quot; section in the manual.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdh_005fparams_005fimport_005fdsa-1"><span>gnutls_dh_params_import_dsa<a class="copiable-link" href="#gnutls_005fdh_005fparams_005fimport_005fdsa-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdh_005fparams_005fimport_005fdsa"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdh_005fparams_005fimport_005fdsa"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_dh_params_import_dsa</strong> <code class="def-code-arguments">(gnutls_dh_params_t <var class="var">dh_params</var>, gnutls_x509_privkey_t <var class="var">key</var>)</code><a class="copiable-link" href="#index-gnutls_005fdh_005fparams_005fimport_005fdsa"> &para;</a></span></dt>
<dd><p><var class="var">dh_params</var>: The parameters
</p>
<p><var class="var">key</var>: holds a DSA private key
</p>
<p>This function will import the prime and generator of the DSA key for use 
in the Diffie-Hellman key exchange.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdh_005fparams_005fimport_005fpkcs3-1"><span>gnutls_dh_params_import_pkcs3<a class="copiable-link" href="#gnutls_005fdh_005fparams_005fimport_005fpkcs3-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdh_005fparams_005fimport_005fpkcs3"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdh_005fparams_005fimport_005fpkcs3"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_dh_params_import_pkcs3</strong> <code class="def-code-arguments">(gnutls_dh_params_t <var class="var">params</var>, const gnutls_datum_t * <var class="var">pkcs3_params</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>)</code><a class="copiable-link" href="#index-gnutls_005fdh_005fparams_005fimport_005fpkcs3"> &para;</a></span></dt>
<dd><p><var class="var">params</var>: The parameters
</p>
<p><var class="var">pkcs3_params</var>: should contain a PKCS3 DHParams structure PEM or DER encoded
</p>
<p><var class="var">format</var>: the format of params. PEM or DER.
</p>
<p>This function will extract the DHParams found in a PKCS3 formatted
structure. This is the format generated by &quot;openssl dhparam&quot; tool.
</p>
<p>If the structure is PEM encoded, it should have a header
of &quot;BEGIN DH PARAMETERS&quot;.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdh_005fparams_005fimport_005fraw-1"><span>gnutls_dh_params_import_raw<a class="copiable-link" href="#gnutls_005fdh_005fparams_005fimport_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdh_005fparams_005fimport_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdh_005fparams_005fimport_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_dh_params_import_raw</strong> <code class="def-code-arguments">(gnutls_dh_params_t <var class="var">dh_params</var>, const gnutls_datum_t * <var class="var">prime</var>, const gnutls_datum_t * <var class="var">generator</var>)</code><a class="copiable-link" href="#index-gnutls_005fdh_005fparams_005fimport_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">dh_params</var>: The parameters
</p>
<p><var class="var">prime</var>: holds the new prime
</p>
<p><var class="var">generator</var>: holds the new generator
</p>
<p>This function will replace the pair of prime and generator for use
in the Diffie-Hellman key exchange.  The new parameters should be
stored in the appropriate gnutls_datum.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdh_005fparams_005fimport_005fraw2-1"><span>gnutls_dh_params_import_raw2<a class="copiable-link" href="#gnutls_005fdh_005fparams_005fimport_005fraw2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdh_005fparams_005fimport_005fraw2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdh_005fparams_005fimport_005fraw2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_dh_params_import_raw2</strong> <code class="def-code-arguments">(gnutls_dh_params_t <var class="var">dh_params</var>, const gnutls_datum_t * <var class="var">prime</var>, const gnutls_datum_t * <var class="var">generator</var>, unsigned <var class="var">key_bits</var>)</code><a class="copiable-link" href="#index-gnutls_005fdh_005fparams_005fimport_005fraw2"> &para;</a></span></dt>
<dd><p><var class="var">dh_params</var>: The parameters
</p>
<p><var class="var">prime</var>: holds the new prime
</p>
<p><var class="var">generator</var>: holds the new generator
</p>
<p><var class="var">key_bits</var>: the private key bits (set to zero when unknown)
</p>
<p>This function will replace the pair of prime and generator for use
in the Diffie-Hellman key exchange.  The new parameters should be
stored in the appropriate gnutls_datum.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdh_005fparams_005fimport_005fraw3-1"><span>gnutls_dh_params_import_raw3<a class="copiable-link" href="#gnutls_005fdh_005fparams_005fimport_005fraw3-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdh_005fparams_005fimport_005fraw3"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdh_005fparams_005fimport_005fraw3"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_dh_params_import_raw3</strong> <code class="def-code-arguments">(gnutls_dh_params_t <var class="var">dh_params</var>, const gnutls_datum_t * <var class="var">prime</var>, const gnutls_datum_t * <var class="var">q</var>, const gnutls_datum_t * <var class="var">generator</var>)</code><a class="copiable-link" href="#index-gnutls_005fdh_005fparams_005fimport_005fraw3"> &para;</a></span></dt>
<dd><p><var class="var">dh_params</var>: The parameters
</p>
<p><var class="var">prime</var>: holds the new prime
</p>
<p><var class="var">q</var>: holds the subgroup if available, otherwise NULL
</p>
<p><var class="var">generator</var>: holds the new generator
</p>
<p>This function will replace the pair of prime and generator for use
in the Diffie-Hellman key exchange.  The new parameters should be
stored in the appropriate gnutls_datum.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdh_005fparams_005finit-1"><span>gnutls_dh_params_init<a class="copiable-link" href="#gnutls_005fdh_005fparams_005finit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdh_005fparams_005finit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdh_005fparams_005finit"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_dh_params_init</strong> <code class="def-code-arguments">(gnutls_dh_params_t * <var class="var">dh_params</var>)</code><a class="copiable-link" href="#index-gnutls_005fdh_005fparams_005finit"> &para;</a></span></dt>
<dd><p><var class="var">dh_params</var>: The parameters
</p>
<p>This function will initialize the DH parameters type.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdh_005fset_005fprime_005fbits-1"><span>gnutls_dh_set_prime_bits<a class="copiable-link" href="#gnutls_005fdh_005fset_005fprime_005fbits-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdh_005fset_005fprime_005fbits"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdh_005fset_005fprime_005fbits"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_dh_set_prime_bits</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, unsigned int <var class="var">bits</var>)</code><a class="copiable-link" href="#index-gnutls_005fdh_005fset_005fprime_005fbits"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">bits</var>: is the number of bits
</p>
<p>This function sets the number of bits, for use in a Diffie-Hellman
key exchange.  This is used both in DH ephemeral and DH anonymous
cipher suites.  This will set the minimum size of the prime that
will be used for the handshake.
</p>
<p>In the client side it sets the minimum accepted number of bits.  If
a server sends a prime with less bits than that
<code class="code">GNUTLS_E_DH_PRIME_UNACCEPTABLE</code>  will be returned by the handshake.
</p>
<p>Note that this function will warn via the audit log for value that
are believed to be weak.
</p>
<p>The function has no effect in server side.
</p>
<p>Note that since 3.1.7 this function is deprecated. The minimum
number of bits is set by the priority string level.
Also this function must be called after <code class="code">gnutls_priority_set_direct()</code> 
or the set value may be overridden by the selected priority options.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdigest_005fget_005fid-1"><span>gnutls_digest_get_id<a class="copiable-link" href="#gnutls_005fdigest_005fget_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdigest_005fget_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdigest_005fget_005fid"><span class="category-def">Function: </span><span><code class="def-type">gnutls_digest_algorithm_t</code> <strong class="def-name">gnutls_digest_get_id</strong> <code class="def-code-arguments">(const char * <var class="var">name</var>)</code><a class="copiable-link" href="#index-gnutls_005fdigest_005fget_005fid"> &para;</a></span></dt>
<dd><p><var class="var">name</var>: is a digest algorithm name
</p>
<p>Convert a string to a <code class="code">gnutls_digest_algorithm_t</code>  value.  The names are
compared in a case insensitive way.
</p>
<p><strong class="strong">Returns:</strong> a <code class="code">gnutls_digest_algorithm_t</code>  id of the specified MAC
algorithm string, or <code class="code">GNUTLS_DIG_UNKNOWN</code>  on failure.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdigest_005fget_005fname-1"><span>gnutls_digest_get_name<a class="copiable-link" href="#gnutls_005fdigest_005fget_005fname-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdigest_005fget_005fname"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdigest_005fget_005fname"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_digest_get_name</strong> <code class="def-code-arguments">(gnutls_digest_algorithm_t <var class="var">algorithm</var>)</code><a class="copiable-link" href="#index-gnutls_005fdigest_005fget_005fname"> &para;</a></span></dt>
<dd><p><var class="var">algorithm</var>: is a digest algorithm
</p>
<p>Convert a <code class="code">gnutls_digest_algorithm_t</code>  value to a string.
</p>
<p><strong class="strong">Returns:</strong> a string that contains the name of the specified digest
algorithm, or <code class="code">NULL</code> .
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdigest_005fget_005foid-1"><span>gnutls_digest_get_oid<a class="copiable-link" href="#gnutls_005fdigest_005fget_005foid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdigest_005fget_005foid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdigest_005fget_005foid"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_digest_get_oid</strong> <code class="def-code-arguments">(gnutls_digest_algorithm_t <var class="var">algorithm</var>)</code><a class="copiable-link" href="#index-gnutls_005fdigest_005fget_005foid"> &para;</a></span></dt>
<dd><p><var class="var">algorithm</var>: is a digest algorithm
</p>
<p>Convert a <code class="code">gnutls_digest_algorithm_t</code>  value to its object identifier.
</p>
<p><strong class="strong">Returns:</strong> a string that contains the object identifier of the specified digest
algorithm, or <code class="code">NULL</code> .
</p>
<p><strong class="strong">Since:</strong> 3.4.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdigest_005flist-1"><span>gnutls_digest_list<a class="copiable-link" href="#gnutls_005fdigest_005flist-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdigest_005flist"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdigest_005flist"><span class="category-def">Function: </span><span><code class="def-type">const gnutls_digest_algorithm_t *</code> <strong class="def-name">gnutls_digest_list</strong> <code class="def-code-arguments">( <var class="var">void</var>)</code><a class="copiable-link" href="#index-gnutls_005fdigest_005flist"> &para;</a></span></dt>
<dd>
<p>Get a list of hash (digest) algorithms supported by GnuTLS.
</p>
<p>This function is not thread safe.
</p>
<p><strong class="strong">Returns:</strong> Return a (0)-terminated list of <code class="code">gnutls_digest_algorithm_t</code> 
integers indicating the available digests.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdigest_005fset_005fsecure-1"><span>gnutls_digest_set_secure<a class="copiable-link" href="#gnutls_005fdigest_005fset_005fsecure-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdigest_005fset_005fsecure"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdigest_005fset_005fsecure"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_digest_set_secure</strong> <code class="def-code-arguments">(gnutls_digest_algorithm_t <var class="var">dig</var>, unsigned int <var class="var">secure</var>)</code><a class="copiable-link" href="#index-gnutls_005fdigest_005fset_005fsecure"> &para;</a></span></dt>
<dd><p><var class="var">dig</var>: is a digest algorithm
</p>
<p><var class="var">secure</var>: whether to mark the digest algorithm secure
</p>
<p>Modify the previous system wide setting that marked  <code class="code">dig</code> as secure
or insecure. This only has effect when the algorithm is enabled
through the allowlisting mode in the configuration file, or when
the setting is modified with a prior call to this function.
</p>
<p><strong class="strong">Since:</strong> 3.7.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fearly_005fcipher_005fget-1"><span>gnutls_early_cipher_get<a class="copiable-link" href="#gnutls_005fearly_005fcipher_005fget-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fearly_005fcipher_005fget"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fearly_005fcipher_005fget"><span class="category-def">Function: </span><span><code class="def-type">gnutls_cipher_algorithm_t</code> <strong class="def-name">gnutls_early_cipher_get</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fearly_005fcipher_005fget"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>Get the cipher algorithm used for encrypting early data.
</p>
<p><strong class="strong">Returns:</strong> the cipher used for early data, a
<code class="code">gnutls_cipher_algorithm_t</code>  type.
</p>
<p><strong class="strong">Since:</strong> 3.7.2
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fearly_005fprf_005fhash_005fget-1"><span>gnutls_early_prf_hash_get<a class="copiable-link" href="#gnutls_005fearly_005fprf_005fhash_005fget-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fearly_005fprf_005fhash_005fget"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fearly_005fprf_005fhash_005fget"><span class="category-def">Function: </span><span><code class="def-type">gnutls_digest_algorithm_t</code> <strong class="def-name">gnutls_early_prf_hash_get</strong> <code class="def-code-arguments">(const gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fearly_005fprf_005fhash_005fget"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>Get the hash algorithm used as a PRF to derive keys for encrypting
early data in TLS 1.3.
</p>
<p><strong class="strong">Returns:</strong> the hash algorithm used for early data, a
<code class="code">gnutls_digest_algorithm_t</code>  value.
</p>
<p><strong class="strong">Since:</strong> 3.7.2
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fecc_005fcurve_005fget-1"><span>gnutls_ecc_curve_get<a class="copiable-link" href="#gnutls_005fecc_005fcurve_005fget-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fecc_005fcurve_005fget"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fecc_005fcurve_005fget"><span class="category-def">Function: </span><span><code class="def-type">gnutls_ecc_curve_t</code> <strong class="def-name">gnutls_ecc_curve_get</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fecc_005fcurve_005fget"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>Returns the currently used elliptic curve for key exchange. Only valid
when using an elliptic curve ciphersuite.
</p>
<p><strong class="strong">Returns:</strong> the currently used curve, a <code class="code">gnutls_ecc_curve_t</code> 
type.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fecc_005fcurve_005fget_005fid-1"><span>gnutls_ecc_curve_get_id<a class="copiable-link" href="#gnutls_005fecc_005fcurve_005fget_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fecc_005fcurve_005fget_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fecc_005fcurve_005fget_005fid"><span class="category-def">Function: </span><span><code class="def-type">gnutls_ecc_curve_t</code> <strong class="def-name">gnutls_ecc_curve_get_id</strong> <code class="def-code-arguments">(const char * <var class="var">name</var>)</code><a class="copiable-link" href="#index-gnutls_005fecc_005fcurve_005fget_005fid"> &para;</a></span></dt>
<dd><p><var class="var">name</var>: is a curve name
</p>
<p>The names are compared in a case insensitive way.
</p>
<p><strong class="strong">Returns:</strong> return a <code class="code">gnutls_ecc_curve_t</code>  value corresponding to
the specified curve, or <code class="code">GNUTLS_ECC_CURVE_INVALID</code>  on error.
</p>
<p><strong class="strong">Since:</strong> 3.4.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fecc_005fcurve_005fget_005fname-1"><span>gnutls_ecc_curve_get_name<a class="copiable-link" href="#gnutls_005fecc_005fcurve_005fget_005fname-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fecc_005fcurve_005fget_005fname"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fecc_005fcurve_005fget_005fname"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_ecc_curve_get_name</strong> <code class="def-code-arguments">(gnutls_ecc_curve_t <var class="var">curve</var>)</code><a class="copiable-link" href="#index-gnutls_005fecc_005fcurve_005fget_005fname"> &para;</a></span></dt>
<dd><p><var class="var">curve</var>: is an ECC curve
</p>
<p>Convert a <code class="code">gnutls_ecc_curve_t</code>  value to a string.
</p>
<p><strong class="strong">Returns:</strong> a string that contains the name of the specified
curve or <code class="code">NULL</code> .
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fecc_005fcurve_005fget_005foid-1"><span>gnutls_ecc_curve_get_oid<a class="copiable-link" href="#gnutls_005fecc_005fcurve_005fget_005foid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fecc_005fcurve_005fget_005foid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fecc_005fcurve_005fget_005foid"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_ecc_curve_get_oid</strong> <code class="def-code-arguments">(gnutls_ecc_curve_t <var class="var">curve</var>)</code><a class="copiable-link" href="#index-gnutls_005fecc_005fcurve_005fget_005foid"> &para;</a></span></dt>
<dd><p><var class="var">curve</var>: is an ECC curve
</p>
<p>Convert a <code class="code">gnutls_ecc_curve_t</code>  value to its object identifier.
</p>
<p><strong class="strong">Returns:</strong> a string that contains the OID of the specified
curve or <code class="code">NULL</code> .
</p>
<p><strong class="strong">Since:</strong> 3.4.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fecc_005fcurve_005fget_005fpk-1"><span>gnutls_ecc_curve_get_pk<a class="copiable-link" href="#gnutls_005fecc_005fcurve_005fget_005fpk-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fecc_005fcurve_005fget_005fpk"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fecc_005fcurve_005fget_005fpk"><span class="category-def">Function: </span><span><code class="def-type">gnutls_pk_algorithm_t</code> <strong class="def-name">gnutls_ecc_curve_get_pk</strong> <code class="def-code-arguments">(gnutls_ecc_curve_t <var class="var">curve</var>)</code><a class="copiable-link" href="#index-gnutls_005fecc_005fcurve_005fget_005fpk"> &para;</a></span></dt>
<dd><p><var class="var">curve</var>: is an ECC curve
</p>

<p><strong class="strong">Returns:</strong> the public key algorithm associated with the named curve or <code class="code">GNUTLS_PK_UNKNOWN</code> .
</p>
<p><strong class="strong">Since:</strong> 3.5.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fecc_005fcurve_005fget_005fsize-1"><span>gnutls_ecc_curve_get_size<a class="copiable-link" href="#gnutls_005fecc_005fcurve_005fget_005fsize-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fecc_005fcurve_005fget_005fsize"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fecc_005fcurve_005fget_005fsize"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ecc_curve_get_size</strong> <code class="def-code-arguments">(gnutls_ecc_curve_t <var class="var">curve</var>)</code><a class="copiable-link" href="#index-gnutls_005fecc_005fcurve_005fget_005fsize"> &para;</a></span></dt>
<dd><p><var class="var">curve</var>: is an ECC curve
</p>

<p><strong class="strong">Returns:</strong> the size in bytes of the curve or 0 on failure.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fecc_005fcurve_005flist-1"><span>gnutls_ecc_curve_list<a class="copiable-link" href="#gnutls_005fecc_005fcurve_005flist-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fecc_005fcurve_005flist"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fecc_005fcurve_005flist"><span class="category-def">Function: </span><span><code class="def-type">const gnutls_ecc_curve_t *</code> <strong class="def-name">gnutls_ecc_curve_list</strong> <code class="def-code-arguments">( <var class="var">void</var>)</code><a class="copiable-link" href="#index-gnutls_005fecc_005fcurve_005flist"> &para;</a></span></dt>
<dd>
<p>Get the list of supported elliptic curves.
</p>
<p>This function is not thread safe.
</p>
<p><strong class="strong">Returns:</strong> Return a (0)-terminated list of <code class="code">gnutls_ecc_curve_t</code> 
integers indicating the available curves.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fecc_005fcurve_005fset_005fenabled-1"><span>gnutls_ecc_curve_set_enabled<a class="copiable-link" href="#gnutls_005fecc_005fcurve_005fset_005fenabled-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fecc_005fcurve_005fset_005fenabled"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fecc_005fcurve_005fset_005fenabled"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ecc_curve_set_enabled</strong> <code class="def-code-arguments">(gnutls_ecc_curve_t <var class="var">curve</var>, unsigned int <var class="var">enabled</var>)</code><a class="copiable-link" href="#index-gnutls_005fecc_005fcurve_005fset_005fenabled"> &para;</a></span></dt>
<dd><p><var class="var">curve</var>: is an ECC curve
</p>
<p><var class="var">enabled</var>: whether to enable the curve
</p>
<p>Modify the previous system wide setting that marked  <code class="code">curve</code> as
enabled or disabled.  Calling this function is allowed
only if allowlisting mode is set in the configuration file,
and only if the system-wide TLS priority string
has not been initialized yet.
The intended usage is to provide applications with a way
to expressly deviate from the distribution or site defaults
inherited from the configuration file.
The modification is composable with further modifications
performed through the priority string mechanism.
</p>
<p>This function is not thread-safe and is intended to be called
in the main thread at the beginning of the process execution.
</p>
<p><strong class="strong">Returns:</strong> 0 on success or negative error code otherwise.
</p>
<p><strong class="strong">Since:</strong> 3.7.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005ferror_005fis_005ffatal-1"><span>gnutls_error_is_fatal<a class="copiable-link" href="#gnutls_005ferror_005fis_005ffatal-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005ferror_005fis_005ffatal"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ferror_005fis_005ffatal-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_error_is_fatal</strong> <code class="def-code-arguments">(int <var class="var">error</var>)</code><a class="copiable-link" href="#index-gnutls_005ferror_005fis_005ffatal-1"> &para;</a></span></dt>
<dd><p><var class="var">error</var>: is a GnuTLS error code, a negative error code
</p>
<p>If a GnuTLS function returns a negative error code you may feed that
value to this function to see if the error condition is fatal to
a TLS session (i.e., must be terminated).
</p>
<p>Note that you may also want to check the error code manually, since some
non-fatal errors to the protocol (such as a warning alert or
a rehandshake request) may be fatal for your program.
</p>
<p>This function is only useful if you are dealing with errors from
functions that relate to a TLS session (e.g., record layer or handshake
layer handling functions).
</p>
<p><strong class="strong">Returns:</strong> Non-zero value on fatal errors or zero on non-fatal.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005ferror_005fto_005falert-1"><span>gnutls_error_to_alert<a class="copiable-link" href="#gnutls_005ferror_005fto_005falert-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005ferror_005fto_005falert"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ferror_005fto_005falert-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_error_to_alert</strong> <code class="def-code-arguments">(int <var class="var">err</var>, int * <var class="var">level</var>)</code><a class="copiable-link" href="#index-gnutls_005ferror_005fto_005falert-1"> &para;</a></span></dt>
<dd><p><var class="var">err</var>: is a negative integer
</p>
<p><var class="var">level</var>: the alert level will be stored there
</p>
<p>Get an alert depending on the error code returned by a gnutls
function.  All alerts sent by this function should be considered
fatal.  The only exception is when  <code class="code">err</code> is <code class="code">GNUTLS_E_REHANDSHAKE</code> ,
where a warning alert should be sent to the peer indicating that no
renegotiation will be performed.
</p>
<p>If there is no mapping to a valid alert the alert to indicate
internal error (<code class="code">GNUTLS_A_INTERNAL_ERROR</code> ) is returned.
</p>
<p><strong class="strong">Returns:</strong> the alert code to use for a particular error code.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fest_005frecord_005foverhead_005fsize-1"><span>gnutls_est_record_overhead_size<a class="copiable-link" href="#gnutls_005fest_005frecord_005foverhead_005fsize-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fest_005frecord_005foverhead_005fsize"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fest_005frecord_005foverhead_005fsize"><span class="category-def">Function: </span><span><code class="def-type">size_t</code> <strong class="def-name">gnutls_est_record_overhead_size</strong> <code class="def-code-arguments">(gnutls_protocol_t <var class="var">version</var>, gnutls_cipher_algorithm_t <var class="var">cipher</var>, gnutls_mac_algorithm_t <var class="var">mac</var>, gnutls_compression_method_t <var class="var">comp</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fest_005frecord_005foverhead_005fsize"> &para;</a></span></dt>
<dd><p><var class="var">version</var>: is a <code class="code">gnutls_protocol_t</code>  value
</p>
<p><var class="var">cipher</var>: is a <code class="code">gnutls_cipher_algorithm_t</code>  value
</p>
<p><var class="var">mac</var>: is a <code class="code">gnutls_mac_algorithm_t</code>  value
</p>
<p><var class="var">comp</var>: is a <code class="code">gnutls_compression_method_t</code>  value (ignored)
</p>
<p><var class="var">flags</var>: must be zero
</p>
<p>This function will return the set size in bytes of the overhead
due to TLS (or DTLS) per record.
</p>
<p>Note that this function may provide inaccurate values when TLS
extensions that modify the record format are negotiated. In these
cases a more accurate value can be obtained using <code class="code">gnutls_record_overhead_size()</code>  
after a completed handshake.
</p>
<p><strong class="strong">Since:</strong> 3.2.2
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fext_005fget_005fcurrent_005fmsg-1"><span>gnutls_ext_get_current_msg<a class="copiable-link" href="#gnutls_005fext_005fget_005fcurrent_005fmsg-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fext_005fget_005fcurrent_005fmsg"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fext_005fget_005fcurrent_005fmsg"><span class="category-def">Function: </span><span><code class="def-type">unsigned</code> <strong class="def-name">gnutls_ext_get_current_msg</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fext_005fget_005fcurrent_005fmsg"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: a <code class="code">gnutls_session_t</code>  opaque pointer
</p>
<p>This function allows an extension handler to obtain the message
this extension is being called from. The returned value is a single
entry of the <code class="code">gnutls_ext_flags_t</code>  enumeration. That is, if an
extension was registered with the <code class="code">GNUTLS_EXT_FLAG_HRR</code>  and
<code class="code">GNUTLS_EXT_FLAG_EE</code>  flags, the value when called during parsing of the
encrypted extensions message will be <code class="code">GNUTLS_EXT_FLAG_EE</code> .
</p>
<p>If not called under an extension handler, its value is undefined.
</p>
<p><strong class="strong">Since:</strong> 3.6.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fext_005fget_005fdata-1"><span>gnutls_ext_get_data<a class="copiable-link" href="#gnutls_005fext_005fget_005fdata-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fext_005fget_005fdata"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fext_005fget_005fdata"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ext_get_data</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, unsigned <var class="var">tls_id</var>, gnutls_ext_priv_data_t * <var class="var">data</var>)</code><a class="copiable-link" href="#index-gnutls_005fext_005fget_005fdata"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: a <code class="code">gnutls_session_t</code>  opaque pointer
</p>
<p><var class="var">tls_id</var>: the numeric id of the extension
</p>
<p><var class="var">data</var>: a pointer to the private data to retrieve
</p>
<p>This function retrieves any data previously stored with <code class="code">gnutls_ext_set_data()</code> .
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fext_005fget_005fname-1"><span>gnutls_ext_get_name<a class="copiable-link" href="#gnutls_005fext_005fget_005fname-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fext_005fget_005fname"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fext_005fget_005fname"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_ext_get_name</strong> <code class="def-code-arguments">(unsigned int <var class="var">ext</var>)</code><a class="copiable-link" href="#index-gnutls_005fext_005fget_005fname"> &para;</a></span></dt>
<dd><p><var class="var">ext</var>: is a TLS extension numeric ID
</p>
<p>Convert a TLS extension numeric ID to a printable string.
</p>
<p><strong class="strong">Returns:</strong> a pointer to a string that contains the name of the
specified cipher, or <code class="code">NULL</code> .
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fext_005fget_005fname2-1"><span>gnutls_ext_get_name2<a class="copiable-link" href="#gnutls_005fext_005fget_005fname2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fext_005fget_005fname2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fext_005fget_005fname2"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_ext_get_name2</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, unsigned int <var class="var">tls_id</var>, gnutls_ext_parse_type_t <var class="var">parse_point</var>)</code><a class="copiable-link" href="#index-gnutls_005fext_005fget_005fname2"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: a <code class="code">gnutls_session_t</code>  opaque pointer
</p>
<p><var class="var">tls_id</var>: is a TLS extension numeric ID
</p>
<p><var class="var">parse_point</var>: the parse type of the extension
</p>
<p>Convert a TLS extension numeric ID to a printable string.
</p>
<p><strong class="strong">Returns:</strong> a pointer to a string that contains the name of the
specified cipher, or <code class="code">NULL</code> .
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fext_005fraw_005fparse-1"><span>gnutls_ext_raw_parse<a class="copiable-link" href="#gnutls_005fext_005fraw_005fparse-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fext_005fraw_005fparse"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fext_005fraw_005fparse"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ext_raw_parse</strong> <code class="def-code-arguments">(void * <var class="var">ctx</var>, gnutls_ext_raw_process_func <var class="var">cb</var>, const gnutls_datum_t * <var class="var">data</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fext_005fraw_005fparse"> &para;</a></span></dt>
<dd><p><var class="var">ctx</var>: a pointer to pass to callback function
</p>
<p><var class="var">cb</var>: callback function to process each extension found
</p>
<p><var class="var">data</var>: TLS extension data
</p>
<p><var class="var">flags</var>: should be zero or <code class="code">GNUTLS_EXT_RAW_FLAG_TLS_CLIENT_HELLO</code>  or <code class="code">GNUTLS_EXT_RAW_FLAG_DTLS_CLIENT_HELLO</code> 
</p>
<p>This function iterates through the TLS extensions as passed in
 <code class="code">data</code> , passing the individual extension data to callback. The
 <code class="code">data</code> must conform to Extension extensions&lt;0..2^16-1&gt; format.
</p>
<p>If flags is <code class="code">GNUTLS_EXT_RAW_TLS_FLAG_CLIENT_HELLO</code>  then this function
will parse the extension data from the position, as if the packet in
 <code class="code">data</code> is a client hello (without record or handshake headers) -
as provided by <code class="code">gnutls_handshake_set_hook_function()</code> .
</p>
<p>The return value of the callback will be propagated.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, or an error code. On unknown
flags it returns <code class="code">GNUTLS_E_INVALID_REQUEST</code> .
</p>
<p><strong class="strong">Since:</strong> 3.6.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fext_005fregister-1"><span>gnutls_ext_register<a class="copiable-link" href="#gnutls_005fext_005fregister-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fext_005fregister"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fext_005fregister"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ext_register</strong> <code class="def-code-arguments">(const char * <var class="var">name</var>, int <var class="var">id</var>, gnutls_ext_parse_type_t <var class="var">parse_point</var>, gnutls_ext_recv_func <var class="var">recv_func</var>, gnutls_ext_send_func <var class="var">send_func</var>, gnutls_ext_deinit_data_func <var class="var">deinit_func</var>, gnutls_ext_pack_func <var class="var">pack_func</var>, gnutls_ext_unpack_func <var class="var">unpack_func</var>)</code><a class="copiable-link" href="#index-gnutls_005fext_005fregister"> &para;</a></span></dt>
<dd><p><var class="var">name</var>: the name of the extension to register
</p>
<p><var class="var">id</var>: the numeric TLS id of the extension
</p>
<p><var class="var">parse_point</var>: the parse type of the extension (see gnutls_ext_parse_type_t)
</p>
<p><var class="var">recv_func</var>: a function to receive the data
</p>
<p><var class="var">send_func</var>: a function to send the data
</p>
<p><var class="var">deinit_func</var>: a function deinitialize any private data
</p>
<p><var class="var">pack_func</var>: a function which serializes the extension&rsquo;s private data (used on session packing for resumption)
</p>
<p><var class="var">unpack_func</var>: a function which will deserialize the extension&rsquo;s private data
</p>
<p>This function will register a new extension type. The extension will remain
registered until <code class="code">gnutls_global_deinit()</code>  is called. If the extension type
is already registered then <code class="code">GNUTLS_E_ALREADY_REGISTERED</code>  will be returned.
</p>
<p>Each registered extension can store temporary data into the gnutls_session_t
structure using <code class="code">gnutls_ext_set_data()</code> , and they can be retrieved using
<code class="code">gnutls_ext_get_data()</code> .
</p>
<p>Any extensions registered with this function are valid for the client
and TLS1.2 server hello (or encrypted extensions for TLS1.3).
</p>
<p>This function is not thread safe.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fext_005fset_005fdata-1"><span>gnutls_ext_set_data<a class="copiable-link" href="#gnutls_005fext_005fset_005fdata-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fext_005fset_005fdata"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fext_005fset_005fdata"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_ext_set_data</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, unsigned <var class="var">tls_id</var>, gnutls_ext_priv_data_t <var class="var">data</var>)</code><a class="copiable-link" href="#index-gnutls_005fext_005fset_005fdata"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: a <code class="code">gnutls_session_t</code>  opaque pointer
</p>
<p><var class="var">tls_id</var>: the numeric id of the extension
</p>
<p><var class="var">data</var>: the private data to set
</p>
<p>This function allows an extension handler to store data in the current session
and retrieve them later on. The set data will be deallocated using
the gnutls_ext_deinit_data_func.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005ffingerprint-1"><span>gnutls_fingerprint<a class="copiable-link" href="#gnutls_005ffingerprint-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005ffingerprint"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ffingerprint"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_fingerprint</strong> <code class="def-code-arguments">(gnutls_digest_algorithm_t <var class="var">algo</var>, const gnutls_datum_t * <var class="var">data</var>, void * <var class="var">result</var>, size_t * <var class="var">result_size</var>)</code><a class="copiable-link" href="#index-gnutls_005ffingerprint"> &para;</a></span></dt>
<dd><p><var class="var">algo</var>: is a digest algorithm
</p>
<p><var class="var">data</var>: is the data
</p>
<p><var class="var">result</var>: is the place where the result will be copied (may be null).
</p>
<p><var class="var">result_size</var>: should hold the size of the result. The actual size
of the returned result will also be copied there.
</p>
<p>This function will calculate a fingerprint (actually a hash), of
the given data.  The result is not printable data.  You should
convert it to hex, or to something else printable.
</p>
<p>This is the usual way to calculate a fingerprint of an X.509 DER
encoded certificate.  Note however that the fingerprint of an
OpenPGP certificate is not just a hash and cannot be calculated with this
function.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise
an error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005ffips140_005fcontext_005fdeinit-1"><span>gnutls_fips140_context_deinit<a class="copiable-link" href="#gnutls_005ffips140_005fcontext_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005ffips140_005fcontext_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ffips140_005fcontext_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_fips140_context_deinit</strong> <code class="def-code-arguments">(gnutls_fips140_context_t <var class="var">context</var>)</code><a class="copiable-link" href="#index-gnutls_005ffips140_005fcontext_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">context</var>: a <code class="code">gnutls_fips140_context_t</code> 
</p>
<p>Uninitialize and release the FIPS context  <code class="code">context</code> .
</p>
<p><strong class="strong">Since:</strong> 3.7.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005ffips140_005fcontext_005finit-1"><span>gnutls_fips140_context_init<a class="copiable-link" href="#gnutls_005ffips140_005fcontext_005finit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005ffips140_005fcontext_005finit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ffips140_005fcontext_005finit"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_fips140_context_init</strong> <code class="def-code-arguments">(gnutls_fips140_context_t * <var class="var">context</var>)</code><a class="copiable-link" href="#index-gnutls_005ffips140_005fcontext_005finit"> &para;</a></span></dt>
<dd><p><var class="var">context</var>: location to store  <code class="code">gnutls_fips140_context_t</code> 
</p>
<p>Create and initialize the FIPS context object.
</p>
<p><strong class="strong">Returns:</strong> 0 upon success, a negative error code otherwise
</p>
<p><strong class="strong">Since:</strong> 3.7.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005ffips140_005fget_005foperation_005fstate-1"><span>gnutls_fips140_get_operation_state<a class="copiable-link" href="#gnutls_005ffips140_005fget_005foperation_005fstate-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005ffips140_005fget_005foperation_005fstate"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ffips140_005fget_005foperation_005fstate-1"><span class="category-def">Function: </span><span><code class="def-type">gnutls_fips140_operation_state_t</code> <strong class="def-name">gnutls_fips140_get_operation_state</strong> <code class="def-code-arguments">(gnutls_fips140_context_t <var class="var">context</var>)</code><a class="copiable-link" href="#index-gnutls_005ffips140_005fget_005foperation_005fstate-1"> &para;</a></span></dt>
<dd><p><var class="var">context</var>: a <code class="code">gnutls_fips140_context_t</code> 
</p>
<p>Get the previous operation state of  <code class="code">context</code> in terms of FIPS.
</p>
<p><strong class="strong">Returns:</strong> a <code class="code">gnutls_fips140_operation_state_t</code> 
</p>
<p><strong class="strong">Since:</strong> 3.7.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005ffips140_005fmode_005fenabled-1"><span>gnutls_fips140_mode_enabled<a class="copiable-link" href="#gnutls_005ffips140_005fmode_005fenabled-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005ffips140_005fmode_005fenabled"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ffips140_005fmode_005fenabled"><span class="category-def">Function: </span><span><code class="def-type">unsigned</code> <strong class="def-name">gnutls_fips140_mode_enabled</strong> <code class="def-code-arguments">( <var class="var">void</var>)</code><a class="copiable-link" href="#index-gnutls_005ffips140_005fmode_005fenabled"> &para;</a></span></dt>
<dd>
<p>Checks whether this library is in FIPS140 mode. The returned
value corresponds to the library mode as set with
<code class="code">gnutls_fips140_set_mode()</code> .
</p>
<p>If <code class="code">gnutls_fips140_set_mode()</code>  was called with <code class="code">GNUTLS_FIPS140_SET_MODE_THREAD</code> 
then this function will return the current thread&rsquo;s FIPS140 mode, otherwise
the global value is returned.
</p>
<p><strong class="strong">Returns:</strong> return non-zero if true or zero if false.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005ffips140_005fpop_005fcontext-1"><span>gnutls_fips140_pop_context<a class="copiable-link" href="#gnutls_005ffips140_005fpop_005fcontext-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005ffips140_005fpop_005fcontext"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ffips140_005fpop_005fcontext"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_fips140_pop_context</strong> <code class="def-code-arguments">( <var class="var">void</var>)</code><a class="copiable-link" href="#index-gnutls_005ffips140_005fpop_005fcontext"> &para;</a></span></dt>
<dd>
<p>Dissociate the FIPS context currently
active on the current thread, reverting to the previously active
context. If a cryptographic operation is ongoing in the current
thread, e.g., <code class="code">gnutls_aead_cipher_init()</code>  is called but
<code class="code">gnutls_aead_cipher_deinit()</code>  is not yet called, it returns an error
<code class="code">GNUTLS_E_INVALID_REQUEST</code> .
</p>
<p>This function is no-op if FIPS140 is not compiled in nor enabled
at run-time.
</p>
<p><strong class="strong">Returns:</strong> 0 upon success, a negative error code otherwise
</p>
<p><strong class="strong">Since:</strong> 3.7.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005ffips140_005fpush_005fcontext-1"><span>gnutls_fips140_push_context<a class="copiable-link" href="#gnutls_005ffips140_005fpush_005fcontext-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005ffips140_005fpush_005fcontext"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ffips140_005fpush_005fcontext"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_fips140_push_context</strong> <code class="def-code-arguments">(gnutls_fips140_context_t <var class="var">context</var>)</code><a class="copiable-link" href="#index-gnutls_005ffips140_005fpush_005fcontext"> &para;</a></span></dt>
<dd><p><var class="var">context</var>: a <code class="code">gnutls_fips140_context_t</code> 
</p>
<p>Associate the FIPS  <code class="code">context</code> to the current thread, diverting the
currently active context. If a cryptographic operation is ongoing
in the current thread, e.g., <code class="code">gnutls_aead_cipher_init()</code>  is called
but <code class="code">gnutls_aead_cipher_deinit()</code>  is not yet called, it returns an
error <code class="code">GNUTLS_E_INVALID_REQUEST</code> .
</p>
<p>The operation state of  <code class="code">context</code> will be reset to
<code class="code">GNUTLS_FIPS140_OP_INITIAL</code> .
</p>
<p>This function is no-op if FIPS140 is not compiled in nor enabled
at run-time.
</p>
<p><strong class="strong">Returns:</strong> 0 upon success, a negative error code otherwise
</p>
<p><strong class="strong">Since:</strong> 3.7.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005ffips140_005frun_005fself_005ftests-1"><span>gnutls_fips140_run_self_tests<a class="copiable-link" href="#gnutls_005ffips140_005frun_005fself_005ftests-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005ffips140_005frun_005fself_005ftests"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ffips140_005frun_005fself_005ftests"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_fips140_run_self_tests</strong> <code class="def-code-arguments">( <var class="var">void</var>)</code><a class="copiable-link" href="#index-gnutls_005ffips140_005frun_005fself_005ftests"> &para;</a></span></dt>
<dd>
<p>Manually perform the second round of the FIPS140 self-tests,
including:
</p>
<p>- Known answer tests (KAT) for the selected set of symmetric
cipher, MAC, public key, KDF, and DRBG
- Library integrity checks
</p>
<p>Upon failure with FIPS140 mode enabled, it makes the library
unusable.  This function is not thread-safe.
</p>
<p><strong class="strong">Returns:</strong> 0 upon success, a negative error code otherwise
</p>
<p><strong class="strong">Since:</strong> 3.7.7
</p></dd></dl>

<h4 class="subheading" id="gnutls_005ffips140_005fset_005fmode-1"><span>gnutls_fips140_set_mode<a class="copiable-link" href="#gnutls_005ffips140_005fset_005fmode-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005ffips140_005fset_005fmode"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ffips140_005fset_005fmode"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_fips140_set_mode</strong> <code class="def-code-arguments">(gnutls_fips_mode_t <var class="var">mode</var>, unsigned <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005ffips140_005fset_005fmode"> &para;</a></span></dt>
<dd><p><var class="var">mode</var>: the FIPS140-2 mode to switch to
</p>
<p><var class="var">flags</var>: should be zero or <code class="code">GNUTLS_FIPS140_SET_MODE_THREAD</code> 
</p>
<p>That function is not thread-safe when changing the mode with no flags
(globally), and should be called prior to creating any threads. Its
behavior with no flags after threads are created is undefined.
</p>
<p>When the flag <code class="code">GNUTLS_FIPS140_SET_MODE_THREAD</code>  is specified
then this call will change the FIPS140-2 mode for this particular
thread and not for the whole process. That way an application
can utilize this function to set and reset mode for specific
operations.
</p>
<p>This function never fails but will be a no-op if used when
the library is not in FIPS140-2 mode. When asked to switch to unknown
values for  <code class="code">mode</code> or to <code class="code">GNUTLS_FIPS140_SELFTESTS</code>  mode, the library
switches to <code class="code">GNUTLS_FIPS140_STRICT</code>  mode.
</p>
<p><strong class="strong">Since:</strong> 3.6.2
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fget_005flibrary_005fconfig-1"><span>gnutls_get_library_config<a class="copiable-link" href="#gnutls_005fget_005flibrary_005fconfig-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fget_005flibrary_005fconfig"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fget_005flibrary_005fconfig"><span class="category-def">Function: </span><span><code class="def-type">const gnutls_library_config_st *</code> <strong class="def-name">gnutls_get_library_config</strong> <code class="def-code-arguments">( <var class="var">void</var>)</code><a class="copiable-link" href="#index-gnutls_005fget_005flibrary_005fconfig"> &para;</a></span></dt>
<dd>
<p>Returns the library configuration as key value pairs.
Currently defined keys are:
</p>
<p>- fips-module-name: the name of the FIPS140 module
</p>
<p>- fips-module-version: the version of the FIPS140 module
</p>
<p>- libgnutls-soname: the SONAME of the library itself
</p>
<p>- libnettle-soname: the library SONAME of linked libnettle
</p>
<p>- libhogweed-soname: the library SONAME of linked libhogweed
</p>
<p>- libgmp-soname: the library SONAME of linked libgmp
</p>
<p>- hardware-features: enabled hardware support features
</p>
<p>- tls-features: enabled TLS protocol features
</p>
<p><strong class="strong">Returns:</strong> a NUL-terminated <code class="code">gnutls_library_config_st</code>  array
</p>
<p><strong class="strong">Since:</strong> 3.7.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fget_005fsystem_005fconfig_005ffile-1"><span>gnutls_get_system_config_file<a class="copiable-link" href="#gnutls_005fget_005fsystem_005fconfig_005ffile-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fget_005fsystem_005fconfig_005ffile"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fget_005fsystem_005fconfig_005ffile-1"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_get_system_config_file</strong> <code class="def-code-arguments">( <var class="var">void</var>)</code><a class="copiable-link" href="#index-gnutls_005fget_005fsystem_005fconfig_005ffile-1"> &para;</a></span></dt>
<dd>
<p>Returns the filename of the system wide configuration
file to be loaded by the library.
</p>
<p><strong class="strong">Returns:</strong> a constant pointer to the config file path
</p>
<p><strong class="strong">Since:</strong> 3.6.9
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fglobal_005fdeinit-1"><span>gnutls_global_deinit<a class="copiable-link" href="#gnutls_005fglobal_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fglobal_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fglobal_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_global_deinit</strong> <code class="def-code-arguments">( <var class="var">void</var>)</code><a class="copiable-link" href="#index-gnutls_005fglobal_005fdeinit"> &para;</a></span></dt>
<dd>
<p>This function deinitializes the global data, that were initialized
using <code class="code">gnutls_global_init()</code> .
</p>
<p>Since GnuTLS 3.3.0 this function is no longer necessary to be explicitly
called. GnuTLS will automatically deinitialize on library destructor. See
<code class="code">gnutls_global_init()</code>  for disabling the implicit initialization/deinitialization.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fglobal_005finit-1"><span>gnutls_global_init<a class="copiable-link" href="#gnutls_005fglobal_005finit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fglobal_005finit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fglobal_005finit"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_global_init</strong> <code class="def-code-arguments">( <var class="var">void</var>)</code><a class="copiable-link" href="#index-gnutls_005fglobal_005finit"> &para;</a></span></dt>
<dd>
<p>Since GnuTLS 3.3.0 this function is no longer necessary to be explicitly
called. To disable the implicit call (in a library constructor) of this
function set the environment variable <code class="code">GNUTLS_NO_IMPLICIT_INIT</code>  to 1.
</p>
<p>This function performs any required precalculations, detects
the supported CPU capabilities and initializes the underlying
cryptographic backend. In order to free any resources 
taken by this call you should <code class="code">gnutls_global_deinit()</code>  
when gnutls usage is no longer needed.
</p>
<p>This function increments a global counter, so that
<code class="code">gnutls_global_deinit()</code>  only releases resources when it has been
called as many times as <code class="code">gnutls_global_init()</code> .  This is useful when
GnuTLS is used by more than one library in an application.  This
function can be called many times, but will only do something the
first time. It is thread safe since GnuTLS 3.3.0.
</p>
<p>A subsequent call of this function if the initial has failed will
return the same error code.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fglobal_005fset_005faudit_005flog_005ffunction-1"><span>gnutls_global_set_audit_log_function<a class="copiable-link" href="#gnutls_005fglobal_005fset_005faudit_005flog_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fglobal_005fset_005faudit_005flog_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fglobal_005fset_005faudit_005flog_005ffunction-1"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_global_set_audit_log_function</strong> <code class="def-code-arguments">(gnutls_audit_log_func <var class="var">log_func</var>)</code><a class="copiable-link" href="#index-gnutls_005fglobal_005fset_005faudit_005flog_005ffunction-1"> &para;</a></span></dt>
<dd><p><var class="var">log_func</var>: it is the audit log function
</p>
<p>This is the function to set the audit logging function. This
is a function to report important issues, such as possible
attacks in the protocol. This is different from <code class="code">gnutls_global_set_log_function()</code> 
because it will report also session-specific events. The session
parameter will be null if there is no corresponding TLS session.
</p>
<p><code class="code">gnutls_audit_log_func</code> is of the form,
void (*gnutls_audit_log_func)( gnutls_session_t, const char*);
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fglobal_005fset_005flog_005ffunction-1"><span>gnutls_global_set_log_function<a class="copiable-link" href="#gnutls_005fglobal_005fset_005flog_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fglobal_005fset_005flog_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fglobal_005fset_005flog_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_global_set_log_function</strong> <code class="def-code-arguments">(gnutls_log_func <var class="var">log_func</var>)</code><a class="copiable-link" href="#index-gnutls_005fglobal_005fset_005flog_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">log_func</var>: it&rsquo;s a log function
</p>
<p>This is the function where you set the logging function gnutls is
going to use.  This function only accepts a character array.
Normally you may not use this function since it is only used for
debugging purposes.
</p>
<p><code class="code">gnutls_log_func</code> is of the form,
void (*gnutls_log_func)( int level, const char*);
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fglobal_005fset_005flog_005flevel-1"><span>gnutls_global_set_log_level<a class="copiable-link" href="#gnutls_005fglobal_005fset_005flog_005flevel-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fglobal_005fset_005flog_005flevel"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fglobal_005fset_005flog_005flevel"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_global_set_log_level</strong> <code class="def-code-arguments">(int <var class="var">level</var>)</code><a class="copiable-link" href="#index-gnutls_005fglobal_005fset_005flog_005flevel"> &para;</a></span></dt>
<dd><p><var class="var">level</var>: it&rsquo;s an integer from 0 to 99.
</p>
<p>This is the function that allows you to set the log level.  The
level is an integer between 0 and 9.  Higher values mean more
verbosity. The default value is 0.  Larger values should only be
used with care, since they may reveal sensitive information.
</p>
<p>Use a log level over 10 to enable all debugging options.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fglobal_005fset_005fmutex-1"><span>gnutls_global_set_mutex<a class="copiable-link" href="#gnutls_005fglobal_005fset_005fmutex-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fglobal_005fset_005fmutex"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fglobal_005fset_005fmutex"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_global_set_mutex</strong> <code class="def-code-arguments">(mutex_init_func <var class="var">init</var>, mutex_deinit_func <var class="var">deinit</var>, mutex_lock_func <var class="var">lock</var>, mutex_unlock_func <var class="var">unlock</var>)</code><a class="copiable-link" href="#index-gnutls_005fglobal_005fset_005fmutex"> &para;</a></span></dt>
<dd><p><var class="var">init</var>: mutex initialization function
</p>
<p><var class="var">deinit</var>: mutex deinitialization function
</p>
<p><var class="var">lock</var>: mutex locking function
</p>
<p><var class="var">unlock</var>: mutex unlocking function
</p>
<p>With this function you are allowed to override the default mutex
locks used in some parts of gnutls and dependent libraries. This function
should be used if you have complete control of your program and libraries.
Do not call this function from a library, or preferably from any application
unless really needed to. GnuTLS will use the appropriate locks for the running
system.
</p>
<p>This function must be called prior to any other GnuTLS function; otherwise
the behavior is undefined.
</p>
<p><strong class="strong">Deprecated:</strong> This function is discouraged on GnuTLS 3.7.3 or later.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fglobal_005fset_005ftime_005ffunction-1"><span>gnutls_global_set_time_function<a class="copiable-link" href="#gnutls_005fglobal_005fset_005ftime_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fglobal_005fset_005ftime_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fglobal_005fset_005ftime_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_global_set_time_function</strong> <code class="def-code-arguments">(gnutls_time_func <var class="var">time_func</var>)</code><a class="copiable-link" href="#index-gnutls_005fglobal_005fset_005ftime_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">time_func</var>: it&rsquo;s the system time function, a <code class="code">gnutls_time_func()</code>  callback.
</p>
<p>This is the function where you can override the default system time
function.  The application provided function should behave the same
as the standard function.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fgost_005fparamset_005fget_005fname-1"><span>gnutls_gost_paramset_get_name<a class="copiable-link" href="#gnutls_005fgost_005fparamset_005fget_005fname-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fgost_005fparamset_005fget_005fname"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fgost_005fparamset_005fget_005fname"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_gost_paramset_get_name</strong> <code class="def-code-arguments">(gnutls_gost_paramset_t <var class="var">param</var>)</code><a class="copiable-link" href="#index-gnutls_005fgost_005fparamset_005fget_005fname"> &para;</a></span></dt>
<dd><p><var class="var">param</var>: is a GOST 28147 param set
</p>
<p>Convert a <code class="code">gnutls_gost_paramset_t</code>  value to a string.
</p>
<p><strong class="strong">Returns:</strong> a string that contains the name of the specified GOST param set,
or <code class="code">NULL</code> .
</p>
<p><strong class="strong">Since:</strong> 3.6.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fgost_005fparamset_005fget_005foid-1"><span>gnutls_gost_paramset_get_oid<a class="copiable-link" href="#gnutls_005fgost_005fparamset_005fget_005foid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fgost_005fparamset_005fget_005foid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fgost_005fparamset_005fget_005foid"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_gost_paramset_get_oid</strong> <code class="def-code-arguments">(gnutls_gost_paramset_t <var class="var">param</var>)</code><a class="copiable-link" href="#index-gnutls_005fgost_005fparamset_005fget_005foid"> &para;</a></span></dt>
<dd><p><var class="var">param</var>: is a GOST 28147 param set
</p>
<p>Convert a <code class="code">gnutls_gost_paramset_t</code>  value to its object identifier.
</p>
<p><strong class="strong">Returns:</strong> a string that contains the object identifier of the specified GOST
param set, or <code class="code">NULL</code> .
</p>
<p><strong class="strong">Since:</strong> 3.6.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fgroup_005fget-1"><span>gnutls_group_get<a class="copiable-link" href="#gnutls_005fgroup_005fget-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fgroup_005fget"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fgroup_005fget"><span class="category-def">Function: </span><span><code class="def-type">gnutls_group_t</code> <strong class="def-name">gnutls_group_get</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fgroup_005fget"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>Returns the currently used group for key exchange. Only valid
when using an elliptic curve or DH ciphersuite.
</p>
<p><strong class="strong">Returns:</strong> the currently used group, a <code class="code">gnutls_group_t</code> 
type.
</p>
<p><strong class="strong">Since:</strong> 3.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fgroup_005fget_005fid-1"><span>gnutls_group_get_id<a class="copiable-link" href="#gnutls_005fgroup_005fget_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fgroup_005fget_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fgroup_005fget_005fid"><span class="category-def">Function: </span><span><code class="def-type">gnutls_group_t</code> <strong class="def-name">gnutls_group_get_id</strong> <code class="def-code-arguments">(const char * <var class="var">name</var>)</code><a class="copiable-link" href="#index-gnutls_005fgroup_005fget_005fid"> &para;</a></span></dt>
<dd><p><var class="var">name</var>: is a group name
</p>
<p>The names are compared in a case insensitive way.
</p>
<p><strong class="strong">Returns:</strong> return a <code class="code">gnutls_group_t</code>  value corresponding to
the specified group, or <code class="code">GNUTLS_GROUP_INVALID</code>  on error.
</p>
<p><strong class="strong">Since:</strong> 3.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fgroup_005fget_005fname-1"><span>gnutls_group_get_name<a class="copiable-link" href="#gnutls_005fgroup_005fget_005fname-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fgroup_005fget_005fname"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fgroup_005fget_005fname"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_group_get_name</strong> <code class="def-code-arguments">(gnutls_group_t <var class="var">group</var>)</code><a class="copiable-link" href="#index-gnutls_005fgroup_005fget_005fname"> &para;</a></span></dt>
<dd><p><var class="var">group</var>: is an element from <code class="code">gnutls_group_t</code> 
</p>
<p>Convert a <code class="code">gnutls_group_t</code>  value to a string.
</p>
<p><strong class="strong">Returns:</strong> a string that contains the name of the specified
group or <code class="code">NULL</code> .
</p>
<p><strong class="strong">Since:</strong> 3.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fgroup_005flist-1"><span>gnutls_group_list<a class="copiable-link" href="#gnutls_005fgroup_005flist-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fgroup_005flist"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fgroup_005flist"><span class="category-def">Function: </span><span><code class="def-type">const gnutls_group_t *</code> <strong class="def-name">gnutls_group_list</strong> <code class="def-code-arguments">( <var class="var">void</var>)</code><a class="copiable-link" href="#index-gnutls_005fgroup_005flist"> &para;</a></span></dt>
<dd>
<p>Get the list of supported elliptic curves.
</p>
<p>This function is not thread safe.
</p>
<p><strong class="strong">Returns:</strong> Return a (0)-terminated list of <code class="code">gnutls_group_t</code> 
integers indicating the available groups.
</p>
<p><strong class="strong">Since:</strong> 3.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fhandshake-1"><span>gnutls_handshake<a class="copiable-link" href="#gnutls_005fhandshake-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fhandshake"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fhandshake-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_handshake</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fhandshake-1"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>This function performs the handshake of the TLS/SSL protocol, and
initializes the TLS session parameters.
</p>
<p>The non-fatal errors expected by this function are:
<code class="code">GNUTLS_E_INTERRUPTED</code> , <code class="code">GNUTLS_E_AGAIN</code> ,
<code class="code">GNUTLS_E_WARNING_ALERT_RECEIVED</code> . When this function is called
for re-handshake under TLS 1.2 or earlier, the non-fatal error code
<code class="code">GNUTLS_E_GOT_APPLICATION_DATA</code>  may also be returned.
</p>
<p>The former two interrupt the handshake procedure due to the transport
layer being interrupted, and the latter because of a &quot;warning&quot; alert that
was sent by the peer (it is always a good idea to check any
received alerts). On these non-fatal errors call this function again,
until it returns 0; cf.  <code class="code">gnutls_record_get_direction()</code>  and
<code class="code">gnutls_error_is_fatal()</code> . In DTLS sessions the non-fatal error
<code class="code">GNUTLS_E_LARGE_PACKET</code>  is also possible, and indicates that
the MTU should be adjusted.
</p>
<p>When this function is called by a server after a rehandshake request
under TLS 1.2 or earlier the <code class="code">GNUTLS_E_GOT_APPLICATION_DATA</code>  error code indicates
that some data were pending prior to peer initiating the handshake.
Under TLS 1.3 this function when called after a successful handshake, is a no-op
and always succeeds in server side; in client side this function is
equivalent to <code class="code">gnutls_session_key_update()</code>  with <code class="code">GNUTLS_KU_PEER</code>  flag.
</p>
<p>This function handles both full and abbreviated TLS handshakes (resumption).
For abbreviated handshakes, in client side, the <code class="code">gnutls_session_set_data()</code> 
should be called prior to this function to set parameters from a previous session.
In server side, resumption is handled by either setting a DB back-end, or setting
up keys for session tickets.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on a successful handshake, otherwise a negative error code.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fhandshake_005fdescription_005fget_005fname-1"><span>gnutls_handshake_description_get_name<a class="copiable-link" href="#gnutls_005fhandshake_005fdescription_005fget_005fname-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fhandshake_005fdescription_005fget_005fname"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fhandshake_005fdescription_005fget_005fname"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_handshake_description_get_name</strong> <code class="def-code-arguments">(gnutls_handshake_description_t <var class="var">type</var>)</code><a class="copiable-link" href="#index-gnutls_005fhandshake_005fdescription_005fget_005fname"> &para;</a></span></dt>
<dd><p><var class="var">type</var>: is a handshake message description
</p>
<p>Convert a <code class="code">gnutls_handshake_description_t</code>  value to a string.
</p>
<p><strong class="strong">Returns:</strong> a string that contains the name of the specified handshake
message or <code class="code">NULL</code> .
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fhandshake_005fget_005flast_005fin-1"><span>gnutls_handshake_get_last_in<a class="copiable-link" href="#gnutls_005fhandshake_005fget_005flast_005fin-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fhandshake_005fget_005flast_005fin"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fhandshake_005fget_005flast_005fin"><span class="category-def">Function: </span><span><code class="def-type">gnutls_handshake_description_t</code> <strong class="def-name">gnutls_handshake_get_last_in</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fhandshake_005fget_005flast_005fin"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>This function is only useful to check where the last performed
handshake failed.  If the previous handshake succeed or was not
performed at all then no meaningful value will be returned.
</p>
<p>Check <code class="code">gnutls_handshake_description_t</code>  in gnutls.h for the
available handshake descriptions.
</p>
<p><strong class="strong">Returns:</strong> the last handshake message type received, a
<code class="code">gnutls_handshake_description_t</code> .
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fhandshake_005fget_005flast_005fout-1"><span>gnutls_handshake_get_last_out<a class="copiable-link" href="#gnutls_005fhandshake_005fget_005flast_005fout-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fhandshake_005fget_005flast_005fout"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fhandshake_005fget_005flast_005fout"><span class="category-def">Function: </span><span><code class="def-type">gnutls_handshake_description_t</code> <strong class="def-name">gnutls_handshake_get_last_out</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fhandshake_005fget_005flast_005fout"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>This function is only useful to check where the last performed
handshake failed.  If the previous handshake succeed or was not
performed at all then no meaningful value will be returned.
</p>
<p>Check <code class="code">gnutls_handshake_description_t</code>  in gnutls.h for the
available handshake descriptions.
</p>
<p><strong class="strong">Returns:</strong> the last handshake message type sent, a
<code class="code">gnutls_handshake_description_t</code> .
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fhandshake_005fset_005fhook_005ffunction-1"><span>gnutls_handshake_set_hook_function<a class="copiable-link" href="#gnutls_005fhandshake_005fset_005fhook_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fhandshake_005fset_005fhook_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fhandshake_005fset_005fhook_005ffunction-1"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_handshake_set_hook_function</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, unsigned int <var class="var">htype</var>, int <var class="var">when</var>, gnutls_handshake_hook_func <var class="var">func</var>)</code><a class="copiable-link" href="#index-gnutls_005fhandshake_005fset_005fhook_005ffunction-1"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type
</p>
<p><var class="var">htype</var>: the <code class="code">gnutls_handshake_description_t</code>  of the message to hook at
</p>
<p><var class="var">when</var>: <code class="code">GNUTLS_HOOK_</code> * depending on when the hook function should be called
</p>
<p><var class="var">func</var>: is the function to be called
</p>
<p>This function will set a callback to be called after or before the specified
handshake message has been received or generated. This is a
generalization of <code class="code">gnutls_handshake_set_post_client_hello_function()</code> .
</p>
<p>To call the hook function prior to the message being generated or processed
use <code class="code">GNUTLS_HOOK_PRE</code>  as  <code class="code">when</code> parameter, <code class="code">GNUTLS_HOOK_POST</code>  to call
after, and <code class="code">GNUTLS_HOOK_BOTH</code>  for both cases.
</p>
<p>This callback must return 0 on success or a gnutls error code to
terminate the handshake.
</p>
<p>To hook at all handshake messages use an  <code class="code">htype</code> of <code class="code">GNUTLS_HANDSHAKE_ANY</code> .
</p>
<p><strong class="strong">Warning:</strong> You should not use this function to terminate the
handshake based on client input unless you know what you are
doing. Before the handshake is finished there is no way to know if
there is a man-in-the-middle attack being performed.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fhandshake_005fset_005fmax_005fpacket_005flength-1"><span>gnutls_handshake_set_max_packet_length<a class="copiable-link" href="#gnutls_005fhandshake_005fset_005fmax_005fpacket_005flength-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fhandshake_005fset_005fmax_005fpacket_005flength"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fhandshake_005fset_005fmax_005fpacket_005flength"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_handshake_set_max_packet_length</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, size_t <var class="var">max</var>)</code><a class="copiable-link" href="#index-gnutls_005fhandshake_005fset_005fmax_005fpacket_005flength"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">max</var>: is the maximum number.
</p>
<p>This function will set the maximum size of all handshake messages.
Handshakes over this size are rejected with
<code class="code">GNUTLS_E_HANDSHAKE_TOO_LARGE</code>  error code.  The default value is
128kb which is typically large enough.  Set this to 0 if you do not
want to set an upper limit.
</p>
<p>The reason for restricting the handshake message sizes are to
limit Denial of Service attacks.
</p>
<p>Note that the maximum handshake size was increased to 128kb
from 48kb in GnuTLS 3.5.5.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fhandshake_005fset_005fpost_005fclient_005fhello_005ffunction-1"><span>gnutls_handshake_set_post_client_hello_function<a class="copiable-link" href="#gnutls_005fhandshake_005fset_005fpost_005fclient_005fhello_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fhandshake_005fset_005fpost_005fclient_005fhello_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fhandshake_005fset_005fpost_005fclient_005fhello_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_handshake_set_post_client_hello_function</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_handshake_simple_hook_func <var class="var">func</var>)</code><a class="copiable-link" href="#index-gnutls_005fhandshake_005fset_005fpost_005fclient_005fhello_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">func</var>: is the function to be called
</p>
<p>This function will set a callback to be called after the client
hello has been received (callback valid in server side only). This
allows the server to adjust settings based on received extensions.
</p>
<p>Those settings could be ciphersuites, requesting certificate, or
anything else except for version negotiation (this is done before
the hello message is parsed).
</p>
<p>This callback must return 0 on success or a gnutls error code to
terminate the handshake.
</p>
<p>Since GnuTLS 3.3.5 the callback is
allowed to return <code class="code">GNUTLS_E_AGAIN</code>  or <code class="code">GNUTLS_E_INTERRUPTED</code>  to
put the handshake on hold. In that case <code class="code">gnutls_handshake()</code> 
will return <code class="code">GNUTLS_E_INTERRUPTED</code>  and can be resumed when needed.
</p>
<p><strong class="strong">Warning:</strong> You should not use this function to terminate the
handshake based on client input unless you know what you are
doing. Before the handshake is finished there is no way to know if
there is a man-in-the-middle attack being performed.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fhandshake_005fset_005fprivate_005fextensions-1"><span>gnutls_handshake_set_private_extensions<a class="copiable-link" href="#gnutls_005fhandshake_005fset_005fprivate_005fextensions-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fhandshake_005fset_005fprivate_005fextensions"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fhandshake_005fset_005fprivate_005fextensions"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_handshake_set_private_extensions</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, int <var class="var">allow</var>)</code><a class="copiable-link" href="#index-gnutls_005fhandshake_005fset_005fprivate_005fextensions"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">allow</var>: is an integer (0 or 1)
</p>
<p>This function will enable or disable the use of private cipher
suites (the ones that start with 0xFF).  By default or if  <code class="code">allow</code> is 0 then these cipher suites will not be advertised nor used.
</p>
<p>Currently GnuTLS does not include such cipher-suites or
compression algorithms.
</p>
<p>Enabling the private ciphersuites when talking to other than
gnutls servers and clients may cause interoperability problems.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fhandshake_005fset_005frandom-1"><span>gnutls_handshake_set_random<a class="copiable-link" href="#gnutls_005fhandshake_005fset_005frandom-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fhandshake_005fset_005frandom"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fhandshake_005fset_005frandom"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_handshake_set_random</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, const gnutls_datum_t * <var class="var">random</var>)</code><a class="copiable-link" href="#index-gnutls_005fhandshake_005fset_005frandom"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">random</var>: a random value of 32-bytes
</p>
<p>This function will explicitly set the server or client hello 
random value in the subsequent TLS handshake. The random value 
should be a 32-byte value.
</p>
<p>Note that this function should not normally be used as gnutls
will select automatically a random value for the handshake.
</p>
<p>This function should not be used when resuming a session.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, or an error code.
</p>
<p>Since 3.1.9
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fhandshake_005fset_005fread_005ffunction-1"><span>gnutls_handshake_set_read_function<a class="copiable-link" href="#gnutls_005fhandshake_005fset_005fread_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fhandshake_005fset_005fread_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fhandshake_005fset_005fread_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_handshake_set_read_function</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_handshake_read_func <var class="var">func</var>)</code><a class="copiable-link" href="#index-gnutls_005fhandshake_005fset_005fread_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is <code class="code">gnutls_session_t</code>  type
</p>
<p><var class="var">func</var>: is the function to be called
</p>
<p>This function will set a callback to be called when a handshake
message is being sent.
</p>
<p><strong class="strong">Since:</strong> 3.7.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fhandshake_005fset_005fsecret_005ffunction-1"><span>gnutls_handshake_set_secret_function<a class="copiable-link" href="#gnutls_005fhandshake_005fset_005fsecret_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fhandshake_005fset_005fsecret_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fhandshake_005fset_005fsecret_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_handshake_set_secret_function</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_handshake_secret_func <var class="var">func</var>)</code><a class="copiable-link" href="#index-gnutls_005fhandshake_005fset_005fsecret_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">func</var>: the secret func
</p>
<p>This function will set a callback to be called when a new traffic
secret is installed.
</p>
<p><strong class="strong">Since:</strong> 3.7.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fhandshake_005fset_005ftimeout-1"><span>gnutls_handshake_set_timeout<a class="copiable-link" href="#gnutls_005fhandshake_005fset_005ftimeout-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fhandshake_005fset_005ftimeout"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fhandshake_005fset_005ftimeout-1"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_handshake_set_timeout</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, unsigned int <var class="var">ms</var>)</code><a class="copiable-link" href="#index-gnutls_005fhandshake_005fset_005ftimeout-1"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">ms</var>: is a timeout value in milliseconds
</p>
<p>This function sets the timeout for the TLS handshake process
to the provided value. Use an  <code class="code">ms</code> value of zero to disable
timeout, or <code class="code">GNUTLS_DEFAULT_HANDSHAKE_TIMEOUT</code>  for a reasonable
default value. For the DTLS protocol, the more detailed
<code class="code">gnutls_dtls_set_timeouts()</code>  is provided.
</p>
<p>This function requires to set a pull timeout callback. See
<code class="code">gnutls_transport_set_pull_timeout_function()</code> .
</p>
<p><strong class="strong">Since:</strong> 3.1.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fhandshake_005fupdate_005freceiving_005fkey-1"><span>gnutls_handshake_update_receiving_key<a class="copiable-link" href="#gnutls_005fhandshake_005fupdate_005freceiving_005fkey-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fhandshake_005fupdate_005freceiving_005fkey"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fhandshake_005fupdate_005freceiving_005fkey"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_handshake_update_receiving_key</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fhandshake_005fupdate_005freceiving_005fkey"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>This function will update/refresh the session receiving keys when
the TLS protocol is 1.3 or better. Unlike <code class="code">gnutls_session_key_update()</code> 
this function does not notify the peer, it will only update
the local keys.
</p>
<p>If the negotiated version is not TLS 1.3 or better this
function will return <code class="code">GNUTLS_E_INVALID_REQUEST</code> .
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.8.11
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fhandshake_005fwrite-1"><span>gnutls_handshake_write<a class="copiable-link" href="#gnutls_005fhandshake_005fwrite-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fhandshake_005fwrite"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fhandshake_005fwrite"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_handshake_write</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_record_encryption_level_t <var class="var">level</var>, const void * <var class="var">data</var>, size_t <var class="var">data_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fhandshake_005fwrite"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">level</var>: the current encryption level for reading a handshake message
</p>
<p><var class="var">data</var>: the (const) handshake data to be processed
</p>
<p><var class="var">data_size</var>: the size of data
</p>
<p>This function processes a handshake message in the encryption level
specified with  <code class="code">level</code> . Prior to calling this function, a handshake
read callback must be set on  <code class="code">session</code> . Use
<code class="code">gnutls_handshake_set_read_function()</code>  to do this.
</p>
<p><strong class="strong">Since:</strong> 3.7.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fheartbeat_005fallowed-1"><span>gnutls_heartbeat_allowed<a class="copiable-link" href="#gnutls_005fheartbeat_005fallowed-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fheartbeat_005fallowed"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fheartbeat_005fallowed"><span class="category-def">Function: </span><span><code class="def-type">unsigned</code> <strong class="def-name">gnutls_heartbeat_allowed</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, unsigned int <var class="var">type</var>)</code><a class="copiable-link" href="#index-gnutls_005fheartbeat_005fallowed"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">type</var>: one of <code class="code">GNUTLS_HB_LOCAL_ALLOWED_TO_SEND</code>  and <code class="code">GNUTLS_HB_PEER_ALLOWED_TO_SEND</code> 
</p>
<p>This function will check whether heartbeats are allowed
to be sent or received in this session. 
</p>
<p><strong class="strong">Returns:</strong> Non zero if heartbeats are allowed.
</p>
<p><strong class="strong">Since:</strong> 3.1.2
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fheartbeat_005fenable-1"><span>gnutls_heartbeat_enable<a class="copiable-link" href="#gnutls_005fheartbeat_005fenable-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fheartbeat_005fenable"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fheartbeat_005fenable"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_heartbeat_enable</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, unsigned int <var class="var">type</var>)</code><a class="copiable-link" href="#index-gnutls_005fheartbeat_005fenable"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">type</var>: one of the GNUTLS_HB_* flags
</p>
<p>If this function is called with the <code class="code">GNUTLS_HB_PEER_ALLOWED_TO_SEND</code> 
 <code class="code">type</code> , GnuTLS will allow heartbeat messages to be received. Moreover it also
request the peer to accept heartbeat messages. This function
must be called prior to TLS handshake.
</p>
<p>If the  <code class="code">type</code> used is <code class="code">GNUTLS_HB_LOCAL_ALLOWED_TO_SEND</code> , then the peer
will be asked to accept heartbeat messages but not send ones.
</p>
<p>The function <code class="code">gnutls_heartbeat_allowed()</code>  can be used to test Whether
locally generated heartbeat messages can be accepted by the peer.
</p>
<p><strong class="strong">Since:</strong> 3.1.2
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fheartbeat_005fget_005ftimeout-1"><span>gnutls_heartbeat_get_timeout<a class="copiable-link" href="#gnutls_005fheartbeat_005fget_005ftimeout-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fheartbeat_005fget_005ftimeout"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fheartbeat_005fget_005ftimeout"><span class="category-def">Function: </span><span><code class="def-type">unsigned int</code> <strong class="def-name">gnutls_heartbeat_get_timeout</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fheartbeat_005fget_005ftimeout"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>This function will return the milliseconds remaining
for a retransmission of the previously sent ping
message. This function is useful when ping is used in
non-blocking mode, to estimate when to call <code class="code">gnutls_heartbeat_ping()</code> 
if no packets have been received.
</p>
<p><strong class="strong">Returns:</strong> the remaining time in milliseconds.
</p>
<p><strong class="strong">Since:</strong> 3.1.2
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fheartbeat_005fping-1"><span>gnutls_heartbeat_ping<a class="copiable-link" href="#gnutls_005fheartbeat_005fping-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fheartbeat_005fping"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fheartbeat_005fping"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_heartbeat_ping</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, size_t <var class="var">data_size</var>, unsigned int <var class="var">max_tries</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fheartbeat_005fping"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">data_size</var>: is the length of the ping payload.
</p>
<p><var class="var">max_tries</var>: if flags is <code class="code">GNUTLS_HEARTBEAT_WAIT</code>  then this sets the number of retransmissions. Use zero for indefinite (until timeout).
</p>
<p><var class="var">flags</var>: if <code class="code">GNUTLS_HEARTBEAT_WAIT</code>  then wait for pong or timeout instead of returning immediately.
</p>
<p>This function sends a ping to the peer. If the  <code class="code">flags</code> is set
to <code class="code">GNUTLS_HEARTBEAT_WAIT</code>  then it waits for a reply from the peer.
</p>
<p>Note that it is highly recommended to use this function with the
flag <code class="code">GNUTLS_HEARTBEAT_WAIT</code> , or you need to handle retransmissions
and timeouts manually.
</p>
<p>The total TLS data transmitted as part of the ping message are given by
the following formula: MAX(16,  <code class="code">data_size</code> )+<code class="code">gnutls_record_overhead_size()</code> +3.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.1.2
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fheartbeat_005fpong-1"><span>gnutls_heartbeat_pong<a class="copiable-link" href="#gnutls_005fheartbeat_005fpong-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fheartbeat_005fpong"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fheartbeat_005fpong"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_heartbeat_pong</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fheartbeat_005fpong"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">flags</var>: should be zero
</p>
<p>This function replies to a ping by sending a pong to the peer.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.1.2
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fheartbeat_005fset_005ftimeouts-1"><span>gnutls_heartbeat_set_timeouts<a class="copiable-link" href="#gnutls_005fheartbeat_005fset_005ftimeouts-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fheartbeat_005fset_005ftimeouts"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fheartbeat_005fset_005ftimeouts"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_heartbeat_set_timeouts</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, unsigned int <var class="var">retrans_timeout</var>, unsigned int <var class="var">total_timeout</var>)</code><a class="copiable-link" href="#index-gnutls_005fheartbeat_005fset_005ftimeouts"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">retrans_timeout</var>: The time at which a retransmission will occur in milliseconds
</p>
<p><var class="var">total_timeout</var>: The time at which the connection will be aborted, in milliseconds.
</p>
<p>This function will override the timeouts for the DTLS heartbeat
protocol. The retransmission timeout is the time after which a
message from the peer is not received, the previous request will
be retransmitted. The total timeout is the time after which the
handshake will be aborted with <code class="code">GNUTLS_E_TIMEDOUT</code> .
</p>
<p><strong class="strong">Since:</strong> 3.1.2
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fhex2bin-1"><span>gnutls_hex2bin<a class="copiable-link" href="#gnutls_005fhex2bin-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fhex2bin"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fhex2bin"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_hex2bin</strong> <code class="def-code-arguments">(const char * <var class="var">hex_data</var>, size_t <var class="var">hex_size</var>, void * <var class="var">bin_data</var>, size_t * <var class="var">bin_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fhex2bin"> &para;</a></span></dt>
<dd><p><var class="var">hex_data</var>: string with data in hex format
</p>
<p><var class="var">hex_size</var>: size of hex data
</p>
<p><var class="var">bin_data</var>: output array with binary data
</p>
<p><var class="var">bin_size</var>: when calling should hold maximum size of  <code class="code">bin_data</code> ,
on return will hold actual length of  <code class="code">bin_data</code> .
</p>
<p>Convert a buffer with hex data to binary data. This function
unlike <code class="code">gnutls_hex_decode()</code>  can parse hex data with separators
between numbers. That is, it ignores any non-hex characters.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 2.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fhex_005fdecode-1"><span>gnutls_hex_decode<a class="copiable-link" href="#gnutls_005fhex_005fdecode-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fhex_005fdecode"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fhex_005fdecode"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_hex_decode</strong> <code class="def-code-arguments">(const gnutls_datum_t * <var class="var">hex_data</var>, void * <var class="var">result</var>, size_t * <var class="var">result_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fhex_005fdecode"> &para;</a></span></dt>
<dd><p><var class="var">hex_data</var>: contain the encoded data
</p>
<p><var class="var">result</var>: the place where decoded data will be copied
</p>
<p><var class="var">result_size</var>: holds the size of the result
</p>
<p>This function will decode the given encoded data, using the hex
encoding used by PSK password files.
</p>
<p>Initially  <code class="code">result_size</code> must hold the maximum size available in
 <code class="code">result</code> , and on return it will contain the number of bytes written.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  if the buffer given is not
long enough, <code class="code">GNUTLS_E_PARSING_ERROR</code>  on invalid hex data, or 0 on success.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fhex_005fdecode2-1"><span>gnutls_hex_decode2<a class="copiable-link" href="#gnutls_005fhex_005fdecode2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fhex_005fdecode2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fhex_005fdecode2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_hex_decode2</strong> <code class="def-code-arguments">(const gnutls_datum_t * <var class="var">hex_data</var>, gnutls_datum_t * <var class="var">result</var>)</code><a class="copiable-link" href="#index-gnutls_005fhex_005fdecode2"> &para;</a></span></dt>
<dd><p><var class="var">hex_data</var>: contain the encoded data
</p>
<p><var class="var">result</var>: the result in an allocated string
</p>
<p>This function will decode the given encoded data, using the hex
encoding used by PSK password files.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_PARSING_ERROR</code>  on invalid hex data, or 0 on success.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fhex_005fencode-1"><span>gnutls_hex_encode<a class="copiable-link" href="#gnutls_005fhex_005fencode-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fhex_005fencode"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fhex_005fencode"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_hex_encode</strong> <code class="def-code-arguments">(const gnutls_datum_t * <var class="var">data</var>, char * <var class="var">result</var>, size_t * <var class="var">result_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fhex_005fencode"> &para;</a></span></dt>
<dd><p><var class="var">data</var>: contain the raw data
</p>
<p><var class="var">result</var>: the place where hex data will be copied
</p>
<p><var class="var">result_size</var>: holds the size of the result
</p>
<p>This function will convert the given data to printable data, using
the hex encoding, as used in the PSK password files.
</p>
<p>Note that the size of the result includes the null terminator.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  if the buffer given is not
long enough, or 0 on success.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fhex_005fencode2-1"><span>gnutls_hex_encode2<a class="copiable-link" href="#gnutls_005fhex_005fencode2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fhex_005fencode2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fhex_005fencode2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_hex_encode2</strong> <code class="def-code-arguments">(const gnutls_datum_t * <var class="var">data</var>, gnutls_datum_t * <var class="var">result</var>)</code><a class="copiable-link" href="#index-gnutls_005fhex_005fencode2"> &para;</a></span></dt>
<dd><p><var class="var">data</var>: contain the raw data
</p>
<p><var class="var">result</var>: the result in an allocated string
</p>
<p>This function will convert the given data to printable data, using
the hex encoding, as used in the PSK password files.
</p>
<p>Note that the size of the result does NOT include the null terminator.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fidna_005fmap-1"><span>gnutls_idna_map<a class="copiable-link" href="#gnutls_005fidna_005fmap-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fidna_005fmap"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fidna_005fmap"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_idna_map</strong> <code class="def-code-arguments">(const char * <var class="var">input</var>, unsigned <var class="var">ilen</var>, gnutls_datum_t * <var class="var">out</var>, unsigned <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fidna_005fmap"> &para;</a></span></dt>
<dd><p><var class="var">input</var>: contain the UTF-8 formatted domain name
</p>
<p><var class="var">ilen</var>: the length of the provided string
</p>
<p><var class="var">out</var>: the result in an null-terminated allocated string
</p>
<p><var class="var">flags</var>: should be zero
</p>
<p>This function will convert the provided UTF-8 domain name, to
its IDNA mapping in an allocated variable. Note that depending on the flags the used gnutls
library was compiled with, the output of this function may vary (i.e.,
may be IDNA2008, or IDNA2003).
</p>
<p>To force IDNA2008 specify the flag <code class="code">GNUTLS_IDNA_FORCE_2008</code> . In
the case GnuTLS is not compiled with the necessary dependencies,
<code class="code">GNUTLS_E_UNIMPLEMENTED_FEATURE</code>  will be returned to indicate that
gnutls is unable to perform the requested conversion.
</p>
<p>Note also, that this function will return an empty string if an
empty string is provided as input.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_INVALID_UTF8_STRING</code>  on invalid UTF-8 data, or 0 on success.
</p>
<p><strong class="strong">Since:</strong> 3.5.8
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fidna_005freverse_005fmap-1"><span>gnutls_idna_reverse_map<a class="copiable-link" href="#gnutls_005fidna_005freverse_005fmap-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fidna_005freverse_005fmap"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fidna_005freverse_005fmap"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_idna_reverse_map</strong> <code class="def-code-arguments">(const char * <var class="var">input</var>, unsigned <var class="var">ilen</var>, gnutls_datum_t * <var class="var">out</var>, unsigned <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fidna_005freverse_005fmap"> &para;</a></span></dt>
<dd><p><var class="var">input</var>: contain the ACE (IDNA) formatted domain name
</p>
<p><var class="var">ilen</var>: the length of the provided string
</p>
<p><var class="var">out</var>: the result in an null-terminated allocated UTF-8 string
</p>
<p><var class="var">flags</var>: should be zero
</p>
<p>This function will convert an ACE (ASCII-encoded) domain name to a UTF-8 domain name.
</p>
<p>If GnuTLS is compiled without IDNA support, then this function
will return <code class="code">GNUTLS_E_UNIMPLEMENTED_FEATURE</code> .
</p>
<p>Note also, that this function will return an empty string if an
empty string is provided as input.
</p>
<p><strong class="strong">Returns:</strong> A negative error code on error, or 0 on success.
</p>
<p><strong class="strong">Since:</strong> 3.5.8
</p></dd></dl>

<h4 class="subheading" id="gnutls_005finit-1"><span>gnutls_init<a class="copiable-link" href="#gnutls_005finit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005finit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005finit-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_init</strong> <code class="def-code-arguments">(gnutls_session_t * <var class="var">session</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005finit-1"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a pointer to a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">flags</var>: indicate if this session is to be used for server or client.
</p>
<p>This function initializes the provided session. Every session must
be initialized before use, and after successful initialization and
use must be deinitialized by calling <code class="code">gnutls_deinit()</code> .
</p>
<p><code class="code">flags</code> can be any combination of flags from <code class="code">gnutls_init_flags_t</code> .
</p>
<p>Note that since version 3.1.2 this function enables some common
TLS extensions such as session tickets and OCSP certificate status
request in client side by default. To prevent that use the <code class="code">GNUTLS_NO_DEFAULT_EXTENSIONS</code> 
flag.
</p>
<p>Note that it is never mandatory to use <code class="code">gnutls_deinit()</code>  after this
function fails.  Since gnutls 3.8.0, it is safe to unconditionally
use <code class="code">gnutls_deinit()</code>  even after failure regardless of whether the
memory was initialized prior to <code class="code">gnutls_init()</code> ; however, clients
wanting to be portable to older versions of the library should
either skip deinitialization on failure, or pre-initialize the
memory passed in to <code class="code">gnutls_init()</code>  to all zeroes via <code class="code">memset()</code>  or
similar.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, or an error code.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fkey_005fgenerate-1"><span>gnutls_key_generate<a class="copiable-link" href="#gnutls_005fkey_005fgenerate-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fkey_005fgenerate"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fkey_005fgenerate"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_key_generate</strong> <code class="def-code-arguments">(gnutls_datum_t * <var class="var">key</var>, unsigned int <var class="var">key_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fkey_005fgenerate"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: is a pointer to a <code class="code">gnutls_datum_t</code>  which will contain a newly
created key
</p>
<p><var class="var">key_size</var>: the number of bytes of the key
</p>
<p>Generates a random key of  <code class="code">key_size</code> bytes.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, or an
error code.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fkx_005fget-1"><span>gnutls_kx_get<a class="copiable-link" href="#gnutls_005fkx_005fget-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fkx_005fget"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fkx_005fget"><span class="category-def">Function: </span><span><code class="def-type">gnutls_kx_algorithm_t</code> <strong class="def-name">gnutls_kx_get</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fkx_005fget"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>Get the currently used key exchange algorithm.
</p>
<p>This function will return <code class="code">GNUTLS_KX_ECDHE_RSA</code> , or <code class="code">GNUTLS_KX_DHE_RSA</code> 
under TLS 1.3, to indicate an elliptic curve DH key exchange or
a finite field one. The precise group used is available
by calling <code class="code">gnutls_group_get()</code>  instead.
</p>
<p><strong class="strong">Returns:</strong> the key exchange algorithm used in the last handshake, a
<code class="code">gnutls_kx_algorithm_t</code>  value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fkx_005fget_005fid-1"><span>gnutls_kx_get_id<a class="copiable-link" href="#gnutls_005fkx_005fget_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fkx_005fget_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fkx_005fget_005fid"><span class="category-def">Function: </span><span><code class="def-type">gnutls_kx_algorithm_t</code> <strong class="def-name">gnutls_kx_get_id</strong> <code class="def-code-arguments">(const char * <var class="var">name</var>)</code><a class="copiable-link" href="#index-gnutls_005fkx_005fget_005fid"> &para;</a></span></dt>
<dd><p><var class="var">name</var>: is a KX name
</p>
<p>Convert a string to a <code class="code">gnutls_kx_algorithm_t</code>  value.  The names are
compared in a case insensitive way.
</p>
<p><strong class="strong">Returns:</strong> an id of the specified KX algorithm, or <code class="code">GNUTLS_KX_UNKNOWN</code> 
on error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fkx_005fget_005fname-1"><span>gnutls_kx_get_name<a class="copiable-link" href="#gnutls_005fkx_005fget_005fname-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fkx_005fget_005fname"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fkx_005fget_005fname"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_kx_get_name</strong> <code class="def-code-arguments">(gnutls_kx_algorithm_t <var class="var">algorithm</var>)</code><a class="copiable-link" href="#index-gnutls_005fkx_005fget_005fname"> &para;</a></span></dt>
<dd><p><var class="var">algorithm</var>: is a key exchange algorithm
</p>
<p>Convert a <code class="code">gnutls_kx_algorithm_t</code>  value to a string.
</p>
<p><strong class="strong">Returns:</strong> a pointer to a string that contains the name of the
specified key exchange algorithm, or <code class="code">NULL</code> .
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fkx_005flist-1"><span>gnutls_kx_list<a class="copiable-link" href="#gnutls_005fkx_005flist-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fkx_005flist"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fkx_005flist"><span class="category-def">Function: </span><span><code class="def-type">const gnutls_kx_algorithm_t *</code> <strong class="def-name">gnutls_kx_list</strong> <code class="def-code-arguments">( <var class="var">void</var>)</code><a class="copiable-link" href="#index-gnutls_005fkx_005flist"> &para;</a></span></dt>
<dd>
<p>Get a list of supported key exchange algorithms.
</p>
<p>This function is not thread safe.
</p>
<p><strong class="strong">Returns:</strong> a (0)-terminated list of <code class="code">gnutls_kx_algorithm_t</code>  integers
indicating the available key exchange algorithms.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fload_005ffile-1"><span>gnutls_load_file<a class="copiable-link" href="#gnutls_005fload_005ffile-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fload_005ffile"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fload_005ffile"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_load_file</strong> <code class="def-code-arguments">(const char * <var class="var">filename</var>, gnutls_datum_t * <var class="var">data</var>)</code><a class="copiable-link" href="#index-gnutls_005fload_005ffile"> &para;</a></span></dt>
<dd><p><var class="var">filename</var>: the name of the file to load
</p>
<p><var class="var">data</var>: Where the file will be stored
</p>
<p>This function will load a file into a datum. The data are
zero terminated but the terminating null is not included in length.
The returned data are allocated using <code class="code">gnutls_malloc()</code> .
</p>
<p>Note that this function is not designed for reading sensitive materials,
such as private keys, on practical applications. When the reading fails
in the middle, the partially loaded content might remain on memory.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise
an error code is returned.
</p>
<p>Since 3.1.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fmac_005fget-1"><span>gnutls_mac_get<a class="copiable-link" href="#gnutls_005fmac_005fget-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fmac_005fget"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fmac_005fget"><span class="category-def">Function: </span><span><code class="def-type">gnutls_mac_algorithm_t</code> <strong class="def-name">gnutls_mac_get</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fmac_005fget"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>Get the currently used MAC algorithm.
</p>
<p><strong class="strong">Returns:</strong> the currently used mac algorithm, a
<code class="code">gnutls_mac_algorithm_t</code>  value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fmac_005fget_005fid-1"><span>gnutls_mac_get_id<a class="copiable-link" href="#gnutls_005fmac_005fget_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fmac_005fget_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fmac_005fget_005fid"><span class="category-def">Function: </span><span><code class="def-type">gnutls_mac_algorithm_t</code> <strong class="def-name">gnutls_mac_get_id</strong> <code class="def-code-arguments">(const char * <var class="var">name</var>)</code><a class="copiable-link" href="#index-gnutls_005fmac_005fget_005fid"> &para;</a></span></dt>
<dd><p><var class="var">name</var>: is a MAC algorithm name
</p>
<p>Convert a string to a <code class="code">gnutls_mac_algorithm_t</code>  value.  The names are
compared in a case insensitive way.
</p>
<p><strong class="strong">Returns:</strong> a <code class="code">gnutls_mac_algorithm_t</code>  id of the specified MAC
algorithm string, or <code class="code">GNUTLS_MAC_UNKNOWN</code>  on failure.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fmac_005fget_005fkey_005fsize-1"><span>gnutls_mac_get_key_size<a class="copiable-link" href="#gnutls_005fmac_005fget_005fkey_005fsize-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fmac_005fget_005fkey_005fsize"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fmac_005fget_005fkey_005fsize"><span class="category-def">Function: </span><span><code class="def-type">size_t</code> <strong class="def-name">gnutls_mac_get_key_size</strong> <code class="def-code-arguments">(gnutls_mac_algorithm_t <var class="var">algorithm</var>)</code><a class="copiable-link" href="#index-gnutls_005fmac_005fget_005fkey_005fsize"> &para;</a></span></dt>
<dd><p><var class="var">algorithm</var>: is an encryption algorithm
</p>
<p>Returns the size of the MAC key used in TLS.
</p>
<p><strong class="strong">Returns:</strong> length (in bytes) of the given MAC key size, or 0 if the
given MAC algorithm is invalid.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fmac_005fget_005fname-1"><span>gnutls_mac_get_name<a class="copiable-link" href="#gnutls_005fmac_005fget_005fname-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fmac_005fget_005fname"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fmac_005fget_005fname"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_mac_get_name</strong> <code class="def-code-arguments">(gnutls_mac_algorithm_t <var class="var">algorithm</var>)</code><a class="copiable-link" href="#index-gnutls_005fmac_005fget_005fname"> &para;</a></span></dt>
<dd><p><var class="var">algorithm</var>: is a MAC algorithm
</p>
<p>Convert a <code class="code">gnutls_mac_algorithm_t</code>  value to a string.
</p>
<p><strong class="strong">Returns:</strong> a string that contains the name of the specified MAC
algorithm, or <code class="code">NULL</code> .
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fmac_005flist-1"><span>gnutls_mac_list<a class="copiable-link" href="#gnutls_005fmac_005flist-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fmac_005flist"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fmac_005flist"><span class="category-def">Function: </span><span><code class="def-type">const gnutls_mac_algorithm_t *</code> <strong class="def-name">gnutls_mac_list</strong> <code class="def-code-arguments">( <var class="var">void</var>)</code><a class="copiable-link" href="#index-gnutls_005fmac_005flist"> &para;</a></span></dt>
<dd>
<p>Get a list of hash algorithms for use as MACs.  Note that not
necessarily all MACs are supported in TLS cipher suites.
This function is not thread safe.
</p>
<p><strong class="strong">Returns:</strong> Return a (0)-terminated list of <code class="code">gnutls_mac_algorithm_t</code> 
integers indicating the available MACs.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fmemcmp-1"><span>gnutls_memcmp<a class="copiable-link" href="#gnutls_005fmemcmp-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fmemcmp"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fmemcmp"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_memcmp</strong> <code class="def-code-arguments">(const void * <var class="var">s1</var>, const void * <var class="var">s2</var>, size_t <var class="var">n</var>)</code><a class="copiable-link" href="#index-gnutls_005fmemcmp"> &para;</a></span></dt>
<dd><p><var class="var">s1</var>: the first address to compare
</p>
<p><var class="var">s2</var>: the second address to compare
</p>
<p><var class="var">n</var>: the size of memory to compare
</p>
<p>This function will operate similarly to <code class="code">memcmp()</code> , but will operate
on time that depends only on the size of the string. That is will
not return early if the strings don&rsquo;t match on the first byte.
</p>
<p><strong class="strong">Returns:</strong> non zero on difference and zero if the buffers are identical.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fmemset-1"><span>gnutls_memset<a class="copiable-link" href="#gnutls_005fmemset-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fmemset"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fmemset"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_memset</strong> <code class="def-code-arguments">(void * <var class="var">data</var>, int <var class="var">c</var>, size_t <var class="var">size</var>)</code><a class="copiable-link" href="#index-gnutls_005fmemset"> &para;</a></span></dt>
<dd><p><var class="var">data</var>: the memory to set
</p>
<p><var class="var">c</var>: the constant byte to fill the memory with
</p>
<p><var class="var">size</var>: the size of memory
</p>
<p>This function will operate similarly to <code class="code">memset()</code> , but will
not be optimized out by the compiler.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005focsp_005fstatus_005frequest_005fenable_005fclient-1"><span>gnutls_ocsp_status_request_enable_client<a class="copiable-link" href="#gnutls_005focsp_005fstatus_005frequest_005fenable_005fclient-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005focsp_005fstatus_005frequest_005fenable_005fclient"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005fstatus_005frequest_005fenable_005fclient"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ocsp_status_request_enable_client</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_datum_t * <var class="var">responder_id</var>, size_t <var class="var">responder_id_size</var>, gnutls_datum_t * <var class="var">extensions</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005fstatus_005frequest_005fenable_005fclient"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">responder_id</var>: ignored, must be <code class="code">NULL</code> 
</p>
<p><var class="var">responder_id_size</var>: ignored, must be zero
</p>
<p><var class="var">extensions</var>: ignored, must be <code class="code">NULL</code> 
</p>
<p>This function is to be used by clients to request OCSP response
from the server, using the &quot;status_request&quot; TLS extension.  Only
OCSP status type is supported.
</p>
<p>Previous versions of GnuTLS supported setting  <code class="code">responder_id</code> and
 <code class="code">extensions</code> fields, but due to the difficult semantics of the
parameter usage, and other issues, this support was removed
since 3.6.0 and these parameters must be set to <code class="code">NULL</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned.
</p>
<p><strong class="strong">Since:</strong> 3.1.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005focsp_005fstatus_005frequest_005fget-1"><span>gnutls_ocsp_status_request_get<a class="copiable-link" href="#gnutls_005focsp_005fstatus_005frequest_005fget-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005focsp_005fstatus_005frequest_005fget"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005fstatus_005frequest_005fget"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ocsp_status_request_get</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_datum_t * <var class="var">response</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005fstatus_005frequest_005fget"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">response</var>: a <code class="code">gnutls_datum_t</code>  with DER encoded OCSP response
</p>
<p>This function returns the OCSP status response received
from the TLS server. The  <code class="code">response</code> should be treated as
constant. If no OCSP response is available then
<code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  is returned.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned.
</p>
<p><strong class="strong">Since:</strong> 3.1.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005focsp_005fstatus_005frequest_005fget2-1"><span>gnutls_ocsp_status_request_get2<a class="copiable-link" href="#gnutls_005focsp_005fstatus_005frequest_005fget2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005focsp_005fstatus_005frequest_005fget2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005fstatus_005frequest_005fget2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ocsp_status_request_get2</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, unsigned <var class="var">idx</var>, gnutls_datum_t * <var class="var">response</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005fstatus_005frequest_005fget2"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">idx</var>: the index of peer&rsquo;s certificate
</p>
<p><var class="var">response</var>: a <code class="code">gnutls_datum_t</code>  with DER encoded OCSP response
</p>
<p>This function returns the OCSP status response received
from the TLS server for the certificate index provided.
The index corresponds to certificates as returned by
gnutls_certificate_get_peers. When index is zero this
function operates identically to <code class="code">gnutls_ocsp_status_request_get()</code> .
</p>
<p>The returned  <code class="code">response</code> should be treated as
constant. If no OCSP response is available for the
given index then <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> 
is returned.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned.
</p>
<p><strong class="strong">Since:</strong> 3.6.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005focsp_005fstatus_005frequest_005fis_005fchecked-1"><span>gnutls_ocsp_status_request_is_checked<a class="copiable-link" href="#gnutls_005focsp_005fstatus_005frequest_005fis_005fchecked-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005focsp_005fstatus_005frequest_005fis_005fchecked"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005fstatus_005frequest_005fis_005fchecked"><span class="category-def">Function: </span><span><code class="def-type">unsigned</code> <strong class="def-name">gnutls_ocsp_status_request_is_checked</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005fstatus_005frequest_005fis_005fchecked"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a gnutls session
</p>
<p><var class="var">flags</var>: should be zero or <code class="code">GNUTLS_OCSP_SR_IS_AVAIL</code> 
</p>
<p>When flags are zero this function returns non-zero if a valid OCSP status
response was included in the TLS handshake. That is, an OCSP status response
which is not too old, superseded or marks the certificate as revoked.
It returns zero otherwise.
</p>
<p>When the flag <code class="code">GNUTLS_OCSP_SR_IS_AVAIL</code>  is specified, the function
returns non-zero if an OCSP status response was included in the handshake
even if it was invalid. Otherwise, if no OCSP status response was included,
it returns zero. The <code class="code">GNUTLS_OCSP_SR_IS_AVAIL</code>  flag was introduced in GnuTLS 3.4.0.
</p>
<p>This is a helper function when needing to decide whether to perform an
explicit OCSP validity check on the peer&rsquo;s certificate. Should be called after
any of gnutls_certificate_verify_peers*() are called.
</p>
<p>This function is always usable on client side, but on server side only under
TLS 1.3, which is the first version of TLS that allows clients to send OCSP
responses.
</p>
<p><strong class="strong">Returns:</strong> Non-zero if the response was valid, or a zero if it wasn&rsquo;t sent,
or sent and was invalid.
</p>
<p><strong class="strong">Since:</strong> 3.1.4
</p></dd></dl>

<h4 class="subheading" id="gnutls_005foid_005fto_005fdigest-1"><span>gnutls_oid_to_digest<a class="copiable-link" href="#gnutls_005foid_005fto_005fdigest-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005foid_005fto_005fdigest"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005foid_005fto_005fdigest"><span class="category-def">Function: </span><span><code class="def-type">gnutls_digest_algorithm_t</code> <strong class="def-name">gnutls_oid_to_digest</strong> <code class="def-code-arguments">(const char * <var class="var">oid</var>)</code><a class="copiable-link" href="#index-gnutls_005foid_005fto_005fdigest"> &para;</a></span></dt>
<dd><p><var class="var">oid</var>: is an object identifier
</p>
<p>Converts a textual object identifier to a <code class="code">gnutls_digest_algorithm_t</code>  value.
</p>
<p><strong class="strong">Returns:</strong> a <code class="code">gnutls_digest_algorithm_t</code>  id of the specified digest
algorithm, or <code class="code">GNUTLS_DIG_UNKNOWN</code>  on failure.
</p>
<p><strong class="strong">Since:</strong> 3.4.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005foid_005fto_005fecc_005fcurve-1"><span>gnutls_oid_to_ecc_curve<a class="copiable-link" href="#gnutls_005foid_005fto_005fecc_005fcurve-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005foid_005fto_005fecc_005fcurve"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005foid_005fto_005fecc_005fcurve"><span class="category-def">Function: </span><span><code class="def-type">gnutls_ecc_curve_t</code> <strong class="def-name">gnutls_oid_to_ecc_curve</strong> <code class="def-code-arguments">(const char * <var class="var">oid</var>)</code><a class="copiable-link" href="#index-gnutls_005foid_005fto_005fecc_005fcurve"> &para;</a></span></dt>
<dd><p><var class="var">oid</var>: is a curve&rsquo;s OID
</p>

<p><strong class="strong">Returns:</strong> return a <code class="code">gnutls_ecc_curve_t</code>  value corresponding to
the specified OID, or <code class="code">GNUTLS_ECC_CURVE_INVALID</code>  on error.
</p>
<p><strong class="strong">Since:</strong> 3.4.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005foid_005fto_005fgost_005fparamset-1"><span>gnutls_oid_to_gost_paramset<a class="copiable-link" href="#gnutls_005foid_005fto_005fgost_005fparamset-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005foid_005fto_005fgost_005fparamset"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005foid_005fto_005fgost_005fparamset"><span class="category-def">Function: </span><span><code class="def-type">gnutls_gost_paramset_t</code> <strong class="def-name">gnutls_oid_to_gost_paramset</strong> <code class="def-code-arguments">(const char * <var class="var">oid</var>)</code><a class="copiable-link" href="#index-gnutls_005foid_005fto_005fgost_005fparamset"> &para;</a></span></dt>
<dd><p><var class="var">oid</var>: is an object identifier
</p>
<p>Converts a textual object identifier to a <code class="code">gnutls_gost_paramset_t</code>  value.
</p>
<p><strong class="strong">Returns:</strong> a <code class="code">gnutls_gost_paramset_get_oid</code>  of the specified GOST 28147
param st, or <code class="code">GNUTLS_GOST_PARAMSET_UNKNOWN</code>  on failure.
</p>
<p><strong class="strong">Since:</strong> 3.6.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005foid_005fto_005fmac-1"><span>gnutls_oid_to_mac<a class="copiable-link" href="#gnutls_005foid_005fto_005fmac-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005foid_005fto_005fmac"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005foid_005fto_005fmac"><span class="category-def">Function: </span><span><code class="def-type">gnutls_mac_algorithm_t</code> <strong class="def-name">gnutls_oid_to_mac</strong> <code class="def-code-arguments">(const char * <var class="var">oid</var>)</code><a class="copiable-link" href="#index-gnutls_005foid_005fto_005fmac"> &para;</a></span></dt>
<dd><p><var class="var">oid</var>: is an object identifier
</p>
<p>Converts a textual object identifier typically from PKCS<code class="code">5</code>  values to a <code class="code">gnutls_mac_algorithm_t</code>  value.
</p>
<p><strong class="strong">Returns:</strong> a <code class="code">gnutls_mac_algorithm_t</code>  id of the specified digest
algorithm, or <code class="code">GNUTLS_MAC_UNKNOWN</code>  on failure.
</p>
<p><strong class="strong">Since:</strong> 3.5.4
</p></dd></dl>

<h4 class="subheading" id="gnutls_005foid_005fto_005fpk-1"><span>gnutls_oid_to_pk<a class="copiable-link" href="#gnutls_005foid_005fto_005fpk-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005foid_005fto_005fpk"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005foid_005fto_005fpk"><span class="category-def">Function: </span><span><code class="def-type">gnutls_pk_algorithm_t</code> <strong class="def-name">gnutls_oid_to_pk</strong> <code class="def-code-arguments">(const char * <var class="var">oid</var>)</code><a class="copiable-link" href="#index-gnutls_005foid_005fto_005fpk"> &para;</a></span></dt>
<dd><p><var class="var">oid</var>: is an object identifier
</p>
<p>Converts a textual object identifier to a <code class="code">gnutls_pk_algorithm_t</code>  value.
</p>
<p><strong class="strong">Returns:</strong> a <code class="code">gnutls_pk_algorithm_t</code>  id of the specified digest
algorithm, or <code class="code">GNUTLS_PK_UNKNOWN</code>  on failure.
</p>
<p><strong class="strong">Since:</strong> 3.4.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005foid_005fto_005fsign-1"><span>gnutls_oid_to_sign<a class="copiable-link" href="#gnutls_005foid_005fto_005fsign-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005foid_005fto_005fsign"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005foid_005fto_005fsign"><span class="category-def">Function: </span><span><code class="def-type">gnutls_sign_algorithm_t</code> <strong class="def-name">gnutls_oid_to_sign</strong> <code class="def-code-arguments">(const char * <var class="var">oid</var>)</code><a class="copiable-link" href="#index-gnutls_005foid_005fto_005fsign"> &para;</a></span></dt>
<dd><p><var class="var">oid</var>: is an object identifier
</p>
<p>Converts a textual object identifier to a <code class="code">gnutls_sign_algorithm_t</code>  value.
</p>
<p><strong class="strong">Returns:</strong> a <code class="code">gnutls_sign_algorithm_t</code>  id of the specified digest
algorithm, or <code class="code">GNUTLS_SIGN_UNKNOWN</code>  on failure.
</p>
<p><strong class="strong">Since:</strong> 3.4.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fopenpgp_005fsend_005fcert-1"><span>gnutls_openpgp_send_cert<a class="copiable-link" href="#gnutls_005fopenpgp_005fsend_005fcert-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fopenpgp_005fsend_005fcert"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fopenpgp_005fsend_005fcert"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_openpgp_send_cert</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_openpgp_crt_status_t <var class="var">status</var>)</code><a class="copiable-link" href="#index-gnutls_005fopenpgp_005fsend_005fcert"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a gnutls session
</p>
<p><var class="var">status</var>: is ignored
</p>
<p>This function is no-op.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_UNIMPLEMENTED_FEATURE</code> .
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpacket_005fdeinit-1"><span>gnutls_packet_deinit<a class="copiable-link" href="#gnutls_005fpacket_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpacket_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpacket_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_packet_deinit</strong> <code class="def-code-arguments">(gnutls_packet_t <var class="var">packet</var>)</code><a class="copiable-link" href="#index-gnutls_005fpacket_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">packet</var>: is a pointer to a <code class="code">gnutls_packet_st</code>  structure.
</p>
<p>This function will deinitialize all data associated with
the received packet.
</p>
<p><strong class="strong">Since:</strong> 3.3.5
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpacket_005fget-1"><span>gnutls_packet_get<a class="copiable-link" href="#gnutls_005fpacket_005fget-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpacket_005fget"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpacket_005fget"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_packet_get</strong> <code class="def-code-arguments">(gnutls_packet_t <var class="var">packet</var>, gnutls_datum_t * <var class="var">data</var>, unsigned char * <var class="var">sequence</var>)</code><a class="copiable-link" href="#index-gnutls_005fpacket_005fget"> &para;</a></span></dt>
<dd><p><var class="var">packet</var>: is a <code class="code">gnutls_packet_t</code>  type.
</p>
<p><var class="var">data</var>: will contain the data present in the  <code class="code">packet</code> structure (may be <code class="code">NULL</code> )
</p>
<p><var class="var">sequence</var>: the 8-bytes of the packet sequence number (may be <code class="code">NULL</code> )
</p>
<p>This function returns the data and sequence number associated with
the received packet.
</p>
<p><strong class="strong">Since:</strong> 3.3.5
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpem_005fbase64_005fdecode-1"><span>gnutls_pem_base64_decode<a class="copiable-link" href="#gnutls_005fpem_005fbase64_005fdecode-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpem_005fbase64_005fdecode"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpem_005fbase64_005fdecode"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pem_base64_decode</strong> <code class="def-code-arguments">(const char * <var class="var">header</var>, const gnutls_datum_t * <var class="var">b64_data</var>, unsigned char * <var class="var">result</var>, size_t * <var class="var">result_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fpem_005fbase64_005fdecode"> &para;</a></span></dt>
<dd><p><var class="var">header</var>: A null terminated string with the PEM header (eg. CERTIFICATE)
</p>
<p><var class="var">b64_data</var>: contain the encoded data
</p>
<p><var class="var">result</var>: the place where decoded data will be copied
</p>
<p><var class="var">result_size</var>: holds the size of the result
</p>
<p>This function will decode the given encoded data.  If the header
given is non <code class="code">NULL</code>  this function will search for &quot;&mdash;&ndash;BEGIN header&quot;
and decode only this part.  Otherwise it will decode the first PEM
packet found.
</p>
<p><strong class="strong">Returns:</strong> On success <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
<code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  is returned if the buffer given is
not long enough, or 0 on success.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpem_005fbase64_005fdecode2-1"><span>gnutls_pem_base64_decode2<a class="copiable-link" href="#gnutls_005fpem_005fbase64_005fdecode2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpem_005fbase64_005fdecode2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpem_005fbase64_005fdecode2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pem_base64_decode2</strong> <code class="def-code-arguments">(const char * <var class="var">header</var>, const gnutls_datum_t * <var class="var">b64_data</var>, gnutls_datum_t * <var class="var">result</var>)</code><a class="copiable-link" href="#index-gnutls_005fpem_005fbase64_005fdecode2"> &para;</a></span></dt>
<dd><p><var class="var">header</var>: The PEM header (eg. CERTIFICATE)
</p>
<p><var class="var">b64_data</var>: contains the encoded data
</p>
<p><var class="var">result</var>: the location of decoded data
</p>
<p>This function will decode the given encoded data. The decoded data
will be allocated, and stored into result.  If the header given is
non null this function will search for &quot;&mdash;&ndash;BEGIN header&quot; and
decode only this part. Otherwise it will decode the first PEM
packet found.
</p>
<p>You should use <code class="code">gnutls_free()</code>  to free the returned data.
</p>
<p>Note, that prior to GnuTLS 3.4.0 this function was available
under the name <code class="code">gnutls_pem_base64_decode_alloc()</code> . There is
compatibility macro pointing to this function.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise
an error code is returned.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpem_005fbase64_005fencode-1"><span>gnutls_pem_base64_encode<a class="copiable-link" href="#gnutls_005fpem_005fbase64_005fencode-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpem_005fbase64_005fencode"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpem_005fbase64_005fencode"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pem_base64_encode</strong> <code class="def-code-arguments">(const char * <var class="var">msg</var>, const gnutls_datum_t * <var class="var">data</var>, char * <var class="var">result</var>, size_t * <var class="var">result_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fpem_005fbase64_005fencode"> &para;</a></span></dt>
<dd><p><var class="var">msg</var>: is a message to be put in the header (may be <code class="code">NULL</code> )
</p>
<p><var class="var">data</var>: contain the raw data
</p>
<p><var class="var">result</var>: the place where base64 data will be copied
</p>
<p><var class="var">result_size</var>: holds the size of the result
</p>
<p>This function will convert the given data to printable data, using
the base64 encoding. This is the encoding used in PEM messages.
</p>
<p>The output string will be null terminated, although the output size will
not include the terminating null.
</p>
<p><strong class="strong">Returns:</strong> On success <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
<code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  is returned if the buffer given is
not long enough, or 0 on success.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpem_005fbase64_005fencode2-1"><span>gnutls_pem_base64_encode2<a class="copiable-link" href="#gnutls_005fpem_005fbase64_005fencode2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpem_005fbase64_005fencode2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpem_005fbase64_005fencode2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pem_base64_encode2</strong> <code class="def-code-arguments">(const char * <var class="var">header</var>, const gnutls_datum_t * <var class="var">data</var>, gnutls_datum_t * <var class="var">result</var>)</code><a class="copiable-link" href="#index-gnutls_005fpem_005fbase64_005fencode2"> &para;</a></span></dt>
<dd><p><var class="var">header</var>: is a message to be put in the encoded header (may be <code class="code">NULL</code> )
</p>
<p><var class="var">data</var>: contains the raw data
</p>
<p><var class="var">result</var>: will hold the newly allocated encoded data
</p>
<p>This function will convert the given data to printable data, using
the base64 encoding.  This is the encoding used in PEM messages.
This function will allocate the required memory to hold the encoded
data.
</p>
<p>You should use <code class="code">gnutls_free()</code>  to free the returned data.
</p>
<p>Note, that prior to GnuTLS 3.4.0 this function was available
under the name <code class="code">gnutls_pem_base64_encode_alloc()</code> . There is
compatibility macro pointing to this function.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise
an error code is returned.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fperror-1"><span>gnutls_perror<a class="copiable-link" href="#gnutls_005fperror-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fperror"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fperror"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_perror</strong> <code class="def-code-arguments">(int <var class="var">error</var>)</code><a class="copiable-link" href="#index-gnutls_005fperror"> &para;</a></span></dt>
<dd><p><var class="var">error</var>: is a GnuTLS error code, a negative error code
</p>
<p>This function is like <code class="code">perror()</code> . The only difference is that it
accepts an error number returned by a gnutls function.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpk_005falgorithm_005fget_005fname-1"><span>gnutls_pk_algorithm_get_name<a class="copiable-link" href="#gnutls_005fpk_005falgorithm_005fget_005fname-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpk_005falgorithm_005fget_005fname"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpk_005falgorithm_005fget_005fname"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_pk_algorithm_get_name</strong> <code class="def-code-arguments">(gnutls_pk_algorithm_t <var class="var">algorithm</var>)</code><a class="copiable-link" href="#index-gnutls_005fpk_005falgorithm_005fget_005fname"> &para;</a></span></dt>
<dd><p><var class="var">algorithm</var>: is a pk algorithm
</p>
<p>Convert a <code class="code">gnutls_pk_algorithm_t</code>  value to a string.
</p>
<p><strong class="strong">Returns:</strong> a string that contains the name of the specified public
key algorithm, or <code class="code">NULL</code> .
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpk_005fbits_005fto_005fsec_005fparam-1"><span>gnutls_pk_bits_to_sec_param<a class="copiable-link" href="#gnutls_005fpk_005fbits_005fto_005fsec_005fparam-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpk_005fbits_005fto_005fsec_005fparam"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpk_005fbits_005fto_005fsec_005fparam-1"><span class="category-def">Function: </span><span><code class="def-type">gnutls_sec_param_t</code> <strong class="def-name">gnutls_pk_bits_to_sec_param</strong> <code class="def-code-arguments">(gnutls_pk_algorithm_t <var class="var">algo</var>, unsigned int <var class="var">bits</var>)</code><a class="copiable-link" href="#index-gnutls_005fpk_005fbits_005fto_005fsec_005fparam-1"> &para;</a></span></dt>
<dd><p><var class="var">algo</var>: is a public key algorithm
</p>
<p><var class="var">bits</var>: is the number of bits
</p>
<p>This is the inverse of <code class="code">gnutls_sec_param_to_pk_bits()</code> . Given an algorithm
and the number of bits, it will return the security parameter. This is
a rough indication.
</p>
<p><strong class="strong">Returns:</strong> The security parameter.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpk_005fget_005fid-1"><span>gnutls_pk_get_id<a class="copiable-link" href="#gnutls_005fpk_005fget_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpk_005fget_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpk_005fget_005fid"><span class="category-def">Function: </span><span><code class="def-type">gnutls_pk_algorithm_t</code> <strong class="def-name">gnutls_pk_get_id</strong> <code class="def-code-arguments">(const char * <var class="var">name</var>)</code><a class="copiable-link" href="#index-gnutls_005fpk_005fget_005fid"> &para;</a></span></dt>
<dd><p><var class="var">name</var>: is a string containing a public key algorithm name.
</p>
<p>Convert a string to a <code class="code">gnutls_pk_algorithm_t</code>  value.  The names are
compared in a case insensitive way.  For example,
gnutls_pk_get_id(&quot;RSA&quot;) will return <code class="code">GNUTLS_PK_RSA</code> .
</p>
<p><strong class="strong">Returns:</strong> a <code class="code">gnutls_pk_algorithm_t</code>  id of the specified public key
algorithm string, or <code class="code">GNUTLS_PK_UNKNOWN</code>  on failures.
</p>
<p><strong class="strong">Since:</strong> 2.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpk_005fget_005fname-1"><span>gnutls_pk_get_name<a class="copiable-link" href="#gnutls_005fpk_005fget_005fname-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpk_005fget_005fname"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpk_005fget_005fname"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_pk_get_name</strong> <code class="def-code-arguments">(gnutls_pk_algorithm_t <var class="var">algorithm</var>)</code><a class="copiable-link" href="#index-gnutls_005fpk_005fget_005fname"> &para;</a></span></dt>
<dd><p><var class="var">algorithm</var>: is a public key algorithm
</p>
<p>Convert a <code class="code">gnutls_pk_algorithm_t</code>  value to a string.
</p>
<p><strong class="strong">Returns:</strong> a pointer to a string that contains the name of the
specified public key algorithm, or <code class="code">NULL</code> .
</p>
<p><strong class="strong">Since:</strong> 2.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpk_005fget_005foid-1"><span>gnutls_pk_get_oid<a class="copiable-link" href="#gnutls_005fpk_005fget_005foid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpk_005fget_005foid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpk_005fget_005foid"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_pk_get_oid</strong> <code class="def-code-arguments">(gnutls_pk_algorithm_t <var class="var">algorithm</var>)</code><a class="copiable-link" href="#index-gnutls_005fpk_005fget_005foid"> &para;</a></span></dt>
<dd><p><var class="var">algorithm</var>: is a public key algorithm
</p>
<p>Convert a <code class="code">gnutls_pk_algorithm_t</code>  value to its object identifier string.
</p>
<p><strong class="strong">Returns:</strong> a pointer to a string that contains the object identifier of the
specified public key algorithm, or <code class="code">NULL</code> .
</p>
<p><strong class="strong">Since:</strong> 3.4.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpk_005flist-1"><span>gnutls_pk_list<a class="copiable-link" href="#gnutls_005fpk_005flist-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpk_005flist"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpk_005flist"><span class="category-def">Function: </span><span><code class="def-type">const gnutls_pk_algorithm_t *</code> <strong class="def-name">gnutls_pk_list</strong> <code class="def-code-arguments">( <var class="var">void</var>)</code><a class="copiable-link" href="#index-gnutls_005fpk_005flist"> &para;</a></span></dt>
<dd>
<p>Get a list of supported public key algorithms.
</p>
<p>This function is not thread safe.
</p>
<p><strong class="strong">Returns:</strong> a (0)-terminated list of <code class="code">gnutls_pk_algorithm_t</code>  integers
indicating the available ciphers.
</p>
<p><strong class="strong">Since:</strong> 2.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpk_005fto_005fsign-1"><span>gnutls_pk_to_sign<a class="copiable-link" href="#gnutls_005fpk_005fto_005fsign-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpk_005fto_005fsign"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpk_005fto_005fsign"><span class="category-def">Function: </span><span><code class="def-type">gnutls_sign_algorithm_t</code> <strong class="def-name">gnutls_pk_to_sign</strong> <code class="def-code-arguments">(gnutls_pk_algorithm_t <var class="var">pk</var>, gnutls_digest_algorithm_t <var class="var">hash</var>)</code><a class="copiable-link" href="#index-gnutls_005fpk_005fto_005fsign"> &para;</a></span></dt>
<dd><p><var class="var">pk</var>: is a public key algorithm
</p>
<p><var class="var">hash</var>: a hash algorithm
</p>
<p>This function maps public key and hash algorithms combinations
to signature algorithms.
</p>
<p><strong class="strong">Returns:</strong> return a <code class="code">gnutls_sign_algorithm_t</code>  value, or <code class="code">GNUTLS_SIGN_UNKNOWN</code>  on error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprf-1"><span>gnutls_prf<a class="copiable-link" href="#gnutls_005fprf-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprf"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprf"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_prf</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, size_t <var class="var">label_size</var>, const char * <var class="var">label</var>, int <var class="var">server_random_first</var>, size_t <var class="var">extra_size</var>, const char * <var class="var">extra</var>, size_t <var class="var">outsize</var>, char * <var class="var">out</var>)</code><a class="copiable-link" href="#index-gnutls_005fprf"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">label_size</var>: length of the  <code class="code">label</code> variable.
</p>
<p><var class="var">label</var>: label used in PRF computation, typically a short string.
</p>
<p><var class="var">server_random_first</var>: non-zero if server random field should be first in seed
</p>
<p><var class="var">extra_size</var>: length of the  <code class="code">extra</code> variable.
</p>
<p><var class="var">extra</var>: optional extra data to seed the PRF with.
</p>
<p><var class="var">outsize</var>: size of pre-allocated output buffer to hold the output.
</p>
<p><var class="var">out</var>: pre-allocated buffer to hold the generated data.
</p>
<p>Applies the TLS Pseudo-Random-Function (PRF) on the master secret
and the provided data, seeded with the client and server random fields.
For the key expansion specified in RFC5705 see <code class="code">gnutls_prf_rfc5705()</code> .
</p>
<p>The  <code class="code">label</code> variable usually contains a string denoting the purpose
for the generated data.  The  <code class="code">server_random_first</code> indicates whether
the client random field or the server random field should be first
in the seed.  Non-zero indicates that the server random field is first,
0 that the client random field is first.
</p>
<p>The  <code class="code">extra</code> variable can be used to add more data to the seed, after
the random variables.  It can be used to make sure the
generated output is strongly connected to some additional data
(e.g., a string used in user authentication).
</p>
<p>The output is placed in  <code class="code">out</code> , which must be pre-allocated.
</p>
<p><strong class="strong">Note:</strong> This function produces identical output with <code class="code">gnutls_prf_rfc5705()</code> 
when  <code class="code">server_random_first</code> is set to 0 and  <code class="code">extra</code> is <code class="code">NULL</code> . Under TLS1.3
this function will only operate when these conditions are true, or otherwise
return <code class="code">GNUTLS_E_INVALID_REQUEST</code> .
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, or an error code.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprf_005fearly-1"><span>gnutls_prf_early<a class="copiable-link" href="#gnutls_005fprf_005fearly-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprf_005fearly"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprf_005fearly"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_prf_early</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, size_t <var class="var">label_size</var>, const char * <var class="var">label</var>, size_t <var class="var">context_size</var>, const char * <var class="var">context</var>, size_t <var class="var">outsize</var>, char * <var class="var">out</var>)</code><a class="copiable-link" href="#index-gnutls_005fprf_005fearly"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">label_size</var>: length of the  <code class="code">label</code> variable.
</p>
<p><var class="var">label</var>: label used in PRF computation, typically a short string.
</p>
<p><var class="var">context_size</var>: length of the  <code class="code">extra</code> variable.
</p>
<p><var class="var">context</var>: optional extra data to seed the PRF with.
</p>
<p><var class="var">outsize</var>: size of pre-allocated output buffer to hold the output.
</p>
<p><var class="var">out</var>: pre-allocated buffer to hold the generated data.
</p>
<p>This function is similar to <code class="code">gnutls_prf_rfc5705()</code> , but only works in
TLS 1.3 or later to export early keying material.
</p>
<p>Note that the keying material is only available after the
ClientHello message is processed and before the application traffic
keys are established.  Therefore this function shall be called in a
handshake hook function for <code class="code">GNUTLS_HANDSHAKE_CLIENT_HELLO</code> .
</p>
<p>The  <code class="code">label</code> variable usually contains a string denoting the purpose
for the generated data.
</p>
<p>The  <code class="code">context</code> variable can be used to add more data to the seed, after
the random variables.  It can be used to make sure the
generated output is strongly connected to some additional data
(e.g., a string used in user authentication).
</p>
<p>The output is placed in  <code class="code">out</code> , which must be pre-allocated.
</p>
<p>Note that, to provide the RFC5705 context, the  <code class="code">context</code> variable
must be non-null.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, or an error code.
</p>
<p><strong class="strong">Since:</strong> 3.6.8
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprf_005fhash_005fget-1"><span>gnutls_prf_hash_get<a class="copiable-link" href="#gnutls_005fprf_005fhash_005fget-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprf_005fhash_005fget"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprf_005fhash_005fget"><span class="category-def">Function: </span><span><code class="def-type">gnutls_digest_algorithm_t</code> <strong class="def-name">gnutls_prf_hash_get</strong> <code class="def-code-arguments">(const gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fprf_005fhash_005fget"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>Get the currently used hash algorithm. In TLS 1.3, the hash
algorithm is used for both the key derivation function and
handshake message authentication code. In TLS 1.2, it matches the
hash algorithm used for PRF.
</p>
<p><strong class="strong">Returns:</strong> the currently used hash algorithm, a
<code class="code">gnutls_digest_algorithm_t</code>  value.
</p>
<p><strong class="strong">Since:</strong> 3.6.13
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprf_005fraw-1"><span>gnutls_prf_raw<a class="copiable-link" href="#gnutls_005fprf_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprf_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprf_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_prf_raw</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, size_t <var class="var">label_size</var>, const char * <var class="var">label</var>, size_t <var class="var">seed_size</var>, const char * <var class="var">seed</var>, size_t <var class="var">outsize</var>, char * <var class="var">out</var>)</code><a class="copiable-link" href="#index-gnutls_005fprf_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">label_size</var>: length of the  <code class="code">label</code> variable.
</p>
<p><var class="var">label</var>: label used in PRF computation, typically a short string.
</p>
<p><var class="var">seed_size</var>: length of the  <code class="code">seed</code> variable.
</p>
<p><var class="var">seed</var>: optional extra data to seed the PRF with.
</p>
<p><var class="var">outsize</var>: size of pre-allocated output buffer to hold the output.
</p>
<p><var class="var">out</var>: pre-allocated buffer to hold the generated data.
</p>
<p>Apply the TLS Pseudo-Random-Function (PRF) on the master secret
and the provided data.
</p>
<p>The  <code class="code">label</code> variable usually contains a string denoting the purpose
for the generated data.  The  <code class="code">seed</code> usually contains data such as the
client and server random, perhaps together with some additional
data that is added to guarantee uniqueness of the output for a
particular purpose.
</p>
<p>Because the output is not guaranteed to be unique for a particular
session unless  <code class="code">seed</code> includes the client random and server random
fields (the PRF would output the same data on another connection
resumed from the first one), it is not recommended to use this
function directly.  The <code class="code">gnutls_prf()</code>  function seeds the PRF with the
client and server random fields directly, and is recommended if you
want to generate pseudo random data unique for each session.
</p>
<p><strong class="strong">Note:</strong> This function will only operate under TLS versions prior to 1.3.
In TLS1.3 the use of PRF is replaced with HKDF and the generic
exporters like <code class="code">gnutls_prf_rfc5705()</code>  should be used instead. Under
TLS1.3 this function returns <code class="code">GNUTLS_E_INVALID_REQUEST</code> .
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, or an error code.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprf_005frfc5705-1"><span>gnutls_prf_rfc5705<a class="copiable-link" href="#gnutls_005fprf_005frfc5705-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprf_005frfc5705"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprf_005frfc5705-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_prf_rfc5705</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, size_t <var class="var">label_size</var>, const char * <var class="var">label</var>, size_t <var class="var">context_size</var>, const char * <var class="var">context</var>, size_t <var class="var">outsize</var>, char * <var class="var">out</var>)</code><a class="copiable-link" href="#index-gnutls_005fprf_005frfc5705-1"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">label_size</var>: length of the  <code class="code">label</code> variable.
</p>
<p><var class="var">label</var>: label used in PRF computation, typically a short string.
</p>
<p><var class="var">context_size</var>: length of the  <code class="code">extra</code> variable.
</p>
<p><var class="var">context</var>: optional extra data to seed the PRF with.
</p>
<p><var class="var">outsize</var>: size of pre-allocated output buffer to hold the output.
</p>
<p><var class="var">out</var>: pre-allocated buffer to hold the generated data.
</p>
<p>Exports keying material from TLS/DTLS session to an application, as
specified in RFC5705.
</p>
<p>In the TLS versions prior to 1.3, it applies the TLS
Pseudo-Random-Function (PRF) on the master secret and the provided
data, seeded with the client and server random fields.
</p>
<p>In TLS 1.3, it applies HKDF on the exporter master secret derived
from the master secret.
</p>
<p>The  <code class="code">label</code> variable usually contains a string denoting the purpose
for the generated data.
</p>
<p>The  <code class="code">context</code> variable can be used to add more data to the seed, after
the random variables.  It can be used to make sure the
generated output is strongly connected to some additional data
(e.g., a string used in user authentication). 
</p>
<p>The output is placed in  <code class="code">out</code> , which must be pre-allocated.
</p>
<p>Note that, to provide the RFC5705 context, the  <code class="code">context</code> variable
must be non-null.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, or an error code.
</p>
<p><strong class="strong">Since:</strong> 3.4.4
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpriority_005fcertificate_005ftype_005flist-1"><span>gnutls_priority_certificate_type_list<a class="copiable-link" href="#gnutls_005fpriority_005fcertificate_005ftype_005flist-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpriority_005fcertificate_005ftype_005flist"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpriority_005fcertificate_005ftype_005flist"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_priority_certificate_type_list</strong> <code class="def-code-arguments">(gnutls_priority_t <var class="var">pcache</var>, const unsigned int ** <var class="var">list</var>)</code><a class="copiable-link" href="#index-gnutls_005fpriority_005fcertificate_005ftype_005flist"> &para;</a></span></dt>
<dd><p><var class="var">pcache</var>: is a <code class="code">gnutls_priority_t</code>  type.
</p>
<p><var class="var">list</var>: will point to an integer list
</p>
<p>Get a list of available certificate types in the priority
structure.
</p>
<p>As of version 3.6.4 this function is an alias for
gnutls_priority_certificate_type_list2 with the target parameter
set to:
- GNUTLS_CTYPE_SERVER, if the <code class="code">SERVER_PRECEDENCE</code>  option is set
- GNUTLS_CTYPE_CLIENT, otherwise.
</p>
<p><strong class="strong">Returns:</strong> the number of certificate types, or an error code.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpriority_005fcertificate_005ftype_005flist2-1"><span>gnutls_priority_certificate_type_list2<a class="copiable-link" href="#gnutls_005fpriority_005fcertificate_005ftype_005flist2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpriority_005fcertificate_005ftype_005flist2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpriority_005fcertificate_005ftype_005flist2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_priority_certificate_type_list2</strong> <code class="def-code-arguments">(gnutls_priority_t <var class="var">pcache</var>, const unsigned int ** <var class="var">list</var>, gnutls_ctype_target_t <var class="var">target</var>)</code><a class="copiable-link" href="#index-gnutls_005fpriority_005fcertificate_005ftype_005flist2"> &para;</a></span></dt>
<dd><p><var class="var">pcache</var>: is a <code class="code">gnutls_priority_t</code>  type.
</p>
<p><var class="var">list</var>: will point to an integer list.
</p>
<p><var class="var">target</var>: is a <code class="code">gnutls_ctype_target_t</code>  type. Valid arguments are
GNUTLS_CTYPE_CLIENT and GNUTLS_CTYPE_SERVER
</p>
<p>Get a list of available certificate types for the given target
in the priority structure.
</p>
<p><strong class="strong">Returns:</strong> the number of certificate types, or an error code.
</p>
<p><strong class="strong">Since:</strong> 3.6.4
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpriority_005fcipher_005flist-1"><span>gnutls_priority_cipher_list<a class="copiable-link" href="#gnutls_005fpriority_005fcipher_005flist-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpriority_005fcipher_005flist"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpriority_005fcipher_005flist"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_priority_cipher_list</strong> <code class="def-code-arguments">(gnutls_priority_t <var class="var">pcache</var>, const unsigned int ** <var class="var">list</var>)</code><a class="copiable-link" href="#index-gnutls_005fpriority_005fcipher_005flist"> &para;</a></span></dt>
<dd><p><var class="var">pcache</var>: is a <code class="code">gnutls_priority_t</code>  type.
</p>
<p><var class="var">list</var>: will point to an integer list
</p>
<p>Get a list of available ciphers in the priority
structure.
</p>
<p><strong class="strong">Returns:</strong> the number of items, or an error code.
</p>
<p><strong class="strong">Since:</strong> 3.2.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpriority_005fdeinit-1"><span>gnutls_priority_deinit<a class="copiable-link" href="#gnutls_005fpriority_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpriority_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpriority_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_priority_deinit</strong> <code class="def-code-arguments">(gnutls_priority_t <var class="var">priority_cache</var>)</code><a class="copiable-link" href="#index-gnutls_005fpriority_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">priority_cache</var>: is a <code class="code">gnutls_priority_t</code>  type.
</p>
<p>Deinitializes the priority cache.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpriority_005fecc_005fcurve_005flist-1"><span>gnutls_priority_ecc_curve_list<a class="copiable-link" href="#gnutls_005fpriority_005fecc_005fcurve_005flist-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpriority_005fecc_005fcurve_005flist"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpriority_005fecc_005fcurve_005flist"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_priority_ecc_curve_list</strong> <code class="def-code-arguments">(gnutls_priority_t <var class="var">pcache</var>, const unsigned int ** <var class="var">list</var>)</code><a class="copiable-link" href="#index-gnutls_005fpriority_005fecc_005fcurve_005flist"> &para;</a></span></dt>
<dd><p><var class="var">pcache</var>: is a <code class="code">gnutls_priority_t</code>  type.
</p>
<p><var class="var">list</var>: will point to an integer list
</p>
<p>Get a list of available elliptic curves in the priority
structure.
</p>
<p><strong class="strong">Deprecated:</strong> This function has been replaced by
<code class="code">gnutls_priority_group_list()</code>  since 3.6.0.
</p>
<p><strong class="strong">Returns:</strong> the number of items, or an error code.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpriority_005fget_005fcipher_005fsuite_005findex-1"><span>gnutls_priority_get_cipher_suite_index<a class="copiable-link" href="#gnutls_005fpriority_005fget_005fcipher_005fsuite_005findex-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpriority_005fget_005fcipher_005fsuite_005findex"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpriority_005fget_005fcipher_005fsuite_005findex"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_priority_get_cipher_suite_index</strong> <code class="def-code-arguments">(gnutls_priority_t <var class="var">pcache</var>, unsigned int <var class="var">idx</var>, unsigned int * <var class="var">sidx</var>)</code><a class="copiable-link" href="#index-gnutls_005fpriority_005fget_005fcipher_005fsuite_005findex"> &para;</a></span></dt>
<dd><p><var class="var">pcache</var>: is a <code class="code">gnutls_priority_t</code>  type.
</p>
<p><var class="var">idx</var>: is an index number.
</p>
<p><var class="var">sidx</var>: internal index of cipher suite to get information about.
</p>
<p>Provides the internal ciphersuite index to be used with
<code class="code">gnutls_cipher_suite_info()</code> . The index  <code class="code">idx</code> provided is an
index kept at the priorities structure. It might be that a valid
priorities index does not correspond to a ciphersuite and in
that case <code class="code">GNUTLS_E_UNKNOWN_CIPHER_SUITE</code>  will be returned.
Once the last available index is crossed then
<code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  will be returned.
</p>
<p><strong class="strong">Returns:</strong> On success it returns <code class="code">GNUTLS_E_SUCCESS</code>  (0), or a negative error value otherwise.
</p>
<p><strong class="strong">Since:</strong> 3.0.9
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpriority_005fgroup_005flist-1"><span>gnutls_priority_group_list<a class="copiable-link" href="#gnutls_005fpriority_005fgroup_005flist-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpriority_005fgroup_005flist"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpriority_005fgroup_005flist"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_priority_group_list</strong> <code class="def-code-arguments">(gnutls_priority_t <var class="var">pcache</var>, const unsigned int ** <var class="var">list</var>)</code><a class="copiable-link" href="#index-gnutls_005fpriority_005fgroup_005flist"> &para;</a></span></dt>
<dd><p><var class="var">pcache</var>: is a <code class="code">gnutls_priority_t</code>  type.
</p>
<p><var class="var">list</var>: will point to an integer list
</p>
<p>Get a list of available groups in the priority
structure.
</p>
<p><strong class="strong">Returns:</strong> the number of items, or an error code.
</p>
<p><strong class="strong">Since:</strong> 3.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpriority_005finit-1"><span>gnutls_priority_init<a class="copiable-link" href="#gnutls_005fpriority_005finit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpriority_005finit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpriority_005finit"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_priority_init</strong> <code class="def-code-arguments">(gnutls_priority_t * <var class="var">priority_cache</var>, const char * <var class="var">priorities</var>, const char ** <var class="var">err_pos</var>)</code><a class="copiable-link" href="#index-gnutls_005fpriority_005finit"> &para;</a></span></dt>
<dd><p><var class="var">priority_cache</var>: is a <code class="code">gnutls_priority_t</code>  type.
</p>
<p><var class="var">priorities</var>: is a string describing priorities (may be <code class="code">NULL</code> )
</p>
<p><var class="var">err_pos</var>: In case of an error this will have the position in the string the error occurred
</p>
<p>For applications that do not modify their crypto settings per release, consider
using <code class="code">gnutls_priority_init2()</code>  with <code class="code">GNUTLS_PRIORITY_INIT_DEF_APPEND</code>  flag
instead. We suggest to use centralized crypto settings handled by the GnuTLS
library, and applications modifying the default settings to their needs.
</p>
<p>This function is identical to <code class="code">gnutls_priority_init2()</code>  with zero
flags.
</p>
<p>A <code class="code">NULL</code>   <code class="code">priorities</code> string indicates the default priorities to be
used (this is available since GnuTLS 3.3.0).
</p>
<p><strong class="strong">Returns:</strong> On syntax error <code class="code">GNUTLS_E_INVALID_REQUEST</code>  is returned,
<code class="code">GNUTLS_E_SUCCESS</code>  on success, or an error code.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpriority_005finit2-1"><span>gnutls_priority_init2<a class="copiable-link" href="#gnutls_005fpriority_005finit2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpriority_005finit2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpriority_005finit2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_priority_init2</strong> <code class="def-code-arguments">(gnutls_priority_t * <var class="var">priority_cache</var>, const char * <var class="var">priorities</var>, const char ** <var class="var">err_pos</var>, unsigned <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpriority_005finit2"> &para;</a></span></dt>
<dd><p><var class="var">priority_cache</var>: is a <code class="code">gnutls_priority_t</code>  type.
</p>
<p><var class="var">priorities</var>: is a string describing priorities (may be <code class="code">NULL</code> )
</p>
<p><var class="var">err_pos</var>: In case of an error this will have the position in the string the error occurred
</p>
<p><var class="var">flags</var>: zero or <code class="code">GNUTLS_PRIORITY_INIT_DEF_APPEND</code> 
</p>
<p>Sets priorities for the ciphers, key exchange methods, and macs.
The  <code class="code">priority_cache</code> should be deinitialized
using <code class="code">gnutls_priority_deinit()</code> .
</p>
<p>The <code class="code">priorities</code>  option allows you to specify a colon
separated list of the cipher priorities to enable.
Some keywords are defined to provide quick access
to common preferences.
</p>
<p>When  <code class="code">flags</code> is set to <code class="code">GNUTLS_PRIORITY_INIT_DEF_APPEND</code>  then the  <code class="code">priorities</code> specified will be appended to the default options.
</p>
<p>Unless there is a special need, use the &quot;NORMAL&quot; keyword to
apply a reasonable security level, or &quot;NORMAL:%COMPAT&quot; for compatibility.
</p>
<p>&quot;PERFORMANCE&quot; means all the &quot;secure&quot; ciphersuites are enabled,
limited to 128 bit ciphers and sorted by terms of speed
performance.
</p>
<p>&quot;LEGACY&quot; the NORMAL settings for GnuTLS 3.2.x or earlier. There is
no verification profile set, and the allowed DH primes are considered
weak today.
</p>
<p>&quot;NORMAL&quot; means all &quot;secure&quot; ciphersuites. The 256-bit ciphers are
included as a fallback only.  The ciphers are sorted by security
margin.
</p>
<p>&quot;PFS&quot; means all &quot;secure&quot; ciphersuites that support perfect forward secrecy.
The 256-bit ciphers are included as a fallback only.
The ciphers are sorted by security margin.
</p>
<p>&quot;SECURE128&quot; means all &quot;secure&quot; ciphersuites of security level 128-bit
or more.
</p>
<p>&quot;SECURE192&quot; means all &quot;secure&quot; ciphersuites of security level 192-bit
or more.
</p>
<p>&quot;SUITEB128&quot; means all the NSA SuiteB ciphersuites with security level
of 128.
</p>
<p>&quot;SUITEB192&quot; means all the NSA SuiteB ciphersuites with security level
of 192.
</p>
<p>&quot;NONE&quot; means nothing is enabled.  This disables everything, including protocols.
</p>
<p>&quot;@KEYWORD1,KEYWORD2,...&quot; The system administrator imposed settings.
The provided keyword(s) will be expanded from a configuration-time
provided file - default is: /etc/gnutls/config.
Any attributes that follow it, will be appended to the expanded
string. If multiple keywords are provided, separated by commas,
then the first keyword that exists in the configuration file
will be used. At least one of the keywords must exist, or this
function will return an error. Typical usage would be to specify
an application specified keyword first, followed by &quot;SYSTEM&quot; as
a default fallback. e.g., &quot; <code class="code">LIBVIRT</code> ,SYSTEM:!-VERS-SSL3.0&quot; will
first try to find a config file entry matching &quot;LIBVIRT&quot;, but if
that does not exist will use the entry for &quot;SYSTEM&quot;. If &quot;SYSTEM&quot;
does not exist either, an error will be returned. In all cases,
the SSL3.0 protocol will be disabled. The system priority file
entries should be formatted as &quot;KEYWORD=VALUE&quot;, e.g.,
&quot;SYSTEM=NORMAL:+ARCFOUR-128&quot;.
</p>
<p>Special keywords are &quot;!&quot;, &quot;-&quot; and &quot;+&quot;.
&quot;!&quot; or &quot;-&quot; appended with an algorithm will remove this algorithm.
&quot;+&quot; appended with an algorithm will add this algorithm.
</p>
<p>Check the GnuTLS manual section &quot;Priority strings&quot; for detailed
information.
</p>
<p><strong class="strong">Examples:</strong> 
&quot;NONE:+VERS-TLS-ALL:+MAC-ALL:+RSA:+AES-128-CBC:+SIGN-ALL:+COMP-NULL&quot;
</p>
<p>&quot;NORMAL:+ARCFOUR-128&quot; means normal ciphers plus ARCFOUR-128.
</p>
<p>&quot;SECURE128:-VERS-SSL3.0&quot; means that only secure ciphers are
and enabled, SSL3.0 is disabled.
</p>
<p>&quot;NONE:+VERS-TLS-ALL:+AES-128-CBC:+RSA:+SHA1:+COMP-NULL:+SIGN-RSA-SHA1&quot;,
</p>
<p>&quot;NONE:+VERS-TLS-ALL:+AES-128-CBC:+ECDHE-RSA:+SHA1:+COMP-NULL:+SIGN-RSA-SHA1:+CURVE-SECP256R1&quot;,
</p>
<p>&quot;SECURE256:+SECURE128&quot;,
</p>
<p>Note that &quot;NORMAL:%COMPAT&quot; is the most compatible mode.
</p>
<p>A <code class="code">NULL</code>   <code class="code">priorities</code> string indicates the default priorities to be
used (this is available since GnuTLS 3.3.0).
</p>
<p><strong class="strong">Returns:</strong> On syntax error <code class="code">GNUTLS_E_INVALID_REQUEST</code>  is returned,
<code class="code">GNUTLS_E_SUCCESS</code>  on success, or an error code.
</p>
<p><strong class="strong">Since:</strong> 3.6.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpriority_005fkx_005flist-1"><span>gnutls_priority_kx_list<a class="copiable-link" href="#gnutls_005fpriority_005fkx_005flist-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpriority_005fkx_005flist"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpriority_005fkx_005flist"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_priority_kx_list</strong> <code class="def-code-arguments">(gnutls_priority_t <var class="var">pcache</var>, const unsigned int ** <var class="var">list</var>)</code><a class="copiable-link" href="#index-gnutls_005fpriority_005fkx_005flist"> &para;</a></span></dt>
<dd><p><var class="var">pcache</var>: is a <code class="code">gnutls_priority_t</code>  type.
</p>
<p><var class="var">list</var>: will point to an integer list
</p>
<p>Get a list of available key exchange methods in the priority
structure.
</p>
<p><strong class="strong">Returns:</strong> the number of items, or an error code.
</p>
<p><strong class="strong">Since:</strong> 3.2.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpriority_005fmac_005flist-1"><span>gnutls_priority_mac_list<a class="copiable-link" href="#gnutls_005fpriority_005fmac_005flist-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpriority_005fmac_005flist"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpriority_005fmac_005flist"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_priority_mac_list</strong> <code class="def-code-arguments">(gnutls_priority_t <var class="var">pcache</var>, const unsigned int ** <var class="var">list</var>)</code><a class="copiable-link" href="#index-gnutls_005fpriority_005fmac_005flist"> &para;</a></span></dt>
<dd><p><var class="var">pcache</var>: is a <code class="code">gnutls_priority_t</code>  type.
</p>
<p><var class="var">list</var>: will point to an integer list
</p>
<p>Get a list of available MAC algorithms in the priority
structure.
</p>
<p><strong class="strong">Returns:</strong> the number of items, or an error code.
</p>
<p><strong class="strong">Since:</strong> 3.2.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpriority_005fprotocol_005flist-1"><span>gnutls_priority_protocol_list<a class="copiable-link" href="#gnutls_005fpriority_005fprotocol_005flist-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpriority_005fprotocol_005flist"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpriority_005fprotocol_005flist"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_priority_protocol_list</strong> <code class="def-code-arguments">(gnutls_priority_t <var class="var">pcache</var>, const unsigned int ** <var class="var">list</var>)</code><a class="copiable-link" href="#index-gnutls_005fpriority_005fprotocol_005flist"> &para;</a></span></dt>
<dd><p><var class="var">pcache</var>: is a <code class="code">gnutls_priority_t</code>  type.
</p>
<p><var class="var">list</var>: will point to an integer list
</p>
<p>Get a list of available TLS version numbers in the priority
structure.
</p>
<p><strong class="strong">Returns:</strong> the number of protocols, or an error code.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpriority_005fset-1"><span>gnutls_priority_set<a class="copiable-link" href="#gnutls_005fpriority_005fset-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpriority_005fset"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpriority_005fset"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_priority_set</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_priority_t <var class="var">priority</var>)</code><a class="copiable-link" href="#index-gnutls_005fpriority_005fset"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">priority</var>: is a <code class="code">gnutls_priority_t</code>  type.
</p>
<p>Sets the priorities to use on the ciphers, key exchange methods,
and macs. Note that this function is expected to be called once
per session; when called multiple times (e.g., before a re-handshake,
the caller should make sure that any new settings are not incompatible
with the original session).
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, or an error code on error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpriority_005fset_005fdirect-1"><span>gnutls_priority_set_direct<a class="copiable-link" href="#gnutls_005fpriority_005fset_005fdirect-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpriority_005fset_005fdirect"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpriority_005fset_005fdirect"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_priority_set_direct</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, const char * <var class="var">priorities</var>, const char ** <var class="var">err_pos</var>)</code><a class="copiable-link" href="#index-gnutls_005fpriority_005fset_005fdirect"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">priorities</var>: is a string describing priorities
</p>
<p><var class="var">err_pos</var>: In case of an error this will have the position in the string the error occurred
</p>
<p>Sets the priorities to use on the ciphers, key exchange methods,
and macs.  This function avoids keeping a
priority cache and is used to directly set string priorities to a
TLS session.  For documentation check the <code class="code">gnutls_priority_init()</code> .
</p>
<p>To use a reasonable default, consider using <code class="code">gnutls_set_default_priority()</code> ,
or <code class="code">gnutls_set_default_priority_append()</code>  instead of this function.
</p>
<p><strong class="strong">Returns:</strong> On syntax error <code class="code">GNUTLS_E_INVALID_REQUEST</code>  is returned,
<code class="code">GNUTLS_E_SUCCESS</code>  on success, or an error code.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpriority_005fsign_005flist-1"><span>gnutls_priority_sign_list<a class="copiable-link" href="#gnutls_005fpriority_005fsign_005flist-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpriority_005fsign_005flist"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpriority_005fsign_005flist"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_priority_sign_list</strong> <code class="def-code-arguments">(gnutls_priority_t <var class="var">pcache</var>, const unsigned int ** <var class="var">list</var>)</code><a class="copiable-link" href="#index-gnutls_005fpriority_005fsign_005flist"> &para;</a></span></dt>
<dd><p><var class="var">pcache</var>: is a <code class="code">gnutls_priority_t</code>  type.
</p>
<p><var class="var">list</var>: will point to an integer list
</p>
<p>Get a list of available signature algorithms in the priority
structure.
</p>
<p><strong class="strong">Returns:</strong> the number of algorithms, or an error code.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpriority_005fstring_005flist-1"><span>gnutls_priority_string_list<a class="copiable-link" href="#gnutls_005fpriority_005fstring_005flist-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpriority_005fstring_005flist"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpriority_005fstring_005flist"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_priority_string_list</strong> <code class="def-code-arguments">(unsigned <var class="var">iter</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpriority_005fstring_005flist"> &para;</a></span></dt>
<dd><p><var class="var">iter</var>: an integer counter starting from zero
</p>
<p><var class="var">flags</var>: one of <code class="code">GNUTLS_PRIORITY_LIST_INIT_KEYWORDS</code> , <code class="code">GNUTLS_PRIORITY_LIST_SPECIAL</code> 
</p>
<p>Can be used to iterate all available priority strings.
Due to internal implementation details, there are cases where this
function can return the empty string. In that case that string should be ignored.
When no strings are available it returns <code class="code">NULL</code> .
</p>
<p><strong class="strong">Returns:</strong> a priority string
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprotocol_005fget_005fid-1"><span>gnutls_protocol_get_id<a class="copiable-link" href="#gnutls_005fprotocol_005fget_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprotocol_005fget_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprotocol_005fget_005fid"><span class="category-def">Function: </span><span><code class="def-type">gnutls_protocol_t</code> <strong class="def-name">gnutls_protocol_get_id</strong> <code class="def-code-arguments">(const char * <var class="var">name</var>)</code><a class="copiable-link" href="#index-gnutls_005fprotocol_005fget_005fid"> &para;</a></span></dt>
<dd><p><var class="var">name</var>: is a protocol name
</p>
<p>The names are compared in a case insensitive way.
</p>
<p><strong class="strong">Returns:</strong> an id of the specified protocol, or
<code class="code">GNUTLS_VERSION_UNKNOWN</code>  on error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprotocol_005fget_005fname-1"><span>gnutls_protocol_get_name<a class="copiable-link" href="#gnutls_005fprotocol_005fget_005fname-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprotocol_005fget_005fname"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprotocol_005fget_005fname"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_protocol_get_name</strong> <code class="def-code-arguments">(gnutls_protocol_t <var class="var">version</var>)</code><a class="copiable-link" href="#index-gnutls_005fprotocol_005fget_005fname"> &para;</a></span></dt>
<dd><p><var class="var">version</var>: is a (gnutls) version number
</p>
<p>Convert a <code class="code">gnutls_protocol_t</code>  value to a string.
</p>
<p><strong class="strong">Returns:</strong> a string that contains the name of the specified TLS
version (e.g., &quot;TLS1.0&quot;), or <code class="code">NULL</code> .
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprotocol_005fget_005fversion-1"><span>gnutls_protocol_get_version<a class="copiable-link" href="#gnutls_005fprotocol_005fget_005fversion-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprotocol_005fget_005fversion"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprotocol_005fget_005fversion"><span class="category-def">Function: </span><span><code class="def-type">gnutls_protocol_t</code> <strong class="def-name">gnutls_protocol_get_version</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fprotocol_005fget_005fversion"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>Get TLS version, a <code class="code">gnutls_protocol_t</code>  value.
</p>
<p><strong class="strong">Returns:</strong> The version of the currently used protocol.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprotocol_005flist-1"><span>gnutls_protocol_list<a class="copiable-link" href="#gnutls_005fprotocol_005flist-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprotocol_005flist"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprotocol_005flist"><span class="category-def">Function: </span><span><code class="def-type">const gnutls_protocol_t *</code> <strong class="def-name">gnutls_protocol_list</strong> <code class="def-code-arguments">( <var class="var">void</var>)</code><a class="copiable-link" href="#index-gnutls_005fprotocol_005flist"> &para;</a></span></dt>
<dd>
<p>Get a list of supported protocols, e.g. SSL 3.0, TLS 1.0 etc.
</p>
<p>This function is not thread safe.
</p>
<p><strong class="strong">Returns:</strong> a (0)-terminated list of <code class="code">gnutls_protocol_t</code>  integers
indicating the available protocols.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprotocol_005fset_005fenabled-1"><span>gnutls_protocol_set_enabled<a class="copiable-link" href="#gnutls_005fprotocol_005fset_005fenabled-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprotocol_005fset_005fenabled"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprotocol_005fset_005fenabled"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_protocol_set_enabled</strong> <code class="def-code-arguments">(gnutls_protocol_t <var class="var">version</var>, unsigned int <var class="var">enabled</var>)</code><a class="copiable-link" href="#index-gnutls_005fprotocol_005fset_005fenabled"> &para;</a></span></dt>
<dd><p><var class="var">version</var>: is a (gnutls) version number
</p>
<p><var class="var">enabled</var>: whether to enable the protocol
</p>
<p>Control the previous system-wide setting that marked  <code class="code">version</code> as
enabled or disabled.  Calling this function is allowed
only if allowlisting mode is set in the configuration file,
and only if the system-wide TLS priority string
has not been initialized yet.
The intended usage is to provide applications with a way
to expressly deviate from the distribution or site defaults
inherited from the configuration file.
The modification is composable with further modifications
performed through the priority string mechanism.
</p>
<p>This function is not thread-safe and is intended to be called
in the main thread at the beginning of the process execution.
</p>
<p><strong class="strong">Returns:</strong> 0 on success or negative error code otherwise.
</p>
<p><strong class="strong">Since:</strong> 3.7.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpsk_005fallocate_005fclient_005fcredentials-1"><span>gnutls_psk_allocate_client_credentials<a class="copiable-link" href="#gnutls_005fpsk_005fallocate_005fclient_005fcredentials-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpsk_005fallocate_005fclient_005fcredentials"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpsk_005fallocate_005fclient_005fcredentials"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_psk_allocate_client_credentials</strong> <code class="def-code-arguments">(gnutls_psk_client_credentials_t * <var class="var">sc</var>)</code><a class="copiable-link" href="#index-gnutls_005fpsk_005fallocate_005fclient_005fcredentials"> &para;</a></span></dt>
<dd><p><var class="var">sc</var>: is a pointer to a <code class="code">gnutls_psk_client_credentials_t</code>  type.
</p>
<p>Allocate a gnutls_psk_client_credentials_t structure.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise
an error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpsk_005fallocate_005fclient_005fcredentials2-1"><span>gnutls_psk_allocate_client_credentials2<a class="copiable-link" href="#gnutls_005fpsk_005fallocate_005fclient_005fcredentials2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpsk_005fallocate_005fclient_005fcredentials2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpsk_005fallocate_005fclient_005fcredentials2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_psk_allocate_client_credentials2</strong> <code class="def-code-arguments">(gnutls_psk_client_credentials_t * <var class="var">sc</var>, gnutls_mac_algorithm_t <var class="var">mac</var>)</code><a class="copiable-link" href="#index-gnutls_005fpsk_005fallocate_005fclient_005fcredentials2"> &para;</a></span></dt>
<dd><p><var class="var">sc</var>: is a pointer to a <code class="code">gnutls_psk_client_credentials_t</code>  type.
</p>
<p><var class="var">mac</var>: encryption algorithm to use
</p>
<p>Allocate a gnutls_psk_client_credentials_t structure and initializes
the HMAC binder algorithm to  <code class="code">mac</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise
an error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpsk_005fallocate_005fserver_005fcredentials-1"><span>gnutls_psk_allocate_server_credentials<a class="copiable-link" href="#gnutls_005fpsk_005fallocate_005fserver_005fcredentials-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpsk_005fallocate_005fserver_005fcredentials"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpsk_005fallocate_005fserver_005fcredentials"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_psk_allocate_server_credentials</strong> <code class="def-code-arguments">(gnutls_psk_server_credentials_t * <var class="var">sc</var>)</code><a class="copiable-link" href="#index-gnutls_005fpsk_005fallocate_005fserver_005fcredentials"> &para;</a></span></dt>
<dd><p><var class="var">sc</var>: is a pointer to a <code class="code">gnutls_psk_server_credentials_t</code>  type.
</p>
<p>Allocate a gnutls_psk_server_credentials_t structure.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise
an error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpsk_005fallocate_005fserver_005fcredentials2-1"><span>gnutls_psk_allocate_server_credentials2<a class="copiable-link" href="#gnutls_005fpsk_005fallocate_005fserver_005fcredentials2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpsk_005fallocate_005fserver_005fcredentials2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpsk_005fallocate_005fserver_005fcredentials2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_psk_allocate_server_credentials2</strong> <code class="def-code-arguments">(gnutls_psk_server_credentials_t * <var class="var">sc</var>, gnutls_mac_algorithm_t <var class="var">mac</var>)</code><a class="copiable-link" href="#index-gnutls_005fpsk_005fallocate_005fserver_005fcredentials2"> &para;</a></span></dt>
<dd><p><var class="var">sc</var>: is a pointer to a <code class="code">gnutls_psk_server_credentials_t</code>  type.
</p>
<p><var class="var">mac</var>: encryption algorithm to use
</p>
<p>Allocate a gnutls_psk_server_credentials_t structure and initializes
the HMAC binder algorithm to  <code class="code">mac</code> . If  <code class="code">mac</code> is set to GNUTLS_MAC_UNKNOWN
both possible algorithms SHA384 and SHA256 are applied to find a matching
binder value.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise
an error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpsk_005fclient_005fget_005fhint-1"><span>gnutls_psk_client_get_hint<a class="copiable-link" href="#gnutls_005fpsk_005fclient_005fget_005fhint-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpsk_005fclient_005fget_005fhint"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpsk_005fclient_005fget_005fhint"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_psk_client_get_hint</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fpsk_005fclient_005fget_005fhint"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a gnutls session
</p>
<p>The PSK identity hint may give the client help in deciding which
username to use.  This should only be called in case of PSK
authentication and in case of a client.
</p>
<p><strong class="strong">Note:</strong> there is no hint in TLS 1.3, so this function will return <code class="code">NULL</code> 
if TLS 1.3 has been negotiated.
</p>
<p><strong class="strong">Returns:</strong> the identity hint of the peer, or <code class="code">NULL</code>  in case of an error or if TLS 1.3 is being used.
</p>
<p><strong class="strong">Since:</strong> 2.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpsk_005fformat_005fimported_005fidentity-1"><span>gnutls_psk_format_imported_identity<a class="copiable-link" href="#gnutls_005fpsk_005fformat_005fimported_005fidentity-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpsk_005fformat_005fimported_005fidentity"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpsk_005fformat_005fimported_005fidentity"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_psk_format_imported_identity</strong> <code class="def-code-arguments">(const gnutls_datum_t * <var class="var">identity</var>, const gnutls_datum_t * <var class="var">context</var>, gnutls_protocol_t <var class="var">version</var>, gnutls_digest_algorithm_t <var class="var">hash</var>, gnutls_datum_t * <var class="var">imported_identity</var>)</code><a class="copiable-link" href="#index-gnutls_005fpsk_005fformat_005fimported_005fidentity"> &para;</a></span></dt>
<dd><p><var class="var">identity</var>: external identity
</p>
<p><var class="var">context</var>: optional contextual information
</p>
<p><var class="var">version</var>: protocol version to which the PSK is imported
</p>
<p><var class="var">hash</var>: hash algorithm used for KDF
</p>
<p><var class="var">imported_identity</var>: where the imported identity is stored
</p>
<p>This formats an external PSK identity  <code class="code">identity</code> into an imported
form, described in RFC 9258 as ImportedIdentity.
</p>
<p>Upon success, the data field of  <code class="code">imported_identity</code> is allocated
using <code class="code">gnutls_malloc()</code>  and the caller must free the memory after
use.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  (0) on success, otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.8.1
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpsk_005ffree_005fclient_005fcredentials-1"><span>gnutls_psk_free_client_credentials<a class="copiable-link" href="#gnutls_005fpsk_005ffree_005fclient_005fcredentials-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpsk_005ffree_005fclient_005fcredentials"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpsk_005ffree_005fclient_005fcredentials"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_psk_free_client_credentials</strong> <code class="def-code-arguments">(gnutls_psk_client_credentials_t <var class="var">sc</var>)</code><a class="copiable-link" href="#index-gnutls_005fpsk_005ffree_005fclient_005fcredentials"> &para;</a></span></dt>
<dd><p><var class="var">sc</var>: is a <code class="code">gnutls_psk_client_credentials_t</code>  type.
</p>
<p>Free a gnutls_psk_client_credentials_t structure.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpsk_005ffree_005fserver_005fcredentials-1"><span>gnutls_psk_free_server_credentials<a class="copiable-link" href="#gnutls_005fpsk_005ffree_005fserver_005fcredentials-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpsk_005ffree_005fserver_005fcredentials"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpsk_005ffree_005fserver_005fcredentials"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_psk_free_server_credentials</strong> <code class="def-code-arguments">(gnutls_psk_server_credentials_t <var class="var">sc</var>)</code><a class="copiable-link" href="#index-gnutls_005fpsk_005ffree_005fserver_005fcredentials"> &para;</a></span></dt>
<dd><p><var class="var">sc</var>: is a <code class="code">gnutls_psk_server_credentials_t</code>  type.
</p>
<p>Free a gnutls_psk_server_credentials_t structure.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpsk_005fserver_005fget_005fusername-1"><span>gnutls_psk_server_get_username<a class="copiable-link" href="#gnutls_005fpsk_005fserver_005fget_005fusername-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpsk_005fserver_005fget_005fusername"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpsk_005fserver_005fget_005fusername"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_psk_server_get_username</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fpsk_005fserver_005fget_005fusername"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a gnutls session
</p>
<p>This should only be called in case of PSK authentication and in
case of a server.
</p>
<p>The returned pointer should be considered constant (do not free) and valid 
for the lifetime of the session.
</p>
<p>This function will return <code class="code">NULL</code>  if the username has embedded NULL bytes.
In that case, <code class="code">gnutls_psk_server_get_username2()</code>  should be used to retrieve the username.
</p>
<p><strong class="strong">Returns:</strong> the username of the peer, or <code class="code">NULL</code>  in case of an error,
or if the username has embedded NULLs.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpsk_005fserver_005fget_005fusername2-1"><span>gnutls_psk_server_get_username2<a class="copiable-link" href="#gnutls_005fpsk_005fserver_005fget_005fusername2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpsk_005fserver_005fget_005fusername2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpsk_005fserver_005fget_005fusername2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_psk_server_get_username2</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_datum_t * <var class="var">username</var>)</code><a class="copiable-link" href="#index-gnutls_005fpsk_005fserver_005fget_005fusername2"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a gnutls session
</p>
<p><var class="var">username</var>: a datum that will be filled in by this function
</p>
<p>Return a pointer to the username of the peer in the supplied datum. Does not
need to be null-terminated.
</p>
<p>This should only be called in case of PSK authentication and in
case of a server.
</p>
<p>The returned pointer should be considered constant (do not free) and valid 
for the lifetime of the session.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code> , or a negative value in case of an error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpsk_005fset_005fclient_005fcredentials-1"><span>gnutls_psk_set_client_credentials<a class="copiable-link" href="#gnutls_005fpsk_005fset_005fclient_005fcredentials-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpsk_005fset_005fclient_005fcredentials"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpsk_005fset_005fclient_005fcredentials"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_psk_set_client_credentials</strong> <code class="def-code-arguments">(gnutls_psk_client_credentials_t <var class="var">res</var>, const char * <var class="var">username</var>, const gnutls_datum_t * <var class="var">key</var>, gnutls_psk_key_flags <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpsk_005fset_005fclient_005fcredentials"> &para;</a></span></dt>
<dd><p><var class="var">res</var>: is a <code class="code">gnutls_psk_client_credentials_t</code>  type.
</p>
<p><var class="var">username</var>: is the user&rsquo;s zero-terminated userid
</p>
<p><var class="var">key</var>: is the user&rsquo;s key
</p>
<p><var class="var">flags</var>: indicate the format of the key, either
<code class="code">GNUTLS_PSK_KEY_RAW</code>  or <code class="code">GNUTLS_PSK_KEY_HEX</code> .
</p>
<p>This function sets the username and password, in a
gnutls_psk_client_credentials_t type.  Those will be used in
PSK authentication.   <code class="code">username</code> should be an ASCII string or UTF-8
string. In case of a UTF-8 string it is recommended to be following
the PRECIS framework for usernames (rfc8265). The key can be either
in raw byte format or in Hex format (without the 0x prefix).
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise
an error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpsk_005fset_005fclient_005fcredentials2-1"><span>gnutls_psk_set_client_credentials2<a class="copiable-link" href="#gnutls_005fpsk_005fset_005fclient_005fcredentials2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpsk_005fset_005fclient_005fcredentials2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpsk_005fset_005fclient_005fcredentials2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_psk_set_client_credentials2</strong> <code class="def-code-arguments">(gnutls_psk_client_credentials_t <var class="var">res</var>, const gnutls_datum_t * <var class="var">username</var>, const gnutls_datum_t * <var class="var">key</var>, gnutls_psk_key_flags <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpsk_005fset_005fclient_005fcredentials2"> &para;</a></span></dt>
<dd><p><var class="var">res</var>: is a <code class="code">gnutls_psk_client_credentials_t</code>  type.
</p>
<p><var class="var">username</var>: is the userid
</p>
<p><var class="var">key</var>: is the user&rsquo;s key
</p>
<p><var class="var">flags</var>: indicate the format of the key, either
<code class="code">GNUTLS_PSK_KEY_RAW</code>  or <code class="code">GNUTLS_PSK_KEY_HEX</code> .
</p>
<p>This function is identical to <code class="code">gnutls_psk_set_client_credentials()</code> ,
except that it allows a non-null-terminated username to be introduced.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise
an error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpsk_005fset_005fclient_005fcredentials_005ffunction-1"><span>gnutls_psk_set_client_credentials_function<a class="copiable-link" href="#gnutls_005fpsk_005fset_005fclient_005fcredentials_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpsk_005fset_005fclient_005fcredentials_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpsk_005fset_005fclient_005fcredentials_005ffunction-1"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_psk_set_client_credentials_function</strong> <code class="def-code-arguments">(gnutls_psk_client_credentials_t <var class="var">cred</var>, gnutls_psk_client_credentials_function * <var class="var">func</var>)</code><a class="copiable-link" href="#index-gnutls_005fpsk_005fset_005fclient_005fcredentials_005ffunction-1"> &para;</a></span></dt>
<dd><p><var class="var">cred</var>: is a <code class="code">gnutls_psk_server_credentials_t</code>  type.
</p>
<p><var class="var">func</var>: is the callback function
</p>
<p>This function can be used to set a callback to retrieve the username and
password for client PSK authentication.
The callback&rsquo;s function form is:
int (*callback)(gnutls_session_t, char** username,
gnutls_datum_t* key);
</p>
<p>The  <code class="code">username</code> and  <code class="code">key</code> -&gt;data must be allocated using <code class="code">gnutls_malloc()</code> .
The  <code class="code">username</code> should be an ASCII string or UTF-8
string. In case of a UTF-8 string it is recommended to be following
the PRECIS framework for usernames (rfc8265).
</p>
<p>The callback function will be called once per handshake.
</p>
<p>The callback function should return 0 on success.
-1 indicates an error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpsk_005fset_005fclient_005fcredentials_005ffunction2-1"><span>gnutls_psk_set_client_credentials_function2<a class="copiable-link" href="#gnutls_005fpsk_005fset_005fclient_005fcredentials_005ffunction2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpsk_005fset_005fclient_005fcredentials_005ffunction2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpsk_005fset_005fclient_005fcredentials_005ffunction2"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_psk_set_client_credentials_function2</strong> <code class="def-code-arguments">(gnutls_psk_client_credentials_t <var class="var">cred</var>, gnutls_psk_client_credentials_function2 * <var class="var">func</var>)</code><a class="copiable-link" href="#index-gnutls_005fpsk_005fset_005fclient_005fcredentials_005ffunction2"> &para;</a></span></dt>
<dd><p><var class="var">cred</var>: is a <code class="code">gnutls_psk_server_credentials_t</code>  type.
</p>
<p><var class="var">func</var>: is the callback function
</p>
<p>This function can be used to set a callback to retrieve the username and
password for client PSK authentication.
The callback&rsquo;s function form is:
int (*callback)(gnutls_session_t, gnutls_datum_t* username,
gnutls_datum_t* key);
</p>
<p>This callback function has the same semantics as that of <code class="code">gnutls_psk_set_client_credentials_function()</code> ,
but it allows non-string usernames to be used.
</p>
<p>The  <code class="code">username</code> and  <code class="code">key</code> -&gt;data must be allocated using <code class="code">gnutls_malloc()</code> .
The  <code class="code">username</code> should be an ASCII string or UTF-8
string. In case of a UTF-8 string it is recommended to be following
the PRECIS framework for usernames (rfc8265).
</p>
<p>The callback function will be called once per handshake.
</p>
<p>The callback function should return 0 on success.
-1 indicates an error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpsk_005fset_005fclient_005fcredentials_005ffunction3-1"><span>gnutls_psk_set_client_credentials_function3<a class="copiable-link" href="#gnutls_005fpsk_005fset_005fclient_005fcredentials_005ffunction3-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpsk_005fset_005fclient_005fcredentials_005ffunction3"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpsk_005fset_005fclient_005fcredentials_005ffunction3"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_psk_set_client_credentials_function3</strong> <code class="def-code-arguments">(gnutls_psk_client_credentials_t <var class="var">cred</var>, gnutls_psk_client_credentials_function3 * <var class="var">func</var>)</code><a class="copiable-link" href="#index-gnutls_005fpsk_005fset_005fclient_005fcredentials_005ffunction3"> &para;</a></span></dt>
<dd><p><var class="var">cred</var>: is a <code class="code">gnutls_psk_server_credentials_t</code>  type.
</p>
<p><var class="var">func</var>: is the callback function
</p>
<p>This function can be used to set a callback to retrieve the username and
password for client PSK authentication.
The callback&rsquo;s function form is:
int (*callback)(gnutls_session_t, gnutls_datum_t* username,
gnutls_datum_t* key, gnutls_datum_t* context, gnutls_psk_key_flags *flags);
</p>
<p>This callback function has the same semantics as that of
<code class="code">gnutls_psk_set_client_credentials_function2()</code> , but it returns flags
associated with the key.  The callback may import external PSK
using the method described in RFC 9258 by using
<code class="code">gnutls_psk_format_imported_identity()</code> .
</p>
<p>The data field of  <code class="code">username</code> ,  <code class="code">key</code> , and  <code class="code">context</code> must be allocated
using <code class="code">gnutls_malloc()</code> .  The  <code class="code">username</code> should be an ASCII string or
UTF-8 string. In case of a UTF-8 string it is recommended to be
following the PRECIS framework for usernames (rfc8265).
</p>
<p>The callback function will be called once per handshake.
</p>
<p>The callback function should return 0 on success.
-1 indicates an error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpsk_005fset_005fparams_005ffunction-1"><span>gnutls_psk_set_params_function<a class="copiable-link" href="#gnutls_005fpsk_005fset_005fparams_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpsk_005fset_005fparams_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpsk_005fset_005fparams_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_psk_set_params_function</strong> <code class="def-code-arguments">(gnutls_psk_server_credentials_t <var class="var">res</var>, gnutls_params_function * <var class="var">func</var>)</code><a class="copiable-link" href="#index-gnutls_005fpsk_005fset_005fparams_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">res</var>: is a gnutls_psk_server_credentials_t type
</p>
<p><var class="var">func</var>: is the function to be called
</p>
<p>This function will set a callback in order for the server to get
the Diffie-Hellman or RSA parameters for PSK authentication.  The
callback should return <code class="code">GNUTLS_E_SUCCESS</code>  (0) on success.
</p>
<p><strong class="strong">Deprecated:</strong> This function is unnecessary and discouraged on GnuTLS 3.6.0
or later. Since 3.6.0, DH parameters are negotiated
following RFC7919.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpsk_005fset_005fserver_005fcredentials_005ffile-1"><span>gnutls_psk_set_server_credentials_file<a class="copiable-link" href="#gnutls_005fpsk_005fset_005fserver_005fcredentials_005ffile-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpsk_005fset_005fserver_005fcredentials_005ffile"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpsk_005fset_005fserver_005fcredentials_005ffile-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_psk_set_server_credentials_file</strong> <code class="def-code-arguments">(gnutls_psk_server_credentials_t <var class="var">res</var>, const char * <var class="var">password_file</var>)</code><a class="copiable-link" href="#index-gnutls_005fpsk_005fset_005fserver_005fcredentials_005ffile-1"> &para;</a></span></dt>
<dd><p><var class="var">res</var>: is a <code class="code">gnutls_psk_server_credentials_t</code>  type.
</p>
<p><var class="var">password_file</var>: is the PSK password file (passwd.psk)
</p>
<p>This function sets the password file, in a
<code class="code">gnutls_psk_server_credentials_t</code>  type.  This password file
holds usernames and keys and will be used for PSK authentication.
</p>
<p>Each entry in the file consists of a username, followed by a colon
(&rsquo;:&rsquo;) and a hex-encoded key.  If the username contains a colon or
any other special character, it can be hex-encoded preceded by a
&rsquo;#&rsquo;.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise
an error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpsk_005fset_005fserver_005fcredentials_005ffunction-1"><span>gnutls_psk_set_server_credentials_function<a class="copiable-link" href="#gnutls_005fpsk_005fset_005fserver_005fcredentials_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpsk_005fset_005fserver_005fcredentials_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpsk_005fset_005fserver_005fcredentials_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_psk_set_server_credentials_function</strong> <code class="def-code-arguments">(gnutls_psk_server_credentials_t <var class="var">cred</var>, gnutls_psk_server_credentials_function * <var class="var">func</var>)</code><a class="copiable-link" href="#index-gnutls_005fpsk_005fset_005fserver_005fcredentials_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">cred</var>: is a <code class="code">gnutls_psk_server_credentials_t</code>  type.
</p>
<p><var class="var">func</var>: is the callback function
</p>
<p>This function can be used to set a callback to retrieve the user&rsquo;s PSK credentials.
The callback&rsquo;s function form is:
int (*callback)(gnutls_session_t, const char* username,
gnutls_datum_t* key);
</p>
<p><code class="code">username</code> contains the actual username.
The  <code class="code">key</code> must be filled in using the <code class="code">gnutls_malloc()</code> .
</p>
<p>In case the callback returned a negative number then gnutls will
assume that the username does not exist.
</p>
<p>The callback function will only be called once per handshake.  The
callback function should return 0 on success, while -1 indicates
an error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpsk_005fset_005fserver_005fcredentials_005ffunction2-1"><span>gnutls_psk_set_server_credentials_function2<a class="copiable-link" href="#gnutls_005fpsk_005fset_005fserver_005fcredentials_005ffunction2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpsk_005fset_005fserver_005fcredentials_005ffunction2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpsk_005fset_005fserver_005fcredentials_005ffunction2"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_psk_set_server_credentials_function2</strong> <code class="def-code-arguments">(gnutls_psk_server_credentials_t <var class="var">cred</var>, gnutls_psk_server_credentials_function2 <var class="var">func</var>)</code><a class="copiable-link" href="#index-gnutls_005fpsk_005fset_005fserver_005fcredentials_005ffunction2"> &para;</a></span></dt>
<dd><p><var class="var">cred</var>: is a <code class="code">gnutls_psk_server_credentials_t</code>  type.
</p>
<p><var class="var">func</var>: is the callback function
</p>
<p>This function can be used to set a callback to retrieve the user&rsquo;s PSK credentials.
The callback&rsquo;s function form is:
int (*callback)(gnutls_session_t, const gnutls_datum_t* username,
gnutls_datum_t* key);
</p>
<p>This callback function has the same semantics as that of <code class="code">gnutls_psk_set_server_credentials_function()</code> ,
but it allows non-string usernames to be used.
</p>
<p><code class="code">username</code> contains the actual username.
The  <code class="code">key</code> must be filled in using the <code class="code">gnutls_malloc()</code> .
</p>
<p>In case the callback returned a negative number then gnutls will
assume that the username does not exist.
</p>
<p>The callback function will only be called once per handshake.  The
callback function should return 0 on success, while -1 indicates
an error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpsk_005fset_005fserver_005fcredentials_005ffunction3-1"><span>gnutls_psk_set_server_credentials_function3<a class="copiable-link" href="#gnutls_005fpsk_005fset_005fserver_005fcredentials_005ffunction3-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpsk_005fset_005fserver_005fcredentials_005ffunction3"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpsk_005fset_005fserver_005fcredentials_005ffunction3"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_psk_set_server_credentials_function3</strong> <code class="def-code-arguments">(gnutls_psk_server_credentials_t <var class="var">cred</var>, gnutls_psk_server_credentials_function3 <var class="var">func</var>)</code><a class="copiable-link" href="#index-gnutls_005fpsk_005fset_005fserver_005fcredentials_005ffunction3"> &para;</a></span></dt>
<dd><p><var class="var">cred</var>: is a <code class="code">gnutls_psk_server_credentials_t</code>  type.
</p>
<p><var class="var">func</var>: is the callback function
</p>
<p>This function can be used to set a callback to retrieve the user&rsquo;s PSK credentials.
The callback&rsquo;s function form is:
int (*callback)(gnutls_session_t, const gnutls_datum_t* username,
gnutls_datum_t* key, gnutls_psk_key_flags *flags);
</p>
<p>This callback function has the same semantics as that of
<code class="code">gnutls_psk_set_server_credentials_function2()</code> , but it returns flags
associated with the key.  The callback may import external PSK
using the method described in RFC 9258 by using
<code class="code">gnutls_psk_format_imported_identity()</code> .
</p>
<p><code class="code">username</code> contains the actual username.
The  <code class="code">key</code> must be filled in using the <code class="code">gnutls_malloc()</code> .
</p>
<p>In case the callback returned a negative number then gnutls will
assume that the username does not exist.
</p>
<p>The callback function will only be called once per handshake.  The
callback function should return 0 on success, while -1 indicates
an error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpsk_005fset_005fserver_005fcredentials_005fhint-1"><span>gnutls_psk_set_server_credentials_hint<a class="copiable-link" href="#gnutls_005fpsk_005fset_005fserver_005fcredentials_005fhint-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpsk_005fset_005fserver_005fcredentials_005fhint"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpsk_005fset_005fserver_005fcredentials_005fhint"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_psk_set_server_credentials_hint</strong> <code class="def-code-arguments">(gnutls_psk_server_credentials_t <var class="var">res</var>, const char * <var class="var">hint</var>)</code><a class="copiable-link" href="#index-gnutls_005fpsk_005fset_005fserver_005fcredentials_005fhint"> &para;</a></span></dt>
<dd><p><var class="var">res</var>: is a <code class="code">gnutls_psk_server_credentials_t</code>  type.
</p>
<p><var class="var">hint</var>: is the PSK identity hint string
</p>
<p>This function sets the identity hint, in a
<code class="code">gnutls_psk_server_credentials_t</code>  type.  This hint is sent to
the client to help it chose a good PSK credential (i.e., username
and password).
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise
an error code is returned.
</p>
<p><strong class="strong">Since:</strong> 2.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpsk_005fset_005fserver_005fdh_005fparams-1"><span>gnutls_psk_set_server_dh_params<a class="copiable-link" href="#gnutls_005fpsk_005fset_005fserver_005fdh_005fparams-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpsk_005fset_005fserver_005fdh_005fparams"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpsk_005fset_005fserver_005fdh_005fparams"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_psk_set_server_dh_params</strong> <code class="def-code-arguments">(gnutls_psk_server_credentials_t <var class="var">res</var>, gnutls_dh_params_t <var class="var">dh_params</var>)</code><a class="copiable-link" href="#index-gnutls_005fpsk_005fset_005fserver_005fdh_005fparams"> &para;</a></span></dt>
<dd><p><var class="var">res</var>: is a gnutls_psk_server_credentials_t type
</p>
<p><var class="var">dh_params</var>: is a structure that holds Diffie-Hellman parameters.
</p>
<p>This function will set the Diffie-Hellman parameters for an
anonymous server to use. These parameters will be used in
Diffie-Hellman exchange with PSK cipher suites.
</p>
<p><strong class="strong">Deprecated:</strong> This function is unnecessary and discouraged on GnuTLS 3.6.0
or later. Since 3.6.0, DH parameters are negotiated
following RFC7919.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpsk_005fset_005fserver_005fknown_005fdh_005fparams-1"><span>gnutls_psk_set_server_known_dh_params<a class="copiable-link" href="#gnutls_005fpsk_005fset_005fserver_005fknown_005fdh_005fparams-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpsk_005fset_005fserver_005fknown_005fdh_005fparams"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpsk_005fset_005fserver_005fknown_005fdh_005fparams"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_psk_set_server_known_dh_params</strong> <code class="def-code-arguments">(gnutls_psk_server_credentials_t <var class="var">res</var>, gnutls_sec_param_t <var class="var">sec_param</var>)</code><a class="copiable-link" href="#index-gnutls_005fpsk_005fset_005fserver_005fknown_005fdh_005fparams"> &para;</a></span></dt>
<dd><p><var class="var">res</var>: is a gnutls_psk_server_credentials_t type
</p>
<p><var class="var">sec_param</var>: is an option of the <code class="code">gnutls_sec_param_t</code>  enumeration
</p>
<p>This function will set the Diffie-Hellman parameters for a
PSK server to use. These parameters will be used in
Ephemeral Diffie-Hellman cipher suites and will be selected from
the FFDHE set of RFC7919 according to the security level provided.
</p>
<p><strong class="strong">Deprecated:</strong> This function is unnecessary and discouraged on GnuTLS 3.6.0
or later. Since 3.6.0, DH parameters are negotiated
following RFC7919.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.5.6
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpsk_005fset_005fserver_005fparams_005ffunction-1"><span>gnutls_psk_set_server_params_function<a class="copiable-link" href="#gnutls_005fpsk_005fset_005fserver_005fparams_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpsk_005fset_005fserver_005fparams_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpsk_005fset_005fserver_005fparams_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_psk_set_server_params_function</strong> <code class="def-code-arguments">(gnutls_psk_server_credentials_t <var class="var">res</var>, gnutls_params_function * <var class="var">func</var>)</code><a class="copiable-link" href="#index-gnutls_005fpsk_005fset_005fserver_005fparams_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">res</var>: is a <code class="code">gnutls_certificate_credentials_t</code>  type
</p>
<p><var class="var">func</var>: is the function to be called
</p>
<p>This function will set a callback in order for the server to get
the Diffie-Hellman parameters for PSK authentication.  The callback
should return <code class="code">GNUTLS_E_SUCCESS</code>  (0) on success.
</p>
<p><strong class="strong">Deprecated:</strong> This function is unnecessary and discouraged on GnuTLS 3.6.0
or later. Since 3.6.0, DH parameters are negotiated
following RFC7919.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005frandom_005fart-1"><span>gnutls_random_art<a class="copiable-link" href="#gnutls_005frandom_005fart-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005frandom_005fart"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frandom_005fart"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_random_art</strong> <code class="def-code-arguments">(gnutls_random_art_t <var class="var">type</var>, const char * <var class="var">key_type</var>, unsigned int <var class="var">key_size</var>, void * <var class="var">fpr</var>, size_t <var class="var">fpr_size</var>, gnutls_datum_t * <var class="var">art</var>)</code><a class="copiable-link" href="#index-gnutls_005frandom_005fart"> &para;</a></span></dt>
<dd><p><var class="var">type</var>: The type of the random art (for now only <code class="code">GNUTLS_RANDOM_ART_OPENSSH</code>  is supported)
</p>
<p><var class="var">key_type</var>: The type of the key (RSA, DSA etc.)
</p>
<p><var class="var">key_size</var>: The size of the key in bits
</p>
<p><var class="var">fpr</var>: The fingerprint of the key
</p>
<p><var class="var">fpr_size</var>: The size of the fingerprint
</p>
<p><var class="var">art</var>: The returned random art
</p>
<p>This function will convert a given fingerprint to an &quot;artistic&quot;
image. The returned image is allocated using <code class="code">gnutls_malloc()</code> , is
null-terminated but art-&gt;size will not account the terminating null.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise
an error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005frange_005fsplit-1"><span>gnutls_range_split<a class="copiable-link" href="#gnutls_005frange_005fsplit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005frange_005fsplit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frange_005fsplit"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_range_split</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, const gnutls_range_st * <var class="var">orig</var>, gnutls_range_st * <var class="var">next</var>, gnutls_range_st * <var class="var">remainder</var>)</code><a class="copiable-link" href="#index-gnutls_005frange_005fsplit"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type
</p>
<p><var class="var">orig</var>: is the original range provided by the user
</p>
<p><var class="var">next</var>: is the returned range that can be conveyed in a TLS record
</p>
<p><var class="var">remainder</var>: is the returned remaining range
</p>
<p>This function should be used when it is required to hide the length
of very long data that cannot be directly provided to <code class="code">gnutls_record_send_range()</code> .
In that case this function should be called with the desired length
hiding range in  <code class="code">orig</code> . The returned  <code class="code">next</code> value should then be used in
the next call to <code class="code">gnutls_record_send_range()</code>  with the partial data.
That process should be repeated until  <code class="code">remainder</code> is (0,0).
</p>
<p><strong class="strong">Returns:</strong> 0 in case splitting succeeds, non zero in case of error.
Note that  <code class="code">orig</code> is not changed, while the values of  <code class="code">next</code> and  <code class="code">remainder</code> are modified to store the resulting values.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005freauth-1"><span>gnutls_reauth<a class="copiable-link" href="#gnutls_005freauth-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005freauth"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005freauth"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_reauth</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005freauth"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">flags</var>: must be zero
</p>
<p>This function performs the post-handshake authentication
for TLS 1.3. The post-handshake authentication is initiated by the server
by calling this function. Clients respond when <code class="code">GNUTLS_E_REAUTH_REQUEST</code> 
has been seen while receiving data.
</p>
<p>The non-fatal errors expected by this function are:
<code class="code">GNUTLS_E_INTERRUPTED</code> , <code class="code">GNUTLS_E_AGAIN</code> , as well as
<code class="code">GNUTLS_E_GOT_APPLICATION_DATA</code>  when called on server side.
</p>
<p>The former two interrupt the authentication procedure due to the transport
layer being interrupted, and the latter because there were pending data prior
to peer initiating the re-authentication. The server should read/process that
data as unauthenticated and retry calling <code class="code">gnutls_reauth()</code> .
</p>
<p>When this function is called under TLS1.2 or earlier or the peer didn&rsquo;t
advertise post-handshake auth, it always fails with
<code class="code">GNUTLS_E_INVALID_REQUEST</code> . The verification of the received peers certificate
is delegated to the session or credentials verification callbacks. A
server can check whether post handshake authentication is supported
by the client by checking the session flags with <code class="code">gnutls_session_get_flags()</code> .
</p>
<p>Prior to calling this function in server side, the function
<code class="code">gnutls_certificate_server_set_request()</code>  must be called setting expectations
for the received certificate (request or require). If none are set
this function will return with <code class="code">GNUTLS_E_INVALID_REQUEST</code> .
</p>
<p>Note that post handshake authentication is available irrespective
of the initial negotiation type (PSK or certificate). In all cases
however, certificate credentials must be set to the session prior
to calling this function.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on a successful authentication, otherwise a negative error code.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005frecord_005fcan_005fuse_005flength_005fhiding-1"><span>gnutls_record_can_use_length_hiding<a class="copiable-link" href="#gnutls_005frecord_005fcan_005fuse_005flength_005fhiding-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005frecord_005fcan_005fuse_005flength_005fhiding"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frecord_005fcan_005fuse_005flength_005fhiding"><span class="category-def">Function: </span><span><code class="def-type">unsigned</code> <strong class="def-name">gnutls_record_can_use_length_hiding</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005frecord_005fcan_005fuse_005flength_005fhiding"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>If the session supports length-hiding padding, you can
invoke <code class="code">gnutls_record_send_range()</code>  to send a message whose
length is hidden in the given range. If the session does not
support length hiding padding, you can use the standard
<code class="code">gnutls_record_send()</code>  function, or <code class="code">gnutls_record_send_range()</code> 
making sure that the range is the same as the length of the
message you are trying to send.
</p>
<p><strong class="strong">Returns:</strong> true (1) if the current session supports length-hiding
padding, false (0) if the current session does not.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005frecord_005fcheck_005fcorked-1"><span>gnutls_record_check_corked<a class="copiable-link" href="#gnutls_005frecord_005fcheck_005fcorked-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005frecord_005fcheck_005fcorked"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frecord_005fcheck_005fcorked"><span class="category-def">Function: </span><span><code class="def-type">size_t</code> <strong class="def-name">gnutls_record_check_corked</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005frecord_005fcheck_005fcorked"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>This function checks if there pending corked
data in the gnutls buffers &ndash;see <code class="code">gnutls_record_cork()</code> .
</p>
<p><strong class="strong">Returns:</strong> Returns the size of the corked data or zero.
</p>
<p><strong class="strong">Since:</strong> 3.2.8
</p></dd></dl>

<h4 class="subheading" id="gnutls_005frecord_005fcheck_005fpending-1"><span>gnutls_record_check_pending<a class="copiable-link" href="#gnutls_005frecord_005fcheck_005fpending-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005frecord_005fcheck_005fpending"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frecord_005fcheck_005fpending-1"><span class="category-def">Function: </span><span><code class="def-type">size_t</code> <strong class="def-name">gnutls_record_check_pending</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005frecord_005fcheck_005fpending-1"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>This function checks if there are unread data
in the gnutls buffers. If the return value is
non-zero the next call to <code class="code">gnutls_record_recv()</code> 
is guaranteed not to block.
</p>
<p><strong class="strong">Returns:</strong> Returns the size of the data or zero.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005frecord_005fcork-1"><span>gnutls_record_cork<a class="copiable-link" href="#gnutls_005frecord_005fcork-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005frecord_005fcork"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frecord_005fcork-1"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_record_cork</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005frecord_005fcork-1"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>If called, <code class="code">gnutls_record_send()</code>  will no longer send any records.
Any sent records will be cached until <code class="code">gnutls_record_uncork()</code>  is called.
</p>
<p>This function is safe to use with DTLS after GnuTLS 3.3.0.
</p>
<p><strong class="strong">Since:</strong> 3.1.9
</p></dd></dl>

<h4 class="subheading" id="gnutls_005frecord_005fdisable_005fpadding-1"><span>gnutls_record_disable_padding<a class="copiable-link" href="#gnutls_005frecord_005fdisable_005fpadding-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005frecord_005fdisable_005fpadding"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frecord_005fdisable_005fpadding"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_record_disable_padding</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005frecord_005fdisable_005fpadding"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>Used to disabled padding in TLS 1.0 and above.  Normally you do not
need to use this function, but there are buggy clients that
complain if a server pads the encrypted data.  This of course will
disable protection against statistical attacks on the data.
</p>
<p>This function is defunct since 3.1.7. Random padding is disabled
by default unless requested using <code class="code">gnutls_record_send_range()</code> .
</p></dd></dl>

<h4 class="subheading" id="gnutls_005frecord_005fdiscard_005fqueued-1"><span>gnutls_record_discard_queued<a class="copiable-link" href="#gnutls_005frecord_005fdiscard_005fqueued-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005frecord_005fdiscard_005fqueued"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frecord_005fdiscard_005fqueued"><span class="category-def">Function: </span><span><code class="def-type">size_t</code> <strong class="def-name">gnutls_record_discard_queued</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005frecord_005fdiscard_005fqueued"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>This function discards all queued to be sent packets in a DTLS session.
These are the packets queued after an interrupted <code class="code">gnutls_record_send()</code> .
</p>
<p>This function can only be used with transports where <code class="code">send()</code>  is
an all-or-nothing operation (e.g., UDP). When partial writes are allowed
this function will cause session errors.
</p>
<p><strong class="strong">Returns:</strong> The number of bytes discarded.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005frecord_005fget_005fdirection-1"><span>gnutls_record_get_direction<a class="copiable-link" href="#gnutls_005frecord_005fget_005fdirection-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005frecord_005fget_005fdirection"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frecord_005fget_005fdirection-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_record_get_direction</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005frecord_005fget_005fdirection-1"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>This function is useful to determine whether a GnuTLS function was interrupted
while sending or receiving, so that <code class="code">select()</code>  or <code class="code">poll()</code>  may be called appropriately.
</p>
<p>It provides information about the internals of the record
protocol and is only useful if a prior gnutls function call,
e.g.  <code class="code">gnutls_handshake()</code> , was interrupted and returned
<code class="code">GNUTLS_E_INTERRUPTED</code>  or <code class="code">GNUTLS_E_AGAIN</code> . After such an interrupt
applications may call <code class="code">select()</code>  or <code class="code">poll()</code>  before restoring the
interrupted GnuTLS function.
</p>
<p>This function&rsquo;s output is unreliable if you are using the same
 <code class="code">session</code> in different threads for sending and receiving.
</p>
<p><strong class="strong">Returns:</strong> 0 if interrupted while trying to read data, or 1 while trying to write data.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005frecord_005fget_005fmax_005fearly_005fdata_005fsize-1"><span>gnutls_record_get_max_early_data_size<a class="copiable-link" href="#gnutls_005frecord_005fget_005fmax_005fearly_005fdata_005fsize-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005frecord_005fget_005fmax_005fearly_005fdata_005fsize"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frecord_005fget_005fmax_005fearly_005fdata_005fsize"><span class="category-def">Function: </span><span><code class="def-type">size_t</code> <strong class="def-name">gnutls_record_get_max_early_data_size</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005frecord_005fget_005fmax_005fearly_005fdata_005fsize"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>This function returns the maximum early data size in this connection.
This property can only be set to servers.  The client may be
provided with the maximum allowed size through the &quot;early_data&quot;
extension of the NewSessionTicket handshake message.
</p>
<p><strong class="strong">Returns:</strong> The maximum early data size in this connection.
</p>
<p><strong class="strong">Since:</strong> 3.6.5
</p></dd></dl>

<h4 class="subheading" id="gnutls_005frecord_005fget_005fmax_005fsend_005fsize-1"><span>gnutls_record_get_max_send_size<a class="copiable-link" href="#gnutls_005frecord_005fget_005fmax_005fsend_005fsize-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005frecord_005fget_005fmax_005fsend_005fsize"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frecord_005fget_005fmax_005fsend_005fsize"><span class="category-def">Function: </span><span><code class="def-type">size_t</code> <strong class="def-name">gnutls_record_get_max_send_size</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005frecord_005fget_005fmax_005fsend_005fsize"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>Get the maximum plaintext send size. This maybe negotiated, or user specified.
</p>
<p><strong class="strong">Returns:</strong> The maximum plaintext send size.
</p>
<p><strong class="strong">Since:</strong> 3.8.11
</p></dd></dl>

<h4 class="subheading" id="gnutls_005frecord_005fget_005fmax_005fsize-1"><span>gnutls_record_get_max_size<a class="copiable-link" href="#gnutls_005frecord_005fget_005fmax_005fsize-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005frecord_005fget_005fmax_005fsize"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frecord_005fget_005fmax_005fsize"><span class="category-def">Function: </span><span><code class="def-type">size_t</code> <strong class="def-name">gnutls_record_get_max_size</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005frecord_005fget_005fmax_005fsize"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>Get the record size.  The maximum record size is negotiated by the
client after the first handshake message.
</p>
<p><strong class="strong">Returns:</strong> The maximum record packet size in this connection.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005frecord_005fget_005fstate-1"><span>gnutls_record_get_state<a class="copiable-link" href="#gnutls_005frecord_005fget_005fstate-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005frecord_005fget_005fstate"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frecord_005fget_005fstate"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_record_get_state</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, unsigned <var class="var">read</var>, gnutls_datum_t * <var class="var">mac_key</var>, gnutls_datum_t * <var class="var">IV</var>, gnutls_datum_t * <var class="var">cipher_key</var>, unsigned char [8] <var class="var">seq_number</var>)</code><a class="copiable-link" href="#index-gnutls_005frecord_005fget_005fstate"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type
</p>
<p><var class="var">read</var>: if non-zero the read parameters are returned, otherwise the write
</p>
<p><var class="var">mac_key</var>: the key used for MAC (if a MAC is used)
</p>
<p><var class="var">IV</var>: the initialization vector or nonce used
</p>
<p><var class="var">cipher_key</var>: the cipher key
</p>
<p><var class="var">seq_number</var>: A 64-bit sequence number
</p>
<p>This function will return the parameters of the current record state.
These are only useful to be provided to an external off-loading device
or subsystem. The returned values should be considered constant
and valid for the lifetime of the session.
</p>
<p>In that case, to sync the state back you must call <code class="code">gnutls_record_set_state()</code> .
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, or an error code.
</p>
<p>Since 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005frecord_005foverhead_005fsize-1"><span>gnutls_record_overhead_size<a class="copiable-link" href="#gnutls_005frecord_005foverhead_005fsize-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005frecord_005foverhead_005fsize"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frecord_005foverhead_005fsize"><span class="category-def">Function: </span><span><code class="def-type">size_t</code> <strong class="def-name">gnutls_record_overhead_size</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005frecord_005foverhead_005fsize"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is <code class="code">gnutls_session_t</code> 
</p>
<p>This function will return the size in bytes of the overhead
due to TLS (or DTLS) per record. On certain occasions
(e.g., CBC ciphers) the returned value is the maximum
possible overhead.
</p>
<p><strong class="strong">Since:</strong> 3.2.2
</p></dd></dl>

<h4 class="subheading" id="gnutls_005frecord_005frecv-1"><span>gnutls_record_recv<a class="copiable-link" href="#gnutls_005frecord_005frecv-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005frecord_005frecv"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frecord_005frecv-1"><span class="category-def">Function: </span><span><code class="def-type">ssize_t</code> <strong class="def-name">gnutls_record_recv</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, void * <var class="var">data</var>, size_t <var class="var">data_size</var>)</code><a class="copiable-link" href="#index-gnutls_005frecord_005frecv-1"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">data</var>: the buffer that the data will be read into
</p>
<p><var class="var">data_size</var>: the number of requested bytes
</p>
<p>This function has the similar semantics with <code class="code">recv()</code> .  The only
difference is that it accepts a GnuTLS session, and uses different
error codes.
In the special case that the peer requests a renegotiation, the
caller will receive an error code of <code class="code">GNUTLS_E_REHANDSHAKE</code> .  In case
of a client, this message may be simply ignored, replied with an alert
<code class="code">GNUTLS_A_NO_RENEGOTIATION</code> , or replied with a new handshake,
depending on the client&rsquo;s will. A server receiving this error code
can only initiate a new handshake or terminate the session.
</p>
<p>If <code class="code">EINTR</code>  is returned by the internal pull function (the default
is <code class="code">recv()</code> ) then <code class="code">GNUTLS_E_INTERRUPTED</code>  will be returned.  If
<code class="code">GNUTLS_E_INTERRUPTED</code>  or <code class="code">GNUTLS_E_AGAIN</code>  is returned, you must
call this function again to get the data.  See also
<code class="code">gnutls_record_get_direction()</code> .
</p>
<p><strong class="strong">Returns:</strong> The number of bytes received and zero on EOF (for stream
connections).  A negative error code is returned in case of an error.
The number of bytes received might be less than the requested  <code class="code">data_size</code> .
</p></dd></dl>

<h4 class="subheading" id="gnutls_005frecord_005frecv_005fearly_005fdata-1"><span>gnutls_record_recv_early_data<a class="copiable-link" href="#gnutls_005frecord_005frecv_005fearly_005fdata-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005frecord_005frecv_005fearly_005fdata"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frecord_005frecv_005fearly_005fdata"><span class="category-def">Function: </span><span><code class="def-type">ssize_t</code> <strong class="def-name">gnutls_record_recv_early_data</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, void * <var class="var">data</var>, size_t <var class="var">data_size</var>)</code><a class="copiable-link" href="#index-gnutls_005frecord_005frecv_005fearly_005fdata"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">data</var>: the buffer that the data will be read into
</p>
<p><var class="var">data_size</var>: the number of requested bytes
</p>
<p>This function can be used by a server to retrieve data sent early
in the handshake processes when resuming a session.  This is used
to implement a zero-roundtrip (0-RTT) mode.  It has the same
semantics as <code class="code">gnutls_record_recv()</code> .
</p>
<p>This function can be called either in a handshake hook, or after
the handshake is complete.
</p>
<p><strong class="strong">Returns:</strong> The number of bytes received and zero when early data
reading is complete.  A negative error code is returned in case of
an error.  If no early data is received during the handshake, this
function returns <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> .  The
number of bytes received might be less than the requested
 <code class="code">data_size</code> .
</p>
<p><strong class="strong">Since:</strong> 3.6.5
</p></dd></dl>

<h4 class="subheading" id="gnutls_005frecord_005frecv_005fpacket-1"><span>gnutls_record_recv_packet<a class="copiable-link" href="#gnutls_005frecord_005frecv_005fpacket-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005frecord_005frecv_005fpacket"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frecord_005frecv_005fpacket"><span class="category-def">Function: </span><span><code class="def-type">ssize_t</code> <strong class="def-name">gnutls_record_recv_packet</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_packet_t * <var class="var">packet</var>)</code><a class="copiable-link" href="#index-gnutls_005frecord_005frecv_005fpacket"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">packet</var>: the structure that will hold the packet data
</p>
<p>This is a lower-level function than <code class="code">gnutls_record_recv()</code>  and allows
to directly receive the whole decrypted packet. That avoids a
memory copy, and is intended to be used by applications seeking high
performance.
</p>
<p>The received packet is accessed using <code class="code">gnutls_packet_get()</code>  and
must be deinitialized using <code class="code">gnutls_packet_deinit()</code> . The returned
packet will be <code class="code">NULL</code>  if the return value is zero (EOF).
</p>
<p><strong class="strong">Returns:</strong> The number of bytes received and zero on EOF (for stream
connections).  A negative error code is returned in case of an error.
</p>
<p><strong class="strong">Since:</strong> 3.3.5
</p></dd></dl>

<h4 class="subheading" id="gnutls_005frecord_005frecv_005fseq-1"><span>gnutls_record_recv_seq<a class="copiable-link" href="#gnutls_005frecord_005frecv_005fseq-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005frecord_005frecv_005fseq"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frecord_005frecv_005fseq-1"><span class="category-def">Function: </span><span><code class="def-type">ssize_t</code> <strong class="def-name">gnutls_record_recv_seq</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, void * <var class="var">data</var>, size_t <var class="var">data_size</var>, unsigned char * <var class="var">seq</var>)</code><a class="copiable-link" href="#index-gnutls_005frecord_005frecv_005fseq-1"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">data</var>: the buffer that the data will be read into
</p>
<p><var class="var">data_size</var>: the number of requested bytes
</p>
<p><var class="var">seq</var>: is the packet&rsquo;s 64-bit sequence number. Should have space for 8 bytes.
</p>
<p>This function is the same as <code class="code">gnutls_record_recv()</code> , except that
it returns in addition to data, the sequence number of the data.
This is useful in DTLS where record packets might be received
out-of-order. The returned 8-byte sequence number is an
integer in big-endian format and should be
treated as a unique message identification.
</p>
<p><strong class="strong">Returns:</strong> The number of bytes received and zero on EOF.  A negative
error code is returned in case of an error.  The number of bytes
received might be less than  <code class="code">data_size</code> .
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005frecord_005fsend-1"><span>gnutls_record_send<a class="copiable-link" href="#gnutls_005frecord_005fsend-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005frecord_005fsend"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frecord_005fsend-1"><span class="category-def">Function: </span><span><code class="def-type">ssize_t</code> <strong class="def-name">gnutls_record_send</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, const void * <var class="var">data</var>, size_t <var class="var">data_size</var>)</code><a class="copiable-link" href="#index-gnutls_005frecord_005fsend-1"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">data</var>: contains the data to send
</p>
<p><var class="var">data_size</var>: is the length of the data
</p>
<p>This function has the similar semantics with <code class="code">send()</code> .  The only
difference is that it accepts a GnuTLS session, and uses different
error codes.
Note that if the send buffer is full, <code class="code">send()</code>  will block this
function.  See the <code class="code">send()</code>  documentation for more information.
</p>
<p>You can replace the default push function which is <code class="code">send()</code> , by using
<code class="code">gnutls_transport_set_push_function()</code> .
</p>
<p>If the EINTR is returned by the internal push function
then <code class="code">GNUTLS_E_INTERRUPTED</code>  will be returned. If
<code class="code">GNUTLS_E_INTERRUPTED</code>  or <code class="code">GNUTLS_E_AGAIN</code>  is returned, you must
call this function again with the exact same parameters, or provide a
<code class="code">NULL</code>  pointer for  <code class="code">data</code> and 0 for  <code class="code">data_size</code> , in order to write the
same data as before. If you wish to discard the previous data instead
of retrying, you must call <code class="code">gnutls_record_discard_queued()</code>  before
calling this function with different parameters. Note that the latter
works only on special transports (e.g., UDP).
cf. <code class="code">gnutls_record_get_direction()</code> .
</p>
<p>Note that in DTLS this function will return the <code class="code">GNUTLS_E_LARGE_PACKET</code> 
error code if the send data exceed the data MTU value - as returned
by <code class="code">gnutls_dtls_get_data_mtu()</code> . The errno value EMSGSIZE
also maps to <code class="code">GNUTLS_E_LARGE_PACKET</code> .
Note that since 3.2.13 this function can be called under cork in DTLS
mode, and will refuse to send data over the MTU size by returning
<code class="code">GNUTLS_E_LARGE_PACKET</code> .
</p>
<p><strong class="strong">Returns:</strong> The number of bytes sent, or a negative error code.  The
number of bytes sent might be less than  <code class="code">data_size</code> .  The maximum
number of bytes this function can send in a single call depends
on the negotiated maximum record size.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005frecord_005fsend2-1"><span>gnutls_record_send2<a class="copiable-link" href="#gnutls_005frecord_005fsend2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005frecord_005fsend2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frecord_005fsend2-1"><span class="category-def">Function: </span><span><code class="def-type">ssize_t</code> <strong class="def-name">gnutls_record_send2</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, const void * <var class="var">data</var>, size_t <var class="var">data_size</var>, size_t <var class="var">pad</var>, unsigned <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005frecord_005fsend2-1"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">data</var>: contains the data to send
</p>
<p><var class="var">data_size</var>: is the length of the data
</p>
<p><var class="var">pad</var>: padding to be added to the record
</p>
<p><var class="var">flags</var>: must be zero
</p>
<p>This function is identical to <code class="code">gnutls_record_send()</code>  except that it
takes an extra argument to specify padding to be added the record.
To determine the maximum size of padding, use
<code class="code">gnutls_record_get_max_size()</code>  and <code class="code">gnutls_record_overhead_size()</code> .
</p>
<p>Note that in order for GnuTLS to provide constant time processing
of padding and data in TLS1.3, the flag <code class="code">GNUTLS_SAFE_PADDING_CHECK</code> 
must be used in <code class="code">gnutls_init()</code> .
</p>
<p><strong class="strong">Returns:</strong> The number of bytes sent, or a negative error code.  The
number of bytes sent might be less than  <code class="code">data_size</code> .  The maximum
number of bytes this function can send in a single call depends
on the negotiated maximum record size.
</p>
<p><strong class="strong">Since:</strong> 3.6.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005frecord_005fsend_005fearly_005fdata-1"><span>gnutls_record_send_early_data<a class="copiable-link" href="#gnutls_005frecord_005fsend_005fearly_005fdata-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005frecord_005fsend_005fearly_005fdata"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frecord_005fsend_005fearly_005fdata"><span class="category-def">Function: </span><span><code class="def-type">ssize_t</code> <strong class="def-name">gnutls_record_send_early_data</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, const void * <var class="var">data</var>, size_t <var class="var">data_size</var>)</code><a class="copiable-link" href="#index-gnutls_005frecord_005fsend_005fearly_005fdata"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">data</var>: contains the data to send
</p>
<p><var class="var">data_size</var>: is the length of the data
</p>
<p>This function can be used by a client to send data early in the
handshake processes when resuming a session.  This is used to
implement a zero-roundtrip (0-RTT) mode.  It has the same semantics
as <code class="code">gnutls_record_send()</code> .
</p>
<p>There may be a limit to the amount of data sent as early data.  Use
<code class="code">gnutls_record_get_max_early_data_size()</code>  to check the limit.  If the
limit exceeds, this function returns
<code class="code">GNUTLS_E_RECORD_LIMIT_REACHED</code> .
</p>
<p><strong class="strong">Returns:</strong> The number of bytes sent, or a negative error code.  The
number of bytes sent might be less than  <code class="code">data_size</code> .  The maximum
number of bytes this function can send in a single call depends
on the negotiated maximum record size.
</p>
<p><strong class="strong">Since:</strong> 3.6.5
</p></dd></dl>

<h4 class="subheading" id="gnutls_005frecord_005fsend_005ffile-1"><span>gnutls_record_send_file<a class="copiable-link" href="#gnutls_005frecord_005fsend_005ffile-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005frecord_005fsend_005ffile"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frecord_005fsend_005ffile"><span class="category-def">Function: </span><span><code class="def-type">ssize_t</code> <strong class="def-name">gnutls_record_send_file</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, int <var class="var">fd</var>, off_t * <var class="var">offset</var>, size_t <var class="var">count</var>)</code><a class="copiable-link" href="#index-gnutls_005frecord_005fsend_005ffile"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">fd</var>: file descriptor from which to read data.
</p>
<p><var class="var">offset</var>: Is relative to file offset, denotes the starting location for
reading.  after function returns, it point to position following
last read byte.
</p>
<p><var class="var">count</var>: is the length of the data in bytes to be read from file and send.
</p>
<p>This function sends data from  <code class="code">fd</code> . If KTLS (kernel TLS) is enabled, it will
use the <code class="code">sendfile()</code>  system call to avoid overhead of copying data between user
space and the kernel. Otherwise, this functionality is merely emulated by
calling <code class="code">read()</code>  and <code class="code">gnutls_record_send()</code> . If this implementation is
suboptimal, check whether KTLS is enabled using
<code class="code">gnutls_transport_is_ktls_enabled()</code> .
</p>
<p>If  <code class="code">offset</code> is NULL then file offset is incremented by number of bytes send,
otherwise file offset remains unchanged.
</p>
<p><strong class="strong">Returns:</strong> The number of bytes sent, or a negative error code.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005frecord_005fsend_005frange-1"><span>gnutls_record_send_range<a class="copiable-link" href="#gnutls_005frecord_005fsend_005frange-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005frecord_005fsend_005frange"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frecord_005fsend_005frange"><span class="category-def">Function: </span><span><code class="def-type">ssize_t</code> <strong class="def-name">gnutls_record_send_range</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, const void * <var class="var">data</var>, size_t <var class="var">data_size</var>, const gnutls_range_st * <var class="var">range</var>)</code><a class="copiable-link" href="#index-gnutls_005frecord_005fsend_005frange"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">data</var>: contains the data to send.
</p>
<p><var class="var">data_size</var>: is the length of the data.
</p>
<p><var class="var">range</var>: is the range of lengths in which the real data length must be hidden.
</p>
<p>This function operates like <code class="code">gnutls_record_send()</code>  but, while
<code class="code">gnutls_record_send()</code>  adds minimal padding to each TLS record,
this function uses the TLS extra-padding feature to conceal the real
data size within the range of lengths provided.
Some TLS sessions do not support extra padding (e.g. stream ciphers in standard
TLS or SSL3 sessions). To know whether the current session supports extra
padding, and hence length hiding, use the <code class="code">gnutls_record_can_use_length_hiding()</code> 
function.
</p>
<p><strong class="strong">Note:</strong> This function currently is limited to blocking sockets.
</p>
<p><strong class="strong">Returns:</strong> The number of bytes sent (that is data_size in a successful invocation),
or a negative error code.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005frecord_005fset_005fmax_005fearly_005fdata_005fsize-1"><span>gnutls_record_set_max_early_data_size<a class="copiable-link" href="#gnutls_005frecord_005fset_005fmax_005fearly_005fdata_005fsize-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005frecord_005fset_005fmax_005fearly_005fdata_005fsize"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frecord_005fset_005fmax_005fearly_005fdata_005fsize"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_record_set_max_early_data_size</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, size_t <var class="var">size</var>)</code><a class="copiable-link" href="#index-gnutls_005frecord_005fset_005fmax_005fearly_005fdata_005fsize"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">size</var>: is the new size
</p>
<p>This function sets the maximum early data size in this connection.
This property can only be set to servers.  The client may be
provided with the maximum allowed size through the &quot;early_data&quot;
extension of the NewSessionTicket handshake message.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned.
</p>
<p><strong class="strong">Since:</strong> 3.6.4
</p></dd></dl>

<h4 class="subheading" id="gnutls_005frecord_005fset_005fmax_005frecv_005fsize-1"><span>gnutls_record_set_max_recv_size<a class="copiable-link" href="#gnutls_005frecord_005fset_005fmax_005frecv_005fsize-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005frecord_005fset_005fmax_005frecv_005fsize"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frecord_005fset_005fmax_005frecv_005fsize"><span class="category-def">Function: </span><span><code class="def-type">ssize_t</code> <strong class="def-name">gnutls_record_set_max_recv_size</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, size_t <var class="var">size</var>)</code><a class="copiable-link" href="#index-gnutls_005frecord_005fset_005fmax_005frecv_005fsize"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">size</var>: is the new size
</p>
<p>This function sets the maximum amount of plaintext received in a
record in this connection.
</p>
<p>The limit is also negotiated through a TLS extension called &rsquo;record
size limit&rsquo;.  Note that while the &rsquo;record size limit&rsquo; extension is
preferred, not all TLS implementations use or even understand the
extension.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned.
</p>
<p><strong class="strong">Since:</strong> 3.6.8
</p></dd></dl>

<h4 class="subheading" id="gnutls_005frecord_005fset_005fmax_005fsize-1"><span>gnutls_record_set_max_size<a class="copiable-link" href="#gnutls_005frecord_005fset_005fmax_005fsize-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005frecord_005fset_005fmax_005fsize"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frecord_005fset_005fmax_005fsize"><span class="category-def">Function: </span><span><code class="def-type">ssize_t</code> <strong class="def-name">gnutls_record_set_max_size</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, size_t <var class="var">size</var>)</code><a class="copiable-link" href="#index-gnutls_005frecord_005fset_005fmax_005fsize"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">size</var>: is the new size
</p>
<p>This function sets the maximum amount of plaintext sent and
received in a record in this connection.
</p>
<p>Prior to 3.6.4, this function was implemented using a TLS extension
called &rsquo;max fragment length&rsquo;, which limits the acceptable values to
512(=2^9), 1024(=2^10), 2048(=2^11) and 4096(=2^12).
</p>
<p>Since 3.6.4, the limit is also negotiated through a new TLS
extension called &rsquo;record size limit&rsquo;, which doesn&rsquo;t have the
limitation, as long as the value ranges between 512 and 16384.
Note that while the &rsquo;record size limit&rsquo; extension is preferred, not
all TLS implementations use or even understand the extension.
</p>
<p><strong class="strong">Deprecated:</strong> if the client can assume that the &rsquo;record size limit&rsquo;
extension is supported by the server, we recommend using
<code class="code">gnutls_record_set_max_recv_size()</code>  instead.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005frecord_005fset_005fstate-1"><span>gnutls_record_set_state<a class="copiable-link" href="#gnutls_005frecord_005fset_005fstate-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005frecord_005fset_005fstate"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frecord_005fset_005fstate"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_record_set_state</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, unsigned <var class="var">read</var>, const unsigned char [8] <var class="var">seq_number</var>)</code><a class="copiable-link" href="#index-gnutls_005frecord_005fset_005fstate"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type
</p>
<p><var class="var">read</var>: if non-zero the read parameters are returned, otherwise the write
</p>
<p><var class="var">seq_number</var>: A 64-bit sequence number
</p>
<p>This function will set the sequence number in the current record state.
This function is useful if sending and receiving are offloaded from
gnutls. That is, if <code class="code">gnutls_record_get_state()</code>  was used.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, or an error code.
</p>
<p>Since 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005frecord_005fset_005ftimeout-1"><span>gnutls_record_set_timeout<a class="copiable-link" href="#gnutls_005frecord_005fset_005ftimeout-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005frecord_005fset_005ftimeout"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frecord_005fset_005ftimeout"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_record_set_timeout</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, unsigned int <var class="var">ms</var>)</code><a class="copiable-link" href="#index-gnutls_005frecord_005fset_005ftimeout"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">ms</var>: is a timeout value in milliseconds
</p>
<p>This function sets the receive timeout for the record layer
to the provided value. Use an  <code class="code">ms</code> value of zero to disable
timeout (the default), or <code class="code">GNUTLS_INDEFINITE_TIMEOUT</code> , to
set an indefinite timeout.
</p>
<p>This function requires to set a pull timeout callback. See
<code class="code">gnutls_transport_set_pull_timeout_function()</code> .
</p>
<p><strong class="strong">Since:</strong> 3.1.7
</p></dd></dl>

<h4 class="subheading" id="gnutls_005frecord_005funcork-1"><span>gnutls_record_uncork<a class="copiable-link" href="#gnutls_005frecord_005funcork-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005frecord_005funcork"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frecord_005funcork-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_record_uncork</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005frecord_005funcork-1"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">flags</var>: Could be zero or <code class="code">GNUTLS_RECORD_WAIT</code> 
</p>
<p>This resets the effect of <code class="code">gnutls_record_cork()</code> , and flushes any pending
data. If the <code class="code">GNUTLS_RECORD_WAIT</code>  flag is specified then this
function will block until the data is sent or a fatal error
occurs (i.e., the function will retry on <code class="code">GNUTLS_E_AGAIN</code>  and
<code class="code">GNUTLS_E_INTERRUPTED</code> ).
</p>
<p>If the flag <code class="code">GNUTLS_RECORD_WAIT</code>  is not specified and the function
is interrupted then the <code class="code">GNUTLS_E_AGAIN</code>  or <code class="code">GNUTLS_E_INTERRUPTED</code> 
errors will be returned. To obtain the data left in the corked
buffer use <code class="code">gnutls_record_check_corked()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success the number of transmitted data is returned, or
otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.1.9
</p></dd></dl>

<h4 class="subheading" id="gnutls_005frehandshake-1"><span>gnutls_rehandshake<a class="copiable-link" href="#gnutls_005frehandshake-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005frehandshake"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frehandshake-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_rehandshake</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005frehandshake-1"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>This function can only be called in server side, and
instructs a TLS 1.2 or earlier client to renegotiate
parameters (perform a handshake), by sending a
hello request message.
</p>
<p>If this function succeeds, the calling application
should call <code class="code">gnutls_record_recv()</code>  until <code class="code">GNUTLS_E_REHANDSHAKE</code> 
is returned to clear any pending data. If the <code class="code">GNUTLS_E_REHANDSHAKE</code> 
error code is not seen, then the handshake request was
not followed by the peer (the TLS protocol does not require
the client to do, and such compliance should be handled
by the application protocol).
</p>
<p>Once the <code class="code">GNUTLS_E_REHANDSHAKE</code>  error code is seen, the
calling application should proceed to calling
<code class="code">gnutls_handshake()</code>  to negotiate the new
parameters.
</p>
<p>If the client does not wish to renegotiate parameters he
may reply with an alert message, and in that case the return code seen
by subsequent <code class="code">gnutls_record_recv()</code>  will be
<code class="code">GNUTLS_E_WARNING_ALERT_RECEIVED</code>  with the specific alert being
<code class="code">GNUTLS_A_NO_RENEGOTIATION</code> .  A client may also choose to ignore
this request.
</p>
<p>Under TLS 1.3 this function is equivalent to <code class="code">gnutls_session_key_update()</code> 
with the <code class="code">GNUTLS_KU_PEER</code>  flag. In that case subsequent calls to
<code class="code">gnutls_record_recv()</code>  will not return <code class="code">GNUTLS_E_REHANDSHAKE</code> , and
calls to <code class="code">gnutls_handshake()</code>  in server side are a no-op.
</p>
<p>This function always fails with <code class="code">GNUTLS_E_INVALID_REQUEST</code>  when
called in client side.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsafe_005frenegotiation_005fstatus-1"><span>gnutls_safe_renegotiation_status<a class="copiable-link" href="#gnutls_005fsafe_005frenegotiation_005fstatus-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsafe_005frenegotiation_005fstatus"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsafe_005frenegotiation_005fstatus-1"><span class="category-def">Function: </span><span><code class="def-type">unsigned</code> <strong class="def-name">gnutls_safe_renegotiation_status</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fsafe_005frenegotiation_005fstatus-1"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>Can be used to check whether safe renegotiation is being used
in the current session.
</p>
<p><strong class="strong">Returns:</strong> 0 when safe renegotiation is not used and non (0) when
safe renegotiation is used.
</p>
<p><strong class="strong">Since:</strong> 2.10.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsec_005fparam_005fget_005fname-1"><span>gnutls_sec_param_get_name<a class="copiable-link" href="#gnutls_005fsec_005fparam_005fget_005fname-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsec_005fparam_005fget_005fname"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsec_005fparam_005fget_005fname"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_sec_param_get_name</strong> <code class="def-code-arguments">(gnutls_sec_param_t <var class="var">param</var>)</code><a class="copiable-link" href="#index-gnutls_005fsec_005fparam_005fget_005fname"> &para;</a></span></dt>
<dd><p><var class="var">param</var>: is a security parameter
</p>
<p>Convert a <code class="code">gnutls_sec_param_t</code>  value to a string.
</p>
<p><strong class="strong">Returns:</strong> a pointer to a string that contains the name of the
specified security level, or <code class="code">NULL</code> .
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsec_005fparam_005fto_005fpk_005fbits-1"><span>gnutls_sec_param_to_pk_bits<a class="copiable-link" href="#gnutls_005fsec_005fparam_005fto_005fpk_005fbits-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsec_005fparam_005fto_005fpk_005fbits"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsec_005fparam_005fto_005fpk_005fbits-1"><span class="category-def">Function: </span><span><code class="def-type">unsigned int</code> <strong class="def-name">gnutls_sec_param_to_pk_bits</strong> <code class="def-code-arguments">(gnutls_pk_algorithm_t <var class="var">algo</var>, gnutls_sec_param_t <var class="var">param</var>)</code><a class="copiable-link" href="#index-gnutls_005fsec_005fparam_005fto_005fpk_005fbits-1"> &para;</a></span></dt>
<dd><p><var class="var">algo</var>: is a public key algorithm
</p>
<p><var class="var">param</var>: is a security parameter
</p>
<p>When generating private and public key pairs a difficult question
is which size of &quot;bits&quot; the modulus will be in RSA and the group size
in DSA. The easy answer is 1024, which is also wrong. This function
will convert a human understandable security parameter to an
appropriate size for the specific algorithm.
</p>
<p><strong class="strong">Returns:</strong> The number of bits, or (0).
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsec_005fparam_005fto_005fsymmetric_005fbits-1"><span>gnutls_sec_param_to_symmetric_bits<a class="copiable-link" href="#gnutls_005fsec_005fparam_005fto_005fsymmetric_005fbits-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsec_005fparam_005fto_005fsymmetric_005fbits"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsec_005fparam_005fto_005fsymmetric_005fbits"><span class="category-def">Function: </span><span><code class="def-type">unsigned int</code> <strong class="def-name">gnutls_sec_param_to_symmetric_bits</strong> <code class="def-code-arguments">(gnutls_sec_param_t <var class="var">param</var>)</code><a class="copiable-link" href="#index-gnutls_005fsec_005fparam_005fto_005fsymmetric_005fbits"> &para;</a></span></dt>
<dd><p><var class="var">param</var>: is a security parameter
</p>
<p>This function will return the number of bits that correspond to
symmetric cipher strength for the given security parameter.
</p>
<p><strong class="strong">Returns:</strong> The number of bits, or (0).
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fserver_005fname_005fget-1"><span>gnutls_server_name_get<a class="copiable-link" href="#gnutls_005fserver_005fname_005fget-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fserver_005fname_005fget"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fserver_005fname_005fget"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_server_name_get</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, void * <var class="var">data</var>, size_t * <var class="var">data_length</var>, unsigned int * <var class="var">type</var>, unsigned int <var class="var">indx</var>)</code><a class="copiable-link" href="#index-gnutls_005fserver_005fname_005fget"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">data</var>: will hold the data
</p>
<p><var class="var">data_length</var>: will hold the data length. Must hold the maximum size of data.
</p>
<p><var class="var">type</var>: will hold the server name indicator type
</p>
<p><var class="var">indx</var>: is the index of the server_name
</p>
<p>This function will allow you to get the name indication (if any), a
client has sent.  The name indication may be any of the enumeration
gnutls_server_name_type_t.
</p>
<p>If  <code class="code">type</code> is GNUTLS_NAME_DNS, then this function is to be used by
servers that support virtual hosting, and the data will be a null
terminated IDNA ACE string (prior to GnuTLS 3.4.0 it was a UTF-8 string).
</p>
<p>If  <code class="code">data</code> has not enough size to hold the server name
GNUTLS_E_SHORT_MEMORY_BUFFER is returned, and  <code class="code">data_length</code> will
hold the required size.
</p>
<p><code class="code">indx</code> is used to retrieve more than one server names (if sent by
the client).  The first server name has an index of 0, the second 1
and so on.  If no name with the given index exists
GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE is returned.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, on UTF-8
decoding error <code class="code">GNUTLS_E_IDNA_ERROR</code>  is returned, otherwise a negative
error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fserver_005fname_005fset-1"><span>gnutls_server_name_set<a class="copiable-link" href="#gnutls_005fserver_005fname_005fset-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fserver_005fname_005fset"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fserver_005fname_005fset"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_server_name_set</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_server_name_type_t <var class="var">type</var>, const void * <var class="var">name</var>, size_t <var class="var">name_length</var>)</code><a class="copiable-link" href="#index-gnutls_005fserver_005fname_005fset"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">type</var>: specifies the indicator type
</p>
<p><var class="var">name</var>: is a string that contains the server name.
</p>
<p><var class="var">name_length</var>: holds the length of name excluding the terminating null byte
</p>
<p>This function is to be used by clients that want to inform (via a
TLS extension mechanism) the server of the name they connected to.
This should be used by clients that connect to servers that do
virtual hosting.
</p>
<p>The value of  <code class="code">name</code> depends on the  <code class="code">type</code> type.  In case of
<code class="code">GNUTLS_NAME_DNS</code> , a UTF-8 null-terminated domain name string,
without the trailing dot, is expected.
</p>
<p>IPv4 or IPv6 addresses are not permitted to be set by this function.
If the function is called with a name of  <code class="code">name_length</code> zero it will clear
all server names set.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsession_005fchannel_005fbinding-1"><span>gnutls_session_channel_binding<a class="copiable-link" href="#gnutls_005fsession_005fchannel_005fbinding-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsession_005fchannel_005fbinding"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsession_005fchannel_005fbinding"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_session_channel_binding</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_channel_binding_t <var class="var">cbtype</var>, gnutls_datum_t * <var class="var">cb</var>)</code><a class="copiable-link" href="#index-gnutls_005fsession_005fchannel_005fbinding"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">cbtype</var>: an <code class="code">gnutls_channel_binding_t</code>  enumeration type
</p>
<p><var class="var">cb</var>: output buffer array with data
</p>
<p>Extract given channel binding data of the  <code class="code">cbtype</code> (e.g.,
<code class="code">GNUTLS_CB_TLS_UNIQUE</code> ) type.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success,
<code class="code">GNUTLS_E_UNIMPLEMENTED_FEATURE</code>  if the  <code class="code">cbtype</code> is unsupported,
<code class="code">GNUTLS_E_CHANNEL_BINDING_NOT_AVAILABLE</code>  if the data is not
currently available, or an error code.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsession_005fenable_005fcompatibility_005fmode-1"><span>gnutls_session_enable_compatibility_mode<a class="copiable-link" href="#gnutls_005fsession_005fenable_005fcompatibility_005fmode-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsession_005fenable_005fcompatibility_005fmode"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsession_005fenable_005fcompatibility_005fmode"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_session_enable_compatibility_mode</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fsession_005fenable_005fcompatibility_005fmode"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>This function can be used to disable certain (security) features in
TLS in order to maintain maximum compatibility with buggy
clients. Because several trade-offs with security are enabled,
if required they will be reported through the audit subsystem.
</p>
<p>Normally only servers that require maximum compatibility with
everything out there, need to call this function.
</p>
<p>Note that this function must be called after any call to gnutls_priority
functions.
</p>
<p><strong class="strong">Since:</strong> 2.1.4
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsession_005fetm_005fstatus-1"><span>gnutls_session_etm_status<a class="copiable-link" href="#gnutls_005fsession_005fetm_005fstatus-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsession_005fetm_005fstatus"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsession_005fetm_005fstatus"><span class="category-def">Function: </span><span><code class="def-type">unsigned</code> <strong class="def-name">gnutls_session_etm_status</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fsession_005fetm_005fstatus"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>Get the status of the encrypt-then-mac extension negotiation.
This is in accordance to rfc7366
</p>
<p><strong class="strong">Returns:</strong> Non-zero if the negotiation was successful or zero otherwise.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsession_005fext_005fmaster_005fsecret_005fstatus-1"><span>gnutls_session_ext_master_secret_status<a class="copiable-link" href="#gnutls_005fsession_005fext_005fmaster_005fsecret_005fstatus-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsession_005fext_005fmaster_005fsecret_005fstatus"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsession_005fext_005fmaster_005fsecret_005fstatus"><span class="category-def">Function: </span><span><code class="def-type">unsigned</code> <strong class="def-name">gnutls_session_ext_master_secret_status</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fsession_005fext_005fmaster_005fsecret_005fstatus"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>Get the status of the extended master secret extension negotiation.
This is in accordance to RFC7627. That information is also
available to the more generic <code class="code">gnutls_session_get_flags()</code> .
</p>
<p><strong class="strong">Returns:</strong> Non-zero if the negotiation was successful or zero otherwise.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsession_005fext_005fregister-1"><span>gnutls_session_ext_register<a class="copiable-link" href="#gnutls_005fsession_005fext_005fregister-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsession_005fext_005fregister"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsession_005fext_005fregister"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_session_ext_register</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, const char * <var class="var">name</var>, int <var class="var">id</var>, gnutls_ext_parse_type_t <var class="var">parse_point</var>, gnutls_ext_recv_func <var class="var">recv_func</var>, gnutls_ext_send_func <var class="var">send_func</var>, gnutls_ext_deinit_data_func <var class="var">deinit_func</var>, gnutls_ext_pack_func <var class="var">pack_func</var>, gnutls_ext_unpack_func <var class="var">unpack_func</var>, unsigned <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fsession_005fext_005fregister"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: the session for which this extension will be set
</p>
<p><var class="var">name</var>: the name of the extension to register
</p>
<p><var class="var">id</var>: the numeric id of the extension
</p>
<p><var class="var">parse_point</var>: the parse type of the extension (see gnutls_ext_parse_type_t)
</p>
<p><var class="var">recv_func</var>: a function to receive the data
</p>
<p><var class="var">send_func</var>: a function to send the data
</p>
<p><var class="var">deinit_func</var>: a function deinitialize any private data
</p>
<p><var class="var">pack_func</var>: a function which serializes the extension&rsquo;s private data (used on session packing for resumption)
</p>
<p><var class="var">unpack_func</var>: a function which will deserialize the extension&rsquo;s private data
</p>
<p><var class="var">flags</var>: must be zero or flags from <code class="code">gnutls_ext_flags_t</code> 
</p>
<p>This function will register a new extension type. The extension will be
only usable within the registered session. If the extension type
is already registered then <code class="code">GNUTLS_E_ALREADY_REGISTERED</code>  will be returned,
unless the flag <code class="code">GNUTLS_EXT_FLAG_OVERRIDE_INTERNAL</code>  is specified. The latter
flag when specified can be used to override certain extensions introduced
after 3.6.0. It is expected to be used by applications which handle
custom extensions that are not currently supported in GnuTLS, but direct
support for them may be added in the future.
</p>
<p>Each registered extension can store temporary data into the gnutls_session_t
structure using <code class="code">gnutls_ext_set_data()</code> , and they can be retrieved using
<code class="code">gnutls_ext_get_data()</code> .
</p>
<p>The validity of the extension registered can be given by the appropriate flags
of <code class="code">gnutls_ext_flags_t</code> . If no validity is given, then the registered extension
will be valid for client and TLS1.2 server hello (or encrypted extensions for TLS1.3).
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.5.5
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsession_005fforce_005fvalid-1"><span>gnutls_session_force_valid<a class="copiable-link" href="#gnutls_005fsession_005fforce_005fvalid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsession_005fforce_005fvalid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsession_005fforce_005fvalid"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_session_force_valid</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fsession_005fforce_005fvalid"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>Clears the invalid flag in a session. That means
that sessions were corrupt or invalid data were received 
can be re-used. Use only when debugging or experimenting
with the TLS protocol. Should not be used in typical
applications.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsession_005fget_005fdata-1"><span>gnutls_session_get_data<a class="copiable-link" href="#gnutls_005fsession_005fget_005fdata-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsession_005fget_005fdata"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsession_005fget_005fdata"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_session_get_data</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, void * <var class="var">session_data</var>, size_t * <var class="var">session_data_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fsession_005fget_005fdata"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">session_data</var>: is a pointer to space to hold the session.
</p>
<p><var class="var">session_data_size</var>: is the session_data&rsquo;s size, or it will be set by the function.
</p>
<p>Returns all session parameters needed to be stored to support resumption,
in a pre-allocated buffer.
</p>
<p>See <code class="code">gnutls_session_get_data2()</code>  for more information.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise
an error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsession_005fget_005fdata2-1"><span>gnutls_session_get_data2<a class="copiable-link" href="#gnutls_005fsession_005fget_005fdata2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsession_005fget_005fdata2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsession_005fget_005fdata2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_session_get_data2</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_datum_t * <var class="var">data</var>)</code><a class="copiable-link" href="#index-gnutls_005fsession_005fget_005fdata2"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">data</var>: is a pointer to a datum that will hold the session.
</p>
<p>Returns necessary parameters to support resumption. The client
should call this function and store the returned session data. A session
can be resumed later by calling <code class="code">gnutls_session_set_data()</code>  with the returned
data. Note that under TLS 1.3, it is recommended for clients to use
session parameters only once, to prevent passive-observers from correlating
the different connections.
</p>
<p>The returned  <code class="code">data</code> are allocated and must be released using <code class="code">gnutls_free()</code> .
</p>
<p>This function will fail if called prior to handshake completion. In
case of false start TLS, the handshake completes only after data have
been successfully received from the peer.
</p>
<p>Under TLS1.3 session resumption is possible only after a session ticket
is received by the client. To ensure that such a ticket has been received use
<code class="code">gnutls_session_get_flags()</code>  and check for flag <code class="code">GNUTLS_SFLAGS_SESSION_TICKET</code> ;
if this flag is not set, this function will wait for a new ticket within
an estimated roundtrip, and if not received will return dummy data which
cannot lead to resumption.
</p>
<p>To get notified when new tickets are received by the server
use <code class="code">gnutls_handshake_set_hook_function()</code>  to wait for <code class="code">GNUTLS_HANDSHAKE_NEW_SESSION_TICKET</code> 
messages. Each call of <code class="code">gnutls_session_get_data2()</code>  after a ticket is
received, will return session resumption data corresponding to the last
received ticket.
</p>
<p>Note that this function under TLS1.3 requires a callback to be set with
<code class="code">gnutls_transport_set_pull_timeout_function()</code>  for successful operation. There
was a bug before 3.6.10 which could make this function fail if that callback
was not set. On later versions if not set, the function will return a successful
error code, but will return dummy data that cannot lead to a resumption.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise
an error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsession_005fget_005fdesc-1"><span>gnutls_session_get_desc<a class="copiable-link" href="#gnutls_005fsession_005fget_005fdesc-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsession_005fget_005fdesc"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsession_005fget_005fdesc"><span class="category-def">Function: </span><span><code class="def-type">char *</code> <strong class="def-name">gnutls_session_get_desc</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fsession_005fget_005fdesc"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a gnutls session
</p>
<p>This function returns a string describing the current session.
The string is null terminated and allocated using <code class="code">gnutls_malloc()</code> .
</p>
<p>If initial negotiation is not complete when this function is called,
<code class="code">NULL</code>  will be returned.
</p>
<p><strong class="strong">Returns:</strong> a description of the protocols and algorithms in the current session.
</p>
<p><strong class="strong">Since:</strong> 3.1.10
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsession_005fget_005fflags-1"><span>gnutls_session_get_flags<a class="copiable-link" href="#gnutls_005fsession_005fget_005fflags-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsession_005fget_005fflags"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsession_005fget_005fflags"><span class="category-def">Function: </span><span><code class="def-type">unsigned</code> <strong class="def-name">gnutls_session_get_flags</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fsession_005fget_005fflags"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>This function will return a series (ORed) of flags, applicable
for the current session.
</p>
<p>This replaces individual informational functions such as
<code class="code">gnutls_safe_renegotiation_status()</code> , <code class="code">gnutls_session_ext_master_secret_status()</code> ,
etc.
</p>
<p><strong class="strong">Returns:</strong> An ORed sequence of flags (see <code class="code">gnutls_session_flags_t</code> )
</p>
<p><strong class="strong">Since:</strong> 3.5.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsession_005fget_005fid-1"><span>gnutls_session_get_id<a class="copiable-link" href="#gnutls_005fsession_005fget_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsession_005fget_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsession_005fget_005fid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_session_get_id</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, void * <var class="var">session_id</var>, size_t * <var class="var">session_id_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fsession_005fget_005fid"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">session_id</var>: is a pointer to space to hold the session id.
</p>
<p><var class="var">session_id_size</var>: initially should contain the maximum  <code class="code">session_id</code> size and will be updated.
</p>
<p>Returns the TLS session identifier. The session ID is selected by the
server, and in older versions of TLS was a unique identifier shared
between client and server which was persistent across resumption.
In the latest version of TLS (1.3) or TLS with session tickets, the
notion of session identifiers is undefined and cannot be relied for uniquely
identifying sessions across client and server.
</p>
<p>In client side this function returns the identifier returned by the
server, and cannot be assumed to have any relation to session resumption.
In server side this function is guaranteed to return a persistent
identifier of the session since GnuTLS 3.6.4, which may not necessarily
map into the TLS session ID value. Prior to that version the value
could only be considered a persistent identifier, under TLS1.2 or earlier
and when no session tickets were in use.
</p>
<p>The session identifier value returned is always less than
<code class="code">GNUTLS_MAX_SESSION_ID_SIZE</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise
an error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsession_005fget_005fid2-1"><span>gnutls_session_get_id2<a class="copiable-link" href="#gnutls_005fsession_005fget_005fid2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsession_005fget_005fid2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsession_005fget_005fid2-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_session_get_id2</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_datum_t * <var class="var">session_id</var>)</code><a class="copiable-link" href="#index-gnutls_005fsession_005fget_005fid2-1"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">session_id</var>: will point to the session ID.
</p>
<p>Returns the TLS session identifier. The session ID is selected by the
server, and in older versions of TLS was a unique identifier shared
between client and server which was persistent across resumption.
In the latest version of TLS (1.3) or TLS 1.2 with session tickets, the
notion of session identifiers is undefined and cannot be relied for uniquely
identifying sessions across client and server.
</p>
<p>In client side this function returns the identifier returned by the
server, and cannot be assumed to have any relation to session resumption.
In server side this function is guaranteed to return a persistent
identifier of the session since GnuTLS 3.6.4, which may not necessarily
map into the TLS session ID value. Prior to that version the value
could only be considered a persistent identifier, under TLS1.2 or earlier
and when no session tickets were in use.
</p>
<p>The session identifier value returned is always less than
<code class="code">GNUTLS_MAX_SESSION_ID_SIZE</code>  and should be treated as constant.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise
an error code is returned.
</p>
<p><strong class="strong">Since:</strong> 3.1.4
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsession_005fget_005fkeylog_005ffunction-1"><span>gnutls_session_get_keylog_function<a class="copiable-link" href="#gnutls_005fsession_005fget_005fkeylog_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsession_005fget_005fkeylog_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsession_005fget_005fkeylog_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">gnutls_keylog_func</code> <strong class="def-name">gnutls_session_get_keylog_function</strong> <code class="def-code-arguments">(const gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fsession_005fget_005fkeylog_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is <code class="code">gnutls_session_t</code>  type
</p>
<p>This function will return the callback function set using
<code class="code">gnutls_session_set_keylog_function()</code> .
</p>
<p><strong class="strong">Returns:</strong> The function set or <code class="code">NULL</code>  otherwise.
</p>
<p><strong class="strong">Since:</strong> 3.6.13
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsession_005fget_005fmaster_005fsecret-1"><span>gnutls_session_get_master_secret<a class="copiable-link" href="#gnutls_005fsession_005fget_005fmaster_005fsecret-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsession_005fget_005fmaster_005fsecret"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsession_005fget_005fmaster_005fsecret"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_session_get_master_secret</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_datum_t * <var class="var">secret</var>)</code><a class="copiable-link" href="#index-gnutls_005fsession_005fget_005fmaster_005fsecret"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">secret</var>: the session&rsquo;s master secret
</p>
<p>This function returns pointers to the master secret
used in the TLS session. The pointers are not to be modified or deallocated.
</p>
<p>This function is only applicable under TLS 1.2 or earlier versions.
</p>
<p><strong class="strong">Since:</strong> 3.5.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsession_005fget_005fptr-1"><span>gnutls_session_get_ptr<a class="copiable-link" href="#gnutls_005fsession_005fget_005fptr-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsession_005fget_005fptr"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsession_005fget_005fptr"><span class="category-def">Function: </span><span><code class="def-type">void *</code> <strong class="def-name">gnutls_session_get_ptr</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fsession_005fget_005fptr"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>Get user pointer for session.  Useful in callbacks.  This is the
pointer set with <code class="code">gnutls_session_set_ptr()</code> .
</p>
<p><strong class="strong">Returns:</strong> the user given pointer from the session structure, or
<code class="code">NULL</code>  if it was never set.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsession_005fget_005frandom-1"><span>gnutls_session_get_random<a class="copiable-link" href="#gnutls_005fsession_005fget_005frandom-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsession_005fget_005frandom"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsession_005fget_005frandom"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_session_get_random</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_datum_t * <var class="var">client</var>, gnutls_datum_t * <var class="var">server</var>)</code><a class="copiable-link" href="#index-gnutls_005fsession_005fget_005frandom"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">client</var>: the client part of the random
</p>
<p><var class="var">server</var>: the server part of the random
</p>
<p>This function returns pointers to the client and server
random fields used in the TLS handshake. The pointers are
not to be modified or deallocated.
</p>
<p>If a client random value has not yet been established, the output
will be garbage.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsession_005fget_005fverify_005fcert_005fstatus-1"><span>gnutls_session_get_verify_cert_status<a class="copiable-link" href="#gnutls_005fsession_005fget_005fverify_005fcert_005fstatus-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsession_005fget_005fverify_005fcert_005fstatus"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsession_005fget_005fverify_005fcert_005fstatus"><span class="category-def">Function: </span><span><code class="def-type">unsigned int</code> <strong class="def-name">gnutls_session_get_verify_cert_status</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fsession_005fget_005fverify_005fcert_005fstatus"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a gnutls session
</p>
<p>This function returns the status of the verification when initiated
via auto-verification, i.e., by <code class="code">gnutls_session_set_verify_cert2()</code>  or
<code class="code">gnutls_session_set_verify_cert()</code> . If no certificate verification
was occurred then the return value would be set to ((unsigned int)-1).
</p>
<p>The certificate verification status is the same as in <code class="code">gnutls_certificate_verify_peers()</code> .
</p>
<p><strong class="strong">Returns:</strong> the certificate verification status.
</p>
<p><strong class="strong">Since:</strong> 3.4.6
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsession_005fis_005fresumed-1"><span>gnutls_session_is_resumed<a class="copiable-link" href="#gnutls_005fsession_005fis_005fresumed-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsession_005fis_005fresumed"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsession_005fis_005fresumed-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_session_is_resumed</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fsession_005fis_005fresumed-1"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>Checks whether session is resumed or not. This is functional
for both server and client side.
</p>
<p><strong class="strong">Returns:</strong> non zero if this session is resumed, or a zero if this is
a new session.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsession_005fkey_005fupdate-1"><span>gnutls_session_key_update<a class="copiable-link" href="#gnutls_005fsession_005fkey_005fupdate-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsession_005fkey_005fupdate"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsession_005fkey_005fupdate"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_session_key_update</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, unsigned <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fsession_005fkey_005fupdate"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">flags</var>: zero of <code class="code">GNUTLS_KU_PEER</code> 
</p>
<p>This function will update/refresh the session keys when the
TLS protocol is 1.3 or better. The peer is notified of the
update by sending a message, so this function should be
treated similarly to <code class="code">gnutls_record_send()</code>  &ndash;i.e., it may
return <code class="code">GNUTLS_E_AGAIN</code>  or <code class="code">GNUTLS_E_INTERRUPTED</code> .
</p>
<p>When this flag <code class="code">GNUTLS_KU_PEER</code>  is specified, this function
in addition to updating the local keys, will ask the peer to
refresh its keys too.
</p>
<p>If the negotiated version is not TLS 1.3 or better this
function will return <code class="code">GNUTLS_E_INVALID_REQUEST</code> .
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.6.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsession_005fresumption_005frequested-1"><span>gnutls_session_resumption_requested<a class="copiable-link" href="#gnutls_005fsession_005fresumption_005frequested-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsession_005fresumption_005frequested"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsession_005fresumption_005frequested-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_session_resumption_requested</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fsession_005fresumption_005frequested-1"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>Check whether the client has asked for session resumption.
This function is valid only on server side.
</p>
<p><strong class="strong">Returns:</strong> non zero if session resumption was asked, or a zero if not.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsession_005fset_005fdata-1"><span>gnutls_session_set_data<a class="copiable-link" href="#gnutls_005fsession_005fset_005fdata-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsession_005fset_005fdata"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsession_005fset_005fdata"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_session_set_data</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, const void * <var class="var">session_data</var>, size_t <var class="var">session_data_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fsession_005fset_005fdata"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">session_data</var>: is a pointer to space to hold the session.
</p>
<p><var class="var">session_data_size</var>: is the session&rsquo;s size
</p>
<p>Sets all session parameters, in order to resume a previously
established session.  The session data given must be the one
returned by <code class="code">gnutls_session_get_data()</code> .  This function should be
called before <code class="code">gnutls_handshake()</code> .
</p>
<p>Keep in mind that session resuming is advisory. The server may
choose not to resume the session, thus a full handshake will be
performed.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise
an error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsession_005fset_005fid-1"><span>gnutls_session_set_id<a class="copiable-link" href="#gnutls_005fsession_005fset_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsession_005fset_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsession_005fset_005fid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_session_set_id</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, const gnutls_datum_t * <var class="var">sid</var>)</code><a class="copiable-link" href="#index-gnutls_005fsession_005fset_005fid"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">sid</var>: the session identifier
</p>
<p>This function sets the session ID to be used in a client hello.
This is a function intended for exceptional uses. Do not use this
function unless you are implementing a custom protocol.
</p>
<p>To set session resumption parameters use <code class="code">gnutls_session_set_data()</code>  instead.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise
an error code is returned.
</p>
<p><strong class="strong">Since:</strong> 3.2.1
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsession_005fset_005fkeylog_005ffunction-1"><span>gnutls_session_set_keylog_function<a class="copiable-link" href="#gnutls_005fsession_005fset_005fkeylog_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsession_005fset_005fkeylog_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsession_005fset_005fkeylog_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_session_set_keylog_function</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_keylog_func <var class="var">func</var>)</code><a class="copiable-link" href="#index-gnutls_005fsession_005fset_005fkeylog_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is <code class="code">gnutls_session_t</code>  type
</p>
<p><var class="var">func</var>: is the function to be called
</p>
<p>This function will set a callback to be called when a new secret is
derived and installed during handshake.
</p>
<p><strong class="strong">Since:</strong> 3.6.13
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsession_005fset_005fpremaster-1"><span>gnutls_session_set_premaster<a class="copiable-link" href="#gnutls_005fsession_005fset_005fpremaster-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsession_005fset_005fpremaster"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsession_005fset_005fpremaster"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_session_set_premaster</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, unsigned int <var class="var">entity</var>, gnutls_protocol_t <var class="var">version</var>, gnutls_kx_algorithm_t <var class="var">kx</var>, gnutls_cipher_algorithm_t <var class="var">cipher</var>, gnutls_mac_algorithm_t <var class="var">mac</var>, gnutls_compression_method_t <var class="var">comp</var>, const gnutls_datum_t * <var class="var">master</var>, const gnutls_datum_t * <var class="var">session_id</var>)</code><a class="copiable-link" href="#index-gnutls_005fsession_005fset_005fpremaster"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">entity</var>: GNUTLS_SERVER or GNUTLS_CLIENT
</p>
<p><var class="var">version</var>: the TLS protocol version
</p>
<p><var class="var">kx</var>: the key exchange method
</p>
<p><var class="var">cipher</var>: the cipher
</p>
<p><var class="var">mac</var>: the MAC algorithm
</p>
<p><var class="var">comp</var>: the compression method (ignored)
</p>
<p><var class="var">master</var>: the master key to use
</p>
<p><var class="var">session_id</var>: the session identifier
</p>
<p>This function sets the premaster secret in a session. This is
a function intended for exceptional uses. Do not use this
function unless you are implementing a legacy protocol.
Use <code class="code">gnutls_session_set_data()</code>  instead.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise
an error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsession_005fset_005fptr-1"><span>gnutls_session_set_ptr<a class="copiable-link" href="#gnutls_005fsession_005fset_005fptr-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsession_005fset_005fptr"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsession_005fset_005fptr"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_session_set_ptr</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, void * <var class="var">ptr</var>)</code><a class="copiable-link" href="#index-gnutls_005fsession_005fset_005fptr"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">ptr</var>: is the user pointer
</p>
<p>This function will set (associate) the user given pointer  <code class="code">ptr</code> to
the session structure.  This pointer can be accessed with
<code class="code">gnutls_session_get_ptr()</code> .
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsession_005fset_005fverify_005fcert-1"><span>gnutls_session_set_verify_cert<a class="copiable-link" href="#gnutls_005fsession_005fset_005fverify_005fcert-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsession_005fset_005fverify_005fcert"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsession_005fset_005fverify_005fcert-1"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_session_set_verify_cert</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, const char * <var class="var">hostname</var>, unsigned <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fsession_005fset_005fverify_005fcert-1"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a gnutls session
</p>
<p><var class="var">hostname</var>: is the expected name of the peer; may be <code class="code">NULL</code> 
</p>
<p><var class="var">flags</var>: flags for certificate verification &ndash; <code class="code">gnutls_certificate_verify_flags</code> 
</p>
<p>This function instructs GnuTLS to verify the peer&rsquo;s certificate
using the provided hostname. If the verification fails the handshake
will also fail with <code class="code">GNUTLS_E_CERTIFICATE_VERIFICATION_ERROR</code> . In that
case the verification result can be obtained using <code class="code">gnutls_session_get_verify_cert_status()</code> .
</p>
<p>The  <code class="code">hostname</code> pointer provided must remain valid for the lifetime
of the session. More precisely it should be available during any subsequent
handshakes. If no hostname is provided, no hostname verification
will be performed. For a more advanced verification function check
<code class="code">gnutls_session_set_verify_cert2()</code> .
</p>
<p>If  <code class="code">flags</code> is provided which contain a profile, this function should be
called after any session priority setting functions.
</p>
<p>The <code class="code">gnutls_session_set_verify_cert()</code>  function is intended to be used by TLS
clients to verify the server&rsquo;s certificate.
</p>
<p><strong class="strong">Since:</strong> 3.4.6
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsession_005fset_005fverify_005fcert2-1"><span>gnutls_session_set_verify_cert2<a class="copiable-link" href="#gnutls_005fsession_005fset_005fverify_005fcert2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsession_005fset_005fverify_005fcert2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsession_005fset_005fverify_005fcert2"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_session_set_verify_cert2</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_typed_vdata_st * <var class="var">data</var>, unsigned <var class="var">elements</var>, unsigned <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fsession_005fset_005fverify_005fcert2"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a gnutls session
</p>
<p><var class="var">data</var>: an array of typed data
</p>
<p><var class="var">elements</var>: the number of data elements
</p>
<p><var class="var">flags</var>: flags for certificate verification &ndash; <code class="code">gnutls_certificate_verify_flags</code> 
</p>
<p>This function instructs GnuTLS to verify the peer&rsquo;s certificate
using the provided typed data information. If the verification fails the handshake
will also fail with <code class="code">GNUTLS_E_CERTIFICATE_VERIFICATION_ERROR</code> . In that
case the verification result can be obtained using <code class="code">gnutls_session_get_verify_cert_status()</code> .
</p>
<p>The acceptable typed data are the same as in <code class="code">gnutls_certificate_verify_peers()</code> ,
and once set must remain valid for the lifetime of the session. More precisely
they should be available during any subsequent handshakes.
</p>
<p>If  <code class="code">flags</code> is provided which contain a profile, this function should be
called after any session priority setting functions.
</p>
<p><strong class="strong">Since:</strong> 3.4.6
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsession_005fset_005fverify_005ffunction-1"><span>gnutls_session_set_verify_function<a class="copiable-link" href="#gnutls_005fsession_005fset_005fverify_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsession_005fset_005fverify_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsession_005fset_005fverify_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_session_set_verify_function</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_certificate_verify_function * <var class="var">func</var>)</code><a class="copiable-link" href="#index-gnutls_005fsession_005fset_005fverify_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">func</var>: is the callback function
</p>
<p>This function sets a callback to be called when peer&rsquo;s certificate
has been received in order to verify it on receipt rather than
doing after the handshake is completed. This overrides any callback
set using <code class="code">gnutls_certificate_set_verify_function()</code> .
</p>
<p>The callback&rsquo;s function prototype is:
int (*callback)(gnutls_session_t);
</p>
<p>If the callback function is provided then gnutls will call it, in the
handshake, just after the certificate message has been received.
To verify or obtain the certificate the <code class="code">gnutls_certificate_verify_peers2()</code> ,
<code class="code">gnutls_certificate_type_get()</code> , <code class="code">gnutls_certificate_get_peers()</code>  functions
can be used.
</p>
<p>The callback function should return 0 for the handshake to continue
or non-zero to terminate.
</p>
<p><strong class="strong">Since:</strong> 3.4.6
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsession_005fsupplemental_005fregister-1"><span>gnutls_session_supplemental_register<a class="copiable-link" href="#gnutls_005fsession_005fsupplemental_005fregister-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsession_005fsupplemental_005fregister"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsession_005fsupplemental_005fregister"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_session_supplemental_register</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, const char * <var class="var">name</var>, gnutls_supplemental_data_format_type_t <var class="var">type</var>, gnutls_supp_recv_func <var class="var">recv_func</var>, gnutls_supp_send_func <var class="var">send_func</var>, unsigned <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fsession_005fsupplemental_005fregister"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: the session for which this will be registered
</p>
<p><var class="var">name</var>: the name of the supplemental data to register
</p>
<p><var class="var">type</var>: the type of the supplemental data format
</p>
<p><var class="var">recv_func</var>: the function to receive the data
</p>
<p><var class="var">send_func</var>: the function to send the data
</p>
<p><var class="var">flags</var>: must be zero
</p>
<p>This function will register a new supplemental data type (rfc4680).
The registered supplemental functions will be used for that specific
session. The provided  <code class="code">type</code> must be an unassigned type in
<code class="code">gnutls_supplemental_data_format_type_t</code> .
</p>
<p>If the type is already registered or handled by GnuTLS internally
<code class="code">GNUTLS_E_ALREADY_REGISTERED</code>  will be returned.
</p>
<p>As supplemental data are not defined under TLS 1.3, this function will
disable TLS 1.3 support for the given session.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.5.5
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsession_005fticket_005fenable_005fclient-1"><span>gnutls_session_ticket_enable_client<a class="copiable-link" href="#gnutls_005fsession_005fticket_005fenable_005fclient-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsession_005fticket_005fenable_005fclient"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsession_005fticket_005fenable_005fclient"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_session_ticket_enable_client</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fsession_005fticket_005fenable_005fclient"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>Request that the client should attempt session resumption using
SessionTicket. This call is typically unnecessary as session
tickets are enabled by default.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, or an
error code.
</p>
<p><strong class="strong">Since:</strong> 2.10.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsession_005fticket_005fenable_005fserver-1"><span>gnutls_session_ticket_enable_server<a class="copiable-link" href="#gnutls_005fsession_005fticket_005fenable_005fserver-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsession_005fticket_005fenable_005fserver"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsession_005fticket_005fenable_005fserver-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_session_ticket_enable_server</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, const gnutls_datum_t * <var class="var">key</var>)</code><a class="copiable-link" href="#index-gnutls_005fsession_005fticket_005fenable_005fserver-1"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">key</var>: key to encrypt session parameters.
</p>
<p>Request that the server should attempt session resumption using
session tickets, i.e., by delegating storage to the client.
 <code class="code">key</code> must be initialized using <code class="code">gnutls_session_ticket_key_generate()</code> .
To avoid leaking that key, use <code class="code">gnutls_memset()</code>  prior to
releasing it.
</p>
<p>The default ticket expiration time can be overridden using
<code class="code">gnutls_db_set_cache_expiration()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, or an
error code.
</p>
<p><strong class="strong">Since:</strong> 2.10.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsession_005fticket_005fkey_005fgenerate-1"><span>gnutls_session_ticket_key_generate<a class="copiable-link" href="#gnutls_005fsession_005fticket_005fkey_005fgenerate-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsession_005fticket_005fkey_005fgenerate"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsession_005fticket_005fkey_005fgenerate-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_session_ticket_key_generate</strong> <code class="def-code-arguments">(gnutls_datum_t * <var class="var">key</var>)</code><a class="copiable-link" href="#index-gnutls_005fsession_005fticket_005fkey_005fgenerate-1"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: is a pointer to a <code class="code">gnutls_datum_t</code>  which will contain a newly
created key.
</p>
<p>Generate a random key to encrypt security parameters within
SessionTicket.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, or an
error code.
</p>
<p><strong class="strong">Since:</strong> 2.10.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsession_005fticket_005fsend-1"><span>gnutls_session_ticket_send<a class="copiable-link" href="#gnutls_005fsession_005fticket_005fsend-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsession_005fticket_005fsend"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsession_005fticket_005fsend-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_session_ticket_send</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, unsigned <var class="var">nr</var>, unsigned <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fsession_005fticket_005fsend-1"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">nr</var>: the number of tickets to send
</p>
<p><var class="var">flags</var>: must be zero
</p>
<p>Sends a fresh session ticket to the peer. This is relevant only
in server side under TLS1.3. This function may also return <code class="code">GNUTLS_E_AGAIN</code> 
or <code class="code">GNUTLS_E_INTERRUPTED</code>  and in that case it must be called again.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, or a negative error code.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fset_005fdefault_005fpriority-1"><span>gnutls_set_default_priority<a class="copiable-link" href="#gnutls_005fset_005fdefault_005fpriority-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fset_005fdefault_005fpriority"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fset_005fdefault_005fpriority"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_set_default_priority</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fset_005fdefault_005fpriority"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>Sets the default priority on the ciphers, key exchange methods,
and macs. This is the recommended method of
setting the defaults, in order to promote consistency between applications
using GnuTLS, and to allow GnuTLS using applications to update settings
in par with the library. For client applications which require
maximum compatibility consider calling <code class="code">gnutls_session_enable_compatibility_mode()</code> 
after this function.
</p>
<p>For an application to specify additional options to priority string
consider using <code class="code">gnutls_set_default_priority_append()</code> .
</p>
<p>To allow a user to override the defaults (e.g., when a user interface
or configuration file is available), the functions
<code class="code">gnutls_priority_set_direct()</code>  or <code class="code">gnutls_priority_set()</code>  can
be used.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, or an error code.
</p>
<p><strong class="strong">Since:</strong> 2.1.4
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fset_005fdefault_005fpriority_005fappend-1"><span>gnutls_set_default_priority_append<a class="copiable-link" href="#gnutls_005fset_005fdefault_005fpriority_005fappend-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fset_005fdefault_005fpriority_005fappend"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fset_005fdefault_005fpriority_005fappend"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_set_default_priority_append</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, const char * <var class="var">add_prio</var>, const char ** <var class="var">err_pos</var>, unsigned <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fset_005fdefault_005fpriority_005fappend"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">add_prio</var>: is a string describing priorities to be appended to default
</p>
<p><var class="var">err_pos</var>: In case of an error this will have the position in the string the error occurred
</p>
<p><var class="var">flags</var>: must be zero
</p>
<p>Sets the default priority on the ciphers, key exchange methods,
and macs with the additional options in  <code class="code">add_prio</code> . This is the recommended method of
setting the defaults when only few additional options are to be added. This promotes
consistency between applications using GnuTLS, and allows GnuTLS using applications
to update settings in par with the library.
</p>
<p>The  <code class="code">add_prio</code> string should start as a normal priority string, e.g.,
&rsquo;-VERS-TLS-ALL:+VERS-TLS1.3:%COMPAT&rsquo; or &rsquo;%FORCE_ETM&rsquo;. That is, it must not start
with &rsquo;:&rsquo;.
</p>
<p>To allow a user to override the defaults (e.g., when a user interface
or configuration file is available), the functions
<code class="code">gnutls_priority_set_direct()</code>  or <code class="code">gnutls_priority_set()</code>  can
be used.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, or an error code.
</p>
<p><strong class="strong">Since:</strong> 3.6.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsign_005falgorithm_005fget-1"><span>gnutls_sign_algorithm_get<a class="copiable-link" href="#gnutls_005fsign_005falgorithm_005fget-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsign_005falgorithm_005fget"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsign_005falgorithm_005fget"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_sign_algorithm_get</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fsign_005falgorithm_005fget"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>Returns the signature algorithm that is (or will be) used in this
session by the server to sign data. This function should be
used only with TLS 1.2 or later.
</p>
<p><strong class="strong">Returns:</strong> The sign algorithm or <code class="code">GNUTLS_SIGN_UNKNOWN</code> .
</p>
<p><strong class="strong">Since:</strong> 3.1.1
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsign_005falgorithm_005fget_005fclient-1"><span>gnutls_sign_algorithm_get_client<a class="copiable-link" href="#gnutls_005fsign_005falgorithm_005fget_005fclient-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsign_005falgorithm_005fget_005fclient"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsign_005falgorithm_005fget_005fclient"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_sign_algorithm_get_client</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fsign_005falgorithm_005fget_005fclient"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>Returns the signature algorithm that is (or will be) used in this
session by the client to sign data. This function should be
used only with TLS 1.2 or later.
</p>
<p><strong class="strong">Returns:</strong> The sign algorithm or <code class="code">GNUTLS_SIGN_UNKNOWN</code> .
</p>
<p><strong class="strong">Since:</strong> 3.1.11
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsign_005falgorithm_005fget_005frequested-1"><span>gnutls_sign_algorithm_get_requested<a class="copiable-link" href="#gnutls_005fsign_005falgorithm_005fget_005frequested-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsign_005falgorithm_005fget_005frequested"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsign_005falgorithm_005fget_005frequested"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_sign_algorithm_get_requested</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, size_t <var class="var">indx</var>, gnutls_sign_algorithm_t * <var class="var">algo</var>)</code><a class="copiable-link" href="#index-gnutls_005fsign_005falgorithm_005fget_005frequested"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">indx</var>: is an index of the signature algorithm to return
</p>
<p><var class="var">algo</var>: the returned certificate type will be stored there
</p>
<p>Returns the signature algorithm specified by index that was
requested by the peer. If the specified index has no data available
this function returns <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> .  If
the negotiated TLS version does not support signature algorithms
then <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  will be returned even
for the first index.  The first index is 0.
</p>
<p>This function is useful in the certificate callback functions
to assist in selecting the correct certificate.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise
an error code is returned.
</p>
<p><strong class="strong">Since:</strong> 2.10.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsign_005fget_005fhash_005falgorithm-1"><span>gnutls_sign_get_hash_algorithm<a class="copiable-link" href="#gnutls_005fsign_005fget_005fhash_005falgorithm-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsign_005fget_005fhash_005falgorithm"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsign_005fget_005fhash_005falgorithm"><span class="category-def">Function: </span><span><code class="def-type">gnutls_digest_algorithm_t</code> <strong class="def-name">gnutls_sign_get_hash_algorithm</strong> <code class="def-code-arguments">(gnutls_sign_algorithm_t <var class="var">sign</var>)</code><a class="copiable-link" href="#index-gnutls_005fsign_005fget_005fhash_005falgorithm"> &para;</a></span></dt>
<dd><p><var class="var">sign</var>: is a signature algorithm
</p>
<p>This function returns the digest algorithm corresponding to
the given signature algorithms.
</p>
<p><strong class="strong">Since:</strong> 3.1.1
</p>
<p><strong class="strong">Returns:</strong> return a <code class="code">gnutls_digest_algorithm_t</code>  value, or <code class="code">GNUTLS_DIG_UNKNOWN</code>  on error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsign_005fget_005fid-1"><span>gnutls_sign_get_id<a class="copiable-link" href="#gnutls_005fsign_005fget_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsign_005fget_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsign_005fget_005fid"><span class="category-def">Function: </span><span><code class="def-type">gnutls_sign_algorithm_t</code> <strong class="def-name">gnutls_sign_get_id</strong> <code class="def-code-arguments">(const char * <var class="var">name</var>)</code><a class="copiable-link" href="#index-gnutls_005fsign_005fget_005fid"> &para;</a></span></dt>
<dd><p><var class="var">name</var>: is a sign algorithm name
</p>
<p>The names are compared in a case insensitive way.
</p>
<p><strong class="strong">Returns:</strong> return a <code class="code">gnutls_sign_algorithm_t</code>  value corresponding to
the specified algorithm, or <code class="code">GNUTLS_SIGN_UNKNOWN</code>  on error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsign_005fget_005fname-1"><span>gnutls_sign_get_name<a class="copiable-link" href="#gnutls_005fsign_005fget_005fname-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsign_005fget_005fname"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsign_005fget_005fname"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_sign_get_name</strong> <code class="def-code-arguments">(gnutls_sign_algorithm_t <var class="var">algorithm</var>)</code><a class="copiable-link" href="#index-gnutls_005fsign_005fget_005fname"> &para;</a></span></dt>
<dd><p><var class="var">algorithm</var>: is a sign algorithm
</p>
<p>Convert a <code class="code">gnutls_sign_algorithm_t</code>  value to a string.
</p>
<p><strong class="strong">Returns:</strong> a string that contains the name of the specified sign
algorithm, or <code class="code">NULL</code> .
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsign_005fget_005foid-1"><span>gnutls_sign_get_oid<a class="copiable-link" href="#gnutls_005fsign_005fget_005foid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsign_005fget_005foid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsign_005fget_005foid"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_sign_get_oid</strong> <code class="def-code-arguments">(gnutls_sign_algorithm_t <var class="var">sign</var>)</code><a class="copiable-link" href="#index-gnutls_005fsign_005fget_005foid"> &para;</a></span></dt>
<dd><p><var class="var">sign</var>: is a sign algorithm
</p>
<p>Convert a <code class="code">gnutls_sign_algorithm_t</code>  value to its object identifier.
</p>
<p><strong class="strong">Returns:</strong> a string that contains the object identifier of the specified sign
algorithm, or <code class="code">NULL</code> .
</p>
<p><strong class="strong">Since:</strong> 3.4.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsign_005fget_005fpk_005falgorithm-1"><span>gnutls_sign_get_pk_algorithm<a class="copiable-link" href="#gnutls_005fsign_005fget_005fpk_005falgorithm-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsign_005fget_005fpk_005falgorithm"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsign_005fget_005fpk_005falgorithm"><span class="category-def">Function: </span><span><code class="def-type">gnutls_pk_algorithm_t</code> <strong class="def-name">gnutls_sign_get_pk_algorithm</strong> <code class="def-code-arguments">(gnutls_sign_algorithm_t <var class="var">sign</var>)</code><a class="copiable-link" href="#index-gnutls_005fsign_005fget_005fpk_005falgorithm"> &para;</a></span></dt>
<dd><p><var class="var">sign</var>: is a signature algorithm
</p>
<p>This function returns the public key algorithm corresponding to
the given signature algorithms. Note that there may be multiple
public key algorithms supporting a particular signature type;
when dealing with such algorithms use instead <code class="code">gnutls_sign_supports_pk_algorithm()</code> .
</p>
<p><strong class="strong">Since:</strong> 3.1.1
</p>
<p><strong class="strong">Returns:</strong> return a <code class="code">gnutls_pk_algorithm_t</code>  value, or <code class="code">GNUTLS_PK_UNKNOWN</code>  on error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsign_005fis_005fsecure-1"><span>gnutls_sign_is_secure<a class="copiable-link" href="#gnutls_005fsign_005fis_005fsecure-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsign_005fis_005fsecure"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsign_005fis_005fsecure"><span class="category-def">Function: </span><span><code class="def-type">unsigned</code> <strong class="def-name">gnutls_sign_is_secure</strong> <code class="def-code-arguments">(gnutls_sign_algorithm_t <var class="var">algorithm</var>)</code><a class="copiable-link" href="#index-gnutls_005fsign_005fis_005fsecure"> &para;</a></span></dt>
<dd><p><var class="var">algorithm</var>: is a sign algorithm
</p>

<p><strong class="strong">Returns:</strong> Non-zero if the provided signature algorithm is considered to be secure.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsign_005fis_005fsecure2-1"><span>gnutls_sign_is_secure2<a class="copiable-link" href="#gnutls_005fsign_005fis_005fsecure2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsign_005fis_005fsecure2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsign_005fis_005fsecure2"><span class="category-def">Function: </span><span><code class="def-type">unsigned</code> <strong class="def-name">gnutls_sign_is_secure2</strong> <code class="def-code-arguments">(gnutls_sign_algorithm_t <var class="var">algorithm</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fsign_005fis_005fsecure2"> &para;</a></span></dt>
<dd><p><var class="var">algorithm</var>: is a sign algorithm
</p>
<p><var class="var">flags</var>: zero or <code class="code">GNUTLS_SIGN_FLAG_SECURE_FOR_CERTS</code> 
</p>

<p><strong class="strong">Returns:</strong> Non-zero if the provided signature algorithm is considered to be secure.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsign_005flist-1"><span>gnutls_sign_list<a class="copiable-link" href="#gnutls_005fsign_005flist-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsign_005flist"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsign_005flist"><span class="category-def">Function: </span><span><code class="def-type">const gnutls_sign_algorithm_t *</code> <strong class="def-name">gnutls_sign_list</strong> <code class="def-code-arguments">( <var class="var">void</var>)</code><a class="copiable-link" href="#index-gnutls_005fsign_005flist"> &para;</a></span></dt>
<dd>
<p>Get a list of supported public key signature algorithms.
This function is not thread safe.
</p>
<p><strong class="strong">Returns:</strong> a (0)-terminated list of <code class="code">gnutls_sign_algorithm_t</code> 
integers indicating the available ciphers.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsign_005fset_005fsecure-1"><span>gnutls_sign_set_secure<a class="copiable-link" href="#gnutls_005fsign_005fset_005fsecure-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsign_005fset_005fsecure"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsign_005fset_005fsecure"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_sign_set_secure</strong> <code class="def-code-arguments">(gnutls_sign_algorithm_t <var class="var">sign</var>, unsigned int <var class="var">secure</var>)</code><a class="copiable-link" href="#index-gnutls_005fsign_005fset_005fsecure"> &para;</a></span></dt>
<dd><p><var class="var">sign</var>: the sign algorithm
</p>
<p><var class="var">secure</var>: whether to mark the sign algorithm secure
</p>
<p>Modify the previous system wide setting that marked  <code class="code">sign</code> as secure
or insecure.  Calling this function is allowed
only if allowlisting mode is set in the configuration file,
and only if the system-wide TLS priority string
has not been initialized yet.
The intended usage is to provide applications with a way
to expressly deviate from the distribution or site defaults
inherited from the configuration file.
The modification is composable with further modifications
performed through the priority string mechanism.
</p>
<p>This function is not thread-safe and is intended to be called
in the main thread at the beginning of the process execution.
</p>
<p>Even when  <code class="code">secure</code> is true,  <code class="code">sign</code> is not marked as secure for the
use in certificates.  Use <code class="code">gnutls_sign_set_secure_for_certs()</code>  to
mark it secure as well for certificates.
</p>
<p><strong class="strong">Returns:</strong> 0 on success or negative error code otherwise.
</p>
<p><strong class="strong">Since:</strong> 3.7.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsign_005fset_005fsecure_005ffor_005fcerts-1"><span>gnutls_sign_set_secure_for_certs<a class="copiable-link" href="#gnutls_005fsign_005fset_005fsecure_005ffor_005fcerts-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsign_005fset_005fsecure_005ffor_005fcerts"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsign_005fset_005fsecure_005ffor_005fcerts"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_sign_set_secure_for_certs</strong> <code class="def-code-arguments">(gnutls_sign_algorithm_t <var class="var">sign</var>, unsigned int <var class="var">secure</var>)</code><a class="copiable-link" href="#index-gnutls_005fsign_005fset_005fsecure_005ffor_005fcerts"> &para;</a></span></dt>
<dd><p><var class="var">sign</var>: the sign algorithm
</p>
<p><var class="var">secure</var>: whether to mark the sign algorithm secure for certificates
</p>
<p>Modify the previous system wide setting that marked  <code class="code">sign</code> as secure
or insecure for the use in certificates.  Calling this function is allowed
only if allowlisting mode is set in the configuration file,
and only if the system-wide TLS priority string
has not been initialized yet.
The intended usage is to provide applications with a way
to expressly deviate from the distribution or site defaults
inherited from the configuration file.
The modification is composable with further modifications
performed through the priority string mechanism.
</p>
<p>This function is not thread-safe and is intended to be called
in the main thread at the beginning of the process execution.
When  <code class="code">secure</code> is true,  <code class="code">sign</code> is marked as secure for any use unlike
<code class="code">gnutls_sign_set_secure()</code> .  Otherwise, it is marked as insecure only
for the use in certificates.  Use <code class="code">gnutls_sign_set_secure()</code>  to mark
it insecure for any uses.
</p>
<p><strong class="strong">Returns:</strong> 0 on success or negative error code otherwise.
</p>
<p><strong class="strong">Since:</strong> 3.7.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsign_005fsupports_005fpk_005falgorithm-1"><span>gnutls_sign_supports_pk_algorithm<a class="copiable-link" href="#gnutls_005fsign_005fsupports_005fpk_005falgorithm-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsign_005fsupports_005fpk_005falgorithm"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsign_005fsupports_005fpk_005falgorithm"><span class="category-def">Function: </span><span><code class="def-type">unsigned</code> <strong class="def-name">gnutls_sign_supports_pk_algorithm</strong> <code class="def-code-arguments">(gnutls_sign_algorithm_t <var class="var">sign</var>, gnutls_pk_algorithm_t <var class="var">pk</var>)</code><a class="copiable-link" href="#index-gnutls_005fsign_005fsupports_005fpk_005falgorithm"> &para;</a></span></dt>
<dd><p><var class="var">sign</var>: is a signature algorithm
</p>
<p><var class="var">pk</var>: is a public key algorithm
</p>
<p>This function returns non-zero if the public key algorithm corresponds to
the given signature algorithm. That is, if that signature can be generated
from the given private key algorithm.
</p>
<p><strong class="strong">Since:</strong> 3.6.0
</p>
<p><strong class="strong">Returns:</strong> return non-zero when the provided algorithms are compatible.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsrp_005fallocate_005fclient_005fcredentials-1"><span>gnutls_srp_allocate_client_credentials<a class="copiable-link" href="#gnutls_005fsrp_005fallocate_005fclient_005fcredentials-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsrp_005fallocate_005fclient_005fcredentials"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsrp_005fallocate_005fclient_005fcredentials"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_srp_allocate_client_credentials</strong> <code class="def-code-arguments">(gnutls_srp_client_credentials_t * <var class="var">sc</var>)</code><a class="copiable-link" href="#index-gnutls_005fsrp_005fallocate_005fclient_005fcredentials"> &para;</a></span></dt>
<dd><p><var class="var">sc</var>: is a pointer to a <code class="code">gnutls_srp_server_credentials_t</code>  type.
</p>
<p>Allocate a gnutls_srp_client_credentials_t structure.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, or an
error code.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsrp_005fallocate_005fserver_005fcredentials-1"><span>gnutls_srp_allocate_server_credentials<a class="copiable-link" href="#gnutls_005fsrp_005fallocate_005fserver_005fcredentials-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsrp_005fallocate_005fserver_005fcredentials"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsrp_005fallocate_005fserver_005fcredentials"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_srp_allocate_server_credentials</strong> <code class="def-code-arguments">(gnutls_srp_server_credentials_t * <var class="var">sc</var>)</code><a class="copiable-link" href="#index-gnutls_005fsrp_005fallocate_005fserver_005fcredentials"> &para;</a></span></dt>
<dd><p><var class="var">sc</var>: is a pointer to a <code class="code">gnutls_srp_server_credentials_t</code>  type.
</p>
<p>Allocate a gnutls_srp_server_credentials_t structure.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, or an
error code.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsrp_005fbase64_005fdecode-1"><span>gnutls_srp_base64_decode<a class="copiable-link" href="#gnutls_005fsrp_005fbase64_005fdecode-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsrp_005fbase64_005fdecode"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsrp_005fbase64_005fdecode"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_srp_base64_decode</strong> <code class="def-code-arguments">(const gnutls_datum_t * <var class="var">b64_data</var>, char * <var class="var">result</var>, size_t * <var class="var">result_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fsrp_005fbase64_005fdecode"> &para;</a></span></dt>
<dd><p><var class="var">b64_data</var>: contain the encoded data
</p>
<p><var class="var">result</var>: the place where decoded data will be copied
</p>
<p><var class="var">result_size</var>: holds the size of the result
</p>
<p>This function will decode the given encoded data, using the base64
encoding found in libsrp.
</p>
<p>Note that  <code class="code">b64_data</code> should be null terminated.
</p>
<p>Warning!  This base64 encoding is not the &quot;standard&quot; encoding, so
do not use it for non-SRP purposes.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  if the buffer given is not
long enough, or 0 on success.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsrp_005fbase64_005fdecode2-1"><span>gnutls_srp_base64_decode2<a class="copiable-link" href="#gnutls_005fsrp_005fbase64_005fdecode2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsrp_005fbase64_005fdecode2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsrp_005fbase64_005fdecode2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_srp_base64_decode2</strong> <code class="def-code-arguments">(const gnutls_datum_t * <var class="var">b64_data</var>, gnutls_datum_t * <var class="var">result</var>)</code><a class="copiable-link" href="#index-gnutls_005fsrp_005fbase64_005fdecode2"> &para;</a></span></dt>
<dd><p><var class="var">b64_data</var>: contains the encoded data
</p>
<p><var class="var">result</var>: the place where decoded data lie
</p>
<p>This function will decode the given encoded data. The decoded data
will be allocated, and stored into result.  It will decode using
the base64 algorithm as used in libsrp.
</p>
<p>You should use <code class="code">gnutls_free()</code>  to free the returned data.
</p>
<p>Warning!  This base64 encoding is not the &quot;standard&quot; encoding, so
do not use it for non-SRP purposes.
</p>
<p><strong class="strong">Returns:</strong> 0 on success, or an error code.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsrp_005fbase64_005fencode-1"><span>gnutls_srp_base64_encode<a class="copiable-link" href="#gnutls_005fsrp_005fbase64_005fencode-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsrp_005fbase64_005fencode"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsrp_005fbase64_005fencode"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_srp_base64_encode</strong> <code class="def-code-arguments">(const gnutls_datum_t * <var class="var">data</var>, char * <var class="var">result</var>, size_t * <var class="var">result_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fsrp_005fbase64_005fencode"> &para;</a></span></dt>
<dd><p><var class="var">data</var>: contain the raw data
</p>
<p><var class="var">result</var>: the place where base64 data will be copied
</p>
<p><var class="var">result_size</var>: holds the size of the result
</p>
<p>This function will convert the given data to printable data, using
the base64 encoding, as used in the libsrp.  This is the encoding
used in SRP password files.  If the provided buffer is not long
enough GNUTLS_E_SHORT_MEMORY_BUFFER is returned.
</p>
<p>Warning!  This base64 encoding is not the &quot;standard&quot; encoding, so
do not use it for non-SRP purposes.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  if the buffer given is not
long enough, or 0 on success.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsrp_005fbase64_005fencode2-1"><span>gnutls_srp_base64_encode2<a class="copiable-link" href="#gnutls_005fsrp_005fbase64_005fencode2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsrp_005fbase64_005fencode2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsrp_005fbase64_005fencode2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_srp_base64_encode2</strong> <code class="def-code-arguments">(const gnutls_datum_t * <var class="var">data</var>, gnutls_datum_t * <var class="var">result</var>)</code><a class="copiable-link" href="#index-gnutls_005fsrp_005fbase64_005fencode2"> &para;</a></span></dt>
<dd><p><var class="var">data</var>: contains the raw data
</p>
<p><var class="var">result</var>: will hold the newly allocated encoded data
</p>
<p>This function will convert the given data to printable data, using
the base64 encoding.  This is the encoding used in SRP password
files.  This function will allocate the required memory to hold
the encoded data.
</p>
<p>You should use <code class="code">gnutls_free()</code>  to free the returned data.
</p>
<p>Warning!  This base64 encoding is not the &quot;standard&quot; encoding, so
do not use it for non-SRP purposes.
</p>
<p><strong class="strong">Returns:</strong> 0 on success, or an error code.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsrp_005ffree_005fclient_005fcredentials-1"><span>gnutls_srp_free_client_credentials<a class="copiable-link" href="#gnutls_005fsrp_005ffree_005fclient_005fcredentials-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsrp_005ffree_005fclient_005fcredentials"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsrp_005ffree_005fclient_005fcredentials"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_srp_free_client_credentials</strong> <code class="def-code-arguments">(gnutls_srp_client_credentials_t <var class="var">sc</var>)</code><a class="copiable-link" href="#index-gnutls_005fsrp_005ffree_005fclient_005fcredentials"> &para;</a></span></dt>
<dd><p><var class="var">sc</var>: is a <code class="code">gnutls_srp_client_credentials_t</code>  type.
</p>
<p>Free a gnutls_srp_client_credentials_t structure.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsrp_005ffree_005fserver_005fcredentials-1"><span>gnutls_srp_free_server_credentials<a class="copiable-link" href="#gnutls_005fsrp_005ffree_005fserver_005fcredentials-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsrp_005ffree_005fserver_005fcredentials"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsrp_005ffree_005fserver_005fcredentials"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_srp_free_server_credentials</strong> <code class="def-code-arguments">(gnutls_srp_server_credentials_t <var class="var">sc</var>)</code><a class="copiable-link" href="#index-gnutls_005fsrp_005ffree_005fserver_005fcredentials"> &para;</a></span></dt>
<dd><p><var class="var">sc</var>: is a <code class="code">gnutls_srp_server_credentials_t</code>  type.
</p>
<p>Free a gnutls_srp_server_credentials_t structure.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsrp_005fserver_005fget_005fusername-1"><span>gnutls_srp_server_get_username<a class="copiable-link" href="#gnutls_005fsrp_005fserver_005fget_005fusername-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsrp_005fserver_005fget_005fusername"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsrp_005fserver_005fget_005fusername"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_srp_server_get_username</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fsrp_005fserver_005fget_005fusername"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a gnutls session
</p>
<p>This function will return the username of the peer.  This should
only be called in case of SRP authentication and in case of a
server.  Returns NULL in case of an error.
</p>
<p><strong class="strong">Returns:</strong> SRP username of the peer, or NULL in case of error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsrp_005fset_005fclient_005fcredentials-1"><span>gnutls_srp_set_client_credentials<a class="copiable-link" href="#gnutls_005fsrp_005fset_005fclient_005fcredentials-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsrp_005fset_005fclient_005fcredentials"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsrp_005fset_005fclient_005fcredentials"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_srp_set_client_credentials</strong> <code class="def-code-arguments">(gnutls_srp_client_credentials_t <var class="var">res</var>, const char * <var class="var">username</var>, const char * <var class="var">password</var>)</code><a class="copiable-link" href="#index-gnutls_005fsrp_005fset_005fclient_005fcredentials"> &para;</a></span></dt>
<dd><p><var class="var">res</var>: is a <code class="code">gnutls_srp_client_credentials_t</code>  type.
</p>
<p><var class="var">username</var>: is the user&rsquo;s userid
</p>
<p><var class="var">password</var>: is the user&rsquo;s password
</p>
<p>This function sets the username and password, in a
<code class="code">gnutls_srp_client_credentials_t</code>  type.  Those will be used in
SRP authentication.   <code class="code">username</code> should be an ASCII string or UTF-8
string. In case of a UTF-8 string it is recommended to be following
the PRECIS framework for usernames (rfc8265). The password can
be in ASCII format, or normalized using <code class="code">gnutls_utf8_password_normalize()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, or an
error code.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsrp_005fset_005fclient_005fcredentials_005ffunction-1"><span>gnutls_srp_set_client_credentials_function<a class="copiable-link" href="#gnutls_005fsrp_005fset_005fclient_005fcredentials_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsrp_005fset_005fclient_005fcredentials_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsrp_005fset_005fclient_005fcredentials_005ffunction-1"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_srp_set_client_credentials_function</strong> <code class="def-code-arguments">(gnutls_srp_client_credentials_t <var class="var">cred</var>, gnutls_srp_client_credentials_function * <var class="var">func</var>)</code><a class="copiable-link" href="#index-gnutls_005fsrp_005fset_005fclient_005fcredentials_005ffunction-1"> &para;</a></span></dt>
<dd><p><var class="var">cred</var>: is a <code class="code">gnutls_srp_server_credentials_t</code>  type.
</p>
<p><var class="var">func</var>: is the callback function
</p>
<p>This function can be used to set a callback to retrieve the
username and password for client SRP authentication.  The
callback&rsquo;s function form is:
</p>
<p>int (*callback)(gnutls_session_t, char** username, char**password);
</p>
<p>The  <code class="code">username</code> and  <code class="code">password</code> must be allocated using
<code class="code">gnutls_malloc()</code> .
</p>
<p>The  <code class="code">username</code> should be an ASCII string or UTF-8
string. In case of a UTF-8 string it is recommended to be following
the PRECIS framework for usernames (rfc8265). The password can
be in ASCII format, or normalized using <code class="code">gnutls_utf8_password_normalize()</code> .
</p>
<p>The callback function will be called once per handshake before the
initial hello message is sent.
</p>
<p>The callback should not return a negative error code the second
time called, since the handshake procedure will be aborted.
</p>
<p>The callback function should return 0 on success.
-1 indicates an error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsrp_005fset_005fprime_005fbits-1"><span>gnutls_srp_set_prime_bits<a class="copiable-link" href="#gnutls_005fsrp_005fset_005fprime_005fbits-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsrp_005fset_005fprime_005fbits"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsrp_005fset_005fprime_005fbits"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_srp_set_prime_bits</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, unsigned int <var class="var">bits</var>)</code><a class="copiable-link" href="#index-gnutls_005fsrp_005fset_005fprime_005fbits"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">bits</var>: is the number of bits
</p>
<p>This function sets the minimum accepted number of bits, for use in
an SRP key exchange.  If zero, the default 2048 bits will be used.
</p>
<p>In the client side it sets the minimum accepted number of bits.  If
a server sends a prime with less bits than that
<code class="code">GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER</code>  will be returned by the
handshake.
</p>
<p>This function has no effect in server side.
</p>
<p><strong class="strong">Since:</strong> 2.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsrp_005fset_005fserver_005fcredentials_005ffile-1"><span>gnutls_srp_set_server_credentials_file<a class="copiable-link" href="#gnutls_005fsrp_005fset_005fserver_005fcredentials_005ffile-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsrp_005fset_005fserver_005fcredentials_005ffile"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsrp_005fset_005fserver_005fcredentials_005ffile-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_srp_set_server_credentials_file</strong> <code class="def-code-arguments">(gnutls_srp_server_credentials_t <var class="var">res</var>, const char * <var class="var">password_file</var>, const char * <var class="var">password_conf_file</var>)</code><a class="copiable-link" href="#index-gnutls_005fsrp_005fset_005fserver_005fcredentials_005ffile-1"> &para;</a></span></dt>
<dd><p><var class="var">res</var>: is a <code class="code">gnutls_srp_server_credentials_t</code>  type.
</p>
<p><var class="var">password_file</var>: is the SRP password file (tpasswd)
</p>
<p><var class="var">password_conf_file</var>: is the SRP password conf file (tpasswd.conf)
</p>
<p>This function sets the password files, in a
<code class="code">gnutls_srp_server_credentials_t</code>  type.  Those password files
hold usernames and verifiers and will be used for SRP
authentication.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, or an
error code.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsrp_005fset_005fserver_005fcredentials_005ffunction-1"><span>gnutls_srp_set_server_credentials_function<a class="copiable-link" href="#gnutls_005fsrp_005fset_005fserver_005fcredentials_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsrp_005fset_005fserver_005fcredentials_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsrp_005fset_005fserver_005fcredentials_005ffunction-1"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_srp_set_server_credentials_function</strong> <code class="def-code-arguments">(gnutls_srp_server_credentials_t <var class="var">cred</var>, gnutls_srp_server_credentials_function * <var class="var">func</var>)</code><a class="copiable-link" href="#index-gnutls_005fsrp_005fset_005fserver_005fcredentials_005ffunction-1"> &para;</a></span></dt>
<dd><p><var class="var">cred</var>: is a <code class="code">gnutls_srp_server_credentials_t</code>  type.
</p>
<p><var class="var">func</var>: is the callback function
</p>
<p>This function can be used to set a callback to retrieve the user&rsquo;s
SRP credentials.  The callback&rsquo;s function form is:
</p>
<p>int (*callback)(gnutls_session_t, const char* username,
gnutls_datum_t *salt, gnutls_datum_t *verifier, gnutls_datum_t *generator,
gnutls_datum_t *prime);
</p>
<p><code class="code">username</code> contains the actual username.
The  <code class="code">salt</code> ,  <code class="code">verifier</code> ,  <code class="code">generator</code> and  <code class="code">prime</code> must be filled
in using the <code class="code">gnutls_malloc()</code> . For convenience  <code class="code">prime</code> and  <code class="code">generator</code> may also be one of the static parameters defined in gnutls.h.
</p>
<p>Initially, the data field is NULL in every <code class="code">gnutls_datum_t</code> 
structure that the callback has to fill in. When the
callback is done GnuTLS deallocates all of those buffers
which are non-NULL, regardless of the return value.
</p>
<p>In order to prevent attackers from guessing valid usernames,
if a user does not exist, g and n values should be filled in
using a random user&rsquo;s parameters. In that case the callback must
return the special value (1).
See <code class="code">gnutls_srp_set_server_fake_salt_seed</code>  too.
If this is not required for your application, return a negative
number from the callback to abort the handshake.
</p>
<p>The callback function will only be called once per handshake.
The callback function should return 0 on success, while
-1 indicates an error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsrp_005fset_005fserver_005ffake_005fsalt_005fseed-1"><span>gnutls_srp_set_server_fake_salt_seed<a class="copiable-link" href="#gnutls_005fsrp_005fset_005fserver_005ffake_005fsalt_005fseed-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsrp_005fset_005fserver_005ffake_005fsalt_005fseed"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsrp_005fset_005fserver_005ffake_005fsalt_005fseed"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_srp_set_server_fake_salt_seed</strong> <code class="def-code-arguments">(gnutls_srp_server_credentials_t <var class="var">cred</var>, const gnutls_datum_t * <var class="var">seed</var>, unsigned int <var class="var">salt_length</var>)</code><a class="copiable-link" href="#index-gnutls_005fsrp_005fset_005fserver_005ffake_005fsalt_005fseed"> &para;</a></span></dt>
<dd><p><var class="var">cred</var>: is a <code class="code">gnutls_srp_server_credentials_t</code>  type
</p>
<p><var class="var">seed</var>: is the seed data, only needs to be valid until the function
returns; size of the seed must be greater than zero
</p>
<p><var class="var">salt_length</var>: is the length of the generated fake salts
</p>
<p>This function sets the seed that is used to generate salts for
invalid (non-existent) usernames.
</p>
<p>In order to prevent attackers from guessing valid usernames,
when a user does not exist gnutls generates a salt and a verifier
and proceeds with the protocol as usual.
The authentication will ultimately fail, but the client cannot tell
whether the username is valid (exists) or invalid.
</p>
<p>If an attacker learns the seed, given a salt (which is part of the
handshake) which was generated when the seed was in use, it can tell
whether or not the authentication failed because of an unknown username.
This seed cannot be used to reveal application data or passwords.
</p>
<p><code class="code">salt_length</code> should represent the salt length your application uses.
Generating fake salts longer than 20 bytes is not supported.
</p>
<p>By default the seed is a random value, different each time a
<code class="code">gnutls_srp_server_credentials_t</code>  is allocated and fake salts are
16 bytes long.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsrp_005fverifier-1"><span>gnutls_srp_verifier<a class="copiable-link" href="#gnutls_005fsrp_005fverifier-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsrp_005fverifier"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsrp_005fverifier-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_srp_verifier</strong> <code class="def-code-arguments">(const char * <var class="var">username</var>, const char * <var class="var">password</var>, const gnutls_datum_t * <var class="var">salt</var>, const gnutls_datum_t * <var class="var">generator</var>, const gnutls_datum_t * <var class="var">prime</var>, gnutls_datum_t * <var class="var">res</var>)</code><a class="copiable-link" href="#index-gnutls_005fsrp_005fverifier-1"> &para;</a></span></dt>
<dd><p><var class="var">username</var>: is the user&rsquo;s name
</p>
<p><var class="var">password</var>: is the user&rsquo;s password
</p>
<p><var class="var">salt</var>: should be some randomly generated bytes
</p>
<p><var class="var">generator</var>: is the generator of the group
</p>
<p><var class="var">prime</var>: is the group&rsquo;s prime
</p>
<p><var class="var">res</var>: where the verifier will be stored.
</p>
<p>This function will create an SRP verifier, as specified in
RFC2945.  The  <code class="code">prime</code> and  <code class="code">generator</code> should be one of the static
parameters defined in gnutls/gnutls.h or may be generated.
</p>
<p>The verifier will be allocated with  <code class="code">gnutls_malloc</code> () and will be stored in
 <code class="code">res</code> using binary format.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, or an
error code.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsrtp_005fget_005fkeys-1"><span>gnutls_srtp_get_keys<a class="copiable-link" href="#gnutls_005fsrtp_005fget_005fkeys-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsrtp_005fget_005fkeys"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsrtp_005fget_005fkeys-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_srtp_get_keys</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, void * <var class="var">key_material</var>, unsigned int <var class="var">key_material_size</var>, gnutls_datum_t * <var class="var">client_key</var>, gnutls_datum_t * <var class="var">client_salt</var>, gnutls_datum_t * <var class="var">server_key</var>, gnutls_datum_t * <var class="var">server_salt</var>)</code><a class="copiable-link" href="#index-gnutls_005fsrtp_005fget_005fkeys-1"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">key_material</var>: Space to hold the generated key material
</p>
<p><var class="var">key_material_size</var>: The maximum size of the key material
</p>
<p><var class="var">client_key</var>: The master client write key, pointing inside the key material
</p>
<p><var class="var">client_salt</var>: The master client write salt, pointing inside the key material
</p>
<p><var class="var">server_key</var>: The master server write key, pointing inside the key material
</p>
<p><var class="var">server_salt</var>: The master server write salt, pointing inside the key material
</p>
<p>This is a helper function to generate the keying material for SRTP.
It requires the space of the key material to be pre-allocated (should be at least
2x the maximum key size and salt size). The  <code class="code">client_key</code> ,  <code class="code">client_salt</code> ,  <code class="code">server_key</code> and  <code class="code">server_salt</code> are convenience datums that point inside the key material. They may
be <code class="code">NULL</code> .
</p>
<p><strong class="strong">Returns:</strong> On success the size of the key material is returned,
otherwise, <code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  if the buffer given is not 
sufficient, or a negative error code.
</p>
<p>Since 3.1.4
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsrtp_005fget_005fmki-1"><span>gnutls_srtp_get_mki<a class="copiable-link" href="#gnutls_005fsrtp_005fget_005fmki-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsrtp_005fget_005fmki"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsrtp_005fget_005fmki"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_srtp_get_mki</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_datum_t * <var class="var">mki</var>)</code><a class="copiable-link" href="#index-gnutls_005fsrtp_005fget_005fmki"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">mki</var>: will hold the MKI
</p>
<p>This function exports the negotiated Master Key Identifier,
received by the peer if any. The returned value in  <code class="code">mki</code> should be 
treated as constant and valid only during the session&rsquo;s lifetime.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned.
</p>
<p>Since 3.1.4
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsrtp_005fget_005fprofile_005fid-1"><span>gnutls_srtp_get_profile_id<a class="copiable-link" href="#gnutls_005fsrtp_005fget_005fprofile_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsrtp_005fget_005fprofile_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsrtp_005fget_005fprofile_005fid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_srtp_get_profile_id</strong> <code class="def-code-arguments">(const char * <var class="var">name</var>, gnutls_srtp_profile_t * <var class="var">profile</var>)</code><a class="copiable-link" href="#index-gnutls_005fsrtp_005fget_005fprofile_005fid"> &para;</a></span></dt>
<dd><p><var class="var">name</var>: The name of the profile to look up
</p>
<p><var class="var">profile</var>: Will hold the profile id
</p>
<p>This function allows you to look up a profile based on a string.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned.
</p>
<p>Since 3.1.4
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsrtp_005fget_005fprofile_005fname-1"><span>gnutls_srtp_get_profile_name<a class="copiable-link" href="#gnutls_005fsrtp_005fget_005fprofile_005fname-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsrtp_005fget_005fprofile_005fname"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsrtp_005fget_005fprofile_005fname"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_srtp_get_profile_name</strong> <code class="def-code-arguments">(gnutls_srtp_profile_t <var class="var">profile</var>)</code><a class="copiable-link" href="#index-gnutls_005fsrtp_005fget_005fprofile_005fname"> &para;</a></span></dt>
<dd><p><var class="var">profile</var>: The profile to look up a string for
</p>
<p>This function allows you to get the corresponding name for a
SRTP protection profile.
</p>
<p><strong class="strong">Returns:</strong> On success, the name of a SRTP profile as a string,
otherwise NULL.
</p>
<p>Since 3.1.4
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsrtp_005fget_005fselected_005fprofile-1"><span>gnutls_srtp_get_selected_profile<a class="copiable-link" href="#gnutls_005fsrtp_005fget_005fselected_005fprofile-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsrtp_005fget_005fselected_005fprofile"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsrtp_005fget_005fselected_005fprofile"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_srtp_get_selected_profile</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_srtp_profile_t * <var class="var">profile</var>)</code><a class="copiable-link" href="#index-gnutls_005fsrtp_005fget_005fselected_005fprofile"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">profile</var>: will hold the profile
</p>
<p>This function allows you to get the negotiated SRTP profile.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned.
</p>
<p>Since 3.1.4
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsrtp_005fset_005fmki-1"><span>gnutls_srtp_set_mki<a class="copiable-link" href="#gnutls_005fsrtp_005fset_005fmki-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsrtp_005fset_005fmki"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsrtp_005fset_005fmki"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_srtp_set_mki</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, const gnutls_datum_t * <var class="var">mki</var>)</code><a class="copiable-link" href="#index-gnutls_005fsrtp_005fset_005fmki"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">mki</var>: holds the MKI
</p>
<p>This function sets the Master Key Identifier, to be
used by this session (if any).
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned.
</p>
<p>Since 3.1.4
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsrtp_005fset_005fprofile-1"><span>gnutls_srtp_set_profile<a class="copiable-link" href="#gnutls_005fsrtp_005fset_005fprofile-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsrtp_005fset_005fprofile"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsrtp_005fset_005fprofile"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_srtp_set_profile</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_srtp_profile_t <var class="var">profile</var>)</code><a class="copiable-link" href="#index-gnutls_005fsrtp_005fset_005fprofile"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">profile</var>: is the profile id to add.
</p>
<p>This function is to be used by both clients and servers, to declare
what SRTP profiles they support, to negotiate with the peer.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned.
</p>
<p>Since 3.1.4
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsrtp_005fset_005fprofile_005fdirect-1"><span>gnutls_srtp_set_profile_direct<a class="copiable-link" href="#gnutls_005fsrtp_005fset_005fprofile_005fdirect-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsrtp_005fset_005fprofile_005fdirect"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsrtp_005fset_005fprofile_005fdirect"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_srtp_set_profile_direct</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, const char * <var class="var">profiles</var>, const char ** <var class="var">err_pos</var>)</code><a class="copiable-link" href="#index-gnutls_005fsrtp_005fset_005fprofile_005fdirect"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">profiles</var>: is a string that contains the supported SRTP profiles,
separated by colons.
</p>
<p><var class="var">err_pos</var>: In case of an error this will have the position in the string the error occurred, may be NULL.
</p>
<p>This function is to be used by both clients and servers, to declare
what SRTP profiles they support, to negotiate with the peer.
</p>
<p><strong class="strong">Returns:</strong> On syntax error <code class="code">GNUTLS_E_INVALID_REQUEST</code>  is returned,
<code class="code">GNUTLS_E_SUCCESS</code>  on success, or an error code.
</p>
<p>Since 3.1.4
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fstore_005fcommitment-1"><span>gnutls_store_commitment<a class="copiable-link" href="#gnutls_005fstore_005fcommitment-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fstore_005fcommitment"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fstore_005fcommitment-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_store_commitment</strong> <code class="def-code-arguments">(const char * <var class="var">db_name</var>, gnutls_tdb_t <var class="var">tdb</var>, const char * <var class="var">host</var>, const char * <var class="var">service</var>, gnutls_digest_algorithm_t <var class="var">hash_algo</var>, const gnutls_datum_t * <var class="var">hash</var>, time_t <var class="var">expiration</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fstore_005fcommitment-1"> &para;</a></span></dt>
<dd><p><var class="var">db_name</var>: A file specifying the stored keys (use NULL for the default)
</p>
<p><var class="var">tdb</var>: A storage structure or NULL to use the default
</p>
<p><var class="var">host</var>: The peer&rsquo;s name
</p>
<p><var class="var">service</var>: non-NULL if this key is specific to a service (e.g. http)
</p>
<p><var class="var">hash_algo</var>: The hash algorithm type
</p>
<p><var class="var">hash</var>: The raw hash
</p>
<p><var class="var">expiration</var>: The expiration time (use 0 to disable expiration)
</p>
<p><var class="var">flags</var>: should be 0 or <code class="code">GNUTLS_SCOMMIT_FLAG_ALLOW_BROKEN</code> .
</p>
<p>This function will store the provided hash commitment to
the list of stored public keys. The key with the given
hash will be considered valid until the provided expiration time.
</p>
<p>The  <code class="code">tdb</code> variable if non-null specifies a custom backend for
the storage of entries. If it is NULL then the
default file backend will be used.
</p>
<p>Note that this function is not thread safe with the default backend.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fstore_005fpubkey-1"><span>gnutls_store_pubkey<a class="copiable-link" href="#gnutls_005fstore_005fpubkey-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fstore_005fpubkey"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fstore_005fpubkey-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_store_pubkey</strong> <code class="def-code-arguments">(const char * <var class="var">db_name</var>, gnutls_tdb_t <var class="var">tdb</var>, const char * <var class="var">host</var>, const char * <var class="var">service</var>, gnutls_certificate_type_t <var class="var">cert_type</var>, const gnutls_datum_t * <var class="var">cert</var>, time_t <var class="var">expiration</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fstore_005fpubkey-1"> &para;</a></span></dt>
<dd><p><var class="var">db_name</var>: A file specifying the stored keys (use NULL for the default)
</p>
<p><var class="var">tdb</var>: A storage structure or NULL to use the default
</p>
<p><var class="var">host</var>: The peer&rsquo;s name
</p>
<p><var class="var">service</var>: non-NULL if this key is specific to a service (e.g. http)
</p>
<p><var class="var">cert_type</var>: The type of the certificate
</p>
<p><var class="var">cert</var>: The data of the certificate
</p>
<p><var class="var">expiration</var>: The expiration time (use 0 to disable expiration)
</p>
<p><var class="var">flags</var>: should be 0.
</p>
<p>This function will store a raw public-key or a public-key provided via
a raw (DER-encoded) certificate to the list of stored public keys. The key
will be considered valid until the provided expiration time.
</p>
<p>The  <code class="code">tdb</code> variable if non-null specifies a custom backend for
the storage of entries. If it is NULL then the
default file backend will be used.
</p>
<p>Unless an alternative  <code class="code">tdb</code> is provided, the storage format is a textual format
consisting of a line for each host with fields separated by &rsquo;|&rsquo;. The contents of
the fields are a format-identifier which is set to &rsquo;g0&rsquo;, the hostname that the
rest of the data applies to, the numeric port or host name, the expiration
time in seconds since the epoch (0 for no expiration), and a base64
encoding of the raw (DER) public key information (SPKI) of the peer.
</p>
<p>As of GnuTLS 3.6.6 this function also accepts raw public keys.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.0.13
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fstrerror-1"><span>gnutls_strerror<a class="copiable-link" href="#gnutls_005fstrerror-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fstrerror"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fstrerror"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_strerror</strong> <code class="def-code-arguments">(int <var class="var">error</var>)</code><a class="copiable-link" href="#index-gnutls_005fstrerror"> &para;</a></span></dt>
<dd><p><var class="var">error</var>: is a GnuTLS error code, a negative error code
</p>
<p>This function is similar to strerror.  The difference is that it
accepts an error number returned by a gnutls function; In case of
an unknown error a descriptive string is sent instead of <code class="code">NULL</code> .
</p>
<p>Error codes are always a negative error code.
</p>
<p><strong class="strong">Returns:</strong> A string explaining the GnuTLS error message.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fstrerror_005fname-1"><span>gnutls_strerror_name<a class="copiable-link" href="#gnutls_005fstrerror_005fname-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fstrerror_005fname"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fstrerror_005fname"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_strerror_name</strong> <code class="def-code-arguments">(int <var class="var">error</var>)</code><a class="copiable-link" href="#index-gnutls_005fstrerror_005fname"> &para;</a></span></dt>
<dd><p><var class="var">error</var>: is an error returned by a gnutls function.
</p>
<p>Return the GnuTLS error code define as a string.  For example,
gnutls_strerror_name (GNUTLS_E_DH_PRIME_UNACCEPTABLE) will return
the string &quot;GNUTLS_E_DH_PRIME_UNACCEPTABLE&quot;.
</p>
<p><strong class="strong">Returns:</strong> A string corresponding to the symbol name of the error
code.
</p>
<p><strong class="strong">Since:</strong> 2.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsupplemental_005fget_005fname-1"><span>gnutls_supplemental_get_name<a class="copiable-link" href="#gnutls_005fsupplemental_005fget_005fname-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsupplemental_005fget_005fname"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsupplemental_005fget_005fname"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_supplemental_get_name</strong> <code class="def-code-arguments">(gnutls_supplemental_data_format_type_t <var class="var">type</var>)</code><a class="copiable-link" href="#index-gnutls_005fsupplemental_005fget_005fname"> &para;</a></span></dt>
<dd><p><var class="var">type</var>: is a supplemental data format type
</p>
<p>Convert a <code class="code">gnutls_supplemental_data_format_type_t</code>  value to a
string.
</p>
<p><strong class="strong">Returns:</strong> a string that contains the name of the specified
supplemental data format type, or <code class="code">NULL</code>  for unknown types.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsupplemental_005frecv-1"><span>gnutls_supplemental_recv<a class="copiable-link" href="#gnutls_005fsupplemental_005frecv-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsupplemental_005frecv"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsupplemental_005frecv"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_supplemental_recv</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, unsigned <var class="var">do_recv_supplemental</var>)</code><a class="copiable-link" href="#index-gnutls_005fsupplemental_005frecv"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">do_recv_supplemental</var>: non-zero in order to expect supplemental data
</p>
<p>This function is to be called by an extension handler to
instruct gnutls to attempt to receive supplemental data
during the handshake process.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsupplemental_005fregister-1"><span>gnutls_supplemental_register<a class="copiable-link" href="#gnutls_005fsupplemental_005fregister-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsupplemental_005fregister"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsupplemental_005fregister"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_supplemental_register</strong> <code class="def-code-arguments">(const char * <var class="var">name</var>, gnutls_supplemental_data_format_type_t <var class="var">type</var>, gnutls_supp_recv_func <var class="var">recv_func</var>, gnutls_supp_send_func <var class="var">send_func</var>)</code><a class="copiable-link" href="#index-gnutls_005fsupplemental_005fregister"> &para;</a></span></dt>
<dd><p><var class="var">name</var>: the name of the supplemental data to register
</p>
<p><var class="var">type</var>: the type of the supplemental data format
</p>
<p><var class="var">recv_func</var>: the function to receive the data
</p>
<p><var class="var">send_func</var>: the function to send the data
</p>
<p>This function will register a new supplemental data type (rfc4680).
The registered data will remain until <code class="code">gnutls_global_deinit()</code> 
is called. The provided  <code class="code">type</code> must be an unassigned type in
<code class="code">gnutls_supplemental_data_format_type_t</code> . If the type is already
registered or handled by GnuTLS internally <code class="code">GNUTLS_E_ALREADY_REGISTERED</code> 
will be returned.
</p>
<p>This function is not thread safe. As supplemental data are not defined under
TLS 1.3, this function will disable TLS 1.3 support globally.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsupplemental_005fsend-1"><span>gnutls_supplemental_send<a class="copiable-link" href="#gnutls_005fsupplemental_005fsend-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsupplemental_005fsend"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsupplemental_005fsend"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_supplemental_send</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, unsigned <var class="var">do_send_supplemental</var>)</code><a class="copiable-link" href="#index-gnutls_005fsupplemental_005fsend"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">do_send_supplemental</var>: non-zero in order to send supplemental data
</p>
<p>This function is to be called by an extension handler to
instruct gnutls to send supplemental data during the handshake process.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsystem_005frecv_005ftimeout-1"><span>gnutls_system_recv_timeout<a class="copiable-link" href="#gnutls_005fsystem_005frecv_005ftimeout-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsystem_005frecv_005ftimeout"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsystem_005frecv_005ftimeout"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_system_recv_timeout</strong> <code class="def-code-arguments">(gnutls_transport_ptr_t <var class="var">ptr</var>, unsigned int <var class="var">ms</var>)</code><a class="copiable-link" href="#index-gnutls_005fsystem_005frecv_005ftimeout"> &para;</a></span></dt>
<dd><p><var class="var">ptr</var>: A file descriptor (wrapped in a gnutls_transport_ptr_t pointer)
</p>
<p><var class="var">ms</var>: The number of milliseconds to wait.
</p>
<p>Wait for data to be received from the provided socket ( <code class="code">ptr</code> ) within a
timeout period in milliseconds, using <code class="code">select()</code>  on the provided  <code class="code">ptr</code> .
</p>
<p>This function is provided as a helper for constructing custom
callbacks for <code class="code">gnutls_transport_set_pull_timeout_function()</code> ,
which can be used if you rely on socket file descriptors.
</p>
<p>Returns -1 on error, 0 on timeout, positive value if data are available for reading.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005ftdb_005fdeinit-1"><span>gnutls_tdb_deinit<a class="copiable-link" href="#gnutls_005ftdb_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005ftdb_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ftdb_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_tdb_deinit</strong> <code class="def-code-arguments">(gnutls_tdb_t <var class="var">tdb</var>)</code><a class="copiable-link" href="#index-gnutls_005ftdb_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">tdb</var>: The structure to be deinitialized
</p>
<p>This function will deinitialize a public key trust storage structure.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005ftdb_005finit-1"><span>gnutls_tdb_init<a class="copiable-link" href="#gnutls_005ftdb_005finit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005ftdb_005finit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ftdb_005finit"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_tdb_init</strong> <code class="def-code-arguments">(gnutls_tdb_t * <var class="var">tdb</var>)</code><a class="copiable-link" href="#index-gnutls_005ftdb_005finit"> &para;</a></span></dt>
<dd><p><var class="var">tdb</var>: A pointer to the type to be initialized
</p>
<p>This function will initialize a public key trust storage structure.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005ftdb_005fset_005fstore_005fcommitment_005ffunc-1"><span>gnutls_tdb_set_store_commitment_func<a class="copiable-link" href="#gnutls_005ftdb_005fset_005fstore_005fcommitment_005ffunc-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005ftdb_005fset_005fstore_005fcommitment_005ffunc"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ftdb_005fset_005fstore_005fcommitment_005ffunc"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_tdb_set_store_commitment_func</strong> <code class="def-code-arguments">(gnutls_tdb_t <var class="var">tdb</var>, gnutls_tdb_store_commitment_func <var class="var">cstore</var>)</code><a class="copiable-link" href="#index-gnutls_005ftdb_005fset_005fstore_005fcommitment_005ffunc"> &para;</a></span></dt>
<dd><p><var class="var">tdb</var>: The trust storage
</p>
<p><var class="var">cstore</var>: The commitment storage function
</p>
<p>This function will associate a commitment (hash) storage function with the
trust storage structure. The function is of the following form.
</p>
<p>int gnutls_tdb_store_commitment_func(const char* db_name, const char* host,
const char* service, time_t expiration,
gnutls_digest_algorithm_t, const gnutls_datum_t* hash);
</p>
<p>The  <code class="code">db_name</code> should be used to pass any private data to this function.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005ftdb_005fset_005fstore_005ffunc-1"><span>gnutls_tdb_set_store_func<a class="copiable-link" href="#gnutls_005ftdb_005fset_005fstore_005ffunc-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005ftdb_005fset_005fstore_005ffunc"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ftdb_005fset_005fstore_005ffunc"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_tdb_set_store_func</strong> <code class="def-code-arguments">(gnutls_tdb_t <var class="var">tdb</var>, gnutls_tdb_store_func <var class="var">store</var>)</code><a class="copiable-link" href="#index-gnutls_005ftdb_005fset_005fstore_005ffunc"> &para;</a></span></dt>
<dd><p><var class="var">tdb</var>: The trust storage
</p>
<p><var class="var">store</var>: The storage function
</p>
<p>This function will associate a storage function with the
trust storage structure. The function is of the following form.
</p>
<p>int gnutls_tdb_store_func(const char* db_name, const char* host,
const char* service, time_t expiration,
const gnutls_datum_t* pubkey);
</p>
<p>The  <code class="code">db_name</code> should be used to pass any private data to this function.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005ftdb_005fset_005fverify_005ffunc-1"><span>gnutls_tdb_set_verify_func<a class="copiable-link" href="#gnutls_005ftdb_005fset_005fverify_005ffunc-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005ftdb_005fset_005fverify_005ffunc"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ftdb_005fset_005fverify_005ffunc"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_tdb_set_verify_func</strong> <code class="def-code-arguments">(gnutls_tdb_t <var class="var">tdb</var>, gnutls_tdb_verify_func <var class="var">verify</var>)</code><a class="copiable-link" href="#index-gnutls_005ftdb_005fset_005fverify_005ffunc"> &para;</a></span></dt>
<dd><p><var class="var">tdb</var>: The trust storage
</p>
<p><var class="var">verify</var>: The verification function
</p>
<p>This function will associate a retrieval function with the
trust storage structure. The function is of the following form.
</p>
<p>int gnutls_tdb_verify_func(const char* db_name, const char* host,
const char* service, const gnutls_datum_t* pubkey);
</p>
<p>The verify function should return zero on a match, <code class="code">GNUTLS_E_CERTIFICATE_KEY_MISMATCH</code> 
if there is a mismatch and any other negative error code otherwise.
</p>
<p>The  <code class="code">db_name</code> should be used to pass any private data to this function.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005ftransport_005fget_005fint-1"><span>gnutls_transport_get_int<a class="copiable-link" href="#gnutls_005ftransport_005fget_005fint-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005ftransport_005fget_005fint"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ftransport_005fget_005fint"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_transport_get_int</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005ftransport_005fget_005fint"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>Used to get the first argument of the transport function (like
PUSH and PULL).  This must have been set using
<code class="code">gnutls_transport_set_int()</code> .
</p>
<p><strong class="strong">Returns:</strong> The first argument of the transport function.
</p>
<p><strong class="strong">Since:</strong> 3.1.9
</p></dd></dl>

<h4 class="subheading" id="gnutls_005ftransport_005fget_005fint2-1"><span>gnutls_transport_get_int2<a class="copiable-link" href="#gnutls_005ftransport_005fget_005fint2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005ftransport_005fget_005fint2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ftransport_005fget_005fint2"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_transport_get_int2</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, int * <var class="var">recv_int</var>, int * <var class="var">send_int</var>)</code><a class="copiable-link" href="#index-gnutls_005ftransport_005fget_005fint2"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">recv_int</var>: will hold the value for the pull function
</p>
<p><var class="var">send_int</var>: will hold the value for the push function
</p>
<p>Used to get the arguments of the transport functions (like PUSH
and PULL).  These should have been set using
<code class="code">gnutls_transport_set_int2()</code> .
</p>
<p><strong class="strong">Since:</strong> 3.1.9
</p></dd></dl>

<h4 class="subheading" id="gnutls_005ftransport_005fget_005fptr-1"><span>gnutls_transport_get_ptr<a class="copiable-link" href="#gnutls_005ftransport_005fget_005fptr-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005ftransport_005fget_005fptr"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ftransport_005fget_005fptr"><span class="category-def">Function: </span><span><code class="def-type">gnutls_transport_ptr_t</code> <strong class="def-name">gnutls_transport_get_ptr</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005ftransport_005fget_005fptr"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>Used to get the first argument of the transport function (like
PUSH and PULL).  This must have been set using
<code class="code">gnutls_transport_set_ptr()</code> .
</p>
<p><strong class="strong">Returns:</strong> The first argument of the transport function.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005ftransport_005fget_005fptr2-1"><span>gnutls_transport_get_ptr2<a class="copiable-link" href="#gnutls_005ftransport_005fget_005fptr2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005ftransport_005fget_005fptr2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ftransport_005fget_005fptr2"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_transport_get_ptr2</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_transport_ptr_t * <var class="var">recv_ptr</var>, gnutls_transport_ptr_t * <var class="var">send_ptr</var>)</code><a class="copiable-link" href="#index-gnutls_005ftransport_005fget_005fptr2"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">recv_ptr</var>: will hold the value for the pull function
</p>
<p><var class="var">send_ptr</var>: will hold the value for the push function
</p>
<p>Used to get the arguments of the transport functions (like PUSH
and PULL).  These should have been set using
<code class="code">gnutls_transport_set_ptr2()</code> .
</p></dd></dl>

<h4 class="subheading" id="gnutls_005ftransport_005fis_005fktls_005fenabled-1"><span>gnutls_transport_is_ktls_enabled<a class="copiable-link" href="#gnutls_005ftransport_005fis_005fktls_005fenabled-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005ftransport_005fis_005fktls_005fenabled"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ftransport_005fis_005fktls_005fenabled"><span class="category-def">Function: </span><span><code class="def-type">gnutls_transport_ktls_enable_flags_t</code> <strong class="def-name">gnutls_transport_is_ktls_enabled</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005ftransport_005fis_005fktls_005fenabled"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>Checks if KTLS is now enabled and was properly inicialized.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_KTLS_RECV</code> , <code class="code">GNUTLS_KTLS_SEND</code> , <code class="code">GNUTLS_KTLS_DUPLEX</code> , otherwise 0
</p>
<p><strong class="strong">Since:</strong> 3.7.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005ftransport_005fset_005ferrno-1"><span>gnutls_transport_set_errno<a class="copiable-link" href="#gnutls_005ftransport_005fset_005ferrno-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005ftransport_005fset_005ferrno"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ftransport_005fset_005ferrno-1"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_transport_set_errno</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, int <var class="var">err</var>)</code><a class="copiable-link" href="#index-gnutls_005ftransport_005fset_005ferrno-1"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">err</var>: error value to store in session-specific errno variable.
</p>
<p>Store  <code class="code">err</code> in the session-specific errno variable.  Useful values
for  <code class="code">err</code> are EINTR, EAGAIN and EMSGSIZE, other values are treated will be
treated as real errors in the push/pull function.
</p>
<p>This function is useful in replacement push and pull functions set by
<code class="code">gnutls_transport_set_push_function()</code>  and
<code class="code">gnutls_transport_set_pull_function()</code>  under Windows, where the
replacements may not have access to the same  <code class="code">errno</code> variable that is used by GnuTLS (e.g., the application is linked to
msvcr71.dll and gnutls is linked to msvcrt.dll).
</p>
<p>This function is unreliable if you are using the same
 <code class="code">session</code> in different threads for sending and receiving.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005ftransport_005fset_005ferrno_005ffunction-1"><span>gnutls_transport_set_errno_function<a class="copiable-link" href="#gnutls_005ftransport_005fset_005ferrno_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005ftransport_005fset_005ferrno_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ftransport_005fset_005ferrno_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_transport_set_errno_function</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_errno_func <var class="var">errno_func</var>)</code><a class="copiable-link" href="#index-gnutls_005ftransport_005fset_005ferrno_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">errno_func</var>: a callback function similar to <code class="code">write()</code> 
</p>
<p>This is the function where you set a function to retrieve errno
after a failed push or pull operation.
</p>
<p><code class="code">errno_func</code> is of the form,
int (*gnutls_errno_func)(gnutls_transport_ptr_t);
and should return the errno.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005ftransport_005fset_005fint-1"><span>gnutls_transport_set_int<a class="copiable-link" href="#gnutls_005ftransport_005fset_005fint-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005ftransport_005fset_005fint"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ftransport_005fset_005fint"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_transport_set_int</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, int <var class="var">fd</var>)</code><a class="copiable-link" href="#index-gnutls_005ftransport_005fset_005fint"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">fd</var>: is the socket descriptor for the connection.
</p>
<p>This function sets the first argument of the transport function, such
as <code class="code">send()</code>  and <code class="code">recv()</code>  for the default callbacks using the
system&rsquo;s socket API.
</p>
<p>This function is equivalent to calling <code class="code">gnutls_transport_set_ptr()</code> 
with the descriptor, but requires no casts.
</p>
<p><strong class="strong">Since:</strong> 3.1.9
</p></dd></dl>

<h4 class="subheading" id="gnutls_005ftransport_005fset_005fint2-1"><span>gnutls_transport_set_int2<a class="copiable-link" href="#gnutls_005ftransport_005fset_005fint2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005ftransport_005fset_005fint2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ftransport_005fset_005fint2"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_transport_set_int2</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, int <var class="var">recv_fd</var>, int <var class="var">send_fd</var>)</code><a class="copiable-link" href="#index-gnutls_005ftransport_005fset_005fint2"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">recv_fd</var>: is socket descriptor for the pull function
</p>
<p><var class="var">send_fd</var>: is socket descriptor for the push function
</p>
<p>This function sets the first argument of the transport functions,
such as <code class="code">send()</code>  and <code class="code">recv()</code>  for the default callbacks using the
system&rsquo;s socket API. With this function you can set two different
descriptors for receiving and sending.
</p>
<p>This function is equivalent to calling <code class="code">gnutls_transport_set_ptr2()</code> 
with the descriptors, but requires no casts.
</p>
<p><strong class="strong">Since:</strong> 3.1.9
</p></dd></dl>

<h4 class="subheading" id="gnutls_005ftransport_005fset_005fptr-1"><span>gnutls_transport_set_ptr<a class="copiable-link" href="#gnutls_005ftransport_005fset_005fptr-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005ftransport_005fset_005fptr"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ftransport_005fset_005fptr"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_transport_set_ptr</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_transport_ptr_t <var class="var">ptr</var>)</code><a class="copiable-link" href="#index-gnutls_005ftransport_005fset_005fptr"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">ptr</var>: is the value.
</p>
<p>Used to set the first argument of the transport function (for push
and pull callbacks). In berkeley style sockets this function will set the
connection descriptor.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005ftransport_005fset_005fptr2-1"><span>gnutls_transport_set_ptr2<a class="copiable-link" href="#gnutls_005ftransport_005fset_005fptr2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005ftransport_005fset_005fptr2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ftransport_005fset_005fptr2"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_transport_set_ptr2</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_transport_ptr_t <var class="var">recv_ptr</var>, gnutls_transport_ptr_t <var class="var">send_ptr</var>)</code><a class="copiable-link" href="#index-gnutls_005ftransport_005fset_005fptr2"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">recv_ptr</var>: is the value for the pull function
</p>
<p><var class="var">send_ptr</var>: is the value for the push function
</p>
<p>Used to set the first argument of the transport function (for push
and pull callbacks). In berkeley style sockets this function will set the
connection descriptor.  With this function you can use two different
pointers for receiving and sending.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005ftransport_005fset_005fpull_005ffunction-1"><span>gnutls_transport_set_pull_function<a class="copiable-link" href="#gnutls_005ftransport_005fset_005fpull_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005ftransport_005fset_005fpull_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ftransport_005fset_005fpull_005ffunction-1"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_transport_set_pull_function</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_pull_func <var class="var">pull_func</var>)</code><a class="copiable-link" href="#index-gnutls_005ftransport_005fset_005fpull_005ffunction-1"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">pull_func</var>: a callback function similar to <code class="code">read()</code> 
</p>
<p>This is the function where you set a function for gnutls to receive
data.  Normally, if you use berkeley style sockets, do not need to
use this function since the default recv(2) will probably be ok.
The callback should return 0 on connection termination, a positive
number indicating the number of bytes received, and -1 on error.
</p>
<p><code class="code">gnutls_pull_func</code> is of the form,
ssize_t (*gnutls_pull_func)(gnutls_transport_ptr_t, void*, size_t);
</p></dd></dl>

<h4 class="subheading" id="gnutls_005ftransport_005fset_005fpull_005ftimeout_005ffunction-1"><span>gnutls_transport_set_pull_timeout_function<a class="copiable-link" href="#gnutls_005ftransport_005fset_005fpull_005ftimeout_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005ftransport_005fset_005fpull_005ftimeout_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ftransport_005fset_005fpull_005ftimeout_005ffunction-2"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_transport_set_pull_timeout_function</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_pull_timeout_func <var class="var">func</var>)</code><a class="copiable-link" href="#index-gnutls_005ftransport_005fset_005fpull_005ftimeout_005ffunction-2"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">func</var>: a callback function
</p>
<p>This is the function where you set a function for gnutls to know
whether data are ready to be received. It should wait for data a
given time frame in milliseconds. The callback should return 0 on 
timeout, a positive number if data can be received, and -1 on error.
You&rsquo;ll need to override this function if <code class="code">select()</code>  is not suitable
for the provided transport calls.
</p>
<p>As with <code class="code">select()</code> , if the timeout value is zero the callback should return
zero if no data are immediately available. The special value
<code class="code">GNUTLS_INDEFINITE_TIMEOUT</code>  indicates that the callback should wait indefinitely
for data.
</p>
<p><code class="code">gnutls_pull_timeout_func</code> is of the form,
int (*gnutls_pull_timeout_func)(gnutls_transport_ptr_t, unsigned int ms);
</p>
<p>This callback is necessary when <code class="code">gnutls_handshake_set_timeout()</code>  or 
<code class="code">gnutls_record_set_timeout()</code>  are set, under TLS1.3 and for enforcing the DTLS
mode timeouts when in blocking mode.
</p>
<p>For compatibility with future GnuTLS versions this callback must be set when
a custom pull function is registered. The callback will not be used when the
session is in TLS mode with non-blocking sockets. That is, when <code class="code">GNUTLS_NONBLOCK</code> 
is specified for a TLS session in <code class="code">gnutls_init()</code> .
</p>
<p>The helper function <code class="code">gnutls_system_recv_timeout()</code>  is provided to
simplify writing callbacks. 
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005ftransport_005fset_005fpush_005ffunction-1"><span>gnutls_transport_set_push_function<a class="copiable-link" href="#gnutls_005ftransport_005fset_005fpush_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005ftransport_005fset_005fpush_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ftransport_005fset_005fpush_005ffunction-1"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_transport_set_push_function</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_push_func <var class="var">push_func</var>)</code><a class="copiable-link" href="#index-gnutls_005ftransport_005fset_005fpush_005ffunction-1"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">push_func</var>: a callback function similar to <code class="code">write()</code> 
</p>
<p>This is the function where you set a push function for gnutls to
use in order to send data.  If you are going to use berkeley style
sockets, you do not need to use this function since the default
send(2) will probably be ok.  Otherwise you should specify this
function for gnutls to be able to send data.
The callback should return a positive number indicating the
bytes sent, and -1 on error.
</p>
<p><code class="code">push_func</code> is of the form,
ssize_t (*gnutls_push_func)(gnutls_transport_ptr_t, const void*, size_t);
</p></dd></dl>

<h4 class="subheading" id="gnutls_005ftransport_005fset_005fvec_005fpush_005ffunction-1"><span>gnutls_transport_set_vec_push_function<a class="copiable-link" href="#gnutls_005ftransport_005fset_005fvec_005fpush_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005ftransport_005fset_005fvec_005fpush_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ftransport_005fset_005fvec_005fpush_005ffunction-1"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_transport_set_vec_push_function</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_vec_push_func <var class="var">vec_func</var>)</code><a class="copiable-link" href="#index-gnutls_005ftransport_005fset_005fvec_005fpush_005ffunction-1"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">vec_func</var>: a callback function similar to <code class="code">writev()</code> 
</p>
<p>Using this function you can override the default writev(2)
function for gnutls to send data. Setting this callback 
instead of <code class="code">gnutls_transport_set_push_function()</code>  is recommended
since it introduces less overhead in the TLS handshake process.
</p>
<p><code class="code">vec_func</code> is of the form,
ssize_t (*gnutls_vec_push_func) (gnutls_transport_ptr_t, const giovec_t * iov, int iovcnt);
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005furl_005fis_005fsupported-1"><span>gnutls_url_is_supported<a class="copiable-link" href="#gnutls_005furl_005fis_005fsupported-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005furl_005fis_005fsupported"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005furl_005fis_005fsupported-1"><span class="category-def">Function: </span><span><code class="def-type">unsigned</code> <strong class="def-name">gnutls_url_is_supported</strong> <code class="def-code-arguments">(const char * <var class="var">url</var>)</code><a class="copiable-link" href="#index-gnutls_005furl_005fis_005fsupported-1"> &para;</a></span></dt>
<dd><p><var class="var">url</var>: A URI to be tested
</p>
<p>Check whether the provided  <code class="code">url</code> is supported.  Depending on the system libraries
GnuTLS may support pkcs11, tpmkey or other URLs.
</p>
<p><strong class="strong">Returns:</strong> return non-zero if the given URL is supported, and zero if
it is not known.
</p>
<p><strong class="strong">Since:</strong> 3.1.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005futf8_005fpassword_005fnormalize-1"><span>gnutls_utf8_password_normalize<a class="copiable-link" href="#gnutls_005futf8_005fpassword_005fnormalize-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005futf8_005fpassword_005fnormalize"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005futf8_005fpassword_005fnormalize"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_utf8_password_normalize</strong> <code class="def-code-arguments">(const unsigned char * <var class="var">password</var>, unsigned <var class="var">plen</var>, gnutls_datum_t * <var class="var">out</var>, unsigned <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005futf8_005fpassword_005fnormalize"> &para;</a></span></dt>
<dd><p><var class="var">password</var>: contain the UTF-8 formatted password
</p>
<p><var class="var">plen</var>: the length of the provided password
</p>
<p><var class="var">out</var>: the result in an null-terminated allocated string
</p>
<p><var class="var">flags</var>: should be zero
</p>
<p>This function will convert the provided UTF-8 password according
to the normalization rules in RFC7613.
</p>
<p>If the flag <code class="code">GNUTLS_UTF8_IGNORE_ERRS</code>  is specified, any UTF-8 encoding
errors will be ignored, and in that case the output will be a copy of the input.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_INVALID_UTF8_STRING</code>  on invalid UTF-8 data, or 0 on success.
</p>
<p><strong class="strong">Since:</strong> 3.5.7
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fverify_005fstored_005fpubkey-1"><span>gnutls_verify_stored_pubkey<a class="copiable-link" href="#gnutls_005fverify_005fstored_005fpubkey-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fverify_005fstored_005fpubkey"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fverify_005fstored_005fpubkey-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_verify_stored_pubkey</strong> <code class="def-code-arguments">(const char * <var class="var">db_name</var>, gnutls_tdb_t <var class="var">tdb</var>, const char * <var class="var">host</var>, const char * <var class="var">service</var>, gnutls_certificate_type_t <var class="var">cert_type</var>, const gnutls_datum_t * <var class="var">cert</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fverify_005fstored_005fpubkey-1"> &para;</a></span></dt>
<dd><p><var class="var">db_name</var>: A file specifying the stored keys (use NULL for the default)
</p>
<p><var class="var">tdb</var>: A storage structure or NULL to use the default
</p>
<p><var class="var">host</var>: The peer&rsquo;s name
</p>
<p><var class="var">service</var>: non-NULL if this key is specific to a service (e.g. http)
</p>
<p><var class="var">cert_type</var>: The type of the certificate
</p>
<p><var class="var">cert</var>: The raw (der) data of the certificate
</p>
<p><var class="var">flags</var>: should be 0.
</p>
<p>This function will try to verify a raw public-key or a public-key provided via
a raw (DER-encoded) certificate using a list of stored public keys.
The  <code class="code">service</code> field if non-NULL should be a port number.
</p>
<p>The  <code class="code">db_name</code> variable if non-null specifies a custom backend for
the retrieval of entries. If it is NULL then the
default file backend will be used. In POSIX-like systems the
file backend uses the $HOME/.gnutls/known_hosts file.
</p>
<p>Note that if the custom storage backend is provided the
retrieval function should return <code class="code">GNUTLS_E_CERTIFICATE_KEY_MISMATCH</code> 
if the host/service pair is found but key doesn&rsquo;t match,
<code class="code">GNUTLS_E_NO_CERTIFICATE_FOUND</code>  if no such host/service with
the given key is found, and 0 if it was found. The storage
function should return 0 on success.
</p>
<p>As of GnuTLS 3.6.6 this function also verifies raw public keys.
</p>
<p><strong class="strong">Returns:</strong> If no associated public key is found
then <code class="code">GNUTLS_E_NO_CERTIFICATE_FOUND</code>  will be returned. If a key
is found but does not match <code class="code">GNUTLS_E_CERTIFICATE_KEY_MISMATCH</code> 
is returned. On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
or a negative error value on other errors.
</p>
<p><strong class="strong">Since:</strong> 3.0.13
</p></dd></dl>


<hr>
</div>
<div class="section-level-extent" id="Datagram-TLS-API">
<div class="nav-panel">
<p>
Next: <a href="#X509-certificate-API" accesskey="n" rel="next"><abbr class="acronym">X.509</abbr> certificate API</a>, Previous: <a href="#Core-TLS-API" accesskey="p" rel="prev">Core TLS API</a>, Up: <a href="#API-reference" accesskey="u" rel="up">API reference</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Datagram-TLS-API-1"><span>E.2 Datagram TLS API<a class="copiable-link" href="#Datagram-TLS-API-1"> &para;</a></span></h3>

<p>The prototypes for the following functions lie in
<samp class="file">gnutls/dtls.h</samp>.
</p>

<h4 class="subheading" id="gnutls_005fdtls_005fcookie_005fsend-1"><span>gnutls_dtls_cookie_send<a class="copiable-link" href="#gnutls_005fdtls_005fcookie_005fsend-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdtls_005fcookie_005fsend"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdtls_005fcookie_005fsend"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_dtls_cookie_send</strong> <code class="def-code-arguments">(gnutls_datum_t * <var class="var">key</var>, void * <var class="var">client_data</var>, size_t <var class="var">client_data_size</var>, gnutls_dtls_prestate_st * <var class="var">prestate</var>, gnutls_transport_ptr_t <var class="var">ptr</var>, gnutls_push_func <var class="var">push_func</var>)</code><a class="copiable-link" href="#index-gnutls_005fdtls_005fcookie_005fsend"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: is a random key to be used at cookie generation
</p>
<p><var class="var">client_data</var>: contains data identifying the client (i.e. address)
</p>
<p><var class="var">client_data_size</var>: The size of client&rsquo;s data
</p>
<p><var class="var">prestate</var>: The previous cookie returned by <code class="code">gnutls_dtls_cookie_verify()</code> 
</p>
<p><var class="var">ptr</var>: A transport pointer to be used by  <code class="code">push_func</code> 
</p>
<p><var class="var">push_func</var>: A function that will be used to reply
</p>
<p>This function can be used to prevent denial of service
attacks to a DTLS server by requiring the client to
reply using a cookie sent by this function. That way
it can be ensured that a client we allocated resources
for (i.e. <code class="code">gnutls_session_t</code> ) is the one that the 
original incoming packet was originated from.
</p>
<p>This function must be called at the first incoming packet,
prior to allocating any resources and must be succeeded
by <code class="code">gnutls_dtls_cookie_verify()</code> .
</p>
<p><strong class="strong">Returns:</strong> the number of bytes sent, or a negative error code.  
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdtls_005fcookie_005fverify-1"><span>gnutls_dtls_cookie_verify<a class="copiable-link" href="#gnutls_005fdtls_005fcookie_005fverify-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdtls_005fcookie_005fverify"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdtls_005fcookie_005fverify"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_dtls_cookie_verify</strong> <code class="def-code-arguments">(gnutls_datum_t * <var class="var">key</var>, void * <var class="var">client_data</var>, size_t <var class="var">client_data_size</var>, void * <var class="var">_msg</var>, size_t <var class="var">msg_size</var>, gnutls_dtls_prestate_st * <var class="var">prestate</var>)</code><a class="copiable-link" href="#index-gnutls_005fdtls_005fcookie_005fverify"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: is a random key to be used at cookie generation
</p>
<p><var class="var">client_data</var>: contains data identifying the client (i.e. address)
</p>
<p><var class="var">client_data_size</var>: The size of client&rsquo;s data
</p>
<p><var class="var">_msg</var>: An incoming message that initiates a connection.
</p>
<p><var class="var">msg_size</var>: The size of the message.
</p>
<p><var class="var">prestate</var>: The cookie of this client.
</p>
<p>This function will verify the received message for
a valid cookie. If a valid cookie is returned then
it should be associated with the session using
<code class="code">gnutls_dtls_prestate_set()</code> ;
</p>
<p>This function must be called after <code class="code">gnutls_dtls_cookie_send()</code> .
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  (0) on success, or a negative error code.  
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdtls_005fget_005fdata_005fmtu-1"><span>gnutls_dtls_get_data_mtu<a class="copiable-link" href="#gnutls_005fdtls_005fget_005fdata_005fmtu-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdtls_005fget_005fdata_005fmtu"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdtls_005fget_005fdata_005fmtu"><span class="category-def">Function: </span><span><code class="def-type">unsigned int</code> <strong class="def-name">gnutls_dtls_get_data_mtu</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fdtls_005fget_005fdata_005fmtu"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>This function will return the actual maximum transfer unit for
application data. I.e. DTLS headers are subtracted from the
actual MTU which is set using <code class="code">gnutls_dtls_set_mtu()</code> .
</p>
<p><strong class="strong">Returns:</strong> the maximum allowed transfer unit.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdtls_005fget_005fmtu-1"><span>gnutls_dtls_get_mtu<a class="copiable-link" href="#gnutls_005fdtls_005fget_005fmtu-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdtls_005fget_005fmtu"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdtls_005fget_005fmtu"><span class="category-def">Function: </span><span><code class="def-type">unsigned int</code> <strong class="def-name">gnutls_dtls_get_mtu</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fdtls_005fget_005fmtu"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>This function will return the MTU size as set with
<code class="code">gnutls_dtls_set_mtu()</code> . This is not the actual MTU
of data you can transmit. Use <code class="code">gnutls_dtls_get_data_mtu()</code> 
for that reason.
</p>
<p><strong class="strong">Returns:</strong> the set maximum transfer unit.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdtls_005fget_005ftimeout-1"><span>gnutls_dtls_get_timeout<a class="copiable-link" href="#gnutls_005fdtls_005fget_005ftimeout-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdtls_005fget_005ftimeout"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdtls_005fget_005ftimeout-1"><span class="category-def">Function: </span><span><code class="def-type">unsigned int</code> <strong class="def-name">gnutls_dtls_get_timeout</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fdtls_005fget_005ftimeout-1"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>This function will return the milliseconds remaining
for a retransmission of the previously sent handshake
message. This function is useful when DTLS is used in
non-blocking mode, to estimate when to call <code class="code">gnutls_handshake()</code> 
if no packets have been received.
</p>
<p><strong class="strong">Returns:</strong> the remaining time in milliseconds.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdtls_005fprestate_005fset-1"><span>gnutls_dtls_prestate_set<a class="copiable-link" href="#gnutls_005fdtls_005fprestate_005fset-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdtls_005fprestate_005fset"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdtls_005fprestate_005fset"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_dtls_prestate_set</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_dtls_prestate_st * <var class="var">prestate</var>)</code><a class="copiable-link" href="#index-gnutls_005fdtls_005fprestate_005fset"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: a new session
</p>
<p><var class="var">prestate</var>: contains the client&rsquo;s prestate
</p>
<p>This function will associate the prestate acquired by
the cookie authentication with the client, with the newly 
established session.
</p>
<p>This functions must be called after a successful <code class="code">gnutls_dtls_cookie_verify()</code> 
and should be succeeded by the actual DTLS handshake using <code class="code">gnutls_handshake()</code> .
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdtls_005fset_005fdata_005fmtu-1"><span>gnutls_dtls_set_data_mtu<a class="copiable-link" href="#gnutls_005fdtls_005fset_005fdata_005fmtu-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdtls_005fset_005fdata_005fmtu"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdtls_005fset_005fdata_005fmtu"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_dtls_set_data_mtu</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, unsigned int <var class="var">mtu</var>)</code><a class="copiable-link" href="#index-gnutls_005fdtls_005fset_005fdata_005fmtu"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">mtu</var>: The maximum unencrypted transfer unit of the session
</p>
<p>This function will set the maximum size of the *unencrypted* records
which will be sent over a DTLS session. It is equivalent to calculating
the DTLS packet overhead with the current encryption parameters, and
calling <code class="code">gnutls_dtls_set_mtu()</code>  with that value. In particular, this means
that you may need to call this function again after any negotiation or
renegotiation, in order to ensure that the MTU is still sufficient to
account for the new protocol overhead.
</p>
<p>In most cases you only need to call <code class="code">gnutls_dtls_set_mtu()</code>  with
the maximum MTU of your transport layer.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  (0) on success, or a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.1
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdtls_005fset_005fmtu-1"><span>gnutls_dtls_set_mtu<a class="copiable-link" href="#gnutls_005fdtls_005fset_005fmtu-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdtls_005fset_005fmtu"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdtls_005fset_005fmtu"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_dtls_set_mtu</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, unsigned int <var class="var">mtu</var>)</code><a class="copiable-link" href="#index-gnutls_005fdtls_005fset_005fmtu"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">mtu</var>: The maximum transfer unit of the transport
</p>
<p>This function will set the maximum transfer unit of the transport
that DTLS packets are sent over. Note that this should exclude
the IP (or IPv6) and UDP headers. So for DTLS over IPv6 on an
Ethernet device with MTU 1500, the DTLS MTU set with this function
would be 1500 - 40 (IPV6 header) - 8 (UDP header) = 1452.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdtls_005fset_005ftimeouts-1"><span>gnutls_dtls_set_timeouts<a class="copiable-link" href="#gnutls_005fdtls_005fset_005ftimeouts-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdtls_005fset_005ftimeouts"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdtls_005fset_005ftimeouts"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_dtls_set_timeouts</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, unsigned int <var class="var">retrans_timeout</var>, unsigned int <var class="var">total_timeout</var>)</code><a class="copiable-link" href="#index-gnutls_005fdtls_005fset_005ftimeouts"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">retrans_timeout</var>: The time at which a retransmission will occur in milliseconds
</p>
<p><var class="var">total_timeout</var>: The time at which the connection will be aborted, in milliseconds.
</p>
<p>This function will set the timeouts required for the DTLS handshake
protocol. The retransmission timeout is the time after which a
message from the peer is not received, the previous messages will
be retransmitted. The total timeout is the time after which the
handshake will be aborted with <code class="code">GNUTLS_E_TIMEDOUT</code> .
</p>
<p>The DTLS protocol recommends the values of 1 sec and 60 seconds
respectively, and these are the default values.
</p>
<p>To disable retransmissions set a  <code class="code">retrans_timeout</code> larger than the  <code class="code">total_timeout</code> .
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005frecord_005fget_005fdiscarded-1"><span>gnutls_record_get_discarded<a class="copiable-link" href="#gnutls_005frecord_005fget_005fdiscarded-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005frecord_005fget_005fdiscarded"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frecord_005fget_005fdiscarded"><span class="category-def">Function: </span><span><code class="def-type">unsigned int</code> <strong class="def-name">gnutls_record_get_discarded</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005frecord_005fget_005fdiscarded"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>Returns the number of discarded packets in a
DTLS connection.
</p>
<p><strong class="strong">Returns:</strong> The number of discarded packets.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>


<hr>
</div>
<div class="section-level-extent" id="X509-certificate-API">
<div class="nav-panel">
<p>
Next: <a href="#PKCS-7-API" accesskey="n" rel="next"><abbr class="acronym">PKCS</abbr> 7 API</a>, Previous: <a href="#Datagram-TLS-API" accesskey="p" rel="prev">Datagram TLS API</a>, Up: <a href="#API-reference" accesskey="u" rel="up">API reference</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="X_002e509-certificate-API"><span>E.3 <abbr class="acronym">X.509</abbr> certificate API<a class="copiable-link" href="#X_002e509-certificate-API"> &para;</a></span></h3>
<a class="index-entry-id" id="index-X_002e509-Functions"></a>

<p>The following functions are to be used for <abbr class="acronym">X.509</abbr> certificate handling.
Their prototypes lie in <samp class="file">gnutls/x509.h</samp>.
</p>

<h4 class="subheading" id="gnutls_005fcertificate_005fget_005ftrust_005flist-1"><span>gnutls_certificate_get_trust_list<a class="copiable-link" href="#gnutls_005fcertificate_005fget_005ftrust_005flist-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fget_005ftrust_005flist"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fget_005ftrust_005flist"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_certificate_get_trust_list</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">res</var>, gnutls_x509_trust_list_t * <var class="var">tlist</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fget_005ftrust_005flist"> &para;</a></span></dt>
<dd><p><var class="var">res</var>: is a <code class="code">gnutls_certificate_credentials_t</code>  type.
</p>
<p><var class="var">tlist</var>: Location where to store the trust list.
</p>
<p>Obtains the list of trusted certificates stored in  <code class="code">res</code> and writes a
pointer to it to the location  <code class="code">tlist</code> . The pointer will point to memory
internal to  <code class="code">res</code> , and must not be deinitialized. It will be automatically
deallocated when the  <code class="code">res</code> structure is deinitialized.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fset_005ftrust_005flist-1"><span>gnutls_certificate_set_trust_list<a class="copiable-link" href="#gnutls_005fcertificate_005fset_005ftrust_005flist-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fset_005ftrust_005flist"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fset_005ftrust_005flist"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_certificate_set_trust_list</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">res</var>, gnutls_x509_trust_list_t <var class="var">tlist</var>, unsigned <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fset_005ftrust_005flist"> &para;</a></span></dt>
<dd><p><var class="var">res</var>: is a <code class="code">gnutls_certificate_credentials_t</code>  type.
</p>
<p><var class="var">tlist</var>: is a <code class="code">gnutls_x509_trust_list_t</code>  type
</p>
<p><var class="var">flags</var>: must be zero
</p>
<p>This function sets a trust list in the gnutls_certificate_credentials_t type.
</p>
<p>Note that the  <code class="code">tlist</code> will become part of the credentials
structure and must not be deallocated. It will be automatically deallocated
when the  <code class="code">res</code> structure is deinitialized.
</p>
<p><strong class="strong">Since:</strong> 3.2.2
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fverification_005fprofile_005fget_005fid-1"><span>gnutls_certificate_verification_profile_get_id<a class="copiable-link" href="#gnutls_005fcertificate_005fverification_005fprofile_005fget_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fverification_005fprofile_005fget_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fverification_005fprofile_005fget_005fid"><span class="category-def">Function: </span><span><code class="def-type">gnutls_certificate_verification_profiles_t</code> <strong class="def-name">gnutls_certificate_verification_profile_get_id</strong> <code class="def-code-arguments">(const char * <var class="var">name</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fverification_005fprofile_005fget_005fid"> &para;</a></span></dt>
<dd><p><var class="var">name</var>: is a profile name
</p>
<p>Convert a string to a <code class="code">gnutls_certificate_verification_profiles_t</code>  value.  The names are
compared in a case insensitive way.
</p>
<p><strong class="strong">Returns:</strong> a <code class="code">gnutls_certificate_verification_profiles_t</code>  id of the specified profile,
or <code class="code">GNUTLS_PROFILE_UNKNOWN</code>  on failure.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fverification_005fprofile_005fget_005fname-1"><span>gnutls_certificate_verification_profile_get_name<a class="copiable-link" href="#gnutls_005fcertificate_005fverification_005fprofile_005fget_005fname-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fverification_005fprofile_005fget_005fname"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fverification_005fprofile_005fget_005fname"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_certificate_verification_profile_get_name</strong> <code class="def-code-arguments">(gnutls_certificate_verification_profiles_t <var class="var">id</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fverification_005fprofile_005fget_005fname"> &para;</a></span></dt>
<dd><p><var class="var">id</var>: is a profile ID
</p>
<p>Convert a <code class="code">gnutls_certificate_verification_profiles_t</code>  value to a string.
</p>
<p><strong class="strong">Returns:</strong> a string that contains the name of the specified profile or <code class="code">NULL</code> .
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs8_005finfo-1"><span>gnutls_pkcs8_info<a class="copiable-link" href="#gnutls_005fpkcs8_005finfo-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs8_005finfo"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs8_005finfo"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs8_info</strong> <code class="def-code-arguments">(const gnutls_datum_t * <var class="var">data</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, unsigned int * <var class="var">schema</var>, unsigned int * <var class="var">cipher</var>, void * <var class="var">salt</var>, unsigned int * <var class="var">salt_size</var>, unsigned int * <var class="var">iter_count</var>, char ** <var class="var">oid</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs8_005finfo"> &para;</a></span></dt>
<dd><p><var class="var">data</var>: Holds the PKCS <code class="code">8</code>  data
</p>
<p><var class="var">format</var>: the format of the PKCS <code class="code">8</code>  data
</p>
<p><var class="var">schema</var>: indicate the schema as one of <code class="code">gnutls_pkcs_encrypt_flags_t</code> 
</p>
<p><var class="var">cipher</var>: the cipher used as <code class="code">gnutls_cipher_algorithm_t</code> 
</p>
<p><var class="var">salt</var>: PBKDF2 salt (if non-NULL then  <code class="code">salt_size</code> initially holds its size)
</p>
<p><var class="var">salt_size</var>: PBKDF2 salt size
</p>
<p><var class="var">iter_count</var>: PBKDF2 iteration count
</p>
<p><var class="var">oid</var>: if non-NULL it will contain an allocated null-terminated variable with the OID
</p>
<p>This function will provide information on the algorithms used
in a particular PKCS <code class="code">8</code>  structure. If the structure algorithms
are unknown the code <code class="code">GNUTLS_E_UNKNOWN_CIPHER_TYPE</code>  will be returned,
and only  <code class="code">oid</code> , will be set. That is,  <code class="code">oid</code> will be set on encrypted PKCS <code class="code">8</code> 
structures whether supported or not. It must be deinitialized using <code class="code">gnutls_free()</code> .
The other variables are only set on supported structures.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_INVALID_REQUEST</code>  if the provided structure isn&rsquo;t an encrypted key,
<code class="code">GNUTLS_E_UNKNOWN_CIPHER_TYPE</code>  if the structure&rsquo;s encryption isn&rsquo;t supported, or
another negative error code in case of a failure. Zero on success.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs_005fschema_005fget_005fname-1"><span>gnutls_pkcs_schema_get_name<a class="copiable-link" href="#gnutls_005fpkcs_005fschema_005fget_005fname-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs_005fschema_005fget_005fname"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs_005fschema_005fget_005fname"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_pkcs_schema_get_name</strong> <code class="def-code-arguments">(unsigned int <var class="var">schema</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs_005fschema_005fget_005fname"> &para;</a></span></dt>
<dd><p><var class="var">schema</var>: Holds the PKCS <code class="code">12</code>  or PBES2 schema (<code class="code">gnutls_pkcs_encrypt_flags_t</code> )
</p>
<p>This function will return a human readable description of the
PKCS12 or PBES2 schema.
</p>
<p><strong class="strong">Returns:</strong> a constraint string or <code class="code">NULL</code>  on error.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs_005fschema_005fget_005foid-1"><span>gnutls_pkcs_schema_get_oid<a class="copiable-link" href="#gnutls_005fpkcs_005fschema_005fget_005foid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs_005fschema_005fget_005foid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs_005fschema_005fget_005foid"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_pkcs_schema_get_oid</strong> <code class="def-code-arguments">(unsigned int <var class="var">schema</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs_005fschema_005fget_005foid"> &para;</a></span></dt>
<dd><p><var class="var">schema</var>: Holds the PKCS <code class="code">12</code>  or PBES2 schema (<code class="code">gnutls_pkcs_encrypt_flags_t</code> )
</p>
<p>This function will return the object identifier of the
PKCS12 or PBES2 schema.
</p>
<p><strong class="strong">Returns:</strong> a constraint string or <code class="code">NULL</code>  on error.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsession_005fset_005fverify_005foutput_005ffunction-1"><span>gnutls_session_set_verify_output_function<a class="copiable-link" href="#gnutls_005fsession_005fset_005fverify_005foutput_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsession_005fset_005fverify_005foutput_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsession_005fset_005fverify_005foutput_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_session_set_verify_output_function</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, gnutls_verify_output_function * <var class="var">func</var>)</code><a class="copiable-link" href="#index-gnutls_005fsession_005fset_005fverify_005foutput_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_x509_trust_list_t</code>  type.
</p>
<p><var class="var">func</var>: is the callback function
</p>
<p>This function sets a callback to be called when the peer&rsquo;s certificate
chain has to be verified and full path to the trusted root has to be
printed.
</p>
<p>The callback&rsquo;s function prototype is defined in &lsquo;x509.h&rsquo;:
int (*callback)(
gnutls_x509_crt_t cert,
gnutls_x509_crt_t issuer,
gnutls_x509_crl_t crl,
unsigned int verification_output);
</p>
<p>If the callback function is provided then gnutls will call it, in the
certificate verification procedure.
To verify the certificate chain and print its path uptp the trusted root,
functions such as <code class="code">gnutls_certificate_verify_peers()</code> ,
<code class="code">gnutls_x509_trust_list_verify_crt()</code> , and <code class="code">gnutls_x509_trust_list_verify_crt2()</code> 
can be used. The callback is set in <code class="code">_gnutls_verify_crt_status()</code>  and
<code class="code">_gnutls_pkcs11_verify_crt_status()</code> .
</p>
<p><strong class="strong">Since:</strong> 3.7.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsubject_005falt_005fnames_005fdeinit-1"><span>gnutls_subject_alt_names_deinit<a class="copiable-link" href="#gnutls_005fsubject_005falt_005fnames_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsubject_005falt_005fnames_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsubject_005falt_005fnames_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_subject_alt_names_deinit</strong> <code class="def-code-arguments">(gnutls_subject_alt_names_t <var class="var">sans</var>)</code><a class="copiable-link" href="#index-gnutls_005fsubject_005falt_005fnames_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">sans</var>: The alternative names
</p>
<p>This function will deinitialize an alternative names structure.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsubject_005falt_005fnames_005fget-1"><span>gnutls_subject_alt_names_get<a class="copiable-link" href="#gnutls_005fsubject_005falt_005fnames_005fget-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsubject_005falt_005fnames_005fget"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsubject_005falt_005fnames_005fget"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_subject_alt_names_get</strong> <code class="def-code-arguments">(gnutls_subject_alt_names_t <var class="var">sans</var>, unsigned int <var class="var">seq</var>, unsigned int * <var class="var">san_type</var>, gnutls_datum_t * <var class="var">san</var>, gnutls_datum_t * <var class="var">othername_oid</var>)</code><a class="copiable-link" href="#index-gnutls_005fsubject_005falt_005fnames_005fget"> &para;</a></span></dt>
<dd><p><var class="var">sans</var>: The alternative names
</p>
<p><var class="var">seq</var>: The index of the name to get
</p>
<p><var class="var">san_type</var>: Will hold the type of the name (of <code class="code">gnutls_subject_alt_names_t</code> )
</p>
<p><var class="var">san</var>: The alternative name data (should be treated as constant)
</p>
<p><var class="var">othername_oid</var>: The object identifier if  <code class="code">san_type</code> is <code class="code">GNUTLS_SAN_OTHERNAME</code>  (should be treated as constant)
</p>
<p>This function will return a specific alternative name as stored in
the  <code class="code">sans</code> type. The returned values should be treated as constant
and valid for the lifetime of  <code class="code">sans</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> 
if the index is out of bounds, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsubject_005falt_005fnames_005finit-1"><span>gnutls_subject_alt_names_init<a class="copiable-link" href="#gnutls_005fsubject_005falt_005fnames_005finit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsubject_005falt_005fnames_005finit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsubject_005falt_005fnames_005finit"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_subject_alt_names_init</strong> <code class="def-code-arguments">(gnutls_subject_alt_names_t * <var class="var">sans</var>)</code><a class="copiable-link" href="#index-gnutls_005fsubject_005falt_005fnames_005finit"> &para;</a></span></dt>
<dd><p><var class="var">sans</var>: The alternative names
</p>
<p>This function will initialize an alternative names structure.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsubject_005falt_005fnames_005fset-1"><span>gnutls_subject_alt_names_set<a class="copiable-link" href="#gnutls_005fsubject_005falt_005fnames_005fset-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsubject_005falt_005fnames_005fset"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsubject_005falt_005fnames_005fset"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_subject_alt_names_set</strong> <code class="def-code-arguments">(gnutls_subject_alt_names_t <var class="var">sans</var>, unsigned int <var class="var">san_type</var>, const gnutls_datum_t * <var class="var">san</var>, const char * <var class="var">othername_oid</var>)</code><a class="copiable-link" href="#index-gnutls_005fsubject_005falt_005fnames_005fset"> &para;</a></span></dt>
<dd><p><var class="var">sans</var>: The alternative names
</p>
<p><var class="var">san_type</var>: The type of the name (of <code class="code">gnutls_subject_alt_names_t</code> )
</p>
<p><var class="var">san</var>: The alternative name data
</p>
<p><var class="var">othername_oid</var>: The object identifier if  <code class="code">san_type</code> is <code class="code">GNUTLS_SAN_OTHERNAME</code> 
</p>
<p>This function will store the specified alternative name in
the  <code class="code">sans</code> .
</p>
<p>Since version 3.5.7 the <code class="code">GNUTLS_SAN_RFC822NAME</code> , <code class="code">GNUTLS_SAN_DNSNAME</code> , and
<code class="code">GNUTLS_SAN_OTHERNAME_XMPP</code>  are converted to ACE format when necessary.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0), otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005faia_005fdeinit-1"><span>gnutls_x509_aia_deinit<a class="copiable-link" href="#gnutls_005fx509_005faia_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005faia_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005faia_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_x509_aia_deinit</strong> <code class="def-code-arguments">(gnutls_x509_aia_t <var class="var">aia</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005faia_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">aia</var>: The authority info access
</p>
<p>This function will deinitialize an authority info access type.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005faia_005fget-1"><span>gnutls_x509_aia_get<a class="copiable-link" href="#gnutls_005fx509_005faia_005fget-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005faia_005fget"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005faia_005fget"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_aia_get</strong> <code class="def-code-arguments">(gnutls_x509_aia_t <var class="var">aia</var>, unsigned int <var class="var">seq</var>, gnutls_datum_t * <var class="var">oid</var>, unsigned * <var class="var">san_type</var>, gnutls_datum_t * <var class="var">san</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005faia_005fget"> &para;</a></span></dt>
<dd><p><var class="var">aia</var>: The authority info access
</p>
<p><var class="var">seq</var>: specifies the sequence number of the access descriptor (0 for the first one, 1 for the second etc.)
</p>
<p><var class="var">oid</var>: the type of available data; to be treated as constant.
</p>
<p><var class="var">san_type</var>: Will hold the type of the name of <code class="code">gnutls_subject_alt_names_t</code>  (may be null).
</p>
<p><var class="var">san</var>: the access location name; to be treated as constant (may be null).
</p>
<p>This function reads from the Authority Information Access type.
</p>
<p>The  <code class="code">seq</code> input parameter is used to indicate which member of the
sequence the caller is interested in.  The first member is 0, the
second member 1 and so on.  When the  <code class="code">seq</code> value is out of bounds,
<code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  is returned.
</p>
<p>Typically  <code class="code">oid</code> is <code class="code">GNUTLS_OID_AD_CAISSUERS</code>  or <code class="code">GNUTLS_OID_AD_OCSP</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005faia_005finit-1"><span>gnutls_x509_aia_init<a class="copiable-link" href="#gnutls_005fx509_005faia_005finit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005faia_005finit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005faia_005finit"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_aia_init</strong> <code class="def-code-arguments">(gnutls_x509_aia_t * <var class="var">aia</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005faia_005finit"> &para;</a></span></dt>
<dd><p><var class="var">aia</var>: The authority info access
</p>
<p>This function will initialize an authority info access type.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005faia_005fset-1"><span>gnutls_x509_aia_set<a class="copiable-link" href="#gnutls_005fx509_005faia_005fset-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005faia_005fset"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005faia_005fset"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_aia_set</strong> <code class="def-code-arguments">(gnutls_x509_aia_t <var class="var">aia</var>, const char * <var class="var">oid</var>, unsigned <var class="var">san_type</var>, const gnutls_datum_t * <var class="var">san</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005faia_005fset"> &para;</a></span></dt>
<dd><p><var class="var">aia</var>: The authority info access
</p>
<p><var class="var">oid</var>: the type of data.
</p>
<p><var class="var">san_type</var>: The type of the name (of <code class="code">gnutls_subject_alt_names_t</code> )
</p>
<p><var class="var">san</var>: The alternative name data
</p>
<p>This function will store the specified alternative name in
the  <code class="code">aia</code> type. 
</p>
<p>Typically the value for  <code class="code">oid</code> should be <code class="code">GNUTLS_OID_AD_OCSP</code> , or
<code class="code">GNUTLS_OID_AD_CAISSUERS</code> .
</p>
<p>Since version 3.5.7 the <code class="code">GNUTLS_SAN_RFC822NAME</code> , and <code class="code">GNUTLS_SAN_DNSNAME</code> ,
are converted to ACE format when necessary.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0), otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005faki_005fdeinit-1"><span>gnutls_x509_aki_deinit<a class="copiable-link" href="#gnutls_005fx509_005faki_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005faki_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005faki_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_x509_aki_deinit</strong> <code class="def-code-arguments">(gnutls_x509_aki_t <var class="var">aki</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005faki_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">aki</var>: The authority key identifier type
</p>
<p>This function will deinitialize an authority key identifier.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005faki_005fget_005fcert_005fissuer-1"><span>gnutls_x509_aki_get_cert_issuer<a class="copiable-link" href="#gnutls_005fx509_005faki_005fget_005fcert_005fissuer-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005faki_005fget_005fcert_005fissuer"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005faki_005fget_005fcert_005fissuer"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_aki_get_cert_issuer</strong> <code class="def-code-arguments">(gnutls_x509_aki_t <var class="var">aki</var>, unsigned int <var class="var">seq</var>, unsigned int * <var class="var">san_type</var>, gnutls_datum_t * <var class="var">san</var>, gnutls_datum_t * <var class="var">othername_oid</var>, gnutls_datum_t * <var class="var">serial</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005faki_005fget_005fcert_005fissuer"> &para;</a></span></dt>
<dd><p><var class="var">aki</var>: The authority key ID
</p>
<p><var class="var">seq</var>: The index of the name to get
</p>
<p><var class="var">san_type</var>: Will hold the type of the name (of <code class="code">gnutls_subject_alt_names_t</code> )
</p>
<p><var class="var">san</var>: The alternative name data
</p>
<p><var class="var">othername_oid</var>: The object identifier if  <code class="code">san_type</code> is <code class="code">GNUTLS_SAN_OTHERNAME</code> 
</p>
<p><var class="var">serial</var>: The authorityCertSerialNumber number
</p>
<p>This function will return a specific authorityCertIssuer name as stored in
the  <code class="code">aki</code> type, as well as the authorityCertSerialNumber. All the returned
values should be treated as constant, and may be set to <code class="code">NULL</code>  when are not required.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> 
if the index is out of bounds, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005faki_005fget_005fid-1"><span>gnutls_x509_aki_get_id<a class="copiable-link" href="#gnutls_005fx509_005faki_005fget_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005faki_005fget_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005faki_005fget_005fid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_aki_get_id</strong> <code class="def-code-arguments">(gnutls_x509_aki_t <var class="var">aki</var>, gnutls_datum_t * <var class="var">id</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005faki_005fget_005fid"> &para;</a></span></dt>
<dd><p><var class="var">aki</var>: The authority key ID
</p>
<p><var class="var">id</var>: Will hold the identifier
</p>
<p>This function will return the key identifier as stored in
the  <code class="code">aki</code> type. The identifier should be treated as constant.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> 
if the index is out of bounds, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005faki_005finit-1"><span>gnutls_x509_aki_init<a class="copiable-link" href="#gnutls_005fx509_005faki_005finit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005faki_005finit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005faki_005finit"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_aki_init</strong> <code class="def-code-arguments">(gnutls_x509_aki_t * <var class="var">aki</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005faki_005finit"> &para;</a></span></dt>
<dd><p><var class="var">aki</var>: The authority key ID type
</p>
<p>This function will initialize an authority key ID.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005faki_005fset_005fcert_005fissuer-1"><span>gnutls_x509_aki_set_cert_issuer<a class="copiable-link" href="#gnutls_005fx509_005faki_005fset_005fcert_005fissuer-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005faki_005fset_005fcert_005fissuer"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005faki_005fset_005fcert_005fissuer"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_aki_set_cert_issuer</strong> <code class="def-code-arguments">(gnutls_x509_aki_t <var class="var">aki</var>, unsigned int <var class="var">san_type</var>, const gnutls_datum_t * <var class="var">san</var>, const char * <var class="var">othername_oid</var>, const gnutls_datum_t * <var class="var">serial</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005faki_005fset_005fcert_005fissuer"> &para;</a></span></dt>
<dd><p><var class="var">aki</var>: The authority key ID
</p>
<p><var class="var">san_type</var>: the type of the name (of <code class="code">gnutls_subject_alt_names_t</code> ), may be null
</p>
<p><var class="var">san</var>: The alternative name data
</p>
<p><var class="var">othername_oid</var>: The object identifier if  <code class="code">san_type</code> is <code class="code">GNUTLS_SAN_OTHERNAME</code> 
</p>
<p><var class="var">serial</var>: The authorityCertSerialNumber number (may be null)
</p>
<p>This function will set the authorityCertIssuer name and the authorityCertSerialNumber 
to be stored in the  <code class="code">aki</code> type. When storing multiple names, the serial
should be set on the first call, and subsequent calls should use a <code class="code">NULL</code>  serial.
</p>
<p>Since version 3.5.7 the <code class="code">GNUTLS_SAN_RFC822NAME</code> , <code class="code">GNUTLS_SAN_DNSNAME</code> , and
<code class="code">GNUTLS_SAN_OTHERNAME_XMPP</code>  are converted to ACE format when necessary.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005faki_005fset_005fid-1"><span>gnutls_x509_aki_set_id<a class="copiable-link" href="#gnutls_005fx509_005faki_005fset_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005faki_005fset_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005faki_005fset_005fid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_aki_set_id</strong> <code class="def-code-arguments">(gnutls_x509_aki_t <var class="var">aki</var>, const gnutls_datum_t * <var class="var">id</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005faki_005fset_005fid"> &para;</a></span></dt>
<dd><p><var class="var">aki</var>: The authority key ID
</p>
<p><var class="var">id</var>: the key identifier
</p>
<p>This function will set the keyIdentifier to be stored in the  <code class="code">aki</code> type.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcidr_005fto_005frfc5280-1"><span>gnutls_x509_cidr_to_rfc5280<a class="copiable-link" href="#gnutls_005fx509_005fcidr_005fto_005frfc5280-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcidr_005fto_005frfc5280"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcidr_005fto_005frfc5280"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_cidr_to_rfc5280</strong> <code class="def-code-arguments">(const char * <var class="var">cidr</var>, gnutls_datum_t * <var class="var">cidr_rfc5280</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcidr_005fto_005frfc5280"> &para;</a></span></dt>
<dd><p><var class="var">cidr</var>: CIDR in RFC4632 format (IP/prefix), null-terminated
</p>
<p><var class="var">cidr_rfc5280</var>: CIDR range converted to RFC5280 format
</p>
<p>This function will convert text CIDR range with prefix (such as &rsquo;10.0.0.0/8&rsquo;)
to RFC5280 (IP address in network byte order followed by its network mask).
Works for both IPv4 and IPv6.
</p>
<p>The resulting object is directly usable for IP name constraints usage,
for example in functions <code class="code">gnutls_x509_name_constraints_add_permitted</code> 
or <code class="code">gnutls_x509_name_constraints_add_excluded</code> .
</p>
<p>The data in datum needs to be deallocated using <code class="code">gnutls_free()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.5.4
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fcheck_005fissuer-1"><span>gnutls_x509_crl_check_issuer<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fcheck_005fissuer-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fcheck_005fissuer"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fcheck_005fissuer"><span class="category-def">Function: </span><span><code class="def-type">unsigned</code> <strong class="def-name">gnutls_x509_crl_check_issuer</strong> <code class="def-code-arguments">(gnutls_x509_crl_t <var class="var">crl</var>, gnutls_x509_crt_t <var class="var">issuer</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fcheck_005fissuer"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: is the CRL to be checked
</p>
<p><var class="var">issuer</var>: is the certificate of a possible issuer
</p>
<p>This function will check if the given CRL was issued by the given
issuer certificate.
</p>
<p><strong class="strong">Returns:</strong> true (1) if the given CRL was issued by the given issuer,
and false (0) if not.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fdeinit-1"><span>gnutls_x509_crl_deinit<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_x509_crl_deinit</strong> <code class="def-code-arguments">(gnutls_x509_crl_t <var class="var">crl</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: The data to be deinitialized
</p>
<p>This function will deinitialize a CRL structure.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fdist_005fpoints_005fdeinit-1"><span>gnutls_x509_crl_dist_points_deinit<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fdist_005fpoints_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fdist_005fpoints_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fdist_005fpoints_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_x509_crl_dist_points_deinit</strong> <code class="def-code-arguments">(gnutls_x509_crl_dist_points_t <var class="var">cdp</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fdist_005fpoints_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">cdp</var>: The CRL distribution points
</p>
<p>This function will deinitialize a CRL distribution points type.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fdist_005fpoints_005fget-1"><span>gnutls_x509_crl_dist_points_get<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fdist_005fpoints_005fget-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fdist_005fpoints_005fget"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fdist_005fpoints_005fget"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_dist_points_get</strong> <code class="def-code-arguments">(gnutls_x509_crl_dist_points_t <var class="var">cdp</var>, unsigned int <var class="var">seq</var>, unsigned int * <var class="var">type</var>, gnutls_datum_t * <var class="var">san</var>, unsigned int * <var class="var">reasons</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fdist_005fpoints_005fget"> &para;</a></span></dt>
<dd><p><var class="var">cdp</var>: The CRL distribution points
</p>
<p><var class="var">seq</var>: specifies the sequence number of the distribution point (0 for the first one, 1 for the second etc.)
</p>
<p><var class="var">type</var>: The name type of the corresponding name (gnutls_x509_subject_alt_name_t)
</p>
<p><var class="var">san</var>: The distribution point names (to be treated as constant)
</p>
<p><var class="var">reasons</var>: Revocation reasons. An ORed sequence of flags from <code class="code">gnutls_x509_crl_reason_flags_t</code> .
</p>
<p>This function retrieves the individual CRL distribution points (2.5.29.31),
contained in provided type. 
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> 
if the index is out of bounds, otherwise a negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fdist_005fpoints_005finit-1"><span>gnutls_x509_crl_dist_points_init<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fdist_005fpoints_005finit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fdist_005fpoints_005finit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fdist_005fpoints_005finit"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_dist_points_init</strong> <code class="def-code-arguments">(gnutls_x509_crl_dist_points_t * <var class="var">cdp</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fdist_005fpoints_005finit"> &para;</a></span></dt>
<dd><p><var class="var">cdp</var>: The CRL distribution points
</p>
<p>This function will initialize a CRL distribution points type.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fdist_005fpoints_005fset-1"><span>gnutls_x509_crl_dist_points_set<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fdist_005fpoints_005fset-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fdist_005fpoints_005fset"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fdist_005fpoints_005fset"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_dist_points_set</strong> <code class="def-code-arguments">(gnutls_x509_crl_dist_points_t <var class="var">cdp</var>, gnutls_x509_subject_alt_name_t <var class="var">type</var>, const gnutls_datum_t * <var class="var">san</var>, unsigned int <var class="var">reasons</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fdist_005fpoints_005fset"> &para;</a></span></dt>
<dd><p><var class="var">cdp</var>: The CRL distribution points
</p>
<p><var class="var">type</var>: The type of the name (of <code class="code">gnutls_subject_alt_names_t</code> )
</p>
<p><var class="var">san</var>: The point name data
</p>
<p><var class="var">reasons</var>: Revocation reasons. An ORed sequence of flags from <code class="code">gnutls_x509_crl_reason_flags_t</code> .
</p>
<p>This function will store the specified CRL distribution point value
the  <code class="code">cdp</code> type.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0), otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fexport-1"><span>gnutls_x509_crl_export<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fexport-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fexport"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fexport"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_export</strong> <code class="def-code-arguments">(gnutls_x509_crl_t <var class="var">crl</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, void * <var class="var">output_data</var>, size_t * <var class="var">output_data_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fexport"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: Holds the revocation list
</p>
<p><var class="var">format</var>: the format of output params. One of PEM or DER.
</p>
<p><var class="var">output_data</var>: will contain a private key PEM or DER encoded
</p>
<p><var class="var">output_data_size</var>: holds the size of output_data (and will
be replaced by the actual size of parameters)
</p>
<p>This function will export the revocation list to DER or PEM format.
</p>
<p>If the buffer provided is not long enough to hold the output, then
<code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  will be returned.
</p>
<p>If the structure is PEM encoded, it will have a header
of &quot;BEGIN X509 CRL&quot;.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fexport2-1"><span>gnutls_x509_crl_export2<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fexport2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fexport2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fexport2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_export2</strong> <code class="def-code-arguments">(gnutls_x509_crl_t <var class="var">crl</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, gnutls_datum_t * <var class="var">out</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fexport2"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: Holds the revocation list
</p>
<p><var class="var">format</var>: the format of output params. One of PEM or DER.
</p>
<p><var class="var">out</var>: will contain a private key PEM or DER encoded
</p>
<p>This function will export the revocation list to DER or PEM format.
</p>
<p>The output buffer is allocated using <code class="code">gnutls_malloc()</code> .
</p>
<p>If the structure is PEM encoded, it will have a header
of &quot;BEGIN X509 CRL&quot;.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p>Since 3.1.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fget_005fauthority_005fkey_005fgn_005fserial-1"><span>gnutls_x509_crl_get_authority_key_gn_serial<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fget_005fauthority_005fkey_005fgn_005fserial-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fget_005fauthority_005fkey_005fgn_005fserial"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fget_005fauthority_005fkey_005fgn_005fserial"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_get_authority_key_gn_serial</strong> <code class="def-code-arguments">(gnutls_x509_crl_t <var class="var">crl</var>, unsigned int <var class="var">seq</var>, void * <var class="var">alt</var>, size_t * <var class="var">alt_size</var>, unsigned int * <var class="var">alt_type</var>, void * <var class="var">serial</var>, size_t * <var class="var">serial_size</var>, unsigned int * <var class="var">critical</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fget_005fauthority_005fkey_005fgn_005fserial"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: should contain a <code class="code">gnutls_x509_crl_t</code>  type
</p>
<p><var class="var">seq</var>: specifies the sequence number of the alt name (0 for the first one, 1 for the second etc.)
</p>
<p><var class="var">alt</var>: is the place where the alternative name will be copied to
</p>
<p><var class="var">alt_size</var>: holds the size of alt.
</p>
<p><var class="var">alt_type</var>: holds the type of the alternative name (one of gnutls_x509_subject_alt_name_t).
</p>
<p><var class="var">serial</var>: buffer to store the serial number (may be null)
</p>
<p><var class="var">serial_size</var>: Holds the size of the serial field (may be null)
</p>
<p><var class="var">critical</var>: will be non-zero if the extension is marked as critical (may be null)
</p>
<p>This function will return the X.509 authority key
identifier when stored as a general name (authorityCertIssuer) 
and serial number.
</p>
<p>Because more than one general names might be stored
 <code class="code">seq</code> can be used as a counter to request them all until 
<code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  is returned.
</p>
<p><strong class="strong">Returns:</strong> Returns 0 on success, or an error code.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fget_005fauthority_005fkey_005fid-1"><span>gnutls_x509_crl_get_authority_key_id<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fget_005fauthority_005fkey_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fget_005fauthority_005fkey_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fget_005fauthority_005fkey_005fid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_get_authority_key_id</strong> <code class="def-code-arguments">(gnutls_x509_crl_t <var class="var">crl</var>, void * <var class="var">id</var>, size_t * <var class="var">id_size</var>, unsigned int * <var class="var">critical</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fget_005fauthority_005fkey_005fid"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: should contain a <code class="code">gnutls_x509_crl_t</code>  type
</p>
<p><var class="var">id</var>: The place where the identifier will be copied
</p>
<p><var class="var">id_size</var>: Holds the size of the result field.
</p>
<p><var class="var">critical</var>: will be non-zero if the extension is marked as critical
(may be null)
</p>
<p>This function will return the CRL authority&rsquo;s key identifier.  This
is obtained by the X.509 Authority Key identifier extension field
(2.5.29.35).  Note that this function 
only returns the keyIdentifier field of the extension and
<code class="code">GNUTLS_E_X509_UNSUPPORTED_EXTENSION</code> , if the extension contains
the name and serial number of the certificate. In that case
<code class="code">gnutls_x509_crl_get_authority_key_gn_serial()</code>  may be used.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error code in case of an error.
</p>
<p><strong class="strong">Since:</strong> 2.8.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fget_005fcrt_005fcount-1"><span>gnutls_x509_crl_get_crt_count<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fget_005fcrt_005fcount-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fget_005fcrt_005fcount"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fget_005fcrt_005fcount"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_get_crt_count</strong> <code class="def-code-arguments">(gnutls_x509_crl_t <var class="var">crl</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fget_005fcrt_005fcount"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: should contain a <code class="code">gnutls_x509_crl_t</code>  type
</p>
<p>This function will return the number of revoked certificates in the
given CRL.
</p>
<p><strong class="strong">Returns:</strong> number of certificates, a negative error code on failure.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fget_005fcrt_005fserial-1"><span>gnutls_x509_crl_get_crt_serial<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fget_005fcrt_005fserial-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fget_005fcrt_005fserial"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fget_005fcrt_005fserial-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_get_crt_serial</strong> <code class="def-code-arguments">(gnutls_x509_crl_t <var class="var">crl</var>, unsigned <var class="var">indx</var>, unsigned char * <var class="var">serial</var>, size_t * <var class="var">serial_size</var>, time_t * <var class="var">t</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fget_005fcrt_005fserial-1"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: should contain a <code class="code">gnutls_x509_crl_t</code>  type
</p>
<p><var class="var">indx</var>: the index of the certificate to extract (starting from 0)
</p>
<p><var class="var">serial</var>: where the serial number will be copied
</p>
<p><var class="var">serial_size</var>: initially holds the size of serial
</p>
<p><var class="var">t</var>: if non null, will hold the time this certificate was revoked
</p>
<p>This function will retrieve the serial number of the specified, by
the index, revoked certificate.
</p>
<p>Note that this function will have performance issues in large sequences
of revoked certificates. In that case use <code class="code">gnutls_x509_crl_iter_crt_serial()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fget_005fdn_005foid-1"><span>gnutls_x509_crl_get_dn_oid<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fget_005fdn_005foid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fget_005fdn_005foid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fget_005fdn_005foid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_get_dn_oid</strong> <code class="def-code-arguments">(gnutls_x509_crl_t <var class="var">crl</var>, unsigned <var class="var">indx</var>, void * <var class="var">oid</var>, size_t * <var class="var">sizeof_oid</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fget_005fdn_005foid"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: should contain a gnutls_x509_crl_t type
</p>
<p><var class="var">indx</var>: Specifies which DN OID to send. Use (0) to get the first one.
</p>
<p><var class="var">oid</var>: a pointer to store the OID (may be null)
</p>
<p><var class="var">sizeof_oid</var>: initially holds the size of &rsquo;oid&rsquo;
</p>
<p>This function will extract the requested OID of the name of the CRL
issuer, specified by the given index.
</p>
<p>If oid is null then only the size will be filled.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  if the provided buffer is
not long enough, and in that case the sizeof_oid will be updated
with the required size.  On success 0 is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fget_005fextension_005fdata-1"><span>gnutls_x509_crl_get_extension_data<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fget_005fextension_005fdata-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fget_005fextension_005fdata"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fget_005fextension_005fdata"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_get_extension_data</strong> <code class="def-code-arguments">(gnutls_x509_crl_t <var class="var">crl</var>, unsigned <var class="var">indx</var>, void * <var class="var">data</var>, size_t * <var class="var">sizeof_data</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fget_005fextension_005fdata"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: should contain a <code class="code">gnutls_x509_crl_t</code>  type
</p>
<p><var class="var">indx</var>: Specifies which extension OID to send. Use (0) to get the first one.
</p>
<p><var class="var">data</var>: a pointer to a structure to hold the data (may be null)
</p>
<p><var class="var">sizeof_data</var>: initially holds the size of  <code class="code">oid</code> 
</p>
<p>This function will return the requested extension data in the CRL.
The extension data will be stored as a string in the provided
buffer.
</p>
<p>Use <code class="code">gnutls_x509_crl_get_extension_info()</code>  to extract the OID and
critical flag.  Use <code class="code">gnutls_x509_crl_get_extension_info()</code>  instead,
if you want to get data indexed by the extension OID rather than
sequence.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error code in case of an error.  If your have reached the
last extension available <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> 
will be returned.
</p>
<p><strong class="strong">Since:</strong> 2.8.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fget_005fextension_005fdata2-1"><span>gnutls_x509_crl_get_extension_data2<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fget_005fextension_005fdata2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fget_005fextension_005fdata2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fget_005fextension_005fdata2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_get_extension_data2</strong> <code class="def-code-arguments">(gnutls_x509_crl_t <var class="var">crl</var>, unsigned <var class="var">indx</var>, gnutls_datum_t * <var class="var">data</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fget_005fextension_005fdata2"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: should contain a <code class="code">gnutls_x509_crl_t</code>  type
</p>
<p><var class="var">indx</var>: Specifies which extension OID to read. Use (0) to get the first one.
</p>
<p><var class="var">data</var>: will contain the extension DER-encoded data
</p>
<p>This function will return the requested by the index extension data in the
certificate revocation list.  The extension data will be allocated using
<code class="code">gnutls_malloc()</code> .
</p>
<p>Use <code class="code">gnutls_x509_crt_get_extension_info()</code>  to extract the OID.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned.  If you have reached the
last extension available <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> 
will be returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fget_005fextension_005finfo-1"><span>gnutls_x509_crl_get_extension_info<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fget_005fextension_005finfo-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fget_005fextension_005finfo"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fget_005fextension_005finfo"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_get_extension_info</strong> <code class="def-code-arguments">(gnutls_x509_crl_t <var class="var">crl</var>, unsigned <var class="var">indx</var>, void * <var class="var">oid</var>, size_t * <var class="var">sizeof_oid</var>, unsigned int * <var class="var">critical</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fget_005fextension_005finfo"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: should contain a <code class="code">gnutls_x509_crl_t</code>  type
</p>
<p><var class="var">indx</var>: Specifies which extension OID to send, use (0) to get the first one.
</p>
<p><var class="var">oid</var>: a pointer to store the OID
</p>
<p><var class="var">sizeof_oid</var>: initially holds the maximum size of  <code class="code">oid</code> , on return
holds actual size of  <code class="code">oid</code> .
</p>
<p><var class="var">critical</var>: output variable with critical flag, may be NULL.
</p>
<p>This function will return the requested extension OID in the CRL,
and the critical flag for it.  The extension OID will be stored as
a string in the provided buffer.  Use
<code class="code">gnutls_x509_crl_get_extension_data()</code>  to extract the data.
</p>
<p>If the buffer provided is not long enough to hold the output, then
* <code class="code">sizeof_oid</code> is updated and <code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  will be
returned.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error code in case of an error.  If your have reached the
last extension available <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> 
will be returned.
</p>
<p><strong class="strong">Since:</strong> 2.8.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fget_005fextension_005foid-1"><span>gnutls_x509_crl_get_extension_oid<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fget_005fextension_005foid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fget_005fextension_005foid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fget_005fextension_005foid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_get_extension_oid</strong> <code class="def-code-arguments">(gnutls_x509_crl_t <var class="var">crl</var>, unsigned <var class="var">indx</var>, void * <var class="var">oid</var>, size_t * <var class="var">sizeof_oid</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fget_005fextension_005foid"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: should contain a <code class="code">gnutls_x509_crl_t</code>  type
</p>
<p><var class="var">indx</var>: Specifies which extension OID to send, use (0) to get the first one.
</p>
<p><var class="var">oid</var>: a pointer to store the OID (may be null)
</p>
<p><var class="var">sizeof_oid</var>: initially holds the size of  <code class="code">oid</code> 
</p>
<p>This function will return the requested extension OID in the CRL.
The extension OID will be stored as a string in the provided
buffer.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error code in case of an error.  If your have reached the
last extension available <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> 
will be returned.
</p>
<p><strong class="strong">Since:</strong> 2.8.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fget_005fissuer_005fdn-1"><span>gnutls_x509_crl_get_issuer_dn<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fget_005fissuer_005fdn-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fget_005fissuer_005fdn"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fget_005fissuer_005fdn"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_get_issuer_dn</strong> <code class="def-code-arguments">(gnutls_x509_crl_t <var class="var">crl</var>, char * <var class="var">buf</var>, size_t * <var class="var">sizeof_buf</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fget_005fissuer_005fdn"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: should contain a gnutls_x509_crl_t type
</p>
<p><var class="var">buf</var>: a pointer to a structure to hold the peer&rsquo;s name (may be null)
</p>
<p><var class="var">sizeof_buf</var>: initially holds the size of  <code class="code">buf</code> 
</p>
<p>This function will copy the name of the CRL issuer in the provided
buffer. The name will be in the form &quot;C=xxxx,O=yyyy,CN=zzzz&quot; as
described in RFC4514. The output string will be ASCII or UTF-8
encoded, depending on the certificate data.
</p>
<p>If buf is <code class="code">NULL</code>  then only the size will be filled.
</p>
<p>This function does not output a fully RFC4514 compliant string, if
that is required see <code class="code">gnutls_x509_crl_get_issuer_dn3()</code> .
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  if the provided buffer is
not long enough, and in that case the sizeof_buf will be updated
with the required size, and 0 on success.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fget_005fissuer_005fdn2-1"><span>gnutls_x509_crl_get_issuer_dn2<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fget_005fissuer_005fdn2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fget_005fissuer_005fdn2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fget_005fissuer_005fdn2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_get_issuer_dn2</strong> <code class="def-code-arguments">(gnutls_x509_crl_t <var class="var">crl</var>, gnutls_datum_t * <var class="var">dn</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fget_005fissuer_005fdn2"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: should contain a <code class="code">gnutls_x509_crl_t</code>  type
</p>
<p><var class="var">dn</var>: a pointer to a structure to hold the name; must be freed using <code class="code">gnutls_free()</code> 
</p>
<p>This function will allocate buffer and copy the name of the CRL issuer.
The name will be in the form &quot;C=xxxx,O=yyyy,CN=zzzz&quot; as
described in RFC4514. The output string will be ASCII or UTF-8
encoded, depending on the certificate data.
</p>
<p>This function does not output a fully RFC4514 compliant string, if
that is required see <code class="code">gnutls_x509_crl_get_issuer_dn3()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.1.10
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fget_005fissuer_005fdn3-1"><span>gnutls_x509_crl_get_issuer_dn3<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fget_005fissuer_005fdn3-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fget_005fissuer_005fdn3"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fget_005fissuer_005fdn3"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_get_issuer_dn3</strong> <code class="def-code-arguments">(gnutls_x509_crl_t <var class="var">crl</var>, gnutls_datum_t * <var class="var">dn</var>, unsigned <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fget_005fissuer_005fdn3"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: should contain a <code class="code">gnutls_x509_crl_t</code>  type
</p>
<p><var class="var">dn</var>: a pointer to a structure to hold the name; must be freed using <code class="code">gnutls_free()</code> 
</p>
<p><var class="var">flags</var>: zero or <code class="code">GNUTLS_X509_DN_FLAG_COMPAT</code> 
</p>
<p>This function will allocate buffer and copy the name of the CRL issuer.
The name will be in the form &quot;C=xxxx,O=yyyy,CN=zzzz&quot; as
described in RFC4514. The output string will be ASCII or UTF-8
encoded, depending on the certificate data.
</p>
<p>When the flag <code class="code">GNUTLS_X509_DN_FLAG_COMPAT</code>  is specified, the output
format will match the format output by previous to 3.5.6 versions of GnuTLS
which was not not fully RFC4514-compliant.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.5.7
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fget_005fissuer_005fdn_005fby_005foid-1"><span>gnutls_x509_crl_get_issuer_dn_by_oid<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fget_005fissuer_005fdn_005fby_005foid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fget_005fissuer_005fdn_005fby_005foid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fget_005fissuer_005fdn_005fby_005foid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_get_issuer_dn_by_oid</strong> <code class="def-code-arguments">(gnutls_x509_crl_t <var class="var">crl</var>, const char * <var class="var">oid</var>, unsigned <var class="var">indx</var>, unsigned int <var class="var">raw_flag</var>, void * <var class="var">buf</var>, size_t * <var class="var">sizeof_buf</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fget_005fissuer_005fdn_005fby_005foid"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: should contain a gnutls_x509_crl_t type
</p>
<p><var class="var">oid</var>: holds an Object Identified in null terminated string
</p>
<p><var class="var">indx</var>: In case multiple same OIDs exist in the RDN, this specifies which to send. Use (0) to get the first one.
</p>
<p><var class="var">raw_flag</var>: If non-zero returns the raw DER data of the DN part.
</p>
<p><var class="var">buf</var>: a pointer to a structure to hold the peer&rsquo;s name (may be null)
</p>
<p><var class="var">sizeof_buf</var>: initially holds the size of  <code class="code">buf</code> 
</p>
<p>This function will extract the part of the name of the CRL issuer
specified by the given OID. The output will be encoded as described
in RFC4514. The output string will be ASCII or UTF-8 encoded,
depending on the certificate data.
</p>
<p>Some helper macros with popular OIDs can be found in gnutls/x509.h
If raw flag is (0), this function will only return known OIDs as
text. Other OIDs will be DER encoded, as described in RFC4514 &ndash; in
hex format with a &rsquo;#&rsquo; prefix.  You can check about known OIDs
using <code class="code">gnutls_x509_dn_oid_known()</code> .
</p>
<p>If buf is null then only the size will be filled.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  if the provided buffer is
not long enough, and in that case the sizeof_buf will be updated
with the required size, and 0 on success.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fget_005fnext_005fupdate-1"><span>gnutls_x509_crl_get_next_update<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fget_005fnext_005fupdate-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fget_005fnext_005fupdate"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fget_005fnext_005fupdate"><span class="category-def">Function: </span><span><code class="def-type">time_t</code> <strong class="def-name">gnutls_x509_crl_get_next_update</strong> <code class="def-code-arguments">(gnutls_x509_crl_t <var class="var">crl</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fget_005fnext_005fupdate"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: should contain a <code class="code">gnutls_x509_crl_t</code>  type
</p>
<p>This function will return the time the next CRL will be issued.
This field is optional in a CRL so it might be normal to get an
error instead.
</p>
<p><strong class="strong">Returns:</strong> when the next CRL will be issued, or (time_t)-1 on error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fget_005fnumber-1"><span>gnutls_x509_crl_get_number<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fget_005fnumber-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fget_005fnumber"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fget_005fnumber"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_get_number</strong> <code class="def-code-arguments">(gnutls_x509_crl_t <var class="var">crl</var>, void * <var class="var">ret</var>, size_t * <var class="var">ret_size</var>, unsigned int * <var class="var">critical</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fget_005fnumber"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: should contain a <code class="code">gnutls_x509_crl_t</code>  type
</p>
<p><var class="var">ret</var>: The place where the number will be copied
</p>
<p><var class="var">ret_size</var>: Holds the size of the result field.
</p>
<p><var class="var">critical</var>: will be non-zero if the extension is marked as critical
(may be null)
</p>
<p>This function will return the CRL number extension.  This is
obtained by the CRL Number extension field (2.5.29.20).
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error code in case of an error.
</p>
<p><strong class="strong">Since:</strong> 2.8.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fget_005fraw_005fissuer_005fdn-1"><span>gnutls_x509_crl_get_raw_issuer_dn<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fget_005fraw_005fissuer_005fdn-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fget_005fraw_005fissuer_005fdn"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fget_005fraw_005fissuer_005fdn"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_get_raw_issuer_dn</strong> <code class="def-code-arguments">(gnutls_x509_crl_t <var class="var">crl</var>, gnutls_datum_t * <var class="var">dn</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fget_005fraw_005fissuer_005fdn"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: should contain a gnutls_x509_crl_t type
</p>
<p><var class="var">dn</var>: will hold the starting point of the DN
</p>
<p>This function will return a pointer to the DER encoded DN structure
and the length.
</p>
<p><strong class="strong">Returns:</strong> a negative error code on error, and (0) on success.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fget_005fsignature-1"><span>gnutls_x509_crl_get_signature<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fget_005fsignature-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fget_005fsignature"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fget_005fsignature"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_get_signature</strong> <code class="def-code-arguments">(gnutls_x509_crl_t <var class="var">crl</var>, char * <var class="var">sig</var>, size_t * <var class="var">sizeof_sig</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fget_005fsignature"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: should contain a gnutls_x509_crl_t type
</p>
<p><var class="var">sig</var>: a pointer where the signature part will be copied (may be null).
</p>
<p><var class="var">sizeof_sig</var>: initially holds the size of  <code class="code">sig</code> 
</p>
<p>This function will extract the signature field of a CRL.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value. 
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fget_005fsignature_005falgorithm-1"><span>gnutls_x509_crl_get_signature_algorithm<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fget_005fsignature_005falgorithm-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fget_005fsignature_005falgorithm"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fget_005fsignature_005falgorithm"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_get_signature_algorithm</strong> <code class="def-code-arguments">(gnutls_x509_crl_t <var class="var">crl</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fget_005fsignature_005falgorithm"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: should contain a <code class="code">gnutls_x509_crl_t</code>  type
</p>
<p>This function will return a value of the <code class="code">gnutls_sign_algorithm_t</code> 
enumeration that is the signature algorithm.
</p>
<p>Since 3.6.0 this function never returns a negative error code.
Error cases and unknown/unsupported signature algorithms are
mapped to <code class="code">GNUTLS_SIGN_UNKNOWN</code> .
</p>
<p><strong class="strong">Returns:</strong> a <code class="code">gnutls_sign_algorithm_t</code>  value
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fget_005fsignature_005foid-1"><span>gnutls_x509_crl_get_signature_oid<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fget_005fsignature_005foid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fget_005fsignature_005foid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fget_005fsignature_005foid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_get_signature_oid</strong> <code class="def-code-arguments">(gnutls_x509_crl_t <var class="var">crl</var>, char * <var class="var">oid</var>, size_t * <var class="var">oid_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fget_005fsignature_005foid"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: should contain a <code class="code">gnutls_x509_crl_t</code>  type
</p>
<p><var class="var">oid</var>: a pointer to a buffer to hold the OID (may be null)
</p>
<p><var class="var">oid_size</var>: initially holds the size of  <code class="code">oid</code> 
</p>
<p>This function will return the OID of the signature algorithm
that has been used to sign this CRL. This is function
is useful in the case <code class="code">gnutls_x509_crl_get_signature_algorithm()</code> 
returned <code class="code">GNUTLS_SIGN_UNKNOWN</code> .
</p>
<p><strong class="strong">Returns:</strong> zero or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 3.5.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fget_005fthis_005fupdate-1"><span>gnutls_x509_crl_get_this_update<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fget_005fthis_005fupdate-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fget_005fthis_005fupdate"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fget_005fthis_005fupdate"><span class="category-def">Function: </span><span><code class="def-type">time_t</code> <strong class="def-name">gnutls_x509_crl_get_this_update</strong> <code class="def-code-arguments">(gnutls_x509_crl_t <var class="var">crl</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fget_005fthis_005fupdate"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: should contain a <code class="code">gnutls_x509_crl_t</code>  type
</p>
<p>This function will return the time this CRL was issued.
</p>
<p><strong class="strong">Returns:</strong> when the CRL was issued, or (time_t)-1 on error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fget_005fversion-1"><span>gnutls_x509_crl_get_version<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fget_005fversion-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fget_005fversion"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fget_005fversion"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_get_version</strong> <code class="def-code-arguments">(gnutls_x509_crl_t <var class="var">crl</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fget_005fversion"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: should contain a <code class="code">gnutls_x509_crl_t</code>  type
</p>
<p>This function will return the version of the specified CRL.
</p>
<p><strong class="strong">Returns:</strong> The version number, or a negative error code on error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fimport-1"><span>gnutls_x509_crl_import<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fimport-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fimport"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fimport"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_import</strong> <code class="def-code-arguments">(gnutls_x509_crl_t <var class="var">crl</var>, const gnutls_datum_t * <var class="var">data</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fimport"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: The data to store the parsed CRL.
</p>
<p><var class="var">data</var>: The DER or PEM encoded CRL.
</p>
<p><var class="var">format</var>: One of DER or PEM
</p>
<p>This function will convert the given DER or PEM encoded CRL
to the native <code class="code">gnutls_x509_crl_t</code>  format. The output will be stored in &rsquo;crl&rsquo;.
</p>
<p>If the CRL is PEM encoded it should have a header of &quot;X509 CRL&quot;.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005finit-1"><span>gnutls_x509_crl_init<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005finit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005finit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005finit"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_init</strong> <code class="def-code-arguments">(gnutls_x509_crl_t * <var class="var">crl</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005finit"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: A pointer to the type to be initialized
</p>
<p>This function will initialize a CRL structure. CRL stands for
Certificate Revocation List. A revocation list usually contains
lists of certificate serial numbers that have been revoked by an
Authority. The revocation lists are always signed with the
authority&rsquo;s private key.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fiter_005fcrt_005fserial-1"><span>gnutls_x509_crl_iter_crt_serial<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fiter_005fcrt_005fserial-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fiter_005fcrt_005fserial"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fiter_005fcrt_005fserial"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_iter_crt_serial</strong> <code class="def-code-arguments">(gnutls_x509_crl_t <var class="var">crl</var>, gnutls_x509_crl_iter_t * <var class="var">iter</var>, unsigned char * <var class="var">serial</var>, size_t * <var class="var">serial_size</var>, time_t * <var class="var">t</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fiter_005fcrt_005fserial"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: should contain a <code class="code">gnutls_x509_crl_t</code>  type
</p>
<p><var class="var">iter</var>: A pointer to an iterator (initially the iterator should be <code class="code">NULL</code> )
</p>
<p><var class="var">serial</var>: where the serial number will be copied
</p>
<p><var class="var">serial_size</var>: initially holds the size of serial
</p>
<p><var class="var">t</var>: if non null, will hold the time this certificate was revoked
</p>
<p>This function performs the same as <code class="code">gnutls_x509_crl_get_crt_serial()</code> ,
but reads sequentially and keeps state in the iterator 
between calls. That allows it to provide better performance in sequences 
with many elements (50000+).
</p>
<p>When past the last element is accessed <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> 
is returned and the iterator is reset.
</p>
<p>After use, the iterator must be deinitialized using <code class="code">gnutls_x509_crl_iter_deinit()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fiter_005fdeinit-1"><span>gnutls_x509_crl_iter_deinit<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fiter_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fiter_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fiter_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_x509_crl_iter_deinit</strong> <code class="def-code-arguments">(gnutls_x509_crl_iter_t <var class="var">iter</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fiter_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">iter</var>: The iterator to be deinitialized
</p>
<p>This function will deinitialize an iterator type.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005flist_005fimport-1"><span>gnutls_x509_crl_list_import<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005flist_005fimport-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005flist_005fimport"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005flist_005fimport"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_list_import</strong> <code class="def-code-arguments">(gnutls_x509_crl_t * <var class="var">crls</var>, unsigned int * <var class="var">crl_max</var>, const gnutls_datum_t * <var class="var">data</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005flist_005fimport"> &para;</a></span></dt>
<dd><p><var class="var">crls</var>: Indicates where the parsed CRLs will be copied to. Must not be initialized.
</p>
<p><var class="var">crl_max</var>: Initially must hold the maximum number of crls. It will be updated with the number of crls available.
</p>
<p><var class="var">data</var>: The CRL data
</p>
<p><var class="var">format</var>: One of DER or PEM.
</p>
<p><var class="var">flags</var>: must be (0) or an OR&rsquo;d sequence of gnutls_certificate_import_flags.
</p>
<p>This function will convert the given CRL list
to the native gnutls_x509_crl_t format. The output will be stored
in  <code class="code">crls</code> .  They will be automatically initialized.
</p>
<p>If the Certificate is PEM encoded it should have a header of &quot;X509 CRL&quot;.
</p>
<p><strong class="strong">Returns:</strong> the number of certificates read or a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005flist_005fimport2-1"><span>gnutls_x509_crl_list_import2<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005flist_005fimport2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005flist_005fimport2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005flist_005fimport2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_list_import2</strong> <code class="def-code-arguments">(gnutls_x509_crl_t ** <var class="var">crls</var>, unsigned int * <var class="var">size</var>, const gnutls_datum_t * <var class="var">data</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005flist_005fimport2"> &para;</a></span></dt>
<dd><p><var class="var">crls</var>: Will contain the parsed crl list.
</p>
<p><var class="var">size</var>: It will contain the size of the list.
</p>
<p><var class="var">data</var>: The CRL data.
</p>
<p><var class="var">format</var>: One of DER or PEM.
</p>
<p><var class="var">flags</var>: must be (0) or an OR&rsquo;d sequence of gnutls_certificate_import_flags.
</p>
<p>This function will convert the given CRL list
to the native gnutls_x509_crl_t format. The output will be stored
in  <code class="code">crls</code> .  They will be automatically initialized.
</p>
<p>If the Certificate is PEM encoded it should have a header of &quot;X509
CRL&quot;.
</p>
<p><strong class="strong">Returns:</strong> the number of certificates read or a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fprint-1"><span>gnutls_x509_crl_print<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fprint-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fprint"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fprint"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_print</strong> <code class="def-code-arguments">(gnutls_x509_crl_t <var class="var">crl</var>, gnutls_certificate_print_formats_t <var class="var">format</var>, gnutls_datum_t * <var class="var">out</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fprint"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: The data to be printed
</p>
<p><var class="var">format</var>: Indicate the format to use
</p>
<p><var class="var">out</var>: Newly allocated datum with null terminated string.
</p>
<p>This function will pretty print a X.509 certificate revocation
list, suitable for display to a human.
</p>
<p>The output  <code class="code">out</code> needs to be deallocated using <code class="code">gnutls_free()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fset_005fauthority_005fkey_005fid-1"><span>gnutls_x509_crl_set_authority_key_id<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fset_005fauthority_005fkey_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fset_005fauthority_005fkey_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fset_005fauthority_005fkey_005fid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_set_authority_key_id</strong> <code class="def-code-arguments">(gnutls_x509_crl_t <var class="var">crl</var>, const void * <var class="var">id</var>, size_t <var class="var">id_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fset_005fauthority_005fkey_005fid"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: a CRL of type <code class="code">gnutls_x509_crl_t</code> 
</p>
<p><var class="var">id</var>: The key ID
</p>
<p><var class="var">id_size</var>: Holds the size of the serial field.
</p>
<p>This function will set the CRL&rsquo;s authority key ID extension.  Only
the keyIdentifier field can be set with this function. This may
be used by an authority that holds multiple private keys, to distinguish
the used key.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.8.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fset_005fcrt-1"><span>gnutls_x509_crl_set_crt<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fset_005fcrt-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fset_005fcrt"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fset_005fcrt"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_set_crt</strong> <code class="def-code-arguments">(gnutls_x509_crl_t <var class="var">crl</var>, gnutls_x509_crt_t <var class="var">crt</var>, time_t <var class="var">revocation_time</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fset_005fcrt"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: should contain a gnutls_x509_crl_t type
</p>
<p><var class="var">crt</var>: a certificate of type <code class="code">gnutls_x509_crt_t</code>  with the revoked certificate
</p>
<p><var class="var">revocation_time</var>: The time this certificate was revoked
</p>
<p>This function will set a revoked certificate&rsquo;s serial number to the CRL.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fset_005fcrt_005fserial-1"><span>gnutls_x509_crl_set_crt_serial<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fset_005fcrt_005fserial-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fset_005fcrt_005fserial"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fset_005fcrt_005fserial"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_set_crt_serial</strong> <code class="def-code-arguments">(gnutls_x509_crl_t <var class="var">crl</var>, const void * <var class="var">serial</var>, size_t <var class="var">serial_size</var>, time_t <var class="var">revocation_time</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fset_005fcrt_005fserial"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: should contain a gnutls_x509_crl_t type
</p>
<p><var class="var">serial</var>: The revoked certificate&rsquo;s serial number
</p>
<p><var class="var">serial_size</var>: Holds the size of the serial field.
</p>
<p><var class="var">revocation_time</var>: The time this certificate was revoked
</p>
<p>This function will set a revoked certificate&rsquo;s serial number to the CRL.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fset_005fnext_005fupdate-1"><span>gnutls_x509_crl_set_next_update<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fset_005fnext_005fupdate-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fset_005fnext_005fupdate"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fset_005fnext_005fupdate"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_set_next_update</strong> <code class="def-code-arguments">(gnutls_x509_crl_t <var class="var">crl</var>, time_t <var class="var">exp_time</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fset_005fnext_005fupdate"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: should contain a gnutls_x509_crl_t type
</p>
<p><var class="var">exp_time</var>: The actual time
</p>
<p>This function will set the time this CRL will be updated.
This is an optional value to be set on a CRL and this call
can be omitted when generating a CRL.
</p>
<p>Prior to GnuTLS 3.5.7, setting a nextUpdate field was required
in order to generate a CRL.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fset_005fnumber-1"><span>gnutls_x509_crl_set_number<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fset_005fnumber-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fset_005fnumber"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fset_005fnumber"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_set_number</strong> <code class="def-code-arguments">(gnutls_x509_crl_t <var class="var">crl</var>, const void * <var class="var">nr</var>, size_t <var class="var">nr_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fset_005fnumber"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: a CRL of type <code class="code">gnutls_x509_crl_t</code> 
</p>
<p><var class="var">nr</var>: The CRL number
</p>
<p><var class="var">nr_size</var>: Holds the size of the nr field.
</p>
<p>This function will set the CRL&rsquo;s number extension. This
is to be used as a unique and monotonic number assigned to
the CRL by the authority.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.8.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fset_005fthis_005fupdate-1"><span>gnutls_x509_crl_set_this_update<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fset_005fthis_005fupdate-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fset_005fthis_005fupdate"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fset_005fthis_005fupdate"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_set_this_update</strong> <code class="def-code-arguments">(gnutls_x509_crl_t <var class="var">crl</var>, time_t <var class="var">act_time</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fset_005fthis_005fupdate"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: should contain a gnutls_x509_crl_t type
</p>
<p><var class="var">act_time</var>: The actual time
</p>
<p>This function will set the time this CRL was issued.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fset_005fversion-1"><span>gnutls_x509_crl_set_version<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fset_005fversion-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fset_005fversion"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fset_005fversion"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_set_version</strong> <code class="def-code-arguments">(gnutls_x509_crl_t <var class="var">crl</var>, unsigned int <var class="var">version</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fset_005fversion"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: should contain a gnutls_x509_crl_t type
</p>
<p><var class="var">version</var>: holds the version number. For CRLv1 crls must be 1.
</p>
<p>This function will set the version of the CRL. This
must be one for CRL version 1, and so on. The CRLs generated
by gnutls should have a version number of 2.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fsign-1"><span>gnutls_x509_crl_sign<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fsign-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fsign"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fsign"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_sign</strong> <code class="def-code-arguments">(gnutls_x509_crl_t <var class="var">crl</var>, gnutls_x509_crt_t <var class="var">issuer</var>, gnutls_x509_privkey_t <var class="var">issuer_key</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fsign"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: should contain a gnutls_x509_crl_t type
</p>
<p><var class="var">issuer</var>: is the certificate of the certificate issuer
</p>
<p><var class="var">issuer_key</var>: holds the issuer&rsquo;s private key
</p>
<p>This function is the same a <code class="code">gnutls_x509_crl_sign2()</code>  with no flags,
and an appropriate hash algorithm. The hash algorithm used may
vary between versions of GnuTLS, and it is tied to the security
level of the issuer&rsquo;s public key.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fsign2-1"><span>gnutls_x509_crl_sign2<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fsign2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fsign2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fsign2-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_sign2</strong> <code class="def-code-arguments">(gnutls_x509_crl_t <var class="var">crl</var>, gnutls_x509_crt_t <var class="var">issuer</var>, gnutls_x509_privkey_t <var class="var">issuer_key</var>, gnutls_digest_algorithm_t <var class="var">dig</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fsign2-1"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: should contain a gnutls_x509_crl_t type
</p>
<p><var class="var">issuer</var>: is the certificate of the certificate issuer
</p>
<p><var class="var">issuer_key</var>: holds the issuer&rsquo;s private key
</p>
<p><var class="var">dig</var>: The message digest to use. GNUTLS_DIG_SHA256 is the safe choice unless you know what you&rsquo;re doing.
</p>
<p><var class="var">flags</var>: must be 0
</p>
<p>This function will sign the CRL with the issuer&rsquo;s private key, and
will copy the issuer&rsquo;s information into the CRL.
</p>
<p>This must be the last step in a certificate CRL since all
the previously set parameters are now signed.
</p>
<p>A known limitation of this function is, that a newly-signed CRL will not
be fully functional (e.g., for signature verification), until it
is exported an re-imported.
</p>
<p>After GnuTLS 3.6.1 the value of  <code class="code">dig</code> may be <code class="code">GNUTLS_DIG_UNKNOWN</code> ,
and in that case, a suitable but reasonable for the key algorithm will be selected.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fverify-1"><span>gnutls_x509_crl_verify<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fverify-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fverify"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fverify"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_verify</strong> <code class="def-code-arguments">(gnutls_x509_crl_t <var class="var">crl</var>, const gnutls_x509_crt_t * <var class="var">trusted_cas</var>, unsigned <var class="var">tcas_size</var>, unsigned int <var class="var">flags</var>, unsigned int * <var class="var">verify</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fverify"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: is the crl to be verified
</p>
<p><var class="var">trusted_cas</var>: is a certificate list that is considered to be trusted one
</p>
<p><var class="var">tcas_size</var>: holds the number of CA certificates in CA_list
</p>
<p><var class="var">flags</var>: Flags that may be used to change the verification algorithm. Use OR of the gnutls_certificate_verify_flags enumerations.
</p>
<p><var class="var">verify</var>: will hold the crl verification output.
</p>
<p>This function will try to verify the given crl and return its verification status.
See <code class="code">gnutls_x509_crt_list_verify()</code>  for a detailed description of
return values. Note that since GnuTLS 3.1.4 this function includes
the time checks.
</p>
<p>Note that value in  <code class="code">verify</code> is set only when the return value of this 
function is success (i.e, failure to trust a CRL a certificate does not imply 
a negative return value).
</p>
<p>Before GnuTLS 3.5.7 this function would return zero or a positive
number on success.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0), otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fdeinit-1"><span>gnutls_x509_crq_deinit<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_x509_crq_deinit</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: the type to be deinitialized
</p>
<p>This function will deinitialize a PKCS<code class="code">10</code>  certificate request
structure.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fexport-1"><span>gnutls_x509_crq_export<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fexport-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fexport"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fexport"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_export</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, void * <var class="var">output_data</var>, size_t * <var class="var">output_data_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fexport"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: should contain a <code class="code">gnutls_x509_crq_t</code>  type
</p>
<p><var class="var">format</var>: the format of output params. One of PEM or DER.
</p>
<p><var class="var">output_data</var>: will contain a certificate request PEM or DER encoded
</p>
<p><var class="var">output_data_size</var>: holds the size of output_data (and will be
replaced by the actual size of parameters)
</p>
<p>This function will export the certificate request to a PEM or DER
encoded PKCS10 structure.
</p>
<p>If the buffer provided is not long enough to hold the output, then
<code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  will be returned and
* <code class="code">output_data_size</code> will be updated.
</p>
<p>If the structure is PEM encoded, it will have a header of &quot;BEGIN
NEW CERTIFICATE REQUEST&quot;.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fexport2-1"><span>gnutls_x509_crq_export2<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fexport2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fexport2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fexport2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_export2</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, gnutls_datum_t * <var class="var">out</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fexport2"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: should contain a <code class="code">gnutls_x509_crq_t</code>  type
</p>
<p><var class="var">format</var>: the format of output params. One of PEM or DER.
</p>
<p><var class="var">out</var>: will contain a certificate request PEM or DER encoded
</p>
<p>This function will export the certificate request to a PEM or DER
encoded PKCS10 structure.
</p>
<p>The output buffer is allocated using <code class="code">gnutls_malloc()</code> .
</p>
<p>If the structure is PEM encoded, it will have a header of &quot;BEGIN
NEW CERTIFICATE REQUEST&quot;.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p>Since 3.1.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fget_005fattribute_005fby_005foid-1"><span>gnutls_x509_crq_get_attribute_by_oid<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fget_005fattribute_005fby_005foid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fget_005fattribute_005fby_005foid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fget_005fattribute_005fby_005foid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_get_attribute_by_oid</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, const char * <var class="var">oid</var>, unsigned <var class="var">indx</var>, void * <var class="var">buf</var>, size_t * <var class="var">buf_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fget_005fattribute_005fby_005foid"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: should contain a <code class="code">gnutls_x509_crq_t</code>  type
</p>
<p><var class="var">oid</var>: holds an Object Identifier in null-terminated string
</p>
<p><var class="var">indx</var>: In case multiple same OIDs exist in the attribute list, this
specifies which to get, use (0) to get the first one
</p>
<p><var class="var">buf</var>: a pointer to a structure to hold the attribute data (may be <code class="code">NULL</code> )
</p>
<p><var class="var">buf_size</var>: initially holds the size of  <code class="code">buf</code> 
</p>
<p>This function will return the attribute in the certificate request
specified by the given Object ID.  The attribute will be DER
encoded.
</p>
<p>Attributes in a certificate request is an optional set of data
appended to the request. Their interpretation depends on the CA policy.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fget_005fattribute_005fdata-1"><span>gnutls_x509_crq_get_attribute_data<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fget_005fattribute_005fdata-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fget_005fattribute_005fdata"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fget_005fattribute_005fdata"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_get_attribute_data</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, unsigned <var class="var">indx</var>, void * <var class="var">data</var>, size_t * <var class="var">sizeof_data</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fget_005fattribute_005fdata"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: should contain a <code class="code">gnutls_x509_crq_t</code>  type
</p>
<p><var class="var">indx</var>: Specifies which attribute number to get. Use (0) to get the first one.
</p>
<p><var class="var">data</var>: a pointer to a structure to hold the data (may be null)
</p>
<p><var class="var">sizeof_data</var>: initially holds the size of  <code class="code">oid</code> 
</p>
<p>This function will return the requested attribute data in the
certificate request.  The attribute data will be stored as a string in the
provided buffer.
</p>
<p>Use <code class="code">gnutls_x509_crq_get_attribute_info()</code>  to extract the OID.
Use <code class="code">gnutls_x509_crq_get_attribute_by_oid()</code>  instead,
if you want to get data indexed by the attribute OID rather than
sequence.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error code in case of an error.  If your have reached the
last extension available <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> 
will be returned.
</p>
<p><strong class="strong">Since:</strong> 2.8.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fget_005fattribute_005finfo-1"><span>gnutls_x509_crq_get_attribute_info<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fget_005fattribute_005finfo-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fget_005fattribute_005finfo"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fget_005fattribute_005finfo"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_get_attribute_info</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, unsigned <var class="var">indx</var>, void * <var class="var">oid</var>, size_t * <var class="var">sizeof_oid</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fget_005fattribute_005finfo"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: should contain a <code class="code">gnutls_x509_crq_t</code>  type
</p>
<p><var class="var">indx</var>: Specifies which attribute number to get. Use (0) to get the first one.
</p>
<p><var class="var">oid</var>: a pointer to a structure to hold the OID
</p>
<p><var class="var">sizeof_oid</var>: initially holds the maximum size of  <code class="code">oid</code> , on return
holds actual size of  <code class="code">oid</code> .
</p>
<p>This function will return the requested attribute OID in the
certificate, and the critical flag for it.  The attribute OID will
be stored as a string in the provided buffer.  Use
<code class="code">gnutls_x509_crq_get_attribute_data()</code>  to extract the data.
</p>
<p>If the buffer provided is not long enough to hold the output, then
* <code class="code">sizeof_oid</code> is updated and <code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  will be
returned.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error code in case of an error.  If your have reached the
last extension available <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> 
will be returned.
</p>
<p><strong class="strong">Since:</strong> 2.8.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fget_005fbasic_005fconstraints-1"><span>gnutls_x509_crq_get_basic_constraints<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fget_005fbasic_005fconstraints-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fget_005fbasic_005fconstraints"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fget_005fbasic_005fconstraints"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_get_basic_constraints</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, unsigned int * <var class="var">critical</var>, unsigned int * <var class="var">ca</var>, int * <var class="var">pathlen</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fget_005fbasic_005fconstraints"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: should contain a <code class="code">gnutls_x509_crq_t</code>  type
</p>
<p><var class="var">critical</var>: will be non-zero if the extension is marked as critical
</p>
<p><var class="var">ca</var>: pointer to output integer indicating CA status, may be NULL,
value is 1 if the certificate CA flag is set, 0 otherwise.
</p>
<p><var class="var">pathlen</var>: pointer to output integer indicating path length (may be
NULL), non-negative error codes indicate a present pathLenConstraint
field and the actual value, -1 indicate that the field is absent.
</p>
<p>This function will read the certificate&rsquo;s basic constraints, and
return the certificates CA status.  It reads the basicConstraints
X.509 extension (2.5.29.19).
</p>
<p><strong class="strong">Returns:</strong> If the certificate is a CA a positive value will be
returned, or (0) if the certificate does not have CA flag set.
A negative error code may be returned in case of errors.  If the
certificate does not contain the basicConstraints extension
<code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  will be returned.
</p>
<p><strong class="strong">Since:</strong> 2.8.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fget_005fchallenge_005fpassword-1"><span>gnutls_x509_crq_get_challenge_password<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fget_005fchallenge_005fpassword-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fget_005fchallenge_005fpassword"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fget_005fchallenge_005fpassword"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_get_challenge_password</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, char * <var class="var">pass</var>, size_t * <var class="var">pass_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fget_005fchallenge_005fpassword"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: should contain a <code class="code">gnutls_x509_crq_t</code>  type
</p>
<p><var class="var">pass</var>: will hold a (0)-terminated password string
</p>
<p><var class="var">pass_size</var>: Initially holds the size of  <code class="code">pass</code> .
</p>
<p>This function will return the challenge password in the request.
The challenge password is intended to be used for requesting a
revocation of the certificate.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fget_005fdn-1"><span>gnutls_x509_crq_get_dn<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fget_005fdn-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fget_005fdn"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fget_005fdn"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_get_dn</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, char * <var class="var">buf</var>, size_t * <var class="var">buf_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fget_005fdn"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: should contain a <code class="code">gnutls_x509_crq_t</code>  type
</p>
<p><var class="var">buf</var>: a pointer to a structure to hold the name (may be <code class="code">NULL</code> )
</p>
<p><var class="var">buf_size</var>: initially holds the size of  <code class="code">buf</code> 
</p>
<p>This function will copy the name of the Certificate request subject
to the provided buffer.  The name will be in the form
&quot;C=xxxx,O=yyyy,CN=zzzz&quot; as described in RFC 2253. The output string
 <code class="code">buf</code> will be ASCII or UTF-8 encoded, depending on the certificate
data.
</p>
<p>This function does not output a fully RFC4514 compliant string, if
that is required see <code class="code">gnutls_x509_crq_get_dn3()</code> .
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  if the provided buffer is not
long enough, and in that case the * <code class="code">buf_size</code> will be updated with
the required size.  On success 0 is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fget_005fdn2-1"><span>gnutls_x509_crq_get_dn2<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fget_005fdn2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fget_005fdn2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fget_005fdn2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_get_dn2</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, gnutls_datum_t * <var class="var">dn</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fget_005fdn2"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: should contain a <code class="code">gnutls_x509_crq_t</code>  type
</p>
<p><var class="var">dn</var>: a pointer to a structure to hold the name; must be freed using <code class="code">gnutls_free()</code> 
</p>
<p>This function will allocate buffer and copy the name of the Certificate 
request. The name will be in the form &quot;C=xxxx,O=yyyy,CN=zzzz&quot; as
described in RFC4514. The output string will be ASCII or UTF-8
encoded, depending on the certificate data.
</p>
<p>This function does not output a fully RFC4514 compliant string, if
that is required see <code class="code">gnutls_x509_crq_get_dn3()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value. and a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 3.1.10
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fget_005fdn3-1"><span>gnutls_x509_crq_get_dn3<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fget_005fdn3-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fget_005fdn3"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fget_005fdn3"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_get_dn3</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, gnutls_datum_t * <var class="var">dn</var>, unsigned <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fget_005fdn3"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: should contain a <code class="code">gnutls_x509_crq_t</code>  type
</p>
<p><var class="var">dn</var>: a pointer to a structure to hold the name; must be freed using <code class="code">gnutls_free()</code> 
</p>
<p><var class="var">flags</var>: zero or <code class="code">GNUTLS_X509_DN_FLAG_COMPAT</code> 
</p>
<p>This function will allocate buffer and copy the name of the Certificate 
request. The name will be in the form &quot;C=xxxx,O=yyyy,CN=zzzz&quot; as
described in RFC4514. The output string will be ASCII or UTF-8
encoded, depending on the certificate data.
</p>
<p>When the flag <code class="code">GNUTLS_X509_DN_FLAG_COMPAT</code>  is specified, the output
format will match the format output by previous to 3.5.6 versions of GnuTLS
which was not not fully RFC4514-compliant.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value. and a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 3.5.7
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fget_005fdn_005fby_005foid-1"><span>gnutls_x509_crq_get_dn_by_oid<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fget_005fdn_005fby_005foid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fget_005fdn_005fby_005foid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fget_005fdn_005fby_005foid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_get_dn_by_oid</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, const char * <var class="var">oid</var>, unsigned <var class="var">indx</var>, unsigned int <var class="var">raw_flag</var>, void * <var class="var">buf</var>, size_t * <var class="var">buf_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fget_005fdn_005fby_005foid"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: should contain a gnutls_x509_crq_t type
</p>
<p><var class="var">oid</var>: holds an Object Identifier in a null terminated string
</p>
<p><var class="var">indx</var>: In case multiple same OIDs exist in the RDN, this specifies
which to get. Use (0) to get the first one.
</p>
<p><var class="var">raw_flag</var>: If non-zero returns the raw DER data of the DN part.
</p>
<p><var class="var">buf</var>: a pointer to a structure to hold the name (may be <code class="code">NULL</code> )
</p>
<p><var class="var">buf_size</var>: initially holds the size of  <code class="code">buf</code> 
</p>
<p>This function will extract the part of the name of the Certificate
request subject, specified by the given OID. The output will be
encoded as described in RFC2253. The output string will be ASCII
or UTF-8 encoded, depending on the certificate data.
</p>
<p>Some helper macros with popular OIDs can be found in gnutls/x509.h
If raw flag is (0), this function will only return known OIDs as
text. Other OIDs will be DER encoded, as described in RFC2253 &ndash;
in hex format with a &rsquo;\#&rsquo; prefix.  You can check about known OIDs
using <code class="code">gnutls_x509_dn_oid_known()</code> .
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  if the provided buffer is
not long enough, and in that case the * <code class="code">buf_size</code> will be
updated with the required size.  On success 0 is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fget_005fdn_005foid-1"><span>gnutls_x509_crq_get_dn_oid<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fget_005fdn_005foid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fget_005fdn_005foid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fget_005fdn_005foid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_get_dn_oid</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, unsigned <var class="var">indx</var>, void * <var class="var">oid</var>, size_t * <var class="var">sizeof_oid</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fget_005fdn_005foid"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: should contain a gnutls_x509_crq_t type
</p>
<p><var class="var">indx</var>: Specifies which DN OID to get. Use (0) to get the first one.
</p>
<p><var class="var">oid</var>: a pointer to a structure to hold the name (may be <code class="code">NULL</code> )
</p>
<p><var class="var">sizeof_oid</var>: initially holds the size of  <code class="code">oid</code> 
</p>
<p>This function will extract the requested OID of the name of the
certificate request subject, specified by the given index.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  if the provided buffer is
not long enough, and in that case the * <code class="code">sizeof_oid</code> will be
updated with the required size.  On success 0 is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fget_005fextension_005fby_005foid-1"><span>gnutls_x509_crq_get_extension_by_oid<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fget_005fextension_005fby_005foid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fget_005fextension_005fby_005foid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fget_005fextension_005fby_005foid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_get_extension_by_oid</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, const char * <var class="var">oid</var>, unsigned <var class="var">indx</var>, void * <var class="var">buf</var>, size_t * <var class="var">buf_size</var>, unsigned int * <var class="var">critical</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fget_005fextension_005fby_005foid"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: should contain a <code class="code">gnutls_x509_crq_t</code>  type
</p>
<p><var class="var">oid</var>: holds an Object Identifier in a null terminated string
</p>
<p><var class="var">indx</var>: In case multiple same OIDs exist in the extensions, this
specifies which to get. Use (0) to get the first one.
</p>
<p><var class="var">buf</var>: a pointer to a structure to hold the name (may be null)
</p>
<p><var class="var">buf_size</var>: initially holds the size of  <code class="code">buf</code> 
</p>
<p><var class="var">critical</var>: will be non-zero if the extension is marked as critical
</p>
<p>This function will return the extension specified by the OID in
the certificate.  The extensions will be returned as binary data
DER encoded, in the provided buffer.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error code in case of an error.  If the certificate does not
contain the specified extension
<code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  will be returned.
</p>
<p><strong class="strong">Since:</strong> 2.8.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fget_005fextension_005fby_005foid2-1"><span>gnutls_x509_crq_get_extension_by_oid2<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fget_005fextension_005fby_005foid2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fget_005fextension_005fby_005foid2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fget_005fextension_005fby_005foid2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_get_extension_by_oid2</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, const char * <var class="var">oid</var>, unsigned <var class="var">indx</var>, gnutls_datum_t * <var class="var">output</var>, unsigned int * <var class="var">critical</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fget_005fextension_005fby_005foid2"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: should contain a <code class="code">gnutls_x509_crq_t</code>  type
</p>
<p><var class="var">oid</var>: holds an Object Identifier in a null terminated string
</p>
<p><var class="var">indx</var>: In case multiple same OIDs exist in the extensions, this
specifies which to get. Use (0) to get the first one.
</p>
<p><var class="var">output</var>: will hold the allocated extension data
</p>
<p><var class="var">critical</var>: will be non-zero if the extension is marked as critical
</p>
<p>This function will return the extension specified by the OID in
the certificate.  The extensions will be returned as binary data
DER encoded, in the provided buffer.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error code in case of an error.  If the certificate does not
contain the specified extension
<code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  will be returned.
</p>
<p><strong class="strong">Since:</strong> 3.3.8
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fget_005fextension_005fdata-1"><span>gnutls_x509_crq_get_extension_data<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fget_005fextension_005fdata-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fget_005fextension_005fdata"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fget_005fextension_005fdata"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_get_extension_data</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, unsigned <var class="var">indx</var>, void * <var class="var">data</var>, size_t * <var class="var">sizeof_data</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fget_005fextension_005fdata"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: should contain a <code class="code">gnutls_x509_crq_t</code>  type
</p>
<p><var class="var">indx</var>: Specifies which extension number to get. Use (0) to get the first one.
</p>
<p><var class="var">data</var>: a pointer to a structure to hold the data (may be null)
</p>
<p><var class="var">sizeof_data</var>: initially holds the size of  <code class="code">oid</code> 
</p>
<p>This function will return the requested extension data in the
certificate.  The extension data will be stored as a string in the
provided buffer.
</p>
<p>Use <code class="code">gnutls_x509_crq_get_extension_info()</code>  to extract the OID and
critical flag.  Use <code class="code">gnutls_x509_crq_get_extension_by_oid()</code>  instead,
if you want to get data indexed by the extension OID rather than
sequence.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error code in case of an error.  If your have reached the
last extension available <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> 
will be returned.
</p>
<p><strong class="strong">Since:</strong> 2.8.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fget_005fextension_005fdata2-1"><span>gnutls_x509_crq_get_extension_data2<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fget_005fextension_005fdata2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fget_005fextension_005fdata2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fget_005fextension_005fdata2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_get_extension_data2</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, unsigned <var class="var">indx</var>, gnutls_datum_t * <var class="var">data</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fget_005fextension_005fdata2"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: should contain a <code class="code">gnutls_x509_crq_t</code>  type
</p>
<p><var class="var">indx</var>: Specifies which extension OID to read. Use (0) to get the first one.
</p>
<p><var class="var">data</var>: will contain the extension DER-encoded data
</p>
<p>This function will return the requested extension data in the
certificate request.  The extension data will be allocated using
<code class="code">gnutls_malloc()</code> .
</p>
<p>Use <code class="code">gnutls_x509_crq_get_extension_info()</code>  to extract the OID.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned.  If you have reached the
last extension available <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> 
will be returned.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fget_005fextension_005finfo-1"><span>gnutls_x509_crq_get_extension_info<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fget_005fextension_005finfo-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fget_005fextension_005finfo"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fget_005fextension_005finfo"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_get_extension_info</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, unsigned <var class="var">indx</var>, void * <var class="var">oid</var>, size_t * <var class="var">sizeof_oid</var>, unsigned int * <var class="var">critical</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fget_005fextension_005finfo"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: should contain a <code class="code">gnutls_x509_crq_t</code>  type
</p>
<p><var class="var">indx</var>: Specifies which extension number to get. Use (0) to get the first one.
</p>
<p><var class="var">oid</var>: a pointer to store the OID
</p>
<p><var class="var">sizeof_oid</var>: initially holds the maximum size of  <code class="code">oid</code> , on return
holds actual size of  <code class="code">oid</code> .
</p>
<p><var class="var">critical</var>: output variable with critical flag, may be NULL.
</p>
<p>This function will return the requested extension OID in the
certificate, and the critical flag for it.  The extension OID will
be stored as a string in the provided buffer.  Use
<code class="code">gnutls_x509_crq_get_extension_data()</code>  to extract the data.
</p>
<p>If the buffer provided is not long enough to hold the output, then
* <code class="code">sizeof_oid</code> is updated and <code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  will be
returned.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error code in case of an error.  If your have reached the
last extension available <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> 
will be returned.
</p>
<p><strong class="strong">Since:</strong> 2.8.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fget_005fkey_005fid-1"><span>gnutls_x509_crq_get_key_id<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fget_005fkey_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fget_005fkey_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fget_005fkey_005fid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_get_key_id</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, unsigned int <var class="var">flags</var>, unsigned char * <var class="var">output_data</var>, size_t * <var class="var">output_data_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fget_005fkey_005fid"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: a certificate of type <code class="code">gnutls_x509_crq_t</code> 
</p>
<p><var class="var">flags</var>: should be one of the flags from <code class="code">gnutls_keyid_flags_t</code> 
</p>
<p><var class="var">output_data</var>: will contain the key ID
</p>
<p><var class="var">output_data_size</var>: holds the size of output_data (and will be
replaced by the actual size of parameters)
</p>
<p>This function will return a unique ID that depends on the public key
parameters.  This ID can be used in checking whether a certificate
corresponds to the given private key.
</p>
<p>If the buffer provided is not long enough to hold the output, then
* <code class="code">output_data_size</code> is updated and GNUTLS_E_SHORT_MEMORY_BUFFER will
be returned.  The output will normally be a SHA-1 hash output,
which is 20 bytes.
</p>
<p><strong class="strong">Returns:</strong> In case of failure a negative error code will be
returned, and 0 on success.
</p>
<p><strong class="strong">Since:</strong> 2.8.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fget_005fkey_005fpurpose_005foid-1"><span>gnutls_x509_crq_get_key_purpose_oid<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fget_005fkey_005fpurpose_005foid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fget_005fkey_005fpurpose_005foid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fget_005fkey_005fpurpose_005foid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_get_key_purpose_oid</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, unsigned <var class="var">indx</var>, void * <var class="var">oid</var>, size_t * <var class="var">sizeof_oid</var>, unsigned int * <var class="var">critical</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fget_005fkey_005fpurpose_005foid"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: should contain a <code class="code">gnutls_x509_crq_t</code>  type
</p>
<p><var class="var">indx</var>: This specifies which OID to return, use (0) to get the first one
</p>
<p><var class="var">oid</var>: a pointer to store the OID (may be <code class="code">NULL</code> )
</p>
<p><var class="var">sizeof_oid</var>: initially holds the size of  <code class="code">oid</code> 
</p>
<p><var class="var">critical</var>: output variable with critical flag, may be <code class="code">NULL</code> .
</p>
<p>This function will extract the key purpose OIDs of the Certificate
specified by the given index.  These are stored in the Extended Key
Usage extension (2.5.29.37).  See the GNUTLS_KP_* definitions for
human readable names.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  if the provided buffer is
not long enough, and in that case the * <code class="code">sizeof_oid</code> will be
updated with the required size.  On success 0 is returned.
</p>
<p><strong class="strong">Since:</strong> 2.8.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fget_005fkey_005frsa_005fraw-1"><span>gnutls_x509_crq_get_key_rsa_raw<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fget_005fkey_005frsa_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fget_005fkey_005frsa_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fget_005fkey_005frsa_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_get_key_rsa_raw</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, gnutls_datum_t * <var class="var">m</var>, gnutls_datum_t * <var class="var">e</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fget_005fkey_005frsa_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: Holds the certificate
</p>
<p><var class="var">m</var>: will hold the modulus
</p>
<p><var class="var">e</var>: will hold the public exponent
</p>
<p>This function will export the RSA public key&rsquo;s parameters found in
the given structure.  The new parameters will be allocated using
<code class="code">gnutls_malloc()</code>  and will be stored in the appropriate datum.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.8.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fget_005fkey_005fusage-1"><span>gnutls_x509_crq_get_key_usage<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fget_005fkey_005fusage-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fget_005fkey_005fusage"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fget_005fkey_005fusage"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_get_key_usage</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, unsigned int * <var class="var">key_usage</var>, unsigned int * <var class="var">critical</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fget_005fkey_005fusage"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: should contain a <code class="code">gnutls_x509_crq_t</code>  type
</p>
<p><var class="var">key_usage</var>: where the key usage bits will be stored
</p>
<p><var class="var">critical</var>: will be non-zero if the extension is marked as critical
</p>
<p>This function will return certificate&rsquo;s key usage, by reading the
keyUsage X.509 extension (2.5.29.15).  The key usage value will
ORed values of the: <code class="code">GNUTLS_KEY_DIGITAL_SIGNATURE</code> ,
<code class="code">GNUTLS_KEY_NON_REPUDIATION</code> , <code class="code">GNUTLS_KEY_KEY_ENCIPHERMENT</code> ,
<code class="code">GNUTLS_KEY_DATA_ENCIPHERMENT</code> , <code class="code">GNUTLS_KEY_KEY_AGREEMENT</code> ,
<code class="code">GNUTLS_KEY_KEY_CERT_SIGN</code> , <code class="code">GNUTLS_KEY_CRL_SIGN</code> ,
<code class="code">GNUTLS_KEY_ENCIPHER_ONLY</code> , <code class="code">GNUTLS_KEY_DECIPHER_ONLY</code> .
</p>
<p><strong class="strong">Returns:</strong> the certificate key usage, or a negative error code in case of
parsing error.  If the certificate does not contain the keyUsage
extension <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  will be
returned.
</p>
<p><strong class="strong">Since:</strong> 2.8.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fget_005fpk_005falgorithm-1"><span>gnutls_x509_crq_get_pk_algorithm<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fget_005fpk_005falgorithm-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fget_005fpk_005falgorithm"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fget_005fpk_005falgorithm"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_get_pk_algorithm</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, unsigned int * <var class="var">bits</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fget_005fpk_005falgorithm"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: should contain a <code class="code">gnutls_x509_crq_t</code>  type
</p>
<p><var class="var">bits</var>: if bits is non-<code class="code">NULL</code>  it will hold the size of the parameters&rsquo; in bits
</p>
<p>This function will return the public key algorithm of a PKCS<code class="code">10</code> 
certificate request.
</p>
<p>If bits is non-<code class="code">NULL</code> , it should have enough size to hold the
parameters size in bits.  For RSA the bits returned is the modulus.
For DSA the bits returned are of the public exponent.
</p>
<p><strong class="strong">Returns:</strong> a member of the <code class="code">gnutls_pk_algorithm_t</code>  enumeration on
success, or a negative error code on error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fget_005fpk_005foid-1"><span>gnutls_x509_crq_get_pk_oid<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fget_005fpk_005foid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fget_005fpk_005foid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fget_005fpk_005foid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_get_pk_oid</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, char * <var class="var">oid</var>, size_t * <var class="var">oid_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fget_005fpk_005foid"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: should contain a <code class="code">gnutls_x509_crq_t</code>  type
</p>
<p><var class="var">oid</var>: a pointer to a buffer to hold the OID (may be null)
</p>
<p><var class="var">oid_size</var>: initially holds the size of  <code class="code">oid</code> 
</p>
<p>This function will return the OID of the public key algorithm
on that certificate request. This function
is useful in the case <code class="code">gnutls_x509_crq_get_pk_algorithm()</code> 
returned <code class="code">GNUTLS_PK_UNKNOWN</code> .
</p>
<p><strong class="strong">Returns:</strong> zero or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 3.5.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fget_005fprivate_005fkey_005fusage_005fperiod-1"><span>gnutls_x509_crq_get_private_key_usage_period<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fget_005fprivate_005fkey_005fusage_005fperiod-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fget_005fprivate_005fkey_005fusage_005fperiod"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fget_005fprivate_005fkey_005fusage_005fperiod"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_get_private_key_usage_period</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, time_t * <var class="var">activation</var>, time_t * <var class="var">expiration</var>, unsigned int * <var class="var">critical</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fget_005fprivate_005fkey_005fusage_005fperiod"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: should contain a <code class="code">gnutls_x509_crq_t</code>  type
</p>
<p><var class="var">activation</var>: The activation time
</p>
<p><var class="var">expiration</var>: The expiration time
</p>
<p><var class="var">critical</var>: the extension status
</p>
<p>This function will return the expiration and activation
times of the private key of the certificate.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> 
if the extension is not present, otherwise a negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fget_005fsignature_005falgorithm-1"><span>gnutls_x509_crq_get_signature_algorithm<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fget_005fsignature_005falgorithm-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fget_005fsignature_005falgorithm"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fget_005fsignature_005falgorithm"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_get_signature_algorithm</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fget_005fsignature_005falgorithm"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: should contain a <code class="code">gnutls_x509_cr_t</code>  type
</p>
<p>This function will return a value of the <code class="code">gnutls_sign_algorithm_t</code> 
enumeration that is the signature algorithm that has been used to
sign this certificate request.
</p>
<p>Since 3.6.0 this function never returns a negative error code.
Error cases and unknown/unsupported signature algorithms are
mapped to <code class="code">GNUTLS_SIGN_UNKNOWN</code> .
</p>
<p><strong class="strong">Returns:</strong> a <code class="code">gnutls_sign_algorithm_t</code>  value
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fget_005fsignature_005foid-1"><span>gnutls_x509_crq_get_signature_oid<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fget_005fsignature_005foid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fget_005fsignature_005foid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fget_005fsignature_005foid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_get_signature_oid</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, char * <var class="var">oid</var>, size_t * <var class="var">oid_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fget_005fsignature_005foid"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: should contain a <code class="code">gnutls_x509_crq_t</code>  type
</p>
<p><var class="var">oid</var>: a pointer to a buffer to hold the OID (may be null)
</p>
<p><var class="var">oid_size</var>: initially holds the size of  <code class="code">oid</code> 
</p>
<p>This function will return the OID of the signature algorithm
that has been used to sign this certificate request. This function
is useful in the case <code class="code">gnutls_x509_crq_get_signature_algorithm()</code> 
returned <code class="code">GNUTLS_SIGN_UNKNOWN</code> .
</p>
<p><strong class="strong">Returns:</strong> zero or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 3.5.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fget_005fspki-1"><span>gnutls_x509_crq_get_spki<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fget_005fspki-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fget_005fspki"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fget_005fspki"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_get_spki</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, gnutls_x509_spki_t <var class="var">spki</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fget_005fspki"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: should contain a <code class="code">gnutls_x509_crq_t</code>  type
</p>
<p><var class="var">spki</var>: a SubjectPublicKeyInfo structure of type <code class="code">gnutls_x509_spki_t</code> 
</p>
<p><var class="var">flags</var>: must be zero
</p>
<p>This function will return the public key information of a PKCS<code class="code">10</code> 
certificate request. The provided  <code class="code">spki</code> must be initialized.
</p>
<p><strong class="strong">Returns:</strong> Zero on success, or a negative error code on error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fget_005fsubject_005falt_005fname-1"><span>gnutls_x509_crq_get_subject_alt_name<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fget_005fsubject_005falt_005fname-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fget_005fsubject_005falt_005fname"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fget_005fsubject_005falt_005fname"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_get_subject_alt_name</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, unsigned int <var class="var">seq</var>, void * <var class="var">ret</var>, size_t * <var class="var">ret_size</var>, unsigned int * <var class="var">ret_type</var>, unsigned int * <var class="var">critical</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fget_005fsubject_005falt_005fname"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: should contain a <code class="code">gnutls_x509_crq_t</code>  type
</p>
<p><var class="var">seq</var>: specifies the sequence number of the alt name, 0 for the
first one, 1 for the second etc.
</p>
<p><var class="var">ret</var>: is the place where the alternative name will be copied to
</p>
<p><var class="var">ret_size</var>: holds the size of ret.
</p>
<p><var class="var">ret_type</var>: holds the <code class="code">gnutls_x509_subject_alt_name_t</code>  name type
</p>
<p><var class="var">critical</var>: will be non-zero if the extension is marked as critical
(may be null)
</p>
<p>This function will return the alternative names, contained in the
given certificate.  It is the same as
<code class="code">gnutls_x509_crq_get_subject_alt_name()</code>  except for the fact that it
will return the type of the alternative name in  <code class="code">ret_type</code> even if
the function fails for some reason (i.e.  the buffer provided is
not enough).
</p>
<p><strong class="strong">Returns:</strong> the alternative subject name type on success, one of the
enumerated <code class="code">gnutls_x509_subject_alt_name_t</code> .  It will return
<code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  if  <code class="code">ret_size</code> is not large enough to
hold the value.  In that case  <code class="code">ret_size</code> will be updated with the
required size.  If the certificate request does not have an
Alternative name with the specified sequence number then
<code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  is returned.
</p>
<p><strong class="strong">Since:</strong> 2.8.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fget_005fsubject_005falt_005fothername_005foid-1"><span>gnutls_x509_crq_get_subject_alt_othername_oid<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fget_005fsubject_005falt_005fothername_005foid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fget_005fsubject_005falt_005fothername_005foid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fget_005fsubject_005falt_005fothername_005foid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_get_subject_alt_othername_oid</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, unsigned int <var class="var">seq</var>, void * <var class="var">ret</var>, size_t * <var class="var">ret_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fget_005fsubject_005falt_005fothername_005foid"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: should contain a <code class="code">gnutls_x509_crq_t</code>  type
</p>
<p><var class="var">seq</var>: specifies the sequence number of the alt name (0 for the first one, 1 for the second etc.)
</p>
<p><var class="var">ret</var>: is the place where the otherName OID will be copied to
</p>
<p><var class="var">ret_size</var>: holds the size of ret.
</p>
<p>This function will extract the type OID of an otherName Subject
Alternative Name, contained in the given certificate, and return
the type as an enumerated element.
</p>
<p>This function is only useful if
<code class="code">gnutls_x509_crq_get_subject_alt_name()</code>  returned
<code class="code">GNUTLS_SAN_OTHERNAME</code> .
</p>
<p><strong class="strong">Returns:</strong> the alternative subject name type on success, one of the
enumerated gnutls_x509_subject_alt_name_t.  For supported OIDs,
it will return one of the virtual (GNUTLS_SAN_OTHERNAME_*) types,
e.g. <code class="code">GNUTLS_SAN_OTHERNAME_XMPP</code> , and <code class="code">GNUTLS_SAN_OTHERNAME</code>  for
unknown OIDs.  It will return <code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  if
 <code class="code">ret_size</code> is not large enough to hold the value.  In that case
 <code class="code">ret_size</code> will be updated with the required size.  If the
certificate does not have an Alternative name with the specified
sequence number and with the otherName type then
<code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  is returned.
</p>
<p><strong class="strong">Since:</strong> 2.8.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fget_005ftlsfeatures-1"><span>gnutls_x509_crq_get_tlsfeatures<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fget_005ftlsfeatures-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fget_005ftlsfeatures"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fget_005ftlsfeatures"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_get_tlsfeatures</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, gnutls_x509_tlsfeatures_t <var class="var">features</var>, unsigned int <var class="var">flags</var>, unsigned int * <var class="var">critical</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fget_005ftlsfeatures"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: An X.509 certificate request
</p>
<p><var class="var">features</var>: If the function succeeds, the
features will be stored in this variable.
</p>
<p><var class="var">flags</var>: zero or <code class="code">GNUTLS_EXT_FLAG_APPEND</code> 
</p>
<p><var class="var">critical</var>: the extension status
</p>
<p>This function will get the X.509 TLS features
extension structure from the certificate request.
The returned structure needs to be freed using
<code class="code">gnutls_x509_tlsfeatures_deinit()</code> .
</p>
<p>When the  <code class="code">flags</code> is set to <code class="code">GNUTLS_EXT_FLAG_APPEND</code> ,
then if the  <code class="code">features</code> structure is empty this function will behave
identically as if the flag was not set. Otherwise if there are elements 
in the  <code class="code">features</code> structure then they will be merged with.
</p>
<p>Note that  <code class="code">features</code> must be initialized prior to calling this function.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.5.1
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fget_005fversion-1"><span>gnutls_x509_crq_get_version<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fget_005fversion-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fget_005fversion"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fget_005fversion"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_get_version</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fget_005fversion"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: should contain a <code class="code">gnutls_x509_crq_t</code>  type
</p>
<p>This function will return the version of the specified Certificate
request.
</p>
<p><strong class="strong">Returns:</strong> version of certificate request, or a negative error code on
error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fimport-1"><span>gnutls_x509_crq_import<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fimport-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fimport"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fimport"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_import</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, const gnutls_datum_t * <var class="var">data</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fimport"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: The data to store the parsed certificate request.
</p>
<p><var class="var">data</var>: The DER or PEM encoded certificate.
</p>
<p><var class="var">format</var>: One of DER or PEM
</p>
<p>This function will convert the given DER or PEM encoded certificate
request to a <code class="code">gnutls_x509_crq_t</code>  type.  The output will be
stored in  <code class="code">crq</code> .
</p>
<p>If the Certificate is PEM encoded it should have a header of &quot;NEW
CERTIFICATE REQUEST&quot;.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005finit-1"><span>gnutls_x509_crq_init<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005finit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005finit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005finit"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_init</strong> <code class="def-code-arguments">(gnutls_x509_crq_t * <var class="var">crq</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005finit"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: A pointer to the type to be initialized
</p>
<p>This function will initialize a PKCS<code class="code">10</code>  certificate request
structure.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fprint-1"><span>gnutls_x509_crq_print<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fprint-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fprint"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fprint"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_print</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, gnutls_certificate_print_formats_t <var class="var">format</var>, gnutls_datum_t * <var class="var">out</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fprint"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: The data to be printed
</p>
<p><var class="var">format</var>: Indicate the format to use
</p>
<p><var class="var">out</var>: Newly allocated datum with null terminated string.
</p>
<p>This function will pretty print a certificate request, suitable for
display to a human.
</p>
<p>The output  <code class="code">out</code> needs to be deallocated using <code class="code">gnutls_free()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.8.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fset_005fattribute_005fby_005foid-1"><span>gnutls_x509_crq_set_attribute_by_oid<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fset_005fattribute_005fby_005foid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fset_005fattribute_005fby_005foid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fset_005fattribute_005fby_005foid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_set_attribute_by_oid</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, const char * <var class="var">oid</var>, void * <var class="var">buf</var>, size_t <var class="var">buf_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fset_005fattribute_005fby_005foid"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: should contain a <code class="code">gnutls_x509_crq_t</code>  type
</p>
<p><var class="var">oid</var>: holds an Object Identifier in a null-terminated string
</p>
<p><var class="var">buf</var>: a pointer to a structure that holds the attribute data
</p>
<p><var class="var">buf_size</var>: holds the size of  <code class="code">buf</code> 
</p>
<p>This function will set the attribute in the certificate request
specified by the given Object ID. The provided attribute must be be DER
encoded.
</p>
<p>Attributes in a certificate request is an optional set of data
appended to the request. Their interpretation depends on the CA policy.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fset_005fbasic_005fconstraints-1"><span>gnutls_x509_crq_set_basic_constraints<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fset_005fbasic_005fconstraints-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fset_005fbasic_005fconstraints"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fset_005fbasic_005fconstraints"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_set_basic_constraints</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, unsigned int <var class="var">ca</var>, int <var class="var">pathLenConstraint</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fset_005fbasic_005fconstraints"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: a certificate request of type <code class="code">gnutls_x509_crq_t</code> 
</p>
<p><var class="var">ca</var>: true(1) or false(0) depending on the Certificate authority status.
</p>
<p><var class="var">pathLenConstraint</var>: non-negative error codes indicate maximum length of path,
and negative error codes indicate that the pathLenConstraints field should
not be present.
</p>
<p>This function will set the basicConstraints certificate extension.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.8.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fset_005fchallenge_005fpassword-1"><span>gnutls_x509_crq_set_challenge_password<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fset_005fchallenge_005fpassword-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fset_005fchallenge_005fpassword"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fset_005fchallenge_005fpassword"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_set_challenge_password</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, const char * <var class="var">pass</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fset_005fchallenge_005fpassword"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: should contain a <code class="code">gnutls_x509_crq_t</code>  type
</p>
<p><var class="var">pass</var>: holds a (0)-terminated password
</p>
<p>This function will set a challenge password to be used when
revoking the request.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fset_005fdn-1"><span>gnutls_x509_crq_set_dn<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fset_005fdn-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fset_005fdn"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fset_005fdn"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_set_dn</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, const char * <var class="var">dn</var>, const char ** <var class="var">err</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fset_005fdn"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: a certificate of type <code class="code">gnutls_x509_crq_t</code> 
</p>
<p><var class="var">dn</var>: a comma separated DN string (RFC4514)
</p>
<p><var class="var">err</var>: indicates the error position (if any)
</p>
<p>This function will set the DN on the provided certificate.
The input string should be plain ASCII or UTF-8 encoded. On
DN parsing error <code class="code">GNUTLS_E_PARSING_ERROR</code>  is returned.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fset_005fdn_005fby_005foid-1"><span>gnutls_x509_crq_set_dn_by_oid<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fset_005fdn_005fby_005foid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fset_005fdn_005fby_005foid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fset_005fdn_005fby_005foid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_set_dn_by_oid</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, const char * <var class="var">oid</var>, unsigned int <var class="var">raw_flag</var>, const void * <var class="var">data</var>, unsigned int <var class="var">sizeof_data</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fset_005fdn_005fby_005foid"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: should contain a <code class="code">gnutls_x509_crq_t</code>  type
</p>
<p><var class="var">oid</var>: holds an Object Identifier in a (0)-terminated string
</p>
<p><var class="var">raw_flag</var>: must be 0, or 1 if the data are DER encoded
</p>
<p><var class="var">data</var>: a pointer to the input data
</p>
<p><var class="var">sizeof_data</var>: holds the size of  <code class="code">data</code> 
</p>
<p>This function will set the part of the name of the Certificate
request subject, specified by the given OID.  The input string
should be ASCII or UTF-8 encoded.
</p>
<p>Some helper macros with popular OIDs can be found in gnutls/x509.h
With this function you can only set the known OIDs.  You can test
for known OIDs using <code class="code">gnutls_x509_dn_oid_known()</code> .  For OIDs that are
not known (by gnutls) you should properly DER encode your data, and
call this function with raw_flag set.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fset_005fextension_005fby_005foid-1"><span>gnutls_x509_crq_set_extension_by_oid<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fset_005fextension_005fby_005foid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fset_005fextension_005fby_005foid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fset_005fextension_005fby_005foid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_set_extension_by_oid</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, const char * <var class="var">oid</var>, const void * <var class="var">buf</var>, size_t <var class="var">sizeof_buf</var>, unsigned int <var class="var">critical</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fset_005fextension_005fby_005foid"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: a certificate of type <code class="code">gnutls_x509_crq_t</code> 
</p>
<p><var class="var">oid</var>: holds an Object Identifier in null terminated string
</p>
<p><var class="var">buf</var>: a pointer to a DER encoded data
</p>
<p><var class="var">sizeof_buf</var>: holds the size of  <code class="code">buf</code> 
</p>
<p><var class="var">critical</var>: should be non-zero if the extension is to be marked as critical
</p>
<p>This function will set an the extension, by the specified OID, in
the certificate request.  The extension data should be binary data DER
encoded.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fset_005fkey-1"><span>gnutls_x509_crq_set_key<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fset_005fkey-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fset_005fkey"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fset_005fkey-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_set_key</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, gnutls_x509_privkey_t <var class="var">key</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fset_005fkey-1"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: should contain a <code class="code">gnutls_x509_crq_t</code>  type
</p>
<p><var class="var">key</var>: holds a private key
</p>
<p>This function will set the public parameters from the given private
key to the request.  
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fset_005fkey_005fpurpose_005foid-1"><span>gnutls_x509_crq_set_key_purpose_oid<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fset_005fkey_005fpurpose_005foid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fset_005fkey_005fpurpose_005foid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fset_005fkey_005fpurpose_005foid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_set_key_purpose_oid</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, const void * <var class="var">oid</var>, unsigned int <var class="var">critical</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fset_005fkey_005fpurpose_005foid"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: a certificate of type <code class="code">gnutls_x509_crq_t</code> 
</p>
<p><var class="var">oid</var>: a pointer to a null-terminated string that holds the OID
</p>
<p><var class="var">critical</var>: Whether this extension will be critical or not
</p>
<p>This function will set the key purpose OIDs of the Certificate.
These are stored in the Extended Key Usage extension (2.5.29.37)
See the GNUTLS_KP_* definitions for human readable names.
</p>
<p>Subsequent calls to this function will append OIDs to the OID list.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.8.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fset_005fkey_005frsa_005fraw-1"><span>gnutls_x509_crq_set_key_rsa_raw<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fset_005fkey_005frsa_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fset_005fkey_005frsa_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fset_005fkey_005frsa_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_set_key_rsa_raw</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, const gnutls_datum_t * <var class="var">m</var>, const gnutls_datum_t * <var class="var">e</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fset_005fkey_005frsa_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: should contain a <code class="code">gnutls_x509_crq_t</code>  type
</p>
<p><var class="var">m</var>: holds the modulus
</p>
<p><var class="var">e</var>: holds the public exponent
</p>
<p>This function will set the public parameters from the given private
key to the request. Only RSA keys are currently supported.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fset_005fkey_005fusage-1"><span>gnutls_x509_crq_set_key_usage<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fset_005fkey_005fusage-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fset_005fkey_005fusage"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fset_005fkey_005fusage"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_set_key_usage</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, unsigned int <var class="var">usage</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fset_005fkey_005fusage"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: a certificate request of type <code class="code">gnutls_x509_crq_t</code> 
</p>
<p><var class="var">usage</var>: an ORed sequence of the GNUTLS_KEY_* elements.
</p>
<p>This function will set the keyUsage certificate extension.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.8.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fset_005fprivate_005fkey_005fusage_005fperiod-1"><span>gnutls_x509_crq_set_private_key_usage_period<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fset_005fprivate_005fkey_005fusage_005fperiod-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fset_005fprivate_005fkey_005fusage_005fperiod"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fset_005fprivate_005fkey_005fusage_005fperiod"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_set_private_key_usage_period</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, time_t <var class="var">activation</var>, time_t <var class="var">expiration</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fset_005fprivate_005fkey_005fusage_005fperiod"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: a certificate of type <code class="code">gnutls_x509_crq_t</code> 
</p>
<p><var class="var">activation</var>: The activation time
</p>
<p><var class="var">expiration</var>: The expiration time
</p>
<p>This function will set the private key usage period extension (2.5.29.16).
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fset_005fspki-1"><span>gnutls_x509_crq_set_spki<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fset_005fspki-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fset_005fspki"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fset_005fspki"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_set_spki</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, const gnutls_x509_spki_t <var class="var">spki</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fset_005fspki"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: a certificate request of type <code class="code">gnutls_x509_crq_t</code> 
</p>
<p><var class="var">spki</var>: a SubjectPublicKeyInfo structure of type <code class="code">gnutls_x509_spki_t</code> 
</p>
<p><var class="var">flags</var>: must be zero
</p>
<p>This function will set the certificate request&rsquo;s subject public key
information explicitly. This is intended to be used in the cases
where a single public key (e.g., RSA) can be used for multiple
signature algorithms (RSA PKCS1-1.5, and RSA-PSS).
</p>
<p>To export the public key (i.e., the SubjectPublicKeyInfo part), check
<code class="code">gnutls_pubkey_import_x509()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fset_005fsubject_005falt_005fname-1"><span>gnutls_x509_crq_set_subject_alt_name<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fset_005fsubject_005falt_005fname-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fset_005fsubject_005falt_005fname"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fset_005fsubject_005falt_005fname"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_set_subject_alt_name</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, gnutls_x509_subject_alt_name_t <var class="var">nt</var>, const void * <var class="var">data</var>, unsigned int <var class="var">data_size</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fset_005fsubject_005falt_005fname"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: a certificate request of type <code class="code">gnutls_x509_crq_t</code> 
</p>
<p><var class="var">nt</var>: is one of the <code class="code">gnutls_x509_subject_alt_name_t</code>  enumerations
</p>
<p><var class="var">data</var>: The data to be set
</p>
<p><var class="var">data_size</var>: The size of data to be set
</p>
<p><var class="var">flags</var>: <code class="code">GNUTLS_FSAN_SET</code>  to clear previous data or
<code class="code">GNUTLS_FSAN_APPEND</code>  to append.
</p>
<p>This function will set the subject alternative name certificate
extension.  It can set the following types:
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.8.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fset_005fsubject_005falt_005fothername-1"><span>gnutls_x509_crq_set_subject_alt_othername<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fset_005fsubject_005falt_005fothername-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fset_005fsubject_005falt_005fothername"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fset_005fsubject_005falt_005fothername"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_set_subject_alt_othername</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, const char * <var class="var">oid</var>, const void * <var class="var">data</var>, unsigned int <var class="var">data_size</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fset_005fsubject_005falt_005fothername"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: a certificate request of type <code class="code">gnutls_x509_crq_t</code> 
</p>
<p><var class="var">oid</var>: is the othername OID
</p>
<p><var class="var">data</var>: The data to be set
</p>
<p><var class="var">data_size</var>: The size of data to be set
</p>
<p><var class="var">flags</var>: <code class="code">GNUTLS_FSAN_SET</code>  to clear previous data or
<code class="code">GNUTLS_FSAN_APPEND</code>  to append.
</p>
<p>This function will set the subject alternative name certificate
extension.  It can set the following types:
</p>
<p>The values set must be binary values and must be properly DER encoded.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.5.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fset_005ftlsfeatures-1"><span>gnutls_x509_crq_set_tlsfeatures<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fset_005ftlsfeatures-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fset_005ftlsfeatures"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fset_005ftlsfeatures"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_set_tlsfeatures</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, gnutls_x509_tlsfeatures_t <var class="var">features</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fset_005ftlsfeatures"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: An X.509 certificate request
</p>
<p><var class="var">features</var>: If the function succeeds, the
features will be added to the certificate
request.
</p>
<p>This function will set the certificate request&rsquo;s
X.509 TLS extension from the given structure.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.5.1
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fset_005fversion-1"><span>gnutls_x509_crq_set_version<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fset_005fversion-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fset_005fversion"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fset_005fversion"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_set_version</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, unsigned int <var class="var">version</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fset_005fversion"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: should contain a <code class="code">gnutls_x509_crq_t</code>  type
</p>
<p><var class="var">version</var>: holds the version number, for v1 Requests must be 1
</p>
<p>This function will set the version of the certificate request.  For
version 1 requests this must be one.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fsign-1"><span>gnutls_x509_crq_sign<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fsign-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fsign"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fsign"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_sign</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, gnutls_x509_privkey_t <var class="var">key</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fsign"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: should contain a <code class="code">gnutls_x509_crq_t</code>  type
</p>
<p><var class="var">key</var>: holds a private key
</p>
<p>This function is the same a <code class="code">gnutls_x509_crq_sign2()</code>  with no flags,
and an appropriate hash algorithm. The hash algorithm used may
vary between versions of GnuTLS, and it is tied to the security
level of the issuer&rsquo;s public key.
</p>
<p>A known limitation of this function is, that a newly-signed request will not
be fully functional (e.g., for signature verification), until it
is exported an re-imported.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fsign2-1"><span>gnutls_x509_crq_sign2<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fsign2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fsign2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fsign2-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_sign2</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, gnutls_x509_privkey_t <var class="var">key</var>, gnutls_digest_algorithm_t <var class="var">dig</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fsign2-1"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: should contain a <code class="code">gnutls_x509_crq_t</code>  type
</p>
<p><var class="var">key</var>: holds a private key
</p>
<p><var class="var">dig</var>: The message digest to use, i.e., <code class="code">GNUTLS_DIG_SHA256</code> 
</p>
<p><var class="var">flags</var>: must be 0
</p>
<p>This function will sign the certificate request with a private key.
This must be the same key as the one used in
<code class="code">gnutls_x509_crt_set_key()</code>  since a certificate request is self
signed.
</p>
<p>This must be the last step in a certificate request generation
since all the previously set parameters are now signed.
</p>
<p>A known limitation of this function is, that a newly-signed request will not
be fully functional (e.g., for signature verification), until it
is exported an re-imported.
</p>
<p>After GnuTLS 3.6.1 the value of  <code class="code">dig</code> may be <code class="code">GNUTLS_DIG_UNKNOWN</code> ,
and in that case, a suitable but reasonable for the key algorithm will be selected.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
<code class="code">GNUTLS_E_ASN1_VALUE_NOT_FOUND</code>  is returned if you didn&rsquo;t set all
information in the certificate request (e.g., the version using
<code class="code">gnutls_x509_crq_set_version()</code> ).
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fverify-1"><span>gnutls_x509_crq_verify<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fverify-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fverify"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fverify"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_verify</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fverify"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: is the crq to be verified
</p>
<p><var class="var">flags</var>: Flags that may be used to change the verification algorithm. Use OR of the gnutls_certificate_verify_flags enumerations.
</p>
<p>This function will verify self signature in the certificate
request and return its status.
</p>
<p><strong class="strong">Returns:</strong> In case of a verification failure <code class="code">GNUTLS_E_PK_SIG_VERIFY_FAILED</code>  
is returned, and zero or positive code on success.
</p>
<p>Since 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fcheck_005femail-1"><span>gnutls_x509_crt_check_email<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fcheck_005femail-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fcheck_005femail"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fcheck_005femail"><span class="category-def">Function: </span><span><code class="def-type">unsigned</code> <strong class="def-name">gnutls_x509_crt_check_email</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, const char * <var class="var">email</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fcheck_005femail"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain an gnutls_x509_crt_t type
</p>
<p><var class="var">email</var>: A null terminated string that contains an email address (RFC822)
</p>
<p><var class="var">flags</var>: should be zero
</p>
<p>This function will check if the given certificate&rsquo;s subject matches
the given email address.
</p>
<p><strong class="strong">Returns:</strong> non-zero for a successful match, and zero on failure.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fcheck_005fhostname-1"><span>gnutls_x509_crt_check_hostname<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fcheck_005fhostname-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fcheck_005fhostname"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fcheck_005fhostname"><span class="category-def">Function: </span><span><code class="def-type">unsigned</code> <strong class="def-name">gnutls_x509_crt_check_hostname</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, const char * <var class="var">hostname</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fcheck_005fhostname"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain an gnutls_x509_crt_t type
</p>
<p><var class="var">hostname</var>: A null terminated string that contains a DNS name
</p>
<p>This function will check if the given certificate&rsquo;s subject matches
the given hostname.  This is a basic implementation of the matching
described in RFC6125, and takes into account wildcards,
and the DNSName/IPAddress subject alternative name PKIX extension.
</p>
<p>For details see also <code class="code">gnutls_x509_crt_check_hostname2()</code> .
</p>
<p><strong class="strong">Returns:</strong> non-zero for a successful match, and zero on failure.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fcheck_005fhostname2-1"><span>gnutls_x509_crt_check_hostname2<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fcheck_005fhostname2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fcheck_005fhostname2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fcheck_005fhostname2"><span class="category-def">Function: </span><span><code class="def-type">unsigned</code> <strong class="def-name">gnutls_x509_crt_check_hostname2</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, const char * <var class="var">hostname</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fcheck_005fhostname2"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain an gnutls_x509_crt_t type
</p>
<p><var class="var">hostname</var>: A null terminated string that contains a DNS name
</p>
<p><var class="var">flags</var>: gnutls_certificate_verify_flags
</p>
<p>This function will check if the given certificate&rsquo;s subject matches
the given hostname.  This is a basic implementation of the matching
described in RFC6125, and takes into account wildcards,
and the DNSName/IPAddress subject alternative name PKIX extension.
</p>
<p>IPv4 addresses are accepted by this function in the dotted-decimal
format (e.g, ddd.ddd.ddd.ddd), and IPv6 addresses in the hexadecimal
x:x:x:x:x:x:x:x format. For them the IPAddress subject alternative
name extension is consulted. Previous versions to 3.6.0 of GnuTLS
in case of a non-match would consult (in a non-standard extension)
the DNSname and CN fields. This is no longer the case.
</p>
<p>When the flag <code class="code">GNUTLS_VERIFY_DO_NOT_ALLOW_WILDCARDS</code>  is specified no
wildcards are considered. Otherwise they are only considered if the
domain name consists of three components or more, and the wildcard
starts at the leftmost position.
When the flag <code class="code">GNUTLS_VERIFY_DO_NOT_ALLOW_IP_MATCHES</code>  is specified,
the input will be treated as a DNS name, and matching of textual IP addresses
against the IPAddress part of the alternative name will not be allowed.
</p>
<p>The function <code class="code">gnutls_x509_crt_check_ip()</code>  is available for matching
IP addresses.
</p>
<p><strong class="strong">Returns:</strong> non-zero for a successful match, and zero on failure.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fcheck_005fip-1"><span>gnutls_x509_crt_check_ip<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fcheck_005fip-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fcheck_005fip"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fcheck_005fip"><span class="category-def">Function: </span><span><code class="def-type">unsigned</code> <strong class="def-name">gnutls_x509_crt_check_ip</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, const unsigned char * <var class="var">ip</var>, unsigned int <var class="var">ip_size</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fcheck_005fip"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain an gnutls_x509_crt_t type
</p>
<p><var class="var">ip</var>: A pointer to the raw IP address
</p>
<p><var class="var">ip_size</var>: the number of bytes in ip (4 or 16)
</p>
<p><var class="var">flags</var>: should be zero
</p>
<p>This function will check if the IP allowed IP addresses in 
the certificate&rsquo;s subject alternative name match the provided
IP address.
</p>
<p><strong class="strong">Returns:</strong> non-zero for a successful match, and zero on failure.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fcheck_005fissuer-1"><span>gnutls_x509_crt_check_issuer<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fcheck_005fissuer-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fcheck_005fissuer"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fcheck_005fissuer"><span class="category-def">Function: </span><span><code class="def-type">unsigned</code> <strong class="def-name">gnutls_x509_crt_check_issuer</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, gnutls_x509_crt_t <var class="var">issuer</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fcheck_005fissuer"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: is the certificate to be checked
</p>
<p><var class="var">issuer</var>: is the certificate of a possible issuer
</p>
<p>This function will check if the given certificate was issued by the
given issuer. It checks the DN fields and the authority
key identifier and subject key identifier fields match.
</p>
<p>If the same certificate is provided at the  <code class="code">cert</code> and  <code class="code">issuer</code> fields,
it will check whether the certificate is self-signed.
</p>
<p><strong class="strong">Returns:</strong> It will return true (1) if the given certificate is issued
by the given issuer, and false (0) if not.  
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fcheck_005fkey_005fpurpose-1"><span>gnutls_x509_crt_check_key_purpose<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fcheck_005fkey_005fpurpose-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fcheck_005fkey_005fpurpose"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fcheck_005fkey_005fpurpose"><span class="category-def">Function: </span><span><code class="def-type">unsigned</code> <strong class="def-name">gnutls_x509_crt_check_key_purpose</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, const char * <var class="var">purpose</var>, unsigned <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fcheck_005fkey_005fpurpose"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">purpose</var>: a key purpose OID (e.g., <code class="code">GNUTLS_KP_CODE_SIGNING</code> )
</p>
<p><var class="var">flags</var>: zero or <code class="code">GNUTLS_KP_FLAG_DISALLOW_ANY</code> 
</p>
<p>This function will check whether the given certificate matches
the provided key purpose. If  <code class="code">flags</code> contains <code class="code">GNUTLS_KP_FLAG_ALLOW_ANY</code>  then
it a certificate marked for any purpose will not match.
</p>
<p><strong class="strong">Returns:</strong> zero if the key purpose doesn&rsquo;t match, and non-zero otherwise.
</p>
<p><strong class="strong">Since:</strong> 3.5.6
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fcheck_005frevocation-1"><span>gnutls_x509_crt_check_revocation<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fcheck_005frevocation-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fcheck_005frevocation"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fcheck_005frevocation"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_check_revocation</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, const gnutls_x509_crl_t * <var class="var">crl_list</var>, unsigned <var class="var">crl_list_length</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fcheck_005frevocation"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">crl_list</var>: should contain a list of gnutls_x509_crl_t types
</p>
<p><var class="var">crl_list_length</var>: the length of the crl_list
</p>
<p>This function will check if the given certificate is
revoked.  It is assumed that the CRLs have been verified before.
</p>
<p><strong class="strong">Returns:</strong> 0 if the certificate is NOT revoked, and 1 if it is.  A
negative error code is returned on error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fcpy_005fcrl_005fdist_005fpoints-1"><span>gnutls_x509_crt_cpy_crl_dist_points<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fcpy_005fcrl_005fdist_005fpoints-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fcpy_005fcrl_005fdist_005fpoints"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fcpy_005fcrl_005fdist_005fpoints"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_cpy_crl_dist_points</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">dst</var>, gnutls_x509_crt_t <var class="var">src</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fcpy_005fcrl_005fdist_005fpoints"> &para;</a></span></dt>
<dd><p><var class="var">dst</var>: a certificate of type <code class="code">gnutls_x509_crt_t</code> 
</p>
<p><var class="var">src</var>: the certificate where the dist points will be copied from
</p>
<p>This function will copy the CRL distribution points certificate
extension, from the source to the destination certificate.
This may be useful to copy from a CA certificate to issued ones.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fdeinit-1"><span>gnutls_x509_crt_deinit<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_x509_crt_deinit</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: The data to be deinitialized
</p>
<p>This function will deinitialize a certificate structure.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fequals-1"><span>gnutls_x509_crt_equals<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fequals-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fequals"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fequals"><span class="category-def">Function: </span><span><code class="def-type">unsigned</code> <strong class="def-name">gnutls_x509_crt_equals</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert1</var>, gnutls_x509_crt_t <var class="var">cert2</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fequals"> &para;</a></span></dt>
<dd><p><var class="var">cert1</var>: The first certificate
</p>
<p><var class="var">cert2</var>: The second certificate
</p>
<p>This function will compare two X.509 certificate structures.
</p>
<p><strong class="strong">Returns:</strong> On equality non-zero is returned, otherwise zero.
</p>
<p><strong class="strong">Since:</strong> 3.5.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fequals2-1"><span>gnutls_x509_crt_equals2<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fequals2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fequals2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fequals2"><span class="category-def">Function: </span><span><code class="def-type">unsigned</code> <strong class="def-name">gnutls_x509_crt_equals2</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert1</var>, const gnutls_datum_t * <var class="var">der</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fequals2"> &para;</a></span></dt>
<dd><p><var class="var">cert1</var>: The first certificate
</p>
<p><var class="var">der</var>: A DER encoded certificate
</p>
<p>This function will compare an X.509 certificate structures, with DER
encoded certificate data.
</p>
<p><strong class="strong">Returns:</strong> On equality non-zero is returned, otherwise zero.
</p>
<p><strong class="strong">Since:</strong> 3.5.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fexport-1"><span>gnutls_x509_crt_export<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fexport-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fexport"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fexport"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_export</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, void * <var class="var">output_data</var>, size_t * <var class="var">output_data_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fexport"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: Holds the certificate
</p>
<p><var class="var">format</var>: the format of output params. One of PEM or DER.
</p>
<p><var class="var">output_data</var>: will contain a certificate PEM or DER encoded
</p>
<p><var class="var">output_data_size</var>: holds the size of output_data (and will be
replaced by the actual size of parameters)
</p>
<p>This function will export the certificate to DER or PEM format.
</p>
<p>If the buffer provided is not long enough to hold the output, then
*output_data_size is updated and GNUTLS_E_SHORT_MEMORY_BUFFER will
be returned.
</p>
<p>If the structure is PEM encoded, it will have a header
of &quot;BEGIN CERTIFICATE&quot;.
</p>
<p><strong class="strong">Returns:</strong> In case of failure a negative error code will be
returned, and 0 on success.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fexport2-1"><span>gnutls_x509_crt_export2<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fexport2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fexport2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fexport2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_export2</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, gnutls_datum_t * <var class="var">out</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fexport2"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: Holds the certificate
</p>
<p><var class="var">format</var>: the format of output params. One of PEM or DER.
</p>
<p><var class="var">out</var>: will contain a certificate PEM or DER encoded
</p>
<p>This function will export the certificate to DER or PEM format.
The output buffer is allocated using <code class="code">gnutls_malloc()</code> .
</p>
<p>If the structure is PEM encoded, it will have a header
of &quot;BEGIN CERTIFICATE&quot;.
</p>
<p><strong class="strong">Returns:</strong> In case of failure a negative error code will be
returned, and 0 on success.
</p>
<p><strong class="strong">Since:</strong> 3.1.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005factivation_005ftime-1"><span>gnutls_x509_crt_get_activation_time<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005factivation_005ftime-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005factivation_005ftime"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005factivation_005ftime"><span class="category-def">Function: </span><span><code class="def-type">time_t</code> <strong class="def-name">gnutls_x509_crt_get_activation_time</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005factivation_005ftime"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p>This function will return the time this Certificate was or will be
activated.
</p>
<p><strong class="strong">Returns:</strong> activation time, or (time_t)-1 on error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fauthority_005finfo_005faccess-1"><span>gnutls_x509_crt_get_authority_info_access<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fauthority_005finfo_005faccess-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fauthority_005finfo_005faccess"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fauthority_005finfo_005faccess"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_authority_info_access</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, unsigned int <var class="var">seq</var>, int <var class="var">what</var>, gnutls_datum_t * <var class="var">data</var>, unsigned int * <var class="var">critical</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fauthority_005finfo_005faccess"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: Holds the certificate
</p>
<p><var class="var">seq</var>: specifies the sequence number of the access descriptor (0 for the first one, 1 for the second etc.)
</p>
<p><var class="var">what</var>: what data to get, a <code class="code">gnutls_info_access_what_t</code>  type.
</p>
<p><var class="var">data</var>: output data to be freed with <code class="code">gnutls_free()</code> .
</p>
<p><var class="var">critical</var>: pointer to output integer that is set to non-zero if the extension is marked as critical (may be <code class="code">NULL</code> )
</p>
<p>Note that a simpler API to access the authority info data is provided
by <code class="code">gnutls_x509_aia_get()</code>  and <code class="code">gnutls_x509_ext_import_aia()</code> .
</p>
<p>This function extracts the Authority Information Access (AIA)
extension, see RFC 5280 section 4.2.2.1 for more information.  The
AIA extension holds a sequence of AccessDescription (AD) data.
</p>
<p>The  <code class="code">seq</code> input parameter is used to indicate which member of the
sequence the caller is interested in.  The first member is 0, the
second member 1 and so on.  When the  <code class="code">seq</code> value is out of bounds,
<code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  is returned.
</p>
<p>The type of data returned in  <code class="code">data</code> is specified via  <code class="code">what</code> which
should be <code class="code">gnutls_info_access_what_t</code>  values.
</p>
<p>If  <code class="code">what</code> is <code class="code">GNUTLS_IA_ACCESSMETHOD_OID</code>  then  <code class="code">data</code> will hold the
accessMethod OID (e.g., &quot;1.3.6.1.5.5.7.48.1&quot;).
</p>
<p>If  <code class="code">what</code> is <code class="code">GNUTLS_IA_ACCESSLOCATION_GENERALNAME_TYPE</code> ,  <code class="code">data</code> will
hold the accessLocation GeneralName type (e.g.,
&quot;uniformResourceIdentifier&quot;).
</p>
<p>If  <code class="code">what</code> is <code class="code">GNUTLS_IA_URI</code> ,  <code class="code">data</code> will hold the accessLocation URI
data.  Requesting this  <code class="code">what</code> value leads to an error if the
accessLocation is not of the &quot;uniformResourceIdentifier&quot; type.
</p>
<p>If  <code class="code">what</code> is <code class="code">GNUTLS_IA_OCSP_URI</code> ,  <code class="code">data</code> will hold the OCSP URI.
Requesting this  <code class="code">what</code> value leads to an error if the accessMethod
is not 1.3.6.1.5.5.7.48.1 aka OCSP, or if accessLocation is not of
the &quot;uniformResourceIdentifier&quot; type. In that case <code class="code">GNUTLS_E_UNKNOWN_ALGORITHM</code> 
will be returned, and  <code class="code">seq</code> should be increased and this function
called again.
</p>
<p>If  <code class="code">what</code> is <code class="code">GNUTLS_IA_CAISSUERS_URI</code> ,  <code class="code">data</code> will hold the caIssuers
URI.  Requesting this  <code class="code">what</code> value leads to an error if the
accessMethod is not 1.3.6.1.5.5.7.48.2 aka caIssuers, or if
accessLocation is not of the &quot;uniformResourceIdentifier&quot; type.
In that case handle as in <code class="code">GNUTLS_IA_OCSP_URI</code> .
</p>
<p>More  <code class="code">what</code> values may be allocated in the future as needed.
</p>
<p>If  <code class="code">data</code> is NULL, the function does the same without storing the
output data, that is, it will set  <code class="code">critical</code> and do error checking
as usual.
</p>
<p>The value of the critical flag is returned in * <code class="code">critical</code> .  Supply a
NULL  <code class="code">critical</code> if you want the function to make sure the extension
is non-critical, as required by RFC 5280.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, <code class="code">GNUTLS_E_INVALID_REQUEST</code>  on
invalid  <code class="code">crt</code> , <code class="code">GNUTLS_E_CONSTRAINT_ERROR</code>  if the extension is
incorrectly marked as critical (use a non-NULL  <code class="code">critical</code> to
override), <code class="code">GNUTLS_E_UNKNOWN_ALGORITHM</code>  if the requested OID does
not match (e.g., when using <code class="code">GNUTLS_IA_OCSP_URI</code> ), otherwise a
negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fauthority_005fkey_005fgn_005fserial-1"><span>gnutls_x509_crt_get_authority_key_gn_serial<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fauthority_005fkey_005fgn_005fserial-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fauthority_005fkey_005fgn_005fserial"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fauthority_005fkey_005fgn_005fserial"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_authority_key_gn_serial</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, unsigned int <var class="var">seq</var>, void * <var class="var">alt</var>, size_t * <var class="var">alt_size</var>, unsigned int * <var class="var">alt_type</var>, void * <var class="var">serial</var>, size_t * <var class="var">serial_size</var>, unsigned int * <var class="var">critical</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fauthority_005fkey_005fgn_005fserial"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">seq</var>: specifies the sequence number of the alt name (0 for the first one, 1 for the second etc.)
</p>
<p><var class="var">alt</var>: is the place where the alternative name will be copied to
</p>
<p><var class="var">alt_size</var>: holds the size of alt.
</p>
<p><var class="var">alt_type</var>: holds the type of the alternative name (one of gnutls_x509_subject_alt_name_t).
</p>
<p><var class="var">serial</var>: buffer to store the serial number (may be null)
</p>
<p><var class="var">serial_size</var>: Holds the size of the serial field (may be null)
</p>
<p><var class="var">critical</var>: will be non-zero if the extension is marked as critical (may be null)
</p>
<p>This function will return the X.509 authority key
identifier when stored as a general name (authorityCertIssuer)
and serial number.
</p>
<p>Because more than one general names might be stored
 <code class="code">seq</code> can be used as a counter to request them all until
<code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  is returned.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> 
if the extension is not present, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fauthority_005fkey_005fid-1"><span>gnutls_x509_crt_get_authority_key_id<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fauthority_005fkey_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fauthority_005fkey_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fauthority_005fkey_005fid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_authority_key_id</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, void * <var class="var">id</var>, size_t * <var class="var">id_size</var>, unsigned int * <var class="var">critical</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fauthority_005fkey_005fid"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">id</var>: The place where the identifier will be copied
</p>
<p><var class="var">id_size</var>: Holds the size of the id field.
</p>
<p><var class="var">critical</var>: will be non-zero if the extension is marked as critical (may be null)
</p>
<p>This function will return the X.509v3 certificate authority&rsquo;s key
identifier.  This is obtained by the X.509 Authority Key
identifier extension field (2.5.29.35). Note that this function
only returns the keyIdentifier field of the extension and
<code class="code">GNUTLS_E_X509_UNSUPPORTED_EXTENSION</code> , if the extension contains
the name and serial number of the certificate. In that case
<code class="code">gnutls_x509_crt_get_authority_key_gn_serial()</code>  may be used.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> 
if the extension is not present, otherwise a negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fbasic_005fconstraints-1"><span>gnutls_x509_crt_get_basic_constraints<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fbasic_005fconstraints-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fbasic_005fconstraints"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fbasic_005fconstraints"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_basic_constraints</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, unsigned int * <var class="var">critical</var>, unsigned int * <var class="var">ca</var>, int * <var class="var">pathlen</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fbasic_005fconstraints"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">critical</var>: will be non-zero if the extension is marked as critical
</p>
<p><var class="var">ca</var>: pointer to output integer indicating CA status, may be NULL,
value is 1 if the certificate CA flag is set, 0 otherwise.
</p>
<p><var class="var">pathlen</var>: pointer to output integer indicating path length (may be
NULL), non-negative error codes indicate a present pathLenConstraint
field and the actual value, -1 indicate that the field is absent.
</p>
<p>This function will read the certificate&rsquo;s basic constraints, and
return the certificates CA status.  It reads the basicConstraints
X.509 extension (2.5.29.19).
</p>
<p><strong class="strong">Returns:</strong> If the certificate is a CA a positive value will be
returned, or (0) if the certificate does not have CA flag set.  A
negative error code may be returned in case of errors.  If the
certificate does not contain the basicConstraints extension
GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE will be returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fca_005fstatus-1"><span>gnutls_x509_crt_get_ca_status<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fca_005fstatus-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fca_005fstatus"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fca_005fstatus"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_ca_status</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, unsigned int * <var class="var">critical</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fca_005fstatus"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">critical</var>: will be non-zero if the extension is marked as critical
</p>
<p>This function will return certificates CA status, by reading the
basicConstraints X.509 extension (2.5.29.19). If the certificate is
a CA a positive value will be returned, or (0) if the certificate
does not have CA flag set.
</p>
<p>Use <code class="code">gnutls_x509_crt_get_basic_constraints()</code>  if you want to read the
pathLenConstraint field too.
</p>
<p><strong class="strong">Returns:</strong> If the certificate is a CA a positive value will be
returned, or (0) if the certificate does not have CA flag set.  A
negative error code may be returned in case of errors.  If the
certificate does not contain the basicConstraints extension
GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE will be returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fcrl_005fdist_005fpoints-1"><span>gnutls_x509_crt_get_crl_dist_points<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fcrl_005fdist_005fpoints-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fcrl_005fdist_005fpoints"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fcrl_005fdist_005fpoints"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_crl_dist_points</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, unsigned int <var class="var">seq</var>, void * <var class="var">san</var>, size_t * <var class="var">san_size</var>, unsigned int * <var class="var">reason_flags</var>, unsigned int * <var class="var">critical</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fcrl_005fdist_005fpoints"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">seq</var>: specifies the sequence number of the distribution point (0 for the first one, 1 for the second etc.)
</p>
<p><var class="var">san</var>: is the place where the distribution point will be copied to
</p>
<p><var class="var">san_size</var>: holds the size of ret.
</p>
<p><var class="var">reason_flags</var>: Revocation reasons. An ORed sequence of flags from <code class="code">gnutls_x509_crl_reason_flags_t</code> .
</p>
<p><var class="var">critical</var>: will be non-zero if the extension is marked as critical (may be null)
</p>
<p>This function retrieves the CRL distribution points (2.5.29.31),
contained in the given certificate in the X509v3 Certificate
Extensions.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  and updates  <code class="code">ret_size</code> if
 <code class="code">ret_size</code> is not enough to hold the distribution point, or the
type of the distribution point if everything was ok. The type is
one of the enumerated <code class="code">gnutls_x509_subject_alt_name_t</code> .  If the
certificate does not have an Alternative name with the specified
sequence number then <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  is
returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fdn-1"><span>gnutls_x509_crt_get_dn<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fdn-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fdn"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fdn"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_dn</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, char * <var class="var">buf</var>, size_t * <var class="var">buf_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fdn"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">buf</var>: a pointer to a structure to hold the name (may be null)
</p>
<p><var class="var">buf_size</var>: initially holds the size of  <code class="code">buf</code> 
</p>
<p>This function will copy the name of the Certificate in the provided
buffer. The name will be in the form &quot;C=xxxx,O=yyyy,CN=zzzz&quot; as
described in RFC4514. The output string will be ASCII or UTF-8
encoded, depending on the certificate data.
</p>
<p>The  <code class="code">buf</code> returned will be null terminated and the  <code class="code">buf_size</code> will account
for the trailing null. If  <code class="code">buf</code> is null then only the size will be filled.
</p>
<p>This function does not output a fully RFC4514 compliant string, if
that is required see <code class="code">gnutls_x509_crt_get_dn3()</code> .
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  if the provided buffer is not
long enough, and in that case the  <code class="code">buf_size</code> will be updated
with the required size. <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  if
the DN does not exist, or another error value on error. On success 0 is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fdn2-1"><span>gnutls_x509_crt_get_dn2<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fdn2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fdn2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fdn2-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_dn2</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, gnutls_datum_t * <var class="var">dn</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fdn2-1"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">dn</var>: a pointer to a structure to hold the name; must be freed using <code class="code">gnutls_free()</code> 
</p>
<p>This function will allocate buffer and copy the name of the Certificate.
The name will be in the form &quot;C=xxxx,O=yyyy,CN=zzzz&quot; as
described in RFC4514. The output string will be ASCII or UTF-8
encoded, depending on the certificate data.
</p>
<p>This function does not output a fully RFC4514 compliant string, if
that is required see <code class="code">gnutls_x509_crt_get_dn3()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.1.10
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fdn3-1"><span>gnutls_x509_crt_get_dn3<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fdn3-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fdn3"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fdn3"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_dn3</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, gnutls_datum_t * <var class="var">dn</var>, unsigned <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fdn3"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">dn</var>: a pointer to a structure to hold the name; must be freed using <code class="code">gnutls_free()</code> 
</p>
<p><var class="var">flags</var>: zero or <code class="code">GNUTLS_X509_DN_FLAG_COMPAT</code> 
</p>
<p>This function will allocate buffer and copy the name of the Certificate.
The name will be in the form &quot;C=xxxx,O=yyyy,CN=zzzz&quot; as
described in RFC4514. The output string will be ASCII or UTF-8
encoded, depending on the certificate data.
</p>
<p>When the flag <code class="code">GNUTLS_X509_DN_FLAG_COMPAT</code>  is specified, the output
format will match the format output by previous to 3.5.6 versions of GnuTLS
which was not not fully RFC4514-compliant.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.5.7
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fdn_005fby_005foid-1"><span>gnutls_x509_crt_get_dn_by_oid<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fdn_005fby_005foid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fdn_005fby_005foid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fdn_005fby_005foid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_dn_by_oid</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, const char * <var class="var">oid</var>, unsigned <var class="var">indx</var>, unsigned int <var class="var">raw_flag</var>, void * <var class="var">buf</var>, size_t * <var class="var">buf_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fdn_005fby_005foid"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">oid</var>: holds an Object Identified in null terminated string
</p>
<p><var class="var">indx</var>: In case multiple same OIDs exist in the RDN, this specifies which to send. Use (0) to get the first one.
</p>
<p><var class="var">raw_flag</var>: If non-zero returns the raw DER data of the DN part.
</p>
<p><var class="var">buf</var>: a pointer where the DN part will be copied (may be null).
</p>
<p><var class="var">buf_size</var>: initially holds the size of  <code class="code">buf</code> 
</p>
<p>This function will extract the part of the name of the Certificate
subject specified by the given OID. The output, if the raw flag is
not used, will be encoded as described in RFC4514. Thus a string
that is ASCII or UTF-8 encoded, depending on the certificate data.
</p>
<p>Some helper macros with popular OIDs can be found in gnutls/x509.h
If raw flag is (0), this function will only return known OIDs as
text. Other OIDs will be DER encoded, as described in RFC4514 &ndash;
in hex format with a &rsquo;#&rsquo; prefix.  You can check about known OIDs
using <code class="code">gnutls_x509_dn_oid_known()</code> .
</p>
<p>If  <code class="code">buf</code> is null then only the size will be filled. If the  <code class="code">raw_flag</code> is not specified the output is always null terminated, although the
 <code class="code">buf_size</code> will not include the null character.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  if the provided buffer is not
long enough, and in that case the  <code class="code">buf_size</code> will be updated with
the required size. <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  if there
are no data in the current index. On success 0 is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fdn_005foid-1"><span>gnutls_x509_crt_get_dn_oid<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fdn_005foid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fdn_005foid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fdn_005foid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_dn_oid</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, unsigned <var class="var">indx</var>, void * <var class="var">oid</var>, size_t * <var class="var">oid_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fdn_005foid"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">indx</var>: This specifies which OID to return. Use (0) to get the first one.
</p>
<p><var class="var">oid</var>: a pointer to a buffer to hold the OID (may be null)
</p>
<p><var class="var">oid_size</var>: initially holds the size of  <code class="code">oid</code> 
</p>
<p>This function will extract the OIDs of the name of the Certificate
subject specified by the given index.
</p>
<p>If  <code class="code">oid</code> is null then only the size will be filled. The  <code class="code">oid</code> returned will be null terminated, although  <code class="code">oid_size</code> will not
account for the trailing null.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  if the provided buffer is not
long enough, and in that case the  <code class="code">buf_size</code> will be updated with
the required size. <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  if there
are no data in the current index. On success 0 is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fexpiration_005ftime-1"><span>gnutls_x509_crt_get_expiration_time<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fexpiration_005ftime-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fexpiration_005ftime"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fexpiration_005ftime"><span class="category-def">Function: </span><span><code class="def-type">time_t</code> <strong class="def-name">gnutls_x509_crt_get_expiration_time</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fexpiration_005ftime"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p>This function will return the time this certificate was or will be
expired.
</p>
<p><strong class="strong">Returns:</strong> expiration time, or (time_t)-1 on error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fextension_005fby_005foid-1"><span>gnutls_x509_crt_get_extension_by_oid<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fextension_005fby_005foid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fextension_005fby_005foid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fextension_005fby_005foid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_extension_by_oid</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, const char * <var class="var">oid</var>, unsigned <var class="var">indx</var>, void * <var class="var">buf</var>, size_t * <var class="var">buf_size</var>, unsigned int * <var class="var">critical</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fextension_005fby_005foid"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">oid</var>: holds an Object Identified in null terminated string
</p>
<p><var class="var">indx</var>: In case multiple same OIDs exist in the extensions, this specifies which to send. Use (0) to get the first one.
</p>
<p><var class="var">buf</var>: a pointer to a structure to hold the name (may be null)
</p>
<p><var class="var">buf_size</var>: initially holds the size of  <code class="code">buf</code> 
</p>
<p><var class="var">critical</var>: will be non-zero if the extension is marked as critical
</p>
<p>This function will return the extension specified by the OID in the
certificate.  The extensions will be returned as binary data DER
encoded, in the provided buffer.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned. If the certificate does not
contain the specified extension
GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE will be returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fextension_005fby_005foid2-1"><span>gnutls_x509_crt_get_extension_by_oid2<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fextension_005fby_005foid2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fextension_005fby_005foid2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fextension_005fby_005foid2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_extension_by_oid2</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, const char * <var class="var">oid</var>, unsigned <var class="var">indx</var>, gnutls_datum_t * <var class="var">output</var>, unsigned int * <var class="var">critical</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fextension_005fby_005foid2"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">oid</var>: holds an Object Identified in null terminated string
</p>
<p><var class="var">indx</var>: In case multiple same OIDs exist in the extensions, this specifies which to send. Use (0) to get the first one.
</p>
<p><var class="var">output</var>: will hold the allocated extension data
</p>
<p><var class="var">critical</var>: will be non-zero if the extension is marked as critical
</p>
<p>This function will return the extension specified by the OID in the
certificate.  The extensions will be returned as binary data DER
encoded, in the provided buffer.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned. If the certificate does not
contain the specified extension
GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE will be returned.
</p>
<p><strong class="strong">Since:</strong> 3.3.8
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fextension_005fdata-1"><span>gnutls_x509_crt_get_extension_data<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fextension_005fdata-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fextension_005fdata"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fextension_005fdata"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_extension_data</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, unsigned <var class="var">indx</var>, void * <var class="var">data</var>, size_t * <var class="var">sizeof_data</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fextension_005fdata"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">indx</var>: Specifies which extension OID to send. Use (0) to get the first one.
</p>
<p><var class="var">data</var>: a pointer to a structure to hold the data (may be null)
</p>
<p><var class="var">sizeof_data</var>: initially holds the size of  <code class="code">data</code> 
</p>
<p>This function will return the requested extension data in the
certificate.  The extension data will be stored in the
provided buffer.
</p>
<p>Use <code class="code">gnutls_x509_crt_get_extension_info()</code>  to extract the OID and
critical flag.  Use <code class="code">gnutls_x509_crt_get_extension_by_oid()</code>  instead,
if you want to get data indexed by the extension OID rather than
sequence.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned.  If you have reached the
last extension available <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> 
will be returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fextension_005fdata2-1"><span>gnutls_x509_crt_get_extension_data2<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fextension_005fdata2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fextension_005fdata2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fextension_005fdata2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_extension_data2</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, unsigned <var class="var">indx</var>, gnutls_datum_t * <var class="var">data</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fextension_005fdata2"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">indx</var>: Specifies which extension OID to read. Use (0) to get the first one.
</p>
<p><var class="var">data</var>: will contain the extension DER-encoded data
</p>
<p>This function will return the requested by the index extension data in the
certificate.  The extension data will be allocated using
<code class="code">gnutls_malloc()</code> .
</p>
<p>Use <code class="code">gnutls_x509_crt_get_extension_info()</code>  to extract the OID.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned.  If you have reached the
last extension available <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> 
will be returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fextension_005finfo-1"><span>gnutls_x509_crt_get_extension_info<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fextension_005finfo-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fextension_005finfo"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fextension_005finfo"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_extension_info</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, unsigned <var class="var">indx</var>, void * <var class="var">oid</var>, size_t * <var class="var">oid_size</var>, unsigned int * <var class="var">critical</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fextension_005finfo"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">indx</var>: Specifies which extension OID to send. Use (0) to get the first one.
</p>
<p><var class="var">oid</var>: a pointer to a structure to hold the OID
</p>
<p><var class="var">oid_size</var>: initially holds the maximum size of  <code class="code">oid</code> , on return
holds actual size of  <code class="code">oid</code> .
</p>
<p><var class="var">critical</var>: output variable with critical flag, may be NULL.
</p>
<p>This function will return the requested extension OID in the
certificate, and the critical flag for it.  The extension OID will
be stored as a string in the provided buffer.  Use
<code class="code">gnutls_x509_crt_get_extension()</code>  to extract the data.
</p>
<p>If the buffer provided is not long enough to hold the output, then
 <code class="code">oid_size</code> is updated and <code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  will be
returned. The  <code class="code">oid</code> returned will be null terminated, although
 <code class="code">oid_size</code> will not account for the trailing null (the latter is not
true for GnuTLS prior to 3.6.0).
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned.  If you have reached the
last extension available <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> 
will be returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fextension_005foid-1"><span>gnutls_x509_crt_get_extension_oid<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fextension_005foid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fextension_005foid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fextension_005foid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_extension_oid</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, unsigned <var class="var">indx</var>, void * <var class="var">oid</var>, size_t * <var class="var">oid_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fextension_005foid"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">indx</var>: Specifies which extension OID to send. Use (0) to get the first one.
</p>
<p><var class="var">oid</var>: a pointer to a structure to hold the OID (may be null)
</p>
<p><var class="var">oid_size</var>: initially holds the size of  <code class="code">oid</code> 
</p>
<p>This function will return the requested extension OID in the certificate.
The extension OID will be stored as a string in the provided buffer.
</p>
<p>The  <code class="code">oid</code> returned will be null terminated, although  <code class="code">oid_size</code> will not
account for the trailing null.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned.  If you have reached the
last extension available <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> 
will be returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005ffingerprint-1"><span>gnutls_x509_crt_get_fingerprint<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005ffingerprint-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005ffingerprint"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005ffingerprint"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_fingerprint</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, gnutls_digest_algorithm_t <var class="var">algo</var>, void * <var class="var">buf</var>, size_t * <var class="var">buf_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005ffingerprint"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">algo</var>: is a digest algorithm
</p>
<p><var class="var">buf</var>: a pointer to a structure to hold the fingerprint (may be null)
</p>
<p><var class="var">buf_size</var>: initially holds the size of  <code class="code">buf</code> 
</p>
<p>This function will calculate and copy the certificate&rsquo;s fingerprint
in the provided buffer. The fingerprint is a hash of the DER-encoded
data of the certificate.
</p>
<p>If the buffer is null then only the size will be filled.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  if the provided buffer is
not long enough, and in that case the *buf_size will be updated
with the required size.  On success 0 is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005finhibit_005fanypolicy-1"><span>gnutls_x509_crt_get_inhibit_anypolicy<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005finhibit_005fanypolicy-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005finhibit_005fanypolicy"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005finhibit_005fanypolicy"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_inhibit_anypolicy</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, unsigned int * <var class="var">skipcerts</var>, unsigned int * <var class="var">critical</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005finhibit_005fanypolicy"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">skipcerts</var>: will hold the number of certificates after which anypolicy is no longer acceptable.
</p>
<p><var class="var">critical</var>: will be non-zero if the extension is marked as critical
</p>
<p>This function will return certificate&rsquo;s value of the SkipCerts, i.e.,
the Inhibit anyPolicy X.509 extension (2.5.29.54).
</p>
<p>The returned value is the number of additional certificates that
may appear in the path before the anyPolicy is no longer acceptable.
</p>
<p><strong class="strong">Returns:</strong> zero on success, or a negative error code in case of
parsing error.  If the certificate does not contain the Inhibit anyPolicy
extension <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  will be
returned.
</p>
<p><strong class="strong">Since:</strong> 3.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fissuer-1"><span>gnutls_x509_crt_get_issuer<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fissuer-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fissuer"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fissuer"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_issuer</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, gnutls_x509_dn_t * <var class="var">dn</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fissuer"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">dn</var>: output variable with pointer to uint8_t DN
</p>
<p>Return the Certificate&rsquo;s Issuer DN as a <code class="code">gnutls_x509_dn_t</code>  data type,
that can be decoded using <code class="code">gnutls_x509_dn_get_rdn_ava()</code> .
</p>
<p>Note that  <code class="code">dn</code> should be treated as constant. Because it points
into the  <code class="code">cert</code> object, you should not use  <code class="code">dn</code> after  <code class="code">cert</code> is
deallocated.
</p>
<p><strong class="strong">Returns:</strong> Returns 0 on success, or an error code.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fissuer_005falt_005fname-1"><span>gnutls_x509_crt_get_issuer_alt_name<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fissuer_005falt_005fname-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fissuer_005falt_005fname"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fissuer_005falt_005fname"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_issuer_alt_name</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, unsigned int <var class="var">seq</var>, void * <var class="var">ian</var>, size_t * <var class="var">ian_size</var>, unsigned int * <var class="var">critical</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fissuer_005falt_005fname"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">seq</var>: specifies the sequence number of the alt name (0 for the first one, 1 for the second etc.)
</p>
<p><var class="var">ian</var>: is the place where the alternative name will be copied to
</p>
<p><var class="var">ian_size</var>: holds the size of ian.
</p>
<p><var class="var">critical</var>: will be non-zero if the extension is marked as critical (may be null)
</p>
<p>This function retrieves the Issuer Alternative Name (2.5.29.18),
contained in the given certificate in the X509v3 Certificate
Extensions.
</p>
<p>When the SAN type is otherName, it will extract the data in the
otherName&rsquo;s value field, and <code class="code">GNUTLS_SAN_OTHERNAME</code>  is returned.
You may use <code class="code">gnutls_x509_crt_get_subject_alt_othername_oid()</code>  to get
the corresponding OID and the &quot;virtual&quot; SAN types (e.g.,
<code class="code">GNUTLS_SAN_OTHERNAME_XMPP</code> ).
</p>
<p>If an otherName OID is known, the data will be decoded.  Otherwise
the returned data will be DER encoded, and you will have to decode
it yourself.  Currently, only the RFC 3920 id-on-xmppAddr Issuer
AltName is recognized.
</p>
<p><strong class="strong">Returns:</strong> the alternative issuer name type on success, one of the
enumerated <code class="code">gnutls_x509_subject_alt_name_t</code> .  It will return
<code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  if  <code class="code">ian_size</code> is not large enough
to hold the value.  In that case  <code class="code">ian_size</code> will be updated with
the required size.  If the certificate does not have an
Alternative name with the specified sequence number then
<code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  is returned.
</p>
<p><strong class="strong">Since:</strong> 2.10.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fissuer_005falt_005fname2-1"><span>gnutls_x509_crt_get_issuer_alt_name2<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fissuer_005falt_005fname2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fissuer_005falt_005fname2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fissuer_005falt_005fname2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_issuer_alt_name2</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, unsigned int <var class="var">seq</var>, void * <var class="var">ian</var>, size_t * <var class="var">ian_size</var>, unsigned int * <var class="var">ian_type</var>, unsigned int * <var class="var">critical</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fissuer_005falt_005fname2"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">seq</var>: specifies the sequence number of the alt name (0 for the first one, 1 for the second etc.)
</p>
<p><var class="var">ian</var>: is the place where the alternative name will be copied to
</p>
<p><var class="var">ian_size</var>: holds the size of ret.
</p>
<p><var class="var">ian_type</var>: holds the type of the alternative name (one of gnutls_x509_subject_alt_name_t).
</p>
<p><var class="var">critical</var>: will be non-zero if the extension is marked as critical (may be null)
</p>
<p>This function will return the alternative names, contained in the
given certificate. It is the same as
<code class="code">gnutls_x509_crt_get_issuer_alt_name()</code>  except for the fact that it
will return the type of the alternative name in  <code class="code">ian_type</code> even if
the function fails for some reason (i.e.  the buffer provided is
not enough).
</p>
<p><strong class="strong">Returns:</strong> the alternative issuer name type on success, one of the
enumerated <code class="code">gnutls_x509_subject_alt_name_t</code> .  It will return
<code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  if  <code class="code">ian_size</code> is not large enough
to hold the value.  In that case  <code class="code">ian_size</code> will be updated with
the required size.  If the certificate does not have an
Alternative name with the specified sequence number then
<code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  is returned.
</p>
<p><strong class="strong">Since:</strong> 2.10.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fissuer_005falt_005fothername_005foid-1"><span>gnutls_x509_crt_get_issuer_alt_othername_oid<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fissuer_005falt_005fothername_005foid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fissuer_005falt_005fothername_005foid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fissuer_005falt_005fothername_005foid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_issuer_alt_othername_oid</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, unsigned int <var class="var">seq</var>, void * <var class="var">ret</var>, size_t * <var class="var">ret_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fissuer_005falt_005fothername_005foid"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">seq</var>: specifies the sequence number of the alt name (0 for the first one, 1 for the second etc.)
</p>
<p><var class="var">ret</var>: is the place where the otherName OID will be copied to
</p>
<p><var class="var">ret_size</var>: holds the size of ret.
</p>
<p>This function will extract the type OID of an otherName Subject
Alternative Name, contained in the given certificate, and return
the type as an enumerated element.
</p>
<p>If  <code class="code">oid</code> is null then only the size will be filled. The  <code class="code">oid</code> returned will be null terminated, although  <code class="code">oid_size</code> will not
account for the trailing null.
</p>
<p>This function is only useful if
<code class="code">gnutls_x509_crt_get_issuer_alt_name()</code>  returned
<code class="code">GNUTLS_SAN_OTHERNAME</code> .
</p>
<p><strong class="strong">Returns:</strong> the alternative issuer name type on success, one of the
enumerated gnutls_x509_subject_alt_name_t.  For supported OIDs, it
will return one of the virtual (GNUTLS_SAN_OTHERNAME_*) types,
e.g. <code class="code">GNUTLS_SAN_OTHERNAME_XMPP</code> , and <code class="code">GNUTLS_SAN_OTHERNAME</code>  for
unknown OIDs.  It will return <code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  if
 <code class="code">ret_size</code> is not large enough to hold the value.  In that case
 <code class="code">ret_size</code> will be updated with the required size.  If the
certificate does not have an Alternative name with the specified
sequence number and with the otherName type then
<code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  is returned.
</p>
<p><strong class="strong">Since:</strong> 2.10.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn-1"><span>gnutls_x509_crt_get_issuer_dn<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_issuer_dn</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, char * <var class="var">buf</var>, size_t * <var class="var">buf_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">buf</var>: a pointer to a structure to hold the name (may be null)
</p>
<p><var class="var">buf_size</var>: initially holds the size of  <code class="code">buf</code> 
</p>
<p>This function will copy the name of the Certificate issuer in the
provided buffer. The name will be in the form
&quot;C=xxxx,O=yyyy,CN=zzzz&quot; as described in RFC4514. The output string
will be ASCII or UTF-8 encoded, depending on the certificate data.
</p>
<p>If  <code class="code">buf</code> is null then only the size will be filled.
</p>
<p>This function does not output a fully RFC4514 compliant string, if
that is required see <code class="code">gnutls_x509_crt_get_issuer_dn3()</code> .
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  if the provided buffer is not
long enough, and in that case the  <code class="code">buf_size</code> will be updated
with the required size. <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  if
the DN does not exist, or another error value on error. On success 0 is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn2-1"><span>gnutls_x509_crt_get_issuer_dn2<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_issuer_dn2</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, gnutls_datum_t * <var class="var">dn</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn2"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">dn</var>: a pointer to a structure to hold the name; must be freed using <code class="code">gnutls_free()</code> 
</p>
<p>This function will allocate buffer and copy the name of issuer of the Certificate.
The name will be in the form &quot;C=xxxx,O=yyyy,CN=zzzz&quot; as
described in RFC4514. The output string will be ASCII or UTF-8
encoded, depending on the certificate data.
</p>
<p>This function does not output a fully RFC4514 compliant string, if
that is required see <code class="code">gnutls_x509_crt_get_issuer_dn3()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.1.10
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn3-1"><span>gnutls_x509_crt_get_issuer_dn3<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn3-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn3"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn3"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_issuer_dn3</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, gnutls_datum_t * <var class="var">dn</var>, unsigned <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn3"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">dn</var>: a pointer to a structure to hold the name; must be freed using <code class="code">gnutls_free()</code> 
</p>
<p><var class="var">flags</var>: zero or <code class="code">GNUTLS_X509_DN_FLAG_COMPAT</code> 
</p>
<p>This function will allocate buffer and copy the name of issuer of the Certificate.
The name will be in the form &quot;C=xxxx,O=yyyy,CN=zzzz&quot; as
described in RFC4514. The output string will be ASCII or UTF-8
encoded, depending on the certificate data.
</p>
<p>When the flag <code class="code">GNUTLS_X509_DN_FLAG_COMPAT</code>  is specified, the output
format will match the format output by previous to 3.5.6 versions of GnuTLS
which was not not fully RFC4514-compliant.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.5.7
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn_005fby_005foid-1"><span>gnutls_x509_crt_get_issuer_dn_by_oid<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn_005fby_005foid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn_005fby_005foid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn_005fby_005foid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_issuer_dn_by_oid</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, const char * <var class="var">oid</var>, unsigned <var class="var">indx</var>, unsigned int <var class="var">raw_flag</var>, void * <var class="var">buf</var>, size_t * <var class="var">buf_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn_005fby_005foid"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">oid</var>: holds an Object Identified in null terminated string
</p>
<p><var class="var">indx</var>: In case multiple same OIDs exist in the RDN, this specifies which to send. Use (0) to get the first one.
</p>
<p><var class="var">raw_flag</var>: If non-zero returns the raw DER data of the DN part.
</p>
<p><var class="var">buf</var>: a pointer to a structure to hold the name (may be null)
</p>
<p><var class="var">buf_size</var>: initially holds the size of  <code class="code">buf</code> 
</p>
<p>This function will extract the part of the name of the Certificate
issuer specified by the given OID. The output, if the raw flag is not
used, will be encoded as described in RFC4514. Thus a string that is
ASCII or UTF-8 encoded, depending on the certificate data.
</p>
<p>Some helper macros with popular OIDs can be found in gnutls/x509.h
If raw flag is (0), this function will only return known OIDs as
text. Other OIDs will be DER encoded, as described in RFC4514 &ndash;
in hex format with a &rsquo;#&rsquo; prefix.  You can check about known OIDs
using <code class="code">gnutls_x509_dn_oid_known()</code> .
</p>
<p>If  <code class="code">buf</code> is null then only the size will be filled. If the  <code class="code">raw_flag</code> is not specified the output is always null terminated, although the
 <code class="code">buf_size</code> will not include the null character.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  if the provided buffer is not
long enough, and in that case the  <code class="code">buf_size</code> will be updated with
the required size. <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  if there
are no data in the current index. On success 0 is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn_005foid-1"><span>gnutls_x509_crt_get_issuer_dn_oid<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn_005foid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn_005foid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn_005foid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_issuer_dn_oid</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, unsigned <var class="var">indx</var>, void * <var class="var">oid</var>, size_t * <var class="var">oid_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn_005foid"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">indx</var>: This specifies which OID to return. Use (0) to get the first one.
</p>
<p><var class="var">oid</var>: a pointer to a buffer to hold the OID (may be null)
</p>
<p><var class="var">oid_size</var>: initially holds the size of  <code class="code">oid</code> 
</p>
<p>This function will extract the OIDs of the name of the Certificate
issuer specified by the given index.
</p>
<p>If  <code class="code">oid</code> is null then only the size will be filled. The  <code class="code">oid</code> returned will be null terminated, although  <code class="code">oid_size</code> will not
account for the trailing null.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  if the provided buffer is not
long enough, and in that case the  <code class="code">buf_size</code> will be updated with
the required size. <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  if there
are no data in the current index. On success 0 is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fissuer_005funique_005fid-1"><span>gnutls_x509_crt_get_issuer_unique_id<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fissuer_005funique_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fissuer_005funique_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fissuer_005funique_005fid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_issuer_unique_id</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, char * <var class="var">buf</var>, size_t * <var class="var">buf_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fissuer_005funique_005fid"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: Holds the certificate
</p>
<p><var class="var">buf</var>: user allocated memory buffer, will hold the unique id
</p>
<p><var class="var">buf_size</var>: size of user allocated memory buffer (on input), will hold
actual size of the unique ID on return.
</p>
<p>This function will extract the issuerUniqueID value (if present) for
the given certificate.
</p>
<p>If the user allocated memory buffer is not large enough to hold the
full subjectUniqueID, then a GNUTLS_E_SHORT_MEMORY_BUFFER error will be
returned, and buf_size will be set to the actual length.
</p>
<p>This function had a bug prior to 3.4.8 that prevented the setting
of <code class="code">NULL</code>   <code class="code">buf</code> to discover the  <code class="code">buf_size</code> . To use this function safely
with the older versions the  <code class="code">buf</code> must be a valid buffer that can hold
at least a single byte if  <code class="code">buf_size</code> is zero.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fkey_005fid-1"><span>gnutls_x509_crt_get_key_id<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fkey_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fkey_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fkey_005fid-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_key_id</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, unsigned int <var class="var">flags</var>, unsigned char * <var class="var">output_data</var>, size_t * <var class="var">output_data_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fkey_005fid-1"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: Holds the certificate
</p>
<p><var class="var">flags</var>: should be one of the flags from <code class="code">gnutls_keyid_flags_t</code> 
</p>
<p><var class="var">output_data</var>: will contain the key ID
</p>
<p><var class="var">output_data_size</var>: holds the size of output_data (and will be
replaced by the actual size of parameters)
</p>
<p>This function will return a unique ID that depends on the public
key parameters. This ID can be used in checking whether a
certificate corresponds to the given private key.
</p>
<p>If the buffer provided is not long enough to hold the output, then
*output_data_size is updated and GNUTLS_E_SHORT_MEMORY_BUFFER will
be returned.  The output will normally be a SHA-1 hash output,
which is 20 bytes.
</p>
<p><strong class="strong">Returns:</strong> In case of failure a negative error code will be
returned, and 0 on success.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fkey_005fpurpose_005foid-1"><span>gnutls_x509_crt_get_key_purpose_oid<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fkey_005fpurpose_005foid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fkey_005fpurpose_005foid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fkey_005fpurpose_005foid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_key_purpose_oid</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, unsigned <var class="var">indx</var>, void * <var class="var">oid</var>, size_t * <var class="var">oid_size</var>, unsigned int * <var class="var">critical</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fkey_005fpurpose_005foid"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">indx</var>: This specifies which OID to return. Use (0) to get the first one.
</p>
<p><var class="var">oid</var>: a pointer to a buffer to hold the OID (may be null)
</p>
<p><var class="var">oid_size</var>: initially holds the size of  <code class="code">oid</code> 
</p>
<p><var class="var">critical</var>: output flag to indicate criticality of extension
</p>
<p>This function will extract the key purpose OIDs of the Certificate
specified by the given index.  These are stored in the Extended Key
Usage extension (2.5.29.37) See the GNUTLS_KP_* definitions for
human readable names.
</p>
<p>If  <code class="code">oid</code> is null then only the size will be filled. The  <code class="code">oid</code> returned will be null terminated, although  <code class="code">oid_size</code> will not
account for the trailing null.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  if the provided buffer is
not long enough, and in that case the *oid_size will be updated
with the required size.  On success 0 is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fkey_005fusage-1"><span>gnutls_x509_crt_get_key_usage<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fkey_005fusage-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fkey_005fusage"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fkey_005fusage"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_key_usage</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, unsigned int * <var class="var">key_usage</var>, unsigned int * <var class="var">critical</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fkey_005fusage"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">key_usage</var>: where the key usage bits will be stored
</p>
<p><var class="var">critical</var>: will be non-zero if the extension is marked as critical
</p>
<p>This function will return certificate&rsquo;s key usage, by reading the
keyUsage X.509 extension (2.5.29.15). The key usage value will ORed
values of the: <code class="code">GNUTLS_KEY_DIGITAL_SIGNATURE</code> ,
<code class="code">GNUTLS_KEY_NON_REPUDIATION</code> , <code class="code">GNUTLS_KEY_KEY_ENCIPHERMENT</code> ,
<code class="code">GNUTLS_KEY_DATA_ENCIPHERMENT</code> , <code class="code">GNUTLS_KEY_KEY_AGREEMENT</code> ,
<code class="code">GNUTLS_KEY_KEY_CERT_SIGN</code> , <code class="code">GNUTLS_KEY_CRL_SIGN</code> ,
<code class="code">GNUTLS_KEY_ENCIPHER_ONLY</code> , <code class="code">GNUTLS_KEY_DECIPHER_ONLY</code> .
</p>
<p><strong class="strong">Returns:</strong> zero on success, or a negative error code in case of
parsing error.  If the certificate does not contain the keyUsage
extension <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  will be
returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fname_005fconstraints-1"><span>gnutls_x509_crt_get_name_constraints<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fname_005fconstraints-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fname_005fconstraints"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fname_005fconstraints"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_name_constraints</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, gnutls_x509_name_constraints_t <var class="var">nc</var>, unsigned int <var class="var">flags</var>, unsigned int * <var class="var">critical</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fname_005fconstraints"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">nc</var>: The nameconstraints intermediate type
</p>
<p><var class="var">flags</var>: zero or <code class="code">GNUTLS_EXT_FLAG_APPEND</code> 
</p>
<p><var class="var">critical</var>: the extension status
</p>
<p>This function will return an intermediate type containing
the name constraints of the provided CA certificate. That
structure can be used in combination with <code class="code">gnutls_x509_name_constraints_check()</code> 
to verify whether a server&rsquo;s name is in accordance with the constraints.
</p>
<p>When the  <code class="code">flags</code> is set to <code class="code">GNUTLS_EXT_FLAG_APPEND</code> ,
then if the  <code class="code">nc</code> structure is empty this function will behave
identically as if the flag was not set.
Otherwise if there are elements in the  <code class="code">nc</code> structure then the
constraints will be merged with the existing constraints following
RFC5280 p6.1.4 (excluded constraints will be appended, permitted
will be intersected).
</p>
<p>Note that  <code class="code">nc</code> must be initialized prior to calling this function.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> 
if the extension is not present, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fpk_005falgorithm-1"><span>gnutls_x509_crt_get_pk_algorithm<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fpk_005falgorithm-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fpk_005falgorithm"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fpk_005falgorithm"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_pk_algorithm</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, unsigned int * <var class="var">bits</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fpk_005falgorithm"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">bits</var>: if bits is non null it will hold the size of the parameters&rsquo; in bits
</p>
<p>This function will return the public key algorithm of an X.509
certificate.
</p>
<p>If bits is non null, it should have enough size to hold the parameters
size in bits. For RSA the bits returned is the modulus.
For DSA the bits returned are of the public
exponent.
</p>
<p>Unknown/unsupported algorithms are mapped to <code class="code">GNUTLS_PK_UNKNOWN</code> .
</p>
<p><strong class="strong">Returns:</strong> a member of the <code class="code">gnutls_pk_algorithm_t</code>  enumeration on
success, or a negative error code on error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fpk_005fdsa_005fraw-1"><span>gnutls_x509_crt_get_pk_dsa_raw<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fpk_005fdsa_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fpk_005fdsa_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fpk_005fdsa_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_pk_dsa_raw</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, gnutls_datum_t * <var class="var">p</var>, gnutls_datum_t * <var class="var">q</var>, gnutls_datum_t * <var class="var">g</var>, gnutls_datum_t * <var class="var">y</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fpk_005fdsa_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: Holds the certificate
</p>
<p><var class="var">p</var>: will hold the p
</p>
<p><var class="var">q</var>: will hold the q
</p>
<p><var class="var">g</var>: will hold the g
</p>
<p><var class="var">y</var>: will hold the y
</p>
<p>This function will export the DSA public key&rsquo;s parameters found in
the given certificate.  The new parameters will be allocated using
<code class="code">gnutls_malloc()</code>  and will be stored in the appropriate datum.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fpk_005fecc_005fraw-1"><span>gnutls_x509_crt_get_pk_ecc_raw<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fpk_005fecc_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fpk_005fecc_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fpk_005fecc_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_pk_ecc_raw</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, gnutls_ecc_curve_t * <var class="var">curve</var>, gnutls_datum_t * <var class="var">x</var>, gnutls_datum_t * <var class="var">y</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fpk_005fecc_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: Holds the certificate
</p>
<p><var class="var">curve</var>: will hold the curve
</p>
<p><var class="var">x</var>: will hold the x-coordinate
</p>
<p><var class="var">y</var>: will hold the y-coordinate
</p>
<p>This function will export the ECC public key&rsquo;s parameters found in
the given certificate.  The new parameters will be allocated using
<code class="code">gnutls_malloc()</code>  and will be stored in the appropriate datum.
</p>
<p>In EdDSA curves the  <code class="code">y</code> parameter will be <code class="code">NULL</code>  and the other parameters
will be in the native format for the curve.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.4.1
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fpk_005fgost_005fraw-1"><span>gnutls_x509_crt_get_pk_gost_raw<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fpk_005fgost_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fpk_005fgost_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fpk_005fgost_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_pk_gost_raw</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, gnutls_ecc_curve_t * <var class="var">curve</var>, gnutls_digest_algorithm_t * <var class="var">digest</var>, gnutls_gost_paramset_t * <var class="var">paramset</var>, gnutls_datum_t * <var class="var">x</var>, gnutls_datum_t * <var class="var">y</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fpk_005fgost_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: Holds the certificate
</p>
<p><var class="var">curve</var>: will hold the curve
</p>
<p><var class="var">digest</var>: will hold the digest
</p>
<p><var class="var">paramset</var>: will hold the GOST parameter set ID
</p>
<p><var class="var">x</var>: will hold the x-coordinate
</p>
<p><var class="var">y</var>: will hold the y-coordinate
</p>
<p>This function will export the GOST public key&rsquo;s parameters found in
the given certificate.  The new parameters will be allocated using
<code class="code">gnutls_malloc()</code>  and will be stored in the appropriate datum.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.6.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fpk_005foid-1"><span>gnutls_x509_crt_get_pk_oid<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fpk_005foid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fpk_005foid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fpk_005foid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_pk_oid</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, char * <var class="var">oid</var>, size_t * <var class="var">oid_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fpk_005foid"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">oid</var>: a pointer to a buffer to hold the OID (may be null)
</p>
<p><var class="var">oid_size</var>: initially holds the size of  <code class="code">oid</code> 
</p>
<p>This function will return the OID of the public key algorithm
on that certificate. This is function
is useful in the case <code class="code">gnutls_x509_crt_get_pk_algorithm()</code> 
returned <code class="code">GNUTLS_PK_UNKNOWN</code> .
</p>
<p><strong class="strong">Returns:</strong> zero or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 3.5.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fpk_005frsa_005fraw-1"><span>gnutls_x509_crt_get_pk_rsa_raw<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fpk_005frsa_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fpk_005frsa_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fpk_005frsa_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_pk_rsa_raw</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, gnutls_datum_t * <var class="var">m</var>, gnutls_datum_t * <var class="var">e</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fpk_005frsa_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: Holds the certificate
</p>
<p><var class="var">m</var>: will hold the modulus
</p>
<p><var class="var">e</var>: will hold the public exponent
</p>
<p>This function will export the RSA public key&rsquo;s parameters found in
the given structure.  The new parameters will be allocated using
<code class="code">gnutls_malloc()</code>  and will be stored in the appropriate datum.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fpolicy-1"><span>gnutls_x509_crt_get_policy<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fpolicy-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fpolicy"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fpolicy"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_policy</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, unsigned <var class="var">indx</var>, struct gnutls_x509_policy_st * <var class="var">policy</var>, unsigned int * <var class="var">critical</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fpolicy"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">indx</var>: This specifies which policy to return. Use (0) to get the first one.
</p>
<p><var class="var">policy</var>: A pointer to a policy structure.
</p>
<p><var class="var">critical</var>: will be non-zero if the extension is marked as critical
</p>
<p>This function will extract the certificate policy (extension 2.5.29.32)
specified by the given index.
</p>
<p>The policy returned by this function must be deinitialized by using
<code class="code">gnutls_x509_policy_release()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> 
if the extension is not present, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.1.5
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fprivate_005fkey_005fusage_005fperiod-1"><span>gnutls_x509_crt_get_private_key_usage_period<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fprivate_005fkey_005fusage_005fperiod-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fprivate_005fkey_005fusage_005fperiod"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fprivate_005fkey_005fusage_005fperiod"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_private_key_usage_period</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, time_t * <var class="var">activation</var>, time_t * <var class="var">expiration</var>, unsigned int * <var class="var">critical</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fprivate_005fkey_005fusage_005fperiod"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">activation</var>: The activation time
</p>
<p><var class="var">expiration</var>: The expiration time
</p>
<p><var class="var">critical</var>: the extension status
</p>
<p>This function will return the expiration and activation
times of the private key of the certificate. It relies on
the PKIX extension 2.5.29.16 being present.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> 
if the extension is not present, otherwise a negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fproxy-1"><span>gnutls_x509_crt_get_proxy<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fproxy-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fproxy"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fproxy"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_proxy</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, unsigned int * <var class="var">critical</var>, int * <var class="var">pathlen</var>, char ** <var class="var">policyLanguage</var>, char ** <var class="var">policy</var>, size_t * <var class="var">sizeof_policy</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fproxy"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">critical</var>: will be non-zero if the extension is marked as critical
</p>
<p><var class="var">pathlen</var>: pointer to output integer indicating path length (may be
NULL), non-negative error codes indicate a present pCPathLenConstraint
field and the actual value, -1 indicate that the field is absent.
</p>
<p><var class="var">policyLanguage</var>: output variable with OID of policy language
</p>
<p><var class="var">policy</var>: output variable with policy data
</p>
<p><var class="var">sizeof_policy</var>: output variable size of policy data
</p>
<p>This function will get information from a proxy certificate.  It
reads the ProxyCertInfo X.509 extension (1.3.6.1.5.5.7.1.14).
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fraw_005fdn-1"><span>gnutls_x509_crt_get_raw_dn<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fraw_005fdn-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fraw_005fdn"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fraw_005fdn"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_raw_dn</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, gnutls_datum_t * <var class="var">dn</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fraw_005fdn"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">dn</var>: will hold the starting point of the DN
</p>
<p>This function will return a pointer to the DER encoded DN structure and
the length. This points to allocated data that must be free&rsquo;d using <code class="code">gnutls_free()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value. or a negative error code on error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fraw_005fissuer_005fdn-1"><span>gnutls_x509_crt_get_raw_issuer_dn<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fraw_005fissuer_005fdn-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fraw_005fissuer_005fdn"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fraw_005fissuer_005fdn"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_raw_issuer_dn</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, gnutls_datum_t * <var class="var">dn</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fraw_005fissuer_005fdn"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">dn</var>: will hold the starting point of the DN
</p>
<p>This function will return a pointer to the DER encoded DN structure
and the length. This points to allocated data that must be free&rsquo;d using <code class="code">gnutls_free()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.or a negative error code on error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fserial-1"><span>gnutls_x509_crt_get_serial<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fserial-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fserial"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fserial"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_serial</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, void * <var class="var">result</var>, size_t * <var class="var">result_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fserial"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">result</var>: The place where the serial number will be copied
</p>
<p><var class="var">result_size</var>: Holds the size of the result field.
</p>
<p>This function will return the X.509 certificate&rsquo;s serial number.
This is obtained by the X509 Certificate serialNumber field. Serial
is not always a 32 or 64bit number. Some CAs use large serial
numbers, thus it may be wise to handle it as something uint8_t.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fsignature-1"><span>gnutls_x509_crt_get_signature<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fsignature-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fsignature"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fsignature"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_signature</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, char * <var class="var">sig</var>, size_t * <var class="var">sig_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fsignature"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">sig</var>: a pointer where the signature part will be copied (may be null).
</p>
<p><var class="var">sig_size</var>: initially holds the size of  <code class="code">sig</code> 
</p>
<p>This function will extract the signature field of a certificate.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fsignature_005falgorithm-1"><span>gnutls_x509_crt_get_signature_algorithm<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fsignature_005falgorithm-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fsignature_005falgorithm"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fsignature_005falgorithm"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_signature_algorithm</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fsignature_005falgorithm"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p>This function will return a value of the <code class="code">gnutls_sign_algorithm_t</code> 
enumeration that is the signature algorithm that has been used to
sign this certificate.
</p>
<p>Since 3.6.0 this function never returns a negative error code.
Error cases and unknown/unsupported signature algorithms are
mapped to <code class="code">GNUTLS_SIGN_UNKNOWN</code> .
</p>
<p><strong class="strong">Returns:</strong> a <code class="code">gnutls_sign_algorithm_t</code>  value
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fsignature_005foid-1"><span>gnutls_x509_crt_get_signature_oid<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fsignature_005foid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fsignature_005foid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fsignature_005foid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_signature_oid</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, char * <var class="var">oid</var>, size_t * <var class="var">oid_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fsignature_005foid"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">oid</var>: a pointer to a buffer to hold the OID (may be null)
</p>
<p><var class="var">oid_size</var>: initially holds the size of  <code class="code">oid</code> 
</p>
<p>This function will return the OID of the signature algorithm
that has been used to sign this certificate. This is function
is useful in the case <code class="code">gnutls_x509_crt_get_signature_algorithm()</code> 
returned <code class="code">GNUTLS_SIGN_UNKNOWN</code> .
</p>
<p><strong class="strong">Returns:</strong> zero or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 3.5.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fspki-1"><span>gnutls_x509_crt_get_spki<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fspki-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fspki"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fspki"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_spki</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, gnutls_x509_spki_t <var class="var">spki</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fspki"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: a certificate of type <code class="code">gnutls_x509_crt_t</code> 
</p>
<p><var class="var">spki</var>: a SubjectPublicKeyInfo structure of type <code class="code">gnutls_x509_spki_t</code> 
</p>
<p><var class="var">flags</var>: must be zero
</p>
<p>This function will return the public key information of an X.509
certificate. The provided  <code class="code">spki</code> must be initialized.
</p>
<p><strong class="strong">Since:</strong> 3.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fsubject-1"><span>gnutls_x509_crt_get_subject<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fsubject-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fsubject"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fsubject"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_subject</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, gnutls_x509_dn_t * <var class="var">dn</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fsubject"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">dn</var>: output variable with pointer to uint8_t DN.
</p>
<p>Return the Certificate&rsquo;s Subject DN as a <code class="code">gnutls_x509_dn_t</code>  data type,
that can be decoded using <code class="code">gnutls_x509_dn_get_rdn_ava()</code> .
</p>
<p>Note that  <code class="code">dn</code> should be treated as constant. Because it points
into the  <code class="code">cert</code> object, you should not use  <code class="code">dn</code> after  <code class="code">cert</code> is
deallocated.
</p>
<p><strong class="strong">Returns:</strong> Returns 0 on success, or an error code.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fsubject_005falt_005fname-1"><span>gnutls_x509_crt_get_subject_alt_name<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fsubject_005falt_005fname-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fsubject_005falt_005fname"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fsubject_005falt_005fname"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_subject_alt_name</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, unsigned int <var class="var">seq</var>, void * <var class="var">san</var>, size_t * <var class="var">san_size</var>, unsigned int * <var class="var">critical</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fsubject_005falt_005fname"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">seq</var>: specifies the sequence number of the alt name (0 for the first one, 1 for the second etc.)
</p>
<p><var class="var">san</var>: is the place where the alternative name will be copied to
</p>
<p><var class="var">san_size</var>: holds the size of san.
</p>
<p><var class="var">critical</var>: will be non-zero if the extension is marked as critical (may be null)
</p>
<p>This function retrieves the Alternative Name (2.5.29.17), contained
in the given certificate in the X509v3 Certificate Extensions.
</p>
<p>When the SAN type is otherName, it will extract the data in the
otherName&rsquo;s value field, and <code class="code">GNUTLS_SAN_OTHERNAME</code>  is returned.
You may use <code class="code">gnutls_x509_crt_get_subject_alt_othername_oid()</code>  to get
the corresponding OID and the &quot;virtual&quot; SAN types (e.g.,
<code class="code">GNUTLS_SAN_OTHERNAME_XMPP</code> ).
</p>
<p>If an otherName OID is known, the data will be decoded.  Otherwise
the returned data will be DER encoded, and you will have to decode
it yourself.  Currently, only the RFC 3920 id-on-xmppAddr SAN is
recognized.
</p>
<p><strong class="strong">Returns:</strong> the alternative subject name type on success, one of the
enumerated <code class="code">gnutls_x509_subject_alt_name_t</code> .  It will return
<code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  if  <code class="code">san_size</code> is not large enough to
hold the value.  In that case  <code class="code">san_size</code> will be updated with the
required size.  If the certificate does not have an Alternative
name with the specified sequence number then
<code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fsubject_005falt_005fname2-1"><span>gnutls_x509_crt_get_subject_alt_name2<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fsubject_005falt_005fname2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fsubject_005falt_005fname2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fsubject_005falt_005fname2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_subject_alt_name2</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, unsigned int <var class="var">seq</var>, void * <var class="var">san</var>, size_t * <var class="var">san_size</var>, unsigned int * <var class="var">san_type</var>, unsigned int * <var class="var">critical</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fsubject_005falt_005fname2"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">seq</var>: specifies the sequence number of the alt name (0 for the first one, 1 for the second etc.)
</p>
<p><var class="var">san</var>: is the place where the alternative name will be copied to
</p>
<p><var class="var">san_size</var>: holds the size of ret.
</p>
<p><var class="var">san_type</var>: holds the type of the alternative name (one of gnutls_x509_subject_alt_name_t).
</p>
<p><var class="var">critical</var>: will be non-zero if the extension is marked as critical (may be null)
</p>
<p>This function will return the alternative names, contained in the
given certificate. It is the same as
<code class="code">gnutls_x509_crt_get_subject_alt_name()</code>  except for the fact that it
will return the type of the alternative name in  <code class="code">san_type</code> even if
the function fails for some reason (i.e.  the buffer provided is
not enough).
</p>
<p><strong class="strong">Returns:</strong> the alternative subject name type on success, one of the
enumerated <code class="code">gnutls_x509_subject_alt_name_t</code> .  It will return
<code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  if  <code class="code">san_size</code> is not large enough
to hold the value.  In that case  <code class="code">san_size</code> will be updated with
the required size.  If the certificate does not have an
Alternative name with the specified sequence number then
<code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fsubject_005falt_005fothername_005foid-1"><span>gnutls_x509_crt_get_subject_alt_othername_oid<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fsubject_005falt_005fothername_005foid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fsubject_005falt_005fothername_005foid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fsubject_005falt_005fothername_005foid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_subject_alt_othername_oid</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, unsigned int <var class="var">seq</var>, void * <var class="var">oid</var>, size_t * <var class="var">oid_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fsubject_005falt_005fothername_005foid"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">seq</var>: specifies the sequence number of the alt name (0 for the first one, 1 for the second etc.)
</p>
<p><var class="var">oid</var>: is the place where the otherName OID will be copied to
</p>
<p><var class="var">oid_size</var>: holds the size of ret.
</p>
<p>This function will extract the type OID of an otherName Subject
Alternative Name, contained in the given certificate, and return
the type as an enumerated element.
</p>
<p>This function is only useful if
<code class="code">gnutls_x509_crt_get_subject_alt_name()</code>  returned
<code class="code">GNUTLS_SAN_OTHERNAME</code> .
</p>
<p>If  <code class="code">oid</code> is null then only the size will be filled. The  <code class="code">oid</code> returned will be null terminated, although  <code class="code">oid_size</code> will not
account for the trailing null.
</p>
<p><strong class="strong">Returns:</strong> the alternative subject name type on success, one of the
enumerated gnutls_x509_subject_alt_name_t.  For supported OIDs, it
will return one of the virtual (GNUTLS_SAN_OTHERNAME_*) types,
e.g. <code class="code">GNUTLS_SAN_OTHERNAME_XMPP</code> , and <code class="code">GNUTLS_SAN_OTHERNAME</code>  for
unknown OIDs.  It will return <code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  if
 <code class="code">ian_size</code> is not large enough to hold the value.  In that case
 <code class="code">ian_size</code> will be updated with the required size.  If the
certificate does not have an Alternative name with the specified
sequence number and with the otherName type then
<code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fsubject_005fkey_005fid-1"><span>gnutls_x509_crt_get_subject_key_id<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fsubject_005fkey_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fsubject_005fkey_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fsubject_005fkey_005fid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_subject_key_id</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, void * <var class="var">ret</var>, size_t * <var class="var">ret_size</var>, unsigned int * <var class="var">critical</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fsubject_005fkey_005fid"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">ret</var>: The place where the identifier will be copied
</p>
<p><var class="var">ret_size</var>: Holds the size of the result field.
</p>
<p><var class="var">critical</var>: will be non-zero if the extension is marked as critical (may be null)
</p>
<p>This function will return the X.509v3 certificate&rsquo;s subject key
identifier.  This is obtained by the X.509 Subject Key identifier
extension field (2.5.29.14).
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> 
if the extension is not present, otherwise a negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fsubject_005funique_005fid-1"><span>gnutls_x509_crt_get_subject_unique_id<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fsubject_005funique_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fsubject_005funique_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fsubject_005funique_005fid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_subject_unique_id</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, char * <var class="var">buf</var>, size_t * <var class="var">buf_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fsubject_005funique_005fid"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: Holds the certificate
</p>
<p><var class="var">buf</var>: user allocated memory buffer, will hold the unique id
</p>
<p><var class="var">buf_size</var>: size of user allocated memory buffer (on input), will hold
actual size of the unique ID on return.
</p>
<p>This function will extract the subjectUniqueID value (if present) for
the given certificate.
</p>
<p>If the user allocated memory buffer is not large enough to hold the
full subjectUniqueID, then a GNUTLS_E_SHORT_MEMORY_BUFFER error will be
returned, and buf_size will be set to the actual length.
</p>
<p>This function had a bug prior to 3.4.8 that prevented the setting
of <code class="code">NULL</code>   <code class="code">buf</code> to discover the  <code class="code">buf_size</code> . To use this function safely
with the older versions the  <code class="code">buf</code> must be a valid buffer that can hold
at least a single byte if  <code class="code">buf_size</code> is zero.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005ftlsfeatures-1"><span>gnutls_x509_crt_get_tlsfeatures<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005ftlsfeatures-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005ftlsfeatures"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005ftlsfeatures"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_tlsfeatures</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, gnutls_x509_tlsfeatures_t <var class="var">features</var>, unsigned int <var class="var">flags</var>, unsigned int * <var class="var">critical</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005ftlsfeatures"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: A X.509 certificate
</p>
<p><var class="var">features</var>: If the function succeeds, the
features will be stored in this variable.
</p>
<p><var class="var">flags</var>: zero or <code class="code">GNUTLS_EXT_FLAG_APPEND</code> 
</p>
<p><var class="var">critical</var>: the extension status
</p>
<p>This function will get the X.509 TLS features
extension structure from the certificate. The
returned structure needs to be freed using
<code class="code">gnutls_x509_tlsfeatures_deinit()</code> .
</p>
<p>When the  <code class="code">flags</code> is set to <code class="code">GNUTLS_EXT_FLAG_APPEND</code> ,
then if the  <code class="code">features</code> structure is empty this function will behave
identically as if the flag was not set. Otherwise if there are elements 
in the  <code class="code">features</code> structure then they will be merged with.
</p>
<p>Note that  <code class="code">features</code> must be initialized prior to calling this function.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.5.1
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fversion-1"><span>gnutls_x509_crt_get_version<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fversion-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fversion"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fversion"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_version</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fversion"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p>This function will return the version of the specified Certificate.
</p>
<p><strong class="strong">Returns:</strong> version of certificate, or a negative error code on error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fimport-1"><span>gnutls_x509_crt_import<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fimport-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fimport"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fimport"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_import</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, const gnutls_datum_t * <var class="var">data</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fimport"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: The data to store the parsed certificate.
</p>
<p><var class="var">data</var>: The DER or PEM encoded certificate.
</p>
<p><var class="var">format</var>: One of DER or PEM
</p>
<p>This function will convert the given DER or PEM encoded Certificate
to the native gnutls_x509_crt_t format. The output will be stored
in  <code class="code">cert</code> .
</p>
<p>If the Certificate is PEM encoded it should have a header of &quot;X509
CERTIFICATE&quot;, or &quot;CERTIFICATE&quot;.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fimport_005furl-1"><span>gnutls_x509_crt_import_url<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fimport_005furl-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fimport_005furl"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fimport_005furl"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_import_url</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, const char * <var class="var">url</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fimport_005furl"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: A certificate of type <code class="code">gnutls_x509_crt_t</code> 
</p>
<p><var class="var">url</var>: A PKCS 11 url
</p>
<p><var class="var">flags</var>: One of GNUTLS_PKCS11_OBJ_* flags for PKCS<code class="code">11</code>  URLs or zero otherwise
</p>
<p>This function will import a certificate present in a PKCS<code class="code">11</code>  token
or any type of back-end that supports URLs.
</p>
<p>In previous versions of gnutls this function was named
gnutls_x509_crt_import_pkcs11_url, and the old name is
an alias to this one.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005finit-1"><span>gnutls_x509_crt_init<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005finit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005finit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005finit"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_init</strong> <code class="def-code-arguments">(gnutls_x509_crt_t * <var class="var">cert</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005finit"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: A pointer to the type to be initialized
</p>
<p>This function will initialize an X.509 certificate structure.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005flist_005fimport-1"><span>gnutls_x509_crt_list_import<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005flist_005fimport-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005flist_005fimport"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005flist_005fimport"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_list_import</strong> <code class="def-code-arguments">(gnutls_x509_crt_t * <var class="var">certs</var>, unsigned int * <var class="var">cert_max</var>, const gnutls_datum_t * <var class="var">data</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005flist_005fimport"> &para;</a></span></dt>
<dd><p><var class="var">certs</var>: Indicates where the parsed list will be copied to. Must not be initialized.
</p>
<p><var class="var">cert_max</var>: Initially must hold the maximum number of certs. It will be updated with the number of certs available.
</p>
<p><var class="var">data</var>: The PEM encoded certificate.
</p>
<p><var class="var">format</var>: One of DER or PEM.
</p>
<p><var class="var">flags</var>: must be (0) or an OR&rsquo;d sequence of gnutls_certificate_import_flags.
</p>
<p>This function will convert the given PEM encoded certificate list
to the native gnutls_x509_crt_t format. The output will be stored
in  <code class="code">certs</code> .  They will be automatically initialized.
</p>
<p>The flag <code class="code">GNUTLS_X509_CRT_LIST_IMPORT_FAIL_IF_EXCEED</code>  will cause
import to fail if the certificates in the provided buffer are more
than the available structures. The <code class="code">GNUTLS_X509_CRT_LIST_FAIL_IF_UNSORTED</code> 
flag will cause the function to fail if the provided list is not
sorted from subject to issuer.
</p>
<p>If the Certificate is PEM encoded it should have a header of &quot;X509
CERTIFICATE&quot;, or &quot;CERTIFICATE&quot;.
</p>
<p><strong class="strong">Returns:</strong> the number of certificates read or a negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005flist_005fimport2-1"><span>gnutls_x509_crt_list_import2<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005flist_005fimport2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005flist_005fimport2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005flist_005fimport2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_list_import2</strong> <code class="def-code-arguments">(gnutls_x509_crt_t ** <var class="var">certs</var>, unsigned int * <var class="var">size</var>, const gnutls_datum_t * <var class="var">data</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005flist_005fimport2"> &para;</a></span></dt>
<dd><p><var class="var">certs</var>: Will hold the parsed certificate list.
</p>
<p><var class="var">size</var>: It will contain the size of the list.
</p>
<p><var class="var">data</var>: The PEM encoded certificate.
</p>
<p><var class="var">format</var>: One of DER or PEM.
</p>
<p><var class="var">flags</var>: must be (0) or an OR&rsquo;d sequence of gnutls_certificate_import_flags.
</p>
<p>This function will convert the given PEM encoded certificate list
to the native gnutls_x509_crt_t format. The output will be stored
in  <code class="code">certs</code> which will be allocated and initialized.
</p>
<p>If the Certificate is PEM encoded it should have a header of &quot;X509
CERTIFICATE&quot;, or &quot;CERTIFICATE&quot;.
</p>
<p>To deinitialize  <code class="code">certs</code> , you need to deinitialize each crt structure
independently, and use <code class="code">gnutls_free()</code>  at  <code class="code">certs</code> .
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005flist_005fimport_005furl-1"><span>gnutls_x509_crt_list_import_url<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005flist_005fimport_005furl-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005flist_005fimport_005furl"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005flist_005fimport_005furl"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_list_import_url</strong> <code class="def-code-arguments">(gnutls_x509_crt_t ** <var class="var">certs</var>, unsigned int * <var class="var">size</var>, const char * <var class="var">url</var>, gnutls_pin_callback_t <var class="var">pin_fn</var>, void * <var class="var">pin_fn_userdata</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005flist_005fimport_005furl"> &para;</a></span></dt>
<dd><p><var class="var">certs</var>: Will hold the allocated certificate list.
</p>
<p><var class="var">size</var>: It will contain the size of the list.
</p>
<p><var class="var">url</var>: A PKCS 11 url
</p>
<p><var class="var">pin_fn</var>: a PIN callback if not globally set
</p>
<p><var class="var">pin_fn_userdata</var>: parameter for the PIN callback
</p>
<p><var class="var">flags</var>: One of GNUTLS_PKCS11_OBJ_* flags for PKCS<code class="code">11</code>  URLs or zero otherwise
</p>
<p>This function will import a certificate chain present in a PKCS<code class="code">11</code>  token
or any type of back-end that supports URLs. The certificates
must be deinitialized afterwards using <code class="code">gnutls_x509_crt_deinit()</code> 
and the returned pointer must be freed using <code class="code">gnutls_free()</code> .
</p>
<p>The URI provided must be the first certificate in the chain; subsequent
certificates will be retrieved using <code class="code">gnutls_pkcs11_get_raw_issuer()</code>  or
equivalent functionality for the supported URI.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.6.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005flist_005fverify-1"><span>gnutls_x509_crt_list_verify<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005flist_005fverify-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005flist_005fverify"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005flist_005fverify"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_list_verify</strong> <code class="def-code-arguments">(const gnutls_x509_crt_t * <var class="var">cert_list</var>, unsigned <var class="var">cert_list_length</var>, const gnutls_x509_crt_t * <var class="var">CA_list</var>, unsigned <var class="var">CA_list_length</var>, const gnutls_x509_crl_t * <var class="var">CRL_list</var>, unsigned <var class="var">CRL_list_length</var>, unsigned int <var class="var">flags</var>, unsigned int * <var class="var">verify</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005flist_005fverify"> &para;</a></span></dt>
<dd><p><var class="var">cert_list</var>: is the certificate list to be verified
</p>
<p><var class="var">cert_list_length</var>: holds the number of certificate in cert_list
</p>
<p><var class="var">CA_list</var>: is the CA list which will be used in verification
</p>
<p><var class="var">CA_list_length</var>: holds the number of CA certificate in CA_list
</p>
<p><var class="var">CRL_list</var>: holds a list of CRLs.
</p>
<p><var class="var">CRL_list_length</var>: the length of CRL list.
</p>
<p><var class="var">flags</var>: Flags that may be used to change the verification algorithm. Use OR of the gnutls_certificate_verify_flags enumerations.
</p>
<p><var class="var">verify</var>: will hold the certificate verification output.
</p>

<p>This function will try to verify the given certificate list and
return its status. The details of the verification are the same
as in <code class="code">gnutls_x509_trust_list_verify_crt2()</code> .
</p>
<p>You must check the peer&rsquo;s name in order to check if the verified
certificate belongs to the actual peer.
</p>
<p>The certificate verification output will be put in  <code class="code">verify</code> and will
be one or more of the gnutls_certificate_status_t enumerated
elements bitwise or&rsquo;d.  For a more detailed verification status use
<code class="code">gnutls_x509_crt_verify()</code>  per list element.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fprint-1"><span>gnutls_x509_crt_print<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fprint-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fprint"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fprint"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_print</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, gnutls_certificate_print_formats_t <var class="var">format</var>, gnutls_datum_t * <var class="var">out</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fprint"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: The data to be printed
</p>
<p><var class="var">format</var>: Indicate the format to use
</p>
<p><var class="var">out</var>: Newly allocated datum with null terminated string.
</p>
<p>This function will pretty print a X.509 certificate, suitable for
display to a human.
</p>
<p>If the format is <code class="code">GNUTLS_CRT_PRINT_FULL</code>  then all fields of the
certificate will be output, on multiple lines.  The
<code class="code">GNUTLS_CRT_PRINT_ONELINE</code>  format will generate one line with some
selected fields, which is useful for logging purposes.
</p>
<p>The output  <code class="code">out</code> needs to be deallocated using <code class="code">gnutls_free()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fset_005factivation_005ftime-1"><span>gnutls_x509_crt_set_activation_time<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fset_005factivation_005ftime-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fset_005factivation_005ftime"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fset_005factivation_005ftime"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_set_activation_time</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, time_t <var class="var">act_time</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fset_005factivation_005ftime"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: a certificate of type <code class="code">gnutls_x509_crt_t</code> 
</p>
<p><var class="var">act_time</var>: The actual time
</p>
<p>This function will set the time this certificate was or will be
activated.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fset_005fauthority_005finfo_005faccess-1"><span>gnutls_x509_crt_set_authority_info_access<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fset_005fauthority_005finfo_005faccess-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fset_005fauthority_005finfo_005faccess"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fset_005fauthority_005finfo_005faccess"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_set_authority_info_access</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, int <var class="var">what</var>, gnutls_datum_t * <var class="var">data</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fset_005fauthority_005finfo_005faccess"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: Holds the certificate
</p>
<p><var class="var">what</var>: what data to get, a <code class="code">gnutls_info_access_what_t</code>  type.
</p>
<p><var class="var">data</var>: output data to be freed with <code class="code">gnutls_free()</code> .
</p>
<p>This function sets the Authority Information Access (AIA)
extension, see RFC 5280 section 4.2.2.1 for more information.  
</p>
<p>The type of data stored in  <code class="code">data</code> is specified via  <code class="code">what</code> which
should be <code class="code">gnutls_info_access_what_t</code>  values.
</p>
<p>If  <code class="code">what</code> is <code class="code">GNUTLS_IA_OCSP_URI</code> ,  <code class="code">data</code> will hold the OCSP URI.
If  <code class="code">what</code> is <code class="code">GNUTLS_IA_CAISSUERS_URI</code> ,  <code class="code">data</code> will hold the caIssuers
URI.  
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fset_005fauthority_005fkey_005fid-1"><span>gnutls_x509_crt_set_authority_key_id<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fset_005fauthority_005fkey_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fset_005fauthority_005fkey_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fset_005fauthority_005fkey_005fid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_set_authority_key_id</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, const void * <var class="var">id</var>, size_t <var class="var">id_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fset_005fauthority_005fkey_005fid"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: a certificate of type <code class="code">gnutls_x509_crt_t</code> 
</p>
<p><var class="var">id</var>: The key ID
</p>
<p><var class="var">id_size</var>: Holds the size of the key ID field.
</p>
<p>This function will set the X.509 certificate&rsquo;s authority key ID extension.
Only the keyIdentifier field can be set with this function.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fset_005fbasic_005fconstraints-1"><span>gnutls_x509_crt_set_basic_constraints<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fset_005fbasic_005fconstraints-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fset_005fbasic_005fconstraints"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fset_005fbasic_005fconstraints"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_set_basic_constraints</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, unsigned int <var class="var">ca</var>, int <var class="var">pathLenConstraint</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fset_005fbasic_005fconstraints"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: a certificate of type <code class="code">gnutls_x509_crt_t</code> 
</p>
<p><var class="var">ca</var>: true(1) or false(0). Depending on the Certificate authority status.
</p>
<p><var class="var">pathLenConstraint</var>: non-negative error codes indicate maximum length of path,
and negative error codes indicate that the pathLenConstraints field should
not be present.
</p>
<p>This function will set the basicConstraints certificate extension.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fset_005fca_005fstatus-1"><span>gnutls_x509_crt_set_ca_status<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fset_005fca_005fstatus-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fset_005fca_005fstatus"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fset_005fca_005fstatus"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_set_ca_status</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, unsigned int <var class="var">ca</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fset_005fca_005fstatus"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: a certificate of type <code class="code">gnutls_x509_crt_t</code> 
</p>
<p><var class="var">ca</var>: true(1) or false(0). Depending on the Certificate authority status.
</p>
<p>This function will set the basicConstraints certificate extension.
Use <code class="code">gnutls_x509_crt_set_basic_constraints()</code>  if you want to control
the pathLenConstraint field too.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fset_005fcrl_005fdist_005fpoints-1"><span>gnutls_x509_crt_set_crl_dist_points<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fset_005fcrl_005fdist_005fpoints-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fset_005fcrl_005fdist_005fpoints"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fset_005fcrl_005fdist_005fpoints"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_set_crl_dist_points</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, gnutls_x509_subject_alt_name_t <var class="var">type</var>, const void * <var class="var">data_string</var>, unsigned int <var class="var">reason_flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fset_005fcrl_005fdist_005fpoints"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: a certificate of type <code class="code">gnutls_x509_crt_t</code> 
</p>
<p><var class="var">type</var>: is one of the gnutls_x509_subject_alt_name_t enumerations
</p>
<p><var class="var">data_string</var>: The data to be set
</p>
<p><var class="var">reason_flags</var>: revocation reasons
</p>
<p>This function will set the CRL distribution points certificate extension.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fset_005fcrl_005fdist_005fpoints2-1"><span>gnutls_x509_crt_set_crl_dist_points2<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fset_005fcrl_005fdist_005fpoints2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fset_005fcrl_005fdist_005fpoints2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fset_005fcrl_005fdist_005fpoints2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_set_crl_dist_points2</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, gnutls_x509_subject_alt_name_t <var class="var">type</var>, const void * <var class="var">data</var>, unsigned int <var class="var">data_size</var>, unsigned int <var class="var">reason_flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fset_005fcrl_005fdist_005fpoints2"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: a certificate of type <code class="code">gnutls_x509_crt_t</code> 
</p>
<p><var class="var">type</var>: is one of the gnutls_x509_subject_alt_name_t enumerations
</p>
<p><var class="var">data</var>: The data to be set
</p>
<p><var class="var">data_size</var>: The data size
</p>
<p><var class="var">reason_flags</var>: revocation reasons
</p>
<p>This function will set the CRL distribution points certificate extension.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fset_005fcrq-1"><span>gnutls_x509_crt_set_crq<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fset_005fcrq-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fset_005fcrq"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fset_005fcrq"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_set_crq</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, gnutls_x509_crq_t <var class="var">crq</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fset_005fcrq"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: a certificate of type <code class="code">gnutls_x509_crt_t</code> 
</p>
<p><var class="var">crq</var>: holds a certificate request
</p>
<p>This function will set the name and public parameters as well as
the extensions from the given certificate request to the certificate. 
Only RSA keys are currently supported.
</p>
<p>Note that this function will only set the  <code class="code">crq</code> if it is self
signed and the signature is correct. See <code class="code">gnutls_x509_crq_sign2()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fset_005fcrq_005fextension_005fby_005foid-1"><span>gnutls_x509_crt_set_crq_extension_by_oid<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fset_005fcrq_005fextension_005fby_005foid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fset_005fcrq_005fextension_005fby_005foid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fset_005fcrq_005fextension_005fby_005foid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_set_crq_extension_by_oid</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, gnutls_x509_crq_t <var class="var">crq</var>, const char * <var class="var">oid</var>, unsigned <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fset_005fcrq_005fextension_005fby_005foid"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: a certificate of type <code class="code">gnutls_x509_crt_t</code> 
</p>
<p><var class="var">crq</var>: holds a certificate request
</p>
<p><var class="var">oid</var>: the object identifier of the OID to copy
</p>
<p><var class="var">flags</var>: should be zero
</p>
<p>This function will set the extension specify by  <code class="code">oid</code> from the given request to the
certificate.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.5.1
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fset_005fcrq_005fextensions-1"><span>gnutls_x509_crt_set_crq_extensions<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fset_005fcrq_005fextensions-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fset_005fcrq_005fextensions"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fset_005fcrq_005fextensions"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_set_crq_extensions</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, gnutls_x509_crq_t <var class="var">crq</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fset_005fcrq_005fextensions"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: a certificate of type <code class="code">gnutls_x509_crt_t</code> 
</p>
<p><var class="var">crq</var>: holds a certificate request
</p>
<p>This function will set the extensions from the given request to the
certificate.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.8.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fset_005fdn-1"><span>gnutls_x509_crt_set_dn<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fset_005fdn-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fset_005fdn"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fset_005fdn"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_set_dn</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, const char * <var class="var">dn</var>, const char ** <var class="var">err</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fset_005fdn"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: a certificate of type <code class="code">gnutls_x509_crt_t</code> 
</p>
<p><var class="var">dn</var>: a comma separated DN string (RFC4514)
</p>
<p><var class="var">err</var>: indicates the error position (if any)
</p>
<p>This function will set the DN on the provided certificate.
The input string should be plain ASCII or UTF-8 encoded. On
DN parsing error <code class="code">GNUTLS_E_PARSING_ERROR</code>  is returned.
</p>
<p>Note that DNs are not expected to hold DNS information, and thus
no automatic IDNA conversions are attempted when using this function.
If that is required (e.g., store a domain in CN), process the corresponding
input with <code class="code">gnutls_idna_map()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fset_005fdn_005fby_005foid-1"><span>gnutls_x509_crt_set_dn_by_oid<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fset_005fdn_005fby_005foid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fset_005fdn_005fby_005foid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fset_005fdn_005fby_005foid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_set_dn_by_oid</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, const char * <var class="var">oid</var>, unsigned int <var class="var">raw_flag</var>, const void * <var class="var">name</var>, unsigned int <var class="var">sizeof_name</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fset_005fdn_005fby_005foid"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: a certificate of type <code class="code">gnutls_x509_crt_t</code> 
</p>
<p><var class="var">oid</var>: holds an Object Identifier in a null terminated string
</p>
<p><var class="var">raw_flag</var>: must be 0, or 1 if the data are DER encoded
</p>
<p><var class="var">name</var>: a pointer to the name
</p>
<p><var class="var">sizeof_name</var>: holds the size of  <code class="code">name</code> 
</p>
<p>This function will set the part of the name of the Certificate
subject, specified by the given OID. The input string should be
ASCII or UTF-8 encoded.
</p>
<p>Some helper macros with popular OIDs can be found in gnutls/x509.h
With this function you can only set the known OIDs. You can test
for known OIDs using <code class="code">gnutls_x509_dn_oid_known()</code> . For OIDs that are
not known (by gnutls) you should properly DER encode your data,
and call this function with  <code class="code">raw_flag</code> set.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fset_005fexpiration_005ftime-1"><span>gnutls_x509_crt_set_expiration_time<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fset_005fexpiration_005ftime-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fset_005fexpiration_005ftime"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fset_005fexpiration_005ftime"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_set_expiration_time</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, time_t <var class="var">exp_time</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fset_005fexpiration_005ftime"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: a certificate of type <code class="code">gnutls_x509_crt_t</code> 
</p>
<p><var class="var">exp_time</var>: The actual time
</p>
<p>This function will set the time this Certificate will expire.
Setting an expiration time to (time_t)-1 will set
to the no well-defined expiration date value.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fset_005fextension_005fby_005foid-1"><span>gnutls_x509_crt_set_extension_by_oid<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fset_005fextension_005fby_005foid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fset_005fextension_005fby_005foid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fset_005fextension_005fby_005foid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_set_extension_by_oid</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, const char * <var class="var">oid</var>, const void * <var class="var">buf</var>, size_t <var class="var">sizeof_buf</var>, unsigned int <var class="var">critical</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fset_005fextension_005fby_005foid"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: a certificate of type <code class="code">gnutls_x509_crt_t</code> 
</p>
<p><var class="var">oid</var>: holds an Object Identifier in null terminated string
</p>
<p><var class="var">buf</var>: a pointer to a DER encoded data
</p>
<p><var class="var">sizeof_buf</var>: holds the size of  <code class="code">buf</code> 
</p>
<p><var class="var">critical</var>: should be non-zero if the extension is to be marked as critical
</p>
<p>This function will set an the extension, by the specified OID, in
the certificate.  The extension data should be binary data DER
encoded.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fset_005fflags-1"><span>gnutls_x509_crt_set_flags<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fset_005fflags-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fset_005fflags"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fset_005fflags"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_x509_crt_set_flags</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fset_005fflags"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: A type <code class="code">gnutls_x509_crt_t</code> 
</p>
<p><var class="var">flags</var>: flags from the <code class="code">gnutls_x509_crt_flags</code> 
</p>
<p>This function will set flags for the specified certificate.
Currently this is useful for the <code class="code">GNUTLS_X509_CRT_FLAG_IGNORE_SANITY</code> 
which allows importing certificates even if they have known issues.
</p>
<p><strong class="strong">Since:</strong> 3.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fset_005finhibit_005fanypolicy-1"><span>gnutls_x509_crt_set_inhibit_anypolicy<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fset_005finhibit_005fanypolicy-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fset_005finhibit_005fanypolicy"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fset_005finhibit_005fanypolicy"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_set_inhibit_anypolicy</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, unsigned int <var class="var">skipcerts</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fset_005finhibit_005fanypolicy"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: a certificate of type <code class="code">gnutls_x509_crt_t</code> 
</p>
<p><var class="var">skipcerts</var>: number of certificates after which anypolicy is no longer acceptable.
</p>
<p>This function will set the Inhibit anyPolicy certificate extension.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fset_005fissuer_005falt_005fname-1"><span>gnutls_x509_crt_set_issuer_alt_name<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fset_005fissuer_005falt_005fname-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fset_005fissuer_005falt_005fname"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fset_005fissuer_005falt_005fname"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_set_issuer_alt_name</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, gnutls_x509_subject_alt_name_t <var class="var">type</var>, const void * <var class="var">data</var>, unsigned int <var class="var">data_size</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fset_005fissuer_005falt_005fname"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: a certificate of type <code class="code">gnutls_x509_crt_t</code> 
</p>
<p><var class="var">type</var>: is one of the gnutls_x509_subject_alt_name_t enumerations
</p>
<p><var class="var">data</var>: The data to be set
</p>
<p><var class="var">data_size</var>: The size of data to be set
</p>
<p><var class="var">flags</var>: GNUTLS_FSAN_SET to clear previous data or GNUTLS_FSAN_APPEND to append. 
</p>
<p>This function will set the issuer alternative name certificate
extension. It can set the same types as <code class="code">gnutls_x509_crt_set_subject_alt_name()</code> .
</p>
<p>Since version 3.5.7 the <code class="code">GNUTLS_SAN_RFC822NAME</code> , <code class="code">GNUTLS_SAN_DNSNAME</code> , and
<code class="code">GNUTLS_SAN_OTHERNAME_XMPP</code>  are converted to ACE format when necessary.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fset_005fissuer_005falt_005fothername-1"><span>gnutls_x509_crt_set_issuer_alt_othername<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fset_005fissuer_005falt_005fothername-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fset_005fissuer_005falt_005fothername"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fset_005fissuer_005falt_005fothername"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_set_issuer_alt_othername</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, const char * <var class="var">oid</var>, const void * <var class="var">data</var>, unsigned int <var class="var">data_size</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fset_005fissuer_005falt_005fothername"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: a certificate of type <code class="code">gnutls_x509_crt_t</code> 
</p>
<p><var class="var">oid</var>: The other name OID
</p>
<p><var class="var">data</var>: The data to be set
</p>
<p><var class="var">data_size</var>: The size of data to be set
</p>
<p><var class="var">flags</var>: GNUTLS_FSAN_SET to clear previous data or GNUTLS_FSAN_APPEND to append. 
</p>
<p>This function will set an &quot;othername&quot; to the issuer alternative name certificate
extension.
</p>
<p>The values set are set as binary values and are expected to have the proper DER encoding.
For convenience the flags <code class="code">GNUTLS_FSAN_ENCODE_OCTET_STRING</code>  and <code class="code">GNUTLS_FSAN_ENCODE_UTF8_STRING</code> 
can be used to encode the provided data.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.5.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fset_005fissuer_005fdn-1"><span>gnutls_x509_crt_set_issuer_dn<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fset_005fissuer_005fdn-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fset_005fissuer_005fdn"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fset_005fissuer_005fdn"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_set_issuer_dn</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, const char * <var class="var">dn</var>, const char ** <var class="var">err</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fset_005fissuer_005fdn"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: a certificate of type <code class="code">gnutls_x509_crt_t</code> 
</p>
<p><var class="var">dn</var>: a comma separated DN string (RFC4514)
</p>
<p><var class="var">err</var>: indicates the error position (if any)
</p>
<p>This function will set the DN on the provided certificate.
The input string should be plain ASCII or UTF-8 encoded. On
DN parsing error <code class="code">GNUTLS_E_PARSING_ERROR</code>  is returned.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fset_005fissuer_005fdn_005fby_005foid-1"><span>gnutls_x509_crt_set_issuer_dn_by_oid<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fset_005fissuer_005fdn_005fby_005foid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fset_005fissuer_005fdn_005fby_005foid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fset_005fissuer_005fdn_005fby_005foid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_set_issuer_dn_by_oid</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, const char * <var class="var">oid</var>, unsigned int <var class="var">raw_flag</var>, const void * <var class="var">name</var>, unsigned int <var class="var">sizeof_name</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fset_005fissuer_005fdn_005fby_005foid"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: a certificate of type <code class="code">gnutls_x509_crt_t</code> 
</p>
<p><var class="var">oid</var>: holds an Object Identifier in a null terminated string
</p>
<p><var class="var">raw_flag</var>: must be 0, or 1 if the data are DER encoded
</p>
<p><var class="var">name</var>: a pointer to the name
</p>
<p><var class="var">sizeof_name</var>: holds the size of  <code class="code">name</code> 
</p>
<p>This function will set the part of the name of the Certificate
issuer, specified by the given OID.  The input string should be
ASCII or UTF-8 encoded.
</p>
<p>Some helper macros with popular OIDs can be found in gnutls/x509.h
With this function you can only set the known OIDs. You can test
for known OIDs using <code class="code">gnutls_x509_dn_oid_known()</code> . For OIDs that are
not known (by gnutls) you should properly DER encode your data,
and call this function with  <code class="code">raw_flag</code> set.
</p>
<p>Normally you do not need to call this function, since the signing
operation will copy the signer&rsquo;s name as the issuer of the
certificate.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fset_005fissuer_005funique_005fid-1"><span>gnutls_x509_crt_set_issuer_unique_id<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fset_005fissuer_005funique_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fset_005fissuer_005funique_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fset_005fissuer_005funique_005fid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_set_issuer_unique_id</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, const void * <var class="var">id</var>, size_t <var class="var">id_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fset_005fissuer_005funique_005fid"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: a certificate of type <code class="code">gnutls_x509_crt_t</code> 
</p>
<p><var class="var">id</var>: The unique ID
</p>
<p><var class="var">id_size</var>: Holds the size of the unique ID.
</p>
<p>This function will set the X.509 certificate&rsquo;s issuer unique ID field.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.4.7
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fset_005fkey-1"><span>gnutls_x509_crt_set_key<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fset_005fkey-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fset_005fkey"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fset_005fkey"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_set_key</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, gnutls_x509_privkey_t <var class="var">key</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fset_005fkey"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: a certificate of type <code class="code">gnutls_x509_crt_t</code> 
</p>
<p><var class="var">key</var>: holds a private key
</p>
<p>This function will set the public parameters from the given
private key to the certificate.
</p>
<p>To export the public key (i.e., the SubjectPublicKeyInfo part), check
<code class="code">gnutls_pubkey_import_x509()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fset_005fkey_005fpurpose_005foid-1"><span>gnutls_x509_crt_set_key_purpose_oid<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fset_005fkey_005fpurpose_005foid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fset_005fkey_005fpurpose_005foid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fset_005fkey_005fpurpose_005foid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_set_key_purpose_oid</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, const void * <var class="var">oid</var>, unsigned int <var class="var">critical</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fset_005fkey_005fpurpose_005foid"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: a certificate of type <code class="code">gnutls_x509_crt_t</code> 
</p>
<p><var class="var">oid</var>: a pointer to a null terminated string that holds the OID
</p>
<p><var class="var">critical</var>: Whether this extension will be critical or not
</p>
<p>This function will set the key purpose OIDs of the Certificate.
These are stored in the Extended Key Usage extension (2.5.29.37)
See the GNUTLS_KP_* definitions for human readable names.
</p>
<p>Subsequent calls to this function will append OIDs to the OID list.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fset_005fkey_005fusage-1"><span>gnutls_x509_crt_set_key_usage<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fset_005fkey_005fusage-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fset_005fkey_005fusage"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fset_005fkey_005fusage"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_set_key_usage</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, unsigned int <var class="var">usage</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fset_005fkey_005fusage"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: a certificate of type <code class="code">gnutls_x509_crt_t</code> 
</p>
<p><var class="var">usage</var>: an ORed sequence of the GNUTLS_KEY_* elements.
</p>
<p>This function will set the keyUsage certificate extension.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fset_005fname_005fconstraints-1"><span>gnutls_x509_crt_set_name_constraints<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fset_005fname_005fconstraints-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fset_005fname_005fconstraints"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fset_005fname_005fconstraints"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_set_name_constraints</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, gnutls_x509_name_constraints_t <var class="var">nc</var>, unsigned int <var class="var">critical</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fset_005fname_005fconstraints"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: The certificate
</p>
<p><var class="var">nc</var>: The nameconstraints structure
</p>
<p><var class="var">critical</var>: whether this extension will be critical
</p>
<p>This function will set the provided name constraints to
the certificate extension list. This extension is always
marked as critical.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fset_005fpin_005ffunction-1"><span>gnutls_x509_crt_set_pin_function<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fset_005fpin_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fset_005fpin_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fset_005fpin_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_x509_crt_set_pin_function</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, gnutls_pin_callback_t <var class="var">fn</var>, void * <var class="var">userdata</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fset_005fpin_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: The certificate structure
</p>
<p><var class="var">fn</var>: the callback
</p>
<p><var class="var">userdata</var>: data associated with the callback
</p>
<p>This function will set a callback function to be used when
it is required to access a protected object. This function overrides
the global function set using <code class="code">gnutls_pkcs11_set_pin_function()</code> .
</p>
<p>Note that this callback is currently used only during the import
of a PKCS <code class="code">11</code>  certificate with <code class="code">gnutls_x509_crt_import_url()</code> .
</p>
<p><strong class="strong">Since:</strong> 3.1.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fset_005fpolicy-1"><span>gnutls_x509_crt_set_policy<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fset_005fpolicy-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fset_005fpolicy"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fset_005fpolicy"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_set_policy</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, const struct gnutls_x509_policy_st * <var class="var">policy</var>, unsigned int <var class="var">critical</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fset_005fpolicy"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">policy</var>: A pointer to a policy
</p>
<p><var class="var">critical</var>: use non-zero if the extension is marked as critical
</p>
<p>This function will set the certificate policy extension (2.5.29.32).
Multiple calls to this function append a new policy.
</p>
<p>Note the maximum text size for the qualifier <code class="code">GNUTLS_X509_QUALIFIER_NOTICE</code> 
is 200 characters. This function will fail with <code class="code">GNUTLS_E_INVALID_REQUEST</code> 
if this is exceeded.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.1.5
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fset_005fprivate_005fkey_005fusage_005fperiod-1"><span>gnutls_x509_crt_set_private_key_usage_period<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fset_005fprivate_005fkey_005fusage_005fperiod-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fset_005fprivate_005fkey_005fusage_005fperiod"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fset_005fprivate_005fkey_005fusage_005fperiod"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_set_private_key_usage_period</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, time_t <var class="var">activation</var>, time_t <var class="var">expiration</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fset_005fprivate_005fkey_005fusage_005fperiod"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: a certificate of type <code class="code">gnutls_x509_crt_t</code> 
</p>
<p><var class="var">activation</var>: The activation time
</p>
<p><var class="var">expiration</var>: The expiration time
</p>
<p>This function will set the private key usage period extension (2.5.29.16).
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fset_005fproxy-1"><span>gnutls_x509_crt_set_proxy<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fset_005fproxy-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fset_005fproxy"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fset_005fproxy"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_set_proxy</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, int <var class="var">pathLenConstraint</var>, const char * <var class="var">policyLanguage</var>, const char * <var class="var">policy</var>, size_t <var class="var">sizeof_policy</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fset_005fproxy"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: a certificate of type <code class="code">gnutls_x509_crt_t</code> 
</p>
<p><var class="var">pathLenConstraint</var>: non-negative error codes indicate maximum length of path,
and negative error codes indicate that the pathLenConstraints field should
not be present.
</p>
<p><var class="var">policyLanguage</var>: OID describing the language of  <code class="code">policy</code> .
</p>
<p><var class="var">policy</var>: uint8_t byte array with policy language, can be <code class="code">NULL</code> 
</p>
<p><var class="var">sizeof_policy</var>: size of  <code class="code">policy</code> .
</p>
<p>This function will set the proxyCertInfo extension.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fset_005fproxy_005fdn-1"><span>gnutls_x509_crt_set_proxy_dn<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fset_005fproxy_005fdn-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fset_005fproxy_005fdn"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fset_005fproxy_005fdn"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_set_proxy_dn</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, gnutls_x509_crt_t <var class="var">eecrt</var>, unsigned int <var class="var">raw_flag</var>, const void * <var class="var">name</var>, unsigned int <var class="var">sizeof_name</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fset_005fproxy_005fdn"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: a gnutls_x509_crt_t type with the new proxy cert
</p>
<p><var class="var">eecrt</var>: the end entity certificate that will be issuing the proxy
</p>
<p><var class="var">raw_flag</var>: must be 0, or 1 if the CN is DER encoded
</p>
<p><var class="var">name</var>: a pointer to the CN name, may be NULL (but MUST then be added later)
</p>
<p><var class="var">sizeof_name</var>: holds the size of  <code class="code">name</code> 
</p>
<p>This function will set the subject in  <code class="code">crt</code> to the end entity&rsquo;s
 <code class="code">eecrt</code> subject name, and add a single Common Name component  <code class="code">name</code> of size  <code class="code">sizeof_name</code> .  This corresponds to the required proxy
certificate naming style.  Note that if  <code class="code">name</code> is <code class="code">NULL</code> , you MUST
set it later by using <code class="code">gnutls_x509_crt_set_dn_by_oid()</code>  or similar.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fset_005fserial-1"><span>gnutls_x509_crt_set_serial<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fset_005fserial-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fset_005fserial"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fset_005fserial"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_set_serial</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, const void * <var class="var">serial</var>, size_t <var class="var">serial_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fset_005fserial"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: a certificate of type <code class="code">gnutls_x509_crt_t</code> 
</p>
<p><var class="var">serial</var>: The serial number
</p>
<p><var class="var">serial_size</var>: Holds the size of the serial field.
</p>
<p>This function will set the X.509 certificate&rsquo;s serial number.
While the serial number is an integer, it is often handled
as an opaque field by several CAs. For this reason this function
accepts any kind of data as a serial number. To be consistent
with the X.509/PKIX specifications the provided  <code class="code">serial</code> should be 
a big-endian positive number (i.e. its leftmost bit should be zero).
</p>
<p>The size of the serial is restricted to 20 bytes maximum by RFC5280.
This function allows writing more than 20 bytes but the generated
certificates in that case may be rejected by other implementations.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fset_005fspki-1"><span>gnutls_x509_crt_set_spki<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fset_005fspki-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fset_005fspki"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fset_005fspki"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_set_spki</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, const gnutls_x509_spki_t <var class="var">spki</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fset_005fspki"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: a certificate of type <code class="code">gnutls_x509_crt_t</code> 
</p>
<p><var class="var">spki</var>: a SubjectPublicKeyInfo structure of type <code class="code">gnutls_x509_spki_t</code> 
</p>
<p><var class="var">flags</var>: must be zero
</p>
<p>This function will set the certificate&rsquo;s subject public key
information explicitly. This is intended to be used in the cases
where a single public key (e.g., RSA) can be used for multiple
signature algorithms (RSA PKCS1-1.5, and RSA-PSS).
</p>
<p>To export the public key (i.e., the SubjectPublicKeyInfo part), check
<code class="code">gnutls_pubkey_import_x509()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fset_005fsubject_005falt_005fname-1"><span>gnutls_x509_crt_set_subject_alt_name<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fset_005fsubject_005falt_005fname-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fset_005fsubject_005falt_005fname"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fset_005fsubject_005falt_005fname"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_set_subject_alt_name</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, gnutls_x509_subject_alt_name_t <var class="var">type</var>, const void * <var class="var">data</var>, unsigned int <var class="var">data_size</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fset_005fsubject_005falt_005fname"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: a certificate of type <code class="code">gnutls_x509_crt_t</code> 
</p>
<p><var class="var">type</var>: is one of the gnutls_x509_subject_alt_name_t enumerations
</p>
<p><var class="var">data</var>: The data to be set
</p>
<p><var class="var">data_size</var>: The size of data to be set
</p>
<p><var class="var">flags</var>: GNUTLS_FSAN_SET to clear previous data or GNUTLS_FSAN_APPEND to append. 
</p>
<p>This function will set the subject alternative name certificate
extension. It can set the following types: <code class="code">GNUTLS_SAN_DNSNAME</code>  as a text string,
<code class="code">GNUTLS_SAN_RFC822NAME</code>  as a text string, <code class="code">GNUTLS_SAN_URI</code>  as a text string,
<code class="code">GNUTLS_SAN_IPADDRESS</code>  as a binary IP address (4 or 16 bytes),
<code class="code">GNUTLS_SAN_OTHERNAME_XMPP</code>  as a UTF8 string (since 3.5.0).
</p>
<p>Since version 3.5.7 the <code class="code">GNUTLS_SAN_RFC822NAME</code> , <code class="code">GNUTLS_SAN_DNSNAME</code> , and
<code class="code">GNUTLS_SAN_OTHERNAME_XMPP</code>  are converted to ACE format when necessary.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fset_005fsubject_005falt_005fothername-1"><span>gnutls_x509_crt_set_subject_alt_othername<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fset_005fsubject_005falt_005fothername-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fset_005fsubject_005falt_005fothername"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fset_005fsubject_005falt_005fothername"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_set_subject_alt_othername</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, const char * <var class="var">oid</var>, const void * <var class="var">data</var>, unsigned int <var class="var">data_size</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fset_005fsubject_005falt_005fothername"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: a certificate of type <code class="code">gnutls_x509_crt_t</code> 
</p>
<p><var class="var">oid</var>: The other name OID
</p>
<p><var class="var">data</var>: The data to be set
</p>
<p><var class="var">data_size</var>: The size of data to be set
</p>
<p><var class="var">flags</var>: GNUTLS_FSAN_SET to clear previous data or GNUTLS_FSAN_APPEND to append. 
</p>
<p>This function will set an &quot;othername&quot; to the subject alternative name certificate
extension.
</p>
<p>The values set are set as binary values and are expected to have the proper DER encoding.
For convenience the flags <code class="code">GNUTLS_FSAN_ENCODE_OCTET_STRING</code>  and <code class="code">GNUTLS_FSAN_ENCODE_UTF8_STRING</code> 
can be used to encode the provided data.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.5.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fset_005fsubject_005falternative_005fname-1"><span>gnutls_x509_crt_set_subject_alternative_name<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fset_005fsubject_005falternative_005fname-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fset_005fsubject_005falternative_005fname"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fset_005fsubject_005falternative_005fname"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_set_subject_alternative_name</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, gnutls_x509_subject_alt_name_t <var class="var">type</var>, const char * <var class="var">data_string</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fset_005fsubject_005falternative_005fname"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: a certificate of type <code class="code">gnutls_x509_crt_t</code> 
</p>
<p><var class="var">type</var>: is one of the gnutls_x509_subject_alt_name_t enumerations
</p>
<p><var class="var">data_string</var>: The data to be set, a (0) terminated string
</p>
<p>This function will set the subject alternative name certificate
extension. This function assumes that data can be expressed as a null
terminated string.
</p>
<p>The name of the function is unfortunate since it is inconsistent with
<code class="code">gnutls_x509_crt_get_subject_alt_name()</code> .
</p>
<p>See <code class="code">gnutls_x509_crt_set_subject_alt_name()</code>  for more information.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fset_005fsubject_005fkey_005fid-1"><span>gnutls_x509_crt_set_subject_key_id<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fset_005fsubject_005fkey_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fset_005fsubject_005fkey_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fset_005fsubject_005fkey_005fid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_set_subject_key_id</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, const void * <var class="var">id</var>, size_t <var class="var">id_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fset_005fsubject_005fkey_005fid"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: a certificate of type <code class="code">gnutls_x509_crt_t</code> 
</p>
<p><var class="var">id</var>: The key ID
</p>
<p><var class="var">id_size</var>: Holds the size of the subject key ID field.
</p>
<p>This function will set the X.509 certificate&rsquo;s subject key ID
extension.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fset_005fsubject_005funique_005fid-1"><span>gnutls_x509_crt_set_subject_unique_id<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fset_005fsubject_005funique_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fset_005fsubject_005funique_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fset_005fsubject_005funique_005fid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_set_subject_unique_id</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, const void * <var class="var">id</var>, size_t <var class="var">id_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fset_005fsubject_005funique_005fid"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: a certificate of type <code class="code">gnutls_x509_crt_t</code> 
</p>
<p><var class="var">id</var>: The unique ID
</p>
<p><var class="var">id_size</var>: Holds the size of the unique ID.
</p>
<p>This function will set the X.509 certificate&rsquo;s subject unique ID field.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.4.7
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fset_005ftlsfeatures-1"><span>gnutls_x509_crt_set_tlsfeatures<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fset_005ftlsfeatures-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fset_005ftlsfeatures"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fset_005ftlsfeatures"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_set_tlsfeatures</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, gnutls_x509_tlsfeatures_t <var class="var">features</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fset_005ftlsfeatures"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: A X.509 certificate
</p>
<p><var class="var">features</var>: If the function succeeds, the
features will be added to the certificate.
</p>
<p>This function will set the certificates
X.509 TLS extension from the given structure.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.5.1
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fset_005fversion-1"><span>gnutls_x509_crt_set_version<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fset_005fversion-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fset_005fversion"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fset_005fversion"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_set_version</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, unsigned int <var class="var">version</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fset_005fversion"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: a certificate of type <code class="code">gnutls_x509_crt_t</code> 
</p>
<p><var class="var">version</var>: holds the version number. For X.509v1 certificates must be 1.
</p>
<p>This function will set the version of the certificate.  This must
be one for X.509 version 1, and so on.  Plain certificates without
extensions must have version set to one.
</p>
<p>To create well-formed certificates, you must specify version 3 if
you use any certificate extensions.  Extensions are created by
functions such as <code class="code">gnutls_x509_crt_set_subject_alt_name()</code> 
or <code class="code">gnutls_x509_crt_set_key_usage()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fsign-1"><span>gnutls_x509_crt_sign<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fsign-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fsign"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fsign"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_sign</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, gnutls_x509_crt_t <var class="var">issuer</var>, gnutls_x509_privkey_t <var class="var">issuer_key</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fsign"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: a certificate of type <code class="code">gnutls_x509_crt_t</code> 
</p>
<p><var class="var">issuer</var>: is the certificate of the certificate issuer
</p>
<p><var class="var">issuer_key</var>: holds the issuer&rsquo;s private key
</p>
<p>This function is the same a <code class="code">gnutls_x509_crt_sign2()</code>  with no flags,
and an appropriate hash algorithm. The hash algorithm used may
vary between versions of GnuTLS, and it is tied to the security
level of the issuer&rsquo;s public key.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fsign2-1"><span>gnutls_x509_crt_sign2<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fsign2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fsign2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fsign2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_sign2</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, gnutls_x509_crt_t <var class="var">issuer</var>, gnutls_x509_privkey_t <var class="var">issuer_key</var>, gnutls_digest_algorithm_t <var class="var">dig</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fsign2"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: a certificate of type <code class="code">gnutls_x509_crt_t</code> 
</p>
<p><var class="var">issuer</var>: is the certificate of the certificate issuer
</p>
<p><var class="var">issuer_key</var>: holds the issuer&rsquo;s private key
</p>
<p><var class="var">dig</var>: The message digest to use, <code class="code">GNUTLS_DIG_SHA256</code>  is a safe choice
</p>
<p><var class="var">flags</var>: must be 0
</p>
<p>This function will sign the certificate with the issuer&rsquo;s private key, and
will copy the issuer&rsquo;s information into the certificate.
</p>
<p>This must be the last step in a certificate generation since all
the previously set parameters are now signed.
</p>
<p>A known limitation of this function is, that a newly-signed certificate will not
be fully functional (e.g., for signature verification), until it
is exported an re-imported.
</p>
<p>After GnuTLS 3.6.1 the value of  <code class="code">dig</code> may be <code class="code">GNUTLS_DIG_UNKNOWN</code> ,
and in that case, a suitable but reasonable for the key algorithm will be selected.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fverify-1"><span>gnutls_x509_crt_verify<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fverify-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fverify"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fverify"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_verify</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">cert</var>, const gnutls_x509_crt_t * <var class="var">CA_list</var>, unsigned <var class="var">CA_list_length</var>, unsigned int <var class="var">flags</var>, unsigned int * <var class="var">verify</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fverify"> &para;</a></span></dt>
<dd><p><var class="var">cert</var>: is the certificate to be verified
</p>
<p><var class="var">CA_list</var>: is one certificate that is considered to be trusted one
</p>
<p><var class="var">CA_list_length</var>: holds the number of CA certificate in CA_list
</p>
<p><var class="var">flags</var>: Flags that may be used to change the verification algorithm. Use OR of the gnutls_certificate_verify_flags enumerations.
</p>
<p><var class="var">verify</var>: will hold the certificate verification output.
</p>
<p>This function will try to verify the given certificate and return
its status. Note that a verification error does not imply a negative
return status. In that case the  <code class="code">verify</code> status is set.
</p>
<p>The details of the verification are the same
as in <code class="code">gnutls_x509_trust_list_verify_crt2()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fverify_005fdata2-1"><span>gnutls_x509_crt_verify_data2<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fverify_005fdata2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fverify_005fdata2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fverify_005fdata2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_verify_data2</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, gnutls_sign_algorithm_t <var class="var">algo</var>, unsigned int <var class="var">flags</var>, const gnutls_datum_t * <var class="var">data</var>, const gnutls_datum_t * <var class="var">signature</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fverify_005fdata2"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: Holds the certificate to verify with
</p>
<p><var class="var">algo</var>: The signature algorithm used
</p>
<p><var class="var">flags</var>: Zero or an OR list of <code class="code">gnutls_certificate_verify_flags</code> 
</p>
<p><var class="var">data</var>: holds the signed data
</p>
<p><var class="var">signature</var>: contains the signature
</p>
<p>This function will verify the given signed data, using the
parameters from the certificate.
</p>
<p><strong class="strong">Returns:</strong> In case of a verification failure <code class="code">GNUTLS_E_PK_SIG_VERIFY_FAILED</code> 
is returned, <code class="code">GNUTLS_E_EXPIRED</code>  or <code class="code">GNUTLS_E_NOT_YET_ACTIVATED</code>  on expired
or not yet activated certificate and zero or positive code on success.
</p>
<p>Note that since GnuTLS 3.5.6 this function introduces checks in the
end certificate ( <code class="code">crt</code> ), including time checks and key usage checks.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fct_005fsct_005fget-1"><span>gnutls_x509_ct_sct_get<a class="copiable-link" href="#gnutls_005fx509_005fct_005fsct_005fget-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fct_005fsct_005fget"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fct_005fsct_005fget"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_ct_sct_get</strong> <code class="def-code-arguments">(const gnutls_x509_ct_scts_t <var class="var">scts</var>, unsigned <var class="var">idx</var>, time_t * <var class="var">timestamp</var>, gnutls_datum_t * <var class="var">logid</var>, gnutls_sign_algorithm_t * <var class="var">sigalg</var>, gnutls_datum_t * <var class="var">signature</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fct_005fsct_005fget"> &para;</a></span></dt>
<dd><p><var class="var">scts</var>: A list of SCTs
</p>
<p><var class="var">idx</var>: The index of the target SCT in the list
</p>
<p><var class="var">timestamp</var>: The timestamp of the SCT
</p>
<p><var class="var">logid</var>: The LogID field of the SCT; must be freed with <code class="code">gnutls_free()</code> 
</p>
<p><var class="var">sigalg</var>: The signature algorithm
</p>
<p><var class="var">signature</var>: The signature of the SCT; must be freed with <code class="code">gnutls_free()</code> 
</p>
<p>This function will return a specific SCT (Signed Certificate Timestamp)
stored in the SCT list  <code class="code">scts</code> .
</p>
<p>The datums holding the SCT&rsquo;s LogId and signature will be allocated
using <code class="code">gnutls_malloc()</code> .
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  (0) will be returned on success,
<code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  if  <code class="code">idx</code> exceeds the number of SCTs in the list
or a negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fct_005fsct_005fget_005fversion-1"><span>gnutls_x509_ct_sct_get_version<a class="copiable-link" href="#gnutls_005fx509_005fct_005fsct_005fget_005fversion-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fct_005fsct_005fget_005fversion"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fct_005fsct_005fget_005fversion"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_ct_sct_get_version</strong> <code class="def-code-arguments">(gnutls_x509_ct_scts_t <var class="var">scts</var>, unsigned <var class="var">idx</var>, unsigned int * <var class="var">version_out</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fct_005fsct_005fget_005fversion"> &para;</a></span></dt>
<dd><p><var class="var">scts</var>: A list of SCTs
</p>
<p><var class="var">idx</var>: The index of the target SCT in the list
</p>
<p><var class="var">version_out</var>: The version of the target SCT.
</p>
<p>This function obtains the version of the SCT at the given position
in the SCT list.
</p>
<p>The version of that SCT will be placed on  <code class="code">version_out</code> .
</p>
<p>Return : <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned on success,
<code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  if  <code class="code">idx</code> exceeds the number of SCTs in the list
and <code class="code">GNUTLS_E_INVALID_REQUEST</code>  if the SCT&rsquo;s version is different than 1, as that&rsquo;s currently
the only defined version.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fdn_005fdeinit-1"><span>gnutls_x509_dn_deinit<a class="copiable-link" href="#gnutls_005fx509_005fdn_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fdn_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fdn_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_x509_dn_deinit</strong> <code class="def-code-arguments">(gnutls_x509_dn_t <var class="var">dn</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fdn_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">dn</var>: a DN uint8_t object pointer.
</p>
<p>This function deallocates the DN object as returned by
<code class="code">gnutls_x509_dn_import()</code> .
</p>
<p><strong class="strong">Since:</strong> 2.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fdn_005fexport-1"><span>gnutls_x509_dn_export<a class="copiable-link" href="#gnutls_005fx509_005fdn_005fexport-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fdn_005fexport"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fdn_005fexport"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_dn_export</strong> <code class="def-code-arguments">(gnutls_x509_dn_t <var class="var">dn</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, void * <var class="var">output_data</var>, size_t * <var class="var">output_data_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fdn_005fexport"> &para;</a></span></dt>
<dd><p><var class="var">dn</var>: Holds the uint8_t DN object
</p>
<p><var class="var">format</var>: the format of output params. One of PEM or DER.
</p>
<p><var class="var">output_data</var>: will contain a DN PEM or DER encoded
</p>
<p><var class="var">output_data_size</var>: holds the size of output_data (and will be
replaced by the actual size of parameters)
</p>
<p>This function will export the DN to DER or PEM format.
</p>
<p>If the buffer provided is not long enough to hold the output, then
* <code class="code">output_data_size</code> is updated and <code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code> 
will be returned.
</p>
<p>If the structure is PEM encoded, it will have a header
of &quot;BEGIN NAME&quot;.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fdn_005fexport2-1"><span>gnutls_x509_dn_export2<a class="copiable-link" href="#gnutls_005fx509_005fdn_005fexport2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fdn_005fexport2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fdn_005fexport2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_dn_export2</strong> <code class="def-code-arguments">(gnutls_x509_dn_t <var class="var">dn</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, gnutls_datum_t * <var class="var">out</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fdn_005fexport2"> &para;</a></span></dt>
<dd><p><var class="var">dn</var>: Holds the uint8_t DN object
</p>
<p><var class="var">format</var>: the format of output params. One of PEM or DER.
</p>
<p><var class="var">out</var>: will contain a DN PEM or DER encoded
</p>
<p>This function will export the DN to DER or PEM format.
</p>
<p>The output buffer is allocated using <code class="code">gnutls_malloc()</code> .
</p>
<p>If the structure is PEM encoded, it will have a header
of &quot;BEGIN NAME&quot;.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.1.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fdn_005fget_005frdn_005fava-1"><span>gnutls_x509_dn_get_rdn_ava<a class="copiable-link" href="#gnutls_005fx509_005fdn_005fget_005frdn_005fava-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fdn_005fget_005frdn_005fava"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fdn_005fget_005frdn_005fava-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_dn_get_rdn_ava</strong> <code class="def-code-arguments">(gnutls_x509_dn_t <var class="var">dn</var>, int <var class="var">irdn</var>, int <var class="var">iava</var>, gnutls_x509_ava_st * <var class="var">ava</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fdn_005fget_005frdn_005fava-1"> &para;</a></span></dt>
<dd><p><var class="var">dn</var>: a pointer to DN
</p>
<p><var class="var">irdn</var>: index of RDN
</p>
<p><var class="var">iava</var>: index of AVA.
</p>
<p><var class="var">ava</var>: Pointer to structure which will hold output information.
</p>
<p>Get pointers to data within the DN. The format of the  <code class="code">ava</code> structure
is shown below.
</p>
<p>struct gnutls_x509_ava_st {
gnutls_datum_t oid;
gnutls_datum_t value;
unsigned long value_tag;
};
</p>
<p>The X.509 distinguished name is a sequence of sequences of strings
and this is what the  <code class="code">irdn</code> and  <code class="code">iava</code> indexes model.
</p>
<p>Note that  <code class="code">ava</code> will contain pointers into the  <code class="code">dn</code> structure which
in turns points to the original certificate. Thus you should not
modify any data or deallocate any of those.
</p>
<p>This is a low-level function that requires the caller to do the
value conversions when necessary (e.g. from UCS-2).
</p>
<p><strong class="strong">Returns:</strong> Returns 0 on success, or an error code.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fdn_005fget_005fstr-1"><span>gnutls_x509_dn_get_str<a class="copiable-link" href="#gnutls_005fx509_005fdn_005fget_005fstr-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fdn_005fget_005fstr"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fdn_005fget_005fstr"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_dn_get_str</strong> <code class="def-code-arguments">(gnutls_x509_dn_t <var class="var">dn</var>, gnutls_datum_t * <var class="var">str</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fdn_005fget_005fstr"> &para;</a></span></dt>
<dd><p><var class="var">dn</var>: a pointer to DN
</p>
<p><var class="var">str</var>: a datum that will hold the name
</p>
<p>This function will allocate buffer and copy the name in the provided DN.
The name will be in the form &quot;C=xxxx,O=yyyy,CN=zzzz&quot; as
described in RFC4514. The output string will be ASCII or UTF-8
encoded, depending on the certificate data.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.4.2
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fdn_005fget_005fstr2-1"><span>gnutls_x509_dn_get_str2<a class="copiable-link" href="#gnutls_005fx509_005fdn_005fget_005fstr2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fdn_005fget_005fstr2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fdn_005fget_005fstr2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_dn_get_str2</strong> <code class="def-code-arguments">(gnutls_x509_dn_t <var class="var">dn</var>, gnutls_datum_t * <var class="var">str</var>, unsigned <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fdn_005fget_005fstr2"> &para;</a></span></dt>
<dd><p><var class="var">dn</var>: a pointer to DN
</p>
<p><var class="var">str</var>: a datum that will hold the name
</p>
<p><var class="var">flags</var>: zero or <code class="code">GNUTLS_X509_DN_FLAG_COMPAT</code> 
</p>
<p>This function will allocate buffer and copy the name in the provided DN.
The name will be in the form &quot;C=xxxx,O=yyyy,CN=zzzz&quot; as
described in RFC4514. The output string will be ASCII or UTF-8
encoded, depending on the certificate data.
</p>
<p>When the flag <code class="code">GNUTLS_X509_DN_FLAG_COMPAT</code>  is specified, the output
format will match the format output by previous to 3.5.6 versions of GnuTLS
which was not not fully RFC4514-compliant.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.5.7
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fdn_005fimport-1"><span>gnutls_x509_dn_import<a class="copiable-link" href="#gnutls_005fx509_005fdn_005fimport-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fdn_005fimport"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fdn_005fimport"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_dn_import</strong> <code class="def-code-arguments">(gnutls_x509_dn_t <var class="var">dn</var>, const gnutls_datum_t * <var class="var">data</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fdn_005fimport"> &para;</a></span></dt>
<dd><p><var class="var">dn</var>: the structure that will hold the imported DN
</p>
<p><var class="var">data</var>: should contain a DER encoded RDN sequence
</p>
<p>This function parses an RDN sequence and stores the result to a
<code class="code">gnutls_x509_dn_t</code>  type. The data must have been initialized
with <code class="code">gnutls_x509_dn_init()</code> . You may use <code class="code">gnutls_x509_dn_get_rdn_ava()</code>  to
decode the DN.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fdn_005finit-1"><span>gnutls_x509_dn_init<a class="copiable-link" href="#gnutls_005fx509_005fdn_005finit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fdn_005finit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fdn_005finit"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_dn_init</strong> <code class="def-code-arguments">(gnutls_x509_dn_t * <var class="var">dn</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fdn_005finit"> &para;</a></span></dt>
<dd><p><var class="var">dn</var>: the object to be initialized
</p>
<p>This function initializes a <code class="code">gnutls_x509_dn_t</code>  type.
</p>
<p>The object returned must be deallocated using
<code class="code">gnutls_x509_dn_deinit()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fdn_005foid_005fknown-1"><span>gnutls_x509_dn_oid_known<a class="copiable-link" href="#gnutls_005fx509_005fdn_005foid_005fknown-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fdn_005foid_005fknown"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fdn_005foid_005fknown"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_dn_oid_known</strong> <code class="def-code-arguments">(const char * <var class="var">oid</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fdn_005foid_005fknown"> &para;</a></span></dt>
<dd><p><var class="var">oid</var>: holds an Object Identifier in a null terminated string
</p>
<p>This function will inform about known DN OIDs. This is useful since
functions like <code class="code">gnutls_x509_crt_set_dn_by_oid()</code>  use the information
on known OIDs to properly encode their input. Object Identifiers
that are not known are not encoded by these functions, and their
input is stored directly into the ASN.1 structure. In that case of
unknown OIDs, you have the responsibility of DER encoding your
data.
</p>
<p><strong class="strong">Returns:</strong> 1 on known OIDs and 0 otherwise.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fdn_005foid_005fname-1"><span>gnutls_x509_dn_oid_name<a class="copiable-link" href="#gnutls_005fx509_005fdn_005foid_005fname-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fdn_005foid_005fname"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fdn_005foid_005fname"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_x509_dn_oid_name</strong> <code class="def-code-arguments">(const char * <var class="var">oid</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fdn_005foid_005fname"> &para;</a></span></dt>
<dd><p><var class="var">oid</var>: holds an Object Identifier in a null terminated string
</p>
<p><var class="var">flags</var>: 0 or GNUTLS_X509_DN_OID_*
</p>
<p>This function will return the name of a known DN OID. If
<code class="code">GNUTLS_X509_DN_OID_RETURN_OID</code>  is specified this function
will return the given OID if no descriptive name has been
found.
</p>
<p><strong class="strong">Returns:</strong> A null terminated string or NULL otherwise.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fdn_005fset_005fstr-1"><span>gnutls_x509_dn_set_str<a class="copiable-link" href="#gnutls_005fx509_005fdn_005fset_005fstr-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fdn_005fset_005fstr"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fdn_005fset_005fstr"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_dn_set_str</strong> <code class="def-code-arguments">(gnutls_x509_dn_t <var class="var">dn</var>, const char * <var class="var">str</var>, const char ** <var class="var">err</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fdn_005fset_005fstr"> &para;</a></span></dt>
<dd><p><var class="var">dn</var>: a pointer to DN
</p>
<p><var class="var">str</var>: a comma separated DN string (RFC4514)
</p>
<p><var class="var">err</var>: indicates the error position (if any)
</p>
<p>This function will set the DN on the provided DN structure.
The input string should be plain ASCII or UTF-8 encoded. On
DN parsing error <code class="code">GNUTLS_E_PARSING_ERROR</code>  is returned.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.5.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fext_005fct_005fexport_005fscts-1"><span>gnutls_x509_ext_ct_export_scts<a class="copiable-link" href="#gnutls_005fx509_005fext_005fct_005fexport_005fscts-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fext_005fct_005fexport_005fscts"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fext_005fct_005fexport_005fscts"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_ext_ct_export_scts</strong> <code class="def-code-arguments">(const gnutls_x509_ct_scts_t <var class="var">scts</var>, gnutls_datum_t * <var class="var">ext</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fext_005fct_005fexport_005fscts"> &para;</a></span></dt>
<dd><p><var class="var">scts</var>: An initialized SCT list
</p>
<p><var class="var">ext</var>: The DER-encoded extension data; must be freed with <code class="code">gnutls_free()</code> 
</p>
<p>This function will convert the provided list of SCTs to a DER-encoded
SignedCertificateTimestampList extension (1.3.6.1.4.1.11129.2.4.2).
The output data in  <code class="code">ext</code> will be allocated using <code class="code">gnutls_malloc()</code> .
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  (0) on success or a negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fext_005fct_005fimport_005fscts-1"><span>gnutls_x509_ext_ct_import_scts<a class="copiable-link" href="#gnutls_005fx509_005fext_005fct_005fimport_005fscts-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fext_005fct_005fimport_005fscts"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fext_005fct_005fimport_005fscts"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_ext_ct_import_scts</strong> <code class="def-code-arguments">(const gnutls_datum_t * <var class="var">ext</var>, gnutls_x509_ct_scts_t <var class="var">scts</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fext_005fct_005fimport_005fscts"> &para;</a></span></dt>
<dd><p><var class="var">ext</var>: a DER-encoded extension
</p>
<p><var class="var">scts</var>: The SCT list
</p>
<p><var class="var">flags</var>: should be zero
</p>
<p>This function will read a SignedCertificateTimestampList structure
from the DER data of the X.509 Certificate Transparency SCT extension
(OID 1.3.6.1.4.1.11129.2.4.2).
</p>
<p>The list of SCTs (Signed Certificate Timestamps) is placed on  <code class="code">scts</code> ,
which must be previously initialized with <code class="code">gnutls_x509_ext_ct_scts_init()</code> .
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  (0) on success or a negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fext_005fct_005fscts_005fdeinit-1"><span>gnutls_x509_ext_ct_scts_deinit<a class="copiable-link" href="#gnutls_005fx509_005fext_005fct_005fscts_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fext_005fct_005fscts_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fext_005fct_005fscts_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_x509_ext_ct_scts_deinit</strong> <code class="def-code-arguments">(gnutls_x509_ct_scts_t <var class="var">scts</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fext_005fct_005fscts_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">scts</var>: The SCT list
</p>
<p>This function will deinitialize a Certificate Transparency SCT list.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fext_005fct_005fscts_005finit-1"><span>gnutls_x509_ext_ct_scts_init<a class="copiable-link" href="#gnutls_005fx509_005fext_005fct_005fscts_005finit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fext_005fct_005fscts_005finit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fext_005fct_005fscts_005finit"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_ext_ct_scts_init</strong> <code class="def-code-arguments">(gnutls_x509_ct_scts_t * <var class="var">scts</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fext_005fct_005fscts_005finit"> &para;</a></span></dt>
<dd><p><var class="var">scts</var>: The SCT list
</p>
<p>This function will initialize a Certificate Transparency SCT list.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  (0) on success, otherwise a negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fext_005fdeinit-1"><span>gnutls_x509_ext_deinit<a class="copiable-link" href="#gnutls_005fx509_005fext_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fext_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fext_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_x509_ext_deinit</strong> <code class="def-code-arguments">(gnutls_x509_ext_st * <var class="var">ext</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fext_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">ext</var>: The extensions structure
</p>
<p>This function will deinitialize an extensions structure.
</p>
<p><strong class="strong">Since:</strong> 3.3.8
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fext_005fexport_005faia-1"><span>gnutls_x509_ext_export_aia<a class="copiable-link" href="#gnutls_005fx509_005fext_005fexport_005faia-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fext_005fexport_005faia"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fext_005fexport_005faia"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_ext_export_aia</strong> <code class="def-code-arguments">(gnutls_x509_aia_t <var class="var">aia</var>, gnutls_datum_t * <var class="var">ext</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fext_005fexport_005faia"> &para;</a></span></dt>
<dd><p><var class="var">aia</var>: The authority info access
</p>
<p><var class="var">ext</var>: The DER-encoded extension data; must be freed using <code class="code">gnutls_free()</code> .
</p>
<p>This function will DER encode the Authority Information Access (AIA)
extension; see RFC 5280 section 4.2.2.1 for more information on the
extension.  
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fext_005fexport_005fauthority_005fkey_005fid-1"><span>gnutls_x509_ext_export_authority_key_id<a class="copiable-link" href="#gnutls_005fx509_005fext_005fexport_005fauthority_005fkey_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fext_005fexport_005fauthority_005fkey_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fext_005fexport_005fauthority_005fkey_005fid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_ext_export_authority_key_id</strong> <code class="def-code-arguments">(gnutls_x509_aki_t <var class="var">aki</var>, gnutls_datum_t * <var class="var">ext</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fext_005fexport_005fauthority_005fkey_005fid"> &para;</a></span></dt>
<dd><p><var class="var">aki</var>: An initialized authority key identifier
</p>
<p><var class="var">ext</var>: The DER-encoded extension data; must be freed using <code class="code">gnutls_free()</code> .
</p>
<p>This function will convert the provided key identifier to a
DER-encoded PKIX AuthorityKeyIdentifier extension. 
The output data in  <code class="code">ext</code> will be allocated using
<code class="code">gnutls_malloc()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fext_005fexport_005fbasic_005fconstraints-1"><span>gnutls_x509_ext_export_basic_constraints<a class="copiable-link" href="#gnutls_005fx509_005fext_005fexport_005fbasic_005fconstraints-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fext_005fexport_005fbasic_005fconstraints"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fext_005fexport_005fbasic_005fconstraints"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_ext_export_basic_constraints</strong> <code class="def-code-arguments">(unsigned int <var class="var">ca</var>, int <var class="var">pathlen</var>, gnutls_datum_t * <var class="var">ext</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fext_005fexport_005fbasic_005fconstraints"> &para;</a></span></dt>
<dd><p><var class="var">ca</var>: non-zero for a CA
</p>
<p><var class="var">pathlen</var>: The path length constraint (set to -1 for no constraint)
</p>
<p><var class="var">ext</var>: The DER-encoded extension data; must be freed using <code class="code">gnutls_free()</code> .
</p>
<p>This function will convert the parameters provided to a basic constraints
DER encoded extension (2.5.29.19).
The  <code class="code">ext</code> data will be allocated using
<code class="code">gnutls_malloc()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fext_005fexport_005fcrl_005fdist_005fpoints-1"><span>gnutls_x509_ext_export_crl_dist_points<a class="copiable-link" href="#gnutls_005fx509_005fext_005fexport_005fcrl_005fdist_005fpoints-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fext_005fexport_005fcrl_005fdist_005fpoints"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fext_005fexport_005fcrl_005fdist_005fpoints"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_ext_export_crl_dist_points</strong> <code class="def-code-arguments">(gnutls_x509_crl_dist_points_t <var class="var">cdp</var>, gnutls_datum_t * <var class="var">ext</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fext_005fexport_005fcrl_005fdist_005fpoints"> &para;</a></span></dt>
<dd><p><var class="var">cdp</var>: A pointer to an initialized CRL distribution points.
</p>
<p><var class="var">ext</var>: The DER-encoded extension data; must be freed using <code class="code">gnutls_free()</code> .
</p>
<p>This function will convert the provided policies, to a certificate policy
DER encoded extension (2.5.29.31).
</p>
<p>The  <code class="code">ext</code> data will be allocated using <code class="code">gnutls_malloc()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fext_005fexport_005finhibit_005fanypolicy-1"><span>gnutls_x509_ext_export_inhibit_anypolicy<a class="copiable-link" href="#gnutls_005fx509_005fext_005fexport_005finhibit_005fanypolicy-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fext_005fexport_005finhibit_005fanypolicy"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fext_005fexport_005finhibit_005fanypolicy"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_ext_export_inhibit_anypolicy</strong> <code class="def-code-arguments">(unsigned int <var class="var">skipcerts</var>, gnutls_datum_t * <var class="var">ext</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fext_005fexport_005finhibit_005fanypolicy"> &para;</a></span></dt>
<dd><p><var class="var">skipcerts</var>: number of certificates after which anypolicy is no longer acceptable.
</p>
<p><var class="var">ext</var>: The DER-encoded extension data; must be freed using <code class="code">gnutls_free()</code> .
</p>
<p>This function will convert the  <code class="code">skipcerts</code> value to a DER
encoded Inhibit AnyPolicy PKIX extension. The  <code class="code">ext</code> data will be allocated using
<code class="code">gnutls_malloc()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fext_005fexport_005fkey_005fpurposes-1"><span>gnutls_x509_ext_export_key_purposes<a class="copiable-link" href="#gnutls_005fx509_005fext_005fexport_005fkey_005fpurposes-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fext_005fexport_005fkey_005fpurposes"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fext_005fexport_005fkey_005fpurposes"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_ext_export_key_purposes</strong> <code class="def-code-arguments">(gnutls_x509_key_purposes_t <var class="var">p</var>, gnutls_datum_t * <var class="var">ext</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fext_005fexport_005fkey_005fpurposes"> &para;</a></span></dt>
<dd><p><var class="var">p</var>: The key purposes
</p>
<p><var class="var">ext</var>: The DER-encoded extension data; must be freed using <code class="code">gnutls_free()</code> .
</p>
<p>This function will convert the key purposes type to a
DER-encoded PKIX ExtKeyUsageSyntax (2.5.29.37) extension. The output data in 
 <code class="code">ext</code> will be allocated using <code class="code">gnutls_malloc()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fext_005fexport_005fkey_005fusage-1"><span>gnutls_x509_ext_export_key_usage<a class="copiable-link" href="#gnutls_005fx509_005fext_005fexport_005fkey_005fusage-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fext_005fexport_005fkey_005fusage"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fext_005fexport_005fkey_005fusage"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_ext_export_key_usage</strong> <code class="def-code-arguments">(unsigned int <var class="var">usage</var>, gnutls_datum_t * <var class="var">ext</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fext_005fexport_005fkey_005fusage"> &para;</a></span></dt>
<dd><p><var class="var">usage</var>: an ORed sequence of the GNUTLS_KEY_* elements.
</p>
<p><var class="var">ext</var>: The DER-encoded extension data; must be freed using <code class="code">gnutls_free()</code> .
</p>
<p>This function will convert the keyUsage bit string to a DER
encoded PKIX extension. The  <code class="code">ext</code> data will be allocated using
<code class="code">gnutls_malloc()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fext_005fexport_005fname_005fconstraints-1"><span>gnutls_x509_ext_export_name_constraints<a class="copiable-link" href="#gnutls_005fx509_005fext_005fexport_005fname_005fconstraints-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fext_005fexport_005fname_005fconstraints"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fext_005fexport_005fname_005fconstraints"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_ext_export_name_constraints</strong> <code class="def-code-arguments">(gnutls_x509_name_constraints_t <var class="var">nc</var>, gnutls_datum_t * <var class="var">ext</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fext_005fexport_005fname_005fconstraints"> &para;</a></span></dt>
<dd><p><var class="var">nc</var>: The nameconstraints
</p>
<p><var class="var">ext</var>: The DER-encoded extension data; must be freed using <code class="code">gnutls_free()</code> .
</p>
<p>This function will convert the provided name constraints type to a
DER-encoded PKIX NameConstraints (2.5.29.30) extension. The output data in 
 <code class="code">ext</code> will be allocated using <code class="code">gnutls_malloc()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fext_005fexport_005fpolicies-1"><span>gnutls_x509_ext_export_policies<a class="copiable-link" href="#gnutls_005fx509_005fext_005fexport_005fpolicies-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fext_005fexport_005fpolicies"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fext_005fexport_005fpolicies"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_ext_export_policies</strong> <code class="def-code-arguments">(gnutls_x509_policies_t <var class="var">policies</var>, gnutls_datum_t * <var class="var">ext</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fext_005fexport_005fpolicies"> &para;</a></span></dt>
<dd><p><var class="var">policies</var>: A pointer to an initialized policies.
</p>
<p><var class="var">ext</var>: The DER-encoded extension data; must be freed using <code class="code">gnutls_free()</code> .
</p>
<p>This function will convert the provided policies, to a certificate policy
DER encoded extension (2.5.29.32).
</p>
<p>The  <code class="code">ext</code> data will be allocated using <code class="code">gnutls_malloc()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fext_005fexport_005fprivate_005fkey_005fusage_005fperiod-1"><span>gnutls_x509_ext_export_private_key_usage_period<a class="copiable-link" href="#gnutls_005fx509_005fext_005fexport_005fprivate_005fkey_005fusage_005fperiod-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fext_005fexport_005fprivate_005fkey_005fusage_005fperiod"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fext_005fexport_005fprivate_005fkey_005fusage_005fperiod"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_ext_export_private_key_usage_period</strong> <code class="def-code-arguments">(time_t <var class="var">activation</var>, time_t <var class="var">expiration</var>, gnutls_datum_t * <var class="var">ext</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fext_005fexport_005fprivate_005fkey_005fusage_005fperiod"> &para;</a></span></dt>
<dd><p><var class="var">activation</var>: The activation time
</p>
<p><var class="var">expiration</var>: The expiration time
</p>
<p><var class="var">ext</var>: The DER-encoded extension data; must be freed using <code class="code">gnutls_free()</code> .
</p>
<p>This function will convert the periods provided to a private key
usage DER encoded extension (2.5.29.16).
The  <code class="code">ext</code> data will be allocated using
<code class="code">gnutls_malloc()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fext_005fexport_005fproxy-1"><span>gnutls_x509_ext_export_proxy<a class="copiable-link" href="#gnutls_005fx509_005fext_005fexport_005fproxy-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fext_005fexport_005fproxy"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fext_005fexport_005fproxy"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_ext_export_proxy</strong> <code class="def-code-arguments">(int <var class="var">pathLenConstraint</var>, const char * <var class="var">policyLanguage</var>, const char * <var class="var">policy</var>, size_t <var class="var">sizeof_policy</var>, gnutls_datum_t * <var class="var">ext</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fext_005fexport_005fproxy"> &para;</a></span></dt>
<dd><p><var class="var">pathLenConstraint</var>: A negative value will remove the path length constraint,
while non-negative values will be set as the length of the pathLenConstraints field.
</p>
<p><var class="var">policyLanguage</var>: OID describing the language of  <code class="code">policy</code> .
</p>
<p><var class="var">policy</var>: uint8_t byte array with policy language, can be <code class="code">NULL</code> 
</p>
<p><var class="var">sizeof_policy</var>: size of  <code class="code">policy</code> .
</p>
<p><var class="var">ext</var>: The DER-encoded extension data; must be freed using <code class="code">gnutls_free()</code> .
</p>
<p>This function will convert the parameters provided to a proxyCertInfo extension.
</p>
<p>The  <code class="code">ext</code> data will be allocated using <code class="code">gnutls_malloc()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fext_005fexport_005fsubject_005falt_005fnames-1"><span>gnutls_x509_ext_export_subject_alt_names<a class="copiable-link" href="#gnutls_005fx509_005fext_005fexport_005fsubject_005falt_005fnames-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fext_005fexport_005fsubject_005falt_005fnames"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fext_005fexport_005fsubject_005falt_005fnames"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_ext_export_subject_alt_names</strong> <code class="def-code-arguments">(gnutls_subject_alt_names_t <var class="var">sans</var>, gnutls_datum_t * <var class="var">ext</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fext_005fexport_005fsubject_005falt_005fnames"> &para;</a></span></dt>
<dd><p><var class="var">sans</var>: The alternative names
</p>
<p><var class="var">ext</var>: The DER-encoded extension data; must be freed using <code class="code">gnutls_free()</code> .
</p>
<p>This function will convert the provided alternative names structure to a
DER-encoded SubjectAltName PKIX extension. The output data in  <code class="code">ext</code> will be allocated using
<code class="code">gnutls_malloc()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fext_005fexport_005fsubject_005fkey_005fid-1"><span>gnutls_x509_ext_export_subject_key_id<a class="copiable-link" href="#gnutls_005fx509_005fext_005fexport_005fsubject_005fkey_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fext_005fexport_005fsubject_005fkey_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fext_005fexport_005fsubject_005fkey_005fid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_ext_export_subject_key_id</strong> <code class="def-code-arguments">(const gnutls_datum_t * <var class="var">id</var>, gnutls_datum_t * <var class="var">ext</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fext_005fexport_005fsubject_005fkey_005fid"> &para;</a></span></dt>
<dd><p><var class="var">id</var>: The key identifier
</p>
<p><var class="var">ext</var>: The DER-encoded extension data; must be freed using <code class="code">gnutls_free()</code> .
</p>
<p>This function will convert the provided key identifier to a
DER-encoded PKIX SubjectKeyIdentifier extension. 
The output data in  <code class="code">ext</code> will be allocated using
<code class="code">gnutls_malloc()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fext_005fexport_005ftlsfeatures-1"><span>gnutls_x509_ext_export_tlsfeatures<a class="copiable-link" href="#gnutls_005fx509_005fext_005fexport_005ftlsfeatures-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fext_005fexport_005ftlsfeatures"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fext_005fexport_005ftlsfeatures"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_ext_export_tlsfeatures</strong> <code class="def-code-arguments">(gnutls_x509_tlsfeatures_t <var class="var">f</var>, gnutls_datum_t * <var class="var">ext</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fext_005fexport_005ftlsfeatures"> &para;</a></span></dt>
<dd><p><var class="var">f</var>: The features structure
</p>
<p><var class="var">ext</var>: The DER-encoded extension data; must be freed using <code class="code">gnutls_free()</code> .
</p>
<p>This function will convert the provided TLS features structure structure to a
DER-encoded TLS features PKIX extension. The output data in  <code class="code">ext</code> will be allocated using
<code class="code">gnutls_malloc()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.5.1
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fext_005fimport_005faia-1"><span>gnutls_x509_ext_import_aia<a class="copiable-link" href="#gnutls_005fx509_005fext_005fimport_005faia-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fext_005fimport_005faia"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fext_005fimport_005faia"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_ext_import_aia</strong> <code class="def-code-arguments">(const gnutls_datum_t * <var class="var">ext</var>, gnutls_x509_aia_t <var class="var">aia</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fext_005fimport_005faia"> &para;</a></span></dt>
<dd><p><var class="var">ext</var>: The DER-encoded extension data
</p>
<p><var class="var">aia</var>: The authority info access
</p>
<p><var class="var">flags</var>: should be zero
</p>
<p>This function extracts the Authority Information Access (AIA)
extension from the provided DER-encoded data; see RFC 5280 section 4.2.2.1 
for more information on the extension.  The
AIA extension holds a sequence of AccessDescription (AD) data.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fext_005fimport_005fauthority_005fkey_005fid-1"><span>gnutls_x509_ext_import_authority_key_id<a class="copiable-link" href="#gnutls_005fx509_005fext_005fimport_005fauthority_005fkey_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fext_005fimport_005fauthority_005fkey_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fext_005fimport_005fauthority_005fkey_005fid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_ext_import_authority_key_id</strong> <code class="def-code-arguments">(const gnutls_datum_t * <var class="var">ext</var>, gnutls_x509_aki_t <var class="var">aki</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fext_005fimport_005fauthority_005fkey_005fid"> &para;</a></span></dt>
<dd><p><var class="var">ext</var>: a DER encoded extension
</p>
<p><var class="var">aki</var>: An initialized authority key identifier type
</p>
<p><var class="var">flags</var>: should be zero
</p>
<p>This function will return the subject key ID stored in the provided
AuthorityKeyIdentifier extension.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> 
if the extension is not present, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fext_005fimport_005fbasic_005fconstraints-1"><span>gnutls_x509_ext_import_basic_constraints<a class="copiable-link" href="#gnutls_005fx509_005fext_005fimport_005fbasic_005fconstraints-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fext_005fimport_005fbasic_005fconstraints"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fext_005fimport_005fbasic_005fconstraints"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_ext_import_basic_constraints</strong> <code class="def-code-arguments">(const gnutls_datum_t * <var class="var">ext</var>, unsigned int * <var class="var">ca</var>, int * <var class="var">pathlen</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fext_005fimport_005fbasic_005fconstraints"> &para;</a></span></dt>
<dd><p><var class="var">ext</var>: the DER encoded extension data
</p>
<p><var class="var">ca</var>: will be non zero if the CA status is true
</p>
<p><var class="var">pathlen</var>: the path length constraint; will be set to -1 for no limit
</p>
<p>This function will return the CA status and path length constraint
as written in the PKIX extension 2.5.29.19.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fext_005fimport_005fcrl_005fdist_005fpoints-1"><span>gnutls_x509_ext_import_crl_dist_points<a class="copiable-link" href="#gnutls_005fx509_005fext_005fimport_005fcrl_005fdist_005fpoints-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fext_005fimport_005fcrl_005fdist_005fpoints"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fext_005fimport_005fcrl_005fdist_005fpoints"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_ext_import_crl_dist_points</strong> <code class="def-code-arguments">(const gnutls_datum_t * <var class="var">ext</var>, gnutls_x509_crl_dist_points_t <var class="var">cdp</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fext_005fimport_005fcrl_005fdist_005fpoints"> &para;</a></span></dt>
<dd><p><var class="var">ext</var>: the DER encoded extension data
</p>
<p><var class="var">cdp</var>: A pointer to an initialized CRL distribution points.
</p>
<p><var class="var">flags</var>: should be zero
</p>
<p>This function will extract the CRL distribution points extension (2.5.29.31) 
and store it into the provided type.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fext_005fimport_005finhibit_005fanypolicy-1"><span>gnutls_x509_ext_import_inhibit_anypolicy<a class="copiable-link" href="#gnutls_005fx509_005fext_005fimport_005finhibit_005fanypolicy-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fext_005fimport_005finhibit_005fanypolicy"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fext_005fimport_005finhibit_005fanypolicy"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_ext_import_inhibit_anypolicy</strong> <code class="def-code-arguments">(const gnutls_datum_t * <var class="var">ext</var>, unsigned int * <var class="var">skipcerts</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fext_005fimport_005finhibit_005fanypolicy"> &para;</a></span></dt>
<dd><p><var class="var">ext</var>: the DER encoded extension data
</p>
<p><var class="var">skipcerts</var>: will hold the number of certificates after which anypolicy is no longer acceptable.
</p>
<p>This function will return certificate&rsquo;s value of SkipCerts,
by reading the DER data of the Inhibit anyPolicy X.509 extension (2.5.29.54).
</p>
<p>The  <code class="code">skipcerts</code> value is the number of additional certificates that
may appear in the path before the anyPolicy (<code class="code">GNUTLS_X509_OID_POLICY_ANY</code> )
is no longer acceptable.
</p>
<p><strong class="strong">Returns:</strong> zero, or a negative error code in case of
parsing error.  If the certificate does not contain the Inhibit anyPolicy
extension <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  will be
returned.
</p>
<p><strong class="strong">Since:</strong> 3.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fext_005fimport_005fkey_005fpurposes-1"><span>gnutls_x509_ext_import_key_purposes<a class="copiable-link" href="#gnutls_005fx509_005fext_005fimport_005fkey_005fpurposes-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fext_005fimport_005fkey_005fpurposes"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fext_005fimport_005fkey_005fpurposes"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_ext_import_key_purposes</strong> <code class="def-code-arguments">(const gnutls_datum_t * <var class="var">ext</var>, gnutls_x509_key_purposes_t <var class="var">p</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fext_005fimport_005fkey_005fpurposes"> &para;</a></span></dt>
<dd><p><var class="var">ext</var>: The DER-encoded extension data
</p>
<p><var class="var">p</var>: The key purposes
</p>
<p><var class="var">flags</var>: should be zero
</p>
<p>This function will extract the key purposes in the provided DER-encoded
ExtKeyUsageSyntax PKIX extension, to a <code class="code">gnutls_x509_key_purposes_t</code>  type. 
The data must be initialized.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fext_005fimport_005fkey_005fusage-1"><span>gnutls_x509_ext_import_key_usage<a class="copiable-link" href="#gnutls_005fx509_005fext_005fimport_005fkey_005fusage-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fext_005fimport_005fkey_005fusage"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fext_005fimport_005fkey_005fusage"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_ext_import_key_usage</strong> <code class="def-code-arguments">(const gnutls_datum_t * <var class="var">ext</var>, unsigned int * <var class="var">key_usage</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fext_005fimport_005fkey_005fusage"> &para;</a></span></dt>
<dd><p><var class="var">ext</var>: the DER encoded extension data
</p>
<p><var class="var">key_usage</var>: where the key usage bits will be stored
</p>
<p>This function will return certificate&rsquo;s key usage, by reading the DER
data of the keyUsage X.509 extension (2.5.29.15). The key usage value will ORed
values of the: <code class="code">GNUTLS_KEY_DIGITAL_SIGNATURE</code> ,
<code class="code">GNUTLS_KEY_NON_REPUDIATION</code> , <code class="code">GNUTLS_KEY_KEY_ENCIPHERMENT</code> ,
<code class="code">GNUTLS_KEY_DATA_ENCIPHERMENT</code> , <code class="code">GNUTLS_KEY_KEY_AGREEMENT</code> ,
<code class="code">GNUTLS_KEY_KEY_CERT_SIGN</code> , <code class="code">GNUTLS_KEY_CRL_SIGN</code> ,
<code class="code">GNUTLS_KEY_ENCIPHER_ONLY</code> , <code class="code">GNUTLS_KEY_DECIPHER_ONLY</code> .
</p>
<p><strong class="strong">Returns:</strong> the certificate key usage, or a negative error code in case of
parsing error.  If the certificate does not contain the keyUsage
extension <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  will be
returned.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fext_005fimport_005fname_005fconstraints-1"><span>gnutls_x509_ext_import_name_constraints<a class="copiable-link" href="#gnutls_005fx509_005fext_005fimport_005fname_005fconstraints-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fext_005fimport_005fname_005fconstraints"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fext_005fimport_005fname_005fconstraints"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_ext_import_name_constraints</strong> <code class="def-code-arguments">(const gnutls_datum_t * <var class="var">ext</var>, gnutls_x509_name_constraints_t <var class="var">nc</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fext_005fimport_005fname_005fconstraints"> &para;</a></span></dt>
<dd><p><var class="var">ext</var>: a DER encoded extension
</p>
<p><var class="var">nc</var>: The nameconstraints
</p>
<p><var class="var">flags</var>: zero or <code class="code">GNUTLS_NAME_CONSTRAINTS_FLAG_APPEND</code> 
</p>
<p>This function will return an intermediate type containing
the name constraints of the provided NameConstraints extension. That
can be used in combination with <code class="code">gnutls_x509_name_constraints_check()</code> 
to verify whether a server&rsquo;s name is in accordance with the constraints.
</p>
<p>When the  <code class="code">flags</code> is set to <code class="code">GNUTLS_NAME_CONSTRAINTS_FLAG_APPEND</code> , then if 
the  <code class="code">nc</code> type is empty this function will behave identically as if the flag was not set.
Otherwise if there are elements in the  <code class="code">nc</code> structure then the
constraints will be merged with the existing constraints following
RFC5280 p6.1.4 (excluded constraints will be appended, permitted
will be intersected).
</p>
<p>Note that  <code class="code">nc</code> must be initialized prior to calling this function.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> 
if the extension is not present, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fext_005fimport_005fpolicies-1"><span>gnutls_x509_ext_import_policies<a class="copiable-link" href="#gnutls_005fx509_005fext_005fimport_005fpolicies-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fext_005fimport_005fpolicies"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fext_005fimport_005fpolicies"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_ext_import_policies</strong> <code class="def-code-arguments">(const gnutls_datum_t * <var class="var">ext</var>, gnutls_x509_policies_t <var class="var">policies</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fext_005fimport_005fpolicies"> &para;</a></span></dt>
<dd><p><var class="var">ext</var>: the DER encoded extension data
</p>
<p><var class="var">policies</var>: A pointer to an initialized policies.
</p>
<p><var class="var">flags</var>: should be zero
</p>
<p>This function will extract the certificate policy extension (2.5.29.32) 
and store it the provided policies.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fext_005fimport_005fprivate_005fkey_005fusage_005fperiod-1"><span>gnutls_x509_ext_import_private_key_usage_period<a class="copiable-link" href="#gnutls_005fx509_005fext_005fimport_005fprivate_005fkey_005fusage_005fperiod-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fext_005fimport_005fprivate_005fkey_005fusage_005fperiod"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fext_005fimport_005fprivate_005fkey_005fusage_005fperiod"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_ext_import_private_key_usage_period</strong> <code class="def-code-arguments">(const gnutls_datum_t * <var class="var">ext</var>, time_t * <var class="var">activation</var>, time_t * <var class="var">expiration</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fext_005fimport_005fprivate_005fkey_005fusage_005fperiod"> &para;</a></span></dt>
<dd><p><var class="var">ext</var>: the DER encoded extension data
</p>
<p><var class="var">activation</var>: Will hold the activation time
</p>
<p><var class="var">expiration</var>: Will hold the expiration time
</p>
<p>This function will return the expiration and activation
times of the private key as written in the
PKIX extension 2.5.29.16.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fext_005fimport_005fproxy-1"><span>gnutls_x509_ext_import_proxy<a class="copiable-link" href="#gnutls_005fx509_005fext_005fimport_005fproxy-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fext_005fimport_005fproxy"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fext_005fimport_005fproxy"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_ext_import_proxy</strong> <code class="def-code-arguments">(const gnutls_datum_t * <var class="var">ext</var>, int * <var class="var">pathlen</var>, char ** <var class="var">policyLanguage</var>, char ** <var class="var">policy</var>, size_t * <var class="var">sizeof_policy</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fext_005fimport_005fproxy"> &para;</a></span></dt>
<dd><p><var class="var">ext</var>: the DER encoded extension data
</p>
<p><var class="var">pathlen</var>: pointer to output integer indicating path length (may be
NULL), non-negative error codes indicate a present pCPathLenConstraint
field and the actual value, -1 indicate that the field is absent.
</p>
<p><var class="var">policyLanguage</var>: output variable with OID of policy language
</p>
<p><var class="var">policy</var>: output variable with policy data
</p>
<p><var class="var">sizeof_policy</var>: output variable with size of policy data
</p>
<p>This function will return the information from a proxy certificate
extension. It reads the ProxyCertInfo X.509 extension (1.3.6.1.5.5.7.1.14).
The  <code class="code">policyLanguage</code> and  <code class="code">policy</code> values must be deinitialized using <code class="code">gnutls_free()</code>  after use.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fext_005fimport_005fsubject_005falt_005fnames-1"><span>gnutls_x509_ext_import_subject_alt_names<a class="copiable-link" href="#gnutls_005fx509_005fext_005fimport_005fsubject_005falt_005fnames-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fext_005fimport_005fsubject_005falt_005fnames"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fext_005fimport_005fsubject_005falt_005fnames"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_ext_import_subject_alt_names</strong> <code class="def-code-arguments">(const gnutls_datum_t * <var class="var">ext</var>, gnutls_subject_alt_names_t <var class="var">sans</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fext_005fimport_005fsubject_005falt_005fnames"> &para;</a></span></dt>
<dd><p><var class="var">ext</var>: The DER-encoded extension data
</p>
<p><var class="var">sans</var>: The alternative names
</p>
<p><var class="var">flags</var>: should be zero
</p>
<p>This function will export the alternative names in the provided DER-encoded
SubjectAltName PKIX extension, to a <code class="code">gnutls_subject_alt_names_t</code>  type.  <code class="code">sans</code> must be initialized.
</p>
<p>This function will succeed even if there no subject alternative names
in the structure.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fext_005fimport_005fsubject_005fkey_005fid-1"><span>gnutls_x509_ext_import_subject_key_id<a class="copiable-link" href="#gnutls_005fx509_005fext_005fimport_005fsubject_005fkey_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fext_005fimport_005fsubject_005fkey_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fext_005fimport_005fsubject_005fkey_005fid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_ext_import_subject_key_id</strong> <code class="def-code-arguments">(const gnutls_datum_t * <var class="var">ext</var>, gnutls_datum_t * <var class="var">id</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fext_005fimport_005fsubject_005fkey_005fid"> &para;</a></span></dt>
<dd><p><var class="var">ext</var>: a DER encoded extension
</p>
<p><var class="var">id</var>: will contain the subject key ID
</p>
<p>This function will return the subject key ID stored in the provided
SubjectKeyIdentifier extension. The ID will be allocated using
<code class="code">gnutls_malloc()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> 
if the extension is not present, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fext_005fimport_005ftlsfeatures-1"><span>gnutls_x509_ext_import_tlsfeatures<a class="copiable-link" href="#gnutls_005fx509_005fext_005fimport_005ftlsfeatures-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fext_005fimport_005ftlsfeatures"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fext_005fimport_005ftlsfeatures"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_ext_import_tlsfeatures</strong> <code class="def-code-arguments">(const gnutls_datum_t * <var class="var">ext</var>, gnutls_x509_tlsfeatures_t <var class="var">f</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fext_005fimport_005ftlsfeatures"> &para;</a></span></dt>
<dd><p><var class="var">ext</var>: The DER-encoded extension data
</p>
<p><var class="var">f</var>: The features structure
</p>
<p><var class="var">flags</var>: zero or <code class="code">GNUTLS_EXT_FLAG_APPEND</code> 
</p>
<p>This function will export the features in the provided DER-encoded
TLS Features PKIX extension, to a <code class="code">gnutls_x509_tlsfeatures_t</code>  type.  <code class="code">f</code> must be initialized.
</p>
<p>When the  <code class="code">flags</code> is set to <code class="code">GNUTLS_EXT_FLAG_APPEND</code> ,
then if the  <code class="code">features</code> structure is empty this function will behave
identically as if the flag was not set. Otherwise if there are elements 
in the  <code class="code">features</code> structure then they will be merged with.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.5.1
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fext_005fprint-1"><span>gnutls_x509_ext_print<a class="copiable-link" href="#gnutls_005fx509_005fext_005fprint-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fext_005fprint"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fext_005fprint"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_ext_print</strong> <code class="def-code-arguments">(gnutls_x509_ext_st * <var class="var">exts</var>, unsigned int <var class="var">exts_size</var>, gnutls_certificate_print_formats_t <var class="var">format</var>, gnutls_datum_t * <var class="var">out</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fext_005fprint"> &para;</a></span></dt>
<dd><p><var class="var">exts</var>: The data to be printed
</p>
<p><var class="var">exts_size</var>: the number of available structures
</p>
<p><var class="var">format</var>: Indicate the format to use
</p>
<p><var class="var">out</var>: Newly allocated datum with null terminated string.
</p>
<p>This function will pretty print X.509 certificate extensions,
suitable for display to a human.
</p>
<p>The output  <code class="code">out</code> needs to be deallocated using <code class="code">gnutls_free()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fkey_005fpurpose_005fdeinit-1"><span>gnutls_x509_key_purpose_deinit<a class="copiable-link" href="#gnutls_005fx509_005fkey_005fpurpose_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fkey_005fpurpose_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fkey_005fpurpose_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_x509_key_purpose_deinit</strong> <code class="def-code-arguments">(gnutls_x509_key_purposes_t <var class="var">p</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fkey_005fpurpose_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">p</var>: The key purposes
</p>
<p>This function will deinitialize a key purposes type.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fkey_005fpurpose_005fget-1"><span>gnutls_x509_key_purpose_get<a class="copiable-link" href="#gnutls_005fx509_005fkey_005fpurpose_005fget-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fkey_005fpurpose_005fget"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fkey_005fpurpose_005fget"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_key_purpose_get</strong> <code class="def-code-arguments">(gnutls_x509_key_purposes_t <var class="var">p</var>, unsigned <var class="var">idx</var>, gnutls_datum_t * <var class="var">oid</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fkey_005fpurpose_005fget"> &para;</a></span></dt>
<dd><p><var class="var">p</var>: The key purposes
</p>
<p><var class="var">idx</var>: The index of the key purpose to retrieve
</p>
<p><var class="var">oid</var>: Will hold the object identifier of the key purpose (to be treated as constant)
</p>
<p>This function will retrieve the specified by the index key purpose in the
purposes type. The object identifier will be a null terminated string.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> 
if the index is out of bounds, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fkey_005fpurpose_005finit-1"><span>gnutls_x509_key_purpose_init<a class="copiable-link" href="#gnutls_005fx509_005fkey_005fpurpose_005finit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fkey_005fpurpose_005finit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fkey_005fpurpose_005finit"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_key_purpose_init</strong> <code class="def-code-arguments">(gnutls_x509_key_purposes_t * <var class="var">p</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fkey_005fpurpose_005finit"> &para;</a></span></dt>
<dd><p><var class="var">p</var>: The key purposes
</p>
<p>This function will initialize an alternative names type.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fkey_005fpurpose_005fset-1"><span>gnutls_x509_key_purpose_set<a class="copiable-link" href="#gnutls_005fx509_005fkey_005fpurpose_005fset-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fkey_005fpurpose_005fset"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fkey_005fpurpose_005fset"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_key_purpose_set</strong> <code class="def-code-arguments">(gnutls_x509_key_purposes_t <var class="var">p</var>, const char * <var class="var">oid</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fkey_005fpurpose_005fset"> &para;</a></span></dt>
<dd><p><var class="var">p</var>: The key purposes
</p>
<p><var class="var">oid</var>: The object identifier of the key purpose
</p>
<p>This function will store the specified key purpose in the
purposes.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0), otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fname_005fconstraints_005fadd_005fexcluded-1"><span>gnutls_x509_name_constraints_add_excluded<a class="copiable-link" href="#gnutls_005fx509_005fname_005fconstraints_005fadd_005fexcluded-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fname_005fconstraints_005fadd_005fexcluded"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fname_005fconstraints_005fadd_005fexcluded"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_name_constraints_add_excluded</strong> <code class="def-code-arguments">(gnutls_x509_name_constraints_t <var class="var">nc</var>, gnutls_x509_subject_alt_name_t <var class="var">type</var>, const gnutls_datum_t * <var class="var">name</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fname_005fconstraints_005fadd_005fexcluded"> &para;</a></span></dt>
<dd><p><var class="var">nc</var>: The nameconstraints
</p>
<p><var class="var">type</var>: The type of the constraints
</p>
<p><var class="var">name</var>: The data of the constraints
</p>
<p>This function will add a name constraint to the list of excluded
constraints. The constraints  <code class="code">type</code> can be any of the following types:
<code class="code">GNUTLS_SAN_DNSNAME</code> , <code class="code">GNUTLS_SAN_RFC822NAME</code> , <code class="code">GNUTLS_SAN_DN</code> ,
<code class="code">GNUTLS_SAN_URI</code> , <code class="code">GNUTLS_SAN_IPADDRESS</code> . For the latter, an IP address
in network byte order is expected, followed by its network mask (which is
4 bytes in IPv4 or 16-bytes in IPv6).
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fname_005fconstraints_005fadd_005fpermitted-1"><span>gnutls_x509_name_constraints_add_permitted<a class="copiable-link" href="#gnutls_005fx509_005fname_005fconstraints_005fadd_005fpermitted-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fname_005fconstraints_005fadd_005fpermitted"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fname_005fconstraints_005fadd_005fpermitted"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_name_constraints_add_permitted</strong> <code class="def-code-arguments">(gnutls_x509_name_constraints_t <var class="var">nc</var>, gnutls_x509_subject_alt_name_t <var class="var">type</var>, const gnutls_datum_t * <var class="var">name</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fname_005fconstraints_005fadd_005fpermitted"> &para;</a></span></dt>
<dd><p><var class="var">nc</var>: The nameconstraints
</p>
<p><var class="var">type</var>: The type of the constraints
</p>
<p><var class="var">name</var>: The data of the constraints
</p>
<p>This function will add a name constraint to the list of permitted
constraints. The constraints  <code class="code">type</code> can be any of the following types:
<code class="code">GNUTLS_SAN_DNSNAME</code> , <code class="code">GNUTLS_SAN_RFC822NAME</code> , <code class="code">GNUTLS_SAN_DN</code> ,
<code class="code">GNUTLS_SAN_URI</code> , <code class="code">GNUTLS_SAN_IPADDRESS</code> . For the latter, an IP address
in network byte order is expected, followed by its network mask.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fname_005fconstraints_005fcheck-1"><span>gnutls_x509_name_constraints_check<a class="copiable-link" href="#gnutls_005fx509_005fname_005fconstraints_005fcheck-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fname_005fconstraints_005fcheck"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fname_005fconstraints_005fcheck"><span class="category-def">Function: </span><span><code class="def-type">unsigned</code> <strong class="def-name">gnutls_x509_name_constraints_check</strong> <code class="def-code-arguments">(gnutls_x509_name_constraints_t <var class="var">nc</var>, gnutls_x509_subject_alt_name_t <var class="var">type</var>, const gnutls_datum_t * <var class="var">name</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fname_005fconstraints_005fcheck"> &para;</a></span></dt>
<dd><p><var class="var">nc</var>: the extracted name constraints
</p>
<p><var class="var">type</var>: the type of the constraint to check (of type gnutls_x509_subject_alt_name_t)
</p>
<p><var class="var">name</var>: the name to be checked
</p>
<p>This function will check the provided name against the constraints in
 <code class="code">nc</code> using the RFC5280 rules. Currently this function is limited to DNS
names, emails and IP addresses (of type <code class="code">GNUTLS_SAN_DNSNAME</code> ,
<code class="code">GNUTLS_SAN_RFC822NAME</code>  and <code class="code">GNUTLS_SAN_IPADDRESS</code> ).
</p>
<p><strong class="strong">Returns:</strong> zero if the provided name is not acceptable, and non-zero otherwise.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fname_005fconstraints_005fcheck_005fcrt-1"><span>gnutls_x509_name_constraints_check_crt<a class="copiable-link" href="#gnutls_005fx509_005fname_005fconstraints_005fcheck_005fcrt-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fname_005fconstraints_005fcheck_005fcrt"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fname_005fconstraints_005fcheck_005fcrt"><span class="category-def">Function: </span><span><code class="def-type">unsigned</code> <strong class="def-name">gnutls_x509_name_constraints_check_crt</strong> <code class="def-code-arguments">(gnutls_x509_name_constraints_t <var class="var">nc</var>, gnutls_x509_subject_alt_name_t <var class="var">type</var>, gnutls_x509_crt_t <var class="var">cert</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fname_005fconstraints_005fcheck_005fcrt"> &para;</a></span></dt>
<dd><p><var class="var">nc</var>: the extracted name constraints
</p>
<p><var class="var">type</var>: the type of the constraint to check (of type gnutls_x509_subject_alt_name_t)
</p>
<p><var class="var">cert</var>: the certificate to be checked
</p>
<p>This function will check the provided certificate names against the constraints in
 <code class="code">nc</code> using the RFC5280 rules. It will traverse all the certificate&rsquo;s names and
alternative names.
</p>
<p>Currently this function is limited to DNS
names and emails (of type <code class="code">GNUTLS_SAN_DNSNAME</code>  and <code class="code">GNUTLS_SAN_RFC822NAME</code> ).
</p>
<p><strong class="strong">Returns:</strong> zero if the provided name is not acceptable, and non-zero otherwise.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fname_005fconstraints_005fdeinit-1"><span>gnutls_x509_name_constraints_deinit<a class="copiable-link" href="#gnutls_005fx509_005fname_005fconstraints_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fname_005fconstraints_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fname_005fconstraints_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_x509_name_constraints_deinit</strong> <code class="def-code-arguments">(gnutls_x509_name_constraints_t <var class="var">nc</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fname_005fconstraints_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">nc</var>: The nameconstraints
</p>
<p>This function will deinitialize a name constraints type.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fname_005fconstraints_005fget_005fexcluded-1"><span>gnutls_x509_name_constraints_get_excluded<a class="copiable-link" href="#gnutls_005fx509_005fname_005fconstraints_005fget_005fexcluded-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fname_005fconstraints_005fget_005fexcluded"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fname_005fconstraints_005fget_005fexcluded"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_name_constraints_get_excluded</strong> <code class="def-code-arguments">(gnutls_x509_name_constraints_t <var class="var">nc</var>, unsigned <var class="var">idx</var>, unsigned * <var class="var">type</var>, gnutls_datum_t * <var class="var">name</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fname_005fconstraints_005fget_005fexcluded"> &para;</a></span></dt>
<dd><p><var class="var">nc</var>: the extracted name constraints
</p>
<p><var class="var">idx</var>: the index of the constraint
</p>
<p><var class="var">type</var>: the type of the constraint (of type gnutls_x509_subject_alt_name_t)
</p>
<p><var class="var">name</var>: the name in the constraint (of the specific type)
</p>
<p>This function will return an intermediate type containing
the name constraints of the provided CA certificate. That
structure can be used in combination with <code class="code">gnutls_x509_name_constraints_check()</code> 
to verify whether a server&rsquo;s name is in accordance with the constraints.
</p>
<p>The name should be treated as constant and valid for the lifetime of  <code class="code">nc</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> 
if the extension is not present, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fname_005fconstraints_005fget_005fpermitted-1"><span>gnutls_x509_name_constraints_get_permitted<a class="copiable-link" href="#gnutls_005fx509_005fname_005fconstraints_005fget_005fpermitted-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fname_005fconstraints_005fget_005fpermitted"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fname_005fconstraints_005fget_005fpermitted"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_name_constraints_get_permitted</strong> <code class="def-code-arguments">(gnutls_x509_name_constraints_t <var class="var">nc</var>, unsigned <var class="var">idx</var>, unsigned * <var class="var">type</var>, gnutls_datum_t * <var class="var">name</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fname_005fconstraints_005fget_005fpermitted"> &para;</a></span></dt>
<dd><p><var class="var">nc</var>: the extracted name constraints
</p>
<p><var class="var">idx</var>: the index of the constraint
</p>
<p><var class="var">type</var>: the type of the constraint (of type gnutls_x509_subject_alt_name_t)
</p>
<p><var class="var">name</var>: the name in the constraint (of the specific type)
</p>
<p>This function will return an intermediate type containing
the name constraints of the provided CA certificate. That
structure can be used in combination with <code class="code">gnutls_x509_name_constraints_check()</code> 
to verify whether a server&rsquo;s name is in accordance with the constraints.
</p>
<p>The name should be treated as constant and valid for the lifetime of  <code class="code">nc</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> 
if the extension is not present, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fname_005fconstraints_005finit-1"><span>gnutls_x509_name_constraints_init<a class="copiable-link" href="#gnutls_005fx509_005fname_005fconstraints_005finit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fname_005fconstraints_005finit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fname_005fconstraints_005finit"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_name_constraints_init</strong> <code class="def-code-arguments">(gnutls_x509_name_constraints_t * <var class="var">nc</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fname_005fconstraints_005finit"> &para;</a></span></dt>
<dd><p><var class="var">nc</var>: The nameconstraints
</p>
<p>This function will initialize a name constraints type.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fothername_005fto_005fvirtual-1"><span>gnutls_x509_othername_to_virtual<a class="copiable-link" href="#gnutls_005fx509_005fothername_005fto_005fvirtual-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fothername_005fto_005fvirtual"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fothername_005fto_005fvirtual"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_othername_to_virtual</strong> <code class="def-code-arguments">(const char * <var class="var">oid</var>, const gnutls_datum_t * <var class="var">othername</var>, unsigned int * <var class="var">virt_type</var>, gnutls_datum_t * <var class="var">virt</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fothername_005fto_005fvirtual"> &para;</a></span></dt>
<dd><p><var class="var">oid</var>: The othername object identifier
</p>
<p><var class="var">othername</var>: The othername data
</p>
<p><var class="var">virt_type</var>: GNUTLS_SAN_OTHERNAME_XXX
</p>
<p><var class="var">virt</var>: allocated printable data
</p>
<p>This function will parse and convert the othername data to a virtual
type supported by gnutls.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.8
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fpolicies_005fdeinit-1"><span>gnutls_x509_policies_deinit<a class="copiable-link" href="#gnutls_005fx509_005fpolicies_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fpolicies_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fpolicies_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_x509_policies_deinit</strong> <code class="def-code-arguments">(gnutls_x509_policies_t <var class="var">policies</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fpolicies_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">policies</var>: The authority key identifier
</p>
<p>This function will deinitialize an authority key identifier type.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fpolicies_005fget-1"><span>gnutls_x509_policies_get<a class="copiable-link" href="#gnutls_005fx509_005fpolicies_005fget-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fpolicies_005fget"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fpolicies_005fget"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_policies_get</strong> <code class="def-code-arguments">(gnutls_x509_policies_t <var class="var">policies</var>, unsigned int <var class="var">seq</var>, struct gnutls_x509_policy_st * <var class="var">policy</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fpolicies_005fget"> &para;</a></span></dt>
<dd><p><var class="var">policies</var>: The policies
</p>
<p><var class="var">seq</var>: The index of the name to get
</p>
<p><var class="var">policy</var>: Will hold the policy
</p>
<p>This function will return a specific policy as stored in
the  <code class="code">policies</code> type. The returned values should be treated as constant
and valid for the lifetime of  <code class="code">policies</code> .
</p>
<p>The any policy OID is available as the <code class="code">GNUTLS_X509_OID_POLICY_ANY</code>  macro.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> 
if the index is out of bounds, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fpolicies_005finit-1"><span>gnutls_x509_policies_init<a class="copiable-link" href="#gnutls_005fx509_005fpolicies_005finit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fpolicies_005finit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fpolicies_005finit"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_policies_init</strong> <code class="def-code-arguments">(gnutls_x509_policies_t * <var class="var">policies</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fpolicies_005finit"> &para;</a></span></dt>
<dd><p><var class="var">policies</var>: The authority key ID
</p>
<p>This function will initialize an authority key ID type.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fpolicies_005fset-1"><span>gnutls_x509_policies_set<a class="copiable-link" href="#gnutls_005fx509_005fpolicies_005fset-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fpolicies_005fset"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fpolicies_005fset"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_policies_set</strong> <code class="def-code-arguments">(gnutls_x509_policies_t <var class="var">policies</var>, const struct gnutls_x509_policy_st * <var class="var">policy</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fpolicies_005fset"> &para;</a></span></dt>
<dd><p><var class="var">policies</var>: An initialized policies
</p>
<p><var class="var">policy</var>: Contains the policy to set
</p>
<p>This function will store the specified policy in
the provided  <code class="code">policies</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0), otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fpolicy_005frelease-1"><span>gnutls_x509_policy_release<a class="copiable-link" href="#gnutls_005fx509_005fpolicy_005frelease-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fpolicy_005frelease"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fpolicy_005frelease"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_x509_policy_release</strong> <code class="def-code-arguments">(struct gnutls_x509_policy_st * <var class="var">policy</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fpolicy_005frelease"> &para;</a></span></dt>
<dd><p><var class="var">policy</var>: a certificate policy
</p>
<p>This function will deinitialize all memory associated with the provided
 <code class="code">policy</code> . The policy is allocated using <code class="code">gnutls_x509_crt_get_policy()</code> .
</p>
<p><strong class="strong">Since:</strong> 3.1.5
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fprivkey_005fcpy-1"><span>gnutls_x509_privkey_cpy<a class="copiable-link" href="#gnutls_005fx509_005fprivkey_005fcpy-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fprivkey_005fcpy"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fprivkey_005fcpy"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_privkey_cpy</strong> <code class="def-code-arguments">(gnutls_x509_privkey_t <var class="var">dst</var>, gnutls_x509_privkey_t <var class="var">src</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fprivkey_005fcpy"> &para;</a></span></dt>
<dd><p><var class="var">dst</var>: The destination key, which should be initialized.
</p>
<p><var class="var">src</var>: The source key
</p>
<p>This function will copy a private key from source to destination
key. Destination has to be initialized.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fprivkey_005fdeinit-1"><span>gnutls_x509_privkey_deinit<a class="copiable-link" href="#gnutls_005fx509_005fprivkey_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fprivkey_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fprivkey_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_x509_privkey_deinit</strong> <code class="def-code-arguments">(gnutls_x509_privkey_t <var class="var">key</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fprivkey_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: The key to be deinitialized
</p>
<p>This function will deinitialize a private key structure.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fprivkey_005fexport-1"><span>gnutls_x509_privkey_export<a class="copiable-link" href="#gnutls_005fx509_005fprivkey_005fexport-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fprivkey_005fexport"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fprivkey_005fexport"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_privkey_export</strong> <code class="def-code-arguments">(gnutls_x509_privkey_t <var class="var">key</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, void * <var class="var">output_data</var>, size_t * <var class="var">output_data_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fprivkey_005fexport"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: Holds the key
</p>
<p><var class="var">format</var>: the format of output params. One of PEM or DER.
</p>
<p><var class="var">output_data</var>: will contain a private key PEM or DER encoded
</p>
<p><var class="var">output_data_size</var>: holds the size of output_data (and will be
replaced by the actual size of parameters)
</p>
<p>This function will export the private key to a PKCS<code class="code">1</code>  structure for
RSA or RSA-PSS keys, and integer sequence for DSA keys. Other keys types
will be exported in PKCS<code class="code">8</code>  form.
</p>
<p>If the structure is PEM encoded, it will have a header
of &quot;BEGIN RSA PRIVATE KEY&quot;.
</p>
<p>It is recommended to use <code class="code">gnutls_x509_privkey_export_pkcs8()</code>  instead
of this function, when a consistent output format is required.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fprivkey_005fexport2-1"><span>gnutls_x509_privkey_export2<a class="copiable-link" href="#gnutls_005fx509_005fprivkey_005fexport2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fprivkey_005fexport2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fprivkey_005fexport2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_privkey_export2</strong> <code class="def-code-arguments">(gnutls_x509_privkey_t <var class="var">key</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, gnutls_datum_t * <var class="var">out</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fprivkey_005fexport2"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: Holds the key
</p>
<p><var class="var">format</var>: the format of output params. One of PEM or DER.
</p>
<p><var class="var">out</var>: will contain a private key PEM or DER encoded
</p>
<p>This function will export the private key to a PKCS<code class="code">1</code>  structure for
RSA or RSA-PSS keys, and integer sequence for DSA keys. Other keys types
will be exported in PKCS<code class="code">8</code>  form.
</p>
<p>The output buffer is allocated using <code class="code">gnutls_malloc()</code> .
</p>
<p>It is recommended to use <code class="code">gnutls_x509_privkey_export2_pkcs8()</code>  instead
of this function, when a consistent output format is required.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p>Since 3.1.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fprivkey_005fexport2_005fpkcs8-1"><span>gnutls_x509_privkey_export2_pkcs8<a class="copiable-link" href="#gnutls_005fx509_005fprivkey_005fexport2_005fpkcs8-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fprivkey_005fexport2_005fpkcs8"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fprivkey_005fexport2_005fpkcs8"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_privkey_export2_pkcs8</strong> <code class="def-code-arguments">(gnutls_x509_privkey_t <var class="var">key</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, const char * <var class="var">password</var>, unsigned int <var class="var">flags</var>, gnutls_datum_t * <var class="var">out</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fprivkey_005fexport2_005fpkcs8"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: Holds the key
</p>
<p><var class="var">format</var>: the format of output params. One of PEM or DER.
</p>
<p><var class="var">password</var>: the password that will be used to encrypt the key.
</p>
<p><var class="var">flags</var>: an ORed sequence of gnutls_pkcs_encrypt_flags_t
</p>
<p><var class="var">out</var>: will contain a private key PEM or DER encoded
</p>
<p>This function will export the private key to a PKCS8 structure.
Both RSA and DSA keys can be exported. For DSA keys we use
PKCS <code class="code">11</code>  definitions. If the flags do not specify the encryption
cipher, then the default 3DES (PBES2) will be used.
</p>
<p>The  <code class="code">password</code> can be either ASCII or UTF-8 in the default PBES2
encryption schemas, or ASCII for the PKCS12 schemas.
</p>
<p>The output buffer is allocated using <code class="code">gnutls_malloc()</code> .
</p>
<p>If the structure is PEM encoded, it will have a header
of &quot;BEGIN ENCRYPTED PRIVATE KEY&quot; or &quot;BEGIN PRIVATE KEY&quot; if
encryption is not used.
</p>
<p><strong class="strong">Returns:</strong> In case of failure a negative error code will be
returned, and 0 on success.
</p>
<p>Since 3.1.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fprivkey_005fexport_005fdsa_005fraw-1"><span>gnutls_x509_privkey_export_dsa_raw<a class="copiable-link" href="#gnutls_005fx509_005fprivkey_005fexport_005fdsa_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fprivkey_005fexport_005fdsa_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fprivkey_005fexport_005fdsa_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_privkey_export_dsa_raw</strong> <code class="def-code-arguments">(gnutls_x509_privkey_t <var class="var">key</var>, gnutls_datum_t * <var class="var">p</var>, gnutls_datum_t * <var class="var">q</var>, gnutls_datum_t * <var class="var">g</var>, gnutls_datum_t * <var class="var">y</var>, gnutls_datum_t * <var class="var">x</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fprivkey_005fexport_005fdsa_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: a key
</p>
<p><var class="var">p</var>: will hold the p
</p>
<p><var class="var">q</var>: will hold the q
</p>
<p><var class="var">g</var>: will hold the g
</p>
<p><var class="var">y</var>: will hold the y
</p>
<p><var class="var">x</var>: will hold the x
</p>
<p>This function will export the DSA private key&rsquo;s parameters found
in the given structure. The new parameters will be allocated using
<code class="code">gnutls_malloc()</code>  and will be stored in the appropriate datum.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fprivkey_005fexport_005fecc_005fraw-1"><span>gnutls_x509_privkey_export_ecc_raw<a class="copiable-link" href="#gnutls_005fx509_005fprivkey_005fexport_005fecc_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fprivkey_005fexport_005fecc_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fprivkey_005fexport_005fecc_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_privkey_export_ecc_raw</strong> <code class="def-code-arguments">(gnutls_x509_privkey_t <var class="var">key</var>, gnutls_ecc_curve_t * <var class="var">curve</var>, gnutls_datum_t * <var class="var">x</var>, gnutls_datum_t * <var class="var">y</var>, gnutls_datum_t * <var class="var">k</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fprivkey_005fexport_005fecc_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: a key
</p>
<p><var class="var">curve</var>: will hold the curve
</p>
<p><var class="var">x</var>: will hold the x-coordinate
</p>
<p><var class="var">y</var>: will hold the y-coordinate
</p>
<p><var class="var">k</var>: will hold the private key
</p>
<p>This function will export the ECC private key&rsquo;s parameters found
in the given structure. The new parameters will be allocated using
<code class="code">gnutls_malloc()</code>  and will be stored in the appropriate datum.
</p>
<p>In EdDSA curves the  <code class="code">y</code> parameter will be <code class="code">NULL</code>  and the other parameters
will be in the native format for the curve.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fprivkey_005fexport_005fgost_005fraw-1"><span>gnutls_x509_privkey_export_gost_raw<a class="copiable-link" href="#gnutls_005fx509_005fprivkey_005fexport_005fgost_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fprivkey_005fexport_005fgost_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fprivkey_005fexport_005fgost_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_privkey_export_gost_raw</strong> <code class="def-code-arguments">(gnutls_x509_privkey_t <var class="var">key</var>, gnutls_ecc_curve_t * <var class="var">curve</var>, gnutls_digest_algorithm_t * <var class="var">digest</var>, gnutls_gost_paramset_t * <var class="var">paramset</var>, gnutls_datum_t * <var class="var">x</var>, gnutls_datum_t * <var class="var">y</var>, gnutls_datum_t * <var class="var">k</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fprivkey_005fexport_005fgost_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: a key
</p>
<p><var class="var">curve</var>: will hold the curve
</p>
<p><var class="var">digest</var>: will hold the digest
</p>
<p><var class="var">paramset</var>: will hold the GOST parameter set ID
</p>
<p><var class="var">x</var>: will hold the x-coordinate
</p>
<p><var class="var">y</var>: will hold the y-coordinate
</p>
<p><var class="var">k</var>: will hold the private key
</p>
<p>This function will export the GOST private key&rsquo;s parameters found
in the given structure. The new parameters will be allocated using
<code class="code">gnutls_malloc()</code>  and will be stored in the appropriate datum.
</p>
<p><strong class="strong">Note:</strong> parameters will be stored with least significant byte first. On
version 3.6.3 this was incorrectly returned in big-endian format.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.6.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fprivkey_005fexport_005fpkcs8-1"><span>gnutls_x509_privkey_export_pkcs8<a class="copiable-link" href="#gnutls_005fx509_005fprivkey_005fexport_005fpkcs8-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fprivkey_005fexport_005fpkcs8"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fprivkey_005fexport_005fpkcs8"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_privkey_export_pkcs8</strong> <code class="def-code-arguments">(gnutls_x509_privkey_t <var class="var">key</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, const char * <var class="var">password</var>, unsigned int <var class="var">flags</var>, void * <var class="var">output_data</var>, size_t * <var class="var">output_data_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fprivkey_005fexport_005fpkcs8"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: Holds the key
</p>
<p><var class="var">format</var>: the format of output params. One of PEM or DER.
</p>
<p><var class="var">password</var>: the password that will be used to encrypt the key.
</p>
<p><var class="var">flags</var>: an ORed sequence of gnutls_pkcs_encrypt_flags_t
</p>
<p><var class="var">output_data</var>: will contain a private key PEM or DER encoded
</p>
<p><var class="var">output_data_size</var>: holds the size of output_data (and will be
replaced by the actual size of parameters)
</p>
<p>This function will export the private key to a PKCS8 structure.
Both RSA and DSA keys can be exported. For DSA keys we use
PKCS <code class="code">11</code>  definitions. If the flags do not specify the encryption
cipher, then the default 3DES (PBES2) will be used.
</p>
<p>The  <code class="code">password</code> can be either ASCII or UTF-8 in the default PBES2
encryption schemas, or ASCII for the PKCS12 schemas.
</p>
<p>If the buffer provided is not long enough to hold the output, then
*output_data_size is updated and GNUTLS_E_SHORT_MEMORY_BUFFER will
be returned.
</p>
<p>If the structure is PEM encoded, it will have a header
of &quot;BEGIN ENCRYPTED PRIVATE KEY&quot; or &quot;BEGIN PRIVATE KEY&quot; if
encryption is not used.
</p>
<p><strong class="strong">Returns:</strong> In case of failure a negative error code will be
returned, and 0 on success.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fprivkey_005fexport_005frsa_005fraw-1"><span>gnutls_x509_privkey_export_rsa_raw<a class="copiable-link" href="#gnutls_005fx509_005fprivkey_005fexport_005frsa_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fprivkey_005fexport_005frsa_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fprivkey_005fexport_005frsa_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_privkey_export_rsa_raw</strong> <code class="def-code-arguments">(gnutls_x509_privkey_t <var class="var">key</var>, gnutls_datum_t * <var class="var">m</var>, gnutls_datum_t * <var class="var">e</var>, gnutls_datum_t * <var class="var">d</var>, gnutls_datum_t * <var class="var">p</var>, gnutls_datum_t * <var class="var">q</var>, gnutls_datum_t * <var class="var">u</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fprivkey_005fexport_005frsa_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: a key
</p>
<p><var class="var">m</var>: will hold the modulus
</p>
<p><var class="var">e</var>: will hold the public exponent
</p>
<p><var class="var">d</var>: will hold the private exponent
</p>
<p><var class="var">p</var>: will hold the first prime (p)
</p>
<p><var class="var">q</var>: will hold the second prime (q)
</p>
<p><var class="var">u</var>: will hold the coefficient
</p>
<p>This function will export the RSA private key&rsquo;s parameters found
in the given structure. The new parameters will be allocated using
<code class="code">gnutls_malloc()</code>  and will be stored in the appropriate datum.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fprivkey_005fexport_005frsa_005fraw2-1"><span>gnutls_x509_privkey_export_rsa_raw2<a class="copiable-link" href="#gnutls_005fx509_005fprivkey_005fexport_005frsa_005fraw2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fprivkey_005fexport_005frsa_005fraw2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fprivkey_005fexport_005frsa_005fraw2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_privkey_export_rsa_raw2</strong> <code class="def-code-arguments">(gnutls_x509_privkey_t <var class="var">key</var>, gnutls_datum_t * <var class="var">m</var>, gnutls_datum_t * <var class="var">e</var>, gnutls_datum_t * <var class="var">d</var>, gnutls_datum_t * <var class="var">p</var>, gnutls_datum_t * <var class="var">q</var>, gnutls_datum_t * <var class="var">u</var>, gnutls_datum_t * <var class="var">e1</var>, gnutls_datum_t * <var class="var">e2</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fprivkey_005fexport_005frsa_005fraw2"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: a key
</p>
<p><var class="var">m</var>: will hold the modulus
</p>
<p><var class="var">e</var>: will hold the public exponent
</p>
<p><var class="var">d</var>: will hold the private exponent
</p>
<p><var class="var">p</var>: will hold the first prime (p)
</p>
<p><var class="var">q</var>: will hold the second prime (q)
</p>
<p><var class="var">u</var>: will hold the coefficient
</p>
<p><var class="var">e1</var>: will hold e1 = d mod (p-1)
</p>
<p><var class="var">e2</var>: will hold e2 = d mod (q-1)
</p>
<p>This function will export the RSA private key&rsquo;s parameters found
in the given structure. The new parameters will be allocated using
<code class="code">gnutls_malloc()</code>  and will be stored in the appropriate datum.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fprivkey_005ffix-1"><span>gnutls_x509_privkey_fix<a class="copiable-link" href="#gnutls_005fx509_005fprivkey_005ffix-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fprivkey_005ffix"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fprivkey_005ffix"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_privkey_fix</strong> <code class="def-code-arguments">(gnutls_x509_privkey_t <var class="var">key</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fprivkey_005ffix"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: a key
</p>
<p>This function will recalculate the secondary parameters in a key.
In RSA keys, this can be the coefficient and exponent1,2.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fprivkey_005fgenerate-1"><span>gnutls_x509_privkey_generate<a class="copiable-link" href="#gnutls_005fx509_005fprivkey_005fgenerate-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fprivkey_005fgenerate"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fprivkey_005fgenerate"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_privkey_generate</strong> <code class="def-code-arguments">(gnutls_x509_privkey_t <var class="var">key</var>, gnutls_pk_algorithm_t <var class="var">algo</var>, unsigned int <var class="var">bits</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fprivkey_005fgenerate"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: an initialized key
</p>
<p><var class="var">algo</var>: is one of the algorithms in <code class="code">gnutls_pk_algorithm_t</code> .
</p>
<p><var class="var">bits</var>: the size of the parameters to generate
</p>
<p><var class="var">flags</var>: Must be zero or flags from <code class="code">gnutls_privkey_flags_t</code> .
</p>
<p>This function will generate a random private key. Note that this
function must be called on an initialized private key.
</p>
<p>The flag <code class="code">GNUTLS_PRIVKEY_FLAG_PROVABLE</code> 
instructs the key generation process to use algorithms like Shawe-Taylor
(from FIPS PUB186-4) which generate provable parameters out of a seed
for RSA and DSA keys. See <code class="code">gnutls_x509_privkey_generate2()</code>  for more
information.
</p>
<p>Note that when generating an elliptic curve key, the curve
can be substituted in the place of the bits parameter using the
<code class="code">GNUTLS_CURVE_TO_BITS()</code>  macro. The input to the macro is any curve from
<code class="code">gnutls_ecc_curve_t</code> .
</p>
<p>For DSA keys, if the subgroup size needs to be specified check
the <code class="code">GNUTLS_SUBGROUP_TO_BITS()</code>  macro.
</p>
<p>It is recommended to do not set the number of  <code class="code">bits</code> directly, use <code class="code">gnutls_sec_param_to_pk_bits()</code>  instead .
</p>
<p>See also <code class="code">gnutls_privkey_generate()</code> , <code class="code">gnutls_x509_privkey_generate2()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fprivkey_005fgenerate2-1"><span>gnutls_x509_privkey_generate2<a class="copiable-link" href="#gnutls_005fx509_005fprivkey_005fgenerate2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fprivkey_005fgenerate2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fprivkey_005fgenerate2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_privkey_generate2</strong> <code class="def-code-arguments">(gnutls_x509_privkey_t <var class="var">key</var>, gnutls_pk_algorithm_t <var class="var">algo</var>, unsigned int <var class="var">bits</var>, unsigned int <var class="var">flags</var>, const gnutls_keygen_data_st * <var class="var">data</var>, unsigned <var class="var">data_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fprivkey_005fgenerate2"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: a key
</p>
<p><var class="var">algo</var>: is one of the algorithms in <code class="code">gnutls_pk_algorithm_t</code> .
</p>
<p><var class="var">bits</var>: the size of the modulus
</p>
<p><var class="var">flags</var>: Must be zero or flags from <code class="code">gnutls_privkey_flags_t</code> .
</p>
<p><var class="var">data</var>: Allow specifying <code class="code">gnutls_keygen_data_st</code>  types such as the seed to be used.
</p>
<p><var class="var">data_size</var>: The number of  <code class="code">data</code> available.
</p>
<p>This function will generate a random private key. Note that this
function must be called on an initialized private key.
</p>
<p>The flag <code class="code">GNUTLS_PRIVKEY_FLAG_PROVABLE</code> 
instructs the key generation process to use algorithms like Shawe-Taylor
(from FIPS PUB186-4) which generate provable parameters out of a seed
for RSA and DSA keys. On DSA keys the PQG parameters are generated using the
seed, while on RSA the two primes. To specify an explicit seed
(by default a random seed is used), use the  <code class="code">data</code> with a <code class="code">GNUTLS_KEYGEN_SEED</code> 
type.
</p>
<p>Note that when generating an elliptic curve key, the curve
can be substituted in the place of the bits parameter using the
<code class="code">GNUTLS_CURVE_TO_BITS()</code>  macro.
</p>
<p>To export the generated keys in memory or in files it is recommended to use the
PKCS<code class="code">8</code>  form as it can handle all key types, and can store additional parameters
such as the seed, in case of provable RSA or DSA keys.
Generated keys can be exported in memory using <code class="code">gnutls_privkey_export_x509()</code> ,
and then with <code class="code">gnutls_x509_privkey_export2_pkcs8()</code> .
</p>
<p>If key generation is part of your application, avoid setting the number
of bits directly, and instead use <code class="code">gnutls_sec_param_to_pk_bits()</code> .
That way the generated keys will adapt to the security levels
of the underlying GnuTLS library.
</p>
<p>See also <code class="code">gnutls_privkey_generate2()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fprivkey_005fget_005fkey_005fid-1"><span>gnutls_x509_privkey_get_key_id<a class="copiable-link" href="#gnutls_005fx509_005fprivkey_005fget_005fkey_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fprivkey_005fget_005fkey_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fprivkey_005fget_005fkey_005fid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_privkey_get_key_id</strong> <code class="def-code-arguments">(gnutls_x509_privkey_t <var class="var">key</var>, unsigned int <var class="var">flags</var>, unsigned char * <var class="var">output_data</var>, size_t * <var class="var">output_data_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fprivkey_005fget_005fkey_005fid"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: a key
</p>
<p><var class="var">flags</var>: should be one of the flags from <code class="code">gnutls_keyid_flags_t</code> 
</p>
<p><var class="var">output_data</var>: will contain the key ID
</p>
<p><var class="var">output_data_size</var>: holds the size of output_data (and will be
replaced by the actual size of parameters)
</p>
<p>This function will return a unique ID that depends on the public key
parameters. This ID can be used in checking whether a certificate
corresponds to the given key.
</p>
<p>If the buffer provided is not long enough to hold the output, then
* <code class="code">output_data_size</code> is updated and <code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  will
be returned.  The output will normally be a SHA-1 hash output,
which is 20 bytes.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fprivkey_005fget_005fpk_005falgorithm-1"><span>gnutls_x509_privkey_get_pk_algorithm<a class="copiable-link" href="#gnutls_005fx509_005fprivkey_005fget_005fpk_005falgorithm-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fprivkey_005fget_005fpk_005falgorithm"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fprivkey_005fget_005fpk_005falgorithm"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_privkey_get_pk_algorithm</strong> <code class="def-code-arguments">(gnutls_x509_privkey_t <var class="var">key</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fprivkey_005fget_005fpk_005falgorithm"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: should contain a <code class="code">gnutls_x509_privkey_t</code>  type
</p>
<p>This function will return the public key algorithm of a private
key.
</p>
<p><strong class="strong">Returns:</strong> a member of the <code class="code">gnutls_pk_algorithm_t</code>  enumeration on
success, or a negative error code on error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fprivkey_005fget_005fpk_005falgorithm2-1"><span>gnutls_x509_privkey_get_pk_algorithm2<a class="copiable-link" href="#gnutls_005fx509_005fprivkey_005fget_005fpk_005falgorithm2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fprivkey_005fget_005fpk_005falgorithm2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fprivkey_005fget_005fpk_005falgorithm2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_privkey_get_pk_algorithm2</strong> <code class="def-code-arguments">(gnutls_x509_privkey_t <var class="var">key</var>, unsigned int * <var class="var">bits</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fprivkey_005fget_005fpk_005falgorithm2"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: should contain a <code class="code">gnutls_x509_privkey_t</code>  type
</p>
<p><var class="var">bits</var>: The number of bits in the public key algorithm
</p>
<p>This function will return the public key algorithm of a private
key.
</p>
<p><strong class="strong">Returns:</strong> a member of the <code class="code">gnutls_pk_algorithm_t</code>  enumeration on
success, or a negative error code on error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fprivkey_005fget_005fseed-1"><span>gnutls_x509_privkey_get_seed<a class="copiable-link" href="#gnutls_005fx509_005fprivkey_005fget_005fseed-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fprivkey_005fget_005fseed"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fprivkey_005fget_005fseed"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_privkey_get_seed</strong> <code class="def-code-arguments">(gnutls_x509_privkey_t <var class="var">key</var>, gnutls_digest_algorithm_t * <var class="var">digest</var>, void * <var class="var">seed</var>, size_t * <var class="var">seed_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fprivkey_005fget_005fseed"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: should contain a <code class="code">gnutls_x509_privkey_t</code>  type
</p>
<p><var class="var">digest</var>: if non-NULL it will contain the digest algorithm used for key generation (if applicable)
</p>
<p><var class="var">seed</var>: where seed will be copied to
</p>
<p><var class="var">seed_size</var>: originally holds the size of  <code class="code">seed</code> , will be updated with actual size
</p>
<p>This function will return the seed that was used to generate the
given private key. That function will succeed only if the key was generated
as a provable key.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.5.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fprivkey_005fget_005fspki-1"><span>gnutls_x509_privkey_get_spki<a class="copiable-link" href="#gnutls_005fx509_005fprivkey_005fget_005fspki-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fprivkey_005fget_005fspki"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fprivkey_005fget_005fspki"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_privkey_get_spki</strong> <code class="def-code-arguments">(gnutls_x509_privkey_t <var class="var">key</var>, gnutls_x509_spki_t <var class="var">spki</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fprivkey_005fget_005fspki"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: should contain a <code class="code">gnutls_x509_privkey_t</code>  type
</p>
<p><var class="var">spki</var>: a SubjectPublicKeyInfo structure of type <code class="code">gnutls_x509_spki_t</code> 
</p>
<p><var class="var">flags</var>: must be zero
</p>
<p>This function will return the public key information of a private
key. The provided  <code class="code">spki</code> must be initialized.
</p>
<p><strong class="strong">Returns:</strong> Zero on success, or a negative error code on error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fprivkey_005fimport-1"><span>gnutls_x509_privkey_import<a class="copiable-link" href="#gnutls_005fx509_005fprivkey_005fimport-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fprivkey_005fimport"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fprivkey_005fimport"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_privkey_import</strong> <code class="def-code-arguments">(gnutls_x509_privkey_t <var class="var">key</var>, const gnutls_datum_t * <var class="var">data</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fprivkey_005fimport"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: The data to store the parsed key
</p>
<p><var class="var">data</var>: The DER or PEM encoded certificate.
</p>
<p><var class="var">format</var>: One of DER or PEM
</p>
<p>This function will convert the given DER or PEM encoded key to the
native <code class="code">gnutls_x509_privkey_t</code>  format. The output will be stored in
 <code class="code">key</code> .
</p>
<p>If the key is PEM encoded it should have a header that contains &quot;PRIVATE
KEY&quot;. Note that this function falls back to PKCS <code class="code">8</code>  decoding without
password, if the default format fails to import.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fprivkey_005fimport2-1"><span>gnutls_x509_privkey_import2<a class="copiable-link" href="#gnutls_005fx509_005fprivkey_005fimport2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fprivkey_005fimport2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fprivkey_005fimport2-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_privkey_import2</strong> <code class="def-code-arguments">(gnutls_x509_privkey_t <var class="var">key</var>, const gnutls_datum_t * <var class="var">data</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, const char * <var class="var">password</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fprivkey_005fimport2-1"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: The data to store the parsed key
</p>
<p><var class="var">data</var>: The DER or PEM encoded key.
</p>
<p><var class="var">format</var>: One of DER or PEM
</p>
<p><var class="var">password</var>: A password (optional)
</p>
<p><var class="var">flags</var>: an ORed sequence of gnutls_pkcs_encrypt_flags_t
</p>
<p>This function will import the given DER or PEM encoded key, to 
the native <code class="code">gnutls_x509_privkey_t</code>  format, irrespective of the
input format. The input format is auto-detected.
</p>
<p>The supported formats are basic unencrypted key, PKCS8, PKCS12,
and the openssl format.
</p>
<p>If the provided key is encrypted but no password was given, then
<code class="code">GNUTLS_E_DECRYPTION_FAILED</code>  is returned. Since GnuTLS 3.4.0 this
function will utilize the PIN callbacks if any.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fprivkey_005fimport_005fdh_005fraw-1"><span>gnutls_x509_privkey_import_dh_raw<a class="copiable-link" href="#gnutls_005fx509_005fprivkey_005fimport_005fdh_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fprivkey_005fimport_005fdh_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fprivkey_005fimport_005fdh_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_privkey_import_dh_raw</strong> <code class="def-code-arguments">(gnutls_x509_privkey_t <var class="var">key</var>, const gnutls_dh_params_t <var class="var">params</var>, const gnutls_datum_t * <var class="var">y</var>, const gnutls_datum_t * <var class="var">x</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fprivkey_005fimport_005fdh_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: The data to store the parsed key
</p>
<p><var class="var">params</var>: holds the <code class="code">gnutls_dh_params_t</code> 
</p>
<p><var class="var">y</var>: holds the y (optional)
</p>
<p><var class="var">x</var>: holds the x
</p>
<p>This function will convert the given Diffie-Hellman raw parameters
to the native <code class="code">gnutls_x509_privkey_t</code>  format.  The output will be
stored in  <code class="code">key</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fprivkey_005fimport_005fdsa_005fraw-1"><span>gnutls_x509_privkey_import_dsa_raw<a class="copiable-link" href="#gnutls_005fx509_005fprivkey_005fimport_005fdsa_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fprivkey_005fimport_005fdsa_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fprivkey_005fimport_005fdsa_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_privkey_import_dsa_raw</strong> <code class="def-code-arguments">(gnutls_x509_privkey_t <var class="var">key</var>, const gnutls_datum_t * <var class="var">p</var>, const gnutls_datum_t * <var class="var">q</var>, const gnutls_datum_t * <var class="var">g</var>, const gnutls_datum_t * <var class="var">y</var>, const gnutls_datum_t * <var class="var">x</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fprivkey_005fimport_005fdsa_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: The data to store the parsed key
</p>
<p><var class="var">p</var>: holds the p
</p>
<p><var class="var">q</var>: holds the q
</p>
<p><var class="var">g</var>: holds the g
</p>
<p><var class="var">y</var>: holds the y (optional)
</p>
<p><var class="var">x</var>: holds the x
</p>
<p>This function will convert the given DSA raw parameters to the
native <code class="code">gnutls_x509_privkey_t</code>  format.  The output will be stored
in  <code class="code">key</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fprivkey_005fimport_005fecc_005fraw-1"><span>gnutls_x509_privkey_import_ecc_raw<a class="copiable-link" href="#gnutls_005fx509_005fprivkey_005fimport_005fecc_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fprivkey_005fimport_005fecc_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fprivkey_005fimport_005fecc_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_privkey_import_ecc_raw</strong> <code class="def-code-arguments">(gnutls_x509_privkey_t <var class="var">key</var>, gnutls_ecc_curve_t <var class="var">curve</var>, const gnutls_datum_t * <var class="var">x</var>, const gnutls_datum_t * <var class="var">y</var>, const gnutls_datum_t * <var class="var">k</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fprivkey_005fimport_005fecc_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: The data to store the parsed key
</p>
<p><var class="var">curve</var>: holds the curve
</p>
<p><var class="var">x</var>: holds the x-coordinate
</p>
<p><var class="var">y</var>: holds the y-coordinate
</p>
<p><var class="var">k</var>: holds the k
</p>
<p>This function will convert the given elliptic curve parameters to the
native <code class="code">gnutls_x509_privkey_t</code>  format.  The output will be stored
in  <code class="code">key</code> . For EdDSA keys, the  <code class="code">x</code> and  <code class="code">k</code> values must be in the
native to curve format.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fprivkey_005fimport_005fgost_005fraw-1"><span>gnutls_x509_privkey_import_gost_raw<a class="copiable-link" href="#gnutls_005fx509_005fprivkey_005fimport_005fgost_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fprivkey_005fimport_005fgost_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fprivkey_005fimport_005fgost_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_privkey_import_gost_raw</strong> <code class="def-code-arguments">(gnutls_x509_privkey_t <var class="var">key</var>, gnutls_ecc_curve_t <var class="var">curve</var>, gnutls_digest_algorithm_t <var class="var">digest</var>, gnutls_gost_paramset_t <var class="var">paramset</var>, const gnutls_datum_t * <var class="var">x</var>, const gnutls_datum_t * <var class="var">y</var>, const gnutls_datum_t * <var class="var">k</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fprivkey_005fimport_005fgost_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: The data to store the parsed key
</p>
<p><var class="var">curve</var>: holds the curve
</p>
<p><var class="var">digest</var>: will hold the digest
</p>
<p><var class="var">paramset</var>: will hold the GOST parameter set ID
</p>
<p><var class="var">x</var>: holds the x-coordinate
</p>
<p><var class="var">y</var>: holds the y-coordinate
</p>
<p><var class="var">k</var>: holds the k (private key)
</p>
<p>This function will convert the given GOST private key&rsquo;s parameters to the
native <code class="code">gnutls_x509_privkey_t</code>  format.  The output will be stored
in  <code class="code">key</code> .   <code class="code">digest</code> should be one of GNUTLS_DIG_GOSR_94,
GNUTLS_DIG_STREEBOG_256 or GNUTLS_DIG_STREEBOG_512.  If  <code class="code">paramset</code> is set to
GNUTLS_GOST_PARAMSET_UNKNOWN default one will be selected depending on
 <code class="code">digest</code> .
</p>
<p><strong class="strong">Note:</strong> parameters should be stored with least significant byte first. On
version 3.6.3 big-endian format was used incorrectly.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.6.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fprivkey_005fimport_005fopenssl-1"><span>gnutls_x509_privkey_import_openssl<a class="copiable-link" href="#gnutls_005fx509_005fprivkey_005fimport_005fopenssl-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fprivkey_005fimport_005fopenssl"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fprivkey_005fimport_005fopenssl-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_privkey_import_openssl</strong> <code class="def-code-arguments">(gnutls_x509_privkey_t <var class="var">key</var>, const gnutls_datum_t * <var class="var">data</var>, const char * <var class="var">password</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fprivkey_005fimport_005fopenssl-1"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: The data to store the parsed key
</p>
<p><var class="var">data</var>: The DER or PEM encoded key.
</p>
<p><var class="var">password</var>: the password to decrypt the key (if it is encrypted).
</p>
<p>This function will convert the given PEM encrypted to 
the native gnutls_x509_privkey_t format. The
output will be stored in  <code class="code">key</code> .  
</p>
<p>The  <code class="code">password</code> should be in ASCII. If the password is not provided
or wrong then <code class="code">GNUTLS_E_DECRYPTION_FAILED</code>  will be returned.
</p>
<p>If the Certificate is PEM encoded it should have a header of
&quot;PRIVATE KEY&quot; and the &quot;DEK-Info&quot; header. 
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fprivkey_005fimport_005fpkcs8-1"><span>gnutls_x509_privkey_import_pkcs8<a class="copiable-link" href="#gnutls_005fx509_005fprivkey_005fimport_005fpkcs8-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fprivkey_005fimport_005fpkcs8"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fprivkey_005fimport_005fpkcs8"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_privkey_import_pkcs8</strong> <code class="def-code-arguments">(gnutls_x509_privkey_t <var class="var">key</var>, const gnutls_datum_t * <var class="var">data</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, const char * <var class="var">password</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fprivkey_005fimport_005fpkcs8"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: The data to store the parsed key
</p>
<p><var class="var">data</var>: The DER or PEM encoded key.
</p>
<p><var class="var">format</var>: One of DER or PEM
</p>
<p><var class="var">password</var>: the password to decrypt the key (if it is encrypted).
</p>
<p><var class="var">flags</var>: 0 if encrypted or GNUTLS_PKCS_PLAIN if not encrypted.
</p>
<p>This function will convert the given DER or PEM encoded PKCS8 2.0
encrypted key to the native gnutls_x509_privkey_t format. The
output will be stored in  <code class="code">key</code> .  Both RSA and DSA keys can be
imported, and flags can only be used to indicate an unencrypted
key.
</p>
<p>The  <code class="code">password</code> can be either ASCII or UTF-8 in the default PBES2
encryption schemas, or ASCII for the PKCS12 schemas.
</p>
<p>If the Certificate is PEM encoded it should have a header of
&quot;ENCRYPTED PRIVATE KEY&quot;, or &quot;PRIVATE KEY&quot;. You only need to
specify the flags if the key is DER encoded, since in that case
the encryption status cannot be auto-detected.
</p>
<p>If the <code class="code">GNUTLS_PKCS_PLAIN</code>  flag is specified and the supplied data
are encrypted then <code class="code">GNUTLS_E_DECRYPTION_FAILED</code>  is returned.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fprivkey_005fimport_005frsa_005fraw-1"><span>gnutls_x509_privkey_import_rsa_raw<a class="copiable-link" href="#gnutls_005fx509_005fprivkey_005fimport_005frsa_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fprivkey_005fimport_005frsa_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fprivkey_005fimport_005frsa_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_privkey_import_rsa_raw</strong> <code class="def-code-arguments">(gnutls_x509_privkey_t <var class="var">key</var>, const gnutls_datum_t * <var class="var">m</var>, const gnutls_datum_t * <var class="var">e</var>, const gnutls_datum_t * <var class="var">d</var>, const gnutls_datum_t * <var class="var">p</var>, const gnutls_datum_t * <var class="var">q</var>, const gnutls_datum_t * <var class="var">u</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fprivkey_005fimport_005frsa_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: The data to store the parsed key
</p>
<p><var class="var">m</var>: holds the modulus
</p>
<p><var class="var">e</var>: holds the public exponent
</p>
<p><var class="var">d</var>: holds the private exponent
</p>
<p><var class="var">p</var>: holds the first prime (p)
</p>
<p><var class="var">q</var>: holds the second prime (q)
</p>
<p><var class="var">u</var>: holds the coefficient
</p>
<p>This function will convert the given RSA raw parameters to the
native <code class="code">gnutls_x509_privkey_t</code>  format.  The output will be stored in
 <code class="code">key</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fprivkey_005fimport_005frsa_005fraw2-1"><span>gnutls_x509_privkey_import_rsa_raw2<a class="copiable-link" href="#gnutls_005fx509_005fprivkey_005fimport_005frsa_005fraw2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fprivkey_005fimport_005frsa_005fraw2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fprivkey_005fimport_005frsa_005fraw2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_privkey_import_rsa_raw2</strong> <code class="def-code-arguments">(gnutls_x509_privkey_t <var class="var">key</var>, const gnutls_datum_t * <var class="var">m</var>, const gnutls_datum_t * <var class="var">e</var>, const gnutls_datum_t * <var class="var">d</var>, const gnutls_datum_t * <var class="var">p</var>, const gnutls_datum_t * <var class="var">q</var>, const gnutls_datum_t * <var class="var">u</var>, const gnutls_datum_t * <var class="var">e1</var>, const gnutls_datum_t * <var class="var">e2</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fprivkey_005fimport_005frsa_005fraw2"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: The data to store the parsed key
</p>
<p><var class="var">m</var>: holds the modulus
</p>
<p><var class="var">e</var>: holds the public exponent
</p>
<p><var class="var">d</var>: holds the private exponent
</p>
<p><var class="var">p</var>: holds the first prime (p)
</p>
<p><var class="var">q</var>: holds the second prime (q)
</p>
<p><var class="var">u</var>: holds the coefficient (optional)
</p>
<p><var class="var">e1</var>: holds e1 = d mod (p-1) (optional)
</p>
<p><var class="var">e2</var>: holds e2 = d mod (q-1) (optional)
</p>
<p>This function will convert the given RSA raw parameters to the
native <code class="code">gnutls_x509_privkey_t</code>  format.  The output will be stored in
 <code class="code">key</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fprivkey_005finit-1"><span>gnutls_x509_privkey_init<a class="copiable-link" href="#gnutls_005fx509_005fprivkey_005finit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fprivkey_005finit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fprivkey_005finit"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_privkey_init</strong> <code class="def-code-arguments">(gnutls_x509_privkey_t * <var class="var">key</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fprivkey_005finit"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: A pointer to the type to be initialized
</p>
<p>This function will initialize a private key type.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fprivkey_005fsec_005fparam-1"><span>gnutls_x509_privkey_sec_param<a class="copiable-link" href="#gnutls_005fx509_005fprivkey_005fsec_005fparam-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fprivkey_005fsec_005fparam"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fprivkey_005fsec_005fparam"><span class="category-def">Function: </span><span><code class="def-type">gnutls_sec_param_t</code> <strong class="def-name">gnutls_x509_privkey_sec_param</strong> <code class="def-code-arguments">(gnutls_x509_privkey_t <var class="var">key</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fprivkey_005fsec_005fparam"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: a key
</p>
<p>This function will return the security parameter appropriate with
this private key.
</p>
<p><strong class="strong">Returns:</strong> On success, a valid security parameter is returned otherwise
<code class="code">GNUTLS_SEC_PARAM_UNKNOWN</code>  is returned.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fprivkey_005fset_005fflags-1"><span>gnutls_x509_privkey_set_flags<a class="copiable-link" href="#gnutls_005fx509_005fprivkey_005fset_005fflags-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fprivkey_005fset_005fflags"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fprivkey_005fset_005fflags"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_x509_privkey_set_flags</strong> <code class="def-code-arguments">(gnutls_x509_privkey_t <var class="var">key</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fprivkey_005fset_005fflags"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: A key of type <code class="code">gnutls_x509_privkey_t</code> 
</p>
<p><var class="var">flags</var>: flags from the <code class="code">gnutls_privkey_flags</code> 
</p>
<p>This function will set flags for the specified private key, after
it is generated. Currently this is useful for the <code class="code">GNUTLS_PRIVKEY_FLAG_EXPORT_COMPAT</code> 
to allow exporting a &quot;provable&quot; private key in backwards compatible way.
</p>
<p><strong class="strong">Since:</strong> 3.5.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fprivkey_005fset_005fpin_005ffunction-1"><span>gnutls_x509_privkey_set_pin_function<a class="copiable-link" href="#gnutls_005fx509_005fprivkey_005fset_005fpin_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fprivkey_005fset_005fpin_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fprivkey_005fset_005fpin_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_x509_privkey_set_pin_function</strong> <code class="def-code-arguments">(gnutls_x509_privkey_t <var class="var">privkey</var>, gnutls_pin_callback_t <var class="var">fn</var>, void * <var class="var">userdata</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fprivkey_005fset_005fpin_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">privkey</var>: The certificate structure
</p>
<p><var class="var">fn</var>: the callback
</p>
<p><var class="var">userdata</var>: data associated with the callback
</p>
<p>This function will set a callback function to be used when
it is required to access a protected object. This function overrides 
the global function set using <code class="code">gnutls_pkcs11_set_pin_function()</code> .
</p>
<p>Note that this callback is used when decrypting a key.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fprivkey_005fset_005fspki-1"><span>gnutls_x509_privkey_set_spki<a class="copiable-link" href="#gnutls_005fx509_005fprivkey_005fset_005fspki-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fprivkey_005fset_005fspki"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fprivkey_005fset_005fspki"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_privkey_set_spki</strong> <code class="def-code-arguments">(gnutls_x509_privkey_t <var class="var">key</var>, const gnutls_x509_spki_t <var class="var">spki</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fprivkey_005fset_005fspki"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: should contain a <code class="code">gnutls_x509_privkey_t</code>  type
</p>
<p><var class="var">spki</var>: a SubjectPublicKeyInfo structure of type <code class="code">gnutls_x509_spki_t</code> 
</p>
<p><var class="var">flags</var>: must be zero
</p>
<p>This function will return the public key information of a private
key. The provided  <code class="code">spki</code> must be initialized.
</p>
<p><strong class="strong">Returns:</strong> Zero on success, or a negative error code on error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fprivkey_005fsign_005fdata-1"><span>gnutls_x509_privkey_sign_data<a class="copiable-link" href="#gnutls_005fx509_005fprivkey_005fsign_005fdata-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fprivkey_005fsign_005fdata"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fprivkey_005fsign_005fdata"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_privkey_sign_data</strong> <code class="def-code-arguments">(gnutls_x509_privkey_t <var class="var">key</var>, gnutls_digest_algorithm_t <var class="var">digest</var>, unsigned int <var class="var">flags</var>, const gnutls_datum_t * <var class="var">data</var>, void * <var class="var">signature</var>, size_t * <var class="var">signature_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fprivkey_005fsign_005fdata"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: a key
</p>
<p><var class="var">digest</var>: should be a digest algorithm
</p>
<p><var class="var">flags</var>: should be 0 for now
</p>
<p><var class="var">data</var>: holds the data to be signed
</p>
<p><var class="var">signature</var>: will contain the signature
</p>
<p><var class="var">signature_size</var>: holds the size of signature (and will be replaced
by the new size)
</p>
<p>This function will sign the given data using a signature algorithm
supported by the private key. Signature algorithms are always used
together with a hash functions.  Different hash functions may be
used for the RSA algorithm, but only SHA-1 for the DSA keys.
</p>
<p>If the buffer provided is not long enough to hold the output, then
* <code class="code">signature_size</code> is updated and <code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  will
be returned.
</p>
<p>Use <code class="code">gnutls_x509_crt_get_preferred_hash_algorithm()</code>  to determine
the hash algorithm.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fprivkey_005fverify_005fparams-1"><span>gnutls_x509_privkey_verify_params<a class="copiable-link" href="#gnutls_005fx509_005fprivkey_005fverify_005fparams-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fprivkey_005fverify_005fparams"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fprivkey_005fverify_005fparams"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_privkey_verify_params</strong> <code class="def-code-arguments">(gnutls_x509_privkey_t <var class="var">key</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fprivkey_005fverify_005fparams"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: a key
</p>
<p>This function will verify the private key parameters.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fprivkey_005fverify_005fseed-1"><span>gnutls_x509_privkey_verify_seed<a class="copiable-link" href="#gnutls_005fx509_005fprivkey_005fverify_005fseed-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fprivkey_005fverify_005fseed"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fprivkey_005fverify_005fseed"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_privkey_verify_seed</strong> <code class="def-code-arguments">(gnutls_x509_privkey_t <var class="var">key</var>, gnutls_digest_algorithm_t <var class="var">digest</var>, const void * <var class="var">seed</var>, size_t <var class="var">seed_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fprivkey_005fverify_005fseed"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: should contain a <code class="code">gnutls_x509_privkey_t</code>  type
</p>
<p><var class="var">digest</var>: it contains the digest algorithm used for key generation (if applicable)
</p>
<p><var class="var">seed</var>: the seed of the key to be checked with
</p>
<p><var class="var">seed_size</var>: holds the size of  <code class="code">seed</code> 
</p>
<p>This function will verify that the given private key was generated from
the provided seed. If  <code class="code">seed</code> is <code class="code">NULL</code>  then the seed stored in the  <code class="code">key</code> &rsquo;s structure
will be used for verification.
</p>
<p><strong class="strong">Returns:</strong> In case of a verification failure <code class="code">GNUTLS_E_PRIVKEY_VERIFICATION_ERROR</code> 
is returned, and zero or positive code on success.
</p>
<p><strong class="strong">Since:</strong> 3.5.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005frdn_005fget-1"><span>gnutls_x509_rdn_get<a class="copiable-link" href="#gnutls_005fx509_005frdn_005fget-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005frdn_005fget"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005frdn_005fget"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_rdn_get</strong> <code class="def-code-arguments">(const gnutls_datum_t * <var class="var">idn</var>, char * <var class="var">buf</var>, size_t * <var class="var">buf_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005frdn_005fget"> &para;</a></span></dt>
<dd><p><var class="var">idn</var>: should contain a DER encoded RDN sequence
</p>
<p><var class="var">buf</var>: a pointer to a structure to hold the peer&rsquo;s name
</p>
<p><var class="var">buf_size</var>: holds the size of  <code class="code">buf</code> 
</p>
<p>This function will return the name of the given RDN sequence.  The
name will be in the form &quot;C=xxxx,O=yyyy,CN=zzzz&quot; as described in
RFC4514.
</p>
<p>This function does not output a fully RFC4514 compliant string, if
that is required see <code class="code">gnutls_x509_rdn_get2()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, or
<code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  is returned and * <code class="code">buf_size</code> is
updated if the provided buffer is not long enough, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005frdn_005fget2-1"><span>gnutls_x509_rdn_get2<a class="copiable-link" href="#gnutls_005fx509_005frdn_005fget2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005frdn_005fget2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005frdn_005fget2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_rdn_get2</strong> <code class="def-code-arguments">(const gnutls_datum_t * <var class="var">idn</var>, gnutls_datum_t * <var class="var">str</var>, unsigned <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005frdn_005fget2"> &para;</a></span></dt>
<dd><p><var class="var">idn</var>: should contain a DER encoded RDN sequence
</p>
<p><var class="var">str</var>: a datum that will hold the name
</p>
<p><var class="var">flags</var>: zero of <code class="code">GNUTLS_X509_DN_FLAG_COMPAT</code> 
</p>
<p>This function will return the name of the given RDN sequence.  The
name will be in the form &quot;C=xxxx,O=yyyy,CN=zzzz&quot; as described in
RFC4514.
</p>
<p>When the flag <code class="code">GNUTLS_X509_DN_FLAG_COMPAT</code>  is specified, the output
format will match the format output by previous to 3.5.6 versions of GnuTLS
which was not not fully RFC4514-compliant.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, or
<code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  is returned and * <code class="code">buf_size</code> is
updated if the provided buffer is not long enough, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005frdn_005fget_005fby_005foid-1"><span>gnutls_x509_rdn_get_by_oid<a class="copiable-link" href="#gnutls_005fx509_005frdn_005fget_005fby_005foid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005frdn_005fget_005fby_005foid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005frdn_005fget_005fby_005foid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_rdn_get_by_oid</strong> <code class="def-code-arguments">(const gnutls_datum_t * <var class="var">idn</var>, const char * <var class="var">oid</var>, unsigned <var class="var">indx</var>, unsigned int <var class="var">raw_flag</var>, void * <var class="var">buf</var>, size_t * <var class="var">buf_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005frdn_005fget_005fby_005foid"> &para;</a></span></dt>
<dd><p><var class="var">idn</var>: should contain a DER encoded RDN sequence
</p>
<p><var class="var">oid</var>: an Object Identifier
</p>
<p><var class="var">indx</var>: In case multiple same OIDs exist in the RDN indicates which
to send. Use 0 for the first one.
</p>
<p><var class="var">raw_flag</var>: If non-zero then the raw DER data are returned.
</p>
<p><var class="var">buf</var>: a pointer to a structure to hold the peer&rsquo;s name
</p>
<p><var class="var">buf_size</var>: holds the size of  <code class="code">buf</code> 
</p>
<p>This function will return the name of the given Object identifier,
of the RDN sequence.  The name will be encoded using the rules
from RFC4514.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, or
<code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  is returned and * <code class="code">buf_size</code> is
updated if the provided buffer is not long enough, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005frdn_005fget_005foid-1"><span>gnutls_x509_rdn_get_oid<a class="copiable-link" href="#gnutls_005fx509_005frdn_005fget_005foid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005frdn_005fget_005foid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005frdn_005fget_005foid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_rdn_get_oid</strong> <code class="def-code-arguments">(const gnutls_datum_t * <var class="var">idn</var>, unsigned <var class="var">indx</var>, void * <var class="var">buf</var>, size_t * <var class="var">buf_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005frdn_005fget_005foid"> &para;</a></span></dt>
<dd><p><var class="var">idn</var>: should contain a DER encoded RDN sequence
</p>
<p><var class="var">indx</var>: Indicates which OID to return. Use 0 for the first one.
</p>
<p><var class="var">buf</var>: a pointer to a structure to hold the peer&rsquo;s name OID
</p>
<p><var class="var">buf_size</var>: holds the size of  <code class="code">buf</code> 
</p>
<p>This function will return the specified Object identifier, of the
RDN sequence.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, or
<code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  is returned and * <code class="code">buf_size</code> is
updated if the provided buffer is not long enough, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fspki_005fdeinit-1"><span>gnutls_x509_spki_deinit<a class="copiable-link" href="#gnutls_005fx509_005fspki_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fspki_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fspki_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_x509_spki_deinit</strong> <code class="def-code-arguments">(gnutls_x509_spki_t <var class="var">spki</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fspki_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">spki</var>: the SubjectPublicKeyInfo structure
</p>
<p>This function will deinitialize a SubjectPublicKeyInfo structure.
</p>
<p><strong class="strong">Since:</strong> 3.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fspki_005fget_005frsa_005foaep_005fparams-1"><span>gnutls_x509_spki_get_rsa_oaep_params<a class="copiable-link" href="#gnutls_005fx509_005fspki_005fget_005frsa_005foaep_005fparams-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fspki_005fget_005frsa_005foaep_005fparams"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fspki_005fget_005frsa_005foaep_005fparams"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_spki_get_rsa_oaep_params</strong> <code class="def-code-arguments">(gnutls_x509_spki_t <var class="var">spki</var>, gnutls_digest_algorithm_t * <var class="var">dig</var>, gnutls_datum_t * <var class="var">label</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fspki_005fget_005frsa_005foaep_005fparams"> &para;</a></span></dt>
<dd><p><var class="var">spki</var>: the SubjectPublicKeyInfo structure
</p>
<p><var class="var">dig</var>: if non-NULL, it will hold the digest algorithm
</p>
<p><var class="var">label</var>: if non-NULL, it will hold the pointer to label
</p>
<p>This function will get the public key algorithm parameters
of RSA-OAEP type.
</p>
<p><strong class="strong">Returns:</strong> zero if the parameters are present or a negative
value on error.
</p>
<p><strong class="strong">Since:</strong> 3.8.4
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fspki_005fget_005frsa_005fpss_005fparams-1"><span>gnutls_x509_spki_get_rsa_pss_params<a class="copiable-link" href="#gnutls_005fx509_005fspki_005fget_005frsa_005fpss_005fparams-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fspki_005fget_005frsa_005fpss_005fparams"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fspki_005fget_005frsa_005fpss_005fparams"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_spki_get_rsa_pss_params</strong> <code class="def-code-arguments">(gnutls_x509_spki_t <var class="var">spki</var>, gnutls_digest_algorithm_t * <var class="var">dig</var>, unsigned int * <var class="var">salt_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fspki_005fget_005frsa_005fpss_005fparams"> &para;</a></span></dt>
<dd><p><var class="var">spki</var>: the SubjectPublicKeyInfo structure
</p>
<p><var class="var">dig</var>: if non-NULL, it will hold the digest algorithm
</p>
<p><var class="var">salt_size</var>: if non-NULL, it will hold the salt size
</p>
<p>This function will get the public key algorithm parameters
of RSA-PSS type.
</p>
<p><strong class="strong">Returns:</strong> zero if the parameters are present or a negative
value on error.
</p>
<p><strong class="strong">Since:</strong> 3.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fspki_005finit-1"><span>gnutls_x509_spki_init<a class="copiable-link" href="#gnutls_005fx509_005fspki_005finit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fspki_005finit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fspki_005finit"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_spki_init</strong> <code class="def-code-arguments">(gnutls_x509_spki_t * <var class="var">spki</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fspki_005finit"> &para;</a></span></dt>
<dd><p><var class="var">spki</var>: A pointer to the type to be initialized
</p>
<p>This function will initialize a SubjectPublicKeyInfo structure used
in PKIX. The structure is used to set additional parameters
in the public key information field of a certificate.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fspki_005fset_005frsa_005foaep_005fparams-1"><span>gnutls_x509_spki_set_rsa_oaep_params<a class="copiable-link" href="#gnutls_005fx509_005fspki_005fset_005frsa_005foaep_005fparams-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fspki_005fset_005frsa_005foaep_005fparams"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fspki_005fset_005frsa_005foaep_005fparams"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_spki_set_rsa_oaep_params</strong> <code class="def-code-arguments">(gnutls_x509_spki_t <var class="var">spki</var>, gnutls_digest_algorithm_t <var class="var">dig</var>, const gnutls_datum_t * <var class="var">label</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fspki_005fset_005frsa_005foaep_005fparams"> &para;</a></span></dt>
<dd><p><var class="var">spki</var>: the SubjectPublicKeyInfo structure
</p>
<p><var class="var">dig</var>: a digest algorithm of type <code class="code">gnutls_digest_algorithm_t</code> 
</p>
<p><var class="var">label</var>: optional label
</p>
<p>This function will set the public key parameters for
an RSA-OAEP algorithm, in the SubjectPublicKeyInfo structure.
</p>
<p><strong class="strong">Returns:</strong> zero if the parameters are present or a negative
value on error.
</p>
<p><strong class="strong">Since:</strong> 3.8.4
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fspki_005fset_005frsa_005fpss_005fparams-1"><span>gnutls_x509_spki_set_rsa_pss_params<a class="copiable-link" href="#gnutls_005fx509_005fspki_005fset_005frsa_005fpss_005fparams-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fspki_005fset_005frsa_005fpss_005fparams"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fspki_005fset_005frsa_005fpss_005fparams"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_x509_spki_set_rsa_pss_params</strong> <code class="def-code-arguments">(gnutls_x509_spki_t <var class="var">spki</var>, gnutls_digest_algorithm_t <var class="var">dig</var>, unsigned int <var class="var">salt_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fspki_005fset_005frsa_005fpss_005fparams"> &para;</a></span></dt>
<dd><p><var class="var">spki</var>: the SubjectPublicKeyInfo structure
</p>
<p><var class="var">dig</var>: a digest algorithm of type <code class="code">gnutls_digest_algorithm_t</code> 
</p>
<p><var class="var">salt_size</var>: the size of salt string
</p>
<p>This function will set the public key parameters for
an RSA-PSS algorithm, in the SubjectPublicKeyInfo structure.
</p>
<p><strong class="strong">Since:</strong> 3.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005ftlsfeatures_005fadd-1"><span>gnutls_x509_tlsfeatures_add<a class="copiable-link" href="#gnutls_005fx509_005ftlsfeatures_005fadd-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005ftlsfeatures_005fadd"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005ftlsfeatures_005fadd"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_tlsfeatures_add</strong> <code class="def-code-arguments">(gnutls_x509_tlsfeatures_t <var class="var">f</var>, unsigned int <var class="var">feature</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005ftlsfeatures_005fadd"> &para;</a></span></dt>
<dd><p><var class="var">f</var>: The TLS features
</p>
<p><var class="var">feature</var>: The feature to add
</p>
<p>This function will append a feature to the X.509 TLS features
extension structure.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.5.1
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005ftlsfeatures_005fcheck_005fcrt-1"><span>gnutls_x509_tlsfeatures_check_crt<a class="copiable-link" href="#gnutls_005fx509_005ftlsfeatures_005fcheck_005fcrt-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005ftlsfeatures_005fcheck_005fcrt"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005ftlsfeatures_005fcheck_005fcrt"><span class="category-def">Function: </span><span><code class="def-type">unsigned</code> <strong class="def-name">gnutls_x509_tlsfeatures_check_crt</strong> <code class="def-code-arguments">(gnutls_x509_tlsfeatures_t <var class="var">feat</var>, gnutls_x509_crt_t <var class="var">cert</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005ftlsfeatures_005fcheck_005fcrt"> &para;</a></span></dt>
<dd><p><var class="var">feat</var>: a set of TLSFeatures
</p>
<p><var class="var">cert</var>: the certificate to be checked
</p>
<p>This function will check the provided certificate against the TLSFeatures
set in  <code class="code">feat</code> using the RFC7633 p.4.2.2 rules. It will check whether the certificate
contains the features in  <code class="code">feat</code> or a superset.
</p>
<p><strong class="strong">Returns:</strong> non-zero if the provided certificate complies, and zero otherwise.
</p>
<p><strong class="strong">Since:</strong> 3.5.1
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005ftlsfeatures_005fdeinit-1"><span>gnutls_x509_tlsfeatures_deinit<a class="copiable-link" href="#gnutls_005fx509_005ftlsfeatures_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005ftlsfeatures_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005ftlsfeatures_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_x509_tlsfeatures_deinit</strong> <code class="def-code-arguments">(gnutls_x509_tlsfeatures_t <var class="var">f</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005ftlsfeatures_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">f</var>: The TLS features
</p>
<p>This function will deinitialize a X.509 TLS features extension structure
</p>
<p><strong class="strong">Since:</strong> 3.5.1
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005ftlsfeatures_005fget-1"><span>gnutls_x509_tlsfeatures_get<a class="copiable-link" href="#gnutls_005fx509_005ftlsfeatures_005fget-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005ftlsfeatures_005fget"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005ftlsfeatures_005fget"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_tlsfeatures_get</strong> <code class="def-code-arguments">(gnutls_x509_tlsfeatures_t <var class="var">f</var>, unsigned <var class="var">idx</var>, unsigned int * <var class="var">feature</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005ftlsfeatures_005fget"> &para;</a></span></dt>
<dd><p><var class="var">f</var>: The TLS features
</p>
<p><var class="var">idx</var>: The index of the feature to get
</p>
<p><var class="var">feature</var>: If the function succeeds, the feature will be stored in this variable
</p>
<p>This function will get a feature from the X.509 TLS features
extension structure.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.5.1
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005ftlsfeatures_005finit-1"><span>gnutls_x509_tlsfeatures_init<a class="copiable-link" href="#gnutls_005fx509_005ftlsfeatures_005finit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005ftlsfeatures_005finit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005ftlsfeatures_005finit"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_tlsfeatures_init</strong> <code class="def-code-arguments">(gnutls_x509_tlsfeatures_t * <var class="var">f</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005ftlsfeatures_005finit"> &para;</a></span></dt>
<dd><p><var class="var">f</var>: The TLS features
</p>
<p>This function will initialize a X.509 TLS features extension structure
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.5.1
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005ftrust_005flist_005fadd_005fcas-1"><span>gnutls_x509_trust_list_add_cas<a class="copiable-link" href="#gnutls_005fx509_005ftrust_005flist_005fadd_005fcas-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005ftrust_005flist_005fadd_005fcas"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005ftrust_005flist_005fadd_005fcas-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_trust_list_add_cas</strong> <code class="def-code-arguments">(gnutls_x509_trust_list_t <var class="var">list</var>, const gnutls_x509_crt_t * <var class="var">clist</var>, unsigned <var class="var">clist_size</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005ftrust_005flist_005fadd_005fcas-1"> &para;</a></span></dt>
<dd><p><var class="var">list</var>: The list
</p>
<p><var class="var">clist</var>: A list of CAs
</p>
<p><var class="var">clist_size</var>: The length of the CA list
</p>
<p><var class="var">flags</var>: flags from <code class="code">gnutls_trust_list_flags_t</code> 
</p>
<p>This function will add the given certificate authorities
to the trusted list. The CAs in  <code class="code">clist</code> must not be deinitialized
during the lifetime of  <code class="code">list</code> .
</p>
<p>If the flag <code class="code">GNUTLS_TL_NO_DUPLICATES</code>  is specified, then
this function will ensure that no duplicates will be
present in the final trust list.
</p>
<p>If the flag <code class="code">GNUTLS_TL_NO_DUPLICATE_KEY</code>  is specified, then
this function will ensure that no certificates with the
same key are present in the final trust list.
</p>
<p>If either <code class="code">GNUTLS_TL_NO_DUPLICATE_KEY</code>  or <code class="code">GNUTLS_TL_NO_DUPLICATES</code> 
are given, <code class="code">gnutls_x509_trust_list_deinit()</code>  must be called with parameter
 <code class="code">all</code> being 1.
</p>
<p><strong class="strong">Returns:</strong> The number of added elements is returned; that includes
duplicate entries.
</p>
<p><strong class="strong">Since:</strong> 3.0.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005ftrust_005flist_005fadd_005fcrls-1"><span>gnutls_x509_trust_list_add_crls<a class="copiable-link" href="#gnutls_005fx509_005ftrust_005flist_005fadd_005fcrls-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005ftrust_005flist_005fadd_005fcrls"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005ftrust_005flist_005fadd_005fcrls-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_trust_list_add_crls</strong> <code class="def-code-arguments">(gnutls_x509_trust_list_t <var class="var">list</var>, const gnutls_x509_crl_t * <var class="var">crl_list</var>, unsigned <var class="var">crl_size</var>, unsigned int <var class="var">flags</var>, unsigned int <var class="var">verification_flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005ftrust_005flist_005fadd_005fcrls-1"> &para;</a></span></dt>
<dd><p><var class="var">list</var>: The list
</p>
<p><var class="var">crl_list</var>: A list of CRLs
</p>
<p><var class="var">crl_size</var>: The length of the CRL list
</p>
<p><var class="var">flags</var>: flags from <code class="code">gnutls_trust_list_flags_t</code> 
</p>
<p><var class="var">verification_flags</var>: gnutls_certificate_verify_flags if flags specifies GNUTLS_TL_VERIFY_CRL
</p>
<p>This function will add the given certificate revocation lists
to the trusted list. The CRLs in  <code class="code">crl_list</code> must not be deinitialized
during the lifetime of  <code class="code">list</code> .
</p>
<p>This function must be called after <code class="code">gnutls_x509_trust_list_add_cas()</code> 
to allow verifying the CRLs for validity. If the flag <code class="code">GNUTLS_TL_NO_DUPLICATES</code> 
is given, then the final CRL list will not contain duplicate entries.
</p>
<p>If the flag <code class="code">GNUTLS_TL_NO_DUPLICATES</code>  is given, <code class="code">gnutls_x509_trust_list_deinit()</code>  must be
called with parameter  <code class="code">all</code> being 1.
</p>
<p>If flag <code class="code">GNUTLS_TL_VERIFY_CRL</code>  is given the CRLs will be verified before being added,
and if verification fails, they will be skipped.
</p>
<p><strong class="strong">Returns:</strong> The number of added elements is returned; that includes
duplicate entries.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005ftrust_005flist_005fadd_005fnamed_005fcrt-1"><span>gnutls_x509_trust_list_add_named_crt<a class="copiable-link" href="#gnutls_005fx509_005ftrust_005flist_005fadd_005fnamed_005fcrt-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005ftrust_005flist_005fadd_005fnamed_005fcrt"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005ftrust_005flist_005fadd_005fnamed_005fcrt-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_trust_list_add_named_crt</strong> <code class="def-code-arguments">(gnutls_x509_trust_list_t <var class="var">list</var>, gnutls_x509_crt_t <var class="var">cert</var>, const void * <var class="var">name</var>, size_t <var class="var">name_size</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005ftrust_005flist_005fadd_005fnamed_005fcrt-1"> &para;</a></span></dt>
<dd><p><var class="var">list</var>: The list
</p>
<p><var class="var">cert</var>: A certificate
</p>
<p><var class="var">name</var>: An identifier for the certificate
</p>
<p><var class="var">name_size</var>: The size of the identifier
</p>
<p><var class="var">flags</var>: should be 0.
</p>
<p>This function will add the given certificate to the trusted
list and associate it with a name. The certificate will not be
be used for verification with <code class="code">gnutls_x509_trust_list_verify_crt()</code> 
but with <code class="code">gnutls_x509_trust_list_verify_named_crt()</code>  or
<code class="code">gnutls_x509_trust_list_verify_crt2()</code>  - the latter only since
GnuTLS 3.4.0 and if a hostname is provided.
</p>
<p>In principle this function can be used to set individual &quot;server&quot;
certificates that are trusted by the user for that specific server
but for no other purposes.
</p>
<p>The certificate  <code class="code">cert</code> must not be deinitialized during the lifetime
of the  <code class="code">list</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.0.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005ftrust_005flist_005fadd_005fsystem_005ftrust-1"><span>gnutls_x509_trust_list_add_system_trust<a class="copiable-link" href="#gnutls_005fx509_005ftrust_005flist_005fadd_005fsystem_005ftrust-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005ftrust_005flist_005fadd_005fsystem_005ftrust"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005ftrust_005flist_005fadd_005fsystem_005ftrust-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_trust_list_add_system_trust</strong> <code class="def-code-arguments">(gnutls_x509_trust_list_t <var class="var">list</var>, unsigned int <var class="var">tl_flags</var>, unsigned int <var class="var">tl_vflags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005ftrust_005flist_005fadd_005fsystem_005ftrust-1"> &para;</a></span></dt>
<dd><p><var class="var">list</var>: The structure of the list
</p>
<p><var class="var">tl_flags</var>: GNUTLS_TL_*
</p>
<p><var class="var">tl_vflags</var>: gnutls_certificate_verify_flags if flags specifies GNUTLS_TL_VERIFY_CRL
</p>
<p>This function adds the system&rsquo;s default trusted certificate
authorities to the trusted list. Note that on unsupported systems
this function returns <code class="code">GNUTLS_E_UNIMPLEMENTED_FEATURE</code> .
</p>
<p>This function implies the flag <code class="code">GNUTLS_TL_NO_DUPLICATES</code> .
</p>
<p><strong class="strong">Returns:</strong> The number of added elements or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 3.1
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005ftrust_005flist_005fadd_005ftrust_005fdir-1"><span>gnutls_x509_trust_list_add_trust_dir<a class="copiable-link" href="#gnutls_005fx509_005ftrust_005flist_005fadd_005ftrust_005fdir-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005ftrust_005flist_005fadd_005ftrust_005fdir"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005ftrust_005flist_005fadd_005ftrust_005fdir"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_trust_list_add_trust_dir</strong> <code class="def-code-arguments">(gnutls_x509_trust_list_t <var class="var">list</var>, const char * <var class="var">ca_dir</var>, const char * <var class="var">crl_dir</var>, gnutls_x509_crt_fmt_t <var class="var">type</var>, unsigned int <var class="var">tl_flags</var>, unsigned int <var class="var">tl_vflags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005ftrust_005flist_005fadd_005ftrust_005fdir"> &para;</a></span></dt>
<dd><p><var class="var">list</var>: The list
</p>
<p><var class="var">ca_dir</var>: A directory containing the CAs (optional)
</p>
<p><var class="var">crl_dir</var>: A directory containing a list of CRLs (optional)
</p>
<p><var class="var">type</var>: The format of the certificates
</p>
<p><var class="var">tl_flags</var>: flags from <code class="code">gnutls_trust_list_flags_t</code> 
</p>
<p><var class="var">tl_vflags</var>: gnutls_certificate_verify_flags if flags specifies GNUTLS_TL_VERIFY_CRL
</p>
<p>This function will add the given certificate authorities
to the trusted list. Only directories are accepted by
this function.
</p>
<p><strong class="strong">Returns:</strong> The number of added elements is returned.
</p>
<p><strong class="strong">Since:</strong> 3.3.6
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005ftrust_005flist_005fadd_005ftrust_005ffile-1"><span>gnutls_x509_trust_list_add_trust_file<a class="copiable-link" href="#gnutls_005fx509_005ftrust_005flist_005fadd_005ftrust_005ffile-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005ftrust_005flist_005fadd_005ftrust_005ffile"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005ftrust_005flist_005fadd_005ftrust_005ffile-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_trust_list_add_trust_file</strong> <code class="def-code-arguments">(gnutls_x509_trust_list_t <var class="var">list</var>, const char * <var class="var">ca_file</var>, const char * <var class="var">crl_file</var>, gnutls_x509_crt_fmt_t <var class="var">type</var>, unsigned int <var class="var">tl_flags</var>, unsigned int <var class="var">tl_vflags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005ftrust_005flist_005fadd_005ftrust_005ffile-1"> &para;</a></span></dt>
<dd><p><var class="var">list</var>: The list
</p>
<p><var class="var">ca_file</var>: A file containing a list of CAs (optional)
</p>
<p><var class="var">crl_file</var>: A file containing a list of CRLs (optional)
</p>
<p><var class="var">type</var>: The format of the certificates
</p>
<p><var class="var">tl_flags</var>: flags from <code class="code">gnutls_trust_list_flags_t</code> 
</p>
<p><var class="var">tl_vflags</var>: gnutls_certificate_verify_flags if flags specifies GNUTLS_TL_VERIFY_CRL
</p>
<p>This function will add the given certificate authorities
to the trusted list. PKCS <code class="code">11</code>  URLs are also accepted, instead
of files, by this function. A PKCS <code class="code">11</code>  URL implies a trust
database (a specially marked module in p11-kit); the URL &quot;pkcs11:&quot;
implies all trust databases in the system. Only a single URL specifying
trust databases can be set; they cannot be stacked with multiple calls.
</p>
<p><strong class="strong">Returns:</strong> The number of added elements is returned.
</p>
<p><strong class="strong">Since:</strong> 3.1
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005ftrust_005flist_005fadd_005ftrust_005fmem-1"><span>gnutls_x509_trust_list_add_trust_mem<a class="copiable-link" href="#gnutls_005fx509_005ftrust_005flist_005fadd_005ftrust_005fmem-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005ftrust_005flist_005fadd_005ftrust_005fmem"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005ftrust_005flist_005fadd_005ftrust_005fmem-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_trust_list_add_trust_mem</strong> <code class="def-code-arguments">(gnutls_x509_trust_list_t <var class="var">list</var>, const gnutls_datum_t * <var class="var">cas</var>, const gnutls_datum_t * <var class="var">crls</var>, gnutls_x509_crt_fmt_t <var class="var">type</var>, unsigned int <var class="var">tl_flags</var>, unsigned int <var class="var">tl_vflags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005ftrust_005flist_005fadd_005ftrust_005fmem-1"> &para;</a></span></dt>
<dd><p><var class="var">list</var>: The list
</p>
<p><var class="var">cas</var>: A buffer containing a list of CAs (optional)
</p>
<p><var class="var">crls</var>: A buffer containing a list of CRLs (optional)
</p>
<p><var class="var">type</var>: The format of the certificates
</p>
<p><var class="var">tl_flags</var>: flags from <code class="code">gnutls_trust_list_flags_t</code> 
</p>
<p><var class="var">tl_vflags</var>: gnutls_certificate_verify_flags if flags specifies GNUTLS_TL_VERIFY_CRL
</p>
<p>This function will add the given certificate authorities
to the trusted list. 
</p>
<p>If this function is used <code class="code">gnutls_x509_trust_list_deinit()</code>  must be called
with parameter  <code class="code">all</code> being 1.
</p>
<p><strong class="strong">Returns:</strong> The number of added elements is returned.
</p>
<p><strong class="strong">Since:</strong> 3.1
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005ftrust_005flist_005fdeinit-1"><span>gnutls_x509_trust_list_deinit<a class="copiable-link" href="#gnutls_005fx509_005ftrust_005flist_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005ftrust_005flist_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005ftrust_005flist_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_x509_trust_list_deinit</strong> <code class="def-code-arguments">(gnutls_x509_trust_list_t <var class="var">list</var>, unsigned int <var class="var">all</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005ftrust_005flist_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">list</var>: The list to be deinitialized
</p>
<p><var class="var">all</var>: if non-zero it will deinitialize all the certificates and CRLs contained in the structure.
</p>
<p>This function will deinitialize a trust list. Note that the
 <code class="code">all</code> flag should be typically non-zero unless you have specified
your certificates using <code class="code">gnutls_x509_trust_list_add_cas()</code>  and you
want to prevent them from being deinitialized by this function.
</p>
<p><strong class="strong">Since:</strong> 3.0.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005ftrust_005flist_005fget_005fissuer-1"><span>gnutls_x509_trust_list_get_issuer<a class="copiable-link" href="#gnutls_005fx509_005ftrust_005flist_005fget_005fissuer-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005ftrust_005flist_005fget_005fissuer"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005ftrust_005flist_005fget_005fissuer"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_trust_list_get_issuer</strong> <code class="def-code-arguments">(gnutls_x509_trust_list_t <var class="var">list</var>, gnutls_x509_crt_t <var class="var">cert</var>, gnutls_x509_crt_t * <var class="var">issuer</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005ftrust_005flist_005fget_005fissuer"> &para;</a></span></dt>
<dd><p><var class="var">list</var>: The list
</p>
<p><var class="var">cert</var>: is the certificate to find issuer for
</p>
<p><var class="var">issuer</var>: Will hold the issuer if any. Should be treated as constant
unless <code class="code">GNUTLS_TL_GET_COPY</code>  is set in  <code class="code">flags</code> .
</p>
<p><var class="var">flags</var>: flags from <code class="code">gnutls_trust_list_flags_t</code>  (<code class="code">GNUTLS_TL_GET_COPY</code>  is applicable)
</p>
<p>This function will find the issuer of the given certificate.
If the flag <code class="code">GNUTLS_TL_GET_COPY</code>  is specified a copy of the issuer
will be returned which must be freed using <code class="code">gnutls_x509_crt_deinit()</code> .
In that case the provided  <code class="code">issuer</code> must not be initialized.
</p>
<p>Note that the flag <code class="code">GNUTLS_TL_GET_COPY</code>  is required for this function
to work with PKCS<code class="code">11</code>  trust lists in a thread-safe way.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005ftrust_005flist_005fget_005fissuer_005fby_005fdn-1"><span>gnutls_x509_trust_list_get_issuer_by_dn<a class="copiable-link" href="#gnutls_005fx509_005ftrust_005flist_005fget_005fissuer_005fby_005fdn-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005ftrust_005flist_005fget_005fissuer_005fby_005fdn"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005ftrust_005flist_005fget_005fissuer_005fby_005fdn"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_trust_list_get_issuer_by_dn</strong> <code class="def-code-arguments">(gnutls_x509_trust_list_t <var class="var">list</var>, const gnutls_datum_t * <var class="var">dn</var>, gnutls_x509_crt_t * <var class="var">issuer</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005ftrust_005flist_005fget_005fissuer_005fby_005fdn"> &para;</a></span></dt>
<dd><p><var class="var">list</var>: The list
</p>
<p><var class="var">dn</var>: is the issuer&rsquo;s DN
</p>
<p><var class="var">issuer</var>: Will hold the issuer if any. Should be deallocated after use.
</p>
<p><var class="var">flags</var>: Use zero
</p>
<p>This function will find the issuer with the given name, and
return a copy of the issuer, which must be freed using <code class="code">gnutls_x509_crt_deinit()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005ftrust_005flist_005fget_005fissuer_005fby_005fsubject_005fkey_005fid-1"><span>gnutls_x509_trust_list_get_issuer_by_subject_key_id<a class="copiable-link" href="#gnutls_005fx509_005ftrust_005flist_005fget_005fissuer_005fby_005fsubject_005fkey_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005ftrust_005flist_005fget_005fissuer_005fby_005fsubject_005fkey_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005ftrust_005flist_005fget_005fissuer_005fby_005fsubject_005fkey_005fid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_trust_list_get_issuer_by_subject_key_id</strong> <code class="def-code-arguments">(gnutls_x509_trust_list_t <var class="var">list</var>, const gnutls_datum_t * <var class="var">dn</var>, const gnutls_datum_t * <var class="var">spki</var>, gnutls_x509_crt_t * <var class="var">issuer</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005ftrust_005flist_005fget_005fissuer_005fby_005fsubject_005fkey_005fid"> &para;</a></span></dt>
<dd><p><var class="var">list</var>: The list
</p>
<p><var class="var">dn</var>: is the issuer&rsquo;s DN (may be <code class="code">NULL</code> )
</p>
<p><var class="var">spki</var>: is the subject key ID
</p>
<p><var class="var">issuer</var>: Will hold the issuer if any. Should be deallocated after use.
</p>
<p><var class="var">flags</var>: Use zero
</p>
<p>This function will find the issuer with the given name and subject key ID, and
return a copy of the issuer, which must be freed using <code class="code">gnutls_x509_crt_deinit()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.4.2
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005ftrust_005flist_005fget_005fptr-1"><span>gnutls_x509_trust_list_get_ptr<a class="copiable-link" href="#gnutls_005fx509_005ftrust_005flist_005fget_005fptr-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005ftrust_005flist_005fget_005fptr"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005ftrust_005flist_005fget_005fptr"><span class="category-def">Function: </span><span><code class="def-type">void *</code> <strong class="def-name">gnutls_x509_trust_list_get_ptr</strong> <code class="def-code-arguments">(gnutls_x509_trust_list_t <var class="var">tlist</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005ftrust_005flist_005fget_005fptr"> &para;</a></span></dt>
<dd><p><var class="var">tlist</var>: is a <code class="code">gnutls_x509_trust_list_t</code>  type.
</p>
<p>Get user pointer for tlist. Useful in callback function
gnutls_x509_trust_list_set_getissuer_function.
This is the pointer set with <code class="code">gnutls_x509_trust_list_set_ptr()</code> .
</p>
<p><strong class="strong">Returns:</strong> the user given pointer from the tlist structure, or
<code class="code">NULL</code>  if it was never set.
</p>
<p><strong class="strong">Since:</strong> 3.7.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005ftrust_005flist_005finit-1"><span>gnutls_x509_trust_list_init<a class="copiable-link" href="#gnutls_005fx509_005ftrust_005flist_005finit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005ftrust_005flist_005finit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005ftrust_005flist_005finit"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_trust_list_init</strong> <code class="def-code-arguments">(gnutls_x509_trust_list_t * <var class="var">list</var>, unsigned int <var class="var">size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005ftrust_005flist_005finit"> &para;</a></span></dt>
<dd><p><var class="var">list</var>: A pointer to the type to be initialized
</p>
<p><var class="var">size</var>: The size of the internal hash table. Use (0) for default size.
</p>
<p>This function will initialize an X.509 trust list structure.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.0.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005ftrust_005flist_005fiter_005fdeinit-1"><span>gnutls_x509_trust_list_iter_deinit<a class="copiable-link" href="#gnutls_005fx509_005ftrust_005flist_005fiter_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005ftrust_005flist_005fiter_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005ftrust_005flist_005fiter_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_x509_trust_list_iter_deinit</strong> <code class="def-code-arguments">(gnutls_x509_trust_list_iter_t <var class="var">iter</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005ftrust_005flist_005fiter_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">iter</var>: The iterator structure to be deinitialized
</p>
<p>This function will deinitialize an iterator structure.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005ftrust_005flist_005fiter_005fget_005fca-1"><span>gnutls_x509_trust_list_iter_get_ca<a class="copiable-link" href="#gnutls_005fx509_005ftrust_005flist_005fiter_005fget_005fca-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005ftrust_005flist_005fiter_005fget_005fca"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005ftrust_005flist_005fiter_005fget_005fca"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_trust_list_iter_get_ca</strong> <code class="def-code-arguments">(gnutls_x509_trust_list_t <var class="var">list</var>, gnutls_x509_trust_list_iter_t * <var class="var">iter</var>, gnutls_x509_crt_t * <var class="var">crt</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005ftrust_005flist_005fiter_005fget_005fca"> &para;</a></span></dt>
<dd><p><var class="var">list</var>: The list
</p>
<p><var class="var">iter</var>: A pointer to an iterator (initially the iterator should be <code class="code">NULL</code> )
</p>
<p><var class="var">crt</var>: where the certificate will be copied
</p>
<p>This function obtains a certificate in the trust list and advances the
iterator to the next certificate. The certificate returned in  <code class="code">crt</code> must be
deallocated with <code class="code">gnutls_x509_crt_deinit()</code> .
</p>
<p>When past the last element is accessed <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> 
is returned and the iterator is reset.
</p>
<p>The iterator is deinitialized and reset to <code class="code">NULL</code>  automatically by this
function after iterating through all elements until
<code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  is returned. If the iteration is
aborted early, it must be manually deinitialized using
<code class="code">gnutls_x509_trust_list_iter_deinit()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005ftrust_005flist_005fremove_005fcas-1"><span>gnutls_x509_trust_list_remove_cas<a class="copiable-link" href="#gnutls_005fx509_005ftrust_005flist_005fremove_005fcas-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005ftrust_005flist_005fremove_005fcas"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005ftrust_005flist_005fremove_005fcas"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_trust_list_remove_cas</strong> <code class="def-code-arguments">(gnutls_x509_trust_list_t <var class="var">list</var>, const gnutls_x509_crt_t * <var class="var">clist</var>, unsigned <var class="var">clist_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005ftrust_005flist_005fremove_005fcas"> &para;</a></span></dt>
<dd><p><var class="var">list</var>: The list
</p>
<p><var class="var">clist</var>: A list of CAs
</p>
<p><var class="var">clist_size</var>: The length of the CA list
</p>
<p>This function will remove the given certificate authorities
from the trusted list.
</p>
<p>Note that this function can accept certificates and authorities
not yet known. In that case they will be kept in a separate
block list that will be used during certificate verification.
Unlike <code class="code">gnutls_x509_trust_list_add_cas()</code>  there is no deinitialization
restriction for  certificate list provided in this function.
</p>
<p><strong class="strong">Returns:</strong> The number of removed elements is returned.
</p>
<p><strong class="strong">Since:</strong> 3.1.10
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005ftrust_005flist_005fremove_005ftrust_005ffile-1"><span>gnutls_x509_trust_list_remove_trust_file<a class="copiable-link" href="#gnutls_005fx509_005ftrust_005flist_005fremove_005ftrust_005ffile-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005ftrust_005flist_005fremove_005ftrust_005ffile"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005ftrust_005flist_005fremove_005ftrust_005ffile"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_trust_list_remove_trust_file</strong> <code class="def-code-arguments">(gnutls_x509_trust_list_t <var class="var">list</var>, const char * <var class="var">ca_file</var>, gnutls_x509_crt_fmt_t <var class="var">type</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005ftrust_005flist_005fremove_005ftrust_005ffile"> &para;</a></span></dt>
<dd><p><var class="var">list</var>: The list
</p>
<p><var class="var">ca_file</var>: A file containing a list of CAs
</p>
<p><var class="var">type</var>: The format of the certificates
</p>
<p>This function will remove the given certificate authorities
from the trusted list, and add them into a block list when needed. 
PKCS 11 URLs are also accepted, instead
of files, by this function.
</p>
<p>See also <code class="code">gnutls_x509_trust_list_remove_cas()</code> .
</p>
<p><strong class="strong">Returns:</strong> The number of added elements is returned.
</p>
<p><strong class="strong">Since:</strong> 3.1.10
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005ftrust_005flist_005fremove_005ftrust_005fmem-1"><span>gnutls_x509_trust_list_remove_trust_mem<a class="copiable-link" href="#gnutls_005fx509_005ftrust_005flist_005fremove_005ftrust_005fmem-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005ftrust_005flist_005fremove_005ftrust_005fmem"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005ftrust_005flist_005fremove_005ftrust_005fmem"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_trust_list_remove_trust_mem</strong> <code class="def-code-arguments">(gnutls_x509_trust_list_t <var class="var">list</var>, const gnutls_datum_t * <var class="var">cas</var>, gnutls_x509_crt_fmt_t <var class="var">type</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005ftrust_005flist_005fremove_005ftrust_005fmem"> &para;</a></span></dt>
<dd><p><var class="var">list</var>: The list
</p>
<p><var class="var">cas</var>: A buffer containing a list of CAs (optional)
</p>
<p><var class="var">type</var>: The format of the certificates
</p>
<p>This function will remove the provided certificate authorities
from the trusted list, and add them into a block list when needed. 
</p>
<p>See also <code class="code">gnutls_x509_trust_list_remove_cas()</code> .
</p>
<p><strong class="strong">Returns:</strong> The number of removed elements is returned.
</p>
<p><strong class="strong">Since:</strong> 3.1.10
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005ftrust_005flist_005fset_005fgetissuer_005ffunction-1"><span>gnutls_x509_trust_list_set_getissuer_function<a class="copiable-link" href="#gnutls_005fx509_005ftrust_005flist_005fset_005fgetissuer_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005ftrust_005flist_005fset_005fgetissuer_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005ftrust_005flist_005fset_005fgetissuer_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_x509_trust_list_set_getissuer_function</strong> <code class="def-code-arguments">(gnutls_x509_trust_list_t <var class="var">tlist</var>, gnutls_x509_trust_list_getissuer_function * <var class="var">func</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005ftrust_005flist_005fset_005fgetissuer_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">tlist</var>: is a <code class="code">gnutls_x509_trust_list_t</code>  type.
</p>
<p><var class="var">func</var>: is the callback function
</p>
<p>This function sets a callback to be called when the peer&rsquo;s certificate
chain is incomplete due a missing intermediate certificate. The callback
may provide the missing certificate for use during verification.
</p>
<p>The callback&rsquo;s function prototype is defined in gnutls/x509.h as:
</p>
<p>int (*callback)(gnutls_x509_trust_list_t list,
const gnutls_x509_crt_t cert,
gnutls_x509_crt_t **issuers,
unsigned int *issuers_size);
</p>
<p>If the callback function is provided then gnutls will call it during the
certificate verification procedure. The callback may wish to use
<code class="code">gnutls_x509_crt_get_authority_info_access()</code>  to get a URI from which
to attempt to download the missing issuer certificate, if available.
</p>
<p>On a successful call, the callback shall set &rsquo;*issuers&rsquo; and &rsquo;*issuers_size&rsquo;
even if the result is empty; in that case &rsquo;*issuers&rsquo; will point to <code class="code">NULL</code>  and
&rsquo;*issuers_size&rsquo; will be 0.  Otherwise, the &rsquo;*issuers&rsquo; array shall be
allocated using <code class="code">gnutls_x509_crt_list_import2()</code> . The ownership of both the
array and the elements is transferred to the caller and thus the application
does not need to maintain the memory after the call.
</p>
<p>The callback function should return 0 if the attempt to retrieve the issuer
certificates for &rsquo;crt&rsquo; succeeded, or non-zero to indicate any error occurred
during the attempt. In the latter case, &rsquo;*issuers&rsquo; and &rsquo;*issuers_size&rsquo; are
not set.
</p>
<p><strong class="strong">Since:</strong> 3.7.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005ftrust_005flist_005fset_005fptr-1"><span>gnutls_x509_trust_list_set_ptr<a class="copiable-link" href="#gnutls_005fx509_005ftrust_005flist_005fset_005fptr-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005ftrust_005flist_005fset_005fptr"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005ftrust_005flist_005fset_005fptr"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_x509_trust_list_set_ptr</strong> <code class="def-code-arguments">(gnutls_x509_trust_list_t <var class="var">tlist</var>, void * <var class="var">ptr</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005ftrust_005flist_005fset_005fptr"> &para;</a></span></dt>
<dd><p><var class="var">tlist</var>: is a <code class="code">gnutls_x509_trust_list_t</code>  type.
</p>
<p><var class="var">ptr</var>: is the user pointer
</p>
<p>This function will set (associate) the user given pointer  <code class="code">ptr</code> to
the tlist structure. This pointer can be accessed with
<code class="code">gnutls_x509_trust_list_get_ptr()</code> . Useful in the callback function
gnutls_x509_trust_list_set_getissuer_function.
</p>
<p><strong class="strong">Since:</strong> 3.7.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005ftrust_005flist_005fverify_005fcrt-1"><span>gnutls_x509_trust_list_verify_crt<a class="copiable-link" href="#gnutls_005fx509_005ftrust_005flist_005fverify_005fcrt-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005ftrust_005flist_005fverify_005fcrt"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005ftrust_005flist_005fverify_005fcrt-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_trust_list_verify_crt</strong> <code class="def-code-arguments">(gnutls_x509_trust_list_t <var class="var">list</var>, gnutls_x509_crt_t * <var class="var">cert_list</var>, unsigned int <var class="var">cert_list_size</var>, unsigned int <var class="var">flags</var>, unsigned int * <var class="var">voutput</var>, gnutls_verify_output_function <var class="var">func</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005ftrust_005flist_005fverify_005fcrt-1"> &para;</a></span></dt>
<dd><p><var class="var">list</var>: The list
</p>
<p><var class="var">cert_list</var>: is the certificate list to be verified
</p>
<p><var class="var">cert_list_size</var>: is the certificate list size
</p>
<p><var class="var">flags</var>: Flags that may be used to change the verification algorithm. Use OR of the gnutls_certificate_verify_flags enumerations.
</p>
<p><var class="var">voutput</var>: will hold the certificate verification output.
</p>
<p><var class="var">func</var>: If non-null will be called on each chain element verification with the output.
</p>
<p>This function will try to verify the given certificate and return
its status. The  <code class="code">voutput</code> parameter will hold an OR&rsquo;ed sequence of
<code class="code">gnutls_certificate_status_t</code>  flags.
</p>
<p>The details of the verification are the same as in <code class="code">gnutls_x509_trust_list_verify_crt2()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005ftrust_005flist_005fverify_005fcrt2-1"><span>gnutls_x509_trust_list_verify_crt2<a class="copiable-link" href="#gnutls_005fx509_005ftrust_005flist_005fverify_005fcrt2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005ftrust_005flist_005fverify_005fcrt2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005ftrust_005flist_005fverify_005fcrt2-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_trust_list_verify_crt2</strong> <code class="def-code-arguments">(gnutls_x509_trust_list_t <var class="var">list</var>, gnutls_x509_crt_t * <var class="var">cert_list</var>, unsigned int <var class="var">cert_list_size</var>, gnutls_typed_vdata_st * <var class="var">data</var>, unsigned int <var class="var">elements</var>, unsigned int <var class="var">flags</var>, unsigned int * <var class="var">voutput</var>, gnutls_verify_output_function <var class="var">func</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005ftrust_005flist_005fverify_005fcrt2-1"> &para;</a></span></dt>
<dd><p><var class="var">list</var>: The list
</p>
<p><var class="var">cert_list</var>: is the certificate list to be verified
</p>
<p><var class="var">cert_list_size</var>: is the certificate list size
</p>
<p><var class="var">data</var>: an array of typed data
</p>
<p><var class="var">elements</var>: the number of data elements
</p>
<p><var class="var">flags</var>: Flags that may be used to change the verification algorithm. Use OR of the gnutls_certificate_verify_flags enumerations.
</p>
<p><var class="var">voutput</var>: will hold the certificate verification output.
</p>
<p><var class="var">func</var>: If non-null will be called on each chain element verification with the output.
</p>
<p>This function will attempt to verify the given certificate chain and return
its status. The  <code class="code">voutput</code> parameter will hold an OR&rsquo;ed sequence of
<code class="code">gnutls_certificate_status_t</code>  flags.
</p>
<p>When a certificate chain of  <code class="code">cert_list_size</code> with more than one certificates is
provided, the verification status will apply to the first certificate in the chain
that failed verification. The verification process starts from the end of the chain
(from CA to end certificate). The first certificate in the chain must be the end-certificate
while the rest of the members may be sorted or not.
</p>
<p>Additionally a certificate verification profile can be specified
from the ones in <code class="code">gnutls_certificate_verification_profiles_t</code>  by
ORing the result of <code class="code">GNUTLS_PROFILE_TO_VFLAGS()</code>  to the verification
flags.
</p>
<p>Additional verification parameters are possible via the  <code class="code">data</code> types; the
acceptable types are <code class="code">GNUTLS_DT_DNS_HOSTNAME</code> , <code class="code">GNUTLS_DT_IP_ADDRESS</code>  and <code class="code">GNUTLS_DT_KEY_PURPOSE_OID</code> .
The former accepts as data a null-terminated hostname, and the latter a null-terminated
object identifier (e.g., <code class="code">GNUTLS_KP_TLS_WWW_SERVER</code> ).
If a DNS hostname is provided then this function will compare
the hostname in the end certificate against the given. If names do not match the
<code class="code">GNUTLS_CERT_UNEXPECTED_OWNER</code>  status flag will be set. In addition it
will consider certificates provided with <code class="code">gnutls_x509_trust_list_add_named_crt()</code> .
</p>
<p>If a key purpose OID is provided and the end-certificate contains the extended key
usage PKIX extension, it will be required to match the provided OID
or be marked for any purpose, otherwise verification will fail with 
<code class="code">GNUTLS_CERT_PURPOSE_MISMATCH</code>  status.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value. Note that verification failure will not result to an
error code, only  <code class="code">voutput</code> will be updated.
</p>
<p><strong class="strong">Since:</strong> 3.3.8
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005ftrust_005flist_005fverify_005fnamed_005fcrt-1"><span>gnutls_x509_trust_list_verify_named_crt<a class="copiable-link" href="#gnutls_005fx509_005ftrust_005flist_005fverify_005fnamed_005fcrt-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005ftrust_005flist_005fverify_005fnamed_005fcrt"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005ftrust_005flist_005fverify_005fnamed_005fcrt-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_trust_list_verify_named_crt</strong> <code class="def-code-arguments">(gnutls_x509_trust_list_t <var class="var">list</var>, gnutls_x509_crt_t <var class="var">cert</var>, const void * <var class="var">name</var>, size_t <var class="var">name_size</var>, unsigned int <var class="var">flags</var>, unsigned int * <var class="var">voutput</var>, gnutls_verify_output_function <var class="var">func</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005ftrust_005flist_005fverify_005fnamed_005fcrt-1"> &para;</a></span></dt>
<dd><p><var class="var">list</var>: The list
</p>
<p><var class="var">cert</var>: is the certificate to be verified
</p>
<p><var class="var">name</var>: is the certificate&rsquo;s name
</p>
<p><var class="var">name_size</var>: is the certificate&rsquo;s name size
</p>
<p><var class="var">flags</var>: Flags that may be used to change the verification algorithm. Use OR of the gnutls_certificate_verify_flags enumerations.
</p>
<p><var class="var">voutput</var>: will hold the certificate verification output.
</p>
<p><var class="var">func</var>: If non-null will be called on each chain element verification with the output.
</p>
<p>This function will try to find a certificate that is associated with the provided
name &ndash;see <code class="code">gnutls_x509_trust_list_add_named_crt()</code> . If a match is found the
certificate is considered valid. In addition to that this function will also 
check CRLs. The  <code class="code">voutput</code> parameter will hold an OR&rsquo;ed sequence of 
<code class="code">gnutls_certificate_status_t</code>  flags.
</p>
<p>Additionally a certificate verification profile can be specified
from the ones in <code class="code">gnutls_certificate_verification_profiles_t</code>  by
ORing the result of <code class="code">GNUTLS_PROFILE_TO_VFLAGS()</code>  to the verification
flags.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.0.0
</p></dd></dl>


<hr>
</div>
<div class="section-level-extent" id="PKCS-7-API">
<div class="nav-panel">
<p>
Next: <a href="#OCSP-API" accesskey="n" rel="next"><abbr class="acronym">OCSP</abbr> API</a>, Previous: <a href="#X509-certificate-API" accesskey="p" rel="prev"><abbr class="acronym">X.509</abbr> certificate API</a>, Up: <a href="#API-reference" accesskey="u" rel="up">API reference</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="PKCS-7-API-1"><span>E.4 <abbr class="acronym">PKCS</abbr> 7 API<a class="copiable-link" href="#PKCS-7-API-1"> &para;</a></span></h3>

<p>The following functions are to be used for PKCS 7 structures handling.
Their prototypes lie in <samp class="file">gnutls/pkcs7.h</samp>.
</p>

<h4 class="subheading" id="gnutls_005fpkcs7_005fadd_005fattr-1"><span>gnutls_pkcs7_add_attr<a class="copiable-link" href="#gnutls_005fpkcs7_005fadd_005fattr-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs7_005fadd_005fattr"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs7_005fadd_005fattr"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs7_add_attr</strong> <code class="def-code-arguments">(gnutls_pkcs7_attrs_t * <var class="var">list</var>, const char * <var class="var">oid</var>, gnutls_datum_t * <var class="var">data</var>, unsigned <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs7_005fadd_005fattr"> &para;</a></span></dt>
<dd><p><var class="var">list</var>: A list of existing attributes or pointer to <code class="code">NULL</code>  for the first one
</p>
<p><var class="var">oid</var>: the OID of the attribute to be set
</p>
<p><var class="var">data</var>: the raw (DER-encoded) data of the attribute to be set
</p>
<p><var class="var">flags</var>: zero or <code class="code">GNUTLS_PKCS7_ATTR_ENCODE_OCTET_STRING</code> 
</p>
<p>This function will set a PKCS <code class="code">7</code>  attribute in the provided list.
If this function fails, the previous list would be deallocated.
</p>
<p>Note that any attributes set with this function must either be
DER or BER encoded, unless a special flag is present.
</p>
<p><strong class="strong">Returns:</strong> On success, the new list head, otherwise <code class="code">NULL</code> .
</p>
<p><strong class="strong">Since:</strong> 3.4.2
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs7_005fattrs_005fdeinit-1"><span>gnutls_pkcs7_attrs_deinit<a class="copiable-link" href="#gnutls_005fpkcs7_005fattrs_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs7_005fattrs_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs7_005fattrs_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_pkcs7_attrs_deinit</strong> <code class="def-code-arguments">(gnutls_pkcs7_attrs_t <var class="var">list</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs7_005fattrs_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">list</var>: A list of existing attributes
</p>
<p>This function will clear a PKCS <code class="code">7</code>  attribute list.
</p>
<p><strong class="strong">Since:</strong> 3.4.2
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs7_005fdeinit-1"><span>gnutls_pkcs7_deinit<a class="copiable-link" href="#gnutls_005fpkcs7_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs7_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs7_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_pkcs7_deinit</strong> <code class="def-code-arguments">(gnutls_pkcs7_t <var class="var">pkcs7</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs7_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">pkcs7</var>: the type to be deinitialized
</p>
<p>This function will deinitialize a PKCS7 type.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs7_005fdelete_005fcrl-1"><span>gnutls_pkcs7_delete_crl<a class="copiable-link" href="#gnutls_005fpkcs7_005fdelete_005fcrl-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs7_005fdelete_005fcrl"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs7_005fdelete_005fcrl"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs7_delete_crl</strong> <code class="def-code-arguments">(gnutls_pkcs7_t <var class="var">pkcs7</var>, int <var class="var">indx</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs7_005fdelete_005fcrl"> &para;</a></span></dt>
<dd><p><var class="var">pkcs7</var>: The pkcs7 type
</p>
<p><var class="var">indx</var>: the index of the crl to delete
</p>
<p>This function will delete a crl from a PKCS7 or RFC2630 crl set.
Index starts from 0. Returns 0 on success.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs7_005fdelete_005fcrt-1"><span>gnutls_pkcs7_delete_crt<a class="copiable-link" href="#gnutls_005fpkcs7_005fdelete_005fcrt-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs7_005fdelete_005fcrt"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs7_005fdelete_005fcrt"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs7_delete_crt</strong> <code class="def-code-arguments">(gnutls_pkcs7_t <var class="var">pkcs7</var>, int <var class="var">indx</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs7_005fdelete_005fcrt"> &para;</a></span></dt>
<dd><p><var class="var">pkcs7</var>: The pkcs7 type
</p>
<p><var class="var">indx</var>: the index of the certificate to delete
</p>
<p>This function will delete a certificate from a PKCS7 or RFC2630
certificate set.  Index starts from 0. Returns 0 on success.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs7_005fexport-1"><span>gnutls_pkcs7_export<a class="copiable-link" href="#gnutls_005fpkcs7_005fexport-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs7_005fexport"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs7_005fexport"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs7_export</strong> <code class="def-code-arguments">(gnutls_pkcs7_t <var class="var">pkcs7</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, void * <var class="var">output_data</var>, size_t * <var class="var">output_data_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs7_005fexport"> &para;</a></span></dt>
<dd><p><var class="var">pkcs7</var>: The pkcs7 type
</p>
<p><var class="var">format</var>: the format of output params. One of PEM or DER.
</p>
<p><var class="var">output_data</var>: will contain a structure PEM or DER encoded
</p>
<p><var class="var">output_data_size</var>: holds the size of output_data (and will be
replaced by the actual size of parameters)
</p>
<p>This function will export the pkcs7 structure to DER or PEM format.
</p>
<p>If the buffer provided is not long enough to hold the output, then
* <code class="code">output_data_size</code> is updated and <code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code> 
will be returned.
</p>
<p>If the structure is PEM encoded, it will have a header
of &quot;BEGIN PKCS7&quot;.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs7_005fexport2-1"><span>gnutls_pkcs7_export2<a class="copiable-link" href="#gnutls_005fpkcs7_005fexport2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs7_005fexport2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs7_005fexport2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs7_export2</strong> <code class="def-code-arguments">(gnutls_pkcs7_t <var class="var">pkcs7</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, gnutls_datum_t * <var class="var">out</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs7_005fexport2"> &para;</a></span></dt>
<dd><p><var class="var">pkcs7</var>: The pkcs7 type
</p>
<p><var class="var">format</var>: the format of output params. One of PEM or DER.
</p>
<p><var class="var">out</var>: will contain a structure PEM or DER encoded
</p>
<p>This function will export the pkcs7 structure to DER or PEM format.
</p>
<p>The output buffer is allocated using <code class="code">gnutls_malloc()</code> .
</p>
<p>If the structure is PEM encoded, it will have a header
of &quot;BEGIN PKCS7&quot;.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.1.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs7_005fget_005fattr-1"><span>gnutls_pkcs7_get_attr<a class="copiable-link" href="#gnutls_005fpkcs7_005fget_005fattr-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs7_005fget_005fattr"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs7_005fget_005fattr"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs7_get_attr</strong> <code class="def-code-arguments">(gnutls_pkcs7_attrs_t <var class="var">list</var>, unsigned <var class="var">idx</var>, char ** <var class="var">oid</var>, gnutls_datum_t * <var class="var">data</var>, unsigned <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs7_005fget_005fattr"> &para;</a></span></dt>
<dd><p><var class="var">list</var>: A list of existing attributes or <code class="code">NULL</code>  for the first one
</p>
<p><var class="var">idx</var>: the index of the attribute to get
</p>
<p><var class="var">oid</var>: the OID of the attribute (read-only)
</p>
<p><var class="var">data</var>: the raw data of the attribute
</p>
<p><var class="var">flags</var>: zero or <code class="code">GNUTLS_PKCS7_ATTR_ENCODE_OCTET_STRING</code> 
</p>
<p>This function will get a PKCS <code class="code">7</code>  attribute from the provided list.
The OID is a constant string, but data will be allocated and must be
deinitialized by the caller.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value. <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  is returned
if there are no data in the current index.
</p>
<p><strong class="strong">Since:</strong> 3.4.2
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs7_005fget_005fcrl_005fcount-1"><span>gnutls_pkcs7_get_crl_count<a class="copiable-link" href="#gnutls_005fpkcs7_005fget_005fcrl_005fcount-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs7_005fget_005fcrl_005fcount"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs7_005fget_005fcrl_005fcount"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs7_get_crl_count</strong> <code class="def-code-arguments">(gnutls_pkcs7_t <var class="var">pkcs7</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs7_005fget_005fcrl_005fcount"> &para;</a></span></dt>
<dd><p><var class="var">pkcs7</var>: The pkcs7 type
</p>
<p>This function will return the number of certificates in the PKCS7
or RFC2630 crl set.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs7_005fget_005fcrl_005fraw-1"><span>gnutls_pkcs7_get_crl_raw<a class="copiable-link" href="#gnutls_005fpkcs7_005fget_005fcrl_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs7_005fget_005fcrl_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs7_005fget_005fcrl_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs7_get_crl_raw</strong> <code class="def-code-arguments">(gnutls_pkcs7_t <var class="var">pkcs7</var>, unsigned <var class="var">indx</var>, void * <var class="var">crl</var>, size_t * <var class="var">crl_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs7_005fget_005fcrl_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">pkcs7</var>: The pkcs7 type
</p>
<p><var class="var">indx</var>: contains the index of the crl to extract
</p>
<p><var class="var">crl</var>: the contents of the crl will be copied there (may be null)
</p>
<p><var class="var">crl_size</var>: should hold the size of the crl
</p>
<p>This function will return a crl of the PKCS7 or RFC2630 crl set.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.  If the provided buffer is not long enough,
then  <code class="code">crl_size</code> is updated and <code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  is
returned.  After the last crl has been read
<code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  will be returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs7_005fget_005fcrl_005fraw2-1"><span>gnutls_pkcs7_get_crl_raw2<a class="copiable-link" href="#gnutls_005fpkcs7_005fget_005fcrl_005fraw2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs7_005fget_005fcrl_005fraw2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs7_005fget_005fcrl_005fraw2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs7_get_crl_raw2</strong> <code class="def-code-arguments">(gnutls_pkcs7_t <var class="var">pkcs7</var>, unsigned <var class="var">indx</var>, gnutls_datum_t * <var class="var">crl</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs7_005fget_005fcrl_005fraw2"> &para;</a></span></dt>
<dd><p><var class="var">pkcs7</var>: The pkcs7 type
</p>
<p><var class="var">indx</var>: contains the index of the crl to extract
</p>
<p><var class="var">crl</var>: will contain the contents of the CRL in an allocated buffer
</p>
<p>This function will return a DER encoded CRL of the PKCS7 or RFC2630 crl set.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.  After the last crl has been read
<code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  will be returned.
</p>
<p><strong class="strong">Since:</strong> 3.4.2
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs7_005fget_005fcrt_005fcount-1"><span>gnutls_pkcs7_get_crt_count<a class="copiable-link" href="#gnutls_005fpkcs7_005fget_005fcrt_005fcount-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs7_005fget_005fcrt_005fcount"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs7_005fget_005fcrt_005fcount"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs7_get_crt_count</strong> <code class="def-code-arguments">(gnutls_pkcs7_t <var class="var">pkcs7</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs7_005fget_005fcrt_005fcount"> &para;</a></span></dt>
<dd><p><var class="var">pkcs7</var>: should contain a <code class="code">gnutls_pkcs7_t</code>  type
</p>
<p>This function will return the number of certificates in the PKCS7
or RFC2630 certificate set.
</p>
<p><strong class="strong">Returns:</strong> On success, a positive number is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs7_005fget_005fcrt_005fraw-1"><span>gnutls_pkcs7_get_crt_raw<a class="copiable-link" href="#gnutls_005fpkcs7_005fget_005fcrt_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs7_005fget_005fcrt_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs7_005fget_005fcrt_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs7_get_crt_raw</strong> <code class="def-code-arguments">(gnutls_pkcs7_t <var class="var">pkcs7</var>, unsigned <var class="var">indx</var>, void * <var class="var">certificate</var>, size_t * <var class="var">certificate_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs7_005fget_005fcrt_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">pkcs7</var>: should contain a gnutls_pkcs7_t type
</p>
<p><var class="var">indx</var>: contains the index of the certificate to extract
</p>
<p><var class="var">certificate</var>: the contents of the certificate will be copied
there (may be null)
</p>
<p><var class="var">certificate_size</var>: should hold the size of the certificate
</p>
<p>This function will return a certificate of the PKCS7 or RFC2630
certificate set.
</p>
<p>After the last certificate has been read
<code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  will be returned.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.  If the provided buffer is not long enough,
then  <code class="code">certificate_size</code> is updated and
<code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs7_005fget_005fcrt_005fraw2-1"><span>gnutls_pkcs7_get_crt_raw2<a class="copiable-link" href="#gnutls_005fpkcs7_005fget_005fcrt_005fraw2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs7_005fget_005fcrt_005fraw2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs7_005fget_005fcrt_005fraw2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs7_get_crt_raw2</strong> <code class="def-code-arguments">(gnutls_pkcs7_t <var class="var">pkcs7</var>, unsigned <var class="var">indx</var>, gnutls_datum_t * <var class="var">cert</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs7_005fget_005fcrt_005fraw2"> &para;</a></span></dt>
<dd><p><var class="var">pkcs7</var>: should contain a gnutls_pkcs7_t type
</p>
<p><var class="var">indx</var>: contains the index of the certificate to extract
</p>
<p><var class="var">cert</var>: will hold the contents of the certificate; must be deallocated with <code class="code">gnutls_free()</code> 
</p>
<p>This function will return a certificate of the PKCS7 or RFC2630
certificate set.
</p>
<p>After the last certificate has been read
<code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  will be returned.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.  If the provided buffer is not long enough,
then  <code class="code">certificate_size</code> is updated and
<code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  is returned.
</p>
<p><strong class="strong">Since:</strong> 3.4.2
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs7_005fget_005fembedded_005fdata-1"><span>gnutls_pkcs7_get_embedded_data<a class="copiable-link" href="#gnutls_005fpkcs7_005fget_005fembedded_005fdata-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs7_005fget_005fembedded_005fdata"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs7_005fget_005fembedded_005fdata"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs7_get_embedded_data</strong> <code class="def-code-arguments">(gnutls_pkcs7_t <var class="var">pkcs7</var>, unsigned <var class="var">flags</var>, gnutls_datum_t * <var class="var">data</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs7_005fget_005fembedded_005fdata"> &para;</a></span></dt>
<dd><p><var class="var">pkcs7</var>: should contain a gnutls_pkcs7_t type
</p>
<p><var class="var">flags</var>: must be zero or <code class="code">GNUTLS_PKCS7_EDATA_GET_RAW</code> 
</p>
<p><var class="var">data</var>: will hold the embedded data in the provided structure
</p>
<p>This function will return the data embedded in the signature of
the PKCS7 structure. If no data are available then
<code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  will be returned.
</p>
<p>The returned data must be de-allocated using <code class="code">gnutls_free()</code> .
</p>
<p>Note, that this function returns the exact same data that are
authenticated. If the <code class="code">GNUTLS_PKCS7_EDATA_GET_RAW</code>  flag is provided,
the returned data will be including the wrapping tag/value as
they are encoded in the structure.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.4.8
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs7_005fget_005fembedded_005fdata_005foid-1"><span>gnutls_pkcs7_get_embedded_data_oid<a class="copiable-link" href="#gnutls_005fpkcs7_005fget_005fembedded_005fdata_005foid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs7_005fget_005fembedded_005fdata_005foid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs7_005fget_005fembedded_005fdata_005foid"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_pkcs7_get_embedded_data_oid</strong> <code class="def-code-arguments">(gnutls_pkcs7_t <var class="var">pkcs7</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs7_005fget_005fembedded_005fdata_005foid"> &para;</a></span></dt>
<dd><p><var class="var">pkcs7</var>: should contain a gnutls_pkcs7_t type
</p>
<p>This function will return the OID of the data embedded in the signature of
the PKCS7 structure. If no data are available then <code class="code">NULL</code>  will be
returned. The returned value will be valid during the lifetime
of the  <code class="code">pkcs7</code> structure.
</p>
<p><strong class="strong">Returns:</strong> On success, a pointer to an OID string, <code class="code">NULL</code>  on error.
</p>
<p><strong class="strong">Since:</strong> 3.5.5
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs7_005fget_005fsignature_005fcount-1"><span>gnutls_pkcs7_get_signature_count<a class="copiable-link" href="#gnutls_005fpkcs7_005fget_005fsignature_005fcount-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs7_005fget_005fsignature_005fcount"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs7_005fget_005fsignature_005fcount"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs7_get_signature_count</strong> <code class="def-code-arguments">(gnutls_pkcs7_t <var class="var">pkcs7</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs7_005fget_005fsignature_005fcount"> &para;</a></span></dt>
<dd><p><var class="var">pkcs7</var>: should contain a <code class="code">gnutls_pkcs7_t</code>  type
</p>
<p>This function will return the number of signatures in the PKCS7
structure.
</p>
<p><strong class="strong">Returns:</strong> On success, a positive number is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.4.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs7_005fget_005fsignature_005finfo-1"><span>gnutls_pkcs7_get_signature_info<a class="copiable-link" href="#gnutls_005fpkcs7_005fget_005fsignature_005finfo-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs7_005fget_005fsignature_005finfo"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs7_005fget_005fsignature_005finfo"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs7_get_signature_info</strong> <code class="def-code-arguments">(gnutls_pkcs7_t <var class="var">pkcs7</var>, unsigned <var class="var">idx</var>, gnutls_pkcs7_signature_info_st * <var class="var">info</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs7_005fget_005fsignature_005finfo"> &para;</a></span></dt>
<dd><p><var class="var">pkcs7</var>: should contain a <code class="code">gnutls_pkcs7_t</code>  type
</p>
<p><var class="var">idx</var>: the index of the signature info to check
</p>
<p><var class="var">info</var>: will contain the output signature
</p>
<p>This function will return information about the signature identified
by idx in the provided PKCS <code class="code">7</code>  structure. The information should be
deinitialized using <code class="code">gnutls_pkcs7_signature_info_deinit()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.4.2
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs7_005fimport-1"><span>gnutls_pkcs7_import<a class="copiable-link" href="#gnutls_005fpkcs7_005fimport-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs7_005fimport"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs7_005fimport"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs7_import</strong> <code class="def-code-arguments">(gnutls_pkcs7_t <var class="var">pkcs7</var>, const gnutls_datum_t * <var class="var">data</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs7_005fimport"> &para;</a></span></dt>
<dd><p><var class="var">pkcs7</var>: The data to store the parsed PKCS7.
</p>
<p><var class="var">data</var>: The DER or PEM encoded PKCS7.
</p>
<p><var class="var">format</var>: One of DER or PEM
</p>
<p>This function will convert the given DER or PEM encoded PKCS7 to
the native <code class="code">gnutls_pkcs7_t</code>  format.  The output will be stored in
 <code class="code">pkcs7</code> . Any signed data that may be present inside the  <code class="code">pkcs7</code> structure, like certificates set by <code class="code">gnutls_pkcs7_set_crt()</code> , will
be freed and overwritten by this function.
</p>
<p>If the PKCS7 is PEM encoded it should have a header of &quot;PKCS7&quot;.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs7_005finit-1"><span>gnutls_pkcs7_init<a class="copiable-link" href="#gnutls_005fpkcs7_005finit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs7_005finit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs7_005finit"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs7_init</strong> <code class="def-code-arguments">(gnutls_pkcs7_t * <var class="var">pkcs7</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs7_005finit"> &para;</a></span></dt>
<dd><p><var class="var">pkcs7</var>: A pointer to the type to be initialized
</p>
<p>This function will initialize a PKCS7 structure. PKCS7 structures
usually contain lists of X.509 Certificates and X.509 Certificate
revocation lists.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs7_005fprint-1"><span>gnutls_pkcs7_print<a class="copiable-link" href="#gnutls_005fpkcs7_005fprint-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs7_005fprint"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs7_005fprint"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs7_print</strong> <code class="def-code-arguments">(gnutls_pkcs7_t <var class="var">pkcs7</var>, gnutls_certificate_print_formats_t <var class="var">format</var>, gnutls_datum_t * <var class="var">out</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs7_005fprint"> &para;</a></span></dt>
<dd><p><var class="var">pkcs7</var>: The PKCS7 struct to be printed
</p>
<p><var class="var">format</var>: Indicate the format to use
</p>
<p><var class="var">out</var>: Newly allocated datum with null terminated string.
</p>
<p>This function will pretty print a signed PKCS <code class="code">7</code>  structure, suitable for
display to a human.
</p>
<p>Currently the supported formats are <code class="code">GNUTLS_CRT_PRINT_FULL</code>  and
<code class="code">GNUTLS_CRT_PRINT_COMPACT</code> .
</p>
<p>The output  <code class="code">out</code> needs to be deallocated using <code class="code">gnutls_free()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs7_005fprint_005fsignature_005finfo-1"><span>gnutls_pkcs7_print_signature_info<a class="copiable-link" href="#gnutls_005fpkcs7_005fprint_005fsignature_005finfo-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs7_005fprint_005fsignature_005finfo"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs7_005fprint_005fsignature_005finfo"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs7_print_signature_info</strong> <code class="def-code-arguments">(gnutls_pkcs7_signature_info_st * <var class="var">info</var>, gnutls_certificate_print_formats_t <var class="var">format</var>, gnutls_datum_t * <var class="var">out</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs7_005fprint_005fsignature_005finfo"> &para;</a></span></dt>
<dd><p><var class="var">info</var>: The PKCS7 signature info struct to be printed
</p>
<p><var class="var">format</var>: Indicate the format to use
</p>
<p><var class="var">out</var>: Newly allocated datum with null terminated string.
</p>
<p>This function will pretty print a PKCS <code class="code">7</code>  signature info structure, suitable
for display to a human.
</p>
<p>Currently the supported formats are <code class="code">GNUTLS_CRT_PRINT_FULL</code>  and
<code class="code">GNUTLS_CRT_PRINT_COMPACT</code> .
</p>
<p>The output  <code class="code">out</code> needs to be deallocated using <code class="code">gnutls_free()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.6.14
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs7_005fset_005fcrl-1"><span>gnutls_pkcs7_set_crl<a class="copiable-link" href="#gnutls_005fpkcs7_005fset_005fcrl-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs7_005fset_005fcrl"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs7_005fset_005fcrl"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs7_set_crl</strong> <code class="def-code-arguments">(gnutls_pkcs7_t <var class="var">pkcs7</var>, gnutls_x509_crl_t <var class="var">crl</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs7_005fset_005fcrl"> &para;</a></span></dt>
<dd><p><var class="var">pkcs7</var>: The pkcs7 type
</p>
<p><var class="var">crl</var>: the DER encoded crl to be added
</p>
<p>This function will add a parsed CRL to the PKCS7 or RFC2630 crl
set.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs7_005fset_005fcrl_005fraw-1"><span>gnutls_pkcs7_set_crl_raw<a class="copiable-link" href="#gnutls_005fpkcs7_005fset_005fcrl_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs7_005fset_005fcrl_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs7_005fset_005fcrl_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs7_set_crl_raw</strong> <code class="def-code-arguments">(gnutls_pkcs7_t <var class="var">pkcs7</var>, const gnutls_datum_t * <var class="var">crl</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs7_005fset_005fcrl_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">pkcs7</var>: The pkcs7 type
</p>
<p><var class="var">crl</var>: the DER encoded crl to be added
</p>
<p>This function will add a crl to the PKCS7 or RFC2630 crl set.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs7_005fset_005fcrt-1"><span>gnutls_pkcs7_set_crt<a class="copiable-link" href="#gnutls_005fpkcs7_005fset_005fcrt-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs7_005fset_005fcrt"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs7_005fset_005fcrt"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs7_set_crt</strong> <code class="def-code-arguments">(gnutls_pkcs7_t <var class="var">pkcs7</var>, gnutls_x509_crt_t <var class="var">crt</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs7_005fset_005fcrt"> &para;</a></span></dt>
<dd><p><var class="var">pkcs7</var>: The pkcs7 type
</p>
<p><var class="var">crt</var>: the certificate to be copied.
</p>
<p>This function will add a parsed certificate to the PKCS7 or
RFC2630 certificate set.  This is a wrapper function over
<code class="code">gnutls_pkcs7_set_crt_raw()</code>  .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs7_005fset_005fcrt_005fraw-1"><span>gnutls_pkcs7_set_crt_raw<a class="copiable-link" href="#gnutls_005fpkcs7_005fset_005fcrt_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs7_005fset_005fcrt_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs7_005fset_005fcrt_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs7_set_crt_raw</strong> <code class="def-code-arguments">(gnutls_pkcs7_t <var class="var">pkcs7</var>, const gnutls_datum_t * <var class="var">crt</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs7_005fset_005fcrt_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">pkcs7</var>: The pkcs7 type
</p>
<p><var class="var">crt</var>: the DER encoded certificate to be added
</p>
<p>This function will add a certificate to the PKCS7 or RFC2630
certificate set.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs7_005fsign-1"><span>gnutls_pkcs7_sign<a class="copiable-link" href="#gnutls_005fpkcs7_005fsign-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs7_005fsign"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs7_005fsign-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs7_sign</strong> <code class="def-code-arguments">(gnutls_pkcs7_t <var class="var">pkcs7</var>, gnutls_x509_crt_t <var class="var">signer</var>, gnutls_privkey_t <var class="var">signer_key</var>, const gnutls_datum_t * <var class="var">data</var>, gnutls_pkcs7_attrs_t <var class="var">signed_attrs</var>, gnutls_pkcs7_attrs_t <var class="var">unsigned_attrs</var>, gnutls_digest_algorithm_t <var class="var">dig</var>, unsigned <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs7_005fsign-1"> &para;</a></span></dt>
<dd><p><var class="var">pkcs7</var>: should contain a <code class="code">gnutls_pkcs7_t</code>  type
</p>
<p><var class="var">signer</var>: the certificate to sign the structure
</p>
<p><var class="var">signer_key</var>: the key to sign the structure
</p>
<p><var class="var">data</var>: The data to be signed or <code class="code">NULL</code>  if the data are already embedded
</p>
<p><var class="var">signed_attrs</var>: Any additional attributes to be included in the signed ones (or <code class="code">NULL</code> )
</p>
<p><var class="var">unsigned_attrs</var>: Any additional attributes to be included in the unsigned ones (or <code class="code">NULL</code> )
</p>
<p><var class="var">dig</var>: The digest algorithm to use for signing
</p>
<p><var class="var">flags</var>: Should be zero or one of <code class="code">GNUTLS_PKCS7</code>  flags
</p>
<p>This function will add a signature in the provided PKCS <code class="code">7</code>  structure
for the provided data. Multiple signatures can be made with different
signers.
</p>
<p>The available flags are:
<code class="code">GNUTLS_PKCS7_EMBED_DATA</code> , <code class="code">GNUTLS_PKCS7_INCLUDE_TIME</code> , <code class="code">GNUTLS_PKCS7_INCLUDE_CERT</code> ,
and <code class="code">GNUTLS_PKCS7_WRITE_SPKI</code> . They are explained in the <code class="code">gnutls_pkcs7_sign_flags</code> 
definition.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.4.2
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs7_005fsignature_005finfo_005fdeinit-1"><span>gnutls_pkcs7_signature_info_deinit<a class="copiable-link" href="#gnutls_005fpkcs7_005fsignature_005finfo_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs7_005fsignature_005finfo_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs7_005fsignature_005finfo_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_pkcs7_signature_info_deinit</strong> <code class="def-code-arguments">(gnutls_pkcs7_signature_info_st * <var class="var">info</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs7_005fsignature_005finfo_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">info</var>: should point to a <code class="code">gnutls_pkcs7_signature_info_st</code>  structure
</p>
<p>This function will deinitialize any allocated value in the
provided <code class="code">gnutls_pkcs7_signature_info_st</code> .
</p>
<p><strong class="strong">Since:</strong> 3.4.2
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs7_005fverify-1"><span>gnutls_pkcs7_verify<a class="copiable-link" href="#gnutls_005fpkcs7_005fverify-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs7_005fverify"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs7_005fverify"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs7_verify</strong> <code class="def-code-arguments">(gnutls_pkcs7_t <var class="var">pkcs7</var>, gnutls_x509_trust_list_t <var class="var">tl</var>, gnutls_typed_vdata_st * <var class="var">vdata</var>, unsigned int <var class="var">vdata_size</var>, unsigned <var class="var">idx</var>, const gnutls_datum_t * <var class="var">data</var>, unsigned <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs7_005fverify"> &para;</a></span></dt>
<dd><p><var class="var">pkcs7</var>: should contain a <code class="code">gnutls_pkcs7_t</code>  type
</p>
<p><var class="var">tl</var>: A list of trusted certificates
</p>
<p><var class="var">vdata</var>: an array of typed data
</p>
<p><var class="var">vdata_size</var>: the number of data elements
</p>
<p><var class="var">idx</var>: the index of the signature info to check
</p>
<p><var class="var">data</var>: The data to be verified or <code class="code">NULL</code> 
</p>
<p><var class="var">flags</var>: Zero or an OR list of <code class="code">gnutls_certificate_verify_flags</code> 
</p>
<p>This function will verify the provided data against the signature
present in the SignedData of the PKCS <code class="code">7</code>  structure. If the data
provided are NULL then the data in the encapsulatedContent field
will be used instead.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value. A verification error results to a
<code class="code">GNUTLS_E_PK_SIG_VERIFY_FAILED</code>  and the lack of encapsulated data
to verify to a <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> .
</p>
<p><strong class="strong">Since:</strong> 3.4.2
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs7_005fverify_005fdirect-1"><span>gnutls_pkcs7_verify_direct<a class="copiable-link" href="#gnutls_005fpkcs7_005fverify_005fdirect-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs7_005fverify_005fdirect"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs7_005fverify_005fdirect"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs7_verify_direct</strong> <code class="def-code-arguments">(gnutls_pkcs7_t <var class="var">pkcs7</var>, gnutls_x509_crt_t <var class="var">signer</var>, unsigned <var class="var">idx</var>, const gnutls_datum_t * <var class="var">data</var>, unsigned <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs7_005fverify_005fdirect"> &para;</a></span></dt>
<dd><p><var class="var">pkcs7</var>: should contain a <code class="code">gnutls_pkcs7_t</code>  type
</p>
<p><var class="var">signer</var>: the certificate believed to have signed the structure
</p>
<p><var class="var">idx</var>: the index of the signature info to check
</p>
<p><var class="var">data</var>: The data to be verified or <code class="code">NULL</code> 
</p>
<p><var class="var">flags</var>: Zero or an OR list of <code class="code">gnutls_certificate_verify_flags</code> 
</p>
<p>This function will verify the provided data against the signature
present in the SignedData of the PKCS <code class="code">7</code>  structure. If the data
provided are NULL then the data in the encapsulatedContent field
will be used instead.
</p>
<p>Note that, unlike <code class="code">gnutls_pkcs7_verify()</code>  this function does not
verify the key purpose of the signer. It is expected for the caller
to verify the intended purpose of the <code class="code">signer</code>  -e.g., via <code class="code">gnutls_x509_crt_get_key_purpose_oid()</code> ,
or <code class="code">gnutls_x509_crt_check_key_purpose()</code> .
</p>
<p>Note also, that since GnuTLS 3.5.6 this function introduces checks in the
end certificate ( <code class="code">signer</code> ), including time checks and key usage checks.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value. A verification error results to a
<code class="code">GNUTLS_E_PK_SIG_VERIFY_FAILED</code>  and the lack of encapsulated data
to verify to a <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> .
</p>
<p><strong class="strong">Since:</strong> 3.4.2
</p></dd></dl>


<hr>
</div>
<div class="section-level-extent" id="OCSP-API">
<div class="nav-panel">
<p>
Next: <a href="#PKCS-12-API" accesskey="n" rel="next">PKCS 12 API</a>, Previous: <a href="#PKCS-7-API" accesskey="p" rel="prev"><abbr class="acronym">PKCS</abbr> 7 API</a>, Up: <a href="#API-reference" accesskey="u" rel="up">API reference</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="OCSP-API-1"><span>E.5 <abbr class="acronym">OCSP</abbr> API<a class="copiable-link" href="#OCSP-API-1"> &para;</a></span></h3>
<a class="index-entry-id" id="index-OCSP-Functions"></a>

<p>The following functions are for <abbr class="acronym">OCSP</abbr> certificate status
checking.  Their prototypes lie in <samp class="file">gnutls/ocsp.h</samp>.
</p>

<h4 class="subheading" id="gnutls_005focsp_005freq_005fadd_005fcert-1"><span>gnutls_ocsp_req_add_cert<a class="copiable-link" href="#gnutls_005focsp_005freq_005fadd_005fcert-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005focsp_005freq_005fadd_005fcert"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005freq_005fadd_005fcert"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ocsp_req_add_cert</strong> <code class="def-code-arguments">(gnutls_ocsp_req_t <var class="var">req</var>, gnutls_digest_algorithm_t <var class="var">digest</var>, gnutls_x509_crt_t <var class="var">issuer</var>, gnutls_x509_crt_t <var class="var">cert</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005freq_005fadd_005fcert"> &para;</a></span></dt>
<dd><p><var class="var">req</var>: should contain a <code class="code">gnutls_ocsp_req_t</code>  type
</p>
<p><var class="var">digest</var>: hash algorithm, a <code class="code">gnutls_digest_algorithm_t</code>  value
</p>
<p><var class="var">issuer</var>: issuer of  <code class="code">subject</code> certificate
</p>
<p><var class="var">cert</var>: certificate to request status for
</p>
<p>This function will add another request to the OCSP request for a
particular certificate.  The issuer name hash, issuer key hash, and
serial number fields is populated as follows.  The issuer name and
the serial number is taken from  <code class="code">cert</code> .  The issuer key is taken
from  <code class="code">issuer</code> .  The hashed values will be hashed using the  <code class="code">digest</code> algorithm, normally <code class="code">GNUTLS_DIG_SHA1</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005focsp_005freq_005fadd_005fcert_005fid-1"><span>gnutls_ocsp_req_add_cert_id<a class="copiable-link" href="#gnutls_005focsp_005freq_005fadd_005fcert_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005focsp_005freq_005fadd_005fcert_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005freq_005fadd_005fcert_005fid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ocsp_req_add_cert_id</strong> <code class="def-code-arguments">(gnutls_ocsp_req_t <var class="var">req</var>, gnutls_digest_algorithm_t <var class="var">digest</var>, const gnutls_datum_t * <var class="var">issuer_name_hash</var>, const gnutls_datum_t * <var class="var">issuer_key_hash</var>, const gnutls_datum_t * <var class="var">serial_number</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005freq_005fadd_005fcert_005fid"> &para;</a></span></dt>
<dd><p><var class="var">req</var>: should contain a <code class="code">gnutls_ocsp_req_t</code>  type
</p>
<p><var class="var">digest</var>: hash algorithm, a <code class="code">gnutls_digest_algorithm_t</code>  value
</p>
<p><var class="var">issuer_name_hash</var>: hash of issuer&rsquo;s DN
</p>
<p><var class="var">issuer_key_hash</var>: hash of issuer&rsquo;s public key
</p>
<p><var class="var">serial_number</var>: serial number of certificate to check
</p>
<p>This function will add another request to the OCSP request for a
particular certificate having the issuer name hash of
 <code class="code">issuer_name_hash</code> and issuer key hash of  <code class="code">issuer_key_hash</code> (both
hashed using  <code class="code">digest</code> ) and serial number  <code class="code">serial_number</code> .
</p>
<p>The information needed corresponds to the CertID structure:
</p>
<p>&lt;informalexample&gt;&lt;programlisting&gt;
CertID	  ::=     SEQUENCE {
hashAlgorithm       AlgorithmIdentifier,
issuerNameHash      OCTET STRING, &ndash; Hash of Issuer&rsquo;s DN
issuerKeyHash       OCTET STRING, &ndash; Hash of Issuers public key
serialNumber	CertificateSerialNumber }
&lt;/programlisting&gt;&lt;/informalexample&gt;
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005focsp_005freq_005fdeinit-1"><span>gnutls_ocsp_req_deinit<a class="copiable-link" href="#gnutls_005focsp_005freq_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005focsp_005freq_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005freq_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_ocsp_req_deinit</strong> <code class="def-code-arguments">(gnutls_ocsp_req_t <var class="var">req</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005freq_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">req</var>: The data to be deinitialized
</p>
<p>This function will deinitialize a OCSP request structure.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005focsp_005freq_005fexport-1"><span>gnutls_ocsp_req_export<a class="copiable-link" href="#gnutls_005focsp_005freq_005fexport-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005focsp_005freq_005fexport"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005freq_005fexport"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ocsp_req_export</strong> <code class="def-code-arguments">(gnutls_ocsp_req_const_t <var class="var">req</var>, gnutls_datum_t * <var class="var">data</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005freq_005fexport"> &para;</a></span></dt>
<dd><p><var class="var">req</var>: Holds the OCSP request
</p>
<p><var class="var">data</var>: newly allocate buffer holding DER encoded OCSP request
</p>
<p>This function will export the OCSP request to DER format.
</p>
<p><strong class="strong">Returns:</strong> In case of failure a negative error code will be
returned, and 0 on success.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005focsp_005freq_005fget_005fcert_005fid-1"><span>gnutls_ocsp_req_get_cert_id<a class="copiable-link" href="#gnutls_005focsp_005freq_005fget_005fcert_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005focsp_005freq_005fget_005fcert_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005freq_005fget_005fcert_005fid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ocsp_req_get_cert_id</strong> <code class="def-code-arguments">(gnutls_ocsp_req_const_t <var class="var">req</var>, unsigned <var class="var">indx</var>, gnutls_digest_algorithm_t * <var class="var">digest</var>, gnutls_datum_t * <var class="var">issuer_name_hash</var>, gnutls_datum_t * <var class="var">issuer_key_hash</var>, gnutls_datum_t * <var class="var">serial_number</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005freq_005fget_005fcert_005fid"> &para;</a></span></dt>
<dd><p><var class="var">req</var>: should contain a <code class="code">gnutls_ocsp_req_t</code>  type
</p>
<p><var class="var">indx</var>: Specifies which extension OID to get. Use (0) to get the first one.
</p>
<p><var class="var">digest</var>: output variable with <code class="code">gnutls_digest_algorithm_t</code>  hash algorithm
</p>
<p><var class="var">issuer_name_hash</var>: output buffer with hash of issuer&rsquo;s DN
</p>
<p><var class="var">issuer_key_hash</var>: output buffer with hash of issuer&rsquo;s public key
</p>
<p><var class="var">serial_number</var>: output buffer with serial number of certificate to check
</p>
<p>This function will return the certificate information of the
 <code class="code">indx</code> &rsquo;ed request in the OCSP request.  The information returned
corresponds to the CertID structure:
</p>
<p>&lt;informalexample&gt;&lt;programlisting&gt;
CertID	  ::=     SEQUENCE {
hashAlgorithm       AlgorithmIdentifier,
issuerNameHash      OCTET STRING, &ndash; Hash of Issuer&rsquo;s DN
issuerKeyHash       OCTET STRING, &ndash; Hash of Issuers public key
serialNumber	CertificateSerialNumber }
&lt;/programlisting&gt;&lt;/informalexample&gt;
</p>
<p>Each of the pointers to output variables may be NULL to indicate
that the caller is not interested in that value.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error code is returned.  If you have reached the last
CertID available <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  will be
returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005focsp_005freq_005fget_005fextension-1"><span>gnutls_ocsp_req_get_extension<a class="copiable-link" href="#gnutls_005focsp_005freq_005fget_005fextension-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005focsp_005freq_005fget_005fextension"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005freq_005fget_005fextension"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ocsp_req_get_extension</strong> <code class="def-code-arguments">(gnutls_ocsp_req_const_t <var class="var">req</var>, unsigned <var class="var">indx</var>, gnutls_datum_t * <var class="var">oid</var>, unsigned int * <var class="var">critical</var>, gnutls_datum_t * <var class="var">data</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005freq_005fget_005fextension"> &para;</a></span></dt>
<dd><p><var class="var">req</var>: should contain a <code class="code">gnutls_ocsp_req_t</code>  type
</p>
<p><var class="var">indx</var>: Specifies which extension OID to get. Use (0) to get the first one.
</p>
<p><var class="var">oid</var>: will hold newly allocated buffer with OID of extension, may be NULL
</p>
<p><var class="var">critical</var>: output variable with critical flag, may be NULL.
</p>
<p><var class="var">data</var>: will hold newly allocated buffer with extension data, may be NULL
</p>
<p>This function will return all information about the requested
extension in the OCSP request.  The information returned is the
OID, the critical flag, and the data itself.  The extension OID
will be stored as a string.  Any of  <code class="code">oid</code> ,  <code class="code">critical</code> , and  <code class="code">data</code> may
be NULL which means that the caller is not interested in getting
that information back.
</p>
<p>The caller needs to deallocate memory by calling <code class="code">gnutls_free()</code>  on
 <code class="code">oid</code> -&gt;data and  <code class="code">data</code> -&gt;data.
</p>
<p>Since 3.7.0  <code class="code">oid</code> -&gt;size does not account for the terminating null byte.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error code is returned.  If you have reached the last
extension available <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  will
be returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005focsp_005freq_005fget_005fnonce-1"><span>gnutls_ocsp_req_get_nonce<a class="copiable-link" href="#gnutls_005focsp_005freq_005fget_005fnonce-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005focsp_005freq_005fget_005fnonce"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005freq_005fget_005fnonce"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ocsp_req_get_nonce</strong> <code class="def-code-arguments">(gnutls_ocsp_req_const_t <var class="var">req</var>, unsigned int * <var class="var">critical</var>, gnutls_datum_t * <var class="var">nonce</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005freq_005fget_005fnonce"> &para;</a></span></dt>
<dd><p><var class="var">req</var>: should contain a <code class="code">gnutls_ocsp_req_t</code>  type
</p>
<p><var class="var">critical</var>: whether nonce extension is marked critical, or NULL
</p>
<p><var class="var">nonce</var>: will hold newly allocated buffer with nonce data
</p>
<p>This function will return the OCSP request nonce extension data.
</p>
<p>The caller needs to deallocate memory by calling <code class="code">gnutls_free()</code>  on
 <code class="code">nonce</code> -&gt;data.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005focsp_005freq_005fget_005fversion-1"><span>gnutls_ocsp_req_get_version<a class="copiable-link" href="#gnutls_005focsp_005freq_005fget_005fversion-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005focsp_005freq_005fget_005fversion"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005freq_005fget_005fversion"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ocsp_req_get_version</strong> <code class="def-code-arguments">(gnutls_ocsp_req_const_t <var class="var">req</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005freq_005fget_005fversion"> &para;</a></span></dt>
<dd><p><var class="var">req</var>: should contain a <code class="code">gnutls_ocsp_req_t</code>  type
</p>
<p>This function will return the version of the OCSP request.
Typically this is always 1 indicating version 1.
</p>
<p><strong class="strong">Returns:</strong> version of OCSP request, or a negative error code on error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005focsp_005freq_005fimport-1"><span>gnutls_ocsp_req_import<a class="copiable-link" href="#gnutls_005focsp_005freq_005fimport-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005focsp_005freq_005fimport"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005freq_005fimport"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ocsp_req_import</strong> <code class="def-code-arguments">(gnutls_ocsp_req_t <var class="var">req</var>, const gnutls_datum_t * <var class="var">data</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005freq_005fimport"> &para;</a></span></dt>
<dd><p><var class="var">req</var>: The data to store the parsed request.
</p>
<p><var class="var">data</var>: DER encoded OCSP request.
</p>
<p>This function will convert the given DER encoded OCSP request to
the native <code class="code">gnutls_ocsp_req_t</code>  format. The output will be stored in
 <code class="code">req</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005focsp_005freq_005finit-1"><span>gnutls_ocsp_req_init<a class="copiable-link" href="#gnutls_005focsp_005freq_005finit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005focsp_005freq_005finit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005freq_005finit"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ocsp_req_init</strong> <code class="def-code-arguments">(gnutls_ocsp_req_t * <var class="var">req</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005freq_005finit"> &para;</a></span></dt>
<dd><p><var class="var">req</var>: A pointer to the type to be initialized
</p>
<p>This function will initialize an OCSP request structure.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005focsp_005freq_005fprint-1"><span>gnutls_ocsp_req_print<a class="copiable-link" href="#gnutls_005focsp_005freq_005fprint-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005focsp_005freq_005fprint"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005freq_005fprint"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ocsp_req_print</strong> <code class="def-code-arguments">(gnutls_ocsp_req_const_t <var class="var">req</var>, gnutls_ocsp_print_formats_t <var class="var">format</var>, gnutls_datum_t * <var class="var">out</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005freq_005fprint"> &para;</a></span></dt>
<dd><p><var class="var">req</var>: The data to be printed
</p>
<p><var class="var">format</var>: Indicate the format to use
</p>
<p><var class="var">out</var>: Newly allocated datum with (0) terminated string.
</p>
<p>This function will pretty print a OCSP request, suitable for
display to a human.
</p>
<p>If the format is <code class="code">GNUTLS_OCSP_PRINT_FULL</code>  then all fields of the
request will be output, on multiple lines.
</p>
<p>The output  <code class="code">out</code> -&gt;data needs to be deallocate using <code class="code">gnutls_free()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005focsp_005freq_005frandomize_005fnonce-1"><span>gnutls_ocsp_req_randomize_nonce<a class="copiable-link" href="#gnutls_005focsp_005freq_005frandomize_005fnonce-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005focsp_005freq_005frandomize_005fnonce"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005freq_005frandomize_005fnonce"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ocsp_req_randomize_nonce</strong> <code class="def-code-arguments">(gnutls_ocsp_req_t <var class="var">req</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005freq_005frandomize_005fnonce"> &para;</a></span></dt>
<dd><p><var class="var">req</var>: should contain a <code class="code">gnutls_ocsp_req_t</code>  type
</p>
<p>This function will add or update an nonce extension to the OCSP
request with a newly generated random value.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005focsp_005freq_005fset_005fextension-1"><span>gnutls_ocsp_req_set_extension<a class="copiable-link" href="#gnutls_005focsp_005freq_005fset_005fextension-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005focsp_005freq_005fset_005fextension"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005freq_005fset_005fextension"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ocsp_req_set_extension</strong> <code class="def-code-arguments">(gnutls_ocsp_req_t <var class="var">req</var>, const char * <var class="var">oid</var>, unsigned int <var class="var">critical</var>, const gnutls_datum_t * <var class="var">data</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005freq_005fset_005fextension"> &para;</a></span></dt>
<dd><p><var class="var">req</var>: should contain a <code class="code">gnutls_ocsp_req_t</code>  type
</p>
<p><var class="var">oid</var>: buffer with OID of extension as a string.
</p>
<p><var class="var">critical</var>: critical flag, normally false.
</p>
<p><var class="var">data</var>: the extension data
</p>
<p>This function will add an extension to the OCSP request.  Calling
this function multiple times for the same OID will overwrite values
from earlier calls.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005focsp_005freq_005fset_005fnonce-1"><span>gnutls_ocsp_req_set_nonce<a class="copiable-link" href="#gnutls_005focsp_005freq_005fset_005fnonce-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005focsp_005freq_005fset_005fnonce"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005freq_005fset_005fnonce"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ocsp_req_set_nonce</strong> <code class="def-code-arguments">(gnutls_ocsp_req_t <var class="var">req</var>, unsigned int <var class="var">critical</var>, const gnutls_datum_t * <var class="var">nonce</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005freq_005fset_005fnonce"> &para;</a></span></dt>
<dd><p><var class="var">req</var>: should contain a <code class="code">gnutls_ocsp_req_t</code>  type
</p>
<p><var class="var">critical</var>: critical flag, normally false.
</p>
<p><var class="var">nonce</var>: the nonce data
</p>
<p>This function will add an nonce extension to the OCSP request.
Calling this function multiple times will overwrite values from
earlier calls.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005focsp_005fresp_005fcheck_005fcrt-1"><span>gnutls_ocsp_resp_check_crt<a class="copiable-link" href="#gnutls_005focsp_005fresp_005fcheck_005fcrt-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005focsp_005fresp_005fcheck_005fcrt"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005fresp_005fcheck_005fcrt"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ocsp_resp_check_crt</strong> <code class="def-code-arguments">(gnutls_ocsp_resp_const_t <var class="var">resp</var>, unsigned int <var class="var">indx</var>, gnutls_x509_crt_t <var class="var">crt</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005fresp_005fcheck_005fcrt"> &para;</a></span></dt>
<dd><p><var class="var">resp</var>: should contain a <code class="code">gnutls_ocsp_resp_t</code>  type
</p>
<p><var class="var">indx</var>: Specifies response number to get. Use (0) to get the first one.
</p>
<p><var class="var">crt</var>: The certificate to check
</p>
<p>This function will check whether the OCSP response
is about the provided certificate.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error code is returned.  
</p>
<p><strong class="strong">Since:</strong> 3.1.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005focsp_005fresp_005fdeinit-1"><span>gnutls_ocsp_resp_deinit<a class="copiable-link" href="#gnutls_005focsp_005fresp_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005focsp_005fresp_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005fresp_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_ocsp_resp_deinit</strong> <code class="def-code-arguments">(gnutls_ocsp_resp_t <var class="var">resp</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005fresp_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">resp</var>: The data to be deinitialized
</p>
<p>This function will deinitialize a OCSP response structure.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005focsp_005fresp_005fexport-1"><span>gnutls_ocsp_resp_export<a class="copiable-link" href="#gnutls_005focsp_005fresp_005fexport-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005focsp_005fresp_005fexport"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005fresp_005fexport"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ocsp_resp_export</strong> <code class="def-code-arguments">(gnutls_ocsp_resp_const_t <var class="var">resp</var>, gnutls_datum_t * <var class="var">data</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005fresp_005fexport"> &para;</a></span></dt>
<dd><p><var class="var">resp</var>: Holds the OCSP response
</p>
<p><var class="var">data</var>: newly allocate buffer holding DER encoded OCSP response
</p>
<p>This function will export the OCSP response to DER format.
</p>
<p><strong class="strong">Returns:</strong> In case of failure a negative error code will be
returned, and 0 on success.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005focsp_005fresp_005fexport2-1"><span>gnutls_ocsp_resp_export2<a class="copiable-link" href="#gnutls_005focsp_005fresp_005fexport2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005focsp_005fresp_005fexport2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005fresp_005fexport2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ocsp_resp_export2</strong> <code class="def-code-arguments">(gnutls_ocsp_resp_const_t <var class="var">resp</var>, gnutls_datum_t * <var class="var">data</var>, gnutls_x509_crt_fmt_t <var class="var">fmt</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005fresp_005fexport2"> &para;</a></span></dt>
<dd><p><var class="var">resp</var>: Holds the OCSP response
</p>
<p><var class="var">data</var>: newly allocate buffer holding DER or PEM encoded OCSP response
</p>
<p><var class="var">fmt</var>: DER or PEM
</p>
<p>This function will export the OCSP response to DER or PEM format.
</p>
<p><strong class="strong">Returns:</strong> In case of failure a negative error code will be
returned, and 0 on success.
</p>
<p><strong class="strong">Since:</strong> 3.6.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005focsp_005fresp_005fget_005fcerts-1"><span>gnutls_ocsp_resp_get_certs<a class="copiable-link" href="#gnutls_005focsp_005fresp_005fget_005fcerts-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005focsp_005fresp_005fget_005fcerts"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005fresp_005fget_005fcerts"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ocsp_resp_get_certs</strong> <code class="def-code-arguments">(gnutls_ocsp_resp_const_t <var class="var">resp</var>, gnutls_x509_crt_t ** <var class="var">certs</var>, size_t * <var class="var">ncerts</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005fresp_005fget_005fcerts"> &para;</a></span></dt>
<dd><p><var class="var">resp</var>: should contain a <code class="code">gnutls_ocsp_resp_t</code>  type
</p>
<p><var class="var">certs</var>: newly allocated array with <code class="code">gnutls_x509_crt_t</code>  certificates
</p>
<p><var class="var">ncerts</var>: output variable with number of allocated certs.
</p>
<p>This function will extract the X.509 certificates found in the
Basic OCSP Response.  The  <code class="code">certs</code> output variable will hold a newly
allocated zero-terminated array with X.509 certificates.
</p>
<p>Every certificate in the array needs to be de-allocated with
<code class="code">gnutls_x509_crt_deinit()</code>  and the array itself must be freed using
<code class="code">gnutls_free()</code> .
</p>
<p>Both the  <code class="code">certs</code> and  <code class="code">ncerts</code> variables may be NULL.  Then the
function will work as normal but will not return the NULL:d
information.  This can be used to get the number of certificates
only, or to just get the certificate array without its size.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005focsp_005fresp_005fget_005fextension-1"><span>gnutls_ocsp_resp_get_extension<a class="copiable-link" href="#gnutls_005focsp_005fresp_005fget_005fextension-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005focsp_005fresp_005fget_005fextension"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005fresp_005fget_005fextension"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ocsp_resp_get_extension</strong> <code class="def-code-arguments">(gnutls_ocsp_resp_const_t <var class="var">resp</var>, unsigned <var class="var">indx</var>, gnutls_datum_t * <var class="var">oid</var>, unsigned int * <var class="var">critical</var>, gnutls_datum_t * <var class="var">data</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005fresp_005fget_005fextension"> &para;</a></span></dt>
<dd><p><var class="var">resp</var>: should contain a <code class="code">gnutls_ocsp_resp_t</code>  type
</p>
<p><var class="var">indx</var>: Specifies which extension OID to get. Use (0) to get the first one.
</p>
<p><var class="var">oid</var>: will hold newly allocated buffer with OID of extension, may be NULL
</p>
<p><var class="var">critical</var>: output variable with critical flag, may be NULL.
</p>
<p><var class="var">data</var>: will hold newly allocated buffer with extension data, may be NULL
</p>
<p>This function will return all information about the requested
extension in the OCSP response.  The information returned is the
OID, the critical flag, and the data itself.  The extension OID
will be stored as a string.  Any of  <code class="code">oid</code> ,  <code class="code">critical</code> , and  <code class="code">data</code> may
be NULL which means that the caller is not interested in getting
that information back.
</p>
<p>The caller needs to deallocate memory by calling <code class="code">gnutls_free()</code>  on
 <code class="code">oid</code> -&gt;data and  <code class="code">data</code> -&gt;data.
</p>
<p>Since 3.7.0  <code class="code">oid</code> -&gt;size does not account for the terminating null byte.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error code is returned.  If you have reached the last
extension available <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  will
be returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005focsp_005fresp_005fget_005fnonce-1"><span>gnutls_ocsp_resp_get_nonce<a class="copiable-link" href="#gnutls_005focsp_005fresp_005fget_005fnonce-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005focsp_005fresp_005fget_005fnonce"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005fresp_005fget_005fnonce"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ocsp_resp_get_nonce</strong> <code class="def-code-arguments">(gnutls_ocsp_resp_const_t <var class="var">resp</var>, unsigned int * <var class="var">critical</var>, gnutls_datum_t * <var class="var">nonce</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005fresp_005fget_005fnonce"> &para;</a></span></dt>
<dd><p><var class="var">resp</var>: should contain a <code class="code">gnutls_ocsp_resp_t</code>  type
</p>
<p><var class="var">critical</var>: whether nonce extension is marked critical
</p>
<p><var class="var">nonce</var>: will hold newly allocated buffer with nonce data
</p>
<p>This function will return the Basic OCSP Response nonce extension
data.
</p>
<p>The caller needs to deallocate memory by calling <code class="code">gnutls_free()</code>  on
 <code class="code">nonce</code> -&gt;data.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005focsp_005fresp_005fget_005fproduced-1"><span>gnutls_ocsp_resp_get_produced<a class="copiable-link" href="#gnutls_005focsp_005fresp_005fget_005fproduced-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005focsp_005fresp_005fget_005fproduced"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005fresp_005fget_005fproduced"><span class="category-def">Function: </span><span><code class="def-type">time_t</code> <strong class="def-name">gnutls_ocsp_resp_get_produced</strong> <code class="def-code-arguments">(gnutls_ocsp_resp_const_t <var class="var">resp</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005fresp_005fget_005fproduced"> &para;</a></span></dt>
<dd><p><var class="var">resp</var>: should contain a <code class="code">gnutls_ocsp_resp_t</code>  type
</p>
<p>This function will return the time when the OCSP response was
signed.
</p>
<p><strong class="strong">Returns:</strong> signing time, or (time_t)-1 on error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005focsp_005fresp_005fget_005fresponder-1"><span>gnutls_ocsp_resp_get_responder<a class="copiable-link" href="#gnutls_005focsp_005fresp_005fget_005fresponder-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005focsp_005fresp_005fget_005fresponder"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005fresp_005fget_005fresponder"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ocsp_resp_get_responder</strong> <code class="def-code-arguments">(gnutls_ocsp_resp_const_t <var class="var">resp</var>, gnutls_datum_t * <var class="var">dn</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005fresp_005fget_005fresponder"> &para;</a></span></dt>
<dd><p><var class="var">resp</var>: should contain a <code class="code">gnutls_ocsp_resp_t</code>  type
</p>
<p><var class="var">dn</var>: newly allocated buffer with name
</p>
<p>This function will extract the name of the Basic OCSP Response in
the provided buffer. The name will be in the form
&quot;C=xxxx,O=yyyy,CN=zzzz&quot; as described in RFC2253. The output string
will be ASCII or UTF-8 encoded, depending on the certificate data.
</p>
<p>If the responder ID is not a name but a hash, this function
will return zero and the  <code class="code">dn</code> elements will be set to <code class="code">NULL</code> .
</p>
<p>The caller needs to deallocate memory by calling <code class="code">gnutls_free()</code>  on
 <code class="code">dn</code> -&gt;data.
</p>
<p>This function does not output a fully RFC4514 compliant string, if
that is required see <code class="code">gnutls_ocsp_resp_get_responder2()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error code is returned. When no data exist it will
return success and set  <code class="code">dn</code> elements to zero.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005focsp_005fresp_005fget_005fresponder2-1"><span>gnutls_ocsp_resp_get_responder2<a class="copiable-link" href="#gnutls_005focsp_005fresp_005fget_005fresponder2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005focsp_005fresp_005fget_005fresponder2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005fresp_005fget_005fresponder2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ocsp_resp_get_responder2</strong> <code class="def-code-arguments">(gnutls_ocsp_resp_const_t <var class="var">resp</var>, gnutls_datum_t * <var class="var">dn</var>, unsigned <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005fresp_005fget_005fresponder2"> &para;</a></span></dt>
<dd><p><var class="var">resp</var>: should contain a <code class="code">gnutls_ocsp_resp_t</code>  type
</p>
<p><var class="var">dn</var>: newly allocated buffer with name
</p>
<p><var class="var">flags</var>: zero or <code class="code">GNUTLS_X509_DN_FLAG_COMPAT</code> 
</p>
<p>This function will extract the name of the Basic OCSP Response in
the provided buffer. The name will be in the form
&quot;C=xxxx,O=yyyy,CN=zzzz&quot; as described in RFC2253. The output string
will be ASCII or UTF-8 encoded, depending on the certificate data.
</p>
<p>If the responder ID is not a name but a hash, this function
will return zero and the  <code class="code">dn</code> elements will be set to <code class="code">NULL</code> .
</p>
<p>The caller needs to deallocate memory by calling <code class="code">gnutls_free()</code>  on
 <code class="code">dn</code> -&gt;data.
</p>
<p>When the flag <code class="code">GNUTLS_X509_DN_FLAG_COMPAT</code>  is specified, the output
format will match the format output by previous to 3.5.6 versions of GnuTLS
which was not not fully RFC4514-compliant.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error code is returned. When no data exist it will return
<code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> .
</p></dd></dl>

<h4 class="subheading" id="gnutls_005focsp_005fresp_005fget_005fresponder_005fraw_005fid-1"><span>gnutls_ocsp_resp_get_responder_raw_id<a class="copiable-link" href="#gnutls_005focsp_005fresp_005fget_005fresponder_005fraw_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005focsp_005fresp_005fget_005fresponder_005fraw_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005fresp_005fget_005fresponder_005fraw_005fid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ocsp_resp_get_responder_raw_id</strong> <code class="def-code-arguments">(gnutls_ocsp_resp_const_t <var class="var">resp</var>, unsigned <var class="var">type</var>, gnutls_datum_t * <var class="var">raw</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005fresp_005fget_005fresponder_005fraw_005fid"> &para;</a></span></dt>
<dd><p><var class="var">resp</var>: should contain a <code class="code">gnutls_ocsp_resp_t</code>  type
</p>
<p><var class="var">type</var>: should be <code class="code">GNUTLS_OCSP_RESP_ID_KEY</code>  or <code class="code">GNUTLS_OCSP_RESP_ID_DN</code> 
</p>
<p><var class="var">raw</var>: newly allocated buffer with the raw ID
</p>
<p>This function will extract the raw key (or DN) ID of the Basic OCSP Response in
the provided buffer. If the responder ID is not a key ID then
this function will return <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> .
</p>
<p>The caller needs to deallocate memory by calling <code class="code">gnutls_free()</code>  on
 <code class="code">dn</code> -&gt;data.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005focsp_005fresp_005fget_005fresponse-1"><span>gnutls_ocsp_resp_get_response<a class="copiable-link" href="#gnutls_005focsp_005fresp_005fget_005fresponse-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005focsp_005fresp_005fget_005fresponse"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005fresp_005fget_005fresponse"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ocsp_resp_get_response</strong> <code class="def-code-arguments">(gnutls_ocsp_resp_const_t <var class="var">resp</var>, gnutls_datum_t * <var class="var">response_type_oid</var>, gnutls_datum_t * <var class="var">response</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005fresp_005fget_005fresponse"> &para;</a></span></dt>
<dd><p><var class="var">resp</var>: should contain a <code class="code">gnutls_ocsp_resp_t</code>  type
</p>
<p><var class="var">response_type_oid</var>: newly allocated output buffer with response type OID
</p>
<p><var class="var">response</var>: newly allocated output buffer with DER encoded response
</p>
<p>This function will extract the response type OID in and the
response data from an OCSP response.  Normally the
 <code class="code">response_type_oid</code> is always &quot;1.3.6.1.5.5.7.48.1.1&quot; which means the
 <code class="code">response</code> should be decoded as a Basic OCSP Response, but
technically other response types could be used.
</p>
<p>This function is typically only useful when you want to extract the
response type OID of an response for diagnostic purposes.
Otherwise <code class="code">gnutls_ocsp_resp_import()</code>  will decode the basic OCSP
response part and the caller need not worry about that aspect.
</p>
<p>Since 3.7.0  <code class="code">response_type_oid</code> -&gt;size does not account for the terminating
null byte.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005focsp_005fresp_005fget_005fsignature-1"><span>gnutls_ocsp_resp_get_signature<a class="copiable-link" href="#gnutls_005focsp_005fresp_005fget_005fsignature-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005focsp_005fresp_005fget_005fsignature"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005fresp_005fget_005fsignature"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ocsp_resp_get_signature</strong> <code class="def-code-arguments">(gnutls_ocsp_resp_const_t <var class="var">resp</var>, gnutls_datum_t * <var class="var">sig</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005fresp_005fget_005fsignature"> &para;</a></span></dt>
<dd><p><var class="var">resp</var>: should contain a <code class="code">gnutls_ocsp_resp_t</code>  type
</p>
<p><var class="var">sig</var>: newly allocated output buffer with signature data
</p>
<p>This function will extract the signature field of a OCSP response.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005focsp_005fresp_005fget_005fsignature_005falgorithm-1"><span>gnutls_ocsp_resp_get_signature_algorithm<a class="copiable-link" href="#gnutls_005focsp_005fresp_005fget_005fsignature_005falgorithm-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005focsp_005fresp_005fget_005fsignature_005falgorithm"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005fresp_005fget_005fsignature_005falgorithm"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ocsp_resp_get_signature_algorithm</strong> <code class="def-code-arguments">(gnutls_ocsp_resp_const_t <var class="var">resp</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005fresp_005fget_005fsignature_005falgorithm"> &para;</a></span></dt>
<dd><p><var class="var">resp</var>: should contain a <code class="code">gnutls_ocsp_resp_t</code>  type
</p>
<p>This function will return a value of the <code class="code">gnutls_sign_algorithm_t</code> 
enumeration that is the signature algorithm that has been used to
sign the OCSP response.
</p>
<p><strong class="strong">Returns:</strong> a <code class="code">gnutls_sign_algorithm_t</code>  value, or a negative error code
on error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005focsp_005fresp_005fget_005fsingle-1"><span>gnutls_ocsp_resp_get_single<a class="copiable-link" href="#gnutls_005focsp_005fresp_005fget_005fsingle-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005focsp_005fresp_005fget_005fsingle"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005fresp_005fget_005fsingle-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ocsp_resp_get_single</strong> <code class="def-code-arguments">(gnutls_ocsp_resp_const_t <var class="var">resp</var>, unsigned <var class="var">indx</var>, gnutls_digest_algorithm_t * <var class="var">digest</var>, gnutls_datum_t * <var class="var">issuer_name_hash</var>, gnutls_datum_t * <var class="var">issuer_key_hash</var>, gnutls_datum_t * <var class="var">serial_number</var>, unsigned int * <var class="var">cert_status</var>, time_t * <var class="var">this_update</var>, time_t * <var class="var">next_update</var>, time_t * <var class="var">revocation_time</var>, unsigned int * <var class="var">revocation_reason</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005fresp_005fget_005fsingle-1"> &para;</a></span></dt>
<dd><p><var class="var">resp</var>: should contain a <code class="code">gnutls_ocsp_resp_t</code>  type
</p>
<p><var class="var">indx</var>: Specifies response number to get. Use (0) to get the first one.
</p>
<p><var class="var">digest</var>: output variable with <code class="code">gnutls_digest_algorithm_t</code>  hash algorithm
</p>
<p><var class="var">issuer_name_hash</var>: output buffer with hash of issuer&rsquo;s DN
</p>
<p><var class="var">issuer_key_hash</var>: output buffer with hash of issuer&rsquo;s public key
</p>
<p><var class="var">serial_number</var>: output buffer with serial number of certificate to check
</p>
<p><var class="var">cert_status</var>: a certificate status, a <code class="code">gnutls_ocsp_cert_status_t</code>  enum.
</p>
<p><var class="var">this_update</var>: time at which the status is known to be correct.
</p>
<p><var class="var">next_update</var>: when newer information will be available, or (time_t)-1 if unspecified
</p>
<p><var class="var">revocation_time</var>: when  <code class="code">cert_status</code> is <code class="code">GNUTLS_OCSP_CERT_REVOKED</code> , holds time of revocation.
</p>
<p><var class="var">revocation_reason</var>: revocation reason, a <code class="code">gnutls_x509_crl_reason_t</code>  enum.
</p>
<p>This function will return the certificate information of the
 <code class="code">indx</code> &rsquo;ed response in the Basic OCSP Response  <code class="code">resp</code> .  The
information returned corresponds to the OCSP SingleResponse structure
except the final singleExtensions.
</p>
<p>Each of the pointers to output variables may be NULL to indicate
that the caller is not interested in that value.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error code is returned.  If you have reached the last
CertID available <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  will be
returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005focsp_005fresp_005fget_005fstatus-1"><span>gnutls_ocsp_resp_get_status<a class="copiable-link" href="#gnutls_005focsp_005fresp_005fget_005fstatus-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005focsp_005fresp_005fget_005fstatus"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005fresp_005fget_005fstatus"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ocsp_resp_get_status</strong> <code class="def-code-arguments">(gnutls_ocsp_resp_const_t <var class="var">resp</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005fresp_005fget_005fstatus"> &para;</a></span></dt>
<dd><p><var class="var">resp</var>: should contain a <code class="code">gnutls_ocsp_resp_t</code>  type
</p>
<p>This function will return the status of a OCSP response, an
<code class="code">gnutls_ocsp_resp_status_t</code>  enumeration.
</p>
<p><strong class="strong">Returns:</strong> status of OCSP request as a <code class="code">gnutls_ocsp_resp_status_t</code> , or
a negative error code on error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005focsp_005fresp_005fget_005fversion-1"><span>gnutls_ocsp_resp_get_version<a class="copiable-link" href="#gnutls_005focsp_005fresp_005fget_005fversion-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005focsp_005fresp_005fget_005fversion"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005fresp_005fget_005fversion"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ocsp_resp_get_version</strong> <code class="def-code-arguments">(gnutls_ocsp_resp_const_t <var class="var">resp</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005fresp_005fget_005fversion"> &para;</a></span></dt>
<dd><p><var class="var">resp</var>: should contain a <code class="code">gnutls_ocsp_resp_t</code>  type
</p>
<p>This function will return the version of the Basic OCSP Response.
Typically this is always 1 indicating version 1.
</p>
<p><strong class="strong">Returns:</strong> version of Basic OCSP response, or a negative error code
on error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005focsp_005fresp_005fimport-1"><span>gnutls_ocsp_resp_import<a class="copiable-link" href="#gnutls_005focsp_005fresp_005fimport-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005focsp_005fresp_005fimport"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005fresp_005fimport"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ocsp_resp_import</strong> <code class="def-code-arguments">(gnutls_ocsp_resp_t <var class="var">resp</var>, const gnutls_datum_t * <var class="var">data</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005fresp_005fimport"> &para;</a></span></dt>
<dd><p><var class="var">resp</var>: The data to store the parsed response.
</p>
<p><var class="var">data</var>: DER encoded OCSP response.
</p>
<p>This function will convert the given DER encoded OCSP response to
the native <code class="code">gnutls_ocsp_resp_t</code>  format.  It also decodes the Basic
OCSP Response part, if any.  The output will be stored in  <code class="code">resp</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005focsp_005fresp_005fimport2-1"><span>gnutls_ocsp_resp_import2<a class="copiable-link" href="#gnutls_005focsp_005fresp_005fimport2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005focsp_005fresp_005fimport2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005fresp_005fimport2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ocsp_resp_import2</strong> <code class="def-code-arguments">(gnutls_ocsp_resp_t <var class="var">resp</var>, const gnutls_datum_t * <var class="var">data</var>, gnutls_x509_crt_fmt_t <var class="var">fmt</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005fresp_005fimport2"> &para;</a></span></dt>
<dd><p><var class="var">resp</var>: The data to store the parsed response.
</p>
<p><var class="var">data</var>: DER or PEM encoded OCSP response.
</p>
<p><var class="var">fmt</var>: DER or PEM
</p>
<p>This function will convert the given OCSP response to
the native <code class="code">gnutls_ocsp_resp_t</code>  format.  It also decodes the Basic
OCSP Response part, if any.  The output will be stored in  <code class="code">resp</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.6.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005focsp_005fresp_005finit-1"><span>gnutls_ocsp_resp_init<a class="copiable-link" href="#gnutls_005focsp_005fresp_005finit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005focsp_005fresp_005finit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005fresp_005finit"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ocsp_resp_init</strong> <code class="def-code-arguments">(gnutls_ocsp_resp_t * <var class="var">resp</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005fresp_005finit"> &para;</a></span></dt>
<dd><p><var class="var">resp</var>: A pointer to the type to be initialized
</p>
<p>This function will initialize an OCSP response structure.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005focsp_005fresp_005flist_005fimport2-1"><span>gnutls_ocsp_resp_list_import2<a class="copiable-link" href="#gnutls_005focsp_005fresp_005flist_005fimport2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005focsp_005fresp_005flist_005fimport2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005fresp_005flist_005fimport2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ocsp_resp_list_import2</strong> <code class="def-code-arguments">(gnutls_ocsp_resp_t ** <var class="var">ocsps</var>, unsigned int * <var class="var">size</var>, const gnutls_datum_t * <var class="var">resp_data</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005fresp_005flist_005fimport2"> &para;</a></span></dt>
<dd><p><var class="var">ocsps</var>: Will hold the parsed OCSP response list.
</p>
<p><var class="var">size</var>: It will contain the size of the list.
</p>
<p><var class="var">resp_data</var>: The PEM encoded OCSP list.
</p>
<p><var class="var">format</var>: One of <code class="code">GNUTLS_X509_FMT_PEM</code>  or <code class="code">GNUTLS_X509_FMT_DER</code> 
</p>
<p><var class="var">flags</var>: must be (0) or an OR&rsquo;d sequence of gnutls_certificate_import_flags.
</p>
<p>This function will convert the given PEM encoded OCSP response list
to the native gnutls_ocsp_resp_t format. The output will be stored
in  <code class="code">ocsps</code> which will be allocated and initialized.
</p>
<p>The OCSP responses should have a header of &quot;OCSP RESPONSE&quot;.
</p>
<p>To deinitialize responses, you need to deinitialize each <code class="code">gnutls_ocsp_resp_t</code> 
structure independently, and use <code class="code">gnutls_free()</code>  at  <code class="code">ocsps</code> .
</p>
<p>In PEM files, when no OCSP responses are detected
<code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  will be returned.
</p>
<p><strong class="strong">Returns:</strong> the number of responses read or a negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.6.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005focsp_005fresp_005fprint-1"><span>gnutls_ocsp_resp_print<a class="copiable-link" href="#gnutls_005focsp_005fresp_005fprint-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005focsp_005fresp_005fprint"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005fresp_005fprint"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ocsp_resp_print</strong> <code class="def-code-arguments">(gnutls_ocsp_resp_const_t <var class="var">resp</var>, gnutls_ocsp_print_formats_t <var class="var">format</var>, gnutls_datum_t * <var class="var">out</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005fresp_005fprint"> &para;</a></span></dt>
<dd><p><var class="var">resp</var>: The data to be printed
</p>
<p><var class="var">format</var>: Indicate the format to use
</p>
<p><var class="var">out</var>: Newly allocated datum with (0) terminated string.
</p>
<p>This function will pretty print a OCSP response, suitable for
display to a human.
</p>
<p>If the format is <code class="code">GNUTLS_OCSP_PRINT_FULL</code>  then all fields of the
response will be output, on multiple lines.
</p>
<p>The output  <code class="code">out</code> -&gt;data needs to be deallocate using <code class="code">gnutls_free()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005focsp_005fresp_005fverify-1"><span>gnutls_ocsp_resp_verify<a class="copiable-link" href="#gnutls_005focsp_005fresp_005fverify-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005focsp_005fresp_005fverify"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005fresp_005fverify"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ocsp_resp_verify</strong> <code class="def-code-arguments">(gnutls_ocsp_resp_const_t <var class="var">resp</var>, gnutls_x509_trust_list_t <var class="var">trustlist</var>, unsigned int * <var class="var">verify</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005fresp_005fverify"> &para;</a></span></dt>
<dd><p><var class="var">resp</var>: should contain a <code class="code">gnutls_ocsp_resp_t</code>  type
</p>
<p><var class="var">trustlist</var>: trust anchors as a <code class="code">gnutls_x509_trust_list_t</code>  type
</p>
<p><var class="var">verify</var>: output variable with verification status, an <code class="code">gnutls_ocsp_verify_reason_t</code> 
</p>
<p><var class="var">flags</var>: verification flags from <code class="code">gnutls_certificate_verify_flags</code> 
</p>
<p>Verify signature of the Basic OCSP Response against the public key
in the certificate of a trusted signer.  The  <code class="code">trustlist</code> should be
populated with trust anchors.  The function will extract the signer
certificate from the Basic OCSP Response and will verify it against
the  <code class="code">trustlist</code> .  A trusted signer is a certificate that is either
in  <code class="code">trustlist</code> , or it is signed directly by a certificate in
 <code class="code">trustlist</code> and has the id-ad-ocspSigning Extended Key Usage bit
set.
</p>
<p>The output  <code class="code">verify</code> variable will hold verification status codes
(e.g., <code class="code">GNUTLS_OCSP_VERIFY_SIGNER_NOT_FOUND</code> ,
<code class="code">GNUTLS_OCSP_VERIFY_INSECURE_ALGORITHM</code> ) which are only valid if the
function returned <code class="code">GNUTLS_E_SUCCESS</code> .
</p>
<p>Note that the function returns <code class="code">GNUTLS_E_SUCCESS</code>  even when
verification failed.  The caller must always inspect the  <code class="code">verify</code> variable to find out the verification status.
</p>
<p>The  <code class="code">flags</code> variable should be 0 for now.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005focsp_005fresp_005fverify_005fdirect-1"><span>gnutls_ocsp_resp_verify_direct<a class="copiable-link" href="#gnutls_005focsp_005fresp_005fverify_005fdirect-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005focsp_005fresp_005fverify_005fdirect"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005focsp_005fresp_005fverify_005fdirect"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_ocsp_resp_verify_direct</strong> <code class="def-code-arguments">(gnutls_ocsp_resp_const_t <var class="var">resp</var>, gnutls_x509_crt_t <var class="var">issuer</var>, unsigned int * <var class="var">verify</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005focsp_005fresp_005fverify_005fdirect"> &para;</a></span></dt>
<dd><p><var class="var">resp</var>: should contain a <code class="code">gnutls_ocsp_resp_t</code>  type
</p>
<p><var class="var">issuer</var>: certificate believed to have signed the response
</p>
<p><var class="var">verify</var>: output variable with verification status, an <code class="code">gnutls_ocsp_verify_reason_t</code> 
</p>
<p><var class="var">flags</var>: verification flags from <code class="code">gnutls_certificate_verify_flags</code> 
</p>
<p>Verify signature of the Basic OCSP Response against the public key
in the  <code class="code">issuer</code> certificate.
</p>
<p>The output  <code class="code">verify</code> variable will hold verification status codes
(e.g., <code class="code">GNUTLS_OCSP_VERIFY_SIGNER_NOT_FOUND</code> ,
<code class="code">GNUTLS_OCSP_VERIFY_INSECURE_ALGORITHM</code> ) which are only valid if the
function returned <code class="code">GNUTLS_E_SUCCESS</code> .
</p>
<p>Note that the function returns <code class="code">GNUTLS_E_SUCCESS</code>  even when
verification failed.  The caller must always inspect the  <code class="code">verify</code> variable to find out the verification status.
</p>
<p>The  <code class="code">flags</code> variable should be 0 for now.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>


<hr>
</div>
<div class="section-level-extent" id="PKCS-12-API">
<div class="nav-panel">
<p>
Next: <a href="#PKCS-11-API" accesskey="n" rel="next">Hardware token via PKCS 11 API</a>, Previous: <a href="#OCSP-API" accesskey="p" rel="prev"><abbr class="acronym">OCSP</abbr> API</a>, Up: <a href="#API-reference" accesskey="u" rel="up">API reference</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="PKCS-12-API-1"><span>E.6 PKCS 12 API<a class="copiable-link" href="#PKCS-12-API-1"> &para;</a></span></h3>

<p>The following functions are to be used for PKCS 12 handling.
Their prototypes lie in <samp class="file">gnutls/pkcs12.h</samp>.
</p>

<h4 class="subheading" id="gnutls_005fpkcs12_005fbag_005fdecrypt-1"><span>gnutls_pkcs12_bag_decrypt<a class="copiable-link" href="#gnutls_005fpkcs12_005fbag_005fdecrypt-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs12_005fbag_005fdecrypt"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs12_005fbag_005fdecrypt"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs12_bag_decrypt</strong> <code class="def-code-arguments">(gnutls_pkcs12_bag_t <var class="var">bag</var>, const char * <var class="var">pass</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs12_005fbag_005fdecrypt"> &para;</a></span></dt>
<dd><p><var class="var">bag</var>: The bag
</p>
<p><var class="var">pass</var>: The password used for encryption, must be ASCII.
</p>
<p>This function will decrypt the given encrypted bag and return 0 on
success.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs12_005fbag_005fdeinit-1"><span>gnutls_pkcs12_bag_deinit<a class="copiable-link" href="#gnutls_005fpkcs12_005fbag_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs12_005fbag_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs12_005fbag_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_pkcs12_bag_deinit</strong> <code class="def-code-arguments">(gnutls_pkcs12_bag_t <var class="var">bag</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs12_005fbag_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">bag</var>: A pointer to the type to be initialized
</p>
<p>This function will deinitialize a PKCS12 Bag structure.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs12_005fbag_005fenc_005finfo-1"><span>gnutls_pkcs12_bag_enc_info<a class="copiable-link" href="#gnutls_005fpkcs12_005fbag_005fenc_005finfo-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs12_005fbag_005fenc_005finfo"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs12_005fbag_005fenc_005finfo"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs12_bag_enc_info</strong> <code class="def-code-arguments">(gnutls_pkcs12_bag_t <var class="var">bag</var>, unsigned int * <var class="var">schema</var>, unsigned int * <var class="var">cipher</var>, void * <var class="var">salt</var>, unsigned int * <var class="var">salt_size</var>, unsigned int * <var class="var">iter_count</var>, char ** <var class="var">oid</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs12_005fbag_005fenc_005finfo"> &para;</a></span></dt>
<dd><p><var class="var">bag</var>: The bag
</p>
<p><var class="var">schema</var>: indicate the schema as one of <code class="code">gnutls_pkcs_encrypt_flags_t</code> 
</p>
<p><var class="var">cipher</var>: the cipher used as <code class="code">gnutls_cipher_algorithm_t</code> 
</p>
<p><var class="var">salt</var>: PBKDF2 salt (if non-NULL then  <code class="code">salt_size</code> initially holds its size)
</p>
<p><var class="var">salt_size</var>: PBKDF2 salt size
</p>
<p><var class="var">iter_count</var>: PBKDF2 iteration count
</p>
<p><var class="var">oid</var>: if non-NULL it will contain an allocated null-terminated variable with the OID
</p>
<p>This function will provide information on the encryption algorithms used
in an encrypted bag. If the structure algorithms
are unknown the code <code class="code">GNUTLS_E_UNKNOWN_CIPHER_TYPE</code>  will be returned,
and only  <code class="code">oid</code> , will be set. That is,  <code class="code">oid</code> will be set on encrypted bags
whether supported or not. It must be deinitialized using <code class="code">gnutls_free()</code> .
The other variables are only set on supported structures.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_INVALID_REQUEST</code>  if the provided bag isn&rsquo;t encrypted,
<code class="code">GNUTLS_E_UNKNOWN_CIPHER_TYPE</code>  if the structure&rsquo;s encryption isn&rsquo;t supported, or
another negative error code in case of a failure. Zero on success.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs12_005fbag_005fencrypt-1"><span>gnutls_pkcs12_bag_encrypt<a class="copiable-link" href="#gnutls_005fpkcs12_005fbag_005fencrypt-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs12_005fbag_005fencrypt"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs12_005fbag_005fencrypt"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs12_bag_encrypt</strong> <code class="def-code-arguments">(gnutls_pkcs12_bag_t <var class="var">bag</var>, const char * <var class="var">pass</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs12_005fbag_005fencrypt"> &para;</a></span></dt>
<dd><p><var class="var">bag</var>: The bag
</p>
<p><var class="var">pass</var>: The password used for encryption, must be ASCII
</p>
<p><var class="var">flags</var>: should be one of <code class="code">gnutls_pkcs_encrypt_flags_t</code>  elements bitwise or&rsquo;d
</p>
<p>This function will encrypt the given bag.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
otherwise a negative error code is returned.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs12_005fbag_005fget_005fcount-1"><span>gnutls_pkcs12_bag_get_count<a class="copiable-link" href="#gnutls_005fpkcs12_005fbag_005fget_005fcount-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs12_005fbag_005fget_005fcount"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs12_005fbag_005fget_005fcount"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs12_bag_get_count</strong> <code class="def-code-arguments">(gnutls_pkcs12_bag_t <var class="var">bag</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs12_005fbag_005fget_005fcount"> &para;</a></span></dt>
<dd><p><var class="var">bag</var>: The bag
</p>
<p>This function will return the number of the elements within the bag.
</p>
<p><strong class="strong">Returns:</strong> Number of elements in bag, or an negative error code on
error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs12_005fbag_005fget_005fdata-1"><span>gnutls_pkcs12_bag_get_data<a class="copiable-link" href="#gnutls_005fpkcs12_005fbag_005fget_005fdata-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs12_005fbag_005fget_005fdata"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs12_005fbag_005fget_005fdata"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs12_bag_get_data</strong> <code class="def-code-arguments">(gnutls_pkcs12_bag_t <var class="var">bag</var>, unsigned <var class="var">indx</var>, gnutls_datum_t * <var class="var">data</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs12_005fbag_005fget_005fdata"> &para;</a></span></dt>
<dd><p><var class="var">bag</var>: The bag
</p>
<p><var class="var">indx</var>: The element of the bag to get the data from
</p>
<p><var class="var">data</var>: where the bag&rsquo;s data will be. Should be treated as constant.
</p>
<p>This function will return the bag&rsquo;s data. The data is a constant
that is stored into the bag.  Should not be accessed after the bag
is deleted.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs12_005fbag_005fget_005ffriendly_005fname-1"><span>gnutls_pkcs12_bag_get_friendly_name<a class="copiable-link" href="#gnutls_005fpkcs12_005fbag_005fget_005ffriendly_005fname-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs12_005fbag_005fget_005ffriendly_005fname"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs12_005fbag_005fget_005ffriendly_005fname"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs12_bag_get_friendly_name</strong> <code class="def-code-arguments">(gnutls_pkcs12_bag_t <var class="var">bag</var>, unsigned <var class="var">indx</var>, char ** <var class="var">name</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs12_005fbag_005fget_005ffriendly_005fname"> &para;</a></span></dt>
<dd><p><var class="var">bag</var>: The bag
</p>
<p><var class="var">indx</var>: The bag&rsquo;s element to add the id
</p>
<p><var class="var">name</var>: will hold a pointer to the name (to be treated as const)
</p>
<p>This function will return the friendly name, of the specified bag
element.  The key ID is usually used to distinguish the local
private key and the certificate pair.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value. or a negative error code on error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs12_005fbag_005fget_005fkey_005fid-1"><span>gnutls_pkcs12_bag_get_key_id<a class="copiable-link" href="#gnutls_005fpkcs12_005fbag_005fget_005fkey_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs12_005fbag_005fget_005fkey_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs12_005fbag_005fget_005fkey_005fid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs12_bag_get_key_id</strong> <code class="def-code-arguments">(gnutls_pkcs12_bag_t <var class="var">bag</var>, unsigned <var class="var">indx</var>, gnutls_datum_t * <var class="var">id</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs12_005fbag_005fget_005fkey_005fid"> &para;</a></span></dt>
<dd><p><var class="var">bag</var>: The bag
</p>
<p><var class="var">indx</var>: The bag&rsquo;s element to add the id
</p>
<p><var class="var">id</var>: where the ID will be copied (to be treated as const)
</p>
<p>This function will return the key ID, of the specified bag element.
The key ID is usually used to distinguish the local private key and
the certificate pair.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value. or a negative error code on error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs12_005fbag_005fget_005ftype-1"><span>gnutls_pkcs12_bag_get_type<a class="copiable-link" href="#gnutls_005fpkcs12_005fbag_005fget_005ftype-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs12_005fbag_005fget_005ftype"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs12_005fbag_005fget_005ftype"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs12_bag_get_type</strong> <code class="def-code-arguments">(gnutls_pkcs12_bag_t <var class="var">bag</var>, unsigned <var class="var">indx</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs12_005fbag_005fget_005ftype"> &para;</a></span></dt>
<dd><p><var class="var">bag</var>: The bag
</p>
<p><var class="var">indx</var>: The element of the bag to get the type
</p>
<p>This function will return the bag&rsquo;s type.
</p>
<p><strong class="strong">Returns:</strong> On error a negative error value or one of the <code class="code">gnutls_pkcs12_bag_type_t</code>  enumerations.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs12_005fbag_005finit-1"><span>gnutls_pkcs12_bag_init<a class="copiable-link" href="#gnutls_005fpkcs12_005fbag_005finit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs12_005fbag_005finit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs12_005fbag_005finit"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs12_bag_init</strong> <code class="def-code-arguments">(gnutls_pkcs12_bag_t * <var class="var">bag</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs12_005fbag_005finit"> &para;</a></span></dt>
<dd><p><var class="var">bag</var>: A pointer to the type to be initialized
</p>
<p>This function will initialize a PKCS12 bag structure. PKCS12 Bags
usually contain private keys, lists of X.509 Certificates and X.509
Certificate revocation lists.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs12_005fbag_005fset_005fcrl-1"><span>gnutls_pkcs12_bag_set_crl<a class="copiable-link" href="#gnutls_005fpkcs12_005fbag_005fset_005fcrl-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs12_005fbag_005fset_005fcrl"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs12_005fbag_005fset_005fcrl"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs12_bag_set_crl</strong> <code class="def-code-arguments">(gnutls_pkcs12_bag_t <var class="var">bag</var>, gnutls_x509_crl_t <var class="var">crl</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs12_005fbag_005fset_005fcrl"> &para;</a></span></dt>
<dd><p><var class="var">bag</var>: The bag
</p>
<p><var class="var">crl</var>: the CRL to be copied.
</p>
<p>This function will insert the given CRL into the
bag. This is just a wrapper over <code class="code">gnutls_pkcs12_bag_set_data()</code> .
</p>
<p><strong class="strong">Returns:</strong> the index of the added bag on success, or a negative error code
on failure.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs12_005fbag_005fset_005fcrt-1"><span>gnutls_pkcs12_bag_set_crt<a class="copiable-link" href="#gnutls_005fpkcs12_005fbag_005fset_005fcrt-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs12_005fbag_005fset_005fcrt"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs12_005fbag_005fset_005fcrt"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs12_bag_set_crt</strong> <code class="def-code-arguments">(gnutls_pkcs12_bag_t <var class="var">bag</var>, gnutls_x509_crt_t <var class="var">crt</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs12_005fbag_005fset_005fcrt"> &para;</a></span></dt>
<dd><p><var class="var">bag</var>: The bag
</p>
<p><var class="var">crt</var>: the certificate to be copied.
</p>
<p>This function will insert the given certificate into the
bag. This is just a wrapper over <code class="code">gnutls_pkcs12_bag_set_data()</code> .
</p>
<p><strong class="strong">Returns:</strong> the index of the added bag on success, or a negative
value on failure.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs12_005fbag_005fset_005fdata-1"><span>gnutls_pkcs12_bag_set_data<a class="copiable-link" href="#gnutls_005fpkcs12_005fbag_005fset_005fdata-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs12_005fbag_005fset_005fdata"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs12_005fbag_005fset_005fdata"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs12_bag_set_data</strong> <code class="def-code-arguments">(gnutls_pkcs12_bag_t <var class="var">bag</var>, gnutls_pkcs12_bag_type_t <var class="var">type</var>, const gnutls_datum_t * <var class="var">data</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs12_005fbag_005fset_005fdata"> &para;</a></span></dt>
<dd><p><var class="var">bag</var>: The bag
</p>
<p><var class="var">type</var>: The data&rsquo;s type
</p>
<p><var class="var">data</var>: the data to be copied.
</p>
<p>This function will insert the given data of the given type into
the bag.
</p>
<p><strong class="strong">Returns:</strong> the index of the added bag on success, or a negative
value on error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs12_005fbag_005fset_005ffriendly_005fname-1"><span>gnutls_pkcs12_bag_set_friendly_name<a class="copiable-link" href="#gnutls_005fpkcs12_005fbag_005fset_005ffriendly_005fname-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs12_005fbag_005fset_005ffriendly_005fname"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs12_005fbag_005fset_005ffriendly_005fname"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs12_bag_set_friendly_name</strong> <code class="def-code-arguments">(gnutls_pkcs12_bag_t <var class="var">bag</var>, unsigned <var class="var">indx</var>, const char * <var class="var">name</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs12_005fbag_005fset_005ffriendly_005fname"> &para;</a></span></dt>
<dd><p><var class="var">bag</var>: The bag
</p>
<p><var class="var">indx</var>: The bag&rsquo;s element to add the id
</p>
<p><var class="var">name</var>: the name
</p>
<p>This function will add the given key friendly name, to the
specified, by the index, bag element. The name will be encoded as
a &rsquo;Friendly name&rsquo; bag attribute, which is usually used to set a
user name to the local private key and the certificate pair.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value. or a negative error code on error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs12_005fbag_005fset_005fkey_005fid-1"><span>gnutls_pkcs12_bag_set_key_id<a class="copiable-link" href="#gnutls_005fpkcs12_005fbag_005fset_005fkey_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs12_005fbag_005fset_005fkey_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs12_005fbag_005fset_005fkey_005fid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs12_bag_set_key_id</strong> <code class="def-code-arguments">(gnutls_pkcs12_bag_t <var class="var">bag</var>, unsigned <var class="var">indx</var>, const gnutls_datum_t * <var class="var">id</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs12_005fbag_005fset_005fkey_005fid"> &para;</a></span></dt>
<dd><p><var class="var">bag</var>: The bag
</p>
<p><var class="var">indx</var>: The bag&rsquo;s element to add the id
</p>
<p><var class="var">id</var>: the ID
</p>
<p>This function will add the given key ID, to the specified, by the
index, bag element. The key ID will be encoded as a &rsquo;Local key
identifier&rsquo; bag attribute, which is usually used to distinguish
the local private key and the certificate pair.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value. or a negative error code on error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs12_005fbag_005fset_005fprivkey-1"><span>gnutls_pkcs12_bag_set_privkey<a class="copiable-link" href="#gnutls_005fpkcs12_005fbag_005fset_005fprivkey-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs12_005fbag_005fset_005fprivkey"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs12_005fbag_005fset_005fprivkey"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs12_bag_set_privkey</strong> <code class="def-code-arguments">(gnutls_pkcs12_bag_t <var class="var">bag</var>, gnutls_x509_privkey_t <var class="var">privkey</var>, const char * <var class="var">password</var>, unsigned <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs12_005fbag_005fset_005fprivkey"> &para;</a></span></dt>
<dd><p><var class="var">bag</var>: The bag
</p>
<p><var class="var">privkey</var>: the private key to be copied.
</p>
<p><var class="var">password</var>: the password to protect the key with (may be <code class="code">NULL</code> )
</p>
<p><var class="var">flags</var>: should be one of <code class="code">gnutls_pkcs_encrypt_flags_t</code>  elements bitwise or&rsquo;d
</p>
<p>This function will insert the given private key into the
bag. This is just a wrapper over <code class="code">gnutls_pkcs12_bag_set_data()</code> .
</p>
<p><strong class="strong">Returns:</strong> the index of the added bag on success, or a negative
value on failure.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs12_005fdeinit-1"><span>gnutls_pkcs12_deinit<a class="copiable-link" href="#gnutls_005fpkcs12_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs12_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs12_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_pkcs12_deinit</strong> <code class="def-code-arguments">(gnutls_pkcs12_t <var class="var">pkcs12</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs12_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">pkcs12</var>: The type to be initialized
</p>
<p>This function will deinitialize a PKCS12 type.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs12_005fexport-1"><span>gnutls_pkcs12_export<a class="copiable-link" href="#gnutls_005fpkcs12_005fexport-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs12_005fexport"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs12_005fexport"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs12_export</strong> <code class="def-code-arguments">(gnutls_pkcs12_t <var class="var">pkcs12</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, void * <var class="var">output_data</var>, size_t * <var class="var">output_data_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs12_005fexport"> &para;</a></span></dt>
<dd><p><var class="var">pkcs12</var>: A pkcs12 type
</p>
<p><var class="var">format</var>: the format of output params. One of PEM or DER.
</p>
<p><var class="var">output_data</var>: will contain a structure PEM or DER encoded
</p>
<p><var class="var">output_data_size</var>: holds the size of output_data (and will be
replaced by the actual size of parameters)
</p>
<p>This function will export the pkcs12 structure to DER or PEM format.
</p>
<p>If the buffer provided is not long enough to hold the output, then
*output_data_size will be updated and GNUTLS_E_SHORT_MEMORY_BUFFER
will be returned.
</p>
<p>If the structure is PEM encoded, it will have a header
of &quot;BEGIN PKCS12&quot;.
</p>
<p><strong class="strong">Returns:</strong> In case of failure a negative error code will be
returned, and 0 on success.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs12_005fexport2-1"><span>gnutls_pkcs12_export2<a class="copiable-link" href="#gnutls_005fpkcs12_005fexport2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs12_005fexport2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs12_005fexport2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs12_export2</strong> <code class="def-code-arguments">(gnutls_pkcs12_t <var class="var">pkcs12</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, gnutls_datum_t * <var class="var">out</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs12_005fexport2"> &para;</a></span></dt>
<dd><p><var class="var">pkcs12</var>: A pkcs12 type
</p>
<p><var class="var">format</var>: the format of output params. One of PEM or DER.
</p>
<p><var class="var">out</var>: will contain a structure PEM or DER encoded
</p>
<p>This function will export the pkcs12 structure to DER or PEM format.
</p>
<p>The output buffer is allocated using <code class="code">gnutls_malloc()</code> .
</p>
<p>If the structure is PEM encoded, it will have a header
of &quot;BEGIN PKCS12&quot;.
</p>
<p><strong class="strong">Returns:</strong> In case of failure a negative error code will be
returned, and 0 on success.
</p>
<p><strong class="strong">Since:</strong> 3.1.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs12_005fgenerate_005fmac-1"><span>gnutls_pkcs12_generate_mac<a class="copiable-link" href="#gnutls_005fpkcs12_005fgenerate_005fmac-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs12_005fgenerate_005fmac"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs12_005fgenerate_005fmac"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs12_generate_mac</strong> <code class="def-code-arguments">(gnutls_pkcs12_t <var class="var">pkcs12</var>, const char * <var class="var">pass</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs12_005fgenerate_005fmac"> &para;</a></span></dt>
<dd><p><var class="var">pkcs12</var>: A pkcs12 type
</p>
<p><var class="var">pass</var>: The password for the MAC
</p>
<p>This function will generate a MAC for the PKCS12 structure.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs12_005fgenerate_005fmac2-1"><span>gnutls_pkcs12_generate_mac2<a class="copiable-link" href="#gnutls_005fpkcs12_005fgenerate_005fmac2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs12_005fgenerate_005fmac2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs12_005fgenerate_005fmac2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs12_generate_mac2</strong> <code class="def-code-arguments">(gnutls_pkcs12_t <var class="var">pkcs12</var>, gnutls_mac_algorithm_t <var class="var">mac</var>, const char * <var class="var">pass</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs12_005fgenerate_005fmac2"> &para;</a></span></dt>
<dd><p><var class="var">pkcs12</var>: A pkcs12 type
</p>
<p><var class="var">mac</var>: the MAC algorithm to use
</p>
<p><var class="var">pass</var>: The password for the MAC
</p>
<p>This function will generate a MAC for the PKCS12 structure.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs12_005fgenerate_005fmac3-1"><span>gnutls_pkcs12_generate_mac3<a class="copiable-link" href="#gnutls_005fpkcs12_005fgenerate_005fmac3-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs12_005fgenerate_005fmac3"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs12_005fgenerate_005fmac3"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs12_generate_mac3</strong> <code class="def-code-arguments">(gnutls_pkcs12_t <var class="var">pkcs12</var>, gnutls_mac_algorithm_t <var class="var">mac</var>, const char * <var class="var">pass</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs12_005fgenerate_005fmac3"> &para;</a></span></dt>
<dd><p><var class="var">pkcs12</var>: A pkcs12 type
</p>
<p><var class="var">mac</var>: the MAC algorithm to use
</p>
<p><var class="var">pass</var>: The password for the MAC
</p>
<p><var class="var">flags</var>: an ORed sequence of gnutls_pkcs12_flags_t
</p>
<p>This function will generate a MAC for the PKCS12 structure.
</p>
<p>If  <code class="code">flags</code> contains <code class="code">GNUTLS_PKCS12_USE_PBMAC1</code> , it uses PBMAC1 key
derivation function instead of the PKCS<code class="code">12</code>  one.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs12_005fget_005fbag-1"><span>gnutls_pkcs12_get_bag<a class="copiable-link" href="#gnutls_005fpkcs12_005fget_005fbag-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs12_005fget_005fbag"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs12_005fget_005fbag"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs12_get_bag</strong> <code class="def-code-arguments">(gnutls_pkcs12_t <var class="var">pkcs12</var>, int <var class="var">indx</var>, gnutls_pkcs12_bag_t <var class="var">bag</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs12_005fget_005fbag"> &para;</a></span></dt>
<dd><p><var class="var">pkcs12</var>: A pkcs12 type
</p>
<p><var class="var">indx</var>: contains the index of the bag to extract
</p>
<p><var class="var">bag</var>: An initialized bag, where the contents of the bag will be copied
</p>
<p>This function will return a Bag from the PKCS12 structure.
</p>
<p>After the last Bag has been read
<code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  will be returned.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs12_005fimport-1"><span>gnutls_pkcs12_import<a class="copiable-link" href="#gnutls_005fpkcs12_005fimport-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs12_005fimport"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs12_005fimport"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs12_import</strong> <code class="def-code-arguments">(gnutls_pkcs12_t <var class="var">pkcs12</var>, const gnutls_datum_t * <var class="var">data</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs12_005fimport"> &para;</a></span></dt>
<dd><p><var class="var">pkcs12</var>: The data to store the parsed PKCS12.
</p>
<p><var class="var">data</var>: The DER or PEM encoded PKCS12.
</p>
<p><var class="var">format</var>: One of DER or PEM
</p>
<p><var class="var">flags</var>: an ORed sequence of gnutls_privkey_pkcs8_flags
</p>
<p>This function will convert the given DER or PEM encoded PKCS12
to the native gnutls_pkcs12_t format. The output will be stored in &rsquo;pkcs12&rsquo;.
</p>
<p>If the PKCS12 is PEM encoded it should have a header of &quot;PKCS12&quot;.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs12_005finit-1"><span>gnutls_pkcs12_init<a class="copiable-link" href="#gnutls_005fpkcs12_005finit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs12_005finit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs12_005finit"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs12_init</strong> <code class="def-code-arguments">(gnutls_pkcs12_t * <var class="var">pkcs12</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs12_005finit"> &para;</a></span></dt>
<dd><p><var class="var">pkcs12</var>: A pointer to the type to be initialized
</p>
<p>This function will initialize a PKCS12 type. PKCS12 structures
usually contain lists of X.509 Certificates and X.509 Certificate
revocation lists.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs12_005fmac_005finfo-1"><span>gnutls_pkcs12_mac_info<a class="copiable-link" href="#gnutls_005fpkcs12_005fmac_005finfo-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs12_005fmac_005finfo"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs12_005fmac_005finfo"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs12_mac_info</strong> <code class="def-code-arguments">(gnutls_pkcs12_t <var class="var">pkcs12</var>, unsigned int * <var class="var">mac</var>, void * <var class="var">salt</var>, unsigned int * <var class="var">salt_size</var>, unsigned int * <var class="var">iter_count</var>, char ** <var class="var">oid</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs12_005fmac_005finfo"> &para;</a></span></dt>
<dd><p><var class="var">pkcs12</var>: A pkcs12 type
</p>
<p><var class="var">mac</var>: the MAC algorithm used as <code class="code">gnutls_mac_algorithm_t</code> 
</p>
<p><var class="var">salt</var>: the salt used for string to key (if non-NULL then  <code class="code">salt_size</code> initially holds its size)
</p>
<p><var class="var">salt_size</var>: string to key salt size
</p>
<p><var class="var">iter_count</var>: string to key iteration count
</p>
<p><var class="var">oid</var>: if non-NULL it will contain an allocated null-terminated variable with the OID
</p>
<p>This function will provide information on the MAC algorithm used
in a PKCS <code class="code">12</code>  structure. If the structure algorithms
are unknown the code <code class="code">GNUTLS_E_UNKNOWN_HASH_ALGORITHM</code>  will be returned,
and only  <code class="code">oid</code> , will be set. That is,  <code class="code">oid</code> will be set on structures
with a MAC whether supported or not. It must be deinitialized using <code class="code">gnutls_free()</code> .
The other variables are only set on supported structures.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_INVALID_REQUEST</code>  if the provided structure doesn&rsquo;t contain a MAC,
<code class="code">GNUTLS_E_UNKNOWN_HASH_ALGORITHM</code>  if the structure&rsquo;s MAC isn&rsquo;t supported, or
another negative error code in case of a failure. Zero on success.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs12_005fset_005fbag-1"><span>gnutls_pkcs12_set_bag<a class="copiable-link" href="#gnutls_005fpkcs12_005fset_005fbag-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs12_005fset_005fbag"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs12_005fset_005fbag"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs12_set_bag</strong> <code class="def-code-arguments">(gnutls_pkcs12_t <var class="var">pkcs12</var>, gnutls_pkcs12_bag_t <var class="var">bag</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs12_005fset_005fbag"> &para;</a></span></dt>
<dd><p><var class="var">pkcs12</var>: should contain a gnutls_pkcs12_t type
</p>
<p><var class="var">bag</var>: An initialized bag
</p>
<p>This function will insert a Bag into the PKCS12 structure.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs12_005fsimple_005fparse-1"><span>gnutls_pkcs12_simple_parse<a class="copiable-link" href="#gnutls_005fpkcs12_005fsimple_005fparse-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs12_005fsimple_005fparse"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs12_005fsimple_005fparse-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs12_simple_parse</strong> <code class="def-code-arguments">(gnutls_pkcs12_t <var class="var">p12</var>, const char * <var class="var">password</var>, gnutls_x509_privkey_t * <var class="var">key</var>, gnutls_x509_crt_t ** <var class="var">chain</var>, unsigned int * <var class="var">chain_len</var>, gnutls_x509_crt_t ** <var class="var">extra_certs</var>, unsigned int * <var class="var">extra_certs_len</var>, gnutls_x509_crl_t * <var class="var">crl</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs12_005fsimple_005fparse-1"> &para;</a></span></dt>
<dd><p><var class="var">p12</var>: A pkcs12 type
</p>
<p><var class="var">password</var>: optional password used to decrypt the structure, bags and keys.
</p>
<p><var class="var">key</var>: a structure to store the parsed private key.
</p>
<p><var class="var">chain</var>: the corresponding to key certificate chain (may be <code class="code">NULL</code> )
</p>
<p><var class="var">chain_len</var>: will be updated with the number of additional (may be <code class="code">NULL</code> )
</p>
<p><var class="var">extra_certs</var>: optional pointer to receive an array of additional
certificates found in the PKCS12 structure (may be <code class="code">NULL</code> ).
</p>
<p><var class="var">extra_certs_len</var>: will be updated with the number of additional
certs (may be <code class="code">NULL</code> ).
</p>
<p><var class="var">crl</var>: an optional structure to store the parsed CRL (may be <code class="code">NULL</code> ).
</p>
<p><var class="var">flags</var>: should be zero or one of GNUTLS_PKCS12_SP_*
</p>
<p>This function parses a PKCS12 structure in  <code class="code">pkcs12</code> and extracts the
private key, the corresponding certificate chain, any additional
certificates and a CRL. The structures in  <code class="code">key</code> ,  <code class="code">chain</code>  <code class="code">crl</code> , and  <code class="code">extra_certs</code> must not be initialized.
</p>
<p>The  <code class="code">extra_certs</code> and  <code class="code">extra_certs_len</code> parameters are optional
and both may be set to <code class="code">NULL</code> . If either is non-<code class="code">NULL</code> , then both must
be set. The value for  <code class="code">extra_certs</code> is allocated
using <code class="code">gnutls_malloc()</code> .
</p>
<p>Encrypted PKCS12 bags and PKCS8 private keys are supported, but
only with password based security and the same password for all
operations.
</p>
<p>Note that a PKCS12 structure may contain many keys and/or certificates,
and there is no way to identify which key/certificate pair you want.
For this reason this function is useful for PKCS12 files that contain 
only one key/certificate pair and/or one CRL.
</p>
<p>If the provided structure has encrypted fields but no password
is provided then this function returns <code class="code">GNUTLS_E_DECRYPTION_FAILED</code> .
</p>
<p>Note that normally the chain constructed does not include self signed
certificates, to comply with TLS&rsquo; requirements. If, however, the flag 
<code class="code">GNUTLS_PKCS12_SP_INCLUDE_SELF_SIGNED</code>  is specified then
self signed certificates will be included in the chain.
</p>
<p>Prior to using this function the PKCS <code class="code">12</code>  structure integrity must
be verified using <code class="code">gnutls_pkcs12_verify_mac()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.1.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs12_005fverify_005fmac-1"><span>gnutls_pkcs12_verify_mac<a class="copiable-link" href="#gnutls_005fpkcs12_005fverify_005fmac-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs12_005fverify_005fmac"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs12_005fverify_005fmac"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs12_verify_mac</strong> <code class="def-code-arguments">(gnutls_pkcs12_t <var class="var">pkcs12</var>, const char * <var class="var">pass</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs12_005fverify_005fmac"> &para;</a></span></dt>
<dd><p><var class="var">pkcs12</var>: should contain a gnutls_pkcs12_t type
</p>
<p><var class="var">pass</var>: The password for the MAC
</p>
<p>This function will verify the MAC for the PKCS12 structure.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>


<hr>
</div>
<div class="section-level-extent" id="PKCS-11-API">
<div class="nav-panel">
<p>
Next: <a href="#TPM-API" accesskey="n" rel="next">TPM API</a>, Previous: <a href="#PKCS-12-API" accesskey="p" rel="prev">PKCS 12 API</a>, Up: <a href="#API-reference" accesskey="u" rel="up">API reference</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Hardware-token-via-PKCS-11-API"><span>E.7 Hardware token via PKCS 11 API<a class="copiable-link" href="#Hardware-token-via-PKCS-11-API"> &para;</a></span></h3>

<p>The following functions are to be used for PKCS 11 handling.
Their prototypes lie in <samp class="file">gnutls/pkcs11.h</samp>.
</p>

<h4 class="subheading" id="gnutls_005fpkcs11_005fadd_005fprovider-1"><span>gnutls_pkcs11_add_provider<a class="copiable-link" href="#gnutls_005fpkcs11_005fadd_005fprovider-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fadd_005fprovider"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fadd_005fprovider-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_add_provider</strong> <code class="def-code-arguments">(const char * <var class="var">name</var>, const char * <var class="var">params</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fadd_005fprovider-1"> &para;</a></span></dt>
<dd><p><var class="var">name</var>: The filename of the module
</p>
<p><var class="var">params</var>: should be NULL or a known string (see description)
</p>
<p>This function will load and add a PKCS 11 module to the module
list used in gnutls. After this function is called the module will
be used for PKCS 11 operations.
</p>
<p>When loading a module to be used for certificate verification,
use the string &rsquo;trusted&rsquo; as  <code class="code">params</code> .
</p>
<p>Note that this function is not thread safe.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fcopy_005fattached_005fextension-1"><span>gnutls_pkcs11_copy_attached_extension<a class="copiable-link" href="#gnutls_005fpkcs11_005fcopy_005fattached_005fextension-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fcopy_005fattached_005fextension"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fcopy_005fattached_005fextension"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_copy_attached_extension</strong> <code class="def-code-arguments">(const char * <var class="var">token_url</var>, gnutls_x509_crt_t <var class="var">crt</var>, gnutls_datum_t * <var class="var">data</var>, const char * <var class="var">label</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fcopy_005fattached_005fextension"> &para;</a></span></dt>
<dd><p><var class="var">token_url</var>: A PKCS <code class="code">11</code>  URL specifying a token
</p>
<p><var class="var">crt</var>: An X.509 certificate object
</p>
<p><var class="var">data</var>: the attached extension
</p>
<p><var class="var">label</var>: A name to be used for the attached extension (may be <code class="code">NULL</code> )
</p>
<p><var class="var">flags</var>: One of GNUTLS_PKCS11_OBJ_FLAG_*
</p>
<p>This function will copy an the attached extension in  <code class="code">data</code> for
the certificate provided in  <code class="code">crt</code> in the PKCS <code class="code">11</code>  token specified
by the URL (typically a trust module). The extension must be in
RFC5280 Extension format.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.8
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fcopy_005fpubkey-1"><span>gnutls_pkcs11_copy_pubkey<a class="copiable-link" href="#gnutls_005fpkcs11_005fcopy_005fpubkey-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fcopy_005fpubkey"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fcopy_005fpubkey"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_copy_pubkey</strong> <code class="def-code-arguments">(const char * <var class="var">token_url</var>, gnutls_pubkey_t <var class="var">pubkey</var>, const char * <var class="var">label</var>, const gnutls_datum_t * <var class="var">cid</var>, unsigned int <var class="var">key_usage</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fcopy_005fpubkey"> &para;</a></span></dt>
<dd><p><var class="var">token_url</var>: A PKCS <code class="code">11</code>  URL specifying a token
</p>
<p><var class="var">pubkey</var>: The public key to copy
</p>
<p><var class="var">label</var>: The name to be used for the stored data
</p>
<p><var class="var">cid</var>: The CKA_ID to set for the object -if NULL, the ID will be derived from the public key
</p>
<p><var class="var">key_usage</var>: One of GNUTLS_KEY_*
</p>
<p><var class="var">flags</var>: One of GNUTLS_PKCS11_OBJ_FLAG_*
</p>
<p>This function will copy a public key object into a PKCS <code class="code">11</code>  token specified by
a URL. Valid flags to mark the key: <code class="code">GNUTLS_PKCS11_OBJ_FLAG_MARK_TRUSTED</code> ,
<code class="code">GNUTLS_PKCS11_OBJ_FLAG_MARK_PRIVATE</code> , <code class="code">GNUTLS_PKCS11_OBJ_FLAG_MARK_CA</code> ,
<code class="code">GNUTLS_PKCS11_OBJ_FLAG_MARK_ALWAYS_AUTH</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.4.6
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fcopy_005fsecret_005fkey-1"><span>gnutls_pkcs11_copy_secret_key<a class="copiable-link" href="#gnutls_005fpkcs11_005fcopy_005fsecret_005fkey-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fcopy_005fsecret_005fkey"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fcopy_005fsecret_005fkey"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_copy_secret_key</strong> <code class="def-code-arguments">(const char * <var class="var">token_url</var>, gnutls_datum_t * <var class="var">key</var>, const char * <var class="var">label</var>, unsigned int <var class="var">key_usage</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fcopy_005fsecret_005fkey"> &para;</a></span></dt>
<dd><p><var class="var">token_url</var>: A PKCS <code class="code">11</code>  URL specifying a token
</p>
<p><var class="var">key</var>: The raw key
</p>
<p><var class="var">label</var>: A name to be used for the stored data
</p>
<p><var class="var">key_usage</var>: One of GNUTLS_KEY_*
</p>
<p><var class="var">flags</var>: One of GNUTLS_PKCS11_OBJ_FLAG_*
</p>
<p>This function will copy a raw secret (symmetric) key into a PKCS <code class="code">11</code>  
token specified by a URL. The key can be marked as sensitive or not.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fcopy_005fx509_005fcrt-1"><span>gnutls_pkcs11_copy_x509_crt<a class="copiable-link" href="#gnutls_005fpkcs11_005fcopy_005fx509_005fcrt-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fcopy_005fx509_005fcrt"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fcopy_005fx509_005fcrt"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_copy_x509_crt</strong> <code class="def-code-arguments">(const char * <var class="var">token_url</var>, gnutls_x509_crt_t <var class="var">crt</var>, const char * <var class="var">label</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fcopy_005fx509_005fcrt"> &para;</a></span></dt>
<dd><p><var class="var">token_url</var>: A PKCS <code class="code">11</code>  URL specifying a token
</p>
<p><var class="var">crt</var>: A certificate
</p>
<p><var class="var">label</var>: A name to be used for the stored data
</p>
<p><var class="var">flags</var>: One of GNUTLS_PKCS11_OBJ_FLAG_*
</p>
<p>This function will copy a certificate into a PKCS <code class="code">11</code>  token specified by
a URL. The certificate can be marked as trusted or not.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fcopy_005fx509_005fcrt2-1"><span>gnutls_pkcs11_copy_x509_crt2<a class="copiable-link" href="#gnutls_005fpkcs11_005fcopy_005fx509_005fcrt2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fcopy_005fx509_005fcrt2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fcopy_005fx509_005fcrt2-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_copy_x509_crt2</strong> <code class="def-code-arguments">(const char * <var class="var">token_url</var>, gnutls_x509_crt_t <var class="var">crt</var>, const char * <var class="var">label</var>, const gnutls_datum_t * <var class="var">cid</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fcopy_005fx509_005fcrt2-1"> &para;</a></span></dt>
<dd><p><var class="var">token_url</var>: A PKCS <code class="code">11</code>  URL specifying a token
</p>
<p><var class="var">crt</var>: The certificate to copy
</p>
<p><var class="var">label</var>: The name to be used for the stored data
</p>
<p><var class="var">cid</var>: The CKA_ID to set for the object -if NULL, the ID will be derived from the public key
</p>
<p><var class="var">flags</var>: One of GNUTLS_PKCS11_OBJ_FLAG_*
</p>
<p>This function will copy a certificate into a PKCS <code class="code">11</code>  token specified by
a URL. Valid flags to mark the certificate: <code class="code">GNUTLS_PKCS11_OBJ_FLAG_MARK_TRUSTED</code> ,
<code class="code">GNUTLS_PKCS11_OBJ_FLAG_MARK_PRIVATE</code> , <code class="code">GNUTLS_PKCS11_OBJ_FLAG_MARK_CA</code> ,
<code class="code">GNUTLS_PKCS11_OBJ_FLAG_MARK_ALWAYS_AUTH</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fcopy_005fx509_005fprivkey-1"><span>gnutls_pkcs11_copy_x509_privkey<a class="copiable-link" href="#gnutls_005fpkcs11_005fcopy_005fx509_005fprivkey-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fcopy_005fx509_005fprivkey"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fcopy_005fx509_005fprivkey"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_copy_x509_privkey</strong> <code class="def-code-arguments">(const char * <var class="var">token_url</var>, gnutls_x509_privkey_t <var class="var">key</var>, const char * <var class="var">label</var>, unsigned int <var class="var">key_usage</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fcopy_005fx509_005fprivkey"> &para;</a></span></dt>
<dd><p><var class="var">token_url</var>: A PKCS <code class="code">11</code>  URL specifying a token
</p>
<p><var class="var">key</var>: A private key
</p>
<p><var class="var">label</var>: A name to be used for the stored data
</p>
<p><var class="var">key_usage</var>: One of GNUTLS_KEY_*
</p>
<p><var class="var">flags</var>: One of GNUTLS_PKCS11_OBJ_* flags
</p>
<p>This function will copy a private key into a PKCS <code class="code">11</code>  token specified by
a URL.
</p>
<p>Since 3.6.3 the objects are marked as sensitive by default unless
<code class="code">GNUTLS_PKCS11_OBJ_FLAG_MARK_NOT_SENSITIVE</code>  is specified.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fcopy_005fx509_005fprivkey2-1"><span>gnutls_pkcs11_copy_x509_privkey2<a class="copiable-link" href="#gnutls_005fpkcs11_005fcopy_005fx509_005fprivkey2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fcopy_005fx509_005fprivkey2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fcopy_005fx509_005fprivkey2-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_copy_x509_privkey2</strong> <code class="def-code-arguments">(const char * <var class="var">token_url</var>, gnutls_x509_privkey_t <var class="var">key</var>, const char * <var class="var">label</var>, const gnutls_datum_t * <var class="var">cid</var>, unsigned int <var class="var">key_usage</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fcopy_005fx509_005fprivkey2-1"> &para;</a></span></dt>
<dd><p><var class="var">token_url</var>: A PKCS <code class="code">11</code>  URL specifying a token
</p>
<p><var class="var">key</var>: A private key
</p>
<p><var class="var">label</var>: A name to be used for the stored data
</p>
<p><var class="var">cid</var>: The CKA_ID to set for the object -if NULL, the ID will be derived from the public key
</p>
<p><var class="var">key_usage</var>: One of GNUTLS_KEY_*
</p>
<p><var class="var">flags</var>: One of GNUTLS_PKCS11_OBJ_* flags
</p>
<p>This function will copy a private key into a PKCS <code class="code">11</code>  token specified by
a URL.
</p>
<p>Since 3.6.3 the objects are marked as sensitive by default unless
<code class="code">GNUTLS_PKCS11_OBJ_FLAG_MARK_NOT_SENSITIVE</code>  is specified.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fcrt_005fis_005fknown-1"><span>gnutls_pkcs11_crt_is_known<a class="copiable-link" href="#gnutls_005fpkcs11_005fcrt_005fis_005fknown-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fcrt_005fis_005fknown"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fcrt_005fis_005fknown"><span class="category-def">Function: </span><span><code class="def-type">unsigned</code> <strong class="def-name">gnutls_pkcs11_crt_is_known</strong> <code class="def-code-arguments">(const char * <var class="var">url</var>, gnutls_x509_crt_t <var class="var">cert</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fcrt_005fis_005fknown"> &para;</a></span></dt>
<dd><p><var class="var">url</var>: A PKCS 11 url identifying a token
</p>
<p><var class="var">cert</var>: is the certificate to find issuer for
</p>
<p><var class="var">flags</var>: Use zero or flags from <code class="code">GNUTLS_PKCS11_OBJ_FLAG</code> .
</p>
<p>This function will check whether the provided certificate is stored
in the specified token. This is useful in combination with 
<code class="code">GNUTLS_PKCS11_OBJ_FLAG_RETRIEVE_TRUSTED</code>  or
<code class="code">GNUTLS_PKCS11_OBJ_FLAG_RETRIEVE_DISTRUSTED</code> ,
to check whether a CA is present or a certificate is distrusted in
a trust PKCS <code class="code">11</code>  module.
</p>
<p>This function can be used with a  <code class="code">url</code> of &quot;pkcs11:&quot;, and in that case all modules
will be searched. To restrict the modules to the marked as trusted in p11-kit
use the <code class="code">GNUTLS_PKCS11_OBJ_FLAG_PRESENT_IN_TRUSTED_MODULE</code>  flag.
</p>
<p>Note that the flag <code class="code">GNUTLS_PKCS11_OBJ_FLAG_RETRIEVE_DISTRUSTED</code>  is
specific to p11-kit trust modules.
</p>
<p><strong class="strong">Returns:</strong> If the certificate exists non-zero is returned, otherwise zero.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fdeinit-1"><span>gnutls_pkcs11_deinit<a class="copiable-link" href="#gnutls_005fpkcs11_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_pkcs11_deinit</strong> <code class="def-code-arguments">( <var class="var">void</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fdeinit"> &para;</a></span></dt>
<dd>
<p>This function will deinitialize the PKCS 11 subsystem in gnutls.
This function is only needed if you need to deinitialize the
subsystem without calling <code class="code">gnutls_global_deinit()</code> .
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fdelete_005furl-1"><span>gnutls_pkcs11_delete_url<a class="copiable-link" href="#gnutls_005fpkcs11_005fdelete_005furl-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fdelete_005furl"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fdelete_005furl-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_delete_url</strong> <code class="def-code-arguments">(const char * <var class="var">object_url</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fdelete_005furl-1"> &para;</a></span></dt>
<dd><p><var class="var">object_url</var>: The URL of the object to delete.
</p>
<p><var class="var">flags</var>: One of GNUTLS_PKCS11_OBJ_* flags
</p>
<p>This function will delete objects matching the given URL.
Note that not all tokens support the delete operation.
</p>
<p><strong class="strong">Returns:</strong> On success, the number of objects deleted is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fget_005fpin_005ffunction-1"><span>gnutls_pkcs11_get_pin_function<a class="copiable-link" href="#gnutls_005fpkcs11_005fget_005fpin_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fget_005fpin_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fget_005fpin_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">gnutls_pin_callback_t</code> <strong class="def-name">gnutls_pkcs11_get_pin_function</strong> <code class="def-code-arguments">(void ** <var class="var">userdata</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fget_005fpin_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">userdata</var>: data to be supplied to callback
</p>
<p>This function will return the callback function set using
<code class="code">gnutls_pkcs11_set_pin_function()</code> .
</p>
<p><strong class="strong">Returns:</strong> The function set or NULL otherwise.
</p>
<p><strong class="strong">Since:</strong> 3.1.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fget_005fraw_005fissuer-1"><span>gnutls_pkcs11_get_raw_issuer<a class="copiable-link" href="#gnutls_005fpkcs11_005fget_005fraw_005fissuer-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fget_005fraw_005fissuer"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fget_005fraw_005fissuer"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_get_raw_issuer</strong> <code class="def-code-arguments">(const char * <var class="var">url</var>, gnutls_x509_crt_t <var class="var">cert</var>, gnutls_datum_t * <var class="var">issuer</var>, gnutls_x509_crt_fmt_t <var class="var">fmt</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fget_005fraw_005fissuer"> &para;</a></span></dt>
<dd><p><var class="var">url</var>: A PKCS 11 url identifying a token
</p>
<p><var class="var">cert</var>: is the certificate to find issuer for
</p>
<p><var class="var">issuer</var>: Will hold the issuer if any in an allocated buffer.
</p>
<p><var class="var">fmt</var>: The format of the exported issuer.
</p>
<p><var class="var">flags</var>: Use zero or flags from <code class="code">GNUTLS_PKCS11_OBJ_FLAG</code> .
</p>
<p>This function will return the issuer of a given certificate, if it
is stored in the token. By default only marked as trusted issuers
are returned. If any issuer should be returned specify
<code class="code">GNUTLS_PKCS11_OBJ_FLAG_RETRIEVE_ANY</code>  in  <code class="code">flags</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.2.7
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fget_005fraw_005fissuer_005fby_005fdn-1"><span>gnutls_pkcs11_get_raw_issuer_by_dn<a class="copiable-link" href="#gnutls_005fpkcs11_005fget_005fraw_005fissuer_005fby_005fdn-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fget_005fraw_005fissuer_005fby_005fdn"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fget_005fraw_005fissuer_005fby_005fdn"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_get_raw_issuer_by_dn</strong> <code class="def-code-arguments">(const char * <var class="var">url</var>, const gnutls_datum_t * <var class="var">dn</var>, gnutls_datum_t * <var class="var">issuer</var>, gnutls_x509_crt_fmt_t <var class="var">fmt</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fget_005fraw_005fissuer_005fby_005fdn"> &para;</a></span></dt>
<dd><p><var class="var">url</var>: A PKCS 11 url identifying a token
</p>
<p><var class="var">dn</var>: is the DN to search for
</p>
<p><var class="var">issuer</var>: Will hold the issuer if any in an allocated buffer.
</p>
<p><var class="var">fmt</var>: The format of the exported issuer.
</p>
<p><var class="var">flags</var>: Use zero or flags from <code class="code">GNUTLS_PKCS11_OBJ_FLAG</code> .
</p>
<p>This function will return the certificate with the given DN, if it
is stored in the token. By default only marked as trusted issuers
are returned. If any issuer should be returned specify
<code class="code">GNUTLS_PKCS11_OBJ_FLAG_RETRIEVE_ANY</code>  in  <code class="code">flags</code> .
</p>
<p>The name of the function includes issuer because it can
be used to discover issuers of certificates.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fget_005fraw_005fissuer_005fby_005fsubject_005fkey_005fid-1"><span>gnutls_pkcs11_get_raw_issuer_by_subject_key_id<a class="copiable-link" href="#gnutls_005fpkcs11_005fget_005fraw_005fissuer_005fby_005fsubject_005fkey_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fget_005fraw_005fissuer_005fby_005fsubject_005fkey_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fget_005fraw_005fissuer_005fby_005fsubject_005fkey_005fid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_get_raw_issuer_by_subject_key_id</strong> <code class="def-code-arguments">(const char * <var class="var">url</var>, const gnutls_datum_t * <var class="var">dn</var>, const gnutls_datum_t * <var class="var">spki</var>, gnutls_datum_t * <var class="var">issuer</var>, gnutls_x509_crt_fmt_t <var class="var">fmt</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fget_005fraw_005fissuer_005fby_005fsubject_005fkey_005fid"> &para;</a></span></dt>
<dd><p><var class="var">url</var>: A PKCS 11 url identifying a token
</p>
<p><var class="var">dn</var>: is the DN to search for (may be <code class="code">NULL</code> )
</p>
<p><var class="var">spki</var>: is the subject key ID to search for
</p>
<p><var class="var">issuer</var>: Will hold the issuer if any in an allocated buffer.
</p>
<p><var class="var">fmt</var>: The format of the exported issuer.
</p>
<p><var class="var">flags</var>: Use zero or flags from <code class="code">GNUTLS_PKCS11_OBJ_FLAG</code> .
</p>
<p>This function will return the certificate with the given DN and  <code class="code">spki</code> , if it
is stored in the token. By default only marked as trusted issuers
are returned. If any issuer should be returned specify
<code class="code">GNUTLS_PKCS11_OBJ_FLAG_RETRIEVE_ANY</code>  in  <code class="code">flags</code> .
</p>
<p>The name of the function includes issuer because it can
be used to discover issuers of certificates.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.4.2
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005finit-1"><span>gnutls_pkcs11_init<a class="copiable-link" href="#gnutls_005fpkcs11_005finit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005finit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005finit-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_init</strong> <code class="def-code-arguments">(unsigned int <var class="var">flags</var>, const char * <var class="var">deprecated_config_file</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005finit-1"> &para;</a></span></dt>
<dd><p><var class="var">flags</var>: An ORed sequence of <code class="code">GNUTLS_PKCS11_FLAG_</code> *
</p>
<p><var class="var">deprecated_config_file</var>: either NULL or the location of a deprecated
configuration file
</p>
<p>This function will initialize the PKCS 11 subsystem in gnutls. It will
read configuration files if <code class="code">GNUTLS_PKCS11_FLAG_AUTO</code>  is used or allow
you to independently load PKCS 11 modules using <code class="code">gnutls_pkcs11_add_provider()</code> 
if <code class="code">GNUTLS_PKCS11_FLAG_MANUAL</code>  is specified.
</p>
<p>You don&rsquo;t need to call this function since GnuTLS 3.3.0 because it is being called
during the first request PKCS 11 operation. That call will assume the <code class="code">GNUTLS_PKCS11_FLAG_AUTO</code> 
flag. If another flags are required then it must be called independently
prior to any PKCS 11 operation.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fobj_005fdeinit-1"><span>gnutls_pkcs11_obj_deinit<a class="copiable-link" href="#gnutls_005fpkcs11_005fobj_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fobj_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fobj_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_pkcs11_obj_deinit</strong> <code class="def-code-arguments">(gnutls_pkcs11_obj_t <var class="var">obj</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fobj_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">obj</var>: The type to be deinitialized
</p>
<p>This function will deinitialize a certificate structure.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fobj_005fexport-1"><span>gnutls_pkcs11_obj_export<a class="copiable-link" href="#gnutls_005fpkcs11_005fobj_005fexport-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fobj_005fexport"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fobj_005fexport"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_obj_export</strong> <code class="def-code-arguments">(gnutls_pkcs11_obj_t <var class="var">obj</var>, void * <var class="var">output_data</var>, size_t * <var class="var">output_data_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fobj_005fexport"> &para;</a></span></dt>
<dd><p><var class="var">obj</var>: Holds the object
</p>
<p><var class="var">output_data</var>: will contain the object data
</p>
<p><var class="var">output_data_size</var>: holds the size of output_data (and will be
replaced by the actual size of parameters)
</p>
<p>This function will export the PKCS11 object data.  It is normal for
data to be inaccessible and in that case <code class="code">GNUTLS_E_INVALID_REQUEST</code> 
will be returned.
</p>
<p>If the buffer provided is not long enough to hold the output, then
*output_data_size is updated and GNUTLS_E_SHORT_MEMORY_BUFFER will
be returned.
</p>
<p><strong class="strong">Returns:</strong> In case of failure a negative error code will be
returned, and <code class="code">GNUTLS_E_SUCCESS</code>  (0) on success.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fobj_005fexport2-1"><span>gnutls_pkcs11_obj_export2<a class="copiable-link" href="#gnutls_005fpkcs11_005fobj_005fexport2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fobj_005fexport2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fobj_005fexport2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_obj_export2</strong> <code class="def-code-arguments">(gnutls_pkcs11_obj_t <var class="var">obj</var>, gnutls_datum_t * <var class="var">out</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fobj_005fexport2"> &para;</a></span></dt>
<dd><p><var class="var">obj</var>: Holds the object
</p>
<p><var class="var">out</var>: will contain the object data
</p>
<p>This function will export the PKCS11 object data.  It is normal for
data to be inaccessible and in that case <code class="code">GNUTLS_E_INVALID_REQUEST</code> 
will be returned.
</p>
<p>The output buffer is allocated using <code class="code">gnutls_malloc()</code> .
</p>
<p><strong class="strong">Returns:</strong> In case of failure a negative error code will be
returned, and <code class="code">GNUTLS_E_SUCCESS</code>  (0) on success.
</p>
<p><strong class="strong">Since:</strong> 3.1.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fobj_005fexport3-1"><span>gnutls_pkcs11_obj_export3<a class="copiable-link" href="#gnutls_005fpkcs11_005fobj_005fexport3-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fobj_005fexport3"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fobj_005fexport3"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_obj_export3</strong> <code class="def-code-arguments">(gnutls_pkcs11_obj_t <var class="var">obj</var>, gnutls_x509_crt_fmt_t <var class="var">fmt</var>, gnutls_datum_t * <var class="var">out</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fobj_005fexport3"> &para;</a></span></dt>
<dd><p><var class="var">obj</var>: Holds the object
</p>
<p><var class="var">fmt</var>: The format of the exported data
</p>
<p><var class="var">out</var>: will contain the object data
</p>
<p>This function will export the PKCS11 object data.  It is normal for
data to be inaccessible and in that case <code class="code">GNUTLS_E_INVALID_REQUEST</code> 
will be returned.
</p>
<p>The output buffer is allocated using <code class="code">gnutls_malloc()</code> .
</p>
<p><strong class="strong">Returns:</strong> In case of failure a negative error code will be
returned, and <code class="code">GNUTLS_E_SUCCESS</code>  (0) on success.
</p>
<p><strong class="strong">Since:</strong> 3.2.7
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fobj_005fexport_005furl-1"><span>gnutls_pkcs11_obj_export_url<a class="copiable-link" href="#gnutls_005fpkcs11_005fobj_005fexport_005furl-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fobj_005fexport_005furl"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fobj_005fexport_005furl"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_obj_export_url</strong> <code class="def-code-arguments">(gnutls_pkcs11_obj_t <var class="var">obj</var>, gnutls_pkcs11_url_type_t <var class="var">detailed</var>, char ** <var class="var">url</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fobj_005fexport_005furl"> &para;</a></span></dt>
<dd><p><var class="var">obj</var>: Holds the PKCS 11 certificate
</p>
<p><var class="var">detailed</var>: non zero if a detailed URL is required
</p>
<p><var class="var">url</var>: will contain an allocated url
</p>
<p>This function will export a URL identifying the given object.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fobj_005fflags_005fget_005fstr-1"><span>gnutls_pkcs11_obj_flags_get_str<a class="copiable-link" href="#gnutls_005fpkcs11_005fobj_005fflags_005fget_005fstr-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fobj_005fflags_005fget_005fstr"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fobj_005fflags_005fget_005fstr"><span class="category-def">Function: </span><span><code class="def-type">char *</code> <strong class="def-name">gnutls_pkcs11_obj_flags_get_str</strong> <code class="def-code-arguments">(unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fobj_005fflags_005fget_005fstr"> &para;</a></span></dt>
<dd><p><var class="var">flags</var>: holds the flags
</p>
<p>This function given an or-sequence of <code class="code">GNUTLS_PKCS11_OBJ_FLAG_MARK</code> ,
will return an allocated string with its description. The string
needs to be deallocated using <code class="code">gnutls_free()</code> .
</p>
<p><strong class="strong">Returns:</strong> If flags is zero <code class="code">NULL</code>  is returned, otherwise an allocated string.
</p>
<p><strong class="strong">Since:</strong> 3.3.7
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fobj_005fget_005fexts-1"><span>gnutls_pkcs11_obj_get_exts<a class="copiable-link" href="#gnutls_005fpkcs11_005fobj_005fget_005fexts-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fobj_005fget_005fexts"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fobj_005fget_005fexts"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_obj_get_exts</strong> <code class="def-code-arguments">(gnutls_pkcs11_obj_t <var class="var">obj</var>, gnutls_x509_ext_st ** <var class="var">exts</var>, unsigned int * <var class="var">exts_size</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fobj_005fget_005fexts"> &para;</a></span></dt>
<dd><p><var class="var">obj</var>: should contain a <code class="code">gnutls_pkcs11_obj_t</code>  type
</p>
<p><var class="var">exts</var>: a pointer to a <code class="code">gnutls_x509_ext_st</code>  pointer
</p>
<p><var class="var">exts_size</var>: will be updated with the number of  <code class="code">exts</code> 
</p>
<p><var class="var">flags</var>: Or sequence of <code class="code">GNUTLS_PKCS11_OBJ_</code> * flags 
</p>
<p>This function will return information about attached extensions
that associate to the provided object (which should be a certificate).
The extensions are the attached p11-kit trust module extensions.
</p>
<p>Each element of  <code class="code">exts</code> must be deinitialized using <code class="code">gnutls_x509_ext_deinit()</code> 
while  <code class="code">exts</code> should be deallocated using <code class="code">gnutls_free()</code> .
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  (0) on success or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 3.3.8
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fobj_005fget_005fflags-1"><span>gnutls_pkcs11_obj_get_flags<a class="copiable-link" href="#gnutls_005fpkcs11_005fobj_005fget_005fflags-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fobj_005fget_005fflags"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fobj_005fget_005fflags"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_obj_get_flags</strong> <code class="def-code-arguments">(gnutls_pkcs11_obj_t <var class="var">obj</var>, unsigned int * <var class="var">oflags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fobj_005fget_005fflags"> &para;</a></span></dt>
<dd><p><var class="var">obj</var>: The pkcs11 object
</p>
<p><var class="var">oflags</var>: Will hold the output flags
</p>
<p>This function will return the flags of the object.
The  <code class="code">oflags</code> will be flags from <code class="code">gnutls_pkcs11_obj_flags</code> . That is,
the <code class="code">GNUTLS_PKCS11_OBJ_FLAG_MARK_</code> * flags.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.7
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fobj_005fget_005finfo-1"><span>gnutls_pkcs11_obj_get_info<a class="copiable-link" href="#gnutls_005fpkcs11_005fobj_005fget_005finfo-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fobj_005fget_005finfo"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fobj_005fget_005finfo-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_obj_get_info</strong> <code class="def-code-arguments">(gnutls_pkcs11_obj_t <var class="var">obj</var>, gnutls_pkcs11_obj_info_t <var class="var">itype</var>, void * <var class="var">output</var>, size_t * <var class="var">output_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fobj_005fget_005finfo-1"> &para;</a></span></dt>
<dd><p><var class="var">obj</var>: should contain a <code class="code">gnutls_pkcs11_obj_t</code>  type
</p>
<p><var class="var">itype</var>: Denotes the type of information requested
</p>
<p><var class="var">output</var>: where output will be stored
</p>
<p><var class="var">output_size</var>: contains the maximum size of the output buffer and will be
overwritten with the actual size.
</p>
<p>This function will return information about the PKCS11 certificate
such as the label, id as well as token information where the key is
stored.
</p>
<p>When output is text, a null terminated string is written to  <code class="code">output</code> and its
string length is written to  <code class="code">output_size</code> (without null terminator). If the
buffer is too small,  <code class="code">output_size</code> will contain the expected buffer size
(with null terminator for text) and return <code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code> .
</p>
<p>In versions previously to 3.6.0 this function included the null terminator
to  <code class="code">output_size</code> . After 3.6.0 the output size doesn&rsquo;t include the terminator character.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  (0) on success or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fobj_005fget_005fptr-1"><span>gnutls_pkcs11_obj_get_ptr<a class="copiable-link" href="#gnutls_005fpkcs11_005fobj_005fget_005fptr-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fobj_005fget_005fptr"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fobj_005fget_005fptr-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_obj_get_ptr</strong> <code class="def-code-arguments">(gnutls_pkcs11_obj_t <var class="var">obj</var>, void ** <var class="var">ptr</var>, void ** <var class="var">session</var>, void ** <var class="var">ohandle</var>, unsigned long * <var class="var">slot_id</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fobj_005fget_005fptr-1"> &para;</a></span></dt>
<dd><p><var class="var">obj</var>: should contain a <code class="code">gnutls_pkcs11_obj_t</code>  type
</p>
<p><var class="var">ptr</var>: will contain the CK_FUNCTION_LIST_PTR pointer (may be <code class="code">NULL</code> )
</p>
<p><var class="var">session</var>: will contain the CK_SESSION_HANDLE of the object
</p>
<p><var class="var">ohandle</var>: will contain the CK_OBJECT_HANDLE of the object
</p>
<p><var class="var">slot_id</var>: the identifier of the slot (may be <code class="code">NULL</code> )
</p>
<p><var class="var">flags</var>: Or sequence of GNUTLS_PKCS11_OBJ_* flags
</p>
<p>Obtains the PKCS<code class="code">11</code>  session handles of an object.  <code class="code">session</code> and  <code class="code">ohandle</code> must be deinitialized by the caller. The returned pointers are
independent of the  <code class="code">obj</code> lifetime.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  (0) on success or a negative error code
on error.
</p>
<p><strong class="strong">Since:</strong> 3.6.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fobj_005fget_005ftype-1"><span>gnutls_pkcs11_obj_get_type<a class="copiable-link" href="#gnutls_005fpkcs11_005fobj_005fget_005ftype-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fobj_005fget_005ftype"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fobj_005fget_005ftype"><span class="category-def">Function: </span><span><code class="def-type">gnutls_pkcs11_obj_type_t</code> <strong class="def-name">gnutls_pkcs11_obj_get_type</strong> <code class="def-code-arguments">(gnutls_pkcs11_obj_t <var class="var">obj</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fobj_005fget_005ftype"> &para;</a></span></dt>
<dd><p><var class="var">obj</var>: Holds the PKCS 11 object
</p>
<p>This function will return the type of the object being
stored in the structure.
</p>
<p><strong class="strong">Returns:</strong> The type of the object
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fobj_005fimport_005furl-1"><span>gnutls_pkcs11_obj_import_url<a class="copiable-link" href="#gnutls_005fpkcs11_005fobj_005fimport_005furl-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fobj_005fimport_005furl"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fobj_005fimport_005furl"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_obj_import_url</strong> <code class="def-code-arguments">(gnutls_pkcs11_obj_t <var class="var">obj</var>, const char * <var class="var">url</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fobj_005fimport_005furl"> &para;</a></span></dt>
<dd><p><var class="var">obj</var>: The structure to store the object
</p>
<p><var class="var">url</var>: a PKCS 11 url identifying the key
</p>
<p><var class="var">flags</var>: Or sequence of GNUTLS_PKCS11_OBJ_* flags
</p>
<p>This function will &quot;import&quot; a PKCS 11 URL identifying an object (e.g. certificate)
to the <code class="code">gnutls_pkcs11_obj_t</code>  type. This does not involve any
parsing (such as X.509 or OpenPGP) since the <code class="code">gnutls_pkcs11_obj_t</code>  is
format agnostic. Only data are transferred.
</p>
<p>If the flag <code class="code">GNUTLS_PKCS11_OBJ_FLAG_OVERWRITE_TRUSTMOD_EXT</code>  is specified
any certificate read, will have its extensions overwritten by any
stapled extensions in the trust module.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fobj_005finit-1"><span>gnutls_pkcs11_obj_init<a class="copiable-link" href="#gnutls_005fpkcs11_005fobj_005finit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fobj_005finit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fobj_005finit"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_obj_init</strong> <code class="def-code-arguments">(gnutls_pkcs11_obj_t * <var class="var">obj</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fobj_005finit"> &para;</a></span></dt>
<dd><p><var class="var">obj</var>: A pointer to the type to be initialized
</p>
<p>This function will initialize a pkcs11 certificate structure.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fobj_005flist_005fimport_005furl3-1"><span>gnutls_pkcs11_obj_list_import_url3<a class="copiable-link" href="#gnutls_005fpkcs11_005fobj_005flist_005fimport_005furl3-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fobj_005flist_005fimport_005furl3"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fobj_005flist_005fimport_005furl3"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_obj_list_import_url3</strong> <code class="def-code-arguments">(gnutls_pkcs11_obj_t * <var class="var">p_list</var>, unsigned int * <var class="var">n_list</var>, const char * <var class="var">url</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fobj_005flist_005fimport_005furl3"> &para;</a></span></dt>
<dd><p><var class="var">p_list</var>: An uninitialized object list (may be <code class="code">NULL</code> )
</p>
<p><var class="var">n_list</var>: Initially should hold the maximum size of the list. Will contain the actual size.
</p>
<p><var class="var">url</var>: A PKCS 11 url identifying a set of objects
</p>
<p><var class="var">flags</var>: Or sequence of GNUTLS_PKCS11_OBJ_* flags
</p>
<p>This function will initialize and set values to an object list
by using all objects identified by a PKCS 11 URL.
</p>
<p>This function will enumerate all the objects specified by the PKCS<code class="code">11</code>  URL
provided. It expects an already allocated  <code class="code">p_list</code> which has * <code class="code">n_list</code> elements,
and that value will be updated to the actual number of present objects. The
 <code class="code">p_list</code> objects will be initialized and set by this function.
To obtain a list of all available objects use a  <code class="code">url</code> of &rsquo;pkcs11:&rsquo;.
</p>
<p>All returned objects must be deinitialized using <code class="code">gnutls_pkcs11_obj_deinit()</code> .
</p>
<p>The supported in this function  <code class="code">flags</code> are <code class="code">GNUTLS_PKCS11_OBJ_FLAG_LOGIN</code> ,
<code class="code">GNUTLS_PKCS11_OBJ_FLAG_LOGIN_SO</code> , <code class="code">GNUTLS_PKCS11_OBJ_FLAG_PRESENT_IN_TRUSTED_MODULE</code> ,
<code class="code">GNUTLS_PKCS11_OBJ_FLAG_CRT</code> , <code class="code">GNUTLS_PKCS11_OBJ_FLAG_PUBKEY</code> , <code class="code">GNUTLS_PKCS11_OBJ_FLAG_PRIVKEY</code> ,
<code class="code">GNUTLS_PKCS11_OBJ_FLAG_WITH_PRIVKEY</code> , <code class="code">GNUTLS_PKCS11_OBJ_FLAG_MARK_CA</code> ,
<code class="code">GNUTLS_PKCS11_OBJ_FLAG_MARK_TRUSTED</code> , and since 3.5.1 the <code class="code">GNUTLS_PKCS11_OBJ_FLAG_OVERWRITE_TRUSTMOD_EXT</code> .
</p>
<p>On versions of GnuTLS prior to 3.4.0 the equivalent function was
<code class="code">gnutls_pkcs11_obj_list_import_url()</code> . That is also available on this version
as a macro which maps to this function.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fobj_005flist_005fimport_005furl4-1"><span>gnutls_pkcs11_obj_list_import_url4<a class="copiable-link" href="#gnutls_005fpkcs11_005fobj_005flist_005fimport_005furl4-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fobj_005flist_005fimport_005furl4"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fobj_005flist_005fimport_005furl4"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_obj_list_import_url4</strong> <code class="def-code-arguments">(gnutls_pkcs11_obj_t ** <var class="var">p_list</var>, unsigned int * <var class="var">n_list</var>, const char * <var class="var">url</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fobj_005flist_005fimport_005furl4"> &para;</a></span></dt>
<dd><p><var class="var">p_list</var>: An uninitialized object list (may be NULL)
</p>
<p><var class="var">n_list</var>: It will contain the size of the list.
</p>
<p><var class="var">url</var>: A PKCS 11 url identifying a set of objects
</p>
<p><var class="var">flags</var>: Or sequence of GNUTLS_PKCS11_OBJ_* flags
</p>
<p>This function will enumerate all the objects specified by the PKCS<code class="code">11</code>  URL
provided. It will initialize and set values to the object pointer list ( <code class="code">p_list</code> )
provided. To obtain a list of all available objects use a  <code class="code">url</code> of &rsquo;pkcs11:&rsquo;.
</p>
<p>All returned objects must be deinitialized using <code class="code">gnutls_pkcs11_obj_deinit()</code> ,
and  <code class="code">p_list</code> must be deinitialized using <code class="code">gnutls_free()</code> .
</p>
<p>The supported in this function  <code class="code">flags</code> are <code class="code">GNUTLS_PKCS11_OBJ_FLAG_LOGIN</code> ,
<code class="code">GNUTLS_PKCS11_OBJ_FLAG_LOGIN_SO</code> , <code class="code">GNUTLS_PKCS11_OBJ_FLAG_PRESENT_IN_TRUSTED_MODULE</code> ,
<code class="code">GNUTLS_PKCS11_OBJ_FLAG_CRT</code> , <code class="code">GNUTLS_PKCS11_OBJ_FLAG_PUBKEY</code> , <code class="code">GNUTLS_PKCS11_OBJ_FLAG_PRIVKEY</code> ,
<code class="code">GNUTLS_PKCS11_OBJ_FLAG_WITH_PRIVKEY</code> , <code class="code">GNUTLS_PKCS11_OBJ_FLAG_MARK_CA</code> ,
<code class="code">GNUTLS_PKCS11_OBJ_FLAG_MARK_TRUSTED</code> , and since 3.5.1 the <code class="code">GNUTLS_PKCS11_OBJ_FLAG_OVERWRITE_TRUSTMOD_EXT</code> .
</p>
<p>On versions of GnuTLS prior to 3.4.0 the equivalent function was
<code class="code">gnutls_pkcs11_obj_list_import_url2()</code> . That is also available on this version
as a macro which maps to this function.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fobj_005fset_005finfo-1"><span>gnutls_pkcs11_obj_set_info<a class="copiable-link" href="#gnutls_005fpkcs11_005fobj_005fset_005finfo-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fobj_005fset_005finfo"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fobj_005fset_005finfo"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_obj_set_info</strong> <code class="def-code-arguments">(gnutls_pkcs11_obj_t <var class="var">obj</var>, gnutls_pkcs11_obj_info_t <var class="var">itype</var>, const void * <var class="var">data</var>, size_t <var class="var">data_size</var>, unsigned <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fobj_005fset_005finfo"> &para;</a></span></dt>
<dd><p><var class="var">obj</var>: should contain a <code class="code">gnutls_pkcs11_obj_t</code>  type
</p>
<p><var class="var">itype</var>: Denotes the type of information to be set
</p>
<p><var class="var">data</var>: the data to set
</p>
<p><var class="var">data_size</var>: the size of data
</p>
<p><var class="var">flags</var>: Or sequence of GNUTLS_PKCS11_OBJ_* flags
</p>
<p>This function will set attributes on the provided object.
Available options for  <code class="code">itype</code> are <code class="code">GNUTLS_PKCS11_OBJ_LABEL</code> ,
<code class="code">GNUTLS_PKCS11_OBJ_ID_HEX</code> , and <code class="code">GNUTLS_PKCS11_OBJ_ID</code> .
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  (0) on success or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fobj_005fset_005fpin_005ffunction-1"><span>gnutls_pkcs11_obj_set_pin_function<a class="copiable-link" href="#gnutls_005fpkcs11_005fobj_005fset_005fpin_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fobj_005fset_005fpin_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fobj_005fset_005fpin_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_pkcs11_obj_set_pin_function</strong> <code class="def-code-arguments">(gnutls_pkcs11_obj_t <var class="var">obj</var>, gnutls_pin_callback_t <var class="var">fn</var>, void * <var class="var">userdata</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fobj_005fset_005fpin_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">obj</var>: The object structure
</p>
<p><var class="var">fn</var>: the callback
</p>
<p><var class="var">userdata</var>: data associated with the callback
</p>
<p>This function will set a callback function to be used when
required to access the object. This function overrides the global
set using <code class="code">gnutls_pkcs11_set_pin_function()</code> .
</p>
<p><strong class="strong">Since:</strong> 3.1.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fprivkey_005fcpy-1"><span>gnutls_pkcs11_privkey_cpy<a class="copiable-link" href="#gnutls_005fpkcs11_005fprivkey_005fcpy-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fprivkey_005fcpy"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fprivkey_005fcpy"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_privkey_cpy</strong> <code class="def-code-arguments">(gnutls_pkcs11_privkey_t <var class="var">dst</var>, gnutls_pkcs11_privkey_t <var class="var">src</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fprivkey_005fcpy"> &para;</a></span></dt>
<dd><p><var class="var">dst</var>: The destination key, which should be initialized.
</p>
<p><var class="var">src</var>: The source key
</p>
<p>This function will copy a private key from source to destination
key. Destination has to be initialized.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fprivkey_005fdeinit-1"><span>gnutls_pkcs11_privkey_deinit<a class="copiable-link" href="#gnutls_005fpkcs11_005fprivkey_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fprivkey_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fprivkey_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_pkcs11_privkey_deinit</strong> <code class="def-code-arguments">(gnutls_pkcs11_privkey_t <var class="var">key</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fprivkey_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: the key to be deinitialized
</p>
<p>This function will deinitialize a private key structure.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fprivkey_005fexport_005fpubkey-1"><span>gnutls_pkcs11_privkey_export_pubkey<a class="copiable-link" href="#gnutls_005fpkcs11_005fprivkey_005fexport_005fpubkey-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fprivkey_005fexport_005fpubkey"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fprivkey_005fexport_005fpubkey"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_privkey_export_pubkey</strong> <code class="def-code-arguments">(gnutls_pkcs11_privkey_t <var class="var">pkey</var>, gnutls_x509_crt_fmt_t <var class="var">fmt</var>, gnutls_datum_t * <var class="var">data</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fprivkey_005fexport_005fpubkey"> &para;</a></span></dt>
<dd><p><var class="var">pkey</var>: The private key
</p>
<p><var class="var">fmt</var>: the format of output params. PEM or DER.
</p>
<p><var class="var">data</var>: will hold the public key
</p>
<p><var class="var">flags</var>: should be zero
</p>
<p>This function will extract the public key (modulus and public
exponent) from the private key specified by the  <code class="code">url</code> private key.
This public key will be stored in  <code class="code">pubkey</code> in the format specified
by  <code class="code">fmt</code> .  <code class="code">pubkey</code> should be deinitialized using <code class="code">gnutls_free()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.7
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fprivkey_005fexport_005furl-1"><span>gnutls_pkcs11_privkey_export_url<a class="copiable-link" href="#gnutls_005fpkcs11_005fprivkey_005fexport_005furl-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fprivkey_005fexport_005furl"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fprivkey_005fexport_005furl"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_privkey_export_url</strong> <code class="def-code-arguments">(gnutls_pkcs11_privkey_t <var class="var">key</var>, gnutls_pkcs11_url_type_t <var class="var">detailed</var>, char ** <var class="var">url</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fprivkey_005fexport_005furl"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: Holds the PKCS 11 key
</p>
<p><var class="var">detailed</var>: non zero if a detailed URL is required
</p>
<p><var class="var">url</var>: will contain an allocated url
</p>
<p>This function will export a URL identifying the given key.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fprivkey_005fgenerate-1"><span>gnutls_pkcs11_privkey_generate<a class="copiable-link" href="#gnutls_005fpkcs11_005fprivkey_005fgenerate-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fprivkey_005fgenerate"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fprivkey_005fgenerate"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_privkey_generate</strong> <code class="def-code-arguments">(const char * <var class="var">url</var>, gnutls_pk_algorithm_t <var class="var">pk</var>, unsigned int <var class="var">bits</var>, const char * <var class="var">label</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fprivkey_005fgenerate"> &para;</a></span></dt>
<dd><p><var class="var">url</var>: a token URL
</p>
<p><var class="var">pk</var>: the public key algorithm
</p>
<p><var class="var">bits</var>: the security bits
</p>
<p><var class="var">label</var>: a label
</p>
<p><var class="var">flags</var>: should be zero
</p>
<p>This function will generate a private key in the specified
by the  <code class="code">url</code> token. The private key will be generate within
the token and will not be exportable.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fprivkey_005fgenerate2-1"><span>gnutls_pkcs11_privkey_generate2<a class="copiable-link" href="#gnutls_005fpkcs11_005fprivkey_005fgenerate2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fprivkey_005fgenerate2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fprivkey_005fgenerate2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_privkey_generate2</strong> <code class="def-code-arguments">(const char * <var class="var">url</var>, gnutls_pk_algorithm_t <var class="var">pk</var>, unsigned int <var class="var">bits</var>, const char * <var class="var">label</var>, gnutls_x509_crt_fmt_t <var class="var">fmt</var>, gnutls_datum_t * <var class="var">pubkey</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fprivkey_005fgenerate2"> &para;</a></span></dt>
<dd><p><var class="var">url</var>: a token URL
</p>
<p><var class="var">pk</var>: the public key algorithm
</p>
<p><var class="var">bits</var>: the security bits
</p>
<p><var class="var">label</var>: a label
</p>
<p><var class="var">fmt</var>: the format of output params. PEM or DER
</p>
<p><var class="var">pubkey</var>: will hold the public key (may be <code class="code">NULL</code> )
</p>
<p><var class="var">flags</var>: zero or an OR&rsquo;ed sequence of <code class="code">GNUTLS_PKCS11_OBJ_FLAGs</code> 
</p>
<p>This function will generate a private key in the specified
by the  <code class="code">url</code> token. The private key will be generate within
the token and will not be exportable. This function will
store the DER-encoded public key in the SubjectPublicKeyInfo format
in  <code class="code">pubkey</code> . The  <code class="code">pubkey</code> should be deinitialized using <code class="code">gnutls_free()</code> .
</p>
<p>Note that when generating an elliptic curve key, the curve
can be substituted in the place of the bits parameter using the
<code class="code">GNUTLS_CURVE_TO_BITS()</code>  macro.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.1.5
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fprivkey_005fgenerate3-1"><span>gnutls_pkcs11_privkey_generate3<a class="copiable-link" href="#gnutls_005fpkcs11_005fprivkey_005fgenerate3-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fprivkey_005fgenerate3"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fprivkey_005fgenerate3"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_privkey_generate3</strong> <code class="def-code-arguments">(const char * <var class="var">url</var>, gnutls_pk_algorithm_t <var class="var">pk</var>, unsigned int <var class="var">bits</var>, const char * <var class="var">label</var>, const gnutls_datum_t * <var class="var">cid</var>, gnutls_x509_crt_fmt_t <var class="var">fmt</var>, gnutls_datum_t * <var class="var">pubkey</var>, unsigned int <var class="var">key_usage</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fprivkey_005fgenerate3"> &para;</a></span></dt>
<dd><p><var class="var">url</var>: a token URL
</p>
<p><var class="var">pk</var>: the public key algorithm
</p>
<p><var class="var">bits</var>: the security bits
</p>
<p><var class="var">label</var>: a label
</p>
<p><var class="var">cid</var>: The CKA_ID to use for the new object
</p>
<p><var class="var">fmt</var>: the format of output params. PEM or DER
</p>
<p><var class="var">pubkey</var>: will hold the public key (may be <code class="code">NULL</code> )
</p>
<p><var class="var">key_usage</var>: One of GNUTLS_KEY_*
</p>
<p><var class="var">flags</var>: zero or an OR&rsquo;ed sequence of <code class="code">GNUTLS_PKCS11_OBJ_FLAGs</code> 
</p>
<p>This function will generate a private key in the specified
by the  <code class="code">url</code> token. The private key will be generate within
the token and will not be exportable. This function will
store the DER-encoded public key in the SubjectPublicKeyInfo format 
in  <code class="code">pubkey</code> . The  <code class="code">pubkey</code> should be deinitialized using <code class="code">gnutls_free()</code> .
</p>
<p>Note that when generating an elliptic curve key, the curve
can be substituted in the place of the bits parameter using the
<code class="code">GNUTLS_CURVE_TO_BITS()</code>  macro.
</p>
<p>Since 3.6.3 the objects are marked as sensitive by default unless
<code class="code">GNUTLS_PKCS11_OBJ_FLAG_MARK_NOT_SENSITIVE</code>  is specified.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fprivkey_005fget_005finfo-1"><span>gnutls_pkcs11_privkey_get_info<a class="copiable-link" href="#gnutls_005fpkcs11_005fprivkey_005fget_005finfo-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fprivkey_005fget_005finfo"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fprivkey_005fget_005finfo"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_privkey_get_info</strong> <code class="def-code-arguments">(gnutls_pkcs11_privkey_t <var class="var">pkey</var>, gnutls_pkcs11_obj_info_t <var class="var">itype</var>, void * <var class="var">output</var>, size_t * <var class="var">output_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fprivkey_005fget_005finfo"> &para;</a></span></dt>
<dd><p><var class="var">pkey</var>: should contain a <code class="code">gnutls_pkcs11_privkey_t</code>  type
</p>
<p><var class="var">itype</var>: Denotes the type of information requested
</p>
<p><var class="var">output</var>: where output will be stored
</p>
<p><var class="var">output_size</var>: contains the maximum size of the output and will be overwritten with actual
</p>
<p>This function will return information about the PKCS 11 private key such
as the label, id as well as token information where the key is stored. When
output is text it returns null terminated string although <code class="code">output_size</code>  contains
the size of the actual data only.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  (0) on success or a negative error code on error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fprivkey_005fget_005fpk_005falgorithm-1"><span>gnutls_pkcs11_privkey_get_pk_algorithm<a class="copiable-link" href="#gnutls_005fpkcs11_005fprivkey_005fget_005fpk_005falgorithm-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fprivkey_005fget_005fpk_005falgorithm"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fprivkey_005fget_005fpk_005falgorithm"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_privkey_get_pk_algorithm</strong> <code class="def-code-arguments">(gnutls_pkcs11_privkey_t <var class="var">key</var>, unsigned int * <var class="var">bits</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fprivkey_005fget_005fpk_005falgorithm"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: should contain a <code class="code">gnutls_pkcs11_privkey_t</code>  type
</p>
<p><var class="var">bits</var>: if bits is non null it will hold the size of the parameters&rsquo; in bits
</p>
<p>This function will return the public key algorithm of a private
key.
</p>
<p><strong class="strong">Returns:</strong> a member of the <code class="code">gnutls_pk_algorithm_t</code>  enumeration on
success, or a negative error code on error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fprivkey_005fimport_005furl-1"><span>gnutls_pkcs11_privkey_import_url<a class="copiable-link" href="#gnutls_005fpkcs11_005fprivkey_005fimport_005furl-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fprivkey_005fimport_005furl"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fprivkey_005fimport_005furl"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_privkey_import_url</strong> <code class="def-code-arguments">(gnutls_pkcs11_privkey_t <var class="var">pkey</var>, const char * <var class="var">url</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fprivkey_005fimport_005furl"> &para;</a></span></dt>
<dd><p><var class="var">pkey</var>: The private key
</p>
<p><var class="var">url</var>: a PKCS 11 url identifying the key
</p>
<p><var class="var">flags</var>: Or sequence of GNUTLS_PKCS11_OBJ_* flags
</p>
<p>This function will &quot;import&quot; a PKCS 11 URL identifying a private
key to the <code class="code">gnutls_pkcs11_privkey_t</code>  type. In reality since
in most cases keys cannot be exported, the private key structure
is being associated with the available operations on the token.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fprivkey_005finit-1"><span>gnutls_pkcs11_privkey_init<a class="copiable-link" href="#gnutls_005fpkcs11_005fprivkey_005finit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fprivkey_005finit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fprivkey_005finit"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_privkey_init</strong> <code class="def-code-arguments">(gnutls_pkcs11_privkey_t * <var class="var">key</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fprivkey_005finit"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: A pointer to the type to be initialized
</p>
<p>This function will initialize an private key structure. This
structure can be used for accessing an underlying PKCS<code class="code">11</code>  object.
</p>
<p>In versions of GnuTLS later than 3.5.11 the object is protected
using locks and a single <code class="code">gnutls_pkcs11_privkey_t</code>  can be re-used
by many threads. However, for performance it is recommended to utilize
one object per key per thread.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fprivkey_005fset_005fpin_005ffunction-1"><span>gnutls_pkcs11_privkey_set_pin_function<a class="copiable-link" href="#gnutls_005fpkcs11_005fprivkey_005fset_005fpin_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fprivkey_005fset_005fpin_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fprivkey_005fset_005fpin_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_pkcs11_privkey_set_pin_function</strong> <code class="def-code-arguments">(gnutls_pkcs11_privkey_t <var class="var">key</var>, gnutls_pin_callback_t <var class="var">fn</var>, void * <var class="var">userdata</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fprivkey_005fset_005fpin_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: The private key
</p>
<p><var class="var">fn</var>: the callback
</p>
<p><var class="var">userdata</var>: data associated with the callback
</p>
<p>This function will set a callback function to be used when
required to access the object. This function overrides the global
set using <code class="code">gnutls_pkcs11_set_pin_function()</code> .
</p>
<p><strong class="strong">Since:</strong> 3.1.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fprivkey_005fstatus-1"><span>gnutls_pkcs11_privkey_status<a class="copiable-link" href="#gnutls_005fpkcs11_005fprivkey_005fstatus-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fprivkey_005fstatus"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fprivkey_005fstatus"><span class="category-def">Function: </span><span><code class="def-type">unsigned</code> <strong class="def-name">gnutls_pkcs11_privkey_status</strong> <code class="def-code-arguments">(gnutls_pkcs11_privkey_t <var class="var">key</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fprivkey_005fstatus"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: Holds the key
</p>
<p>Checks the status of the private key token.
</p>
<p><strong class="strong">Returns:</strong> this function will return non-zero if the token
holding the private key is still available (inserted), and zero otherwise.
</p>
<p><strong class="strong">Since:</strong> 3.1.9
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005freinit-1"><span>gnutls_pkcs11_reinit<a class="copiable-link" href="#gnutls_005fpkcs11_005freinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005freinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005freinit"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_reinit</strong> <code class="def-code-arguments">( <var class="var">void</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005freinit"> &para;</a></span></dt>
<dd>
<p>This function will reinitialize the PKCS 11 subsystem in gnutls. 
This is required by PKCS 11 when an application uses <code class="code">fork()</code> . The
reinitialization function must be called on the child.
</p>
<p>Note that since GnuTLS 3.3.0, the reinitialization of the PKCS <code class="code">11</code> 
subsystem occurs automatically after fork.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fset_005fpin_005ffunction-1"><span>gnutls_pkcs11_set_pin_function<a class="copiable-link" href="#gnutls_005fpkcs11_005fset_005fpin_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fset_005fpin_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fset_005fpin_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_pkcs11_set_pin_function</strong> <code class="def-code-arguments">(gnutls_pin_callback_t <var class="var">fn</var>, void * <var class="var">userdata</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fset_005fpin_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">fn</var>: The PIN callback, a <code class="code">gnutls_pin_callback_t()</code>  function.
</p>
<p><var class="var">userdata</var>: data to be supplied to callback
</p>
<p>This function will set a callback function to be used when a PIN is
required for PKCS 11 operations.  See
<code class="code">gnutls_pin_callback_t()</code>  on how the callback should behave.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005fset_005ftoken_005ffunction-1"><span>gnutls_pkcs11_set_token_function<a class="copiable-link" href="#gnutls_005fpkcs11_005fset_005ftoken_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005fset_005ftoken_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005fset_005ftoken_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_pkcs11_set_token_function</strong> <code class="def-code-arguments">(gnutls_pkcs11_token_callback_t <var class="var">fn</var>, void * <var class="var">userdata</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005fset_005ftoken_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">fn</var>: The token callback
</p>
<p><var class="var">userdata</var>: data to be supplied to callback
</p>
<p>This function will set a callback function to be used when a token
needs to be inserted to continue PKCS 11 operations.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005ftoken_005fcheck_005fmechanism-1"><span>gnutls_pkcs11_token_check_mechanism<a class="copiable-link" href="#gnutls_005fpkcs11_005ftoken_005fcheck_005fmechanism-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005ftoken_005fcheck_005fmechanism"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005ftoken_005fcheck_005fmechanism"><span class="category-def">Function: </span><span><code class="def-type">unsigned</code> <strong class="def-name">gnutls_pkcs11_token_check_mechanism</strong> <code class="def-code-arguments">(const char * <var class="var">url</var>, unsigned long <var class="var">mechanism</var>, void * <var class="var">ptr</var>, unsigned <var class="var">psize</var>, unsigned <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005ftoken_005fcheck_005fmechanism"> &para;</a></span></dt>
<dd><p><var class="var">url</var>: should contain a PKCS 11 URL
</p>
<p><var class="var">mechanism</var>: The PKCS <code class="code">11</code>  mechanism ID
</p>
<p><var class="var">ptr</var>: if set it should point to a CK_MECHANISM_INFO struct
</p>
<p><var class="var">psize</var>: the size of CK_MECHANISM_INFO struct (for safety)
</p>
<p><var class="var">flags</var>: must be zero
</p>
<p>This function will return whether a mechanism is supported
by the given token. If the mechanism is supported and
 <code class="code">ptr</code> is set, it will be updated with the token information.
</p>
<p><strong class="strong">Returns:</strong> Non-zero if the mechanism is supported or zero otherwise.
</p>
<p><strong class="strong">Since:</strong> 3.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005ftoken_005fget_005fflags-1"><span>gnutls_pkcs11_token_get_flags<a class="copiable-link" href="#gnutls_005fpkcs11_005ftoken_005fget_005fflags-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005ftoken_005fget_005fflags"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005ftoken_005fget_005fflags"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_token_get_flags</strong> <code class="def-code-arguments">(const char * <var class="var">url</var>, unsigned int * <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005ftoken_005fget_005fflags"> &para;</a></span></dt>
<dd><p><var class="var">url</var>: should contain a PKCS 11 URL
</p>
<p><var class="var">flags</var>: The output flags (GNUTLS_PKCS11_TOKEN_*)
</p>
<p>This function will return information about the PKCS 11 token flags.
</p>
<p>The supported flags are: <code class="code">GNUTLS_PKCS11_TOKEN_HW</code>  and <code class="code">GNUTLS_PKCS11_TOKEN_TRUSTED</code> .
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  (0) on success or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005ftoken_005fget_005finfo-1"><span>gnutls_pkcs11_token_get_info<a class="copiable-link" href="#gnutls_005fpkcs11_005ftoken_005fget_005finfo-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005ftoken_005fget_005finfo"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005ftoken_005fget_005finfo"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_token_get_info</strong> <code class="def-code-arguments">(const char * <var class="var">url</var>, gnutls_pkcs11_token_info_t <var class="var">ttype</var>, void * <var class="var">output</var>, size_t * <var class="var">output_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005ftoken_005fget_005finfo"> &para;</a></span></dt>
<dd><p><var class="var">url</var>: should contain a PKCS 11 URL
</p>
<p><var class="var">ttype</var>: Denotes the type of information requested
</p>
<p><var class="var">output</var>: where output will be stored
</p>
<p><var class="var">output_size</var>: contains the maximum size of the output buffer and will be
overwritten with the actual size.
</p>
<p>This function will return information about the PKCS 11 token such
as the label, id, etc.
</p>
<p>When output is text, a null terminated string is written to  <code class="code">output</code> and its
string length is written to  <code class="code">output_size</code> (without null terminator). If the
buffer is too small,  <code class="code">output_size</code> will contain the expected buffer size
(with null terminator for text) and return <code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code> .
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  (0) on success or a negative error code
on error.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005ftoken_005fget_005fmechanism-1"><span>gnutls_pkcs11_token_get_mechanism<a class="copiable-link" href="#gnutls_005fpkcs11_005ftoken_005fget_005fmechanism-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005ftoken_005fget_005fmechanism"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005ftoken_005fget_005fmechanism"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_token_get_mechanism</strong> <code class="def-code-arguments">(const char * <var class="var">url</var>, unsigned int <var class="var">idx</var>, unsigned long * <var class="var">mechanism</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005ftoken_005fget_005fmechanism"> &para;</a></span></dt>
<dd><p><var class="var">url</var>: should contain a PKCS 11 URL
</p>
<p><var class="var">idx</var>: The index of the mechanism
</p>
<p><var class="var">mechanism</var>: The PKCS <code class="code">11</code>  mechanism ID
</p>
<p>This function will return the names of the supported mechanisms
by the token. It should be called with an increasing index until
it return GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  (0) on success or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005ftoken_005fget_005fptr-1"><span>gnutls_pkcs11_token_get_ptr<a class="copiable-link" href="#gnutls_005fpkcs11_005ftoken_005fget_005fptr-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005ftoken_005fget_005fptr"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005ftoken_005fget_005fptr-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_token_get_ptr</strong> <code class="def-code-arguments">(const char * <var class="var">url</var>, void ** <var class="var">ptr</var>, unsigned long * <var class="var">slot_id</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005ftoken_005fget_005fptr-1"> &para;</a></span></dt>
<dd><p><var class="var">url</var>: should contain a PKCS<code class="code">11</code>  URL identifying a token
</p>
<p><var class="var">ptr</var>: will contain the CK_FUNCTION_LIST_PTR pointer
</p>
<p><var class="var">slot_id</var>: will contain the slot_id (may be <code class="code">NULL</code> )
</p>
<p><var class="var">flags</var>: should be zero
</p>
<p>This function will return the function pointer of the specified
token by the URL. The returned pointers are valid until
gnutls is deinitialized, c.f. <code class="code">_global_deinit()</code> .
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  (0) on success or a negative error code
on error.
</p>
<p><strong class="strong">Since:</strong> 3.6.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005ftoken_005fget_005frandom-1"><span>gnutls_pkcs11_token_get_random<a class="copiable-link" href="#gnutls_005fpkcs11_005ftoken_005fget_005frandom-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005ftoken_005fget_005frandom"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005ftoken_005fget_005frandom"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_token_get_random</strong> <code class="def-code-arguments">(const char * <var class="var">token_url</var>, void * <var class="var">rnddata</var>, size_t <var class="var">len</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005ftoken_005fget_005frandom"> &para;</a></span></dt>
<dd><p><var class="var">token_url</var>: A PKCS <code class="code">11</code>  URL specifying a token
</p>
<p><var class="var">rnddata</var>: A pointer to the memory area to be filled with random data
</p>
<p><var class="var">len</var>: The number of bytes of randomness to request
</p>
<p>This function will get random data from the given token.
It will store rnddata and fill the memory pointed to by rnddata with
len random bytes from the token.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005ftoken_005fget_005furl-1"><span>gnutls_pkcs11_token_get_url<a class="copiable-link" href="#gnutls_005fpkcs11_005ftoken_005fget_005furl-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005ftoken_005fget_005furl"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005ftoken_005fget_005furl"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_token_get_url</strong> <code class="def-code-arguments">(unsigned int <var class="var">seq</var>, gnutls_pkcs11_url_type_t <var class="var">detailed</var>, char ** <var class="var">url</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005ftoken_005fget_005furl"> &para;</a></span></dt>
<dd><p><var class="var">seq</var>: sequence number starting from 0
</p>
<p><var class="var">detailed</var>: non zero if a detailed URL is required
</p>
<p><var class="var">url</var>: will contain an allocated url
</p>
<p>This function will return the URL for each token available
in system. The url has to be released using <code class="code">gnutls_free()</code> 
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned,
<code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code>  if the sequence number
exceeds the available tokens, otherwise a negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005ftoken_005finit-1"><span>gnutls_pkcs11_token_init<a class="copiable-link" href="#gnutls_005fpkcs11_005ftoken_005finit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005ftoken_005finit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005ftoken_005finit"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_token_init</strong> <code class="def-code-arguments">(const char * <var class="var">token_url</var>, const char * <var class="var">so_pin</var>, const char * <var class="var">label</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005ftoken_005finit"> &para;</a></span></dt>
<dd><p><var class="var">token_url</var>: A PKCS <code class="code">11</code>  URL specifying a token
</p>
<p><var class="var">so_pin</var>: Security Officer&rsquo;s PIN
</p>
<p><var class="var">label</var>: A name to be used for the token, at most 32 characters
</p>
<p>This function will initialize (format) a token. If the token is
at a factory defaults state the security officer&rsquo;s PIN given will be
set to be the default. Otherwise it should match the officer&rsquo;s PIN.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005ftoken_005fset_005fpin-1"><span>gnutls_pkcs11_token_set_pin<a class="copiable-link" href="#gnutls_005fpkcs11_005ftoken_005fset_005fpin-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005ftoken_005fset_005fpin"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005ftoken_005fset_005fpin"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pkcs11_token_set_pin</strong> <code class="def-code-arguments">(const char * <var class="var">token_url</var>, const char * <var class="var">oldpin</var>, const char * <var class="var">newpin</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005ftoken_005fset_005fpin"> &para;</a></span></dt>
<dd><p><var class="var">token_url</var>: A PKCS <code class="code">11</code>  URL specifying a token
</p>
<p><var class="var">oldpin</var>: old user&rsquo;s PIN
</p>
<p><var class="var">newpin</var>: new user&rsquo;s PIN
</p>
<p><var class="var">flags</var>: one of <code class="code">gnutls_pin_flag_t</code> .
</p>
<p>This function will modify or set a user or administrator&rsquo;s PIN for
the given token.  If it is called to set a PIN for first time
the oldpin must be <code class="code">NULL</code> . When setting the admin&rsquo;s PIN with the
<code class="code">GNUTLS_PIN_SO</code>  flag, the  <code class="code">oldpin</code> value must be provided (this requirement
is relaxed after GnuTLS 3.6.5 since which the PIN will be requested if missing).
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpkcs11_005ftype_005fget_005fname-1"><span>gnutls_pkcs11_type_get_name<a class="copiable-link" href="#gnutls_005fpkcs11_005ftype_005fget_005fname-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpkcs11_005ftype_005fget_005fname"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpkcs11_005ftype_005fget_005fname"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_pkcs11_type_get_name</strong> <code class="def-code-arguments">(gnutls_pkcs11_obj_type_t <var class="var">type</var>)</code><a class="copiable-link" href="#index-gnutls_005fpkcs11_005ftype_005fget_005fname"> &para;</a></span></dt>
<dd><p><var class="var">type</var>: Holds the PKCS 11 object type, a <code class="code">gnutls_pkcs11_obj_type_t</code> .
</p>
<p>This function will return a human readable description of the
PKCS11 object type  <code class="code">obj</code> .  It will return &quot;Unknown&quot; for unknown
types.
</p>
<p><strong class="strong">Returns:</strong> human readable string labeling the PKCS11 object type
 <code class="code">type</code> .
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fimport_005fpkcs11-1"><span>gnutls_x509_crt_import_pkcs11<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fimport_005fpkcs11-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fimport_005fpkcs11"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fimport_005fpkcs11"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_import_pkcs11</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, gnutls_pkcs11_obj_t <var class="var">pkcs11_crt</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fimport_005fpkcs11"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: A certificate of type <code class="code">gnutls_x509_crt_t</code> 
</p>
<p><var class="var">pkcs11_crt</var>: A PKCS 11 object that contains a certificate
</p>
<p>This function will import a PKCS 11 certificate to a <code class="code">gnutls_x509_crt_t</code> 
structure.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005flist_005fimport_005fpkcs11-1"><span>gnutls_x509_crt_list_import_pkcs11<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005flist_005fimport_005fpkcs11-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005flist_005fimport_005fpkcs11"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005flist_005fimport_005fpkcs11"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_list_import_pkcs11</strong> <code class="def-code-arguments">(gnutls_x509_crt_t * <var class="var">certs</var>, unsigned int <var class="var">cert_max</var>, gnutls_pkcs11_obj_t *const <var class="var">objs</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005flist_005fimport_005fpkcs11"> &para;</a></span></dt>
<dd><p><var class="var">certs</var>: A list of certificates of type <code class="code">gnutls_x509_crt_t</code> 
</p>
<p><var class="var">cert_max</var>: The maximum size of the list
</p>
<p><var class="var">objs</var>: A list of PKCS 11 objects
</p>
<p><var class="var">flags</var>: 0 for now
</p>
<p>This function will import a PKCS 11 certificate list to a list of 
<code class="code">gnutls_x509_crt_t</code>  type. These must not be initialized.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>


<hr>
</div>
<div class="section-level-extent" id="TPM-API">
<div class="nav-panel">
<p>
Next: <a href="#Abstract-key-API" accesskey="n" rel="next">Abstract key API</a>, Previous: <a href="#PKCS-11-API" accesskey="p" rel="prev">Hardware token via PKCS 11 API</a>, Up: <a href="#API-reference" accesskey="u" rel="up">API reference</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="TPM-API-1"><span>E.8 TPM API<a class="copiable-link" href="#TPM-API-1"> &para;</a></span></h3>

<p>The following functions are to be used for TPM handling.
Their prototypes lie in <samp class="file">gnutls/tpm.h</samp>.
</p>

<h4 class="subheading" id="gnutls_005ftpm_005fget_005fregistered-1"><span>gnutls_tpm_get_registered<a class="copiable-link" href="#gnutls_005ftpm_005fget_005fregistered-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005ftpm_005fget_005fregistered"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ftpm_005fget_005fregistered"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_tpm_get_registered</strong> <code class="def-code-arguments">(gnutls_tpm_key_list_t * <var class="var">list</var>)</code><a class="copiable-link" href="#index-gnutls_005ftpm_005fget_005fregistered"> &para;</a></span></dt>
<dd><p><var class="var">list</var>: a list to store the keys
</p>
<p>This function will get a list of stored keys in the TPM. The uuid
of those keys
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.1.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005ftpm_005fkey_005flist_005fdeinit-1"><span>gnutls_tpm_key_list_deinit<a class="copiable-link" href="#gnutls_005ftpm_005fkey_005flist_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005ftpm_005fkey_005flist_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ftpm_005fkey_005flist_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_tpm_key_list_deinit</strong> <code class="def-code-arguments">(gnutls_tpm_key_list_t <var class="var">list</var>)</code><a class="copiable-link" href="#index-gnutls_005ftpm_005fkey_005flist_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">list</var>: a list of the keys
</p>
<p>This function will deinitialize the list of stored keys in the TPM.
</p>
<p><strong class="strong">Since:</strong> 3.1.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005ftpm_005fkey_005flist_005fget_005furl-1"><span>gnutls_tpm_key_list_get_url<a class="copiable-link" href="#gnutls_005ftpm_005fkey_005flist_005fget_005furl-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005ftpm_005fkey_005flist_005fget_005furl"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ftpm_005fkey_005flist_005fget_005furl"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_tpm_key_list_get_url</strong> <code class="def-code-arguments">(gnutls_tpm_key_list_t <var class="var">list</var>, unsigned int <var class="var">idx</var>, char ** <var class="var">url</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005ftpm_005fkey_005flist_005fget_005furl"> &para;</a></span></dt>
<dd><p><var class="var">list</var>: a list of the keys
</p>
<p><var class="var">idx</var>: The index of the key (starting from zero)
</p>
<p><var class="var">url</var>: The URL to be returned
</p>
<p><var class="var">flags</var>: should be zero
</p>
<p>This function will return for each given index a URL of
the corresponding key.
If the provided index is out of bounds then <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> 
is returned.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.1.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005ftpm_005fprivkey_005fdelete-1"><span>gnutls_tpm_privkey_delete<a class="copiable-link" href="#gnutls_005ftpm_005fprivkey_005fdelete-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005ftpm_005fprivkey_005fdelete"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ftpm_005fprivkey_005fdelete-2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_tpm_privkey_delete</strong> <code class="def-code-arguments">(const char * <var class="var">url</var>, const char * <var class="var">srk_password</var>)</code><a class="copiable-link" href="#index-gnutls_005ftpm_005fprivkey_005fdelete-2"> &para;</a></span></dt>
<dd><p><var class="var">url</var>: the URL describing the key
</p>
<p><var class="var">srk_password</var>: a password for the SRK key
</p>
<p>This function will unregister the private key from the TPM
chip. 
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.1.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005ftpm_005fprivkey_005fgenerate-1"><span>gnutls_tpm_privkey_generate<a class="copiable-link" href="#gnutls_005ftpm_005fprivkey_005fgenerate-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005ftpm_005fprivkey_005fgenerate"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ftpm_005fprivkey_005fgenerate-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_tpm_privkey_generate</strong> <code class="def-code-arguments">(gnutls_pk_algorithm_t <var class="var">pk</var>, unsigned int <var class="var">bits</var>, const char * <var class="var">srk_password</var>, const char * <var class="var">key_password</var>, gnutls_tpmkey_fmt_t <var class="var">format</var>, gnutls_x509_crt_fmt_t <var class="var">pub_format</var>, gnutls_datum_t * <var class="var">privkey</var>, gnutls_datum_t * <var class="var">pubkey</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005ftpm_005fprivkey_005fgenerate-1"> &para;</a></span></dt>
<dd><p><var class="var">pk</var>: the public key algorithm
</p>
<p><var class="var">bits</var>: the security bits
</p>
<p><var class="var">srk_password</var>: a password to protect the exported key (optional)
</p>
<p><var class="var">key_password</var>: the password for the TPM (optional)
</p>
<p><var class="var">format</var>: the format of the private key
</p>
<p><var class="var">pub_format</var>: the format of the public key
</p>
<p><var class="var">privkey</var>: the generated key
</p>
<p><var class="var">pubkey</var>: the corresponding public key (may be null)
</p>
<p><var class="var">flags</var>: should be a list of GNUTLS_TPM_* flags
</p>
<p>This function will generate a private key in the TPM
chip. The private key will be generated within the chip
and will be exported in a wrapped with TPM&rsquo;s master key
form. Furthermore the wrapped key can be protected with
the provided  <code class="code">password</code> .
</p>
<p>Note that bits in TPM is quantized value. If the input value
is not one of the allowed values, then it will be quantized to
one of 512, 1024, 2048, 4096, 8192 and 16384.
</p>
<p>Allowed flags are:
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.1.0
</p></dd></dl>


<hr>
</div>
<div class="section-level-extent" id="Abstract-key-API">
<div class="nav-panel">
<p>
Next: <a href="#Socket-specific-API" accesskey="n" rel="next">Socket specific API</a>, Previous: <a href="#TPM-API" accesskey="p" rel="prev">TPM API</a>, Up: <a href="#API-reference" accesskey="u" rel="up">API reference</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
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<h3 class="section" id="Abstract-key-API-1"><span>E.9 Abstract key API<a class="copiable-link" href="#Abstract-key-API-1"> &para;</a></span></h3>

<p>The following functions are to be used for abstract key handling.
Their prototypes lie in <samp class="file">gnutls/abstract.h</samp>.
</p>

<h4 class="subheading" id="gnutls_005fcertificate_005fset_005fkey-1"><span>gnutls_certificate_set_key<a class="copiable-link" href="#gnutls_005fcertificate_005fset_005fkey-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fset_005fkey"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fset_005fkey-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_certificate_set_key</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">res</var>, const char ** <var class="var">names</var>, int <var class="var">names_size</var>, gnutls_pcert_st * <var class="var">pcert_list</var>, int <var class="var">pcert_list_size</var>, gnutls_privkey_t <var class="var">key</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fset_005fkey-1"> &para;</a></span></dt>
<dd><p><var class="var">res</var>: is a <code class="code">gnutls_certificate_credentials_t</code>  type.
</p>
<p><var class="var">names</var>: is an array of DNS names belonging to the public-key (NULL if none)
</p>
<p><var class="var">names_size</var>: holds the size of the names list
</p>
<p><var class="var">pcert_list</var>: contains a certificate list (chain) or raw public-key
</p>
<p><var class="var">pcert_list_size</var>: holds the size of the certificate list
</p>
<p><var class="var">key</var>: is a <code class="code">gnutls_privkey_t</code>  key corresponding to the first public-key in pcert_list
</p>
<p>This function sets a public/private key pair in the
gnutls_certificate_credentials_t type. The given public key may be encapsulated
in a certificate or can be given as a raw key. This function may be
called more than once, in case multiple key pairs exist for
the server. For clients that want to send more than their own end-
entity certificate (e.g., also an intermediate CA cert), the full
certificate chain must be provided in  <code class="code">pcert_list</code> .
</p>
<p>Note that the  <code class="code">key</code> will become part of the credentials structure and must
not be deallocated. It will be automatically deallocated when the  <code class="code">res</code> structure
is deinitialized.
</p>
<p>If this function fails, the  <code class="code">res</code> structure is at an undefined state and it must
not be reused to load other keys or certificates.
</p>
<p>Note that, this function by default returns zero on success and a negative value on error.
Since 3.5.6, when the flag <code class="code">GNUTLS_CERTIFICATE_API_V2</code>  is set using <code class="code">gnutls_certificate_set_flags()</code> 
it returns an index (greater or equal to zero). That index can be used for other functions to refer to the added key-pair.
</p>
<p>Since GnuTLS 3.6.6 this function also handles raw public keys.
</p>
<p><strong class="strong">Returns:</strong> On success this functions returns zero, and otherwise a negative value on error (see above for modifying that behavior).
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fset_005fretrieve_005ffunction2-1"><span>gnutls_certificate_set_retrieve_function2<a class="copiable-link" href="#gnutls_005fcertificate_005fset_005fretrieve_005ffunction2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fset_005fretrieve_005ffunction2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fset_005fretrieve_005ffunction2"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_certificate_set_retrieve_function2</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">cred</var>, gnutls_certificate_retrieve_function2 * <var class="var">func</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fset_005fretrieve_005ffunction2"> &para;</a></span></dt>
<dd><p><var class="var">cred</var>: is a <code class="code">gnutls_certificate_credentials_t</code>  type.
</p>
<p><var class="var">func</var>: is the callback function
</p>
<p>This function sets a callback to be called in order to retrieve the
certificate to be used in the handshake. The callback will take control
only if a certificate is requested by the peer.
</p>
<p>The callback&rsquo;s function prototype is:
int (*callback)(gnutls_session_t, const gnutls_datum_t* req_ca_dn, int nreqs,
const gnutls_pk_algorithm_t* pk_algos, int pk_algos_length, gnutls_pcert_st** pcert,
unsigned int *pcert_length, gnutls_privkey_t * pkey);
</p>
<p><code class="code">req_ca_dn</code> is only used in X.509 certificates.
Contains a list with the CA names that the server considers trusted.
This is a hint and typically the client should send a certificate that is signed
by one of these CAs. These names, when available, are DER encoded. To get a more
meaningful value use the function <code class="code">gnutls_x509_rdn_get()</code> .
</p>
<p><code class="code">pk_algos</code> contains a list with server&rsquo;s acceptable public key algorithms.
The certificate returned should support the server&rsquo;s given algorithms.
</p>
<p><code class="code">pcert</code> should contain a single certificate and public key or a list of them.
</p>
<p><code class="code">pcert_length</code> is the size of the previous list.
</p>
<p><code class="code">pkey</code> is the private key.
</p>
<p>If the callback function is provided then gnutls will call it, in the
handshake, after the certificate request message has been received.
All the provided by the callback values will not be released or
modified by gnutls.
</p>
<p>In server side pk_algos and req_ca_dn are NULL.
</p>
<p>The callback function should set the certificate list to be sent,
and return 0 on success. If no certificate was selected then the
number of certificates should be set to zero. The value (-1)
indicates error and the handshake will be terminated. If both certificates
are set in the credentials and a callback is available, the callback
takes predence.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcertificate_005fset_005fretrieve_005ffunction3-1"><span>gnutls_certificate_set_retrieve_function3<a class="copiable-link" href="#gnutls_005fcertificate_005fset_005fretrieve_005ffunction3-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcertificate_005fset_005fretrieve_005ffunction3"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcertificate_005fset_005fretrieve_005ffunction3"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_certificate_set_retrieve_function3</strong> <code class="def-code-arguments">(gnutls_certificate_credentials_t <var class="var">cred</var>, gnutls_certificate_retrieve_function3 * <var class="var">func</var>)</code><a class="copiable-link" href="#index-gnutls_005fcertificate_005fset_005fretrieve_005ffunction3"> &para;</a></span></dt>
<dd><p><var class="var">cred</var>: is a <code class="code">gnutls_certificate_credentials_t</code>  type.
</p>
<p><var class="var">func</var>: is the callback function
</p>
<p>This function sets a callback to be called in order to retrieve the
certificate and OCSP responses to be used in the handshake.  <code class="code">func</code> will
be called only if the peer requests a certificate either during handshake
or during post-handshake authentication.
</p>
<p>The callback&rsquo;s function prototype is defined in &lsquo;abstract.h&rsquo;:
</p>
<p>int gnutls_certificate_retrieve_function3(
gnutls_session_t,
const struct gnutls_cert_retr_st *info,
gnutls_pcert_st **certs,
unsigned int *certs_length,
gnutls_ocsp_data_st **ocsp,
unsigned int *ocsp_length,
gnutls_privkey_t *privkey,
unsigned int *flags);
</p>
<p>The info field of the callback contains:
 <code class="code">req_ca_dn</code> which is a list with the CA names that the server considers trusted.
This is a hint and typically the client should send a certificate that is signed
by one of these CAs. These names, when available, are DER encoded. To get a more
meaningful value use the function <code class="code">gnutls_x509_rdn_get()</code> .
 <code class="code">pk_algos</code> contains a list with server&rsquo;s acceptable public key algorithms.
The certificate returned should support the server&rsquo;s given algorithms.
</p>
<p>The callback should fill-in the following values:
</p>
<p><code class="code">certs</code> should contain an allocated list of certificates and public keys.
 <code class="code">certs_length</code> is the size of the previous list.
 <code class="code">ocsp</code> should contain an allocated list of OCSP responses.
 <code class="code">ocsp_length</code> is the size of the previous list.
 <code class="code">privkey</code> is the private key.
</p>
<p>If flags in the callback are set to <code class="code">GNUTLS_CERT_RETR_DEINIT_ALL</code>  then
all provided values must be allocated using <code class="code">gnutls_malloc()</code> , and will
be released by gnutls; otherwise they will not be touched by gnutls.
</p>
<p>The callback function should set the certificate and OCSP response
list to be sent, and return 0 on success. If no certificates are available,
the  <code class="code">certs_length</code> and  <code class="code">ocsp_length</code> should be set to zero. The return
value (-1) indicates error and the handshake will be terminated. If both
certificates are set in the credentials and a callback is available, the
callback takes predence.
</p>
<p>Raw public-keys:
In case raw public-keys are negotiated as certificate type, certificates
that would normally hold the public-key material are not available. In that case,
 <code class="code">certs</code> contains an allocated list with only the public key. Since there is no
certificate, there is also no certificate status. Therefore, OCSP information
should not be set.
</p>
<p><strong class="strong">Since:</strong> 3.6.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpcert_005fdeinit-1"><span>gnutls_pcert_deinit<a class="copiable-link" href="#gnutls_005fpcert_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpcert_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpcert_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_pcert_deinit</strong> <code class="def-code-arguments">(gnutls_pcert_st * <var class="var">pcert</var>)</code><a class="copiable-link" href="#index-gnutls_005fpcert_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">pcert</var>: The structure to be deinitialized
</p>
<p>This function will deinitialize a pcert structure.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpcert_005fexport_005fopenpgp-1"><span>gnutls_pcert_export_openpgp<a class="copiable-link" href="#gnutls_005fpcert_005fexport_005fopenpgp-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpcert_005fexport_005fopenpgp"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpcert_005fexport_005fopenpgp"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pcert_export_openpgp</strong> <code class="def-code-arguments">(gnutls_pcert_st * <var class="var">pcert</var>, gnutls_openpgp_crt_t * <var class="var">crt</var>)</code><a class="copiable-link" href="#index-gnutls_005fpcert_005fexport_005fopenpgp"> &para;</a></span></dt>
<dd><p><var class="var">pcert</var>: The pcert structure.
</p>
<p><var class="var">crt</var>: An initialized <code class="code">gnutls_openpgp_crt_t</code> .
</p>
<p>This function is no-op.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_UNIMPLEMENTED_FEATURE</code> .
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpcert_005fexport_005fx509-1"><span>gnutls_pcert_export_x509<a class="copiable-link" href="#gnutls_005fpcert_005fexport_005fx509-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpcert_005fexport_005fx509"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpcert_005fexport_005fx509"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pcert_export_x509</strong> <code class="def-code-arguments">(gnutls_pcert_st * <var class="var">pcert</var>, gnutls_x509_crt_t * <var class="var">crt</var>)</code><a class="copiable-link" href="#index-gnutls_005fpcert_005fexport_005fx509"> &para;</a></span></dt>
<dd><p><var class="var">pcert</var>: The pcert structure.
</p>
<p><var class="var">crt</var>: An initialized <code class="code">gnutls_x509_crt_t</code> .
</p>
<p>Converts the given <code class="code">gnutls_pcert_t</code>  type into a <code class="code">gnutls_x509_crt_t</code> .
This function only works if the type of  <code class="code">pcert</code> is <code class="code">GNUTLS_CRT_X509</code> .
When successful, the value written to  <code class="code">crt</code> must be freed with
<code class="code">gnutls_x509_crt_deinit()</code>  when no longer needed.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpcert_005fimport_005fopenpgp-1"><span>gnutls_pcert_import_openpgp<a class="copiable-link" href="#gnutls_005fpcert_005fimport_005fopenpgp-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpcert_005fimport_005fopenpgp"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpcert_005fimport_005fopenpgp"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pcert_import_openpgp</strong> <code class="def-code-arguments">(gnutls_pcert_st * <var class="var">pcert</var>, gnutls_openpgp_crt_t <var class="var">crt</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpcert_005fimport_005fopenpgp"> &para;</a></span></dt>
<dd><p><var class="var">pcert</var>: The pcert structure
</p>
<p><var class="var">crt</var>: The raw certificate to be imported
</p>
<p><var class="var">flags</var>: zero for now
</p>
<p>This function is no-op.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_UNIMPLEMENTED_FEATURE</code> .
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpcert_005fimport_005fopenpgp_005fraw-1"><span>gnutls_pcert_import_openpgp_raw<a class="copiable-link" href="#gnutls_005fpcert_005fimport_005fopenpgp_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpcert_005fimport_005fopenpgp_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpcert_005fimport_005fopenpgp_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pcert_import_openpgp_raw</strong> <code class="def-code-arguments">(gnutls_pcert_st * <var class="var">pcert</var>, const gnutls_datum_t * <var class="var">cert</var>, gnutls_openpgp_crt_fmt_t <var class="var">format</var>, gnutls_openpgp_keyid_t <var class="var">keyid</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpcert_005fimport_005fopenpgp_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">pcert</var>: The pcert structure
</p>
<p><var class="var">cert</var>: The raw certificate to be imported
</p>
<p><var class="var">format</var>: The format of the certificate
</p>
<p><var class="var">keyid</var>: The key ID to use (NULL for the master key)
</p>
<p><var class="var">flags</var>: zero for now
</p>
<p>This function is no-op.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_UNIMPLEMENTED_FEATURE</code> .
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpcert_005fimport_005frawpk-1"><span>gnutls_pcert_import_rawpk<a class="copiable-link" href="#gnutls_005fpcert_005fimport_005frawpk-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpcert_005fimport_005frawpk"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpcert_005fimport_005frawpk"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pcert_import_rawpk</strong> <code class="def-code-arguments">(gnutls_pcert_st * <var class="var">pcert</var>, gnutls_pubkey_t <var class="var">pubkey</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpcert_005fimport_005frawpk"> &para;</a></span></dt>
<dd><p><var class="var">pcert</var>: The pcert structure to import the data into.
</p>
<p><var class="var">pubkey</var>: The raw public-key in <code class="code">gnutls_pubkey_t</code>  format to be imported
</p>
<p><var class="var">flags</var>: zero for now
</p>
<p>This convenience function will import (i.e. convert) the given raw
public key  <code class="code">pubkey</code> into a <code class="code">gnutls_pcert_st</code>  structure. The structure
must be deinitialized afterwards using <code class="code">gnutls_pcert_deinit()</code> . The
given  <code class="code">pubkey</code> must not be deinitialized because it will be associated
with the given  <code class="code">pcert</code> structure and will be deinitialized with it.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.6.6
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpcert_005fimport_005frawpk_005fraw-1"><span>gnutls_pcert_import_rawpk_raw<a class="copiable-link" href="#gnutls_005fpcert_005fimport_005frawpk_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpcert_005fimport_005frawpk_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpcert_005fimport_005frawpk_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pcert_import_rawpk_raw</strong> <code class="def-code-arguments">(gnutls_pcert_st * <var class="var">pcert</var>, const gnutls_datum_t * <var class="var">rawpubkey</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, unsigned int <var class="var">key_usage</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpcert_005fimport_005frawpk_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">pcert</var>: The pcert structure to import the data into.
</p>
<p><var class="var">rawpubkey</var>: The raw public-key in <code class="code">gnutls_datum_t</code>  format to be imported.
</p>
<p><var class="var">format</var>: The format of the raw public-key. DER or PEM.
</p>
<p><var class="var">key_usage</var>: An ORed sequence of <code class="code">GNUTLS_KEY_</code> * flags.
</p>
<p><var class="var">flags</var>: zero for now
</p>
<p>This convenience function will import (i.e. convert) the given raw
public key  <code class="code">rawpubkey</code> into a <code class="code">gnutls_pcert_st</code>  structure. The structure
must be deinitialized afterwards using <code class="code">gnutls_pcert_deinit()</code> .
Note that the caller is responsible for freeing  <code class="code">rawpubkey</code> . All necessary
values will be copied into  <code class="code">pcert</code> .
</p>
<p>Key usage (as defined by X.509 extension (2.5.29.15)) can be explicitly
set because there is no certificate structure around the key to define
this value. See for more info <code class="code">gnutls_x509_crt_get_key_usage()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.6.6
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpcert_005fimport_005fx509-1"><span>gnutls_pcert_import_x509<a class="copiable-link" href="#gnutls_005fpcert_005fimport_005fx509-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpcert_005fimport_005fx509"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpcert_005fimport_005fx509"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pcert_import_x509</strong> <code class="def-code-arguments">(gnutls_pcert_st * <var class="var">pcert</var>, gnutls_x509_crt_t <var class="var">crt</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpcert_005fimport_005fx509"> &para;</a></span></dt>
<dd><p><var class="var">pcert</var>: The pcert structure
</p>
<p><var class="var">crt</var>: The certificate to be imported
</p>
<p><var class="var">flags</var>: zero for now
</p>
<p>This convenience function will import the given certificate to a
<code class="code">gnutls_pcert_st</code>  structure. The structure must be deinitialized
afterwards using <code class="code">gnutls_pcert_deinit()</code> ;
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpcert_005fimport_005fx509_005flist-1"><span>gnutls_pcert_import_x509_list<a class="copiable-link" href="#gnutls_005fpcert_005fimport_005fx509_005flist-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpcert_005fimport_005fx509_005flist"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpcert_005fimport_005fx509_005flist"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pcert_import_x509_list</strong> <code class="def-code-arguments">(gnutls_pcert_st * <var class="var">pcert_list</var>, gnutls_x509_crt_t * <var class="var">crt</var>, unsigned * <var class="var">ncrt</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpcert_005fimport_005fx509_005flist"> &para;</a></span></dt>
<dd><p><var class="var">pcert_list</var>: The structures to store the certificates; must not contain initialized <code class="code">gnutls_pcert_st</code>  structures.
</p>
<p><var class="var">crt</var>: The certificates to be imported
</p>
<p><var class="var">ncrt</var>: The number of certificates in  <code class="code">crt</code> ; will be updated if necessary
</p>
<p><var class="var">flags</var>: zero or <code class="code">GNUTLS_X509_CRT_LIST_SORT</code> 
</p>
<p>This convenience function will import the given certificates to an
already allocated set of <code class="code">gnutls_pcert_st</code>  structures. The structures must
be deinitialized afterwards using <code class="code">gnutls_pcert_deinit()</code> .  <code class="code">pcert_list</code> should contain space for at least  <code class="code">ncrt</code> elements.
</p>
<p>In the case <code class="code">GNUTLS_X509_CRT_LIST_SORT</code>  is specified and that
function cannot sort the list, <code class="code">GNUTLS_E_CERTIFICATE_LIST_UNSORTED</code> 
will be returned. Currently sorting can fail if the list size
exceeds an internal constraint (16).
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpcert_005fimport_005fx509_005fraw-1"><span>gnutls_pcert_import_x509_raw<a class="copiable-link" href="#gnutls_005fpcert_005fimport_005fx509_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpcert_005fimport_005fx509_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpcert_005fimport_005fx509_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pcert_import_x509_raw</strong> <code class="def-code-arguments">(gnutls_pcert_st * <var class="var">pcert</var>, const gnutls_datum_t * <var class="var">cert</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpcert_005fimport_005fx509_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">pcert</var>: The pcert structure
</p>
<p><var class="var">cert</var>: The raw certificate to be imported
</p>
<p><var class="var">format</var>: The format of the certificate
</p>
<p><var class="var">flags</var>: zero for now
</p>
<p>This convenience function will import the given certificate to a
<code class="code">gnutls_pcert_st</code>  structure. The structure must be deinitialized
afterwards using <code class="code">gnutls_pcert_deinit()</code> ;
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpcert_005flist_005fimport_005fx509_005ffile-1"><span>gnutls_pcert_list_import_x509_file<a class="copiable-link" href="#gnutls_005fpcert_005flist_005fimport_005fx509_005ffile-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpcert_005flist_005fimport_005fx509_005ffile"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpcert_005flist_005fimport_005fx509_005ffile"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pcert_list_import_x509_file</strong> <code class="def-code-arguments">(gnutls_pcert_st * <var class="var">pcert_list</var>, unsigned * <var class="var">pcert_list_size</var>, const char * <var class="var">file</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, gnutls_pin_callback_t <var class="var">pin_fn</var>, void * <var class="var">pin_fn_userdata</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpcert_005flist_005fimport_005fx509_005ffile"> &para;</a></span></dt>
<dd><p><var class="var">pcert_list</var>: The structures to store the certificates; must not contain initialized <code class="code">gnutls_pcert_st</code>  structures.
</p>
<p><var class="var">pcert_list_size</var>: Initially must hold the maximum number of certs. It will be updated with the number of certs available.
</p>
<p><var class="var">file</var>: A file or supported URI with the certificates to load
</p>
<p><var class="var">format</var>: <code class="code">GNUTLS_X509_FMT_DER</code>  or <code class="code">GNUTLS_X509_FMT_PEM</code>  if a file is given
</p>
<p><var class="var">pin_fn</var>: a PIN callback if not globally set
</p>
<p><var class="var">pin_fn_userdata</var>: parameter for the PIN callback
</p>
<p><var class="var">flags</var>: zero or flags from <code class="code">gnutls_certificate_import_flags</code> 
</p>
<p>This convenience function will import a certificate chain from the given
file or supported URI to <code class="code">gnutls_pcert_st</code>  structures. The structures
must be deinitialized afterwards using <code class="code">gnutls_pcert_deinit()</code> .
</p>
<p>This function will always return a sorted certificate chain.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value; if the  <code class="code">pcert</code> list doesn&rsquo;t have enough space
<code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  will be returned.
</p>
<p><strong class="strong">Since:</strong> 3.6.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpcert_005flist_005fimport_005fx509_005fraw-1"><span>gnutls_pcert_list_import_x509_raw<a class="copiable-link" href="#gnutls_005fpcert_005flist_005fimport_005fx509_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpcert_005flist_005fimport_005fx509_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpcert_005flist_005fimport_005fx509_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pcert_list_import_x509_raw</strong> <code class="def-code-arguments">(gnutls_pcert_st * <var class="var">pcert_list</var>, unsigned int * <var class="var">pcert_list_size</var>, const gnutls_datum_t * <var class="var">data</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpcert_005flist_005fimport_005fx509_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">pcert_list</var>: The structures to store the certificates; must not contain initialized <code class="code">gnutls_pcert_st</code>  structures.
</p>
<p><var class="var">pcert_list_size</var>: Initially must hold the maximum number of certs. It will be updated with the number of certs available.
</p>
<p><var class="var">data</var>: The certificates.
</p>
<p><var class="var">format</var>: One of DER or PEM.
</p>
<p><var class="var">flags</var>: must be (0) or an OR&rsquo;d sequence of gnutls_certificate_import_flags.
</p>
<p>This function will import the provided DER or PEM encoded certificates to an
already allocated set of <code class="code">gnutls_pcert_st</code>  structures. The structures must
be deinitialized afterwards using <code class="code">gnutls_pcert_deinit()</code> .  <code class="code">pcert_list</code> should contain space for at least  <code class="code">pcert_list_size</code> elements.
</p>
<p>If the Certificate is PEM encoded it should have a header of &quot;X509
CERTIFICATE&quot;, or &quot;CERTIFICATE&quot;.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value; if the  <code class="code">pcert</code> list doesn&rsquo;t have enough space
<code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  will be returned.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fdecrypt_005fdata-1"><span>gnutls_privkey_decrypt_data<a class="copiable-link" href="#gnutls_005fprivkey_005fdecrypt_005fdata-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fdecrypt_005fdata"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fdecrypt_005fdata-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_decrypt_data</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">key</var>, unsigned int <var class="var">flags</var>, const gnutls_datum_t * <var class="var">ciphertext</var>, gnutls_datum_t * <var class="var">plaintext</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fdecrypt_005fdata-1"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: Holds the key
</p>
<p><var class="var">flags</var>: zero for now
</p>
<p><var class="var">ciphertext</var>: holds the data to be decrypted
</p>
<p><var class="var">plaintext</var>: will contain the decrypted data, allocated with <code class="code">gnutls_malloc()</code> 
</p>
<p>This function will decrypt the given data using the algorithm
supported by the private key.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fdecrypt_005fdata2-1"><span>gnutls_privkey_decrypt_data2<a class="copiable-link" href="#gnutls_005fprivkey_005fdecrypt_005fdata2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fdecrypt_005fdata2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fdecrypt_005fdata2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_decrypt_data2</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">key</var>, unsigned int <var class="var">flags</var>, const gnutls_datum_t * <var class="var">ciphertext</var>, unsigned char * <var class="var">plaintext</var>, size_t <var class="var">plaintext_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fdecrypt_005fdata2"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: Holds the key
</p>
<p><var class="var">flags</var>: zero for now
</p>
<p><var class="var">ciphertext</var>: holds the data to be decrypted
</p>
<p><var class="var">plaintext</var>: a preallocated buffer that will be filled with the plaintext
</p>
<p><var class="var">plaintext_size</var>: in/out size of the plaintext
</p>
<p>This function will decrypt the given data using the algorithm
supported by the private key. Unlike with <code class="code">gnutls_privkey_decrypt_data()</code> 
this function operates in constant time and constant memory access.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.6.5
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fdeinit-1"><span>gnutls_privkey_deinit<a class="copiable-link" href="#gnutls_005fprivkey_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_privkey_deinit</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">key</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: The key to be deinitialized
</p>
<p>This function will deinitialize a private key structure.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fderive_005fsecret-1"><span>gnutls_privkey_derive_secret<a class="copiable-link" href="#gnutls_005fprivkey_005fderive_005fsecret-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fderive_005fsecret"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fderive_005fsecret"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_derive_secret</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">privkey</var>, gnutls_pubkey_t <var class="var">pubkey</var>, const gnutls_datum_t * <var class="var">nonce</var>, gnutls_datum_t * <var class="var">secret</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fderive_005fsecret"> &para;</a></span></dt>
<dd><p><var class="var">privkey</var>: a private key of type <code class="code">gnutls_privkey_t</code> 
</p>
<p><var class="var">pubkey</var>: a public key of type <code class="code">gnutls_pubkey_t</code> 
</p>
<p><var class="var">nonce</var>: an optional nonce value
</p>
<p><var class="var">secret</var>: where shared secret will be stored
</p>
<p><var class="var">flags</var>: must be zero
</p>
<p>This function will calculate a shared secret from our  <code class="code">privkey</code> and
peer&rsquo;s  <code class="code">pubkey</code> . The result will be stored in  <code class="code">secret</code> , whose data
member should be freed after use using <code class="code">gnutls_free()</code> .  <code class="code">privkey</code> and
 <code class="code">pubkey</code> must be backed by the X.509 keys.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.8.2
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fexport_005fdh_005fraw-1"><span>gnutls_privkey_export_dh_raw<a class="copiable-link" href="#gnutls_005fprivkey_005fexport_005fdh_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fexport_005fdh_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fexport_005fdh_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_export_dh_raw</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">key</var>, gnutls_dh_params_t <var class="var">params</var>, gnutls_datum_t * <var class="var">y</var>, gnutls_datum_t * <var class="var">x</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fexport_005fdh_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: Holds the private key
</p>
<p><var class="var">params</var>: will hold the Diffie-Hellman parameters (optional), must be initialized
</p>
<p><var class="var">y</var>: will hold the y (optional)
</p>
<p><var class="var">x</var>: will hold the x
</p>
<p><var class="var">flags</var>: flags from <code class="code">gnutls_abstract_export_flags_t</code> 
</p>
<p>This function will export the Diffie-Hellman private key parameter
found in the given <code class="code">gnutls_privkey_t</code>  structure. The new parameter
will be allocated using <code class="code">gnutls_malloc()</code>  and will be stored in the
appropriate datum.
</p>
<p>To retrieve other parameters common in both public key and private
key, use <code class="code">gnutls_dh_params_export_raw()</code> .
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.8.2
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fexport_005fdsa_005fraw-1"><span>gnutls_privkey_export_dsa_raw<a class="copiable-link" href="#gnutls_005fprivkey_005fexport_005fdsa_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fexport_005fdsa_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fexport_005fdsa_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_export_dsa_raw</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">key</var>, gnutls_datum_t * <var class="var">p</var>, gnutls_datum_t * <var class="var">q</var>, gnutls_datum_t * <var class="var">g</var>, gnutls_datum_t * <var class="var">y</var>, gnutls_datum_t * <var class="var">x</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fexport_005fdsa_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: Holds the public key
</p>
<p><var class="var">p</var>: will hold the p
</p>
<p><var class="var">q</var>: will hold the q
</p>
<p><var class="var">g</var>: will hold the g
</p>
<p><var class="var">y</var>: will hold the y
</p>
<p><var class="var">x</var>: will hold the x
</p>
<p>This function will export the DSA private key&rsquo;s parameters found
in the given structure. The new parameters will be allocated using
<code class="code">gnutls_malloc()</code>  and will be stored in the appropriate datum.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fexport_005fdsa_005fraw2-1"><span>gnutls_privkey_export_dsa_raw2<a class="copiable-link" href="#gnutls_005fprivkey_005fexport_005fdsa_005fraw2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fexport_005fdsa_005fraw2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fexport_005fdsa_005fraw2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_export_dsa_raw2</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">key</var>, gnutls_datum_t * <var class="var">p</var>, gnutls_datum_t * <var class="var">q</var>, gnutls_datum_t * <var class="var">g</var>, gnutls_datum_t * <var class="var">y</var>, gnutls_datum_t * <var class="var">x</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fexport_005fdsa_005fraw2"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: Holds the public key
</p>
<p><var class="var">p</var>: will hold the p
</p>
<p><var class="var">q</var>: will hold the q
</p>
<p><var class="var">g</var>: will hold the g
</p>
<p><var class="var">y</var>: will hold the y
</p>
<p><var class="var">x</var>: will hold the x
</p>
<p><var class="var">flags</var>: flags from <code class="code">gnutls_abstract_export_flags_t</code> 
</p>
<p>This function will export the DSA private key&rsquo;s parameters found
in the given structure. The new parameters will be allocated using
<code class="code">gnutls_malloc()</code>  and will be stored in the appropriate datum.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fexport_005fecc_005fraw-1"><span>gnutls_privkey_export_ecc_raw<a class="copiable-link" href="#gnutls_005fprivkey_005fexport_005fecc_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fexport_005fecc_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fexport_005fecc_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_export_ecc_raw</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">key</var>, gnutls_ecc_curve_t * <var class="var">curve</var>, gnutls_datum_t * <var class="var">x</var>, gnutls_datum_t * <var class="var">y</var>, gnutls_datum_t * <var class="var">k</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fexport_005fecc_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: Holds the public key
</p>
<p><var class="var">curve</var>: will hold the curve
</p>
<p><var class="var">x</var>: will hold the x-coordinate
</p>
<p><var class="var">y</var>: will hold the y-coordinate
</p>
<p><var class="var">k</var>: will hold the private key
</p>
<p>This function will export the ECC private key&rsquo;s parameters found
in the given structure. The new parameters will be allocated using
<code class="code">gnutls_malloc()</code>  and will be stored in the appropriate datum.
</p>
<p>In EdDSA curves the  <code class="code">y</code> parameter will be <code class="code">NULL</code>  and the other parameters
will be in the native format for the curve.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fexport_005fecc_005fraw2-1"><span>gnutls_privkey_export_ecc_raw2<a class="copiable-link" href="#gnutls_005fprivkey_005fexport_005fecc_005fraw2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fexport_005fecc_005fraw2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fexport_005fecc_005fraw2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_export_ecc_raw2</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">key</var>, gnutls_ecc_curve_t * <var class="var">curve</var>, gnutls_datum_t * <var class="var">x</var>, gnutls_datum_t * <var class="var">y</var>, gnutls_datum_t * <var class="var">k</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fexport_005fecc_005fraw2"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: Holds the public key
</p>
<p><var class="var">curve</var>: will hold the curve
</p>
<p><var class="var">x</var>: will hold the x-coordinate
</p>
<p><var class="var">y</var>: will hold the y-coordinate
</p>
<p><var class="var">k</var>: will hold the private key
</p>
<p><var class="var">flags</var>: flags from <code class="code">gnutls_abstract_export_flags_t</code> 
</p>
<p>This function will export the ECC private key&rsquo;s parameters found
in the given structure. The new parameters will be allocated using
<code class="code">gnutls_malloc()</code>  and will be stored in the appropriate datum.
</p>
<p>In EdDSA curves the  <code class="code">y</code> parameter will be <code class="code">NULL</code>  and the other parameters
will be in the native format for the curve.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fexport_005fgost_005fraw2-1"><span>gnutls_privkey_export_gost_raw2<a class="copiable-link" href="#gnutls_005fprivkey_005fexport_005fgost_005fraw2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fexport_005fgost_005fraw2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fexport_005fgost_005fraw2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_export_gost_raw2</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">key</var>, gnutls_ecc_curve_t * <var class="var">curve</var>, gnutls_digest_algorithm_t * <var class="var">digest</var>, gnutls_gost_paramset_t * <var class="var">paramset</var>, gnutls_datum_t * <var class="var">x</var>, gnutls_datum_t * <var class="var">y</var>, gnutls_datum_t * <var class="var">k</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fexport_005fgost_005fraw2"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: Holds the public key
</p>
<p><var class="var">curve</var>: will hold the curve
</p>
<p><var class="var">digest</var>: will hold the digest
</p>
<p><var class="var">paramset</var>: will hold the GOST parameter set ID
</p>
<p><var class="var">x</var>: will hold the x-coordinate
</p>
<p><var class="var">y</var>: will hold the y-coordinate
</p>
<p><var class="var">k</var>: will hold the private key
</p>
<p><var class="var">flags</var>: flags from <code class="code">gnutls_abstract_export_flags_t</code> 
</p>
<p>This function will export the GOST private key&rsquo;s parameters found
in the given structure. The new parameters will be allocated using
<code class="code">gnutls_malloc()</code>  and will be stored in the appropriate datum.
</p>
<p><strong class="strong">Note:</strong> parameters will be stored with least significant byte first. On
version 3.6.3 this was incorrectly returned in big-endian format.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.6.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fexport_005fopenpgp-1"><span>gnutls_privkey_export_openpgp<a class="copiable-link" href="#gnutls_005fprivkey_005fexport_005fopenpgp-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fexport_005fopenpgp"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fexport_005fopenpgp"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_export_openpgp</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">pkey</var>, gnutls_openpgp_privkey_t * <var class="var">key</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fexport_005fopenpgp"> &para;</a></span></dt>
<dd><p><var class="var">pkey</var>: The private key
</p>
<p><var class="var">key</var>: Location for the key to be exported.
</p>
<p>This function is no-op.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_UNIMPLEMENTED_FEATURE</code> .
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fexport_005fpkcs11-1"><span>gnutls_privkey_export_pkcs11<a class="copiable-link" href="#gnutls_005fprivkey_005fexport_005fpkcs11-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fexport_005fpkcs11"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fexport_005fpkcs11"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_export_pkcs11</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">pkey</var>, gnutls_pkcs11_privkey_t * <var class="var">key</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fexport_005fpkcs11"> &para;</a></span></dt>
<dd><p><var class="var">pkey</var>: The private key
</p>
<p><var class="var">key</var>: Location for the key to be exported.
</p>
<p>Converts the given abstract private key to a <code class="code">gnutls_pkcs11_privkey_t</code> 
type. The key must be of type <code class="code">GNUTLS_PRIVKEY_PKCS11</code> . The key
returned in  <code class="code">key</code> must be deinitialized with
<code class="code">gnutls_pkcs11_privkey_deinit()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fexport_005frsa_005fraw-1"><span>gnutls_privkey_export_rsa_raw<a class="copiable-link" href="#gnutls_005fprivkey_005fexport_005frsa_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fexport_005frsa_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fexport_005frsa_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_export_rsa_raw</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">key</var>, gnutls_datum_t * <var class="var">m</var>, gnutls_datum_t * <var class="var">e</var>, gnutls_datum_t * <var class="var">d</var>, gnutls_datum_t * <var class="var">p</var>, gnutls_datum_t * <var class="var">q</var>, gnutls_datum_t * <var class="var">u</var>, gnutls_datum_t * <var class="var">e1</var>, gnutls_datum_t * <var class="var">e2</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fexport_005frsa_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: Holds the certificate
</p>
<p><var class="var">m</var>: will hold the modulus
</p>
<p><var class="var">e</var>: will hold the public exponent
</p>
<p><var class="var">d</var>: will hold the private exponent
</p>
<p><var class="var">p</var>: will hold the first prime (p)
</p>
<p><var class="var">q</var>: will hold the second prime (q)
</p>
<p><var class="var">u</var>: will hold the coefficient
</p>
<p><var class="var">e1</var>: will hold e1 = d mod (p-1)
</p>
<p><var class="var">e2</var>: will hold e2 = d mod (q-1)
</p>
<p>This function will export the RSA private key&rsquo;s parameters found
in the given structure. The new parameters will be allocated using
<code class="code">gnutls_malloc()</code>  and will be stored in the appropriate datum. For
EdDSA keys, the  <code class="code">y</code> value should be <code class="code">NULL</code> .
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fexport_005frsa_005fraw2-1"><span>gnutls_privkey_export_rsa_raw2<a class="copiable-link" href="#gnutls_005fprivkey_005fexport_005frsa_005fraw2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fexport_005frsa_005fraw2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fexport_005frsa_005fraw2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_export_rsa_raw2</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">key</var>, gnutls_datum_t * <var class="var">m</var>, gnutls_datum_t * <var class="var">e</var>, gnutls_datum_t * <var class="var">d</var>, gnutls_datum_t * <var class="var">p</var>, gnutls_datum_t * <var class="var">q</var>, gnutls_datum_t * <var class="var">u</var>, gnutls_datum_t * <var class="var">e1</var>, gnutls_datum_t * <var class="var">e2</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fexport_005frsa_005fraw2"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: Holds the certificate
</p>
<p><var class="var">m</var>: will hold the modulus
</p>
<p><var class="var">e</var>: will hold the public exponent
</p>
<p><var class="var">d</var>: will hold the private exponent
</p>
<p><var class="var">p</var>: will hold the first prime (p)
</p>
<p><var class="var">q</var>: will hold the second prime (q)
</p>
<p><var class="var">u</var>: will hold the coefficient
</p>
<p><var class="var">e1</var>: will hold e1 = d mod (p-1)
</p>
<p><var class="var">e2</var>: will hold e2 = d mod (q-1)
</p>
<p><var class="var">flags</var>: flags from <code class="code">gnutls_abstract_export_flags_t</code> 
</p>
<p>This function will export the RSA private key&rsquo;s parameters found
in the given structure. The new parameters will be allocated using
<code class="code">gnutls_malloc()</code>  and will be stored in the appropriate datum.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fexport_005fx509-1"><span>gnutls_privkey_export_x509<a class="copiable-link" href="#gnutls_005fprivkey_005fexport_005fx509-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fexport_005fx509"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fexport_005fx509"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_export_x509</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">pkey</var>, gnutls_x509_privkey_t * <var class="var">key</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fexport_005fx509"> &para;</a></span></dt>
<dd><p><var class="var">pkey</var>: The private key
</p>
<p><var class="var">key</var>: Location for the key to be exported.
</p>
<p>Converts the given abstract private key to a <code class="code">gnutls_x509_privkey_t</code> 
type. The abstract key must be of type <code class="code">GNUTLS_PRIVKEY_X509</code> . The input
 <code class="code">key</code> must not be initialized. The key returned in  <code class="code">key</code> should be deinitialized
using <code class="code">gnutls_x509_privkey_deinit()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fgenerate-1"><span>gnutls_privkey_generate<a class="copiable-link" href="#gnutls_005fprivkey_005fgenerate-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fgenerate"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fgenerate"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_generate</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">pkey</var>, gnutls_pk_algorithm_t <var class="var">algo</var>, unsigned int <var class="var">bits</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fgenerate"> &para;</a></span></dt>
<dd><p><var class="var">pkey</var>: An initialized private key
</p>
<p><var class="var">algo</var>: is one of the algorithms in <code class="code">gnutls_pk_algorithm_t</code> .
</p>
<p><var class="var">bits</var>: the size of the parameters to generate
</p>
<p><var class="var">flags</var>: Must be zero or flags from <code class="code">gnutls_privkey_flags_t</code> .
</p>
<p>This function will generate a random private key. Note that this
function must be called on an initialized private key.
</p>
<p>The flag <code class="code">GNUTLS_PRIVKEY_FLAG_PROVABLE</code> 
instructs the key generation process to use algorithms like Shawe-Taylor
(from FIPS PUB186-4) which generate provable parameters out of a seed
for RSA and DSA keys. See <code class="code">gnutls_privkey_generate2()</code>  for more
information.
</p>
<p>Note that when generating an elliptic curve key, the curve
can be substituted in the place of the bits parameter using the
<code class="code">GNUTLS_CURVE_TO_BITS()</code>  macro. The input to the macro is any curve from
<code class="code">gnutls_ecc_curve_t</code> .
</p>
<p>For DSA keys, if the subgroup size needs to be specified check
the <code class="code">GNUTLS_SUBGROUP_TO_BITS()</code>  macro.
</p>
<p>It is recommended to do not set the number of  <code class="code">bits</code> directly, use <code class="code">gnutls_sec_param_to_pk_bits()</code>  instead .
</p>
<p>See also <code class="code">gnutls_privkey_generate2()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fgenerate2-1"><span>gnutls_privkey_generate2<a class="copiable-link" href="#gnutls_005fprivkey_005fgenerate2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fgenerate2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fgenerate2-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_generate2</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">pkey</var>, gnutls_pk_algorithm_t <var class="var">algo</var>, unsigned int <var class="var">bits</var>, unsigned int <var class="var">flags</var>, const gnutls_keygen_data_st * <var class="var">data</var>, unsigned <var class="var">data_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fgenerate2-1"> &para;</a></span></dt>
<dd><p><var class="var">pkey</var>: The private key
</p>
<p><var class="var">algo</var>: is one of the algorithms in <code class="code">gnutls_pk_algorithm_t</code> .
</p>
<p><var class="var">bits</var>: the size of the modulus
</p>
<p><var class="var">flags</var>: Must be zero or flags from <code class="code">gnutls_privkey_flags_t</code> .
</p>
<p><var class="var">data</var>: Allow specifying <code class="code">gnutls_keygen_data_st</code>  types such as the seed to be used.
</p>
<p><var class="var">data_size</var>: The number of  <code class="code">data</code> available.
</p>
<p>This function will generate a random private key. Note that this
function must be called on an initialized private key.
</p>
<p>The flag <code class="code">GNUTLS_PRIVKEY_FLAG_PROVABLE</code> 
instructs the key generation process to use algorithms like Shawe-Taylor
(from FIPS PUB186-4) which generate provable parameters out of a seed
for RSA and DSA keys. On DSA keys the PQG parameters are generated using the
seed, while on RSA the two primes. To specify an explicit seed
(by default a random seed is used), use the  <code class="code">data</code> with a <code class="code">GNUTLS_KEYGEN_SEED</code> 
type.
</p>
<p>Note that when generating an elliptic curve key, the curve
can be substituted in the place of the bits parameter using the
<code class="code">GNUTLS_CURVE_TO_BITS()</code>  macro.
</p>
<p>To export the generated keys in memory or in files it is recommended to use the
PKCS<code class="code">8</code>  form as it can handle all key types, and can store additional parameters
such as the seed, in case of provable RSA or DSA keys.
Generated keys can be exported in memory using <code class="code">gnutls_privkey_export_x509()</code> ,
and then with <code class="code">gnutls_x509_privkey_export2_pkcs8()</code> .
</p>
<p>If key generation is part of your application, avoid setting the number
of bits directly, and instead use <code class="code">gnutls_sec_param_to_pk_bits()</code> .
That way the generated keys will adapt to the security levels
of the underlying GnuTLS library.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.5.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fget_005fpk_005falgorithm-1"><span>gnutls_privkey_get_pk_algorithm<a class="copiable-link" href="#gnutls_005fprivkey_005fget_005fpk_005falgorithm-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fget_005fpk_005falgorithm"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fget_005fpk_005falgorithm"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_get_pk_algorithm</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">key</var>, unsigned int * <var class="var">bits</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fget_005fpk_005falgorithm"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: should contain a <code class="code">gnutls_privkey_t</code>  type
</p>
<p><var class="var">bits</var>: If set will return the number of bits of the parameters (may be NULL)
</p>
<p>This function will return the public key algorithm of a private
key and if possible will return a number of bits that indicates
the security parameter of the key.
</p>
<p><strong class="strong">Returns:</strong> a member of the <code class="code">gnutls_pk_algorithm_t</code>  enumeration on
success, or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fget_005fseed-1"><span>gnutls_privkey_get_seed<a class="copiable-link" href="#gnutls_005fprivkey_005fget_005fseed-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fget_005fseed"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fget_005fseed"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_get_seed</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">key</var>, gnutls_digest_algorithm_t * <var class="var">digest</var>, void * <var class="var">seed</var>, size_t * <var class="var">seed_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fget_005fseed"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: should contain a <code class="code">gnutls_privkey_t</code>  type
</p>
<p><var class="var">digest</var>: if non-NULL it will contain the digest algorithm used for key generation (if applicable)
</p>
<p><var class="var">seed</var>: where seed will be copied to
</p>
<p><var class="var">seed_size</var>: originally holds the size of  <code class="code">seed</code> , will be updated with actual size
</p>
<p>This function will return the seed that was used to generate the
given private key. That function will succeed only if the key was generated
as a provable key.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.5.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fget_005fspki-1"><span>gnutls_privkey_get_spki<a class="copiable-link" href="#gnutls_005fprivkey_005fget_005fspki-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fget_005fspki"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fget_005fspki"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_get_spki</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">privkey</var>, gnutls_x509_spki_t <var class="var">spki</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fget_005fspki"> &para;</a></span></dt>
<dd><p><var class="var">privkey</var>: a public key of type <code class="code">gnutls_privkey_t</code> 
</p>
<p><var class="var">spki</var>: a SubjectPublicKeyInfo structure of type <code class="code">gnutls_privkey_spki_t</code> 
</p>
<p><var class="var">flags</var>: must be zero
</p>
<p>This function will return the public key information if available.
The provided  <code class="code">spki</code> must be initialized.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fget_005ftype-1"><span>gnutls_privkey_get_type<a class="copiable-link" href="#gnutls_005fprivkey_005fget_005ftype-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fget_005ftype"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fget_005ftype"><span class="category-def">Function: </span><span><code class="def-type">gnutls_privkey_type_t</code> <strong class="def-name">gnutls_privkey_get_type</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">key</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fget_005ftype"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: should contain a <code class="code">gnutls_privkey_t</code>  type
</p>
<p>This function will return the type of the private key. This is
actually the type of the subsystem used to set this private key.
</p>
<p><strong class="strong">Returns:</strong> a member of the <code class="code">gnutls_privkey_type_t</code>  enumeration on
success, or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fimport_005fdh_005fraw-1"><span>gnutls_privkey_import_dh_raw<a class="copiable-link" href="#gnutls_005fprivkey_005fimport_005fdh_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fimport_005fdh_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fimport_005fdh_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_import_dh_raw</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">key</var>, const gnutls_dh_params_t <var class="var">params</var>, const gnutls_datum_t * <var class="var">y</var>, const gnutls_datum_t * <var class="var">x</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fimport_005fdh_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: The structure to store the parsed key
</p>
<p><var class="var">params</var>: holds the <code class="code">gnutls_dh_params_t</code> 
</p>
<p><var class="var">y</var>: holds the y (optional)
</p>
<p><var class="var">x</var>: holds the x
</p>
<p>This function will convert the given Diffie-Hellman raw parameters
to the native <code class="code">gnutls_privkey_t</code>  format.  The output will be stored
in  <code class="code">key</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.8.2
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fimport_005fdsa_005fraw-1"><span>gnutls_privkey_import_dsa_raw<a class="copiable-link" href="#gnutls_005fprivkey_005fimport_005fdsa_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fimport_005fdsa_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fimport_005fdsa_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_import_dsa_raw</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">key</var>, const gnutls_datum_t * <var class="var">p</var>, const gnutls_datum_t * <var class="var">q</var>, const gnutls_datum_t * <var class="var">g</var>, const gnutls_datum_t * <var class="var">y</var>, const gnutls_datum_t * <var class="var">x</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fimport_005fdsa_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: The structure to store the parsed key
</p>
<p><var class="var">p</var>: holds the p
</p>
<p><var class="var">q</var>: holds the q
</p>
<p><var class="var">g</var>: holds the g
</p>
<p><var class="var">y</var>: holds the y (optional)
</p>
<p><var class="var">x</var>: holds the x
</p>
<p>This function will convert the given DSA raw parameters to the
native <code class="code">gnutls_privkey_t</code>  format.  The output will be stored
in  <code class="code">key</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fimport_005fecc_005fraw-1"><span>gnutls_privkey_import_ecc_raw<a class="copiable-link" href="#gnutls_005fprivkey_005fimport_005fecc_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fimport_005fecc_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fimport_005fecc_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_import_ecc_raw</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">key</var>, gnutls_ecc_curve_t <var class="var">curve</var>, const gnutls_datum_t * <var class="var">x</var>, const gnutls_datum_t * <var class="var">y</var>, const gnutls_datum_t * <var class="var">k</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fimport_005fecc_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: The key
</p>
<p><var class="var">curve</var>: holds the curve
</p>
<p><var class="var">x</var>: holds the x-coordinate
</p>
<p><var class="var">y</var>: holds the y-coordinate
</p>
<p><var class="var">k</var>: holds the k (private key)
</p>
<p>This function will convert the given elliptic curve parameters to the
native <code class="code">gnutls_privkey_t</code>  format.  The output will be stored
in  <code class="code">key</code> .
</p>
<p>In EdDSA curves the  <code class="code">y</code> parameter should be <code class="code">NULL</code>  and the  <code class="code">x</code> and  <code class="code">k</code> parameters
must be in the native format for the curve.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fimport_005fext-1"><span>gnutls_privkey_import_ext<a class="copiable-link" href="#gnutls_005fprivkey_005fimport_005fext-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fimport_005fext"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fimport_005fext"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_import_ext</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">pkey</var>, gnutls_pk_algorithm_t <var class="var">pk</var>, void * <var class="var">userdata</var>, gnutls_privkey_sign_func <var class="var">sign_func</var>, gnutls_privkey_decrypt_func <var class="var">decrypt_func</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fimport_005fext"> &para;</a></span></dt>
<dd><p><var class="var">pkey</var>: The private key
</p>
<p><var class="var">pk</var>: The public key algorithm
</p>
<p><var class="var">userdata</var>: private data to be provided to the callbacks
</p>
<p><var class="var">sign_func</var>: callback for signature operations
</p>
<p><var class="var">decrypt_func</var>: callback for decryption operations
</p>
<p><var class="var">flags</var>: Flags for the import
</p>
<p>This function will associate the given callbacks with the
<code class="code">gnutls_privkey_t</code>  type. At least one of the two callbacks
must be non-null.
</p>
<p>Note that the signing function is supposed to &quot;raw&quot; sign data, i.e.,
without any hashing or preprocessing. In case of RSA the DigestInfo
will be provided, and the signing function is expected to do the PKCS <code class="code">1</code> 
1.5 padding and the exponentiation.
</p>
<p>See also <code class="code">gnutls_privkey_import_ext3()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fimport_005fext2-1"><span>gnutls_privkey_import_ext2<a class="copiable-link" href="#gnutls_005fprivkey_005fimport_005fext2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fimport_005fext2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fimport_005fext2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_import_ext2</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">pkey</var>, gnutls_pk_algorithm_t <var class="var">pk</var>, void * <var class="var">userdata</var>, gnutls_privkey_sign_func <var class="var">sign_fn</var>, gnutls_privkey_decrypt_func <var class="var">decrypt_fn</var>, gnutls_privkey_deinit_func <var class="var">deinit_fn</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fimport_005fext2"> &para;</a></span></dt>
<dd><p><var class="var">pkey</var>: The private key
</p>
<p><var class="var">pk</var>: The public key algorithm
</p>
<p><var class="var">userdata</var>: private data to be provided to the callbacks
</p>
<p><var class="var">sign_fn</var>: callback for signature operations
</p>
<p><var class="var">decrypt_fn</var>: callback for decryption operations
</p>
<p><var class="var">deinit_fn</var>: a deinitialization function
</p>
<p><var class="var">flags</var>: Flags for the import
</p>
<p>This function will associate the given callbacks with the
<code class="code">gnutls_privkey_t</code>  type. At least one of the two callbacks
must be non-null. If a deinitialization function is provided
then flags is assumed to contain <code class="code">GNUTLS_PRIVKEY_IMPORT_AUTO_RELEASE</code> .
</p>
<p>Note that the signing function is supposed to &quot;raw&quot; sign data, i.e.,
without any hashing or preprocessing. In case of RSA the DigestInfo
will be provided, and the signing function is expected to do the PKCS <code class="code">1</code> 
1.5 padding and the exponentiation.
</p>
<p>See also <code class="code">gnutls_privkey_import_ext3()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.1
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fimport_005fext3-1"><span>gnutls_privkey_import_ext3<a class="copiable-link" href="#gnutls_005fprivkey_005fimport_005fext3-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fimport_005fext3"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fimport_005fext3"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_import_ext3</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">pkey</var>, void * <var class="var">userdata</var>, gnutls_privkey_sign_func <var class="var">sign_fn</var>, gnutls_privkey_decrypt_func <var class="var">decrypt_fn</var>, gnutls_privkey_deinit_func <var class="var">deinit_fn</var>, gnutls_privkey_info_func <var class="var">info_fn</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fimport_005fext3"> &para;</a></span></dt>
<dd><p><var class="var">pkey</var>: The private key
</p>
<p><var class="var">userdata</var>: private data to be provided to the callbacks
</p>
<p><var class="var">sign_fn</var>: callback for signature operations
</p>
<p><var class="var">decrypt_fn</var>: callback for decryption operations
</p>
<p><var class="var">deinit_fn</var>: a deinitialization function
</p>
<p><var class="var">info_fn</var>: returns info about the public key algorithm (should not be <code class="code">NULL</code> )
</p>
<p><var class="var">flags</var>: Flags for the import
</p>
<p>This function will associate the given callbacks with the
<code class="code">gnutls_privkey_t</code>  type. At least one of the two callbacks
must be non-null. If a deinitialization function is provided
then flags is assumed to contain <code class="code">GNUTLS_PRIVKEY_IMPORT_AUTO_RELEASE</code> .
</p>
<p>Note that the signing function is supposed to &quot;raw&quot; sign data, i.e.,
without any hashing or preprocessing. In case of RSA the DigestInfo
will be provided, and the signing function is expected to do the PKCS <code class="code">1</code> 
1.5 padding and the exponentiation.
</p>
<p>The  <code class="code">info_fn</code> must provide information on the algorithms supported by
this private key, and should support the flags <code class="code">GNUTLS_PRIVKEY_INFO_PK_ALGO</code>  and
<code class="code">GNUTLS_PRIVKEY_INFO_SIGN_ALGO</code> . It must return -1 on unknown flags.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fimport_005fext4-1"><span>gnutls_privkey_import_ext4<a class="copiable-link" href="#gnutls_005fprivkey_005fimport_005fext4-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fimport_005fext4"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fimport_005fext4-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_import_ext4</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">pkey</var>, void * <var class="var">userdata</var>, gnutls_privkey_sign_data_func <var class="var">sign_data_fn</var>, gnutls_privkey_sign_hash_func <var class="var">sign_hash_fn</var>, gnutls_privkey_decrypt_func <var class="var">decrypt_fn</var>, gnutls_privkey_deinit_func <var class="var">deinit_fn</var>, gnutls_privkey_info_func <var class="var">info_fn</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fimport_005fext4-1"> &para;</a></span></dt>
<dd><p><var class="var">pkey</var>: The private key
</p>
<p><var class="var">userdata</var>: private data to be provided to the callbacks
</p>
<p><var class="var">sign_data_fn</var>: callback for signature operations (may be <code class="code">NULL</code> )
</p>
<p><var class="var">sign_hash_fn</var>: callback for signature operations (may be <code class="code">NULL</code> )
</p>
<p><var class="var">decrypt_fn</var>: callback for decryption operations (may be <code class="code">NULL</code> )
</p>
<p><var class="var">deinit_fn</var>: a deinitialization function
</p>
<p><var class="var">info_fn</var>: returns info about the public key algorithm (should not be <code class="code">NULL</code> )
</p>
<p><var class="var">flags</var>: Flags for the import
</p>
<p>This function will associate the given callbacks with the
<code class="code">gnutls_privkey_t</code>  type. At least one of the callbacks
must be non-null. If a deinitialization function is provided
then flags is assumed to contain <code class="code">GNUTLS_PRIVKEY_IMPORT_AUTO_RELEASE</code> .
</p>
<p>Note that in contrast with the signing function of
<code class="code">gnutls_privkey_import_ext3()</code> , the signing functions provided to this
function take explicitly the signature algorithm as parameter and
different functions are provided to sign the data and hashes.
</p>
<p>The  <code class="code">sign_hash_fn</code> is to be called to sign pre-hashed data. The input
to the callback is the output of the hash (such as SHA256) corresponding
to the signature algorithm. For RSA PKCS<code class="code">1</code>  signatures, the signature
algorithm can be set to <code class="code">GNUTLS_SIGN_RSA_RAW</code> , and in that case the data
should be handled as if they were an RSA PKCS<code class="code">1</code>  DigestInfo structure.
</p>
<p>The  <code class="code">sign_data_fn</code> is to be called to sign data. The input data will be
he data to be signed (and hashed), with the provided signature
algorithm. This function is to be used for signature algorithms like
Ed25519 which cannot take pre-hashed data as input.
</p>
<p>When both  <code class="code">sign_data_fn</code> and  <code class="code">sign_hash_fn</code> functions are provided they
must be able to operate on all the supported signature algorithms,
unless prohibited by the type of the algorithm (e.g., as with Ed25519).
</p>
<p>The  <code class="code">info_fn</code> must provide information on the signature algorithms supported by
this private key, and should support the flags <code class="code">GNUTLS_PRIVKEY_INFO_PK_ALGO</code> ,
<code class="code">GNUTLS_PRIVKEY_INFO_HAVE_SIGN_ALGO</code>  and <code class="code">GNUTLS_PRIVKEY_INFO_PK_ALGO_BITS</code> .
It must return -1 on unknown flags.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fimport_005fgost_005fraw-1"><span>gnutls_privkey_import_gost_raw<a class="copiable-link" href="#gnutls_005fprivkey_005fimport_005fgost_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fimport_005fgost_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fimport_005fgost_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_import_gost_raw</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">key</var>, gnutls_ecc_curve_t <var class="var">curve</var>, gnutls_digest_algorithm_t <var class="var">digest</var>, gnutls_gost_paramset_t <var class="var">paramset</var>, const gnutls_datum_t * <var class="var">x</var>, const gnutls_datum_t * <var class="var">y</var>, const gnutls_datum_t * <var class="var">k</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fimport_005fgost_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: The key
</p>
<p><var class="var">curve</var>: holds the curve
</p>
<p><var class="var">digest</var>: holds the digest
</p>
<p><var class="var">paramset</var>: holds the GOST parameter set ID
</p>
<p><var class="var">x</var>: holds the x-coordinate
</p>
<p><var class="var">y</var>: holds the y-coordinate
</p>
<p><var class="var">k</var>: holds the k (private key)
</p>
<p>This function will convert the given GOST private key&rsquo;s parameters to the
native <code class="code">gnutls_privkey_t</code>  format.  The output will be stored
in  <code class="code">key</code> .   <code class="code">digest</code> should be one of GNUTLS_DIG_GOSR_94,
GNUTLS_DIG_STREEBOG_256 or GNUTLS_DIG_STREEBOG_512.  If  <code class="code">paramset</code> is set to
GNUTLS_GOST_PARAMSET_UNKNOWN default one will be selected depending on
 <code class="code">digest</code> .
</p>
<p><strong class="strong">Note:</strong> parameters should be stored with least significant byte first. On
version 3.6.3 big-endian format was used incorrectly.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.6.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fimport_005fopenpgp-1"><span>gnutls_privkey_import_openpgp<a class="copiable-link" href="#gnutls_005fprivkey_005fimport_005fopenpgp-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fimport_005fopenpgp"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fimport_005fopenpgp"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_import_openpgp</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">pkey</var>, gnutls_openpgp_privkey_t <var class="var">key</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fimport_005fopenpgp"> &para;</a></span></dt>
<dd><p><var class="var">pkey</var>: The private key
</p>
<p><var class="var">key</var>: The private key to be imported
</p>
<p><var class="var">flags</var>: Flags for the import
</p>
<p>This function is no-op.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_UNIMPLEMENTED_FEATURE</code> .
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fimport_005fopenpgp_005fraw-1"><span>gnutls_privkey_import_openpgp_raw<a class="copiable-link" href="#gnutls_005fprivkey_005fimport_005fopenpgp_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fimport_005fopenpgp_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fimport_005fopenpgp_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_import_openpgp_raw</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">pkey</var>, const gnutls_datum_t * <var class="var">data</var>, gnutls_openpgp_crt_fmt_t <var class="var">format</var>, const gnutls_openpgp_keyid_t <var class="var">keyid</var>, const char * <var class="var">password</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fimport_005fopenpgp_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">pkey</var>: The private key
</p>
<p><var class="var">data</var>: The private key data to be imported
</p>
<p><var class="var">format</var>: The format of the private key
</p>
<p><var class="var">keyid</var>: The key id to use (optional)
</p>
<p><var class="var">password</var>: A password (optional)
</p>
<p>This function is no-op.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_UNIMPLEMENTED_FEATURE</code> .
</p>
<p><strong class="strong">Since:</strong> 3.1.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fimport_005fpkcs11-1"><span>gnutls_privkey_import_pkcs11<a class="copiable-link" href="#gnutls_005fprivkey_005fimport_005fpkcs11-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fimport_005fpkcs11"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fimport_005fpkcs11"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_import_pkcs11</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">pkey</var>, gnutls_pkcs11_privkey_t <var class="var">key</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fimport_005fpkcs11"> &para;</a></span></dt>
<dd><p><var class="var">pkey</var>: The private key
</p>
<p><var class="var">key</var>: The private key to be imported
</p>
<p><var class="var">flags</var>: Flags for the import
</p>
<p>This function will import the given private key to the abstract
<code class="code">gnutls_privkey_t</code>  type.
</p>
<p>The <code class="code">gnutls_pkcs11_privkey_t</code>  object must not be deallocated
during the lifetime of this structure.
</p>
<p><code class="code">flags</code> might be zero or one of <code class="code">GNUTLS_PRIVKEY_IMPORT_AUTO_RELEASE</code> 
and <code class="code">GNUTLS_PRIVKEY_IMPORT_COPY</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fimport_005fpkcs11_005furl-1"><span>gnutls_privkey_import_pkcs11_url<a class="copiable-link" href="#gnutls_005fprivkey_005fimport_005fpkcs11_005furl-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fimport_005fpkcs11_005furl"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fimport_005fpkcs11_005furl"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_import_pkcs11_url</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">key</var>, const char * <var class="var">url</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fimport_005fpkcs11_005furl"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: A key of type <code class="code">gnutls_pubkey_t</code> 
</p>
<p><var class="var">url</var>: A PKCS 11 url
</p>
<p>This function will import a PKCS 11 private key to a <code class="code">gnutls_privkey_t</code> 
type.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.1.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fimport_005frsa_005fraw-1"><span>gnutls_privkey_import_rsa_raw<a class="copiable-link" href="#gnutls_005fprivkey_005fimport_005frsa_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fimport_005frsa_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fimport_005frsa_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_import_rsa_raw</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">key</var>, const gnutls_datum_t * <var class="var">m</var>, const gnutls_datum_t * <var class="var">e</var>, const gnutls_datum_t * <var class="var">d</var>, const gnutls_datum_t * <var class="var">p</var>, const gnutls_datum_t * <var class="var">q</var>, const gnutls_datum_t * <var class="var">u</var>, const gnutls_datum_t * <var class="var">e1</var>, const gnutls_datum_t * <var class="var">e2</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fimport_005frsa_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: The structure to store the parsed key
</p>
<p><var class="var">m</var>: holds the modulus
</p>
<p><var class="var">e</var>: holds the public exponent
</p>
<p><var class="var">d</var>: holds the private exponent (optional)
</p>
<p><var class="var">p</var>: holds the first prime (p)
</p>
<p><var class="var">q</var>: holds the second prime (q)
</p>
<p><var class="var">u</var>: holds the coefficient (optional)
</p>
<p><var class="var">e1</var>: holds e1 = d mod (p-1) (optional)
</p>
<p><var class="var">e2</var>: holds e2 = d mod (q-1) (optional)
</p>
<p>This function will convert the given RSA raw parameters to the
native <code class="code">gnutls_privkey_t</code>  format.  The output will be stored in
 <code class="code">key</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fimport_005ftpm_005fraw-1"><span>gnutls_privkey_import_tpm_raw<a class="copiable-link" href="#gnutls_005fprivkey_005fimport_005ftpm_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fimport_005ftpm_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fimport_005ftpm_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_import_tpm_raw</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">pkey</var>, const gnutls_datum_t * <var class="var">fdata</var>, gnutls_tpmkey_fmt_t <var class="var">format</var>, const char * <var class="var">srk_password</var>, const char * <var class="var">key_password</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fimport_005ftpm_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">pkey</var>: The private key
</p>
<p><var class="var">fdata</var>: The TPM key to be imported
</p>
<p><var class="var">format</var>: The format of the private key
</p>
<p><var class="var">srk_password</var>: The password for the SRK key (optional)
</p>
<p><var class="var">key_password</var>: A password for the key (optional)
</p>
<p><var class="var">flags</var>: should be zero
</p>
<p>This function will import the given private key to the abstract
<code class="code">gnutls_privkey_t</code>  type. 
</p>
<p>With respect to passwords the same as in <code class="code">gnutls_privkey_import_tpm_url()</code>  apply.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.1.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fimport_005ftpm_005furl-1"><span>gnutls_privkey_import_tpm_url<a class="copiable-link" href="#gnutls_005fprivkey_005fimport_005ftpm_005furl-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fimport_005ftpm_005furl"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fimport_005ftpm_005furl-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_import_tpm_url</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">pkey</var>, const char * <var class="var">url</var>, const char * <var class="var">srk_password</var>, const char * <var class="var">key_password</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fimport_005ftpm_005furl-1"> &para;</a></span></dt>
<dd><p><var class="var">pkey</var>: The private key
</p>
<p><var class="var">url</var>: The URL of the TPM key to be imported
</p>
<p><var class="var">srk_password</var>: The password for the SRK key (optional)
</p>
<p><var class="var">key_password</var>: A password for the key (optional)
</p>
<p><var class="var">flags</var>: One of the GNUTLS_PRIVKEY_* flags
</p>
<p>This function will import the given private key to the abstract
<code class="code">gnutls_privkey_t</code>  type.
</p>
<p>Note that unless <code class="code">GNUTLS_PRIVKEY_DISABLE_CALLBACKS</code> 
is specified, if incorrect (or NULL) passwords are given
the PKCS11 callback functions will be used to obtain the
correct passwords. Otherwise if the SRK password is wrong
<code class="code">GNUTLS_E_TPM_SRK_PASSWORD_ERROR</code>  is returned and if the key password
is wrong or not provided then <code class="code">GNUTLS_E_TPM_KEY_PASSWORD_ERROR</code> 
is returned. 
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.1.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fimport_005furl-1"><span>gnutls_privkey_import_url<a class="copiable-link" href="#gnutls_005fprivkey_005fimport_005furl-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fimport_005furl"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fimport_005furl-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_import_url</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">key</var>, const char * <var class="var">url</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fimport_005furl-1"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: A key of type <code class="code">gnutls_privkey_t</code> 
</p>
<p><var class="var">url</var>: A PKCS 11 url
</p>
<p><var class="var">flags</var>: should be zero
</p>
<p>This function will import a PKCS11 or TPM URL as a
private key. The supported URL types can be checked
using <code class="code">gnutls_url_is_supported()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.1.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fimport_005fx509-1"><span>gnutls_privkey_import_x509<a class="copiable-link" href="#gnutls_005fprivkey_005fimport_005fx509-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fimport_005fx509"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fimport_005fx509"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_import_x509</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">pkey</var>, gnutls_x509_privkey_t <var class="var">key</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fimport_005fx509"> &para;</a></span></dt>
<dd><p><var class="var">pkey</var>: The private key
</p>
<p><var class="var">key</var>: The private key to be imported
</p>
<p><var class="var">flags</var>: Flags for the import
</p>
<p>This function will import the given private key to the abstract
<code class="code">gnutls_privkey_t</code>  type.
</p>
<p>The <code class="code">gnutls_x509_privkey_t</code>  object must not be deallocated
during the lifetime of this structure.
</p>
<p><code class="code">flags</code> might be zero or one of <code class="code">GNUTLS_PRIVKEY_IMPORT_AUTO_RELEASE</code> 
and <code class="code">GNUTLS_PRIVKEY_IMPORT_COPY</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fimport_005fx509_005fraw-1"><span>gnutls_privkey_import_x509_raw<a class="copiable-link" href="#gnutls_005fprivkey_005fimport_005fx509_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fimport_005fx509_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fimport_005fx509_005fraw-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_import_x509_raw</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">pkey</var>, const gnutls_datum_t * <var class="var">data</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, const char * <var class="var">password</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fimport_005fx509_005fraw-1"> &para;</a></span></dt>
<dd><p><var class="var">pkey</var>: The private key
</p>
<p><var class="var">data</var>: The private key data to be imported
</p>
<p><var class="var">format</var>: The format of the private key
</p>
<p><var class="var">password</var>: A password (optional)
</p>
<p><var class="var">flags</var>: an ORed sequence of gnutls_pkcs_encrypt_flags_t
</p>
<p>This function will import the given private key to the abstract
<code class="code">gnutls_privkey_t</code>  type. 
</p>
<p>The supported formats are basic unencrypted key, PKCS8, PKCS12, 
TSS2, and the openssl format.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.1.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005finit-1"><span>gnutls_privkey_init<a class="copiable-link" href="#gnutls_005fprivkey_005finit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005finit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005finit"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_init</strong> <code class="def-code-arguments">(gnutls_privkey_t * <var class="var">key</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005finit"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: A pointer to the type to be initialized
</p>
<p>This function will initialize a private key object. The object can
be used to generate, import, and perform cryptographic operations
on the associated private key.
</p>
<p>Note that when the underlying private key is a PKCS<code class="code">11</code>  key (i.e.,
when imported with a PKCS<code class="code">11</code>  URI), the limitations of <code class="code">gnutls_pkcs11_privkey_init()</code> 
apply to this object as well. In versions of GnuTLS later than 3.5.11 the object
is protected using locks and a single <code class="code">gnutls_privkey_t</code>  can be re-used
by many threads. However, for performance it is recommended to utilize
one object per key per thread.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fset_005fflags-1"><span>gnutls_privkey_set_flags<a class="copiable-link" href="#gnutls_005fprivkey_005fset_005fflags-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fset_005fflags"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fset_005fflags"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_privkey_set_flags</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">key</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fset_005fflags"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: A key of type <code class="code">gnutls_privkey_t</code> 
</p>
<p><var class="var">flags</var>: flags from the <code class="code">gnutls_privkey_flags</code> 
</p>
<p>This function will set flags for the specified private key, after
it is generated. Currently this is useful for the <code class="code">GNUTLS_PRIVKEY_FLAG_EXPORT_COMPAT</code> 
to allow exporting a &quot;provable&quot; private key in backwards compatible way.
</p>
<p><strong class="strong">Since:</strong> 3.5.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fset_005fpin_005ffunction-1"><span>gnutls_privkey_set_pin_function<a class="copiable-link" href="#gnutls_005fprivkey_005fset_005fpin_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fset_005fpin_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fset_005fpin_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_privkey_set_pin_function</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">key</var>, gnutls_pin_callback_t <var class="var">fn</var>, void * <var class="var">userdata</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fset_005fpin_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: A key of type <code class="code">gnutls_privkey_t</code> 
</p>
<p><var class="var">fn</var>: the callback
</p>
<p><var class="var">userdata</var>: data associated with the callback
</p>
<p>This function will set a callback function to be used when
required to access the object. This function overrides any other
global PIN functions.
</p>
<p>Note that this function must be called right after initialization
to have effect.
</p>
<p><strong class="strong">Since:</strong> 3.1.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fset_005fspki-1"><span>gnutls_privkey_set_spki<a class="copiable-link" href="#gnutls_005fprivkey_005fset_005fspki-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fset_005fspki"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fset_005fspki"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_set_spki</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">privkey</var>, const gnutls_x509_spki_t <var class="var">spki</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fset_005fspki"> &para;</a></span></dt>
<dd><p><var class="var">privkey</var>: a public key of type <code class="code">gnutls_privkey_t</code> 
</p>
<p><var class="var">spki</var>: a SubjectPublicKeyInfo structure of type <code class="code">gnutls_privkey_spki_t</code> 
</p>
<p><var class="var">flags</var>: must be zero
</p>
<p>This function will set the public key information.
The provided  <code class="code">spki</code> must be initialized.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fsign_005fdata-1"><span>gnutls_privkey_sign_data<a class="copiable-link" href="#gnutls_005fprivkey_005fsign_005fdata-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fsign_005fdata"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fsign_005fdata-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_sign_data</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">signer</var>, gnutls_digest_algorithm_t <var class="var">hash</var>, unsigned int <var class="var">flags</var>, const gnutls_datum_t * <var class="var">data</var>, gnutls_datum_t * <var class="var">signature</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fsign_005fdata-1"> &para;</a></span></dt>
<dd><p><var class="var">signer</var>: Holds the key
</p>
<p><var class="var">hash</var>: should be a digest algorithm
</p>
<p><var class="var">flags</var>: Zero or one of <code class="code">gnutls_privkey_flags_t</code> 
</p>
<p><var class="var">data</var>: holds the data to be signed
</p>
<p><var class="var">signature</var>: will contain the signature allocated with <code class="code">gnutls_malloc()</code> 
</p>
<p>This function will sign the given data using a signature algorithm
supported by the private key. Signature algorithms are always used
together with a hash functions.  Different hash functions may be
used for the RSA algorithm, but only the SHA family for the DSA keys.
</p>
<p>You may use <code class="code">gnutls_pubkey_get_preferred_hash_algorithm()</code>  to determine
the hash algorithm.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fsign_005fdata2-1"><span>gnutls_privkey_sign_data2<a class="copiable-link" href="#gnutls_005fprivkey_005fsign_005fdata2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fsign_005fdata2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fsign_005fdata2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_sign_data2</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">signer</var>, gnutls_sign_algorithm_t <var class="var">algo</var>, unsigned int <var class="var">flags</var>, const gnutls_datum_t * <var class="var">data</var>, gnutls_datum_t * <var class="var">signature</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fsign_005fdata2"> &para;</a></span></dt>
<dd><p><var class="var">signer</var>: Holds the key
</p>
<p><var class="var">algo</var>: The signature algorithm used
</p>
<p><var class="var">flags</var>: Zero or one of <code class="code">gnutls_privkey_flags_t</code> 
</p>
<p><var class="var">data</var>: holds the data to be signed
</p>
<p><var class="var">signature</var>: will contain the signature allocated with <code class="code">gnutls_malloc()</code> 
</p>
<p>This function will sign the given data using the specified signature
algorithm. This function is an enhancement of <code class="code">gnutls_privkey_sign_data()</code> ,
as it allows utilizing a alternative signature algorithm where possible
(e.g, use an RSA key with RSA-PSS).
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fsign_005fhash-1"><span>gnutls_privkey_sign_hash<a class="copiable-link" href="#gnutls_005fprivkey_005fsign_005fhash-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fsign_005fhash"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fsign_005fhash-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_sign_hash</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">signer</var>, gnutls_digest_algorithm_t <var class="var">hash_algo</var>, unsigned int <var class="var">flags</var>, const gnutls_datum_t * <var class="var">hash_data</var>, gnutls_datum_t * <var class="var">signature</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fsign_005fhash-1"> &para;</a></span></dt>
<dd><p><var class="var">signer</var>: Holds the signer&rsquo;s key
</p>
<p><var class="var">hash_algo</var>: The hash algorithm used
</p>
<p><var class="var">flags</var>: Zero or one of <code class="code">gnutls_privkey_flags_t</code> 
</p>
<p><var class="var">hash_data</var>: holds the data to be signed
</p>
<p><var class="var">signature</var>: will contain newly allocated signature
</p>
<p>This function will sign the given hashed data using a signature algorithm
supported by the private key. Signature algorithms are always used
together with a hash functions.  Different hash functions may be
used for the RSA algorithm, but only SHA-XXX for the DSA keys.
</p>
<p>You may use <code class="code">gnutls_pubkey_get_preferred_hash_algorithm()</code>  to determine
the hash algorithm.
</p>
<p>The flags may be <code class="code">GNUTLS_PRIVKEY_SIGN_FLAG_TLS1_RSA</code>  or <code class="code">GNUTLS_PRIVKEY_SIGN_FLAG_RSA_PSS</code> .
In the former case this function will ignore  <code class="code">hash_algo</code> and perform a raw PKCS1 signature,
and in the latter an RSA-PSS signature will be generated.
</p>
<p>Note that, not all algorithm support signing already hashed data. When
signing with Ed25519, <code class="code">gnutls_privkey_sign_data()</code>  should be used.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fsign_005fhash2-1"><span>gnutls_privkey_sign_hash2<a class="copiable-link" href="#gnutls_005fprivkey_005fsign_005fhash2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fsign_005fhash2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fsign_005fhash2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_sign_hash2</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">signer</var>, gnutls_sign_algorithm_t <var class="var">algo</var>, unsigned int <var class="var">flags</var>, const gnutls_datum_t * <var class="var">hash_data</var>, gnutls_datum_t * <var class="var">signature</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fsign_005fhash2"> &para;</a></span></dt>
<dd><p><var class="var">signer</var>: Holds the signer&rsquo;s key
</p>
<p><var class="var">algo</var>: The signature algorithm used
</p>
<p><var class="var">flags</var>: Zero or one of <code class="code">gnutls_privkey_flags_t</code> 
</p>
<p><var class="var">hash_data</var>: holds the data to be signed
</p>
<p><var class="var">signature</var>: will contain newly allocated signature
</p>
<p>This function will sign the given hashed data using the specified signature
algorithm. This function is an enhancement of <code class="code">gnutls_privkey_sign_hash()</code> ,
as it allows utilizing a alternative signature algorithm where possible
(e.g, use an RSA key with RSA-PSS).
</p>
<p>The flags may be <code class="code">GNUTLS_PRIVKEY_SIGN_FLAG_TLS1_RSA</code> .
In that case this function will ignore  <code class="code">hash_algo</code> and perform a raw PKCS1 signature.
Note that this flag is supported since 3.6.9.
</p>
<p>Note also that, not all algorithm support signing already hashed data. When
signing with Ed25519, <code class="code">gnutls_privkey_sign_data2()</code>  should be used instead.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fstatus-1"><span>gnutls_privkey_status<a class="copiable-link" href="#gnutls_005fprivkey_005fstatus-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fstatus"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fstatus"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_status</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">key</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fstatus"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: Holds the key
</p>
<p>Checks the status of the private key token. This function
is an actual wrapper over <code class="code">gnutls_pkcs11_privkey_status()</code> , and
if the private key is a PKCS <code class="code">11</code>  token it will check whether
it is inserted or not.
</p>
<p><strong class="strong">Returns:</strong> this function will return non-zero if the token 
holding the private key is still available (inserted), and zero otherwise.
</p>
<p><strong class="strong">Since:</strong> 3.1.10
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fverify_005fparams-1"><span>gnutls_privkey_verify_params<a class="copiable-link" href="#gnutls_005fprivkey_005fverify_005fparams-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fverify_005fparams"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fverify_005fparams"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_verify_params</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">key</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fverify_005fparams"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: should contain a <code class="code">gnutls_privkey_t</code>  type
</p>
<p>This function will verify the private key parameters.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fprivkey_005fverify_005fseed-1"><span>gnutls_privkey_verify_seed<a class="copiable-link" href="#gnutls_005fprivkey_005fverify_005fseed-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fprivkey_005fverify_005fseed"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fprivkey_005fverify_005fseed"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_privkey_verify_seed</strong> <code class="def-code-arguments">(gnutls_privkey_t <var class="var">key</var>, gnutls_digest_algorithm_t <var class="var">digest</var>, const void * <var class="var">seed</var>, size_t <var class="var">seed_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fprivkey_005fverify_005fseed"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: should contain a <code class="code">gnutls_privkey_t</code>  type
</p>
<p><var class="var">digest</var>: it contains the digest algorithm used for key generation (if applicable)
</p>
<p><var class="var">seed</var>: the seed of the key to be checked with
</p>
<p><var class="var">seed_size</var>: holds the size of  <code class="code">seed</code> 
</p>
<p>This function will verify that the given private key was generated from
the provided seed.
</p>
<p><strong class="strong">Returns:</strong> In case of a verification failure <code class="code">GNUTLS_E_PRIVKEY_VERIFICATION_ERROR</code> 
is returned, and zero or positive code on success.
</p>
<p><strong class="strong">Since:</strong> 3.5.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fdeinit-1"><span>gnutls_pubkey_deinit<a class="copiable-link" href="#gnutls_005fpubkey_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_pubkey_deinit</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">key</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: The key to be deinitialized
</p>
<p>This function will deinitialize a public key structure.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fencrypt_005fdata-1"><span>gnutls_pubkey_encrypt_data<a class="copiable-link" href="#gnutls_005fpubkey_005fencrypt_005fdata-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fencrypt_005fdata"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fencrypt_005fdata-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_encrypt_data</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">key</var>, unsigned int <var class="var">flags</var>, const gnutls_datum_t * <var class="var">plaintext</var>, gnutls_datum_t * <var class="var">ciphertext</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fencrypt_005fdata-1"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: Holds the public key
</p>
<p><var class="var">flags</var>: should be 0 for now
</p>
<p><var class="var">plaintext</var>: The data to be encrypted
</p>
<p><var class="var">ciphertext</var>: contains the encrypted data
</p>
<p>This function will encrypt the given data, using the public
key. On success the  <code class="code">ciphertext</code> will be allocated using <code class="code">gnutls_malloc()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fexport-1"><span>gnutls_pubkey_export<a class="copiable-link" href="#gnutls_005fpubkey_005fexport-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fexport"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fexport"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_export</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">key</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, void * <var class="var">output_data</var>, size_t * <var class="var">output_data_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fexport"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: Holds the certificate
</p>
<p><var class="var">format</var>: the format of output params. One of PEM or DER.
</p>
<p><var class="var">output_data</var>: will contain a certificate PEM or DER encoded
</p>
<p><var class="var">output_data_size</var>: holds the size of output_data (and will be
replaced by the actual size of parameters)
</p>
<p>This function will export the public key to DER or PEM format.
The contents of the exported data is the SubjectPublicKeyInfo
X.509 structure.
</p>
<p>If the buffer provided is not long enough to hold the output, then
*output_data_size is updated and <code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  will
be returned.
</p>
<p>If the structure is PEM encoded, it will have a header
of &quot;BEGIN CERTIFICATE&quot;.
</p>
<p><strong class="strong">Returns:</strong> In case of failure a negative error code will be
returned, and 0 on success.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fexport2-1"><span>gnutls_pubkey_export2<a class="copiable-link" href="#gnutls_005fpubkey_005fexport2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fexport2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fexport2-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_export2</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">key</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, gnutls_datum_t * <var class="var">out</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fexport2-1"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: Holds the certificate
</p>
<p><var class="var">format</var>: the format of output params. One of PEM or DER.
</p>
<p><var class="var">out</var>: will contain a certificate PEM or DER encoded
</p>
<p>This function will export the public key to DER or PEM format.
The contents of the exported data is the SubjectPublicKeyInfo
X.509 structure.
</p>
<p>The output buffer will be allocated using <code class="code">gnutls_malloc()</code> .
</p>
<p>If the structure is PEM encoded, it will have a header
of &quot;BEGIN CERTIFICATE&quot;.
</p>
<p><strong class="strong">Returns:</strong> In case of failure a negative error code will be
returned, and 0 on success.
</p>
<p><strong class="strong">Since:</strong> 3.1.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fexport_005fdh_005fraw-1"><span>gnutls_pubkey_export_dh_raw<a class="copiable-link" href="#gnutls_005fpubkey_005fexport_005fdh_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fexport_005fdh_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fexport_005fdh_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_export_dh_raw</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">key</var>, gnutls_dh_params_t <var class="var">params</var>, gnutls_datum_t * <var class="var">y</var>, unsigned <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fexport_005fdh_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: Holds the public key
</p>
<p><var class="var">params</var>: will hold the Diffie-Hellman parameter (optional), must be initialized
</p>
<p><var class="var">y</var>: will hold the y
</p>
<p><var class="var">flags</var>: flags from <code class="code">gnutls_abstract_export_flags_t</code> 
</p>
<p>This function will export the Diffie-Hellman public key parameter
found in the given public key.  The new parameter will be allocated
using <code class="code">gnutls_malloc()</code>  and will be stored in the appropriate datum.
</p>
<p>To retrieve other parameters common in both public key and private
key, use <code class="code">gnutls_dh_params_export_raw()</code> .
</p>
<p>This function allows for <code class="code">NULL</code>  parameters since 3.4.1.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.8.2
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fexport_005fdsa_005fraw-1"><span>gnutls_pubkey_export_dsa_raw<a class="copiable-link" href="#gnutls_005fpubkey_005fexport_005fdsa_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fexport_005fdsa_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fexport_005fdsa_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_export_dsa_raw</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">key</var>, gnutls_datum_t * <var class="var">p</var>, gnutls_datum_t * <var class="var">q</var>, gnutls_datum_t * <var class="var">g</var>, gnutls_datum_t * <var class="var">y</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fexport_005fdsa_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: Holds the public key
</p>
<p><var class="var">p</var>: will hold the p (may be <code class="code">NULL</code> )
</p>
<p><var class="var">q</var>: will hold the q (may be <code class="code">NULL</code> )
</p>
<p><var class="var">g</var>: will hold the g (may be <code class="code">NULL</code> )
</p>
<p><var class="var">y</var>: will hold the y (may be <code class="code">NULL</code> )
</p>
<p>This function will export the DSA public key&rsquo;s parameters found in
the given certificate.  The new parameters will be allocated using
<code class="code">gnutls_malloc()</code>  and will be stored in the appropriate datum.
</p>
<p>This function allows for <code class="code">NULL</code>  parameters since 3.4.1.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fexport_005fdsa_005fraw2-1"><span>gnutls_pubkey_export_dsa_raw2<a class="copiable-link" href="#gnutls_005fpubkey_005fexport_005fdsa_005fraw2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fexport_005fdsa_005fraw2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fexport_005fdsa_005fraw2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_export_dsa_raw2</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">key</var>, gnutls_datum_t * <var class="var">p</var>, gnutls_datum_t * <var class="var">q</var>, gnutls_datum_t * <var class="var">g</var>, gnutls_datum_t * <var class="var">y</var>, unsigned <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fexport_005fdsa_005fraw2"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: Holds the public key
</p>
<p><var class="var">p</var>: will hold the p (may be <code class="code">NULL</code> )
</p>
<p><var class="var">q</var>: will hold the q (may be <code class="code">NULL</code> )
</p>
<p><var class="var">g</var>: will hold the g (may be <code class="code">NULL</code> )
</p>
<p><var class="var">y</var>: will hold the y (may be <code class="code">NULL</code> )
</p>
<p><var class="var">flags</var>: flags from <code class="code">gnutls_abstract_export_flags_t</code> 
</p>
<p>This function will export the DSA public key&rsquo;s parameters found in
the given certificate.  The new parameters will be allocated using
<code class="code">gnutls_malloc()</code>  and will be stored in the appropriate datum.
</p>
<p>This function allows for <code class="code">NULL</code>  parameters since 3.4.1.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fexport_005fecc_005fraw-1"><span>gnutls_pubkey_export_ecc_raw<a class="copiable-link" href="#gnutls_005fpubkey_005fexport_005fecc_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fexport_005fecc_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fexport_005fecc_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_export_ecc_raw</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">key</var>, gnutls_ecc_curve_t * <var class="var">curve</var>, gnutls_datum_t * <var class="var">x</var>, gnutls_datum_t * <var class="var">y</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fexport_005fecc_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: Holds the public key
</p>
<p><var class="var">curve</var>: will hold the curve (may be <code class="code">NULL</code> )
</p>
<p><var class="var">x</var>: will hold x-coordinate (may be <code class="code">NULL</code> )
</p>
<p><var class="var">y</var>: will hold y-coordinate (may be <code class="code">NULL</code> )
</p>
<p>This function will export the ECC public key&rsquo;s parameters found in
the given key.  The new parameters will be allocated using
<code class="code">gnutls_malloc()</code>  and will be stored in the appropriate datum.
</p>
<p>In EdDSA curves the  <code class="code">y</code> parameter will be <code class="code">NULL</code>  and the other parameters
will be in the native format for the curve.
</p>
<p>This function allows for <code class="code">NULL</code>  parameters since 3.4.1.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fexport_005fecc_005fraw2-1"><span>gnutls_pubkey_export_ecc_raw2<a class="copiable-link" href="#gnutls_005fpubkey_005fexport_005fecc_005fraw2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fexport_005fecc_005fraw2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fexport_005fecc_005fraw2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_export_ecc_raw2</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">key</var>, gnutls_ecc_curve_t * <var class="var">curve</var>, gnutls_datum_t * <var class="var">x</var>, gnutls_datum_t * <var class="var">y</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fexport_005fecc_005fraw2"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: Holds the public key
</p>
<p><var class="var">curve</var>: will hold the curve (may be <code class="code">NULL</code> )
</p>
<p><var class="var">x</var>: will hold x-coordinate (may be <code class="code">NULL</code> )
</p>
<p><var class="var">y</var>: will hold y-coordinate (may be <code class="code">NULL</code> )
</p>
<p><var class="var">flags</var>: flags from <code class="code">gnutls_abstract_export_flags_t</code> 
</p>
<p>This function will export the ECC public key&rsquo;s parameters found in
the given key.  The new parameters will be allocated using
<code class="code">gnutls_malloc()</code>  and will be stored in the appropriate datum.
</p>
<p>In EdDSA curves the  <code class="code">y</code> parameter will be <code class="code">NULL</code>  and the other parameters
will be in the native format for the curve.
</p>
<p>This function allows for <code class="code">NULL</code>  parameters since 3.4.1.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fexport_005fecc_005fx962-1"><span>gnutls_pubkey_export_ecc_x962<a class="copiable-link" href="#gnutls_005fpubkey_005fexport_005fecc_005fx962-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fexport_005fecc_005fx962"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fexport_005fecc_005fx962"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_export_ecc_x962</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">key</var>, gnutls_datum_t * <var class="var">parameters</var>, gnutls_datum_t * <var class="var">ecpoint</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fexport_005fecc_005fx962"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: Holds the public key
</p>
<p><var class="var">parameters</var>: DER encoding of an ANSI X9.62 parameters
</p>
<p><var class="var">ecpoint</var>: DER encoding of ANSI X9.62 ECPoint
</p>
<p>This function will export the ECC public key&rsquo;s parameters found in
the given certificate.  The new parameters will be allocated using
<code class="code">gnutls_malloc()</code>  and will be stored in the appropriate datum.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fexport_005fgost_005fraw2-1"><span>gnutls_pubkey_export_gost_raw2<a class="copiable-link" href="#gnutls_005fpubkey_005fexport_005fgost_005fraw2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fexport_005fgost_005fraw2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fexport_005fgost_005fraw2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_export_gost_raw2</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">key</var>, gnutls_ecc_curve_t * <var class="var">curve</var>, gnutls_digest_algorithm_t * <var class="var">digest</var>, gnutls_gost_paramset_t * <var class="var">paramset</var>, gnutls_datum_t * <var class="var">x</var>, gnutls_datum_t * <var class="var">y</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fexport_005fgost_005fraw2"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: Holds the public key
</p>
<p><var class="var">curve</var>: will hold the curve (may be <code class="code">NULL</code> )
</p>
<p><var class="var">digest</var>: will hold the curve (may be <code class="code">NULL</code> )
</p>
<p><var class="var">paramset</var>: will hold the parameters id (may be <code class="code">NULL</code> )
</p>
<p><var class="var">x</var>: will hold the x-coordinate (may be <code class="code">NULL</code> )
</p>
<p><var class="var">y</var>: will hold the y-coordinate (may be <code class="code">NULL</code> )
</p>
<p><var class="var">flags</var>: flags from <code class="code">gnutls_abstract_export_flags_t</code> 
</p>
<p>This function will export the GOST public key&rsquo;s parameters found in
the given key.  The new parameters will be allocated using
<code class="code">gnutls_malloc()</code>  and will be stored in the appropriate datum.
</p>
<p><strong class="strong">Note:</strong> parameters will be stored with least significant byte first. On
version 3.6.3 this was incorrectly returned in big-endian format.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.6.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fexport_005frsa_005fraw-1"><span>gnutls_pubkey_export_rsa_raw<a class="copiable-link" href="#gnutls_005fpubkey_005fexport_005frsa_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fexport_005frsa_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fexport_005frsa_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_export_rsa_raw</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">key</var>, gnutls_datum_t * <var class="var">m</var>, gnutls_datum_t * <var class="var">e</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fexport_005frsa_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: Holds the certificate
</p>
<p><var class="var">m</var>: will hold the modulus (may be <code class="code">NULL</code> )
</p>
<p><var class="var">e</var>: will hold the public exponent (may be <code class="code">NULL</code> )
</p>
<p>This function will export the RSA public key&rsquo;s parameters found in
the given structure.  The new parameters will be allocated using
<code class="code">gnutls_malloc()</code>  and will be stored in the appropriate datum.
</p>
<p>This function allows for <code class="code">NULL</code>  parameters since 3.4.1.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fexport_005frsa_005fraw2-1"><span>gnutls_pubkey_export_rsa_raw2<a class="copiable-link" href="#gnutls_005fpubkey_005fexport_005frsa_005fraw2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fexport_005frsa_005fraw2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fexport_005frsa_005fraw2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_export_rsa_raw2</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">key</var>, gnutls_datum_t * <var class="var">m</var>, gnutls_datum_t * <var class="var">e</var>, unsigned <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fexport_005frsa_005fraw2"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: Holds the certificate
</p>
<p><var class="var">m</var>: will hold the modulus (may be <code class="code">NULL</code> )
</p>
<p><var class="var">e</var>: will hold the public exponent (may be <code class="code">NULL</code> )
</p>
<p><var class="var">flags</var>: flags from <code class="code">gnutls_abstract_export_flags_t</code> 
</p>
<p>This function will export the RSA public key&rsquo;s parameters found in
the given structure.  The new parameters will be allocated using
<code class="code">gnutls_malloc()</code>  and will be stored in the appropriate datum.
</p>
<p>This function allows for <code class="code">NULL</code>  parameters since 3.4.1.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fget_005fkey_005fid-1"><span>gnutls_pubkey_get_key_id<a class="copiable-link" href="#gnutls_005fpubkey_005fget_005fkey_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fget_005fkey_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fget_005fkey_005fid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_get_key_id</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">key</var>, unsigned int <var class="var">flags</var>, unsigned char * <var class="var">output_data</var>, size_t * <var class="var">output_data_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fget_005fkey_005fid"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: Holds the public key
</p>
<p><var class="var">flags</var>: should be one of the flags from <code class="code">gnutls_keyid_flags_t</code> 
</p>
<p><var class="var">output_data</var>: will contain the key ID
</p>
<p><var class="var">output_data_size</var>: holds the size of output_data (and will be
replaced by the actual size of parameters)
</p>
<p>This function will return a unique ID that depends on the public
key parameters. This ID can be used in checking whether a
certificate corresponds to the given public key.
</p>
<p>If the buffer provided is not long enough to hold the output, then
*output_data_size is updated and <code class="code">GNUTLS_E_SHORT_MEMORY_BUFFER</code>  will
be returned.  The output will normally be a SHA-1 hash output,
which is 20 bytes.
</p>
<p><strong class="strong">Returns:</strong> In case of failure a negative error code will be
returned, and 0 on success.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fget_005fkey_005fusage-1"><span>gnutls_pubkey_get_key_usage<a class="copiable-link" href="#gnutls_005fpubkey_005fget_005fkey_005fusage-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fget_005fkey_005fusage"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fget_005fkey_005fusage"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_get_key_usage</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">key</var>, unsigned int * <var class="var">usage</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fget_005fkey_005fusage"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: should contain a <code class="code">gnutls_pubkey_t</code>  type
</p>
<p><var class="var">usage</var>: If set will return the number of bits of the parameters (may be NULL)
</p>
<p>This function will return the key usage of the public key.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fget_005fopenpgp_005fkey_005fid-1"><span>gnutls_pubkey_get_openpgp_key_id<a class="copiable-link" href="#gnutls_005fpubkey_005fget_005fopenpgp_005fkey_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fget_005fopenpgp_005fkey_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fget_005fopenpgp_005fkey_005fid"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_get_openpgp_key_id</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">key</var>, unsigned int <var class="var">flags</var>, unsigned char * <var class="var">output_data</var>, size_t * <var class="var">output_data_size</var>, unsigned int * <var class="var">subkey</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fget_005fopenpgp_005fkey_005fid"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: Holds the public key
</p>
<p><var class="var">flags</var>: should be one of the flags from <code class="code">gnutls_keyid_flags_t</code> 
</p>
<p><var class="var">output_data</var>: will contain the key ID
</p>
<p><var class="var">output_data_size</var>: holds the size of output_data (and will be
replaced by the actual size of parameters)
</p>
<p><var class="var">subkey</var>: ignored
</p>
<p>This function is no-op.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_UNIMPLEMENTED_FEATURE</code> .
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fget_005fpk_005falgorithm-1"><span>gnutls_pubkey_get_pk_algorithm<a class="copiable-link" href="#gnutls_005fpubkey_005fget_005fpk_005falgorithm-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fget_005fpk_005falgorithm"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fget_005fpk_005falgorithm"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_get_pk_algorithm</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">key</var>, unsigned int * <var class="var">bits</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fget_005fpk_005falgorithm"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: should contain a <code class="code">gnutls_pubkey_t</code>  type
</p>
<p><var class="var">bits</var>: If set will return the number of bits of the parameters (may be NULL)
</p>
<p>This function will return the public key algorithm of a public
key and if possible will return a number of bits that indicates
the security parameter of the key.
</p>
<p><strong class="strong">Returns:</strong> a member of the <code class="code">gnutls_pk_algorithm_t</code>  enumeration on
success, or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fget_005fpreferred_005fhash_005falgorithm-1"><span>gnutls_pubkey_get_preferred_hash_algorithm<a class="copiable-link" href="#gnutls_005fpubkey_005fget_005fpreferred_005fhash_005falgorithm-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fget_005fpreferred_005fhash_005falgorithm"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fget_005fpreferred_005fhash_005falgorithm"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_get_preferred_hash_algorithm</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">key</var>, gnutls_digest_algorithm_t * <var class="var">hash</var>, unsigned int * <var class="var">mand</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fget_005fpreferred_005fhash_005falgorithm"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: Holds the certificate
</p>
<p><var class="var">hash</var>: The result of the call with the hash algorithm used for signature
</p>
<p><var class="var">mand</var>: If non zero it means that the algorithm MUST use this hash. May be NULL.
</p>
<p>This function will read the certificate and return the appropriate digest
algorithm to use for signing with this certificate. Some certificates (i.e.
DSA might not be able to sign without the preferred algorithm).
</p>
<p>To get the signature algorithm instead of just the hash use <code class="code">gnutls_pk_to_sign()</code> 
with the algorithm of the certificate/key and the provided  <code class="code">hash</code> .
</p>
<p><strong class="strong">Returns:</strong> the 0 if the hash algorithm is found. A negative error code is
returned on error.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fget_005fspki-1"><span>gnutls_pubkey_get_spki<a class="copiable-link" href="#gnutls_005fpubkey_005fget_005fspki-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fget_005fspki"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fget_005fspki"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_get_spki</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">pubkey</var>, gnutls_x509_spki_t <var class="var">spki</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fget_005fspki"> &para;</a></span></dt>
<dd><p><var class="var">pubkey</var>: a public key of type <code class="code">gnutls_pubkey_t</code> 
</p>
<p><var class="var">spki</var>: a SubjectPublicKeyInfo structure of type <code class="code">gnutls_pubkey_spki_t</code> 
</p>
<p><var class="var">flags</var>: must be zero
</p>
<p>This function will return the public key information if available.
The provided  <code class="code">spki</code> must be initialized.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fimport-1"><span>gnutls_pubkey_import<a class="copiable-link" href="#gnutls_005fpubkey_005fimport-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fimport"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fimport"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_import</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">key</var>, const gnutls_datum_t * <var class="var">data</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fimport"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: The public key. 
</p>
<p><var class="var">data</var>: The DER or PEM encoded certificate. 
</p>
<p><var class="var">format</var>: One of DER or PEM 
</p>
<p>This function will import the provided public key in
a SubjectPublicKeyInfo X.509 structure to a native
<code class="code">gnutls_pubkey_t</code>  type. The output will be stored 
in  <code class="code">key</code> . If the public key is PEM encoded it should have a header 
of &quot;PUBLIC KEY&quot;. 
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fimport_005fdh_005fraw-1"><span>gnutls_pubkey_import_dh_raw<a class="copiable-link" href="#gnutls_005fpubkey_005fimport_005fdh_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fimport_005fdh_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fimport_005fdh_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_import_dh_raw</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">key</var>, const gnutls_dh_params_t <var class="var">params</var>, const gnutls_datum_t * <var class="var">y</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fimport_005fdh_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: The structure to store the parsed key
</p>
<p><var class="var">params</var>: holds the <code class="code">gnutls_dh_params_t</code> 
</p>
<p><var class="var">y</var>: holds the y
</p>
<p>This function will convert the given Diffie-Hellman raw parameters
to the native <code class="code">gnutls_pubkey_t</code>  format.  The output will be stored
in  <code class="code">key</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.8.2
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fimport_005fdsa_005fraw-1"><span>gnutls_pubkey_import_dsa_raw<a class="copiable-link" href="#gnutls_005fpubkey_005fimport_005fdsa_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fimport_005fdsa_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fimport_005fdsa_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_import_dsa_raw</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">key</var>, const gnutls_datum_t * <var class="var">p</var>, const gnutls_datum_t * <var class="var">q</var>, const gnutls_datum_t * <var class="var">g</var>, const gnutls_datum_t * <var class="var">y</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fimport_005fdsa_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: The structure to store the parsed key
</p>
<p><var class="var">p</var>: holds the p
</p>
<p><var class="var">q</var>: holds the q
</p>
<p><var class="var">g</var>: holds the g
</p>
<p><var class="var">y</var>: holds the y
</p>
<p>This function will convert the given DSA raw parameters to the
native <code class="code">gnutls_pubkey_t</code>  format.  The output will be stored
in  <code class="code">key</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fimport_005fecc_005fraw-1"><span>gnutls_pubkey_import_ecc_raw<a class="copiable-link" href="#gnutls_005fpubkey_005fimport_005fecc_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fimport_005fecc_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fimport_005fecc_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_import_ecc_raw</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">key</var>, gnutls_ecc_curve_t <var class="var">curve</var>, const gnutls_datum_t * <var class="var">x</var>, const gnutls_datum_t * <var class="var">y</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fimport_005fecc_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: The structure to store the parsed key
</p>
<p><var class="var">curve</var>: holds the curve
</p>
<p><var class="var">x</var>: holds the x-coordinate
</p>
<p><var class="var">y</var>: holds the y-coordinate
</p>
<p>This function will convert the given elliptic curve parameters to a
<code class="code">gnutls_pubkey_t</code> .  The output will be stored in  <code class="code">key</code> .
</p>
<p>In EdDSA curves the  <code class="code">y</code> parameter should be <code class="code">NULL</code>  and the  <code class="code">x</code> parameter must
be the value in the native format for the curve.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fimport_005fecc_005fx962-1"><span>gnutls_pubkey_import_ecc_x962<a class="copiable-link" href="#gnutls_005fpubkey_005fimport_005fecc_005fx962-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fimport_005fecc_005fx962"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fimport_005fecc_005fx962"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_import_ecc_x962</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">key</var>, const gnutls_datum_t * <var class="var">parameters</var>, const gnutls_datum_t * <var class="var">ecpoint</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fimport_005fecc_005fx962"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: The structure to store the parsed key
</p>
<p><var class="var">parameters</var>: DER encoding of an ANSI X9.62 parameters
</p>
<p><var class="var">ecpoint</var>: DER encoding of ANSI X9.62 ECPoint
</p>
<p>This function will convert the given elliptic curve parameters to a
<code class="code">gnutls_pubkey_t</code> .  The output will be stored in  <code class="code">key</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fimport_005fgost_005fraw-1"><span>gnutls_pubkey_import_gost_raw<a class="copiable-link" href="#gnutls_005fpubkey_005fimport_005fgost_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fimport_005fgost_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fimport_005fgost_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_import_gost_raw</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">key</var>, gnutls_ecc_curve_t <var class="var">curve</var>, gnutls_digest_algorithm_t <var class="var">digest</var>, gnutls_gost_paramset_t <var class="var">paramset</var>, const gnutls_datum_t * <var class="var">x</var>, const gnutls_datum_t * <var class="var">y</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fimport_005fgost_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: The structure to store the parsed key
</p>
<p><var class="var">curve</var>: holds the curve
</p>
<p><var class="var">digest</var>: holds the digest
</p>
<p><var class="var">paramset</var>: holds the parameters id
</p>
<p><var class="var">x</var>: holds the x-coordinate
</p>
<p><var class="var">y</var>: holds the y-coordinate
</p>
<p>This function will convert the given GOST public key&rsquo;s parameters to a
<code class="code">gnutls_pubkey_t</code> .  The output will be stored in  <code class="code">key</code> .   <code class="code">digest</code> should be
one of GNUTLS_DIG_GOSR_94, GNUTLS_DIG_STREEBOG_256 or
GNUTLS_DIG_STREEBOG_512.  If  <code class="code">paramset</code> is set to GNUTLS_GOST_PARAMSET_UNKNOWN
default one will be selected depending on  <code class="code">digest</code> .
</p>
<p><strong class="strong">Note:</strong> parameters should be stored with least significant byte first. On
version 3.6.3 big-endian format was used incorrectly.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.6.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fimport_005fopenpgp-1"><span>gnutls_pubkey_import_openpgp<a class="copiable-link" href="#gnutls_005fpubkey_005fimport_005fopenpgp-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fimport_005fopenpgp"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fimport_005fopenpgp"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_import_openpgp</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">key</var>, gnutls_openpgp_crt_t <var class="var">crt</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fimport_005fopenpgp"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: The public key
</p>
<p><var class="var">crt</var>: The certificate to be imported
</p>
<p><var class="var">flags</var>: should be zero
</p>
<p>This function is no-op.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_UNIMPLEMENTED_FEATURE</code> .
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fimport_005fopenpgp_005fraw-1"><span>gnutls_pubkey_import_openpgp_raw<a class="copiable-link" href="#gnutls_005fpubkey_005fimport_005fopenpgp_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fimport_005fopenpgp_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fimport_005fopenpgp_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_import_openpgp_raw</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">pkey</var>, const gnutls_datum_t * <var class="var">data</var>, gnutls_openpgp_crt_fmt_t <var class="var">format</var>, const gnutls_openpgp_keyid_t <var class="var">keyid</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fimport_005fopenpgp_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">pkey</var>: The public key
</p>
<p><var class="var">data</var>: The public key data to be imported
</p>
<p><var class="var">format</var>: The format of the public key
</p>
<p><var class="var">keyid</var>: The key id to use (optional)
</p>
<p><var class="var">flags</var>: Should be zero
</p>
<p>This function is no-op.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_UNIMPLEMENTED_FEATURE</code> .
</p>
<p><strong class="strong">Since:</strong> 3.1.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fimport_005fpkcs11-1"><span>gnutls_pubkey_import_pkcs11<a class="copiable-link" href="#gnutls_005fpubkey_005fimport_005fpkcs11-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fimport_005fpkcs11"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fimport_005fpkcs11"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_import_pkcs11</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">key</var>, gnutls_pkcs11_obj_t <var class="var">obj</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fimport_005fpkcs11"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: The public key
</p>
<p><var class="var">obj</var>: The parameters to be imported
</p>
<p><var class="var">flags</var>: should be zero
</p>
<p>Imports a public key from a pkcs11 key. This function will import
the given public key to the abstract <code class="code">gnutls_pubkey_t</code>  type.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fimport_005fprivkey-1"><span>gnutls_pubkey_import_privkey<a class="copiable-link" href="#gnutls_005fpubkey_005fimport_005fprivkey-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fimport_005fprivkey"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fimport_005fprivkey"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_import_privkey</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">key</var>, gnutls_privkey_t <var class="var">pkey</var>, unsigned int <var class="var">usage</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fimport_005fprivkey"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: The public key
</p>
<p><var class="var">pkey</var>: The private key
</p>
<p><var class="var">usage</var>: GNUTLS_KEY_* key usage flags.
</p>
<p><var class="var">flags</var>: should be zero
</p>
<p>Imports the public key from a private.  This function will import
the given public key to the abstract <code class="code">gnutls_pubkey_t</code>  type.
</p>
<p>Note that in certain keys this operation may not be possible, e.g.,
in other than RSA PKCS<code class="code">11</code>  keys.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fimport_005frsa_005fraw-1"><span>gnutls_pubkey_import_rsa_raw<a class="copiable-link" href="#gnutls_005fpubkey_005fimport_005frsa_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fimport_005frsa_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fimport_005frsa_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_import_rsa_raw</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">key</var>, const gnutls_datum_t * <var class="var">m</var>, const gnutls_datum_t * <var class="var">e</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fimport_005frsa_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: The key
</p>
<p><var class="var">m</var>: holds the modulus
</p>
<p><var class="var">e</var>: holds the public exponent
</p>
<p>This function will replace the parameters in the given structure.
The new parameters should be stored in the appropriate
gnutls_datum.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, or an negative error code.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fimport_005ftpm_005fraw-1"><span>gnutls_pubkey_import_tpm_raw<a class="copiable-link" href="#gnutls_005fpubkey_005fimport_005ftpm_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fimport_005ftpm_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fimport_005ftpm_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_import_tpm_raw</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">pkey</var>, const gnutls_datum_t * <var class="var">fdata</var>, gnutls_tpmkey_fmt_t <var class="var">format</var>, const char * <var class="var">srk_password</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fimport_005ftpm_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">pkey</var>: The public key
</p>
<p><var class="var">fdata</var>: The TPM key to be imported
</p>
<p><var class="var">format</var>: The format of the private key
</p>
<p><var class="var">srk_password</var>: The password for the SRK key (optional)
</p>
<p><var class="var">flags</var>: One of the GNUTLS_PUBKEY_* flags
</p>
<p>This function will import the public key from the provided TPM key
structure.
</p>
<p>With respect to passwords the same as in
<code class="code">gnutls_pubkey_import_tpm_url()</code>  apply.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.1.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fimport_005ftpm_005furl-1"><span>gnutls_pubkey_import_tpm_url<a class="copiable-link" href="#gnutls_005fpubkey_005fimport_005ftpm_005furl-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fimport_005ftpm_005furl"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fimport_005ftpm_005furl-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_import_tpm_url</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">pkey</var>, const char * <var class="var">url</var>, const char * <var class="var">srk_password</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fimport_005ftpm_005furl-1"> &para;</a></span></dt>
<dd><p><var class="var">pkey</var>: The public key
</p>
<p><var class="var">url</var>: The URL of the TPM key to be imported
</p>
<p><var class="var">srk_password</var>: The password for the SRK key (optional)
</p>
<p><var class="var">flags</var>: should be zero
</p>
<p>This function will import the given private key to the abstract
<code class="code">gnutls_privkey_t</code>  type. 
</p>
<p>Note that unless <code class="code">GNUTLS_PUBKEY_DISABLE_CALLBACKS</code> 
is specified, if incorrect (or NULL) passwords are given
the PKCS11 callback functions will be used to obtain the
correct passwords. Otherwise if the SRK password is wrong
<code class="code">GNUTLS_E_TPM_SRK_PASSWORD_ERROR</code>  is returned.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.1.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fimport_005furl-1"><span>gnutls_pubkey_import_url<a class="copiable-link" href="#gnutls_005fpubkey_005fimport_005furl-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fimport_005furl"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fimport_005furl"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_import_url</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">key</var>, const char * <var class="var">url</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fimport_005furl"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: A key of type <code class="code">gnutls_pubkey_t</code> 
</p>
<p><var class="var">url</var>: A PKCS 11 url
</p>
<p><var class="var">flags</var>: One of GNUTLS_PKCS11_OBJ_* flags
</p>
<p>This function will import a public key from the provided URL.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.1.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fimport_005fx509-1"><span>gnutls_pubkey_import_x509<a class="copiable-link" href="#gnutls_005fpubkey_005fimport_005fx509-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fimport_005fx509"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fimport_005fx509"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_import_x509</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">key</var>, gnutls_x509_crt_t <var class="var">crt</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fimport_005fx509"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: The public key
</p>
<p><var class="var">crt</var>: The certificate to be imported
</p>
<p><var class="var">flags</var>: should be zero
</p>
<p>This function will import the given public key to the abstract
<code class="code">gnutls_pubkey_t</code>  type.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fimport_005fx509_005fcrq-1"><span>gnutls_pubkey_import_x509_crq<a class="copiable-link" href="#gnutls_005fpubkey_005fimport_005fx509_005fcrq-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fimport_005fx509_005fcrq"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fimport_005fx509_005fcrq"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_import_x509_crq</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">key</var>, gnutls_x509_crq_t <var class="var">crq</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fimport_005fx509_005fcrq"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: The public key
</p>
<p><var class="var">crq</var>: The certificate to be imported
</p>
<p><var class="var">flags</var>: should be zero
</p>
<p>This function will import the given public key to the abstract
<code class="code">gnutls_pubkey_t</code>  type.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.1.5
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fimport_005fx509_005fraw-1"><span>gnutls_pubkey_import_x509_raw<a class="copiable-link" href="#gnutls_005fpubkey_005fimport_005fx509_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fimport_005fx509_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fimport_005fx509_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_import_x509_raw</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">pkey</var>, const gnutls_datum_t * <var class="var">data</var>, gnutls_x509_crt_fmt_t <var class="var">format</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fimport_005fx509_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">pkey</var>: The public key
</p>
<p><var class="var">data</var>: The public key data to be imported
</p>
<p><var class="var">format</var>: The format of the public key
</p>
<p><var class="var">flags</var>: should be zero
</p>
<p>This function will import the given public key to the abstract
<code class="code">gnutls_pubkey_t</code>  type. 
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.1.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005finit-1"><span>gnutls_pubkey_init<a class="copiable-link" href="#gnutls_005fpubkey_005finit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005finit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005finit"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_init</strong> <code class="def-code-arguments">(gnutls_pubkey_t * <var class="var">key</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005finit"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: A pointer to the type to be initialized
</p>
<p>This function will initialize a public key.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fprint-1"><span>gnutls_pubkey_print<a class="copiable-link" href="#gnutls_005fpubkey_005fprint-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fprint"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fprint"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_print</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">pubkey</var>, gnutls_certificate_print_formats_t <var class="var">format</var>, gnutls_datum_t * <var class="var">out</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fprint"> &para;</a></span></dt>
<dd><p><var class="var">pubkey</var>: The data to be printed
</p>
<p><var class="var">format</var>: Indicate the format to use
</p>
<p><var class="var">out</var>: Newly allocated datum with null terminated string.
</p>
<p>This function will pretty print public key information, suitable for
display to a human.
</p>
<p>Only <code class="code">GNUTLS_CRT_PRINT_FULL</code>  and <code class="code">GNUTLS_CRT_PRINT_FULL_NUMBERS</code> 
are implemented.
</p>
<p>The output  <code class="code">out</code> needs to be deallocated using <code class="code">gnutls_free()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.1.5
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fset_005fkey_005fusage-1"><span>gnutls_pubkey_set_key_usage<a class="copiable-link" href="#gnutls_005fpubkey_005fset_005fkey_005fusage-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fset_005fkey_005fusage"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fset_005fkey_005fusage"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_set_key_usage</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">key</var>, unsigned int <var class="var">usage</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fset_005fkey_005fusage"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: a certificate of type <code class="code">gnutls_x509_crt_t</code> 
</p>
<p><var class="var">usage</var>: an ORed sequence of the GNUTLS_KEY_* elements.
</p>
<p>This function will set the key usage flags of the public key. This
is only useful if the key is to be exported to a certificate or
certificate request.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fset_005fpin_005ffunction-1"><span>gnutls_pubkey_set_pin_function<a class="copiable-link" href="#gnutls_005fpubkey_005fset_005fpin_005ffunction-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fset_005fpin_005ffunction"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fset_005fpin_005ffunction"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_pubkey_set_pin_function</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">key</var>, gnutls_pin_callback_t <var class="var">fn</var>, void * <var class="var">userdata</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fset_005fpin_005ffunction"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: A key of type <code class="code">gnutls_pubkey_t</code> 
</p>
<p><var class="var">fn</var>: the callback
</p>
<p><var class="var">userdata</var>: data associated with the callback
</p>
<p>This function will set a callback function to be used when
required to access the object. This function overrides any other
global PIN functions.
</p>
<p>Note that this function must be called right after initialization
to have effect.
</p>
<p><strong class="strong">Since:</strong> 3.1.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fset_005fspki-1"><span>gnutls_pubkey_set_spki<a class="copiable-link" href="#gnutls_005fpubkey_005fset_005fspki-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fset_005fspki"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fset_005fspki"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_set_spki</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">pubkey</var>, const gnutls_x509_spki_t <var class="var">spki</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fset_005fspki"> &para;</a></span></dt>
<dd><p><var class="var">pubkey</var>: a public key of type <code class="code">gnutls_pubkey_t</code> 
</p>
<p><var class="var">spki</var>: a SubjectPublicKeyInfo structure of type <code class="code">gnutls_pubkey_spki_t</code> 
</p>
<p><var class="var">flags</var>: must be zero
</p>
<p>This function will set the public key information.
The provided  <code class="code">spki</code> must be initialized.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fverify_005fdata2-1"><span>gnutls_pubkey_verify_data2<a class="copiable-link" href="#gnutls_005fpubkey_005fverify_005fdata2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fverify_005fdata2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fverify_005fdata2-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_verify_data2</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">pubkey</var>, gnutls_sign_algorithm_t <var class="var">algo</var>, unsigned int <var class="var">flags</var>, const gnutls_datum_t * <var class="var">data</var>, const gnutls_datum_t * <var class="var">signature</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fverify_005fdata2-1"> &para;</a></span></dt>
<dd><p><var class="var">pubkey</var>: Holds the public key
</p>
<p><var class="var">algo</var>: The signature algorithm used
</p>
<p><var class="var">flags</var>: Zero or an OR list of <code class="code">gnutls_certificate_verify_flags</code> 
</p>
<p><var class="var">data</var>: holds the signed data
</p>
<p><var class="var">signature</var>: contains the signature
</p>
<p>This function will verify the given signed data, using the
parameters from the certificate.
</p>
<p><strong class="strong">Returns:</strong> In case of a verification failure <code class="code">GNUTLS_E_PK_SIG_VERIFY_FAILED</code>  
is returned, and zero or positive code on success. For known to be insecure
signatures this function will return <code class="code">GNUTLS_E_INSUFFICIENT_SECURITY</code>  unless
the flag <code class="code">GNUTLS_VERIFY_ALLOW_BROKEN</code>  is specified.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fverify_005fhash2-1"><span>gnutls_pubkey_verify_hash2<a class="copiable-link" href="#gnutls_005fpubkey_005fverify_005fhash2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fverify_005fhash2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fverify_005fhash2-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_verify_hash2</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">key</var>, gnutls_sign_algorithm_t <var class="var">algo</var>, unsigned int <var class="var">flags</var>, const gnutls_datum_t * <var class="var">hash</var>, const gnutls_datum_t * <var class="var">signature</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fverify_005fhash2-1"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: Holds the public key
</p>
<p><var class="var">algo</var>: The signature algorithm used
</p>
<p><var class="var">flags</var>: Zero or an OR list of <code class="code">gnutls_certificate_verify_flags</code> 
</p>
<p><var class="var">hash</var>: holds the hash digest to be verified
</p>
<p><var class="var">signature</var>: contains the signature
</p>
<p>This function will verify the given signed digest, using the
parameters from the public key. Note that unlike <code class="code">gnutls_privkey_sign_hash()</code> ,
this function accepts a signature algorithm instead of a digest algorithm.
You can use <code class="code">gnutls_pk_to_sign()</code>  to get the appropriate value.
</p>
<p><strong class="strong">Returns:</strong> In case of a verification failure <code class="code">GNUTLS_E_PK_SIG_VERIFY_FAILED</code>  
is returned, and zero or positive code on success. For known to be insecure
signatures this function will return <code class="code">GNUTLS_E_INSUFFICIENT_SECURITY</code>  unless
the flag <code class="code">GNUTLS_VERIFY_ALLOW_BROKEN</code>  is specified.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpubkey_005fverify_005fparams-1"><span>gnutls_pubkey_verify_params<a class="copiable-link" href="#gnutls_005fpubkey_005fverify_005fparams-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpubkey_005fverify_005fparams"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpubkey_005fverify_005fparams"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pubkey_verify_params</strong> <code class="def-code-arguments">(gnutls_pubkey_t <var class="var">key</var>)</code><a class="copiable-link" href="#index-gnutls_005fpubkey_005fverify_005fparams"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: should contain a <code class="code">gnutls_pubkey_t</code>  type
</p>
<p>This function will verify the public key parameters.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fregister_005fcustom_005furl-1"><span>gnutls_register_custom_url<a class="copiable-link" href="#gnutls_005fregister_005fcustom_005furl-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fregister_005fcustom_005furl"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fregister_005fcustom_005furl-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_register_custom_url</strong> <code class="def-code-arguments">(const gnutls_custom_url_st * <var class="var">st</var>)</code><a class="copiable-link" href="#index-gnutls_005fregister_005fcustom_005furl-1"> &para;</a></span></dt>
<dd><p><var class="var">st</var>: A <code class="code">gnutls_custom_url_st</code>  structure
</p>
<p>Register a custom URL. This will affect the following functions:
<code class="code">gnutls_url_is_supported()</code> , <code class="code">gnutls_privkey_import_url()</code> ,
gnutls_pubkey_import_url, <code class="code">gnutls_x509_crt_import_url()</code>  
and all functions that depend on
them, e.g., <code class="code">gnutls_certificate_set_x509_key_file2()</code> .
</p>
<p>The provided structure and callback functions must be valid throughout
the lifetime of the process. The registration of an existing URL type
will fail with <code class="code">GNUTLS_E_INVALID_REQUEST</code> . Since GnuTLS 3.5.0 this function
can be used to override the builtin URLs.
</p>
<p>This function is not thread safe.
</p>
<p><strong class="strong">Returns:</strong> returns zero if the given structure was imported or a negative value otherwise.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsystem_005fkey_005fadd_005fx509-1"><span>gnutls_system_key_add_x509<a class="copiable-link" href="#gnutls_005fsystem_005fkey_005fadd_005fx509-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsystem_005fkey_005fadd_005fx509"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsystem_005fkey_005fadd_005fx509"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_system_key_add_x509</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, gnutls_x509_privkey_t <var class="var">privkey</var>, const char * <var class="var">label</var>, char ** <var class="var">cert_url</var>, char ** <var class="var">key_url</var>)</code><a class="copiable-link" href="#index-gnutls_005fsystem_005fkey_005fadd_005fx509"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: the certificate to be added
</p>
<p><var class="var">privkey</var>: the key to be added
</p>
<p><var class="var">label</var>: the friendly name to describe the key
</p>
<p><var class="var">cert_url</var>: if non-NULL it will contain an allocated value with the certificate URL
</p>
<p><var class="var">key_url</var>: if non-NULL it will contain an allocated value with the key URL
</p>
<p>This function will added the given key and certificate pair,
to the system list.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsystem_005fkey_005fdelete-1"><span>gnutls_system_key_delete<a class="copiable-link" href="#gnutls_005fsystem_005fkey_005fdelete-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsystem_005fkey_005fdelete"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsystem_005fkey_005fdelete"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_system_key_delete</strong> <code class="def-code-arguments">(const char * <var class="var">cert_url</var>, const char * <var class="var">key_url</var>)</code><a class="copiable-link" href="#index-gnutls_005fsystem_005fkey_005fdelete"> &para;</a></span></dt>
<dd><p><var class="var">cert_url</var>: the URL of the certificate
</p>
<p><var class="var">key_url</var>: the URL of the key
</p>
<p>This function will delete the key and certificate pair.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsystem_005fkey_005fiter_005fdeinit-1"><span>gnutls_system_key_iter_deinit<a class="copiable-link" href="#gnutls_005fsystem_005fkey_005fiter_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsystem_005fkey_005fiter_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsystem_005fkey_005fiter_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_system_key_iter_deinit</strong> <code class="def-code-arguments">(gnutls_system_key_iter_t <var class="var">iter</var>)</code><a class="copiable-link" href="#index-gnutls_005fsystem_005fkey_005fiter_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">iter</var>: an iterator of system keys
</p>
<p>This function will deinitialize the iterator.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fsystem_005fkey_005fiter_005fget_005finfo-1"><span>gnutls_system_key_iter_get_info<a class="copiable-link" href="#gnutls_005fsystem_005fkey_005fiter_005fget_005finfo-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fsystem_005fkey_005fiter_005fget_005finfo"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fsystem_005fkey_005fiter_005fget_005finfo-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_system_key_iter_get_info</strong> <code class="def-code-arguments">(gnutls_system_key_iter_t * <var class="var">iter</var>, unsigned <var class="var">cert_type</var>, char ** <var class="var">cert_url</var>, char ** <var class="var">key_url</var>, char ** <var class="var">label</var>, gnutls_datum_t * <var class="var">der</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fsystem_005fkey_005fiter_005fget_005finfo-1"> &para;</a></span></dt>
<dd><p><var class="var">iter</var>: an iterator of the system keys (must be set to <code class="code">NULL</code>  initially)
</p>
<p><var class="var">cert_type</var>: A value of gnutls_certificate_type_t which indicates the type of certificate to look for
</p>
<p><var class="var">cert_url</var>: The certificate URL of the pair (may be <code class="code">NULL</code> )
</p>
<p><var class="var">key_url</var>: The key URL of the pair (may be <code class="code">NULL</code> )
</p>
<p><var class="var">label</var>: The friendly name (if any) of the pair (may be <code class="code">NULL</code> )
</p>
<p><var class="var">der</var>: if non-NULL the DER data of the certificate
</p>
<p><var class="var">flags</var>: should be zero
</p>
<p>This function will return on each call a certificate
and key pair URLs, as well as a label associated with them,
and the DER-encoded certificate. When the iteration is complete it will
return <code class="code">GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE</code> .
</p>
<p>Typically  <code class="code">cert_type</code> should be <code class="code">GNUTLS_CRT_X509</code> .
</p>
<p>All values set are allocated and must be cleared using <code class="code">gnutls_free()</code> ,
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrl_005fprivkey_005fsign-1"><span>gnutls_x509_crl_privkey_sign<a class="copiable-link" href="#gnutls_005fx509_005fcrl_005fprivkey_005fsign-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrl_005fprivkey_005fsign"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrl_005fprivkey_005fsign-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crl_privkey_sign</strong> <code class="def-code-arguments">(gnutls_x509_crl_t <var class="var">crl</var>, gnutls_x509_crt_t <var class="var">issuer</var>, gnutls_privkey_t <var class="var">issuer_key</var>, gnutls_digest_algorithm_t <var class="var">dig</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrl_005fprivkey_005fsign-1"> &para;</a></span></dt>
<dd><p><var class="var">crl</var>: should contain a gnutls_x509_crl_t type
</p>
<p><var class="var">issuer</var>: is the certificate of the certificate issuer
</p>
<p><var class="var">issuer_key</var>: holds the issuer&rsquo;s private key
</p>
<p><var class="var">dig</var>: The message digest to use. GNUTLS_DIG_SHA256 is the safe choice unless you know what you&rsquo;re doing.
</p>
<p><var class="var">flags</var>: must be 0
</p>
<p>This function will sign the CRL with the issuer&rsquo;s private key, and
will copy the issuer&rsquo;s information into the CRL.
</p>
<p>This must be the last step in a certificate CRL since all
the previously set parameters are now signed.
</p>
<p>A known limitation of this function is, that a newly-signed CRL will not
be fully functional (e.g., for signature verification), until it
is exported an re-imported.
</p>
<p>After GnuTLS 3.6.1 the value of  <code class="code">dig</code> may be <code class="code">GNUTLS_DIG_UNKNOWN</code> ,
and in that case, a suitable but reasonable for the key algorithm will be selected.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p>Since 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fprivkey_005fsign-1"><span>gnutls_x509_crq_privkey_sign<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fprivkey_005fsign-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fprivkey_005fsign"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fprivkey_005fsign"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_privkey_sign</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, gnutls_privkey_t <var class="var">key</var>, gnutls_digest_algorithm_t <var class="var">dig</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fprivkey_005fsign"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: should contain a <code class="code">gnutls_x509_crq_t</code>  type
</p>
<p><var class="var">key</var>: holds a private key
</p>
<p><var class="var">dig</var>: The message digest to use, i.e., <code class="code">GNUTLS_DIG_SHA1</code> 
</p>
<p><var class="var">flags</var>: must be 0
</p>
<p>This function will sign the certificate request with a private key.
This must be the same key as the one used in
<code class="code">gnutls_x509_crt_set_key()</code>  since a certificate request is self
signed.
</p>
<p>This must be the last step in a certificate request generation
since all the previously set parameters are now signed.
</p>
<p>A known limitation of this function is, that a newly-signed request will not
be fully functional (e.g., for signature verification), until it
is exported an re-imported.
</p>
<p>After GnuTLS 3.6.1 the value of  <code class="code">dig</code> may be <code class="code">GNUTLS_DIG_UNKNOWN</code> ,
and in that case, a suitable but reasonable for the key algorithm will be selected.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
<code class="code">GNUTLS_E_ASN1_VALUE_NOT_FOUND</code>  is returned if you didn&rsquo;t set all
information in the certificate request (e.g., the version using
<code class="code">gnutls_x509_crq_set_version()</code> ).
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrq_005fset_005fpubkey-1"><span>gnutls_x509_crq_set_pubkey<a class="copiable-link" href="#gnutls_005fx509_005fcrq_005fset_005fpubkey-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrq_005fset_005fpubkey"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrq_005fset_005fpubkey-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crq_set_pubkey</strong> <code class="def-code-arguments">(gnutls_x509_crq_t <var class="var">crq</var>, gnutls_pubkey_t <var class="var">key</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrq_005fset_005fpubkey-1"> &para;</a></span></dt>
<dd><p><var class="var">crq</var>: should contain a <code class="code">gnutls_x509_crq_t</code>  type
</p>
<p><var class="var">key</var>: holds a public key
</p>
<p>This function will set the public parameters from the given public
key to the request. The  <code class="code">key</code> can be deallocated after that.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fprivkey_005fsign-1"><span>gnutls_x509_crt_privkey_sign<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fprivkey_005fsign-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fprivkey_005fsign"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fprivkey_005fsign"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_privkey_sign</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, gnutls_x509_crt_t <var class="var">issuer</var>, gnutls_privkey_t <var class="var">issuer_key</var>, gnutls_digest_algorithm_t <var class="var">dig</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fprivkey_005fsign"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: a certificate of type <code class="code">gnutls_x509_crt_t</code> 
</p>
<p><var class="var">issuer</var>: is the certificate of the certificate issuer
</p>
<p><var class="var">issuer_key</var>: holds the issuer&rsquo;s private key
</p>
<p><var class="var">dig</var>: The message digest to use, <code class="code">GNUTLS_DIG_SHA256</code>  is a safe choice
</p>
<p><var class="var">flags</var>: must be 0
</p>
<p>This function will sign the certificate with the issuer&rsquo;s private key, and
will copy the issuer&rsquo;s information into the certificate.
</p>
<p>This must be the last step in a certificate generation since all
the previously set parameters are now signed.
</p>
<p>A known limitation of this function is, that a newly-signed certificate will not
be fully functional (e.g., for signature verification), until it
is exported an re-imported.
</p>
<p>After GnuTLS 3.6.1 the value of  <code class="code">dig</code> may be <code class="code">GNUTLS_DIG_UNKNOWN</code> ,
and in that case, a suitable but reasonable for the key algorithm will be selected.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fset_005fpubkey-1"><span>gnutls_x509_crt_set_pubkey<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fset_005fpubkey-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fset_005fpubkey"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fset_005fpubkey-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_set_pubkey</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, gnutls_pubkey_t <var class="var">key</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fset_005fpubkey-1"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: should contain a <code class="code">gnutls_x509_crt_t</code>  type
</p>
<p><var class="var">key</var>: holds a public key
</p>
<p>This function will set the public parameters from the given public
key to the certificate. The  <code class="code">key</code> can be deallocated after that.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>


<hr>
</div>
<div class="section-level-extent" id="Socket-specific-API">
<div class="nav-panel">
<p>
Next: <a href="#DANE-API" accesskey="n" rel="next">DANE API</a>, Previous: <a href="#Abstract-key-API" accesskey="p" rel="prev">Abstract key API</a>, Up: <a href="#API-reference" accesskey="u" rel="up">API reference</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Socket-specific-API-1"><span>E.10 Socket specific API<a class="copiable-link" href="#Socket-specific-API-1"> &para;</a></span></h3>

<p>The prototypes for the following functions lie in
<samp class="file">gnutls/socket.h</samp>.
</p>
<h4 class="subheading" id="gnutls_005ftransport_005fset_005ffastopen-1"><span>gnutls_transport_set_fastopen<a class="copiable-link" href="#gnutls_005ftransport_005fset_005ffastopen-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005ftransport_005fset_005ffastopen"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005ftransport_005fset_005ffastopen-1"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_transport_set_fastopen</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>, int <var class="var">fd</var>, struct sockaddr * <var class="var">connect_addr</var>, socklen_t <var class="var">connect_addrlen</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005ftransport_005fset_005ffastopen-1"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p><var class="var">fd</var>: is the session&rsquo;s socket descriptor
</p>
<p><var class="var">connect_addr</var>: is the address we want to connect to
</p>
<p><var class="var">connect_addrlen</var>: is the length of  <code class="code">connect_addr</code> 
</p>
<p><var class="var">flags</var>: must be zero
</p>
<p>Enables TCP Fast Open (TFO) for the specified TLS client session.
That means that TCP connection establishment and the transmission
of the first TLS client hello packet are combined. The
peer&rsquo;s address must be  specified in  <code class="code">connect_addr</code> and  <code class="code">connect_addrlen</code> ,
and the socket specified by  <code class="code">fd</code> should not be connected.
</p>
<p>TFO only works for TCP sockets of type AF_INET and AF_INET6.
If the OS doesn&rsquo;t support TCP fast open this function will result
to gnutls using <code class="code">connect()</code>  transparently during the first write.
</p>
<p><strong class="strong">Note:</strong> This function overrides all the transport callback functions.
If this is undesirable, TCP Fast Open must be implemented on the user
callback functions without calling this function. When using
this function, transport callbacks must not be set, and 
<code class="code">gnutls_transport_set_ptr()</code>  or <code class="code">gnutls_transport_set_int()</code> 
must not be called.
</p>
<p>On GNU/Linux TFO has to be enabled at the system layer, that is
in /proc/sys/net/ipv4/tcp_fastopen, bit 0 has to be set.
</p>
<p>This function has no effect on server sessions.
</p>
<p><strong class="strong">Since:</strong> 3.5.3
</p></dd></dl>


<hr>
</div>
<div class="section-level-extent" id="DANE-API">
<div class="nav-panel">
<p>
Next: <a href="#Cryptographic-API" accesskey="n" rel="next">Cryptographic API</a>, Previous: <a href="#Socket-specific-API" accesskey="p" rel="prev">Socket specific API</a>, Up: <a href="#API-reference" accesskey="u" rel="up">API reference</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="DANE-API-1"><span>E.11 DANE API<a class="copiable-link" href="#DANE-API-1"> &para;</a></span></h3>

<p>The following functions are to be used for DANE certificate verification.
Their prototypes lie in <samp class="file">gnutls/dane.h</samp>. Note that you need to link
with the <code class="code">libgnutls-dane</code> library to use them.
</p>

<h4 class="subheading" id="dane_005fcert_005ftype_005fname-1"><span>dane_cert_type_name<a class="copiable-link" href="#dane_005fcert_005ftype_005fname-1"> &para;</a></span></h4>
<a class="anchor" id="dane_005fcert_005ftype_005fname"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-dane_005fcert_005ftype_005fname"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">dane_cert_type_name</strong> <code class="def-code-arguments">(dane_cert_type_t <var class="var">type</var>)</code><a class="copiable-link" href="#index-dane_005fcert_005ftype_005fname"> &para;</a></span></dt>
<dd><p><var class="var">type</var>: is a DANE match type
</p>
<p>Convert a <code class="code">dane_cert_type_t</code>  value to a string.
</p>
<p><strong class="strong">Returns:</strong> a string that contains the name of the specified
type, or <code class="code">NULL</code> .
</p></dd></dl>

<h4 class="subheading" id="dane_005fcert_005fusage_005fname-1"><span>dane_cert_usage_name<a class="copiable-link" href="#dane_005fcert_005fusage_005fname-1"> &para;</a></span></h4>
<a class="anchor" id="dane_005fcert_005fusage_005fname"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-dane_005fcert_005fusage_005fname"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">dane_cert_usage_name</strong> <code class="def-code-arguments">(dane_cert_usage_t <var class="var">usage</var>)</code><a class="copiable-link" href="#index-dane_005fcert_005fusage_005fname"> &para;</a></span></dt>
<dd><p><var class="var">usage</var>: is a DANE certificate usage
</p>
<p>Convert a <code class="code">dane_cert_usage_t</code>  value to a string.
</p>
<p><strong class="strong">Returns:</strong> a string that contains the name of the specified
type, or <code class="code">NULL</code> .
</p></dd></dl>

<h4 class="subheading" id="dane_005fmatch_005ftype_005fname-1"><span>dane_match_type_name<a class="copiable-link" href="#dane_005fmatch_005ftype_005fname-1"> &para;</a></span></h4>
<a class="anchor" id="dane_005fmatch_005ftype_005fname"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-dane_005fmatch_005ftype_005fname"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">dane_match_type_name</strong> <code class="def-code-arguments">(dane_match_type_t <var class="var">type</var>)</code><a class="copiable-link" href="#index-dane_005fmatch_005ftype_005fname"> &para;</a></span></dt>
<dd><p><var class="var">type</var>: is a DANE match type
</p>
<p>Convert a <code class="code">dane_match_type_t</code>  value to a string.
</p>
<p><strong class="strong">Returns:</strong> a string that contains the name of the specified
type, or <code class="code">NULL</code> .
</p></dd></dl>

<h4 class="subheading" id="dane_005fquery_005fdata-1"><span>dane_query_data<a class="copiable-link" href="#dane_005fquery_005fdata-1"> &para;</a></span></h4>
<a class="anchor" id="dane_005fquery_005fdata"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-dane_005fquery_005fdata"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">dane_query_data</strong> <code class="def-code-arguments">(dane_query_t <var class="var">q</var>, unsigned int <var class="var">idx</var>, unsigned int * <var class="var">usage</var>, unsigned int * <var class="var">type</var>, unsigned int * <var class="var">match</var>, gnutls_datum_t * <var class="var">data</var>)</code><a class="copiable-link" href="#index-dane_005fquery_005fdata"> &para;</a></span></dt>
<dd><p><var class="var">q</var>: The query result structure
</p>
<p><var class="var">idx</var>: The index of the query response.
</p>
<p><var class="var">usage</var>: The certificate usage (see <code class="code">dane_cert_usage_t</code> )
</p>
<p><var class="var">type</var>: The certificate type (see <code class="code">dane_cert_type_t</code> )
</p>
<p><var class="var">match</var>: The DANE matching type (see <code class="code">dane_match_type_t</code> )
</p>
<p><var class="var">data</var>: The DANE data.
</p>
<p>This function will provide the DANE data from the query
response.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">DANE_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="dane_005fquery_005fdeinit-1"><span>dane_query_deinit<a class="copiable-link" href="#dane_005fquery_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="dane_005fquery_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-dane_005fquery_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">dane_query_deinit</strong> <code class="def-code-arguments">(dane_query_t <var class="var">q</var>)</code><a class="copiable-link" href="#index-dane_005fquery_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">q</var>: The structure to be deinitialized
</p>
<p>This function will deinitialize a DANE query result structure.
</p></dd></dl>

<h4 class="subheading" id="dane_005fquery_005fentries-1"><span>dane_query_entries<a class="copiable-link" href="#dane_005fquery_005fentries-1"> &para;</a></span></h4>
<a class="anchor" id="dane_005fquery_005fentries"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-dane_005fquery_005fentries"><span class="category-def">Function: </span><span><code class="def-type">unsigned int</code> <strong class="def-name">dane_query_entries</strong> <code class="def-code-arguments">(dane_query_t <var class="var">q</var>)</code><a class="copiable-link" href="#index-dane_005fquery_005fentries"> &para;</a></span></dt>
<dd><p><var class="var">q</var>: The query result structure
</p>
<p>This function will return the number of entries in a query.
</p>
<p><strong class="strong">Returns:</strong> The number of entries.
</p></dd></dl>

<h4 class="subheading" id="dane_005fquery_005fstatus-1"><span>dane_query_status<a class="copiable-link" href="#dane_005fquery_005fstatus-1"> &para;</a></span></h4>
<a class="anchor" id="dane_005fquery_005fstatus"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-dane_005fquery_005fstatus"><span class="category-def">Function: </span><span><code class="def-type">dane_query_status_t</code> <strong class="def-name">dane_query_status</strong> <code class="def-code-arguments">(dane_query_t <var class="var">q</var>)</code><a class="copiable-link" href="#index-dane_005fquery_005fstatus"> &para;</a></span></dt>
<dd><p><var class="var">q</var>: The query result structure
</p>
<p>This function will return the status of the query response.
See <code class="code">dane_query_status_t</code>  for the possible types.
</p>
<p><strong class="strong">Returns:</strong> The status type.
</p></dd></dl>

<h4 class="subheading" id="dane_005fquery_005ftlsa-1"><span>dane_query_tlsa<a class="copiable-link" href="#dane_005fquery_005ftlsa-1"> &para;</a></span></h4>
<a class="anchor" id="dane_005fquery_005ftlsa"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-dane_005fquery_005ftlsa"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">dane_query_tlsa</strong> <code class="def-code-arguments">(dane_state_t <var class="var">s</var>, dane_query_t * <var class="var">r</var>, const char * <var class="var">host</var>, const char * <var class="var">proto</var>, unsigned int <var class="var">port</var>)</code><a class="copiable-link" href="#index-dane_005fquery_005ftlsa"> &para;</a></span></dt>
<dd><p><var class="var">s</var>: The DANE state structure
</p>
<p><var class="var">r</var>: A structure to place the result
</p>
<p><var class="var">host</var>: The host name to resolve.
</p>
<p><var class="var">proto</var>: The protocol type (tcp, udp, etc.)
</p>
<p><var class="var">port</var>: The service port number (eg. 443).
</p>
<p>This function will query the DNS server for the TLSA (DANE)
data for the given host.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">DANE_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="dane_005fquery_005fto_005fraw_005ftlsa-1"><span>dane_query_to_raw_tlsa<a class="copiable-link" href="#dane_005fquery_005fto_005fraw_005ftlsa-1"> &para;</a></span></h4>
<a class="anchor" id="dane_005fquery_005fto_005fraw_005ftlsa"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-dane_005fquery_005fto_005fraw_005ftlsa"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">dane_query_to_raw_tlsa</strong> <code class="def-code-arguments">(dane_query_t <var class="var">q</var>, unsigned int * <var class="var">data_entries</var>, char *** <var class="var">dane_data</var>, int ** <var class="var">dane_data_len</var>, int * <var class="var">secure</var>, int * <var class="var">bogus</var>)</code><a class="copiable-link" href="#index-dane_005fquery_005fto_005fraw_005ftlsa"> &para;</a></span></dt>
<dd><p><var class="var">q</var>: The query result structure
</p>
<p><var class="var">data_entries</var>: Pointer set to the number of entries in the query
</p>
<p><var class="var">dane_data</var>: Pointer to contain an array of DNS rdata items, terminated with a NULL pointer;
caller must guarantee that the referenced data remains
valid until <code class="code">dane_query_deinit()</code>  is called.
</p>
<p><var class="var">dane_data_len</var>: Pointer to contain the length n bytes of the dane_data items
</p>
<p><var class="var">secure</var>: Pointer set true if the result is validated securely, false if
validation failed or the domain queried has no security info
</p>
<p><var class="var">bogus</var>: Pointer set true if the result was not secure due to a security failure
</p>
<p>This function will provide the DANE data from the query
response.
</p>
<p>The pointers dane_data and dane_data_len are allocated with <code class="code">gnutls_malloc()</code> 
to contain the data from the query result structure (individual
 <code class="code">dane_data</code> items simply point to the original data and are not allocated separately).
The returned  <code class="code">dane_data</code> are only valid during the lifetime of  <code class="code">q</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">DANE_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="dane_005fraw_005ftlsa-1"><span>dane_raw_tlsa<a class="copiable-link" href="#dane_005fraw_005ftlsa-1"> &para;</a></span></h4>
<a class="anchor" id="dane_005fraw_005ftlsa"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-dane_005fraw_005ftlsa"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">dane_raw_tlsa</strong> <code class="def-code-arguments">(dane_state_t <var class="var">s</var>, dane_query_t * <var class="var">r</var>, char *const * <var class="var">dane_data</var>, const int * <var class="var">dane_data_len</var>, int <var class="var">secure</var>, int <var class="var">bogus</var>)</code><a class="copiable-link" href="#index-dane_005fraw_005ftlsa"> &para;</a></span></dt>
<dd><p><var class="var">s</var>: The DANE state structure
</p>
<p><var class="var">r</var>: A structure to place the result
</p>
<p><var class="var">dane_data</var>: array of DNS rdata items, terminated with a NULL pointer;
caller must guarantee that the referenced data remains
valid until <code class="code">dane_query_deinit()</code>  is called.
</p>
<p><var class="var">dane_data_len</var>: the length n bytes of the dane_data items
</p>
<p><var class="var">secure</var>: true if the result is validated securely, false if
validation failed or the domain queried has no security info
</p>
<p><var class="var">bogus</var>: if the result was not secure (secure = 0) due to a security failure,
and the result is due to a security failure, bogus is true.
</p>
<p>This function will fill in the TLSA (DANE) structure from
the given raw DNS record data. The  <code class="code">dane_data</code> must be valid
during the lifetime of the query.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">DANE_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="dane_005fstate_005fdeinit-1"><span>dane_state_deinit<a class="copiable-link" href="#dane_005fstate_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="dane_005fstate_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-dane_005fstate_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">dane_state_deinit</strong> <code class="def-code-arguments">(dane_state_t <var class="var">s</var>)</code><a class="copiable-link" href="#index-dane_005fstate_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">s</var>: The structure to be deinitialized
</p>
<p>This function will deinitialize a DANE query structure.
</p></dd></dl>

<h4 class="subheading" id="dane_005fstate_005finit-1"><span>dane_state_init<a class="copiable-link" href="#dane_005fstate_005finit-1"> &para;</a></span></h4>
<a class="anchor" id="dane_005fstate_005finit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-dane_005fstate_005finit"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">dane_state_init</strong> <code class="def-code-arguments">(dane_state_t * <var class="var">s</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-dane_005fstate_005finit"> &para;</a></span></dt>
<dd><p><var class="var">s</var>: The structure to be initialized
</p>
<p><var class="var">flags</var>: flags from the <code class="code">dane_state_flags</code>  enumeration
</p>
<p>This function will initialize the backend resolver. It is
intended to be used in scenarios where multiple resolvings
occur, to optimize against multiple re-initializations.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">DANE_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="dane_005fstate_005fset_005fdlv_005ffile-1"><span>dane_state_set_dlv_file<a class="copiable-link" href="#dane_005fstate_005fset_005fdlv_005ffile-1"> &para;</a></span></h4>
<a class="anchor" id="dane_005fstate_005fset_005fdlv_005ffile"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-dane_005fstate_005fset_005fdlv_005ffile"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">dane_state_set_dlv_file</strong> <code class="def-code-arguments">(dane_state_t <var class="var">s</var>, const char * <var class="var">file</var>)</code><a class="copiable-link" href="#index-dane_005fstate_005fset_005fdlv_005ffile"> &para;</a></span></dt>
<dd><p><var class="var">s</var>: The structure to be deinitialized
</p>
<p><var class="var">file</var>: The file holding the DLV keys.
</p>
<p>This function will set a file with trusted keys
for DLV (DNSSEC Lookaside Validation).
</p></dd></dl>

<h4 class="subheading" id="dane_005fstrerror-1"><span>dane_strerror<a class="copiable-link" href="#dane_005fstrerror-1"> &para;</a></span></h4>
<a class="anchor" id="dane_005fstrerror"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-dane_005fstrerror"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">dane_strerror</strong> <code class="def-code-arguments">(int <var class="var">error</var>)</code><a class="copiable-link" href="#index-dane_005fstrerror"> &para;</a></span></dt>
<dd><p><var class="var">error</var>: is a DANE error code, a negative error code
</p>
<p>This function is similar to strerror.  The difference is that it
accepts an error number returned by a gnutls function; In case of
an unknown error a descriptive string is sent instead of <code class="code">NULL</code> .
</p>
<p>Error codes are always a negative error code.
</p>
<p><strong class="strong">Returns:</strong> A string explaining the DANE error message.
</p></dd></dl>

<h4 class="subheading" id="dane_005fverification_005fstatus_005fprint-1"><span>dane_verification_status_print<a class="copiable-link" href="#dane_005fverification_005fstatus_005fprint-1"> &para;</a></span></h4>
<a class="anchor" id="dane_005fverification_005fstatus_005fprint"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-dane_005fverification_005fstatus_005fprint"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">dane_verification_status_print</strong> <code class="def-code-arguments">(unsigned int <var class="var">status</var>, gnutls_datum_t * <var class="var">out</var>, unsigned int <var class="var">flags</var>)</code><a class="copiable-link" href="#index-dane_005fverification_005fstatus_005fprint"> &para;</a></span></dt>
<dd><p><var class="var">status</var>: The status flags to be printed
</p>
<p><var class="var">out</var>: Newly allocated datum with (0) terminated string.
</p>
<p><var class="var">flags</var>: should be zero
</p>
<p>This function will pretty print the status of a verification
process &ndash; eg. the one obtained by <code class="code">dane_verify_crt()</code> .
</p>
<p>The output  <code class="code">out</code> needs to be deallocated using <code class="code">gnutls_free()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p></dd></dl>

<h4 class="subheading" id="dane_005fverify_005fcrt-1"><span>dane_verify_crt<a class="copiable-link" href="#dane_005fverify_005fcrt-1"> &para;</a></span></h4>
<a class="anchor" id="dane_005fverify_005fcrt"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-dane_005fverify_005fcrt-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">dane_verify_crt</strong> <code class="def-code-arguments">(dane_state_t <var class="var">s</var>, const gnutls_datum_t * <var class="var">chain</var>, unsigned <var class="var">chain_size</var>, gnutls_certificate_type_t <var class="var">chain_type</var>, const char * <var class="var">hostname</var>, const char * <var class="var">proto</var>, unsigned int <var class="var">port</var>, unsigned int <var class="var">sflags</var>, unsigned int <var class="var">vflags</var>, unsigned int * <var class="var">verify</var>)</code><a class="copiable-link" href="#index-dane_005fverify_005fcrt-1"> &para;</a></span></dt>
<dd><p><var class="var">s</var>: A DANE state structure (may be NULL)
</p>
<p><var class="var">chain</var>: A certificate chain
</p>
<p><var class="var">chain_size</var>: The size of the chain
</p>
<p><var class="var">chain_type</var>: The type of the certificate chain
</p>
<p><var class="var">hostname</var>: The hostname associated with the chain
</p>
<p><var class="var">proto</var>: The protocol of the service connecting (e.g. tcp)
</p>
<p><var class="var">port</var>: The port of the service connecting (e.g. 443)
</p>
<p><var class="var">sflags</var>: Flags for the initialization of  <code class="code">s</code> (if NULL)
</p>
<p><var class="var">vflags</var>: Verification flags; an OR&rsquo;ed list of <code class="code">dane_verify_flags_t</code> .
</p>
<p><var class="var">verify</var>: An OR&rsquo;ed list of <code class="code">dane_verify_status_t</code> .
</p>
<p>This function will verify the given certificate chain against the
CA constrains and/or the certificate available via DANE.
If no information via DANE can be obtained the flag <code class="code">DANE_VERIFY_NO_DANE_INFO</code> 
is set. If a DNSSEC signature is not available for the DANE
record then the verify flag <code class="code">DANE_VERIFY_NO_DNSSEC_DATA</code>  is set.
</p>
<p>Due to the many possible options of DANE, there is no single threat
model countered. When notifying the user about DANE verification results
it may be better to mention: DANE verification did not reject the certificate,
rather than mentioning a successful DANE verification.
</p>
<p>Note that this function is designed to be run in addition to
PKIX - certificate chain - verification. To be run independently
the <code class="code">DANE_VFLAG_ONLY_CHECK_EE_USAGE</code>  flag should be specified;
then the function will check whether the key of the peer matches the
key advertised in the DANE entry.
</p>
<p><strong class="strong">Returns:</strong> a negative error code on error and <code class="code">DANE_E_SUCCESS</code>  (0)
when the DANE entries were successfully parsed, irrespective of
whether they were verified (see  <code class="code">verify</code> for that information). If
no usable entries were encountered <code class="code">DANE_E_REQUESTED_DATA_NOT_AVAILABLE</code> 
will be returned.
</p></dd></dl>

<h4 class="subheading" id="dane_005fverify_005fcrt_005fraw-1"><span>dane_verify_crt_raw<a class="copiable-link" href="#dane_005fverify_005fcrt_005fraw-1"> &para;</a></span></h4>
<a class="anchor" id="dane_005fverify_005fcrt_005fraw"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-dane_005fverify_005fcrt_005fraw"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">dane_verify_crt_raw</strong> <code class="def-code-arguments">(dane_state_t <var class="var">s</var>, const gnutls_datum_t * <var class="var">chain</var>, unsigned <var class="var">chain_size</var>, gnutls_certificate_type_t <var class="var">chain_type</var>, dane_query_t <var class="var">r</var>, unsigned int <var class="var">sflags</var>, unsigned int <var class="var">vflags</var>, unsigned int * <var class="var">verify</var>)</code><a class="copiable-link" href="#index-dane_005fverify_005fcrt_005fraw"> &para;</a></span></dt>
<dd><p><var class="var">s</var>: A DANE state structure (may be NULL)
</p>
<p><var class="var">chain</var>: A certificate chain
</p>
<p><var class="var">chain_size</var>: The size of the chain
</p>
<p><var class="var">chain_type</var>: The type of the certificate chain
</p>
<p><var class="var">r</var>: DANE data to check against
</p>
<p><var class="var">sflags</var>: Flags for the initialization of  <code class="code">s</code> (if NULL)
</p>
<p><var class="var">vflags</var>: Verification flags; an OR&rsquo;ed list of <code class="code">dane_verify_flags_t</code> .
</p>
<p><var class="var">verify</var>: An OR&rsquo;ed list of <code class="code">dane_verify_status_t</code> .
</p>
<p>This is the low-level function of <code class="code">dane_verify_crt()</code> . See the
high level function for documentation.
</p>
<p>This function does not perform any resolving, it utilizes
cached entries from  <code class="code">r</code> .
</p>
<p><strong class="strong">Returns:</strong> a negative error code on error and <code class="code">DANE_E_SUCCESS</code>  (0)
when the DANE entries were successfully parsed, irrespective of
whether they were verified (see  <code class="code">verify</code> for that information). If
no usable entries were encountered <code class="code">DANE_E_REQUESTED_DATA_NOT_AVAILABLE</code> 
will be returned.
</p></dd></dl>

<h4 class="subheading" id="dane_005fverify_005fsession_005fcrt-1"><span>dane_verify_session_crt<a class="copiable-link" href="#dane_005fverify_005fsession_005fcrt-1"> &para;</a></span></h4>
<a class="anchor" id="dane_005fverify_005fsession_005fcrt"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-dane_005fverify_005fsession_005fcrt"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">dane_verify_session_crt</strong> <code class="def-code-arguments">(dane_state_t <var class="var">s</var>, gnutls_session_t <var class="var">session</var>, const char * <var class="var">hostname</var>, const char * <var class="var">proto</var>, unsigned int <var class="var">port</var>, unsigned int <var class="var">sflags</var>, unsigned int <var class="var">vflags</var>, unsigned int * <var class="var">verify</var>)</code><a class="copiable-link" href="#index-dane_005fverify_005fsession_005fcrt"> &para;</a></span></dt>
<dd><p><var class="var">s</var>: A DANE state structure (may be NULL)
</p>
<p><var class="var">session</var>: A gnutls session
</p>
<p><var class="var">hostname</var>: The hostname associated with the chain
</p>
<p><var class="var">proto</var>: The protocol of the service connecting (e.g. tcp)
</p>
<p><var class="var">port</var>: The port of the service connecting (e.g. 443)
</p>
<p><var class="var">sflags</var>: Flags for the initialization of  <code class="code">s</code> (if NULL)
</p>
<p><var class="var">vflags</var>: Verification flags; an OR&rsquo;ed list of <code class="code">dane_verify_flags_t</code> .
</p>
<p><var class="var">verify</var>: An OR&rsquo;ed list of <code class="code">dane_verify_status_t</code> .
</p>
<p>This function will verify session&rsquo;s certificate chain against the
CA constrains and/or the certificate available via DANE.
See <code class="code">dane_verify_crt()</code>  for more information.
</p>
<p>This will not verify the chain for validity; unless the DANE
verification is restricted to end certificates, this must be
be performed separately using <code class="code">gnutls_certificate_verify_peers3()</code> .
</p>
<p><strong class="strong">Returns:</strong> a negative error code on error and <code class="code">DANE_E_SUCCESS</code>  (0)
when the DANE entries were successfully parsed, irrespective of
whether they were verified (see  <code class="code">verify</code> for that information). If
no usable entries were encountered <code class="code">DANE_E_REQUESTED_DATA_NOT_AVAILABLE</code> 
will be returned.
</p></dd></dl>


<hr>
</div>
<div class="section-level-extent" id="Cryptographic-API">
<div class="nav-panel">
<p>
Next: <a href="#Compatibility-API" accesskey="n" rel="next">Compatibility API</a>, Previous: <a href="#DANE-API" accesskey="p" rel="prev">DANE API</a>, Up: <a href="#API-reference" accesskey="u" rel="up">API reference</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Cryptographic-API-1"><span>E.12 Cryptographic API<a class="copiable-link" href="#Cryptographic-API-1"> &para;</a></span></h3>

<p>The following functions are to be used for low-level cryptographic operations.
Their prototypes lie in <samp class="file">gnutls/crypto.h</samp>.
</p>
<p>Note that due to historic reasons several functions, (e.g.
<a class="ref" href="#gnutls_005fmac_005flist">gnutls_mac_list</a>, <a class="ref" href="#gnutls_005fmac_005fget_005fname">gnutls_mac_get_name</a>) of this API are part
of the <a class="ref" href="#Core-TLS-API">Core TLS API</a>.
</p>

<h4 class="subheading" id="gnutls_005faead_005fcipher_005fdecrypt-1"><span>gnutls_aead_cipher_decrypt<a class="copiable-link" href="#gnutls_005faead_005fcipher_005fdecrypt-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005faead_005fcipher_005fdecrypt"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005faead_005fcipher_005fdecrypt"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_aead_cipher_decrypt</strong> <code class="def-code-arguments">(gnutls_aead_cipher_hd_t <var class="var">handle</var>, const void * <var class="var">nonce</var>, size_t <var class="var">nonce_len</var>, const void * <var class="var">auth</var>, size_t <var class="var">auth_len</var>, size_t <var class="var">tag_size</var>, const void * <var class="var">ctext</var>, size_t <var class="var">ctext_len</var>, void * <var class="var">ptext</var>, size_t * <var class="var">ptext_len</var>)</code><a class="copiable-link" href="#index-gnutls_005faead_005fcipher_005fdecrypt"> &para;</a></span></dt>
<dd><p><var class="var">handle</var>: is a <code class="code">gnutls_aead_cipher_hd_t</code>  type.
</p>
<p><var class="var">nonce</var>: the nonce to set
</p>
<p><var class="var">nonce_len</var>: The length of the nonce
</p>
<p><var class="var">auth</var>: additional data to be authenticated
</p>
<p><var class="var">auth_len</var>: The length of the data
</p>
<p><var class="var">tag_size</var>: The size of the tag to use (use zero for the default)
</p>
<p><var class="var">ctext</var>: the data to decrypt (including the authentication tag)
</p>
<p><var class="var">ctext_len</var>: the length of data to decrypt (includes tag size)
</p>
<p><var class="var">ptext</var>: the decrypted data
</p>
<p><var class="var">ptext_len</var>: the length of decrypted data (initially must hold the maximum available size)
</p>
<p>This function will decrypt the given data using the algorithm
specified by the context. This function must be provided the complete
data to be decrypted, including the authentication tag. On several
AEAD ciphers, the authentication tag is appended to the ciphertext,
though this is not a general rule. This function will fail if
the tag verification fails.
</p>
<p><strong class="strong">Returns:</strong> Zero or a negative error code on verification failure or other error.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005faead_005fcipher_005fdecryptv2-1"><span>gnutls_aead_cipher_decryptv2<a class="copiable-link" href="#gnutls_005faead_005fcipher_005fdecryptv2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005faead_005fcipher_005fdecryptv2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005faead_005fcipher_005fdecryptv2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_aead_cipher_decryptv2</strong> <code class="def-code-arguments">(gnutls_aead_cipher_hd_t <var class="var">handle</var>, const void * <var class="var">nonce</var>, size_t <var class="var">nonce_len</var>, const giovec_t * <var class="var">auth_iov</var>, int <var class="var">auth_iovcnt</var>, const giovec_t * <var class="var">iov</var>, int <var class="var">iovcnt</var>, void * <var class="var">tag</var>, size_t <var class="var">tag_size</var>)</code><a class="copiable-link" href="#index-gnutls_005faead_005fcipher_005fdecryptv2"> &para;</a></span></dt>
<dd><p><var class="var">handle</var>: is a <code class="code">gnutls_aead_cipher_hd_t</code>  type.
</p>
<p><var class="var">nonce</var>: the nonce to set
</p>
<p><var class="var">nonce_len</var>: The length of the nonce
</p>
<p><var class="var">auth_iov</var>: additional data to be authenticated
</p>
<p><var class="var">auth_iovcnt</var>: The number of buffers in  <code class="code">auth_iov</code> 
</p>
<p><var class="var">iov</var>: the data to decrypt
</p>
<p><var class="var">iovcnt</var>: The number of buffers in  <code class="code">iov</code> 
</p>
<p><var class="var">tag</var>: The authentication tag
</p>
<p><var class="var">tag_size</var>: The size of the tag to use (use zero for the default)
</p>
<p>This is similar to <code class="code">gnutls_aead_cipher_decrypt()</code> , but it performs
in-place encryption on the provided data buffers.
</p>
<p><strong class="strong">Returns:</strong> Zero or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 3.6.10
</p></dd></dl>

<h4 class="subheading" id="gnutls_005faead_005fcipher_005fdeinit-1"><span>gnutls_aead_cipher_deinit<a class="copiable-link" href="#gnutls_005faead_005fcipher_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005faead_005fcipher_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005faead_005fcipher_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_aead_cipher_deinit</strong> <code class="def-code-arguments">(gnutls_aead_cipher_hd_t <var class="var">handle</var>)</code><a class="copiable-link" href="#index-gnutls_005faead_005fcipher_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">handle</var>: is a <code class="code">gnutls_aead_cipher_hd_t</code>  type.
</p>
<p>This function will deinitialize all resources occupied by the given
authenticated-encryption context.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005faead_005fcipher_005fencrypt-1"><span>gnutls_aead_cipher_encrypt<a class="copiable-link" href="#gnutls_005faead_005fcipher_005fencrypt-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005faead_005fcipher_005fencrypt"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005faead_005fcipher_005fencrypt"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_aead_cipher_encrypt</strong> <code class="def-code-arguments">(gnutls_aead_cipher_hd_t <var class="var">handle</var>, const void * <var class="var">nonce</var>, size_t <var class="var">nonce_len</var>, const void * <var class="var">auth</var>, size_t <var class="var">auth_len</var>, size_t <var class="var">tag_size</var>, const void * <var class="var">ptext</var>, size_t <var class="var">ptext_len</var>, void * <var class="var">ctext</var>, size_t * <var class="var">ctext_len</var>)</code><a class="copiable-link" href="#index-gnutls_005faead_005fcipher_005fencrypt"> &para;</a></span></dt>
<dd><p><var class="var">handle</var>: is a <code class="code">gnutls_aead_cipher_hd_t</code>  type.
</p>
<p><var class="var">nonce</var>: the nonce to set
</p>
<p><var class="var">nonce_len</var>: The length of the nonce
</p>
<p><var class="var">auth</var>: additional data to be authenticated
</p>
<p><var class="var">auth_len</var>: The length of the data
</p>
<p><var class="var">tag_size</var>: The size of the tag to use (use zero for the default)
</p>
<p><var class="var">ptext</var>: the data to encrypt
</p>
<p><var class="var">ptext_len</var>: The length of data to encrypt
</p>
<p><var class="var">ctext</var>: the encrypted data including authentication tag
</p>
<p><var class="var">ctext_len</var>: the length of encrypted data (initially must hold the maximum available size, including space for tag)
</p>
<p>This function will encrypt the given data using the algorithm
specified by the context. The output data will contain the
authentication tag.
</p>
<p><strong class="strong">Returns:</strong> Zero or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005faead_005fcipher_005fencryptv-1"><span>gnutls_aead_cipher_encryptv<a class="copiable-link" href="#gnutls_005faead_005fcipher_005fencryptv-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005faead_005fcipher_005fencryptv"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005faead_005fcipher_005fencryptv-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_aead_cipher_encryptv</strong> <code class="def-code-arguments">(gnutls_aead_cipher_hd_t <var class="var">handle</var>, const void * <var class="var">nonce</var>, size_t <var class="var">nonce_len</var>, const giovec_t * <var class="var">auth_iov</var>, int <var class="var">auth_iovcnt</var>, size_t <var class="var">tag_size</var>, const giovec_t * <var class="var">iov</var>, int <var class="var">iovcnt</var>, void * <var class="var">ctext</var>, size_t * <var class="var">ctext_len</var>)</code><a class="copiable-link" href="#index-gnutls_005faead_005fcipher_005fencryptv-1"> &para;</a></span></dt>
<dd><p><var class="var">handle</var>: is a <code class="code">gnutls_aead_cipher_hd_t</code>  type.
</p>
<p><var class="var">nonce</var>: the nonce to set
</p>
<p><var class="var">nonce_len</var>: The length of the nonce
</p>
<p><var class="var">auth_iov</var>: additional data to be authenticated
</p>
<p><var class="var">auth_iovcnt</var>: The number of buffers in  <code class="code">auth_iov</code> 
</p>
<p><var class="var">tag_size</var>: The size of the tag to use (use zero for the default)
</p>
<p><var class="var">iov</var>: the data to be encrypted
</p>
<p><var class="var">iovcnt</var>: The number of buffers in  <code class="code">iov</code> 
</p>
<p><var class="var">ctext</var>: the encrypted data including authentication tag
</p>
<p><var class="var">ctext_len</var>: the length of encrypted data (initially must hold the maximum available size, including space for tag)
</p>
<p>This function will encrypt the provided data buffers using the algorithm
specified by the context. The output data will contain the
authentication tag.
</p>
<p><strong class="strong">Returns:</strong> Zero or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 3.6.3
</p></dd></dl>

<h4 class="subheading" id="gnutls_005faead_005fcipher_005fencryptv2-1"><span>gnutls_aead_cipher_encryptv2<a class="copiable-link" href="#gnutls_005faead_005fcipher_005fencryptv2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005faead_005fcipher_005fencryptv2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005faead_005fcipher_005fencryptv2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_aead_cipher_encryptv2</strong> <code class="def-code-arguments">(gnutls_aead_cipher_hd_t <var class="var">handle</var>, const void * <var class="var">nonce</var>, size_t <var class="var">nonce_len</var>, const giovec_t * <var class="var">auth_iov</var>, int <var class="var">auth_iovcnt</var>, const giovec_t * <var class="var">iov</var>, int <var class="var">iovcnt</var>, void * <var class="var">tag</var>, size_t * <var class="var">tag_size</var>)</code><a class="copiable-link" href="#index-gnutls_005faead_005fcipher_005fencryptv2"> &para;</a></span></dt>
<dd><p><var class="var">handle</var>: is a <code class="code">gnutls_aead_cipher_hd_t</code>  type.
</p>
<p><var class="var">nonce</var>: the nonce to set
</p>
<p><var class="var">nonce_len</var>: The length of the nonce
</p>
<p><var class="var">auth_iov</var>: additional data to be authenticated
</p>
<p><var class="var">auth_iovcnt</var>: The number of buffers in  <code class="code">auth_iov</code> 
</p>
<p><var class="var">iov</var>: the data to be encrypted
</p>
<p><var class="var">iovcnt</var>: The number of buffers in  <code class="code">iov</code> 
</p>
<p><var class="var">tag</var>: The authentication tag
</p>
<p><var class="var">tag_size</var>: The size of the tag to use (use zero for the default)
</p>
<p>This is similar to <code class="code">gnutls_aead_cipher_encrypt()</code> , but it performs
in-place encryption on the provided data buffers.
</p>
<p><strong class="strong">Returns:</strong> Zero or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 3.6.10
</p></dd></dl>

<h4 class="subheading" id="gnutls_005faead_005fcipher_005finit-1"><span>gnutls_aead_cipher_init<a class="copiable-link" href="#gnutls_005faead_005fcipher_005finit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005faead_005fcipher_005finit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005faead_005fcipher_005finit"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_aead_cipher_init</strong> <code class="def-code-arguments">(gnutls_aead_cipher_hd_t * <var class="var">handle</var>, gnutls_cipher_algorithm_t <var class="var">cipher</var>, const gnutls_datum_t * <var class="var">key</var>)</code><a class="copiable-link" href="#index-gnutls_005faead_005fcipher_005finit"> &para;</a></span></dt>
<dd><p><var class="var">handle</var>: is a <code class="code">gnutls_aead_cipher_hd_t</code>  type.
</p>
<p><var class="var">cipher</var>: the authenticated-encryption algorithm to use
</p>
<p><var class="var">key</var>: The key to be used for encryption
</p>
<p>This function will initialize an context that can be used for
encryption/decryption of data. This will effectively use the
current crypto backend in use by gnutls or the cryptographic
accelerator in use.
</p>
<p><strong class="strong">Returns:</strong> Zero or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005faead_005fcipher_005fset_005fkey-1"><span>gnutls_aead_cipher_set_key<a class="copiable-link" href="#gnutls_005faead_005fcipher_005fset_005fkey-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005faead_005fcipher_005fset_005fkey"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005faead_005fcipher_005fset_005fkey"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_aead_cipher_set_key</strong> <code class="def-code-arguments">(gnutls_aead_cipher_hd_t <var class="var">handle</var>, const gnutls_datum_t * <var class="var">key</var>)</code><a class="copiable-link" href="#index-gnutls_005faead_005fcipher_005fset_005fkey"> &para;</a></span></dt>
<dd><p><var class="var">handle</var>: is a <code class="code">gnutls_aead_cipher_hd_t</code>  type.
</p>
<p><var class="var">key</var>: The key to be used for encryption
</p>
<p>This function will set a new key without re-initializing the
context.
</p>
<p><strong class="strong">Returns:</strong> Zero or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 3.7.5
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcipher_005fadd_005fauth-1"><span>gnutls_cipher_add_auth<a class="copiable-link" href="#gnutls_005fcipher_005fadd_005fauth-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcipher_005fadd_005fauth"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcipher_005fadd_005fauth"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_cipher_add_auth</strong> <code class="def-code-arguments">(gnutls_cipher_hd_t <var class="var">handle</var>, const void * <var class="var">ptext</var>, size_t <var class="var">ptext_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fcipher_005fadd_005fauth"> &para;</a></span></dt>
<dd><p><var class="var">handle</var>: is a <code class="code">gnutls_cipher_hd_t</code>  type
</p>
<p><var class="var">ptext</var>: the data to be authenticated
</p>
<p><var class="var">ptext_size</var>: the length of the data
</p>
<p>This function operates on authenticated encryption with
associated data (AEAD) ciphers and authenticate the
input data. This function can only be called once
and before any encryption operations.
</p>
<p><strong class="strong">Returns:</strong> Zero or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcipher_005fdecrypt-1"><span>gnutls_cipher_decrypt<a class="copiable-link" href="#gnutls_005fcipher_005fdecrypt-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcipher_005fdecrypt"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcipher_005fdecrypt"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_cipher_decrypt</strong> <code class="def-code-arguments">(gnutls_cipher_hd_t <var class="var">handle</var>, void * <var class="var">ctext</var>, size_t <var class="var">ctext_len</var>)</code><a class="copiable-link" href="#index-gnutls_005fcipher_005fdecrypt"> &para;</a></span></dt>
<dd><p><var class="var">handle</var>: is a <code class="code">gnutls_cipher_hd_t</code>  type
</p>
<p><var class="var">ctext</var>: the data to decrypt
</p>
<p><var class="var">ctext_len</var>: the length of data to decrypt
</p>
<p>This function will decrypt the given data using the algorithm
specified by the context.
</p>
<p>Note that in AEAD ciphers, this will not check the tag. You will
need to compare the tag sent with the value returned from <code class="code">gnutls_cipher_tag()</code> .
</p>
<p><strong class="strong">Returns:</strong> Zero or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 2.10.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcipher_005fdecrypt2-1"><span>gnutls_cipher_decrypt2<a class="copiable-link" href="#gnutls_005fcipher_005fdecrypt2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcipher_005fdecrypt2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcipher_005fdecrypt2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_cipher_decrypt2</strong> <code class="def-code-arguments">(gnutls_cipher_hd_t <var class="var">handle</var>, const void * <var class="var">ctext</var>, size_t <var class="var">ctext_len</var>, void * <var class="var">ptext</var>, size_t <var class="var">ptext_len</var>)</code><a class="copiable-link" href="#index-gnutls_005fcipher_005fdecrypt2"> &para;</a></span></dt>
<dd><p><var class="var">handle</var>: is a <code class="code">gnutls_cipher_hd_t</code>  type
</p>
<p><var class="var">ctext</var>: the data to decrypt
</p>
<p><var class="var">ctext_len</var>: the length of data to decrypt
</p>
<p><var class="var">ptext</var>: the decrypted data
</p>
<p><var class="var">ptext_len</var>: the available length for decrypted data
</p>
<p>This function will decrypt the given data using the algorithm
specified by the context. For block ciphers the  <code class="code">ctext_len</code> must be
a multiple of the block size. For the supported ciphers the plaintext
data length will equal the ciphertext size.
</p>
<p>Note that in AEAD ciphers, this will not check the tag. You will
need to compare the tag sent with the value returned from <code class="code">gnutls_cipher_tag()</code> .
</p>
<p><strong class="strong">Returns:</strong> Zero or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcipher_005fdecrypt3-1"><span>gnutls_cipher_decrypt3<a class="copiable-link" href="#gnutls_005fcipher_005fdecrypt3-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcipher_005fdecrypt3"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcipher_005fdecrypt3"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_cipher_decrypt3</strong> <code class="def-code-arguments">(gnutls_cipher_hd_t <var class="var">handle</var>, const void * <var class="var">ctext</var>, size_t <var class="var">ctext_len</var>, void * <var class="var">ptext</var>, size_t * <var class="var">ptext_len</var>, unsigned <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fcipher_005fdecrypt3"> &para;</a></span></dt>
<dd><p><var class="var">handle</var>: is a <code class="code">gnutls_cipher_hd_t</code>  type
</p>
<p><var class="var">ctext</var>: the data to decrypt
</p>
<p><var class="var">ctext_len</var>: the length of data to decrypt
</p>
<p><var class="var">ptext</var>: the decrypted data
</p>
<p><var class="var">ptext_len</var>: the available length for decrypted data
</p>
<p><var class="var">flags</var>: flags for padding
</p>
<p>This function will decrypt the given data using the algorithm
specified by the context. If  <code class="code">flags</code> is specified, padding for the
decrypted data will be removed accordingly and  <code class="code">ptext_len</code> will be
updated.
</p>
<p><strong class="strong">Returns:</strong> Zero or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 3.7.7
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcipher_005fdeinit-1"><span>gnutls_cipher_deinit<a class="copiable-link" href="#gnutls_005fcipher_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcipher_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcipher_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_cipher_deinit</strong> <code class="def-code-arguments">(gnutls_cipher_hd_t <var class="var">handle</var>)</code><a class="copiable-link" href="#index-gnutls_005fcipher_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">handle</var>: is a <code class="code">gnutls_cipher_hd_t</code>  type
</p>
<p>This function will deinitialize all resources occupied by the given
encryption context.
</p>
<p><strong class="strong">Since:</strong> 2.10.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcipher_005fencrypt-1"><span>gnutls_cipher_encrypt<a class="copiable-link" href="#gnutls_005fcipher_005fencrypt-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcipher_005fencrypt"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcipher_005fencrypt"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_cipher_encrypt</strong> <code class="def-code-arguments">(gnutls_cipher_hd_t <var class="var">handle</var>, void * <var class="var">ptext</var>, size_t <var class="var">ptext_len</var>)</code><a class="copiable-link" href="#index-gnutls_005fcipher_005fencrypt"> &para;</a></span></dt>
<dd><p><var class="var">handle</var>: is a <code class="code">gnutls_cipher_hd_t</code>  type
</p>
<p><var class="var">ptext</var>: the data to encrypt
</p>
<p><var class="var">ptext_len</var>: the length of data to encrypt
</p>
<p>This function will encrypt the given data using the algorithm
specified by the context.
</p>
<p><strong class="strong">Returns:</strong> Zero or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 2.10.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcipher_005fencrypt2-1"><span>gnutls_cipher_encrypt2<a class="copiable-link" href="#gnutls_005fcipher_005fencrypt2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcipher_005fencrypt2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcipher_005fencrypt2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_cipher_encrypt2</strong> <code class="def-code-arguments">(gnutls_cipher_hd_t <var class="var">handle</var>, const void * <var class="var">ptext</var>, size_t <var class="var">ptext_len</var>, void * <var class="var">ctext</var>, size_t <var class="var">ctext_len</var>)</code><a class="copiable-link" href="#index-gnutls_005fcipher_005fencrypt2"> &para;</a></span></dt>
<dd><p><var class="var">handle</var>: is a <code class="code">gnutls_cipher_hd_t</code>  type
</p>
<p><var class="var">ptext</var>: the data to encrypt
</p>
<p><var class="var">ptext_len</var>: the length of data to encrypt
</p>
<p><var class="var">ctext</var>: the encrypted data
</p>
<p><var class="var">ctext_len</var>: the available length for encrypted data
</p>
<p>This function will encrypt the given data using the algorithm
specified by the context. For block ciphers the  <code class="code">ptext_len</code> must be
a multiple of the block size. For the supported ciphers the encrypted
data length will equal the plaintext size.
</p>
<p><strong class="strong">Returns:</strong> Zero or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcipher_005fencrypt3-1"><span>gnutls_cipher_encrypt3<a class="copiable-link" href="#gnutls_005fcipher_005fencrypt3-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcipher_005fencrypt3"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcipher_005fencrypt3"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_cipher_encrypt3</strong> <code class="def-code-arguments">(gnutls_cipher_hd_t <var class="var">handle</var>, const void * <var class="var">ptext</var>, size_t <var class="var">ptext_len</var>, void * <var class="var">ctext</var>, size_t * <var class="var">ctext_len</var>, unsigned <var class="var">flags</var>)</code><a class="copiable-link" href="#index-gnutls_005fcipher_005fencrypt3"> &para;</a></span></dt>
<dd><p><var class="var">handle</var>: is a <code class="code">gnutls_cipher_hd_t</code>  type
</p>
<p><var class="var">ptext</var>: the data to encrypt
</p>
<p><var class="var">ptext_len</var>: the length of data to encrypt
</p>
<p><var class="var">ctext</var>: the encrypted data
</p>
<p><var class="var">ctext_len</var>: the length of encrypted data (initially must hold the maximum available size)
</p>
<p><var class="var">flags</var>: flags for padding
</p>
<p>This function will encrypt the given data using the algorithm
specified by the context. For block ciphers,  <code class="code">ptext_len</code> is
typically a multiple of the block size. If not, the caller can
instruct the function to pad the last block according to  <code class="code">flags</code> .
Currently, the only available padding scheme is
<code class="code">GNUTLS_CIPHER_PADDING_PKCS7</code> .
</p>
<p>If  <code class="code">ctext</code> is not <code class="code">NULL</code> , it must hold enough space to store
resulting cipher text. To check the required size, this function
can be called with  <code class="code">ctext</code> set to <code class="code">NULL</code> . Then  <code class="code">ctext_len</code> will be
updated without performing actual encryption.
</p>
<p><strong class="strong">Returns:</strong> Zero or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 3.7.7
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcipher_005fget_005fblock_005fsize-1"><span>gnutls_cipher_get_block_size<a class="copiable-link" href="#gnutls_005fcipher_005fget_005fblock_005fsize-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcipher_005fget_005fblock_005fsize"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcipher_005fget_005fblock_005fsize"><span class="category-def">Function: </span><span><code class="def-type">unsigned</code> <strong class="def-name">gnutls_cipher_get_block_size</strong> <code class="def-code-arguments">(gnutls_cipher_algorithm_t <var class="var">algorithm</var>)</code><a class="copiable-link" href="#index-gnutls_005fcipher_005fget_005fblock_005fsize"> &para;</a></span></dt>
<dd><p><var class="var">algorithm</var>: is an encryption algorithm
</p>

<p><strong class="strong">Returns:</strong> the block size of the encryption algorithm.
</p>
<p><strong class="strong">Since:</strong> 2.10.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcipher_005fget_005fiv_005fsize-1"><span>gnutls_cipher_get_iv_size<a class="copiable-link" href="#gnutls_005fcipher_005fget_005fiv_005fsize-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcipher_005fget_005fiv_005fsize"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcipher_005fget_005fiv_005fsize"><span class="category-def">Function: </span><span><code class="def-type">unsigned</code> <strong class="def-name">gnutls_cipher_get_iv_size</strong> <code class="def-code-arguments">(gnutls_cipher_algorithm_t <var class="var">algorithm</var>)</code><a class="copiable-link" href="#index-gnutls_005fcipher_005fget_005fiv_005fsize"> &para;</a></span></dt>
<dd><p><var class="var">algorithm</var>: is an encryption algorithm
</p>
<p>This function returns the size of the initialization vector (IV) for the
provided algorithm. For algorithms with variable size IV (e.g., AES-CCM),
the returned size will be the one used by TLS.
</p>
<p><strong class="strong">Returns:</strong> block size for encryption algorithm.
</p>
<p><strong class="strong">Since:</strong> 3.2.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcipher_005fget_005ftag_005fsize-1"><span>gnutls_cipher_get_tag_size<a class="copiable-link" href="#gnutls_005fcipher_005fget_005ftag_005fsize-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcipher_005fget_005ftag_005fsize"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcipher_005fget_005ftag_005fsize"><span class="category-def">Function: </span><span><code class="def-type">unsigned</code> <strong class="def-name">gnutls_cipher_get_tag_size</strong> <code class="def-code-arguments">(gnutls_cipher_algorithm_t <var class="var">algorithm</var>)</code><a class="copiable-link" href="#index-gnutls_005fcipher_005fget_005ftag_005fsize"> &para;</a></span></dt>
<dd><p><var class="var">algorithm</var>: is an encryption algorithm
</p>
<p>This function returns the tag size of an authenticated encryption
algorithm. For non-AEAD algorithms, it returns zero.
</p>
<p><strong class="strong">Returns:</strong> the tag size of the authenticated encryption algorithm.
</p>
<p><strong class="strong">Since:</strong> 3.2.2
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcipher_005finit-1"><span>gnutls_cipher_init<a class="copiable-link" href="#gnutls_005fcipher_005finit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcipher_005finit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcipher_005finit"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_cipher_init</strong> <code class="def-code-arguments">(gnutls_cipher_hd_t * <var class="var">handle</var>, gnutls_cipher_algorithm_t <var class="var">cipher</var>, const gnutls_datum_t * <var class="var">key</var>, const gnutls_datum_t * <var class="var">iv</var>)</code><a class="copiable-link" href="#index-gnutls_005fcipher_005finit"> &para;</a></span></dt>
<dd><p><var class="var">handle</var>: is a <code class="code">gnutls_cipher_hd_t</code>  type
</p>
<p><var class="var">cipher</var>: the encryption algorithm to use
</p>
<p><var class="var">key</var>: the key to be used for encryption/decryption
</p>
<p><var class="var">iv</var>: the IV to use (if not applicable set NULL)
</p>
<p>This function will initialize the  <code class="code">handle</code> context to be usable
for encryption/decryption of data. This will effectively use the
current crypto backend in use by gnutls or the cryptographic
accelerator in use.
</p>
<p><strong class="strong">Returns:</strong> Zero or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 2.10.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcipher_005fset_005fiv-1"><span>gnutls_cipher_set_iv<a class="copiable-link" href="#gnutls_005fcipher_005fset_005fiv-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcipher_005fset_005fiv"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcipher_005fset_005fiv"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_cipher_set_iv</strong> <code class="def-code-arguments">(gnutls_cipher_hd_t <var class="var">handle</var>, void * <var class="var">iv</var>, size_t <var class="var">ivlen</var>)</code><a class="copiable-link" href="#index-gnutls_005fcipher_005fset_005fiv"> &para;</a></span></dt>
<dd><p><var class="var">handle</var>: is a <code class="code">gnutls_cipher_hd_t</code>  type
</p>
<p><var class="var">iv</var>: the IV to set
</p>
<p><var class="var">ivlen</var>: the length of the IV
</p>
<p>This function will set the IV to be used for the next
encryption block.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcipher_005ftag-1"><span>gnutls_cipher_tag<a class="copiable-link" href="#gnutls_005fcipher_005ftag-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcipher_005ftag"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcipher_005ftag"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_cipher_tag</strong> <code class="def-code-arguments">(gnutls_cipher_hd_t <var class="var">handle</var>, void * <var class="var">tag</var>, size_t <var class="var">tag_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fcipher_005ftag"> &para;</a></span></dt>
<dd><p><var class="var">handle</var>: is a <code class="code">gnutls_cipher_hd_t</code>  type
</p>
<p><var class="var">tag</var>: will hold the tag
</p>
<p><var class="var">tag_size</var>: the length of the tag to return
</p>
<p>This function operates on authenticated encryption with
associated data (AEAD) ciphers and will return the
output tag.
</p>
<p><strong class="strong">Returns:</strong> Zero or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcrypto_005fregister_005faead_005fcipher-1"><span>gnutls_crypto_register_aead_cipher<a class="copiable-link" href="#gnutls_005fcrypto_005fregister_005faead_005fcipher-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcrypto_005fregister_005faead_005fcipher"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcrypto_005fregister_005faead_005fcipher-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_crypto_register_aead_cipher</strong> <code class="def-code-arguments">(gnutls_cipher_algorithm_t <var class="var">algorithm</var>, int <var class="var">priority</var>, gnutls_cipher_init_func <var class="var">init</var>, gnutls_cipher_setkey_func <var class="var">setkey</var>, gnutls_cipher_aead_encrypt_func <var class="var">aead_encrypt</var>, gnutls_cipher_aead_decrypt_func <var class="var">aead_decrypt</var>, gnutls_cipher_deinit_func <var class="var">deinit</var>)</code><a class="copiable-link" href="#index-gnutls_005fcrypto_005fregister_005faead_005fcipher-1"> &para;</a></span></dt>
<dd><p><var class="var">algorithm</var>: is the gnutls AEAD cipher identifier
</p>
<p><var class="var">priority</var>: is the priority of the algorithm
</p>
<p><var class="var">init</var>: A function which initializes the cipher
</p>
<p><var class="var">setkey</var>: A function which sets the key of the cipher
</p>
<p><var class="var">aead_encrypt</var>: Perform the AEAD encryption
</p>
<p><var class="var">aead_decrypt</var>: Perform the AEAD decryption
</p>
<p><var class="var">deinit</var>: A function which deinitializes the cipher
</p>
<p>This function will register a cipher algorithm to be used by
gnutls.  Any algorithm registered will override the included
algorithms and by convention kernel implemented algorithms have
priority of 90 and CPU-assisted of 80.  The algorithm with the lowest priority will be
used by gnutls.
</p>
<p>In the case the registered init or setkey functions return <code class="code">GNUTLS_E_NEED_FALLBACK</code> ,
GnuTLS will attempt to use the next in priority registered cipher.
</p>
<p>The functions registered will be used with the new AEAD API introduced in
GnuTLS 3.4.0. Internally GnuTLS uses the new AEAD API.
</p>
<p><strong class="strong">Deprecated:</strong> since 3.7.0 it is no longer possible to override cipher implementation
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcrypto_005fregister_005fcipher-1"><span>gnutls_crypto_register_cipher<a class="copiable-link" href="#gnutls_005fcrypto_005fregister_005fcipher-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcrypto_005fregister_005fcipher"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcrypto_005fregister_005fcipher-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_crypto_register_cipher</strong> <code class="def-code-arguments">(gnutls_cipher_algorithm_t <var class="var">algorithm</var>, int <var class="var">priority</var>, gnutls_cipher_init_func <var class="var">init</var>, gnutls_cipher_setkey_func <var class="var">setkey</var>, gnutls_cipher_setiv_func <var class="var">setiv</var>, gnutls_cipher_encrypt_func <var class="var">encrypt</var>, gnutls_cipher_decrypt_func <var class="var">decrypt</var>, gnutls_cipher_deinit_func <var class="var">deinit</var>)</code><a class="copiable-link" href="#index-gnutls_005fcrypto_005fregister_005fcipher-1"> &para;</a></span></dt>
<dd><p><var class="var">algorithm</var>: is the gnutls algorithm identifier
</p>
<p><var class="var">priority</var>: is the priority of the algorithm
</p>
<p><var class="var">init</var>: A function which initializes the cipher
</p>
<p><var class="var">setkey</var>: A function which sets the key of the cipher
</p>
<p><var class="var">setiv</var>: A function which sets the nonce/IV of the cipher (non-AEAD)
</p>
<p><var class="var">encrypt</var>: A function which performs encryption (non-AEAD)
</p>
<p><var class="var">decrypt</var>: A function which performs decryption (non-AEAD)
</p>
<p><var class="var">deinit</var>: A function which deinitializes the cipher
</p>
<p>This function will register a cipher algorithm to be used by
gnutls.  Any algorithm registered will override the included
algorithms and by convention kernel implemented algorithms have
priority of 90 and CPU-assisted of 80.  The algorithm with the lowest priority will be
used by gnutls.
</p>
<p>In the case the registered init or setkey functions return <code class="code">GNUTLS_E_NEED_FALLBACK</code> ,
GnuTLS will attempt to use the next in priority registered cipher.
</p>
<p>The functions which are marked as non-AEAD they are not required when
registering a cipher to be used with the new AEAD API introduced in
GnuTLS 3.4.0. Internally GnuTLS uses the new AEAD API.
</p>
<p><strong class="strong">Deprecated:</strong> since 3.7.0 it is no longer possible to override cipher implementation
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcrypto_005fregister_005fdigest-1"><span>gnutls_crypto_register_digest<a class="copiable-link" href="#gnutls_005fcrypto_005fregister_005fdigest-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcrypto_005fregister_005fdigest"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcrypto_005fregister_005fdigest-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_crypto_register_digest</strong> <code class="def-code-arguments">(gnutls_digest_algorithm_t <var class="var">algorithm</var>, int <var class="var">priority</var>, gnutls_digest_init_func <var class="var">init</var>, gnutls_digest_hash_func <var class="var">hash</var>, gnutls_digest_output_func <var class="var">output</var>, gnutls_digest_deinit_func <var class="var">deinit</var>, gnutls_digest_fast_func <var class="var">hash_fast</var>)</code><a class="copiable-link" href="#index-gnutls_005fcrypto_005fregister_005fdigest-1"> &para;</a></span></dt>
<dd><p><var class="var">algorithm</var>: is the gnutls digest identifier
</p>
<p><var class="var">priority</var>: is the priority of the algorithm
</p>
<p><var class="var">init</var>: A function which initializes the digest
</p>
<p><var class="var">hash</var>: Perform the hash operation
</p>
<p><var class="var">output</var>: Provide the output of the digest
</p>
<p><var class="var">deinit</var>: A function which deinitializes the digest
</p>
<p><var class="var">hash_fast</var>: Perform the digest operation in one go
</p>
<p>This function will register a digest algorithm to be used by gnutls.
Any algorithm registered will override the included algorithms and
by convention kernel implemented algorithms have priority of 90
and CPU-assisted of 80.
The algorithm with the lowest priority will be used by gnutls.
</p>
<p><strong class="strong">Deprecated:</strong> since 3.7.0 it is no longer possible to override cipher implementation
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcrypto_005fregister_005fmac-1"><span>gnutls_crypto_register_mac<a class="copiable-link" href="#gnutls_005fcrypto_005fregister_005fmac-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcrypto_005fregister_005fmac"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcrypto_005fregister_005fmac-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_crypto_register_mac</strong> <code class="def-code-arguments">(gnutls_mac_algorithm_t <var class="var">algorithm</var>, int <var class="var">priority</var>, gnutls_mac_init_func <var class="var">init</var>, gnutls_mac_setkey_func <var class="var">setkey</var>, gnutls_mac_setnonce_func <var class="var">setnonce</var>, gnutls_mac_hash_func <var class="var">hash</var>, gnutls_mac_output_func <var class="var">output</var>, gnutls_mac_deinit_func <var class="var">deinit</var>, gnutls_mac_fast_func <var class="var">hash_fast</var>)</code><a class="copiable-link" href="#index-gnutls_005fcrypto_005fregister_005fmac-1"> &para;</a></span></dt>
<dd><p><var class="var">algorithm</var>: is the gnutls MAC identifier
</p>
<p><var class="var">priority</var>: is the priority of the algorithm
</p>
<p><var class="var">init</var>: A function which initializes the MAC
</p>
<p><var class="var">setkey</var>: A function which sets the key of the MAC
</p>
<p><var class="var">setnonce</var>: A function which sets the nonce for the mac (may be <code class="code">NULL</code>  for common MAC algorithms)
</p>
<p><var class="var">hash</var>: Perform the hash operation
</p>
<p><var class="var">output</var>: Provide the output of the MAC
</p>
<p><var class="var">deinit</var>: A function which deinitializes the MAC
</p>
<p><var class="var">hash_fast</var>: Perform the MAC operation in one go
</p>
<p>This function will register a MAC algorithm to be used by gnutls.
Any algorithm registered will override the included algorithms and
by convention kernel implemented algorithms have priority of 90
and CPU-assisted of 80.
The algorithm with the lowest priority will be used by gnutls.
</p>
<p><strong class="strong">Deprecated:</strong> since 3.7.0 it is no longer possible to override cipher implementation
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  on success, otherwise a negative error code.
</p>
<p><strong class="strong">Since:</strong> 3.4.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdecode_005fber_005fdigest_005finfo-1"><span>gnutls_decode_ber_digest_info<a class="copiable-link" href="#gnutls_005fdecode_005fber_005fdigest_005finfo-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdecode_005fber_005fdigest_005finfo"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdecode_005fber_005fdigest_005finfo"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_decode_ber_digest_info</strong> <code class="def-code-arguments">(const gnutls_datum_t * <var class="var">info</var>, gnutls_digest_algorithm_t * <var class="var">hash</var>, unsigned char * <var class="var">digest</var>, unsigned int * <var class="var">digest_size</var>)</code><a class="copiable-link" href="#index-gnutls_005fdecode_005fber_005fdigest_005finfo"> &para;</a></span></dt>
<dd><p><var class="var">info</var>: an RSA BER encoded DigestInfo structure
</p>
<p><var class="var">hash</var>: will contain the hash algorithm of the structure
</p>
<p><var class="var">digest</var>: will contain the hash output of the structure
</p>
<p><var class="var">digest_size</var>: will contain the hash size of the structure; initially must hold the maximum size of  <code class="code">digest</code> 
</p>
<p>This function will parse an RSA PKCS<code class="code">1</code>  1.5 DigestInfo structure
and report the hash algorithm used as well as the digest data.
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise
an error code is returned.
</p>
<p><strong class="strong">Since:</strong> 3.5.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdecode_005fgost_005frs_005fvalue-1"><span>gnutls_decode_gost_rs_value<a class="copiable-link" href="#gnutls_005fdecode_005fgost_005frs_005fvalue-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdecode_005fgost_005frs_005fvalue"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdecode_005fgost_005frs_005fvalue"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_decode_gost_rs_value</strong> <code class="def-code-arguments">(const gnutls_datum_t * <var class="var">sig_value</var>, gnutls_datum_t * <var class="var">r</var>, gnutls_datum_t * <var class="var">s</var>)</code><a class="copiable-link" href="#index-gnutls_005fdecode_005fgost_005frs_005fvalue"> &para;</a></span></dt>
<dd><p><var class="var">sig_value</var>: will holds a GOST signature according to RFC 4491 section 2.2.2
</p>
<p><var class="var">r</var>: will contain the r value
</p>
<p><var class="var">s</var>: will contain the s value
</p>
<p>This function will decode the provided  <code class="code">sig_value</code> , into  <code class="code">r</code> and  <code class="code">s</code> elements.
See RFC 4491 section 2.2.2 for the format of signature value.
</p>
<p>The output values may be padded with a zero byte to prevent them
from being interpreted as negative values. The value
should be deallocated using <code class="code">gnutls_free()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise
an error code is returned.
</p>
<p><strong class="strong">Since:</strong> 3.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fdecode_005frs_005fvalue-1"><span>gnutls_decode_rs_value<a class="copiable-link" href="#gnutls_005fdecode_005frs_005fvalue-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fdecode_005frs_005fvalue"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fdecode_005frs_005fvalue"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_decode_rs_value</strong> <code class="def-code-arguments">(const gnutls_datum_t * <var class="var">sig_value</var>, gnutls_datum_t * <var class="var">r</var>, gnutls_datum_t * <var class="var">s</var>)</code><a class="copiable-link" href="#index-gnutls_005fdecode_005frs_005fvalue"> &para;</a></span></dt>
<dd><p><var class="var">sig_value</var>: holds a Dss-Sig-Value DER or BER encoded structure
</p>
<p><var class="var">r</var>: will contain the r value
</p>
<p><var class="var">s</var>: will contain the s value
</p>
<p>This function will decode the provided  <code class="code">sig_value</code> , 
into  <code class="code">r</code> and  <code class="code">s</code> elements. The Dss-Sig-Value is used for DSA and ECDSA
signatures.
</p>
<p>The output values may be padded with a zero byte to prevent them
from being interpreted as negative values. The value
should be deallocated using <code class="code">gnutls_free()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise
an error code is returned.
</p>
<p><strong class="strong">Since:</strong> 3.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fencode_005fber_005fdigest_005finfo-1"><span>gnutls_encode_ber_digest_info<a class="copiable-link" href="#gnutls_005fencode_005fber_005fdigest_005finfo-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fencode_005fber_005fdigest_005finfo"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fencode_005fber_005fdigest_005finfo"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_encode_ber_digest_info</strong> <code class="def-code-arguments">(gnutls_digest_algorithm_t <var class="var">hash</var>, const gnutls_datum_t * <var class="var">digest</var>, gnutls_datum_t * <var class="var">output</var>)</code><a class="copiable-link" href="#index-gnutls_005fencode_005fber_005fdigest_005finfo"> &para;</a></span></dt>
<dd><p><var class="var">hash</var>: the hash algorithm that was used to get the digest
</p>
<p><var class="var">digest</var>: must contain the digest data
</p>
<p><var class="var">output</var>: will contain the allocated DigestInfo BER encoded data
</p>
<p>This function will encode the provided digest data, and its
algorithm into an RSA PKCS<code class="code">1</code>  1.5 DigestInfo structure. 
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise
an error code is returned.
</p>
<p><strong class="strong">Since:</strong> 3.5.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fencode_005fgost_005frs_005fvalue-1"><span>gnutls_encode_gost_rs_value<a class="copiable-link" href="#gnutls_005fencode_005fgost_005frs_005fvalue-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fencode_005fgost_005frs_005fvalue"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fencode_005fgost_005frs_005fvalue"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_encode_gost_rs_value</strong> <code class="def-code-arguments">(gnutls_datum_t * <var class="var">sig_value</var>, const gnutls_datum_t * <var class="var">r</var>, const gnutls_datum_t * <var class="var">s</var>)</code><a class="copiable-link" href="#index-gnutls_005fencode_005fgost_005frs_005fvalue"> &para;</a></span></dt>
<dd><p><var class="var">sig_value</var>: will hold a GOST signature according to RFC 4491 section 2.2.2
</p>
<p><var class="var">r</var>: must contain the r value
</p>
<p><var class="var">s</var>: must contain the s value
</p>
<p>This function will encode the provided r and s values, into binary
representation according to RFC 4491 section 2.2.2, used for GOST R
34.10-2001 (and thus also for GOST R 34.10-2012) signatures.
</p>
<p>The output value should be deallocated using <code class="code">gnutls_free()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise
an error code is returned.
</p>
<p><strong class="strong">Since:</strong> 3.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fencode_005frs_005fvalue-1"><span>gnutls_encode_rs_value<a class="copiable-link" href="#gnutls_005fencode_005frs_005fvalue-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fencode_005frs_005fvalue"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fencode_005frs_005fvalue"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_encode_rs_value</strong> <code class="def-code-arguments">(gnutls_datum_t * <var class="var">sig_value</var>, const gnutls_datum_t * <var class="var">r</var>, const gnutls_datum_t * <var class="var">s</var>)</code><a class="copiable-link" href="#index-gnutls_005fencode_005frs_005fvalue"> &para;</a></span></dt>
<dd><p><var class="var">sig_value</var>: will hold a Dss-Sig-Value DER encoded structure
</p>
<p><var class="var">r</var>: must contain the r value
</p>
<p><var class="var">s</var>: must contain the s value
</p>
<p>This function will encode the provided r and s values, 
into a Dss-Sig-Value structure, used for DSA and ECDSA
signatures.
</p>
<p>The output value should be deallocated using <code class="code">gnutls_free()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise
an error code is returned.
</p>
<p><strong class="strong">Since:</strong> 3.6.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fhash-1"><span>gnutls_hash<a class="copiable-link" href="#gnutls_005fhash-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fhash"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fhash"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_hash</strong> <code class="def-code-arguments">(gnutls_hash_hd_t <var class="var">handle</var>, const void * <var class="var">ptext</var>, size_t <var class="var">ptext_len</var>)</code><a class="copiable-link" href="#index-gnutls_005fhash"> &para;</a></span></dt>
<dd><p><var class="var">handle</var>: is a <code class="code">gnutls_hash_hd_t</code>  type
</p>
<p><var class="var">ptext</var>: the data to hash
</p>
<p><var class="var">ptext_len</var>: the length of data to hash
</p>
<p>This function will hash the given data using the algorithm
specified by the context.
</p>
<p><strong class="strong">Returns:</strong> Zero or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 2.10.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fhash_005fcopy-1"><span>gnutls_hash_copy<a class="copiable-link" href="#gnutls_005fhash_005fcopy-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fhash_005fcopy"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fhash_005fcopy"><span class="category-def">Function: </span><span><code class="def-type">gnutls_hash_hd_t</code> <strong class="def-name">gnutls_hash_copy</strong> <code class="def-code-arguments">(gnutls_hash_hd_t <var class="var">handle</var>)</code><a class="copiable-link" href="#index-gnutls_005fhash_005fcopy"> &para;</a></span></dt>
<dd><p><var class="var">handle</var>: is a <code class="code">gnutls_hash_hd_t</code>  type
</p>
<p>This function will create a copy of Message Digest context, containing all
its current state. Copying contexts for Message Digests registered using
<code class="code">gnutls_crypto_register_digest()</code>  is not supported and will always result in
an error. In addition to that, some of the Message Digest implementations do
not support this operation. Applications should check the return value and
provide a proper fallback.
</p>
<p><strong class="strong">Returns:</strong> new Message Digest context or NULL in case of an error.
</p>
<p><strong class="strong">Since:</strong> 3.6.9
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fhash_005fdeinit-1"><span>gnutls_hash_deinit<a class="copiable-link" href="#gnutls_005fhash_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fhash_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fhash_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_hash_deinit</strong> <code class="def-code-arguments">(gnutls_hash_hd_t <var class="var">handle</var>, void * <var class="var">digest</var>)</code><a class="copiable-link" href="#index-gnutls_005fhash_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">handle</var>: is a <code class="code">gnutls_hash_hd_t</code>  type
</p>
<p><var class="var">digest</var>: is the output value of the hash
</p>
<p>This function will deinitialize all resources occupied by
the given hash context.
</p>
<p><strong class="strong">Since:</strong> 2.10.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fhash_005ffast-1"><span>gnutls_hash_fast<a class="copiable-link" href="#gnutls_005fhash_005ffast-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fhash_005ffast"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fhash_005ffast"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_hash_fast</strong> <code class="def-code-arguments">(gnutls_digest_algorithm_t <var class="var">algorithm</var>, const void * <var class="var">ptext</var>, size_t <var class="var">ptext_len</var>, void * <var class="var">digest</var>)</code><a class="copiable-link" href="#index-gnutls_005fhash_005ffast"> &para;</a></span></dt>
<dd><p><var class="var">algorithm</var>: the hash algorithm to use
</p>
<p><var class="var">ptext</var>: the data to hash
</p>
<p><var class="var">ptext_len</var>: the length of data to hash
</p>
<p><var class="var">digest</var>: is the output value of the hash
</p>
<p>This convenience function will hash the given data and return output
on a single call.
</p>
<p><strong class="strong">Returns:</strong> Zero or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 2.10.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fhash_005fget_005flen-1"><span>gnutls_hash_get_len<a class="copiable-link" href="#gnutls_005fhash_005fget_005flen-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fhash_005fget_005flen"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fhash_005fget_005flen"><span class="category-def">Function: </span><span><code class="def-type">unsigned</code> <strong class="def-name">gnutls_hash_get_len</strong> <code class="def-code-arguments">(gnutls_digest_algorithm_t <var class="var">algorithm</var>)</code><a class="copiable-link" href="#index-gnutls_005fhash_005fget_005flen"> &para;</a></span></dt>
<dd><p><var class="var">algorithm</var>: the hash algorithm to use
</p>
<p>This function will return the length of the output data
of the given hash algorithm.
</p>
<p><strong class="strong">Returns:</strong> The length or zero on error.
</p>
<p><strong class="strong">Since:</strong> 2.10.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fhash_005finit-1"><span>gnutls_hash_init<a class="copiable-link" href="#gnutls_005fhash_005finit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fhash_005finit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fhash_005finit"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_hash_init</strong> <code class="def-code-arguments">(gnutls_hash_hd_t * <var class="var">dig</var>, gnutls_digest_algorithm_t <var class="var">algorithm</var>)</code><a class="copiable-link" href="#index-gnutls_005fhash_005finit"> &para;</a></span></dt>
<dd><p><var class="var">dig</var>: is a <code class="code">gnutls_hash_hd_t</code>  type
</p>
<p><var class="var">algorithm</var>: the hash algorithm to use
</p>
<p>This function will initialize an context that can be used to
produce a Message Digest of data.  This will effectively use the
current crypto backend in use by gnutls or the cryptographic
accelerator in use.
</p>
<p><strong class="strong">Returns:</strong> Zero or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 2.10.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fhash_005foutput-1"><span>gnutls_hash_output<a class="copiable-link" href="#gnutls_005fhash_005foutput-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fhash_005foutput"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fhash_005foutput"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_hash_output</strong> <code class="def-code-arguments">(gnutls_hash_hd_t <var class="var">handle</var>, void * <var class="var">digest</var>)</code><a class="copiable-link" href="#index-gnutls_005fhash_005foutput"> &para;</a></span></dt>
<dd><p><var class="var">handle</var>: is a <code class="code">gnutls_hash_hd_t</code>  type
</p>
<p><var class="var">digest</var>: is the output value of the hash
</p>
<p>This function will output the current hash value and reset the
state of the hash. If  <code class="code">digest</code> is <code class="code">NULL</code> , it only resets the state of
the hash.
</p>
<p><strong class="strong">Since:</strong> 2.10.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fhash_005fsqueeze-1"><span>gnutls_hash_squeeze<a class="copiable-link" href="#gnutls_005fhash_005fsqueeze-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fhash_005fsqueeze"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fhash_005fsqueeze"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_hash_squeeze</strong> <code class="def-code-arguments">(gnutls_hash_hd_t <var class="var">handle</var>, void * <var class="var">output</var>, size_t <var class="var">length</var>)</code><a class="copiable-link" href="#index-gnutls_005fhash_005fsqueeze"> &para;</a></span></dt>
<dd><p><var class="var">handle</var>: a <code class="code">gnutls_hash_hd_t</code> 
</p>
<p><var class="var">output</var>: destination to store the output; must be equal to or larger than  <code class="code">length</code> 
</p>
<p><var class="var">length</var>: length of  <code class="code">output</code> 
</p>
<p>This function will extract digest output of  <code class="code">length</code> bytes. The  <code class="code">handle</code> must
be initialized with <code class="code">gnutls_hash_init()</code>  as an extended output function (XOF),
such as <code class="code">GNUTLS_DIG_SHAKE_128</code>  or <code class="code">GNUTLS_DIG_SHAKE_256</code> .
</p>
<p>This function can be called multiple times. To reset the state of  <code class="code">handle</code> ,
call <code class="code">gnutls_hash_deinit()</code>  with <code class="code">NULL</code>  as the digest argument.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_SUCCESS</code>  (0) on success; negative error code otherwise.
</p>
<p><strong class="strong">Since:</strong> 3.8.6
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fhkdf_005fexpand-1"><span>gnutls_hkdf_expand<a class="copiable-link" href="#gnutls_005fhkdf_005fexpand-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fhkdf_005fexpand"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fhkdf_005fexpand"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_hkdf_expand</strong> <code class="def-code-arguments">(gnutls_mac_algorithm_t <var class="var">mac</var>, const gnutls_datum_t * <var class="var">key</var>, const gnutls_datum_t * <var class="var">info</var>, void * <var class="var">output</var>, size_t <var class="var">length</var>)</code><a class="copiable-link" href="#index-gnutls_005fhkdf_005fexpand"> &para;</a></span></dt>
<dd><p><var class="var">mac</var>: the mac algorithm used internally
</p>
<p><var class="var">key</var>: the pseudorandom key created with HKDF-Extract
</p>
<p><var class="var">info</var>: the optional informational data
</p>
<p><var class="var">output</var>: the output value of the expand operation
</p>
<p><var class="var">length</var>: the desired length of the output key
</p>
<p>This function will derive a variable length keying material from
the pseudorandom key using the HKDF-Expand function as defined in
RFC 5869.
</p>
<p><strong class="strong">Returns:</strong> Zero or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 3.6.13
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fhkdf_005fextract-1"><span>gnutls_hkdf_extract<a class="copiable-link" href="#gnutls_005fhkdf_005fextract-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fhkdf_005fextract"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fhkdf_005fextract"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_hkdf_extract</strong> <code class="def-code-arguments">(gnutls_mac_algorithm_t <var class="var">mac</var>, const gnutls_datum_t * <var class="var">key</var>, const gnutls_datum_t * <var class="var">salt</var>, void * <var class="var">output</var>)</code><a class="copiable-link" href="#index-gnutls_005fhkdf_005fextract"> &para;</a></span></dt>
<dd><p><var class="var">mac</var>: the mac algorithm used internally
</p>
<p><var class="var">key</var>: the initial keying material
</p>
<p><var class="var">salt</var>: the optional salt
</p>
<p><var class="var">output</var>: the output value of the extract operation
</p>
<p>This function will derive a fixed-size key using the HKDF-Extract
function as defined in RFC 5869.
</p>
<p><strong class="strong">Returns:</strong> Zero or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 3.6.13
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fhmac-1"><span>gnutls_hmac<a class="copiable-link" href="#gnutls_005fhmac-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fhmac"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fhmac"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_hmac</strong> <code class="def-code-arguments">(gnutls_hmac_hd_t <var class="var">handle</var>, const void * <var class="var">ptext</var>, size_t <var class="var">ptext_len</var>)</code><a class="copiable-link" href="#index-gnutls_005fhmac"> &para;</a></span></dt>
<dd><p><var class="var">handle</var>: is a <code class="code">gnutls_hmac_hd_t</code>  type
</p>
<p><var class="var">ptext</var>: the data to hash
</p>
<p><var class="var">ptext_len</var>: the length of data to hash
</p>
<p>This function will hash the given data using the algorithm
specified by the context.
</p>
<p><strong class="strong">Returns:</strong> Zero or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 2.10.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fhmac_005fcopy-1"><span>gnutls_hmac_copy<a class="copiable-link" href="#gnutls_005fhmac_005fcopy-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fhmac_005fcopy"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fhmac_005fcopy"><span class="category-def">Function: </span><span><code class="def-type">gnutls_hmac_hd_t</code> <strong class="def-name">gnutls_hmac_copy</strong> <code class="def-code-arguments">(gnutls_hmac_hd_t <var class="var">handle</var>)</code><a class="copiable-link" href="#index-gnutls_005fhmac_005fcopy"> &para;</a></span></dt>
<dd><p><var class="var">handle</var>: is a <code class="code">gnutls_hmac_hd_t</code>  type
</p>
<p>This function will create a copy of MAC context, containing all its current
state. Copying contexts for MACs registered using
<code class="code">gnutls_crypto_register_mac()</code>  is not supported and will always result in an
error. In addition to that, some of the MAC implementations do not support
this operation. Applications should check the return value and provide a
proper fallback.
</p>
<p><strong class="strong">Returns:</strong> new MAC context or NULL in case of an error.
</p>
<p><strong class="strong">Since:</strong> 3.6.9
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fhmac_005fdeinit-1"><span>gnutls_hmac_deinit<a class="copiable-link" href="#gnutls_005fhmac_005fdeinit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fhmac_005fdeinit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fhmac_005fdeinit"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_hmac_deinit</strong> <code class="def-code-arguments">(gnutls_hmac_hd_t <var class="var">handle</var>, void * <var class="var">digest</var>)</code><a class="copiable-link" href="#index-gnutls_005fhmac_005fdeinit"> &para;</a></span></dt>
<dd><p><var class="var">handle</var>: is a <code class="code">gnutls_hmac_hd_t</code>  type
</p>
<p><var class="var">digest</var>: is the output value of the MAC
</p>
<p>This function will deinitialize all resources occupied by
the given hmac context.
</p>
<p><strong class="strong">Since:</strong> 2.10.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fhmac_005ffast-1"><span>gnutls_hmac_fast<a class="copiable-link" href="#gnutls_005fhmac_005ffast-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fhmac_005ffast"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fhmac_005ffast"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_hmac_fast</strong> <code class="def-code-arguments">(gnutls_mac_algorithm_t <var class="var">algorithm</var>, const void * <var class="var">key</var>, size_t <var class="var">keylen</var>, const void * <var class="var">ptext</var>, size_t <var class="var">ptext_len</var>, void * <var class="var">digest</var>)</code><a class="copiable-link" href="#index-gnutls_005fhmac_005ffast"> &para;</a></span></dt>
<dd><p><var class="var">algorithm</var>: the hash algorithm to use
</p>
<p><var class="var">key</var>: the key to use
</p>
<p><var class="var">keylen</var>: the length of the key
</p>
<p><var class="var">ptext</var>: the data to hash
</p>
<p><var class="var">ptext_len</var>: the length of data to hash
</p>
<p><var class="var">digest</var>: is the output value of the hash
</p>
<p>This convenience function will hash the given data and return output
on a single call. Note, this call will not work for MAC algorithms
that require nonce (like UMAC or GMAC).
</p>
<p><strong class="strong">Returns:</strong> Zero or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 2.10.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fhmac_005fget_005fkey_005fsize-1"><span>gnutls_hmac_get_key_size<a class="copiable-link" href="#gnutls_005fhmac_005fget_005fkey_005fsize-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fhmac_005fget_005fkey_005fsize"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fhmac_005fget_005fkey_005fsize"><span class="category-def">Function: </span><span><code class="def-type">unsigned</code> <strong class="def-name">gnutls_hmac_get_key_size</strong> <code class="def-code-arguments">(gnutls_mac_algorithm_t <var class="var">algorithm</var>)</code><a class="copiable-link" href="#index-gnutls_005fhmac_005fget_005fkey_005fsize"> &para;</a></span></dt>
<dd><p><var class="var">algorithm</var>: the mac algorithm to use
</p>
<p>This function will return the size of the key to be used with this
algorithm. On the algorithms which may accept arbitrary key sizes,
the returned size is the MAC key size used in the TLS protocol.
</p>
<p><strong class="strong">Returns:</strong> The key size or zero on error.
</p>
<p><strong class="strong">Since:</strong> 3.6.12
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fhmac_005fget_005flen-1"><span>gnutls_hmac_get_len<a class="copiable-link" href="#gnutls_005fhmac_005fget_005flen-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fhmac_005fget_005flen"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fhmac_005fget_005flen"><span class="category-def">Function: </span><span><code class="def-type">unsigned</code> <strong class="def-name">gnutls_hmac_get_len</strong> <code class="def-code-arguments">(gnutls_mac_algorithm_t <var class="var">algorithm</var>)</code><a class="copiable-link" href="#index-gnutls_005fhmac_005fget_005flen"> &para;</a></span></dt>
<dd><p><var class="var">algorithm</var>: the hmac algorithm to use
</p>
<p>This function will return the length of the output data
of the given hmac algorithm.
</p>
<p><strong class="strong">Returns:</strong> The length or zero on error.
</p>
<p><strong class="strong">Since:</strong> 2.10.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fhmac_005finit-1"><span>gnutls_hmac_init<a class="copiable-link" href="#gnutls_005fhmac_005finit-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fhmac_005finit"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fhmac_005finit"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_hmac_init</strong> <code class="def-code-arguments">(gnutls_hmac_hd_t * <var class="var">dig</var>, gnutls_mac_algorithm_t <var class="var">algorithm</var>, const void * <var class="var">key</var>, size_t <var class="var">keylen</var>)</code><a class="copiable-link" href="#index-gnutls_005fhmac_005finit"> &para;</a></span></dt>
<dd><p><var class="var">dig</var>: is a <code class="code">gnutls_hmac_hd_t</code>  type
</p>
<p><var class="var">algorithm</var>: the HMAC algorithm to use
</p>
<p><var class="var">key</var>: the key to be used for encryption
</p>
<p><var class="var">keylen</var>: the length of the key
</p>
<p>This function will initialize an context that can be used to
produce a Message Authentication Code (MAC) of data.  This will
effectively use the current crypto backend in use by gnutls or the
cryptographic accelerator in use.
</p>
<p>Note that despite the name of this function, it can be used
for other MAC algorithms than HMAC.
</p>
<p><strong class="strong">Returns:</strong> Zero or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 2.10.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fhmac_005foutput-1"><span>gnutls_hmac_output<a class="copiable-link" href="#gnutls_005fhmac_005foutput-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fhmac_005foutput"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fhmac_005foutput"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_hmac_output</strong> <code class="def-code-arguments">(gnutls_hmac_hd_t <var class="var">handle</var>, void * <var class="var">digest</var>)</code><a class="copiable-link" href="#index-gnutls_005fhmac_005foutput"> &para;</a></span></dt>
<dd><p><var class="var">handle</var>: is a <code class="code">gnutls_hmac_hd_t</code>  type
</p>
<p><var class="var">digest</var>: is the output value of the MAC
</p>
<p>This function will output the current MAC value
and reset the state of the MAC.
</p>
<p><strong class="strong">Since:</strong> 2.10.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fhmac_005fset_005fnonce-1"><span>gnutls_hmac_set_nonce<a class="copiable-link" href="#gnutls_005fhmac_005fset_005fnonce-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fhmac_005fset_005fnonce"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fhmac_005fset_005fnonce"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_hmac_set_nonce</strong> <code class="def-code-arguments">(gnutls_hmac_hd_t <var class="var">handle</var>, const void * <var class="var">nonce</var>, size_t <var class="var">nonce_len</var>)</code><a class="copiable-link" href="#index-gnutls_005fhmac_005fset_005fnonce"> &para;</a></span></dt>
<dd><p><var class="var">handle</var>: is a <code class="code">gnutls_hmac_hd_t</code>  type
</p>
<p><var class="var">nonce</var>: the data to set as nonce
</p>
<p><var class="var">nonce_len</var>: the length of data
</p>
<p>This function will set the nonce in the MAC algorithm.
</p>
<p><strong class="strong">Since:</strong> 3.2.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fmac_005fget_005fnonce_005fsize-1"><span>gnutls_mac_get_nonce_size<a class="copiable-link" href="#gnutls_005fmac_005fget_005fnonce_005fsize-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fmac_005fget_005fnonce_005fsize"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fmac_005fget_005fnonce_005fsize"><span class="category-def">Function: </span><span><code class="def-type">size_t</code> <strong class="def-name">gnutls_mac_get_nonce_size</strong> <code class="def-code-arguments">(gnutls_mac_algorithm_t <var class="var">algorithm</var>)</code><a class="copiable-link" href="#index-gnutls_005fmac_005fget_005fnonce_005fsize"> &para;</a></span></dt>
<dd><p><var class="var">algorithm</var>: is an encryption algorithm
</p>
<p>Returns the size of the nonce used by the MAC in TLS.
</p>
<p><strong class="strong">Returns:</strong> length (in bytes) of the given MAC nonce size, or 0.
</p>
<p><strong class="strong">Since:</strong> 3.2.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpbkdf2-1"><span>gnutls_pbkdf2<a class="copiable-link" href="#gnutls_005fpbkdf2-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpbkdf2"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpbkdf2"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_pbkdf2</strong> <code class="def-code-arguments">(gnutls_mac_algorithm_t <var class="var">mac</var>, const gnutls_datum_t * <var class="var">key</var>, const gnutls_datum_t * <var class="var">salt</var>, unsigned <var class="var">iter_count</var>, void * <var class="var">output</var>, size_t <var class="var">length</var>)</code><a class="copiable-link" href="#index-gnutls_005fpbkdf2"> &para;</a></span></dt>
<dd><p><var class="var">mac</var>: the mac algorithm used internally
</p>
<p><var class="var">key</var>: the initial keying material
</p>
<p><var class="var">salt</var>: the salt
</p>
<p><var class="var">iter_count</var>: the iteration count
</p>
<p><var class="var">output</var>: the output value
</p>
<p><var class="var">length</var>: the desired length of the output key
</p>
<p>This function will derive a variable length keying material from
a password according to PKCS <code class="code">5</code>  PBKDF2.
</p>
<p><strong class="strong">Returns:</strong> Zero or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 3.6.13
</p></dd></dl>

<h4 class="subheading" id="gnutls_005frnd-1"><span>gnutls_rnd<a class="copiable-link" href="#gnutls_005frnd-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005frnd"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frnd-1"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_rnd</strong> <code class="def-code-arguments">(gnutls_rnd_level_t <var class="var">level</var>, void * <var class="var">data</var>, size_t <var class="var">len</var>)</code><a class="copiable-link" href="#index-gnutls_005frnd-1"> &para;</a></span></dt>
<dd><p><var class="var">level</var>: a security level
</p>
<p><var class="var">data</var>: place to store random bytes
</p>
<p><var class="var">len</var>: The requested size
</p>
<p>This function will generate random data and store it to output
buffer. The value of  <code class="code">level</code> should be one of <code class="code">GNUTLS_RND_NONCE</code> ,
<code class="code">GNUTLS_RND_RANDOM</code>  and <code class="code">GNUTLS_RND_KEY</code> . See the manual and
<code class="code">gnutls_rnd_level_t</code>  for detailed information.
</p>
<p>This function is thread-safe and also fork-safe.
</p>
<p><strong class="strong">Returns:</strong> Zero on success, or a negative error code on error.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005frnd_005frefresh-1"><span>gnutls_rnd_refresh<a class="copiable-link" href="#gnutls_005frnd_005frefresh-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005frnd_005frefresh"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005frnd_005frefresh"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_rnd_refresh</strong> <code class="def-code-arguments">( <var class="var">void</var>)</code><a class="copiable-link" href="#index-gnutls_005frnd_005frefresh"> &para;</a></span></dt>
<dd>
<p>This function refreshes the random generator state.
That is the current precise time, CPU usage, and
other values are input into its state.
</p>
<p>On a slower rate input from /dev/urandom is mixed too.
</p>
<p><strong class="strong">Since:</strong> 3.1.7
</p></dd></dl>


<hr>
</div>
<div class="section-level-extent" id="Compatibility-API">
<div class="nav-panel">
<p>
Previous: <a href="#Cryptographic-API" accesskey="p" rel="prev">Cryptographic API</a>, Up: <a href="#API-reference" accesskey="u" rel="up">API reference</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="Compatibility-API-1"><span>E.13 Compatibility API<a class="copiable-link" href="#Compatibility-API-1"> &para;</a></span></h3>

<p>The following functions are carried over from old GnuTLS released. They might be removed at a later version.
Their prototypes lie in <samp class="file">gnutls/compat.h</samp>.
</p>

<h4 class="subheading" id="gnutls_005fcompression_005fget-1"><span>gnutls_compression_get<a class="copiable-link" href="#gnutls_005fcompression_005fget-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcompression_005fget"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcompression_005fget"><span class="category-def">Function: </span><span><code class="def-type">gnutls_compression_method_t</code> <strong class="def-name">gnutls_compression_get</strong> <code class="def-code-arguments">(gnutls_session_t <var class="var">session</var>)</code><a class="copiable-link" href="#index-gnutls_005fcompression_005fget"> &para;</a></span></dt>
<dd><p><var class="var">session</var>: is a <code class="code">gnutls_session_t</code>  type.
</p>
<p>Get the currently used compression algorithm.
</p>
<p><strong class="strong">Returns:</strong> the currently used compression method, a
<code class="code">gnutls_compression_method_t</code>  value.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcompression_005fget_005fid-1"><span>gnutls_compression_get_id<a class="copiable-link" href="#gnutls_005fcompression_005fget_005fid-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcompression_005fget_005fid"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcompression_005fget_005fid"><span class="category-def">Function: </span><span><code class="def-type">gnutls_compression_method_t</code> <strong class="def-name">gnutls_compression_get_id</strong> <code class="def-code-arguments">(const char * <var class="var">name</var>)</code><a class="copiable-link" href="#index-gnutls_005fcompression_005fget_005fid"> &para;</a></span></dt>
<dd><p><var class="var">name</var>: is a compression method name
</p>
<p>The names are compared in a case insensitive way.
</p>
<p><strong class="strong">Returns:</strong> an id of the specified in a string compression method, or
<code class="code">GNUTLS_COMP_UNKNOWN</code>  on error.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcompression_005fget_005fname-1"><span>gnutls_compression_get_name<a class="copiable-link" href="#gnutls_005fcompression_005fget_005fname-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcompression_005fget_005fname"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcompression_005fget_005fname"><span class="category-def">Function: </span><span><code class="def-type">const char *</code> <strong class="def-name">gnutls_compression_get_name</strong> <code class="def-code-arguments">(gnutls_compression_method_t <var class="var">algorithm</var>)</code><a class="copiable-link" href="#index-gnutls_005fcompression_005fget_005fname"> &para;</a></span></dt>
<dd><p><var class="var">algorithm</var>: is a Compression algorithm
</p>
<p>Convert a <code class="code">gnutls_compression_method_t</code>  value to a string.
</p>
<p><strong class="strong">Returns:</strong> a pointer to a string that contains the name of the
specified compression algorithm, or <code class="code">NULL</code> .
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fcompression_005flist-1"><span>gnutls_compression_list<a class="copiable-link" href="#gnutls_005fcompression_005flist-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fcompression_005flist"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fcompression_005flist"><span class="category-def">Function: </span><span><code class="def-type">const gnutls_compression_method_t *</code> <strong class="def-name">gnutls_compression_list</strong> <code class="def-code-arguments">( <var class="var">void</var>)</code><a class="copiable-link" href="#index-gnutls_005fcompression_005flist"> &para;</a></span></dt>
<dd>
<p>Get a list of compression methods.
</p>
<p><strong class="strong">Returns:</strong> a zero-terminated list of <code class="code">gnutls_compression_method_t</code> 
integers indicating the available compression methods.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fglobal_005fset_005fmem_005ffunctions-1"><span>gnutls_global_set_mem_functions<a class="copiable-link" href="#gnutls_005fglobal_005fset_005fmem_005ffunctions-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fglobal_005fset_005fmem_005ffunctions"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fglobal_005fset_005fmem_005ffunctions"><span class="category-def">Function: </span><span><code class="def-type">void</code> <strong class="def-name">gnutls_global_set_mem_functions</strong> <code class="def-code-arguments">(gnutls_alloc_function <var class="var">alloc_func</var>, gnutls_alloc_function <var class="var">secure_alloc_func</var>, gnutls_is_secure_function <var class="var">is_secure_func</var>, gnutls_realloc_function <var class="var">realloc_func</var>, gnutls_free_function <var class="var">free_func</var>)</code><a class="copiable-link" href="#index-gnutls_005fglobal_005fset_005fmem_005ffunctions"> &para;</a></span></dt>
<dd><p><var class="var">alloc_func</var>: it&rsquo;s the default memory allocation function. Like <code class="code">malloc()</code> .
</p>
<p><var class="var">secure_alloc_func</var>: This is the memory allocation function that will be used for sensitive data.
</p>
<p><var class="var">is_secure_func</var>: a function that returns 0 if the memory given is not secure. May be NULL.
</p>
<p><var class="var">realloc_func</var>: A realloc function
</p>
<p><var class="var">free_func</var>: The function that frees allocated data. Must accept a NULL pointer.
</p>

<p><strong class="strong">Deprecated:</strong> since 3.3.0 it is no longer possible to replace the internally used 
memory allocation functions
</p>
<p>This is the function where you set the memory allocation functions
gnutls is going to use. By default the libc&rsquo;s allocation functions
(<code class="code">malloc()</code> , <code class="code">free()</code> ), are used by gnutls, to allocate both sensitive
and not sensitive data.  This function is provided to set the
memory allocation functions to something other than the defaults
</p>
<p>This function must be called before <code class="code">gnutls_global_init()</code>  is called.
This function is not thread safe.
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fopenpgp_005fprivkey_005fsign_005fhash-1"><span>gnutls_openpgp_privkey_sign_hash<a class="copiable-link" href="#gnutls_005fopenpgp_005fprivkey_005fsign_005fhash-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fopenpgp_005fprivkey_005fsign_005fhash"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fopenpgp_005fprivkey_005fsign_005fhash"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_openpgp_privkey_sign_hash</strong> <code class="def-code-arguments">(gnutls_openpgp_privkey_t <var class="var">key</var>, const gnutls_datum_t * <var class="var">hash</var>, gnutls_datum_t * <var class="var">signature</var>)</code><a class="copiable-link" href="#index-gnutls_005fopenpgp_005fprivkey_005fsign_005fhash"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: Holds the key
</p>
<p><var class="var">hash</var>: holds the data to be signed
</p>
<p><var class="var">signature</var>: will contain newly allocated signature
</p>
<p>This function is no-op.
</p>
<p><strong class="strong">Returns:</strong> <code class="code">GNUTLS_E_UNIMPLEMENTED_FEATURE</code> .
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fpriority_005fcompression_005flist-1"><span>gnutls_priority_compression_list<a class="copiable-link" href="#gnutls_005fpriority_005fcompression_005flist-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fpriority_005fcompression_005flist"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fpriority_005fcompression_005flist"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_priority_compression_list</strong> <code class="def-code-arguments">(gnutls_priority_t <var class="var">pcache</var>, const unsigned int ** <var class="var">list</var>)</code><a class="copiable-link" href="#index-gnutls_005fpriority_005fcompression_005flist"> &para;</a></span></dt>
<dd><p><var class="var">pcache</var>: is a <code class="code">gnutls_priority_t</code>  type.
</p>
<p><var class="var">list</var>: will point to an integer list
</p>
<p>Get a list of available compression method in the priority
structure.
</p>
<p><strong class="strong">Returns:</strong> the number of methods, or an error code.
</p>
<p><strong class="strong">Since:</strong> 3.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fcrt_005fget_005fpreferred_005fhash_005falgorithm-1"><span>gnutls_x509_crt_get_preferred_hash_algorithm<a class="copiable-link" href="#gnutls_005fx509_005fcrt_005fget_005fpreferred_005fhash_005falgorithm-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fcrt_005fget_005fpreferred_005fhash_005falgorithm"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fcrt_005fget_005fpreferred_005fhash_005falgorithm"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_crt_get_preferred_hash_algorithm</strong> <code class="def-code-arguments">(gnutls_x509_crt_t <var class="var">crt</var>, gnutls_digest_algorithm_t * <var class="var">hash</var>, unsigned int * <var class="var">mand</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fcrt_005fget_005fpreferred_005fhash_005falgorithm"> &para;</a></span></dt>
<dd><p><var class="var">crt</var>: Holds the certificate
</p>
<p><var class="var">hash</var>: The result of the call with the hash algorithm used for signature
</p>
<p><var class="var">mand</var>: If non-zero it means that the algorithm MUST use this hash. May be <code class="code">NULL</code> .
</p>
<p>This function will read the certificate and return the appropriate digest
algorithm to use for signing with this certificate. Some certificates (i.e.
DSA might not be able to sign without the preferred algorithm).
</p>
<p><strong class="strong">Deprecated:</strong> Please use <code class="code">gnutls_pubkey_get_preferred_hash_algorithm()</code> .
</p>
<p><strong class="strong">Returns:</strong> the 0 if the hash algorithm is found. A negative error code is
returned on error.
</p>
<p><strong class="strong">Since:</strong> 2.12.0
</p></dd></dl>

<h4 class="subheading" id="gnutls_005fx509_005fprivkey_005fsign_005fhash-1"><span>gnutls_x509_privkey_sign_hash<a class="copiable-link" href="#gnutls_005fx509_005fprivkey_005fsign_005fhash-1"> &para;</a></span></h4>
<a class="anchor" id="gnutls_005fx509_005fprivkey_005fsign_005fhash"></a><dl class="first-deftypefn first-deftypefun-alias-first-deftypefn def-block">
<dt class="deftypefn deftypefun-alias-deftypefn def-line" id="index-gnutls_005fx509_005fprivkey_005fsign_005fhash"><span class="category-def">Function: </span><span><code class="def-type">int</code> <strong class="def-name">gnutls_x509_privkey_sign_hash</strong> <code class="def-code-arguments">(gnutls_x509_privkey_t <var class="var">key</var>, const gnutls_datum_t * <var class="var">hash</var>, gnutls_datum_t * <var class="var">signature</var>)</code><a class="copiable-link" href="#index-gnutls_005fx509_005fprivkey_005fsign_005fhash"> &para;</a></span></dt>
<dd><p><var class="var">key</var>: a key
</p>
<p><var class="var">hash</var>: holds the data to be signed
</p>
<p><var class="var">signature</var>: will contain newly allocated signature
</p>
<p>This function will sign the given hash using the private key. Do not
use this function directly unless you know what it is. Typical signing
requires the data to be hashed and stored in special formats 
(e.g. BER Digest-Info for RSA).
</p>
<p>This API is provided only for backwards compatibility, and thus
restricted to RSA, DSA and ECDSA key types. For other key types please
use <code class="code">gnutls_privkey_sign_hash()</code>  and <code class="code">gnutls_privkey_sign_data()</code> .
</p>
<p><strong class="strong">Returns:</strong> On success, <code class="code">GNUTLS_E_SUCCESS</code>  (0) is returned, otherwise a
negative error value.
</p>
<p>Deprecated in: 2.12.0
</p></dd></dl>


<hr>
</div>
</div>
<div class="appendix-level-extent" id="Copying-Information">
<div class="nav-panel">
<p>
Next: <a href="#Additional-Features" accesskey="n" rel="next">Additional Features</a>, Previous: <a href="#API-reference" accesskey="p" rel="prev">API reference</a>, Up: <a href="#Top" accesskey="u" rel="up">GnuTLS</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h2 class="appendix" id="Copying-Information-1"><span>Appendix F Copying Information<a class="copiable-link" href="#Copying-Information-1"> &para;</a></span></h2>
<a class="index-entry-id" id="index-FDL_002c-GNU-Free-Documentation-License"></a>

<h3 class="heading" id="GNU-Free-Documentation-License"><span>GNU Free Documentation License<a class="copiable-link" href="#GNU-Free-Documentation-License"> &para;</a></span></h3>

<div class="center">Version 1.3, 3 November 2008
</div>

<div class="display">
<pre class="display-preformatted">Copyright &copy; 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc.
<a class="uref" href="https://fsf.org/">https://fsf.org/</a>

Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.
</pre></div>

<ol class="enumerate" start="0">
<li> PREAMBLE

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<p>You may combine the Document with other documents released under this
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<p>You may make a collection consisting of the Document and other documents
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<p>If a section in the Document is Entitled &ldquo;Acknowledgements&rdquo;,
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<p>You may not copy, modify, sublicense, or distribute the Document
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<p>&ldquo;Massive Multiauthor Collaboration Site&rdquo; (or &ldquo;MMC Site&rdquo;) means any
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<p>&ldquo;CC-BY-SA&rdquo; means the Creative Commons Attribution-Share Alike 3.0
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<p>&ldquo;Incorporate&rdquo; means to publish or republish a Document, in whole or
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<p>An MMC is &ldquo;eligible for relicensing&rdquo; if it is licensed under this
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<p>The operator of an MMC Site may republish an MMC contained in the site
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</li></ol>

<h3 class="heading" id="ADDENDUM_003a-How-to-use-this-License-for-your-documents"><span>ADDENDUM: How to use this License for your documents<a class="copiable-link" href="#ADDENDUM_003a-How-to-use-this-License-for-your-documents"> &para;</a></span></h3>

<p>To use this License in a document you have written, include a copy of
the License in the document and put the following copyright and
license notices just after the title page:
</p>
<div class="example smallexample">
<div class="group"><pre class="example-preformatted">  Copyright (C)  <var class="var">year</var>  <var class="var">your name</var>.
  Permission is granted to copy, distribute and/or modify this document
  under the terms of the GNU Free Documentation License, Version 1.3
  or any later version published by the Free Software Foundation;
  with no Invariant Sections, no Front-Cover Texts, and no Back-Cover
  Texts.  A copy of the license is included in the section entitled ``GNU
  Free Documentation License''.
</pre></div></div>

<p>If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts,
replace the &ldquo;with&hellip;Texts.&rdquo; line with this:
</p>
<div class="example smallexample">
<div class="group"><pre class="example-preformatted">    with the Invariant Sections being <var class="var">list their titles</var>, with
    the Front-Cover Texts being <var class="var">list</var>, and with the Back-Cover Texts
    being <var class="var">list</var>.
</pre></div></div>

<p>If you have Invariant Sections without Cover Texts, or some other
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<p>If your document contains nontrivial examples of program code, we
recommend releasing these examples in parallel under your choice of
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to permit their use in free software.
</p>


<hr>
</div>
<div class="appendix-level-extent" id="Additional-Features">
<div class="nav-panel">
<p>
Next: <a href="#Bibliography" accesskey="n" rel="next">Bibliography</a>, Previous: <a href="#Copying-Information" accesskey="p" rel="prev">Copying Information</a>, Up: <a href="#Top" accesskey="u" rel="up">GnuTLS</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h2 class="appendix" id="Additional-Features-1"><span>Appendix G Additional Features<a class="copiable-link" href="#Additional-Features-1"> &para;</a></span></h2>


<ul class="mini-toc">
<li><a href="#kTLS-_0028Kernel-TLS_0029" accesskey="1">kTLS (Kernel TLS)</a></li>
</ul>
<hr>
<div class="section-level-extent" id="kTLS-_0028Kernel-TLS_0029">
<div class="nav-panel">
<p>
Up: <a href="#Additional-Features" accesskey="u" rel="up">Additional Features</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h3 class="section" id="kTLS-_0028Kernel-TLS_0029-1"><span>G.1 kTLS (Kernel TLS)<a class="copiable-link" href="#kTLS-_0028Kernel-TLS_0029-1"> &para;</a></span></h3>
<a class="index-entry-id" id="index-kTLS-_0028Kernel-TLS_0029"></a>
<p>kTLS (Kernel TLS) is a Linux kernel feature that offloads TLS encryption and decryption operations to the kernel space, improving performance and reducing CPU overhead. It allows applications to leverage zero-copy data transmission, reducing context switches between user space and kernel space.
</p>
<p>The following table shows how to enable kTLS support on Linux and FreeBSD systems.
</p><div class="float" id="tab_003aktls_005fsupport">
<table class="multitable">
<thead><tr><th width="40%">Description</th><th width="30%">Linux</th><th width="30%">FreeBSD</th></tr></thead>
<tbody><tr><td width="40%">Load kernel module</td><td width="30%"><code class="code">modprobe tls</code></td><td width="30%"><code class="code">kldload tls</code></td></tr>
<tr><td width="40%">Check if module is loaded</td><td width="30%"><code class="code">lsmod | grep tls</code></td><td width="30%"><code class="code">kldstat | grep tls</code></td></tr>
<tr><td width="40%">kTLS rekey support</td><td width="30%">v6.14</td><td width="30%">not yet supported</td></tr>
</tbody>
</table>
<div class="caption"><p><strong class="strong">Table G.1: </strong>kTLS system enable</p></div></div>
<p>To enable ktls in GnuTLS <a class="ref" href="#Enabling-kTLS">Enabling kTLS</a>.
</p>

<hr>
</div>
</div>
<div class="unnumbered-level-extent" id="Bibliography">
<div class="nav-panel">
<p>
Next: <a href="#Function-and-Data-Index" accesskey="n" rel="next">Function and Data Index</a>, Previous: <a href="#Additional-Features" accesskey="p" rel="prev">Additional Features</a>, Up: <a href="#Top" accesskey="u" rel="up">GnuTLS</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h2 class="unnumbered" id="Bibliography-1"><span>Bibliography<a class="copiable-link" href="#Bibliography-1"> &para;</a></span></h2>

<dl class="table">
<dt><a class="anchor" id="CBCATT"></a>[CBCATT]</dt>
<dd><p>Bodo Moeller, &quot;Security of CBC Ciphersuites in SSL/TLS: Problems and
Countermeasures&quot;, 2002, available from
<a class="url" href="https://www.openssl.org/~bodo/tls-cbc.txt">https://www.openssl.org/~bodo/tls-cbc.txt</a>.
</p>
</dd>
<dt><a class="anchor" id="GPGH"></a>[GPGH]</dt>
<dd><p>Mike Ashley, &quot;The GNU Privacy Handbook&quot;, 2002, available from
<a class="url" href="https://www.gnupg.org/gph/en/manual.pdf">https://www.gnupg.org/gph/en/manual.pdf</a>.
</p>
</dd>
<dt><a class="anchor" id="GUTPKI"></a>[GUTPKI]</dt>
<dd><p>Peter Gutmann, &quot;Everything you never wanted to know about PKI but were
forced to find out&quot;, Available from
<a class="url" href="https://www.cs.auckland.ac.nz/~pgut001/">https://www.cs.auckland.ac.nz/~pgut001/</a>.
</p>
</dd>
<dt><a class="anchor" id="PRNGATTACKS"></a>[PRNGATTACKS]</dt>
<dd><p>John Kelsey and Bruce Schneier, &quot;Cryptanalytic Attacks on Pseudorandom Number Generators&quot;,
Available from <a class="url" href="https://www.schneier.com/academic/paperfiles/paper-prngs.pdf">https://www.schneier.com/academic/paperfiles/paper-prngs.pdf</a>.
</p>
</dd>
<dt><a class="anchor" id="KEYPIN"></a>[KEYPIN]</dt>
<dd><p>Chris Evans and Chris Palmer, &quot;Public Key Pinning Extension for HTTP&quot;, 
Available from <a class="url" href="https://tools.ietf.org/html/draft-ietf-websec-key-pinning-01">https://tools.ietf.org/html/draft-ietf-websec-key-pinning-01</a>.
</p>
</dd>
<dt><a class="anchor" id="NISTSP80057"></a>[NISTSP80057]</dt>
<dd><p>NIST Special Publication 800-57, &quot;Recommendation for Key Management -
Part 1: General (Revised)&quot;, March 2007, available from
<a class="url" href="https://csrc.nist.gov/publications/nistpubs/800-57/sp800-57-Part1-revised2_Mar08-2007.pdf">https://csrc.nist.gov/publications/nistpubs/800-57/sp800-57-Part1-revised2_Mar08-2007.pdf</a>.
</p>
</dd>
<dt><a class="anchor" id="RFC7413"></a>[RFC7413]</dt>
<dd><p>Y. Cheng and J. Chu and S. Radhakrishnan and A. Jain, &quot;TCP Fast Open&quot;,
December 2014, Available from
<a class="url" href="https://www.ietf.org/rfc/rfc7413.txt">https://www.ietf.org/rfc/rfc7413.txt</a>.
</p>
</dd>
<dt><a class="anchor" id="RFC7918"></a>[RFC7918]</dt>
<dd><p>A. Langley, N. Modadugu, B. Moeller, &quot;Transport Layer Security (TLS) False Start&quot;,
August 2016, Available from
<a class="url" href="https://www.ietf.org/rfc/rfc7918.txt">https://www.ietf.org/rfc/rfc7918.txt</a>.
</p>
</dd>
<dt><a class="anchor" id="RFC6125"></a>[RFC6125]</dt>
<dd><p>Peter Saint-Andre and Jeff Hodges, &quot;Representation and Verification of Domain-Based Application Service Identity within Internet Public Key Infrastructure Using X.509 (PKIX) Certificates in the Context of Transport Layer Security (TLS)&quot;,
March 2011, Available from
<a class="url" href="https://www.ietf.org/rfc/rfc6125.txt">https://www.ietf.org/rfc/rfc6125.txt</a>.
</p>
</dd>
<dt><a class="anchor" id="RFC7685"></a>[RFC7685]</dt>
<dd><p>Adam Langley, &quot;A Transport Layer Security (TLS) ClientHello Padding Extension&quot;,
October 2015, Available from
<a class="url" href="https://www.ietf.org/rfc/rfc7685.txt">https://www.ietf.org/rfc/rfc7685.txt</a>.
</p>
</dd>
<dt><a class="anchor" id="RFC7613"></a>[RFC7613]</dt>
<dd><p>Peter Saint-Andre and Alexey Melnikov, &quot;Preparation, Enforcement, and Comparison of Internationalized Strings Representing Usernames and Passwords&quot;,
August 2015, Available from
<a class="url" href="https://www.ietf.org/rfc/rfc7613.txt">https://www.ietf.org/rfc/rfc7613.txt</a>.
</p>
</dd>
<dt><a class="anchor" id="RFC2246"></a>[RFC2246]</dt>
<dd><p>Tim Dierks and Christopher Allen, &quot;The TLS Protocol Version 1.0&quot;,
January 1999, Available from
<a class="url" href="https://www.ietf.org/rfc/rfc2246.txt">https://www.ietf.org/rfc/rfc2246.txt</a>.
</p>
</dd>
<dt><a class="anchor" id="RFC6083"></a>[RFC6083]</dt>
<dd><p>M. Tuexen and R. Seggelmann and E. Rescorla, &quot;Datagram Transport Layer Security (DTLS) for Stream Control Transmission Protocol (SCTP)&quot;,
January 2011, Available from
<a class="url" href="https://www.ietf.org/rfc/rfc6083.txt">https://www.ietf.org/rfc/rfc6083.txt</a>.
</p>
</dd>
<dt><a class="anchor" id="RFC4418"></a>[RFC4418]</dt>
<dd><p>Ted Krovetz, &quot;UMAC: Message Authentication Code using Universal Hashing&quot;,
March 2006, Available from
<a class="url" href="https://www.ietf.org/rfc/rfc4418.txt">https://www.ietf.org/rfc/rfc4418.txt</a>.
</p>
</dd>
<dt><a class="anchor" id="RFC4680"></a>[RFC4680]</dt>
<dd><p>S. Santesson, &quot;TLS Handshake Message for Supplemental Data&quot;,
September 2006, Available from
<a class="url" href="https://www.ietf.org/rfc/rfc4680.txt">https://www.ietf.org/rfc/rfc4680.txt</a>.
</p>
</dd>
<dt><a class="anchor" id="RFC7633"></a>[RFC7633]</dt>
<dd><p>P. Hallam-Baker, &quot;X.509v3 Transport Layer Security (TLS) Feature Extension&quot;,
October 2015, Available from
<a class="url" href="https://www.ietf.org/rfc/rfc7633.txt">https://www.ietf.org/rfc/rfc7633.txt</a>.
</p>
</dd>
<dt><a class="anchor" id="RFC7919"></a>[RFC7919]</dt>
<dd><p>D. Gillmor, &quot;Negotiated Finite Field Diffie-Hellman Ephemeral Parameters for Transport Layer Security (TLS)&quot;,
August 2016, Available from
<a class="url" href="https://www.ietf.org/rfc/rfc7919.txt">https://www.ietf.org/rfc/rfc7919.txt</a>.
</p>
</dd>
<dt><a class="anchor" id="RFC4514"></a>[RFC4514]</dt>
<dd><p>Kurt D.  Zeilenga, &quot;Lightweight Directory Access Protocol (LDAP): String Representation of Distinguished Names&quot;,
June 2006, Available from
<a class="url" href="https://www.ietf.org/rfc/rfc4513.txt">https://www.ietf.org/rfc/rfc4513.txt</a>.
</p>
</dd>
<dt><a class="anchor" id="RFC4346"></a>[RFC4346]</dt>
<dd><p>Tim Dierks and Eric Rescorla, &quot;The TLS Protocol Version 1.1&quot;, Match
2006, Available from <a class="url" href="https://www.ietf.org/rfc/rfc4346.txt">https://www.ietf.org/rfc/rfc4346.txt</a>.
</p>
</dd>
<dt><a class="anchor" id="RFC4347"></a>[RFC4347]</dt>
<dd><p>Eric Rescorla and Nagendra Modadugu, &quot;Datagram Transport Layer Security&quot;, April
2006, Available from <a class="url" href="https://www.ietf.org/rfc/rfc4347.txt">https://www.ietf.org/rfc/rfc4347.txt</a>.
</p>
</dd>
<dt><a class="anchor" id="RFC5246"></a>[RFC5246]</dt>
<dd><p>Tim Dierks and Eric Rescorla, &quot;The TLS Protocol Version 1.2&quot;, August
2008, Available from <a class="url" href="https://www.ietf.org/rfc/rfc5246.txt">https://www.ietf.org/rfc/rfc5246.txt</a>.
</p>
</dd>
<dt><a class="anchor" id="RFC2440"></a>[RFC2440]</dt>
<dd><p>Jon Callas, Lutz Donnerhacke, Hal Finney and Rodney Thayer, &quot;OpenPGP
Message Format&quot;, November 1998, Available from
<a class="url" href="https://www.ietf.org/rfc/rfc2440.txt">https://www.ietf.org/rfc/rfc2440.txt</a>.
</p>
</dd>
<dt><a class="anchor" id="RFC4880"></a>[RFC4880]</dt>
<dd><p>Jon Callas, Lutz Donnerhacke, Hal Finney, David Shaw and Rodney
Thayer, &quot;OpenPGP Message Format&quot;, November 2007, Available from
<a class="url" href="https://www.ietf.org/rfc/rfc4880.txt">https://www.ietf.org/rfc/rfc4880.txt</a>.
</p>
</dd>
<dt><a class="anchor" id="RFC4211"></a>[RFC4211]</dt>
<dd><p>J. Schaad, &quot;Internet X.509 Public Key Infrastructure Certificate
Request Message Format (CRMF)&quot;, September 2005, Available from
<a class="url" href="https://www.ietf.org/rfc/rfc4211.txt">https://www.ietf.org/rfc/rfc4211.txt</a>.
</p>
</dd>
<dt><a class="anchor" id="RFC2817"></a>[RFC2817]</dt>
<dd><p>Rohit Khare and Scott Lawrence, &quot;Upgrading to TLS Within HTTP/1.1&quot;,
May 2000, Available from <a class="url" href="https://www.ietf.org/rfc/rfc2817.txt">https://www.ietf.org/rfc/rfc2817.txt</a>
</p>
</dd>
<dt><a class="anchor" id="RFC2818"></a>[RFC2818]</dt>
<dd><p>Eric Rescorla, &quot;HTTP Over TLS&quot;, May 2000, Available from
<a class="url" href="https://www.ietf/rfc/rfc2818.txt">https://www.ietf/rfc/rfc2818.txt</a>.
</p>
</dd>
<dt><a class="anchor" id="RFC2945"></a>[RFC2945]</dt>
<dd><p>Tom Wu, &quot;The SRP Authentication and Key Exchange System&quot;, September
2000, Available from <a class="url" href="https://www.ietf.org/rfc/rfc2945.txt">https://www.ietf.org/rfc/rfc2945.txt</a>.
</p>
</dd>
<dt><a class="anchor" id="RFC7301"></a>[RFC7301]</dt>
<dd><p>S. Friedl, A. Popov, A. Langley, E. Stephan, &quot;Transport Layer Security (TLS) Application-Layer Protocol Negotiation Extension&quot;,
July 2014, Available from <a class="url" href="https://www.ietf.org/rfc/rfc7301.txt">https://www.ietf.org/rfc/rfc7301.txt</a>.
</p>
</dd>
<dt><a class="anchor" id="RFC2986"></a>[RFC2986]</dt>
<dd><p>Magnus Nystrom and Burt Kaliski, &quot;PKCS 10 v1.7: Certification Request
Syntax Specification&quot;, November 2000, Available from
<a class="url" href="https://www.ietf.org/rfc/rfc2986.txt">https://www.ietf.org/rfc/rfc2986.txt</a>.
</p>
</dd>
<dt><a class="anchor" id="PKIX"></a>[PKIX]</dt>
<dd><p>D. Cooper, S. Santesson, S. Farrel, S. Boeyen, R. Housley, W. Polk,
&quot;Internet X.509 Public Key Infrastructure Certificate and Certificate
Revocation List (CRL) Profile&quot;, May 2008, available from
<a class="url" href="https://www.ietf.org/rfc/rfc5280.txt">https://www.ietf.org/rfc/rfc5280.txt</a>.
</p>
</dd>
<dt><a class="anchor" id="RFC3749"></a>[RFC3749]</dt>
<dd><p>Scott Hollenbeck, &quot;Transport Layer Security Protocol Compression
Methods&quot;, May 2004, available from
<a class="url" href="https://www.ietf.org/rfc/rfc3749.txt">https://www.ietf.org/rfc/rfc3749.txt</a>.
</p>
</dd>
<dt><a class="anchor" id="RFC3820"></a>[RFC3820]</dt>
<dd><p>Steven Tuecke, Von Welch, Doug Engert, Laura Pearlman, and Mary
Thompson, &quot;Internet X.509 Public Key Infrastructure (PKI) Proxy
Certificate Profile&quot;, June 2004, available from
<a class="url" href="https://www.ietf.org/rfc/rfc3820">https://www.ietf.org/rfc/rfc3820</a>.
</p>
</dd>
<dt><a class="anchor" id="RFC6520"></a>[RFC6520]</dt>
<dd><p>R. Seggelmann, M. Tuexen, and M. Williams, &quot;Transport Layer Security (TLS) and
Datagram Transport Layer Security (DTLS) Heartbeat Extension&quot;, February 2012, available from
<a class="url" href="https://www.ietf.org/rfc/rfc6520">https://www.ietf.org/rfc/rfc6520</a>.
</p>

</dd>
<dt><a class="anchor" id="RFC5746"></a>[RFC5746]</dt>
<dd><p>E. Rescorla, M. Ray, S. Dispensa, and N. Oskov, &quot;Transport Layer
Security (TLS) Renegotiation Indication Extension&quot;, February 2010,
available from <a class="url" href="https://www.ietf.org/rfc/rfc5746">https://www.ietf.org/rfc/rfc5746</a>.
</p>
</dd>
<dt><a class="anchor" id="RFC5280"></a>[RFC5280]</dt>
<dd><p>D. Cooper, S. Santesson, S. Farrell, S. Boeyen, R. Housley, and
W. Polk, &quot;Internet X.509 Public Key Infrastructure Certificate and
Certificate Revocation List (CRL) Profile&quot;, May 2008, available from
<a class="url" href="https://www.ietf.org/rfc/rfc5280">https://www.ietf.org/rfc/rfc5280</a>.
</p>
</dd>
<dt><a class="anchor" id="TLSTKT"></a>[TLSTKT]</dt>
<dd><p>Joseph Salowey, Hao Zhou, Pasi Eronen, Hannes Tschofenig, &quot;Transport
Layer Security (TLS) Session Resumption without Server-Side State&quot;,
January 2008, available from <a class="url" href="https://www.ietf.org/rfc/rfc5077">https://www.ietf.org/rfc/rfc5077</a>.
</p>
</dd>
<dt><a class="anchor" id="PKCS12"></a>[PKCS12]</dt>
<dd><p>RSA Laboratories, &quot;PKCS 12 v1.0: Personal Information Exchange
Syntax&quot;, June 1999, Available from <a class="url" href="https://www.rsa.com">https://www.rsa.com</a>.
</p>
</dd>
<dt><a class="anchor" id="PKCS11"></a>[PKCS11]</dt>
<dd><p>RSA Laboratories, &quot;PKCS #11 Base Functionality v2.30: Cryptoki – Draft 4&quot;,
July 2009, Available from <a class="url" href="https://www.rsa.com">https://www.rsa.com</a>.
</p>
</dd>
<dt><a class="anchor" id="RESCORLA"></a>[RESCORLA]</dt>
<dd><p>Eric Rescorla, &quot;SSL and TLS: Designing and Building Secure Systems&quot;,
2001
</p>
</dd>
<dt><a class="anchor" id="SELKEY"></a>[SELKEY]</dt>
<dd><p>Arjen Lenstra and Eric Verheul, &quot;Selecting Cryptographic Key Sizes&quot;,
2003, available from <a class="url" href="https://www.win.tue.nl/~klenstra/key.pdf">https://www.win.tue.nl/~klenstra/key.pdf</a>.
</p>
</dd>
<dt><a class="anchor" id="SSL3"></a>[SSL3]</dt>
<dd><p>Alan Freier, Philip Karlton and Paul Kocher, &quot;The Secure Sockets Layer (SSL) Protocol Version 3.0&quot;,
August 2011, Available from <a class="url" href="https://www.ietf.org/rfc/rfc6101.txt">https://www.ietf.org/rfc/rfc6101.txt</a>.
</p>
</dd>
<dt><a class="anchor" id="STEVENS"></a>[STEVENS]</dt>
<dd><p>Richard Stevens, &quot;UNIX Network Programming, Volume 1&quot;, Prentice Hall
PTR, January 1998
</p>
</dd>
<dt><a class="anchor" id="TLSEXT"></a>[TLSEXT]</dt>
<dd><p>Simon Blake-Wilson, Magnus Nystrom, David Hopwood, Jan Mikkelsen and
Tim Wright, &quot;Transport Layer Security (TLS) Extensions&quot;, June 2003,
Available from <a class="url" href="https://www.ietf.org/rfc/rfc3546.txt">https://www.ietf.org/rfc/rfc3546.txt</a>.
</p>
</dd>
<dt><a class="anchor" id="TLSPGP"></a>[TLSPGP]</dt>
<dd><p>Nikos Mavrogiannopoulos, &quot;Using OpenPGP keys for TLS authentication&quot;,
January 2011. Available from
<a class="url" href="https://www.ietf.org/rfc/rfc6091.txt">https://www.ietf.org/rfc/rfc6091.txt</a>.
</p>
</dd>
<dt><a class="anchor" id="TLSSRP"></a>[TLSSRP]</dt>
<dd><p>David Taylor, Trevor Perrin, Tom Wu and Nikos Mavrogiannopoulos,
&quot;Using SRP for TLS Authentication&quot;, November 2007. Available from
<a class="url" href="https://www.ietf.org/rfc/rfc5054.txt">https://www.ietf.org/rfc/rfc5054.txt</a>.
</p>
</dd>
<dt><a class="anchor" id="TLSPSK"></a>[TLSPSK]</dt>
<dd><p>Pasi Eronen and Hannes Tschofenig, &quot;Pre-shared key Ciphersuites for
TLS&quot;, December 2005, Available from
<a class="url" href="https://www.ietf.org/rfc/rfc4279.txt">https://www.ietf.org/rfc/rfc4279.txt</a>.
</p>
</dd>
<dt><a class="anchor" id="TOMSRP"></a>[TOMSRP]</dt>
<dd><p>Tom Wu, &quot;The Stanford SRP Authentication Project&quot;, Available at
<a class="url" href="https://srp.stanford.edu/">https://srp.stanford.edu/</a>.
</p>
</dd>
<dt><a class="anchor" id="WEGER"></a>[WEGER]</dt>
<dd><p>Arjen Lenstra and Xiaoyun Wang and Benne de Weger, &quot;Colliding X.509
Certificates&quot;, Cryptology ePrint Archive, Report 2005/067, Available
at <a class="url" href="https://eprint.iacr.org/">https://eprint.iacr.org/</a>.
</p>
</dd>
<dt><a class="anchor" id="ECRYPT"></a>[ECRYPT]</dt>
<dd><p>European Network of Excellence in Cryptology II, &quot;ECRYPT II Yearly
Report on Algorithms and Keysizes (2009-2010)&quot;, Available
at <a class="url" href="https://www.ecrypt.eu.org/documents/D.SPA.13.pdf">https://www.ecrypt.eu.org/documents/D.SPA.13.pdf</a>.
</p>
</dd>
<dt><a class="anchor" id="RFC5056"></a>[RFC5056]</dt>
<dd><p>N. Williams, &quot;On the Use of Channel Bindings to Secure Channels&quot;,
November 2007, available from <a class="url" href="https://www.ietf.org/rfc/rfc5056">https://www.ietf.org/rfc/rfc5056</a>.
</p>
</dd>
<dt><a class="anchor" id="RFC5764"></a>[RFC5764]</dt>
<dd><p>D. McGrew, E. Rescorla, &quot;Datagram Transport Layer Security (DTLS) Extension to Establish Keys for the Secure Real-time Transport Protocol (SRTP)On the Use of Channel Bindings to Secure Channels&quot;,
May 2010, available from <a class="url" href="https://www.ietf.org/rfc/rfc5764">https://www.ietf.org/rfc/rfc5764</a>.
</p>
</dd>
<dt><a class="anchor" id="RFC5929"></a>[RFC5929]</dt>
<dd><p>J. Altman, N. Williams, L. Zhu, &quot;Channel Bindings for TLS&quot;, July 2010,
available from <a class="url" href="https://www.ietf.org/rfc/rfc5929">https://www.ietf.org/rfc/rfc5929</a>.
</p>
</dd>
<dt><a class="anchor" id="PKCS11URI"></a>[PKCS11URI]</dt>
<dd><p>J. Pechanec, D. Moffat, &quot;The PKCS#11 URI Scheme&quot;, April 2015,
available from <a class="url" href="https://www.ietf.org/rfc/rfc7512">https://www.ietf.org/rfc/rfc7512</a>.
</p>
</dd>
<dt><a class="anchor" id="TPMURI"></a>[TPMURI]</dt>
<dd><p>C. Latze, N. Mavrogiannopoulos, &quot;The TPMKEY URI Scheme&quot;, January 2013,
Work in progress, available from <a class="url" href="https://tools.ietf.org/html/draft-mavrogiannopoulos-tpmuri-01">https://tools.ietf.org/html/draft-mavrogiannopoulos-tpmuri-01</a>.
</p>
</dd>
<dt><a class="anchor" id="ANDERSON"></a>[ANDERSON]</dt>
<dd><p>R. J. Anderson, &quot;Security Engineering: A Guide to Building Dependable Distributed Systems&quot;, 
John Wiley \&amp; Sons, Inc., 2001.
</p>
</dd>
<dt><a class="anchor" id="RFC4821"></a>[RFC4821]</dt>
<dd><p>M. Mathis, J. Heffner, &quot;Packetization Layer Path MTU Discovery&quot;, March 2007,
available from <a class="url" href="https://www.ietf.org/rfc/rfc4821.txt">https://www.ietf.org/rfc/rfc4821.txt</a>.
</p>
</dd>
<dt><a class="anchor" id="RFC2560"></a>[RFC2560]</dt>
<dd><p>M. Myers et al, &quot;X.509 Internet Public Key Infrastructure Online
Certificate Status Protocol - OCSP&quot;, June 1999, Available from
<a class="url" href="https://www.ietf.org/rfc/rfc2560.txt">https://www.ietf.org/rfc/rfc2560.txt</a>.
</p>
</dd>
<dt><a class="anchor" id="RIVESTCRL"></a>[RIVESTCRL]</dt>
<dd><p>R. L. Rivest, &quot;Can We Eliminate Certificate Revocation Lists?&quot;,
Proceedings of Financial Cryptography &rsquo;98; Springer Lecture Notes in
Computer Science No. 1465 (Rafael Hirschfeld, ed.), February 1998),
pages 178&ndash;183, available from
<a class="url" href="https://people.csail.mit.edu/rivest/Rivest-CanWeEliminateCertificateRevocationLists.pdf">https://people.csail.mit.edu/rivest/Rivest-CanWeEliminateCertificateRevocationLists.pdf</a>.
</p>
</dd>
<dt><a class="anchor" id="RFC9266"></a>[RFC9266]</dt>
<dd><p>S. Whited, &quot;Channel Bindings for TLS 1.3&quot;,
July 2022, available from <a class="url" href="https://www.ietf.org/rfc/rfc9266.txt">https://www.ietf.org/rfc/rfc9266.txt</a>.
</p>
</dd>
</dl>

<hr>
</div>
<div class="unnumbered-level-extent" id="Function-and-Data-Index">
<div class="nav-panel">
<p>
Next: <a href="#Concept-Index" accesskey="n" rel="next">Concept Index</a>, Previous: <a href="#Bibliography" accesskey="p" rel="prev">Bibliography</a>, Up: <a href="#Top" accesskey="u" rel="up">GnuTLS</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
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<h2 class="unnumbered" id="Function-and-Data-Index-1"><span>Function and Data Index<a class="copiable-link" href="#Function-and-Data-Index-1"> &para;</a></span></h2>

<div class="printindex fn-printindex">
<table class="fn-letters-header-printindex"><tr><th>Jump to: &nbsp; </th><td><a class="summary-letter-printindex" href="#Function-and-Data-Index_fn_letter-D"><b>D</b></a>
 &nbsp; 
<a class="summary-letter-printindex" href="#Function-and-Data-Index_fn_letter-G"><b>G</b></a>
 &nbsp; 
</td></tr></table>
<table class="fn-entries-printindex">
<tr><td></td><th class="entries-header-printindex">Index Entry</th><th class="sections-header-printindex">Section</th></tr>
<tr><td colspan="3"><hr></td></tr>
<tr><th id="Function-and-Data-Index_fn_letter-D">D</th></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-dane_005fcert_005ftype_005fname"><code>dane_cert_type_name</code></a></td><td class="printindex-index-section"><a href="#DANE-API">DANE API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-dane_005fcert_005fusage_005fname"><code>dane_cert_usage_name</code></a></td><td class="printindex-index-section"><a href="#DANE-API">DANE API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-dane_005fmatch_005ftype_005fname"><code>dane_match_type_name</code></a></td><td class="printindex-index-section"><a href="#DANE-API">DANE API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-dane_005fquery_005fdata"><code>dane_query_data</code></a></td><td class="printindex-index-section"><a href="#DANE-API">DANE API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-dane_005fquery_005fdeinit"><code>dane_query_deinit</code></a></td><td class="printindex-index-section"><a href="#DANE-API">DANE API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-dane_005fquery_005fentries"><code>dane_query_entries</code></a></td><td class="printindex-index-section"><a href="#DANE-API">DANE API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-dane_005fquery_005fstatus"><code>dane_query_status</code></a></td><td class="printindex-index-section"><a href="#DANE-API">DANE API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-dane_005fquery_005ftlsa"><code>dane_query_tlsa</code></a></td><td class="printindex-index-section"><a href="#DANE-API">DANE API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-dane_005fquery_005fto_005fraw_005ftlsa"><code>dane_query_to_raw_tlsa</code></a></td><td class="printindex-index-section"><a href="#DANE-API">DANE API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-dane_005fraw_005ftlsa"><code>dane_raw_tlsa</code></a></td><td class="printindex-index-section"><a href="#DANE-API">DANE API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-dane_005fstate_005fdeinit"><code>dane_state_deinit</code></a></td><td class="printindex-index-section"><a href="#DANE-API">DANE API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-dane_005fstate_005finit"><code>dane_state_init</code></a></td><td class="printindex-index-section"><a href="#DANE-API">DANE API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-dane_005fstate_005fset_005fdlv_005ffile"><code>dane_state_set_dlv_file</code></a></td><td class="printindex-index-section"><a href="#DANE-API">DANE API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-dane_005fstrerror"><code>dane_strerror</code></a></td><td class="printindex-index-section"><a href="#DANE-API">DANE API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-dane_005fverification_005fstatus_005fprint"><code>dane_verification_status_print</code></a></td><td class="printindex-index-section"><a href="#DANE-API">DANE API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-dane_005fverify_005fcrt"><code>dane_verify_crt</code></a></td><td class="printindex-index-section"><a href="#Certificate-verification">Certificate verification</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-dane_005fverify_005fcrt-1"><code>dane_verify_crt</code></a></td><td class="printindex-index-section"><a href="#DANE-API">DANE API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-dane_005fverify_005fcrt_005fraw"><code>dane_verify_crt_raw</code></a></td><td class="printindex-index-section"><a href="#DANE-API">DANE API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-dane_005fverify_005fsession_005fcrt"><code>dane_verify_session_crt</code></a></td><td class="printindex-index-section"><a href="#DANE-API">DANE API</a></td></tr>
<tr><td colspan="3"><hr></td></tr>
<tr><th id="Function-and-Data-Index_fn_letter-G">G</th></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005faead_005fcipher_005fdecrypt"><code>gnutls_aead_cipher_decrypt</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005faead_005fcipher_005fdecryptv2"><code>gnutls_aead_cipher_decryptv2</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005faead_005fcipher_005fdeinit"><code>gnutls_aead_cipher_deinit</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005faead_005fcipher_005fencrypt"><code>gnutls_aead_cipher_encrypt</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005faead_005fcipher_005fencryptv"><code>gnutls_aead_cipher_encryptv</code></a></td><td class="printindex-index-section"><a href="#Symmetric-algorithms">Symmetric algorithms</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005faead_005fcipher_005fencryptv-1"><code>gnutls_aead_cipher_encryptv</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005faead_005fcipher_005fencryptv2"><code>gnutls_aead_cipher_encryptv2</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005faead_005fcipher_005finit"><code>gnutls_aead_cipher_init</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005faead_005fcipher_005fset_005fkey"><code>gnutls_aead_cipher_set_key</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005falert_005fget"><code>gnutls_alert_get</code></a></td><td class="printindex-index-section"><a href="#Handling-alerts">Handling alerts</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005falert_005fget-1"><code>gnutls_alert_get</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005falert_005fget_005fname"><code>gnutls_alert_get_name</code></a></td><td class="printindex-index-section"><a href="#Handling-alerts">Handling alerts</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005falert_005fget_005fname-1"><code>gnutls_alert_get_name</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005falert_005fget_005fstrname"><code>gnutls_alert_get_strname</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005falert_005fsend"><code>gnutls_alert_send</code></a></td><td class="printindex-index-section"><a href="#Handling-alerts">Handling alerts</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005falert_005fsend-1"><code>gnutls_alert_send</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005falert_005fsend_005fappropriate"><code>gnutls_alert_send_appropriate</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005falert_005fset_005fread_005ffunction"><code>gnutls_alert_set_read_function</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005falpn_005fget_005fselected_005fprotocol"><code>gnutls_alpn_get_selected_protocol</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005falpn_005fset_005fprotocols"><code>gnutls_alpn_set_protocols</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fanon_005fallocate_005fclient_005fcredentials"><code>gnutls_anon_allocate_client_credentials</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fanon_005fallocate_005fserver_005fcredentials"><code>gnutls_anon_allocate_server_credentials</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fanon_005ffree_005fclient_005fcredentials"><code>gnutls_anon_free_client_credentials</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fanon_005ffree_005fserver_005fcredentials"><code>gnutls_anon_free_server_credentials</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fanon_005fset_005fparams_005ffunction"><code>gnutls_anon_set_params_function</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fanon_005fset_005fserver_005fdh_005fparams"><code>gnutls_anon_set_server_dh_params</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fanon_005fset_005fserver_005fknown_005fdh_005fparams"><code>gnutls_anon_set_server_known_dh_params</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fanon_005fset_005fserver_005fparams_005ffunction"><code>gnutls_anon_set_server_params_function</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fanti_005freplay_005fdeinit"><code>gnutls_anti_replay_deinit</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fanti_005freplay_005fenable"><code>gnutls_anti_replay_enable</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fanti_005freplay_005finit"><code>gnutls_anti_replay_init</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fanti_005freplay_005fset_005fadd_005ffunction"><code>gnutls_anti_replay_set_add_function</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fanti_005freplay_005fset_005fptr"><code>gnutls_anti_replay_set_ptr</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fanti_005freplay_005fset_005fwindow"><code>gnutls_anti_replay_set_window</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005faudit_005fcurrent_005fcontext"><code>gnutls_audit_current_context</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005faudit_005fpop_005fcontext"><code>gnutls_audit_pop_context</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005faudit_005fpush_005fcontext"><code>gnutls_audit_push_context</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fauth_005fclient_005fget_005ftype"><code>gnutls_auth_client_get_type</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fauth_005fget_005ftype"><code>gnutls_auth_get_type</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fauth_005fserver_005fget_005ftype"><code>gnutls_auth_server_get_type</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fbase64_005fdecode2"><code>gnutls_base64_decode2</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fbase64_005fencode2"><code>gnutls_base64_encode2</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fbuffer_005fappend_005fdata"><code>gnutls_buffer_append_data</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fbye"><code>gnutls_bye</code></a></td><td class="printindex-index-section"><a href="#Data-transfer-and-termination">Data transfer and termination</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fbye-1"><code>gnutls_bye</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005factivation_005ftime_005fpeers"><code>gnutls_certificate_activation_time_peers</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fallocate_005fcredentials"><code>gnutls_certificate_allocate_credentials</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fclient_005fget_005frequest_005fstatus"><code>gnutls_certificate_client_get_request_status</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fexpiration_005ftime_005fpeers"><code>gnutls_certificate_expiration_time_peers</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005ffree_005fca_005fnames"><code>gnutls_certificate_free_ca_names</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005ffree_005fcas"><code>gnutls_certificate_free_cas</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005ffree_005fcredentials"><code>gnutls_certificate_free_credentials</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005ffree_005fcrls"><code>gnutls_certificate_free_crls</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005ffree_005fkeys"><code>gnutls_certificate_free_keys</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fget_005fcrt_005fraw"><code>gnutls_certificate_get_crt_raw</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fget_005fissuer"><code>gnutls_certificate_get_issuer</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fget_005focsp_005fexpiration"><code>gnutls_certificate_get_ocsp_expiration</code></a></td><td class="printindex-index-section"><a href="#OCSP-stapling">OCSP stapling</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fget_005focsp_005fexpiration-1"><code>gnutls_certificate_get_ocsp_expiration</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fget_005fours"><code>gnutls_certificate_get_ours</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fget_005fpeers"><code>gnutls_certificate_get_peers</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fget_005fpeers_005fsubkey_005fid"><code>gnutls_certificate_get_peers_subkey_id</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fget_005ftrust_005flist"><code>gnutls_certificate_get_trust_list</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fget_005fverify_005fflags"><code>gnutls_certificate_get_verify_flags</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fget_005fx509_005fcrt"><code>gnutls_certificate_get_x509_crt</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fget_005fx509_005fkey"><code>gnutls_certificate_get_x509_key</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fsend_005fx509_005frdn_005fsequence"><code>gnutls_certificate_send_x509_rdn_sequence</code></a></td><td class="printindex-index-section"><a href="#Certificate-credentials">Certificate credentials</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fsend_005fx509_005frdn_005fsequence-1"><code>gnutls_certificate_send_x509_rdn_sequence</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fserver_005fset_005frequest"><code>gnutls_certificate_server_set_request</code></a></td><td class="printindex-index-section"><a href="#Certificate-credentials">Certificate credentials</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fserver_005fset_005frequest-1"><code>gnutls_certificate_server_set_request</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fset_005fdh_005fparams"><code>gnutls_certificate_set_dh_params</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fset_005fflags"><code>gnutls_certificate_set_flags</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fset_005fkey"><code>gnutls_certificate_set_key</code></a></td><td class="printindex-index-section"><a href="#Certificate-credentials">Certificate credentials</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fset_005fkey-1"><code>gnutls_certificate_set_key</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fset_005fknown_005fdh_005fparams"><code>gnutls_certificate_set_known_dh_params</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fset_005focsp_005fstatus_005frequest_005ffile"><code>gnutls_certificate_set_ocsp_status_request_file</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fset_005focsp_005fstatus_005frequest_005ffile2"><code>gnutls_certificate_set_ocsp_status_request_file2</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fset_005focsp_005fstatus_005frequest_005ffunction"><code>gnutls_certificate_set_ocsp_status_request_function</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fset_005focsp_005fstatus_005frequest_005ffunction2"><code>gnutls_certificate_set_ocsp_status_request_function2</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fset_005focsp_005fstatus_005frequest_005fmem"><code>gnutls_certificate_set_ocsp_status_request_mem</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fset_005fparams_005ffunction"><code>gnutls_certificate_set_params_function</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fset_005fpin_005ffunction"><code>gnutls_certificate_set_pin_function</code></a></td><td class="printindex-index-section"><a href="#Certificate-credentials">Certificate credentials</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fset_005fpin_005ffunction-1"><code>gnutls_certificate_set_pin_function</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fset_005frawpk_005fkey_005ffile"><code>gnutls_certificate_set_rawpk_key_file</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fset_005frawpk_005fkey_005fmem"><code>gnutls_certificate_set_rawpk_key_mem</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fset_005fretrieve_005ffunction"><code>gnutls_certificate_set_retrieve_function</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fset_005fretrieve_005ffunction2"><code>gnutls_certificate_set_retrieve_function2</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fset_005fretrieve_005ffunction3"><code>gnutls_certificate_set_retrieve_function3</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fset_005ftrust_005flist"><code>gnutls_certificate_set_trust_list</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fset_005fverify_005fflags"><code>gnutls_certificate_set_verify_flags</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fset_005fverify_005ffunction"><code>gnutls_certificate_set_verify_function</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fset_005fverify_005flimits"><code>gnutls_certificate_set_verify_limits</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fset_005fx509_005fcrl"><code>gnutls_certificate_set_x509_crl</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fset_005fx509_005fcrl_005ffile"><code>gnutls_certificate_set_x509_crl_file</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fset_005fx509_005fcrl_005fmem"><code>gnutls_certificate_set_x509_crl_mem</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fset_005fx509_005fkey"><code>gnutls_certificate_set_x509_key</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fset_005fx509_005fkey_005ffile"><code>gnutls_certificate_set_x509_key_file</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fset_005fx509_005fkey_005ffile2"><code>gnutls_certificate_set_x509_key_file2</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fset_005fx509_005fkey_005fmem"><code>gnutls_certificate_set_x509_key_mem</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fset_005fx509_005fkey_005fmem2"><code>gnutls_certificate_set_x509_key_mem2</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fset_005fx509_005fsimple_005fpkcs12_005ffile"><code>gnutls_certificate_set_x509_simple_pkcs12_file</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fset_005fx509_005fsimple_005fpkcs12_005fmem"><code>gnutls_certificate_set_x509_simple_pkcs12_mem</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fset_005fx509_005fsystem_005ftrust"><code>gnutls_certificate_set_x509_system_trust</code></a></td><td class="printindex-index-section"><a href="#Certificate-credentials">Certificate credentials</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fset_005fx509_005fsystem_005ftrust-1"><code>gnutls_certificate_set_x509_system_trust</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fset_005fx509_005ftrust"><code>gnutls_certificate_set_x509_trust</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fset_005fx509_005ftrust_005fdir"><code>gnutls_certificate_set_x509_trust_dir</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fset_005fx509_005ftrust_005ffile"><code>gnutls_certificate_set_x509_trust_file</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fset_005fx509_005ftrust_005fmem"><code>gnutls_certificate_set_x509_trust_mem</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005ftype_005fget"><code>gnutls_certificate_type_get</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005ftype_005fget_005fid"><code>gnutls_certificate_type_get_id</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005ftype_005fget_005fname"><code>gnutls_certificate_type_get_name</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005ftype_005fget2"><code>gnutls_certificate_type_get2</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005ftype_005flist"><code>gnutls_certificate_type_list</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fverification_005fprofile_005fget_005fid"><code>gnutls_certificate_verification_profile_get_id</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fverification_005fprofile_005fget_005fname"><code>gnutls_certificate_verification_profile_get_name</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fverification_005fstatus_005fprint"><code>gnutls_certificate_verification_status_print</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fverify_005fflags"><code>gnutls_certificate_verify_flags</code></a></td><td class="printindex-index-section"><a href="#Verifying-a-certificate-in-the-context-of-TLS-session">Verifying a certificate in the context of TLS session</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fverify_005fflags-1"><code>gnutls_certificate_verify_flags</code></a></td><td class="printindex-index-section"><a href="#Certificate-verification">Certificate verification</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fverify_005fpeers"><code>gnutls_certificate_verify_peers</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fverify_005fpeers2"><code>gnutls_certificate_verify_peers2</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcertificate_005fverify_005fpeers3"><code>gnutls_certificate_verify_peers3</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcheck_005fversion"><code>gnutls_check_version</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcipher_005fadd_005fauth"><code>gnutls_cipher_add_auth</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcipher_005fdecrypt"><code>gnutls_cipher_decrypt</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcipher_005fdecrypt2"><code>gnutls_cipher_decrypt2</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcipher_005fdecrypt3"><code>gnutls_cipher_decrypt3</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcipher_005fdeinit"><code>gnutls_cipher_deinit</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcipher_005fencrypt"><code>gnutls_cipher_encrypt</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcipher_005fencrypt2"><code>gnutls_cipher_encrypt2</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcipher_005fencrypt3"><code>gnutls_cipher_encrypt3</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcipher_005fget"><code>gnutls_cipher_get</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcipher_005fget_005fblock_005fsize"><code>gnutls_cipher_get_block_size</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcipher_005fget_005fid"><code>gnutls_cipher_get_id</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcipher_005fget_005fiv_005fsize"><code>gnutls_cipher_get_iv_size</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcipher_005fget_005fkey_005fsize"><code>gnutls_cipher_get_key_size</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcipher_005fget_005fname"><code>gnutls_cipher_get_name</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcipher_005fget_005ftag_005fsize"><code>gnutls_cipher_get_tag_size</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcipher_005finit"><code>gnutls_cipher_init</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcipher_005flist"><code>gnutls_cipher_list</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcipher_005fset_005fiv"><code>gnutls_cipher_set_iv</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcipher_005fsuite_005fget_005fname"><code>gnutls_cipher_suite_get_name</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcipher_005fsuite_005finfo"><code>gnutls_cipher_suite_info</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcipher_005ftag"><code>gnutls_cipher_tag</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fciphersuite_005fget"><code>gnutls_ciphersuite_get</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcompress_005fcertificate_005fget_005fselected_005fmethod"><code>gnutls_compress_certificate_get_selected_method</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcompress_005fcertificate_005fset_005fmethods"><code>gnutls_compress_certificate_set_methods</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcompression_005fget"><code>gnutls_compression_get</code></a></td><td class="printindex-index-section"><a href="#Compatibility-API">Compatibility API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcompression_005fget_005fid"><code>gnutls_compression_get_id</code></a></td><td class="printindex-index-section"><a href="#Compatibility-API">Compatibility API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcompression_005fget_005fname"><code>gnutls_compression_get_name</code></a></td><td class="printindex-index-section"><a href="#Compatibility-API">Compatibility API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcompression_005flist"><code>gnutls_compression_list</code></a></td><td class="printindex-index-section"><a href="#Compatibility-API">Compatibility API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcredentials_005fclear"><code>gnutls_credentials_clear</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcredentials_005fget"><code>gnutls_credentials_get</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcredentials_005fset"><code>gnutls_credentials_set</code></a></td><td class="printindex-index-section"><a href="#Session-initialization">Session initialization</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcredentials_005fset-1"><code>gnutls_credentials_set</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcrypto_005fregister_005faead_005fcipher"><code>gnutls_crypto_register_aead_cipher</code></a></td><td class="printindex-index-section"><a href="#Overriding-algorithms">Overriding algorithms</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcrypto_005fregister_005faead_005fcipher-1"><code>gnutls_crypto_register_aead_cipher</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcrypto_005fregister_005fcipher"><code>gnutls_crypto_register_cipher</code></a></td><td class="printindex-index-section"><a href="#Overriding-algorithms">Overriding algorithms</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcrypto_005fregister_005fcipher-1"><code>gnutls_crypto_register_cipher</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcrypto_005fregister_005fdigest"><code>gnutls_crypto_register_digest</code></a></td><td class="printindex-index-section"><a href="#Overriding-algorithms">Overriding algorithms</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcrypto_005fregister_005fdigest-1"><code>gnutls_crypto_register_digest</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcrypto_005fregister_005fmac"><code>gnutls_crypto_register_mac</code></a></td><td class="printindex-index-section"><a href="#Overriding-algorithms">Overriding algorithms</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fcrypto_005fregister_005fmac-1"><code>gnutls_crypto_register_mac</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdb_005fcheck_005fentry"><code>gnutls_db_check_entry</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdb_005fcheck_005fentry_005fexpire_005ftime"><code>gnutls_db_check_entry_expire_time</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdb_005fcheck_005fentry_005ftime"><code>gnutls_db_check_entry_time</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdb_005fget_005fdefault_005fcache_005fexpiration"><code>gnutls_db_get_default_cache_expiration</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdb_005fget_005fptr"><code>gnutls_db_get_ptr</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdb_005fremove_005fsession"><code>gnutls_db_remove_session</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdb_005fset_005fcache_005fexpiration"><code>gnutls_db_set_cache_expiration</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdb_005fset_005fptr"><code>gnutls_db_set_ptr</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdb_005fset_005fremove_005ffunction"><code>gnutls_db_set_remove_function</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdb_005fset_005fretrieve_005ffunction"><code>gnutls_db_set_retrieve_function</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdb_005fset_005fstore_005ffunction"><code>gnutls_db_set_store_function</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdecode_005fber_005fdigest_005finfo"><code>gnutls_decode_ber_digest_info</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdecode_005fgost_005frs_005fvalue"><code>gnutls_decode_gost_rs_value</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdecode_005frs_005fvalue"><code>gnutls_decode_rs_value</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdeinit"><code>gnutls_deinit</code></a></td><td class="printindex-index-section"><a href="#Data-transfer-and-termination">Data transfer and termination</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdeinit-1"><code>gnutls_deinit</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdh_005fget_005fgroup"><code>gnutls_dh_get_group</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdh_005fget_005fpeers_005fpublic_005fbits"><code>gnutls_dh_get_peers_public_bits</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdh_005fget_005fprime_005fbits"><code>gnutls_dh_get_prime_bits</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdh_005fget_005fpubkey"><code>gnutls_dh_get_pubkey</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdh_005fget_005fsecret_005fbits"><code>gnutls_dh_get_secret_bits</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdh_005fparams_005fcpy"><code>gnutls_dh_params_cpy</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdh_005fparams_005fdeinit"><code>gnutls_dh_params_deinit</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdh_005fparams_005fexport_005fpkcs3"><code>gnutls_dh_params_export_pkcs3</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdh_005fparams_005fexport_005fraw"><code>gnutls_dh_params_export_raw</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdh_005fparams_005fexport2_005fpkcs3"><code>gnutls_dh_params_export2_pkcs3</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdh_005fparams_005fgenerate2"><code>gnutls_dh_params_generate2</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdh_005fparams_005fimport_005fdsa"><code>gnutls_dh_params_import_dsa</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdh_005fparams_005fimport_005fpkcs3"><code>gnutls_dh_params_import_pkcs3</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdh_005fparams_005fimport_005fraw"><code>gnutls_dh_params_import_raw</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdh_005fparams_005fimport_005fraw2"><code>gnutls_dh_params_import_raw2</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdh_005fparams_005fimport_005fraw3"><code>gnutls_dh_params_import_raw3</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdh_005fparams_005finit"><code>gnutls_dh_params_init</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdh_005fset_005fprime_005fbits"><code>gnutls_dh_set_prime_bits</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdigest_005fget_005fid"><code>gnutls_digest_get_id</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdigest_005fget_005fname"><code>gnutls_digest_get_name</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdigest_005fget_005foid"><code>gnutls_digest_get_oid</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdigest_005flist"><code>gnutls_digest_list</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdigest_005fset_005fsecure"><code>gnutls_digest_set_secure</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdtls_005fcookie_005fsend"><code>gnutls_dtls_cookie_send</code></a></td><td class="printindex-index-section"><a href="#Datagram-TLS-API">Datagram TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdtls_005fcookie_005fverify"><code>gnutls_dtls_cookie_verify</code></a></td><td class="printindex-index-section"><a href="#Datagram-TLS-API">Datagram TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdtls_005fget_005fdata_005fmtu"><code>gnutls_dtls_get_data_mtu</code></a></td><td class="printindex-index-section"><a href="#Datagram-TLS-API">Datagram TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdtls_005fget_005fmtu"><code>gnutls_dtls_get_mtu</code></a></td><td class="printindex-index-section"><a href="#Datagram-TLS-API">Datagram TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdtls_005fget_005ftimeout"><code>gnutls_dtls_get_timeout</code></a></td><td class="printindex-index-section"><a href="#Setting-up-the-transport-layer">Setting up the transport layer</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdtls_005fget_005ftimeout-1"><code>gnutls_dtls_get_timeout</code></a></td><td class="printindex-index-section"><a href="#Datagram-TLS-API">Datagram TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdtls_005fprestate_005fset"><code>gnutls_dtls_prestate_set</code></a></td><td class="printindex-index-section"><a href="#Datagram-TLS-API">Datagram TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdtls_005fset_005fdata_005fmtu"><code>gnutls_dtls_set_data_mtu</code></a></td><td class="printindex-index-section"><a href="#Datagram-TLS-API">Datagram TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdtls_005fset_005fmtu"><code>gnutls_dtls_set_mtu</code></a></td><td class="printindex-index-section"><a href="#Datagram-TLS-API">Datagram TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdtls_005fset_005ftimeouts"><code>gnutls_dtls_set_timeouts</code></a></td><td class="printindex-index-section"><a href="#Datagram-TLS-API">Datagram TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fearly_005fcipher_005fget"><code>gnutls_early_cipher_get</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fearly_005fprf_005fhash_005fget"><code>gnutls_early_prf_hash_get</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fecc_005fcurve_005fget"><code>gnutls_ecc_curve_get</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fecc_005fcurve_005fget_005fid"><code>gnutls_ecc_curve_get_id</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fecc_005fcurve_005fget_005fname"><code>gnutls_ecc_curve_get_name</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fecc_005fcurve_005fget_005foid"><code>gnutls_ecc_curve_get_oid</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fecc_005fcurve_005fget_005fpk"><code>gnutls_ecc_curve_get_pk</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fecc_005fcurve_005fget_005fsize"><code>gnutls_ecc_curve_get_size</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fecc_005fcurve_005flist"><code>gnutls_ecc_curve_list</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fecc_005fcurve_005fset_005fenabled"><code>gnutls_ecc_curve_set_enabled</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fencode_005fber_005fdigest_005finfo"><code>gnutls_encode_ber_digest_info</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fencode_005fgost_005frs_005fvalue"><code>gnutls_encode_gost_rs_value</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fencode_005frs_005fvalue"><code>gnutls_encode_rs_value</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ferror_005fis_005ffatal"><code>gnutls_error_is_fatal</code></a></td><td class="printindex-index-section"><a href="#Data-transfer-and-termination">Data transfer and termination</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ferror_005fis_005ffatal-1"><code>gnutls_error_is_fatal</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ferror_005fto_005falert"><code>gnutls_error_to_alert</code></a></td><td class="printindex-index-section"><a href="#Handling-alerts">Handling alerts</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ferror_005fto_005falert-1"><code>gnutls_error_to_alert</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fest_005frecord_005foverhead_005fsize"><code>gnutls_est_record_overhead_size</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fext_005fget_005fcurrent_005fmsg"><code>gnutls_ext_get_current_msg</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fext_005fget_005fdata"><code>gnutls_ext_get_data</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fext_005fget_005fname"><code>gnutls_ext_get_name</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fext_005fget_005fname2"><code>gnutls_ext_get_name2</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fext_005fraw_005fparse"><code>gnutls_ext_raw_parse</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fext_005fregister"><code>gnutls_ext_register</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fext_005fset_005fdata"><code>gnutls_ext_set_data</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ffingerprint"><code>gnutls_fingerprint</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ffips140_005fcontext_005fdeinit"><code>gnutls_fips140_context_deinit</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ffips140_005fcontext_005finit"><code>gnutls_fips140_context_init</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ffips140_005fget_005foperation_005fstate"><code>gnutls_fips140_get_operation_state</code></a></td><td class="printindex-index-section"><a href="#FIPS140_002d2-mode">FIPS140-2 mode</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ffips140_005fget_005foperation_005fstate-1"><code>gnutls_fips140_get_operation_state</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ffips140_005fmode_005fenabled"><code>gnutls_fips140_mode_enabled</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ffips140_005fpop_005fcontext"><code>gnutls_fips140_pop_context</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ffips140_005fpush_005fcontext"><code>gnutls_fips140_push_context</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ffips140_005frun_005fself_005ftests"><code>gnutls_fips140_run_self_tests</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ffips140_005fset_005fmode"><code>gnutls_fips140_set_mode</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fget_005flibrary_005fconfig"><code>gnutls_get_library_config</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fget_005fsystem_005fconfig_005ffile"><code>gnutls_get_system_config_file</code></a></td><td class="printindex-index-section"><a href="#System_002dwide-configuration-of-the-library">System-wide configuration of the library</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fget_005fsystem_005fconfig_005ffile-1"><code>gnutls_get_system_config_file</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fglobal_005fdeinit"><code>gnutls_global_deinit</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fglobal_005finit"><code>gnutls_global_init</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fglobal_005fset_005faudit_005flog_005ffunction"><code>gnutls_global_set_audit_log_function</code></a></td><td class="printindex-index-section"><a href="#Debugging-and-auditing">Debugging and auditing</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fglobal_005fset_005faudit_005flog_005ffunction-1"><code>gnutls_global_set_audit_log_function</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fglobal_005fset_005flog_005ffunction"><code>gnutls_global_set_log_function</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fglobal_005fset_005flog_005flevel"><code>gnutls_global_set_log_level</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fglobal_005fset_005fmem_005ffunctions"><code>gnutls_global_set_mem_functions</code></a></td><td class="printindex-index-section"><a href="#Compatibility-API">Compatibility API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fglobal_005fset_005fmutex"><code>gnutls_global_set_mutex</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fglobal_005fset_005ftime_005ffunction"><code>gnutls_global_set_time_function</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fgost_005fparamset_005fget_005fname"><code>gnutls_gost_paramset_get_name</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fgost_005fparamset_005fget_005foid"><code>gnutls_gost_paramset_get_oid</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fgroup_005fget"><code>gnutls_group_get</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fgroup_005fget_005fid"><code>gnutls_group_get_id</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fgroup_005fget_005fname"><code>gnutls_group_get_name</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fgroup_005flist"><code>gnutls_group_list</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fhandshake"><code>gnutls_handshake</code></a></td><td class="printindex-index-section"><a href="#TLS-handshake">TLS handshake</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fhandshake-1"><code>gnutls_handshake</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fhandshake_005fdescription_005fget_005fname"><code>gnutls_handshake_description_get_name</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fhandshake_005fget_005flast_005fin"><code>gnutls_handshake_get_last_in</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fhandshake_005fget_005flast_005fout"><code>gnutls_handshake_get_last_out</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fhandshake_005fset_005fhook_005ffunction"><code>gnutls_handshake_set_hook_function</code></a></td><td class="printindex-index-section"><a href="#Virtual-hosts-and-credentials">Virtual hosts and credentials</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fhandshake_005fset_005fhook_005ffunction-1"><code>gnutls_handshake_set_hook_function</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fhandshake_005fset_005fmax_005fpacket_005flength"><code>gnutls_handshake_set_max_packet_length</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fhandshake_005fset_005fpost_005fclient_005fhello_005ffunction"><code>gnutls_handshake_set_post_client_hello_function</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fhandshake_005fset_005fprivate_005fextensions"><code>gnutls_handshake_set_private_extensions</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fhandshake_005fset_005frandom"><code>gnutls_handshake_set_random</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fhandshake_005fset_005fread_005ffunction"><code>gnutls_handshake_set_read_function</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fhandshake_005fset_005fsecret_005ffunction"><code>gnutls_handshake_set_secret_function</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fhandshake_005fset_005ftimeout"><code>gnutls_handshake_set_timeout</code></a></td><td class="printindex-index-section"><a href="#TLS-handshake">TLS handshake</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fhandshake_005fset_005ftimeout-1"><code>gnutls_handshake_set_timeout</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fhandshake_005fupdate_005freceiving_005fkey"><code>gnutls_handshake_update_receiving_key</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fhandshake_005fwrite"><code>gnutls_handshake_write</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fhash"><code>gnutls_hash</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fhash_005fcopy"><code>gnutls_hash_copy</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fhash_005fdeinit"><code>gnutls_hash_deinit</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fhash_005ffast"><code>gnutls_hash_fast</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fhash_005fget_005flen"><code>gnutls_hash_get_len</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fhash_005finit"><code>gnutls_hash_init</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fhash_005foutput"><code>gnutls_hash_output</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fhash_005fsqueeze"><code>gnutls_hash_squeeze</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fheartbeat_005fallowed"><code>gnutls_heartbeat_allowed</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fheartbeat_005fenable"><code>gnutls_heartbeat_enable</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fheartbeat_005fget_005ftimeout"><code>gnutls_heartbeat_get_timeout</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fheartbeat_005fping"><code>gnutls_heartbeat_ping</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fheartbeat_005fpong"><code>gnutls_heartbeat_pong</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fheartbeat_005fset_005ftimeouts"><code>gnutls_heartbeat_set_timeouts</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fhex_005fdecode"><code>gnutls_hex_decode</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fhex_005fdecode2"><code>gnutls_hex_decode2</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fhex_005fencode"><code>gnutls_hex_encode</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fhex_005fencode2"><code>gnutls_hex_encode2</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fhex2bin"><code>gnutls_hex2bin</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fhkdf_005fexpand"><code>gnutls_hkdf_expand</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fhkdf_005fextract"><code>gnutls_hkdf_extract</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fhmac"><code>gnutls_hmac</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fhmac_005fcopy"><code>gnutls_hmac_copy</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fhmac_005fdeinit"><code>gnutls_hmac_deinit</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fhmac_005ffast"><code>gnutls_hmac_fast</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fhmac_005fget_005fkey_005fsize"><code>gnutls_hmac_get_key_size</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fhmac_005fget_005flen"><code>gnutls_hmac_get_len</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fhmac_005finit"><code>gnutls_hmac_init</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fhmac_005foutput"><code>gnutls_hmac_output</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fhmac_005fset_005fnonce"><code>gnutls_hmac_set_nonce</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fidna_005fmap"><code>gnutls_idna_map</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fidna_005freverse_005fmap"><code>gnutls_idna_reverse_map</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005finit"><code>gnutls_init</code></a></td><td class="printindex-index-section"><a href="#Session-initialization">Session initialization</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005finit-1"><code>gnutls_init</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fkey_005fgenerate"><code>gnutls_key_generate</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fkx_005fget"><code>gnutls_kx_get</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fkx_005fget_005fid"><code>gnutls_kx_get_id</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fkx_005fget_005fname"><code>gnutls_kx_get_name</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fkx_005flist"><code>gnutls_kx_list</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fload_005ffile"><code>gnutls_load_file</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fmac_005fget"><code>gnutls_mac_get</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fmac_005fget_005fid"><code>gnutls_mac_get_id</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fmac_005fget_005fkey_005fsize"><code>gnutls_mac_get_key_size</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fmac_005fget_005fname"><code>gnutls_mac_get_name</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fmac_005fget_005fnonce_005fsize"><code>gnutls_mac_get_nonce_size</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fmac_005flist"><code>gnutls_mac_list</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fmemcmp"><code>gnutls_memcmp</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fmemset"><code>gnutls_memset</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005freq_005fadd_005fcert"><code>gnutls_ocsp_req_add_cert</code></a></td><td class="printindex-index-section"><a href="#OCSP-API">OCSP API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005freq_005fadd_005fcert_005fid"><code>gnutls_ocsp_req_add_cert_id</code></a></td><td class="printindex-index-section"><a href="#OCSP-API">OCSP API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005freq_005fdeinit"><code>gnutls_ocsp_req_deinit</code></a></td><td class="printindex-index-section"><a href="#OCSP-API">OCSP API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005freq_005fexport"><code>gnutls_ocsp_req_export</code></a></td><td class="printindex-index-section"><a href="#OCSP-API">OCSP API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005freq_005fget_005fcert_005fid"><code>gnutls_ocsp_req_get_cert_id</code></a></td><td class="printindex-index-section"><a href="#OCSP-API">OCSP API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005freq_005fget_005fextension"><code>gnutls_ocsp_req_get_extension</code></a></td><td class="printindex-index-section"><a href="#OCSP-API">OCSP API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005freq_005fget_005fnonce"><code>gnutls_ocsp_req_get_nonce</code></a></td><td class="printindex-index-section"><a href="#OCSP-API">OCSP API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005freq_005fget_005fversion"><code>gnutls_ocsp_req_get_version</code></a></td><td class="printindex-index-section"><a href="#OCSP-API">OCSP API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005freq_005fimport"><code>gnutls_ocsp_req_import</code></a></td><td class="printindex-index-section"><a href="#OCSP-API">OCSP API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005freq_005finit"><code>gnutls_ocsp_req_init</code></a></td><td class="printindex-index-section"><a href="#OCSP-API">OCSP API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005freq_005fprint"><code>gnutls_ocsp_req_print</code></a></td><td class="printindex-index-section"><a href="#OCSP-API">OCSP API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005freq_005frandomize_005fnonce"><code>gnutls_ocsp_req_randomize_nonce</code></a></td><td class="printindex-index-section"><a href="#OCSP-API">OCSP API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005freq_005fset_005fextension"><code>gnutls_ocsp_req_set_extension</code></a></td><td class="printindex-index-section"><a href="#OCSP-API">OCSP API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005freq_005fset_005fnonce"><code>gnutls_ocsp_req_set_nonce</code></a></td><td class="printindex-index-section"><a href="#OCSP-API">OCSP API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005fresp_005fcheck_005fcrt"><code>gnutls_ocsp_resp_check_crt</code></a></td><td class="printindex-index-section"><a href="#OCSP-API">OCSP API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005fresp_005fdeinit"><code>gnutls_ocsp_resp_deinit</code></a></td><td class="printindex-index-section"><a href="#OCSP-API">OCSP API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005fresp_005fexport"><code>gnutls_ocsp_resp_export</code></a></td><td class="printindex-index-section"><a href="#OCSP-API">OCSP API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005fresp_005fexport2"><code>gnutls_ocsp_resp_export2</code></a></td><td class="printindex-index-section"><a href="#OCSP-API">OCSP API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005fresp_005fget_005fcerts"><code>gnutls_ocsp_resp_get_certs</code></a></td><td class="printindex-index-section"><a href="#OCSP-API">OCSP API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005fresp_005fget_005fextension"><code>gnutls_ocsp_resp_get_extension</code></a></td><td class="printindex-index-section"><a href="#OCSP-API">OCSP API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005fresp_005fget_005fnonce"><code>gnutls_ocsp_resp_get_nonce</code></a></td><td class="printindex-index-section"><a href="#OCSP-API">OCSP API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005fresp_005fget_005fproduced"><code>gnutls_ocsp_resp_get_produced</code></a></td><td class="printindex-index-section"><a href="#OCSP-API">OCSP API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005fresp_005fget_005fresponder"><code>gnutls_ocsp_resp_get_responder</code></a></td><td class="printindex-index-section"><a href="#OCSP-API">OCSP API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005fresp_005fget_005fresponder_005fraw_005fid"><code>gnutls_ocsp_resp_get_responder_raw_id</code></a></td><td class="printindex-index-section"><a href="#OCSP-API">OCSP API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005fresp_005fget_005fresponder2"><code>gnutls_ocsp_resp_get_responder2</code></a></td><td class="printindex-index-section"><a href="#OCSP-API">OCSP API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005fresp_005fget_005fresponse"><code>gnutls_ocsp_resp_get_response</code></a></td><td class="printindex-index-section"><a href="#OCSP-API">OCSP API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005fresp_005fget_005fsignature"><code>gnutls_ocsp_resp_get_signature</code></a></td><td class="printindex-index-section"><a href="#OCSP-API">OCSP API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005fresp_005fget_005fsignature_005falgorithm"><code>gnutls_ocsp_resp_get_signature_algorithm</code></a></td><td class="printindex-index-section"><a href="#OCSP-API">OCSP API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005fresp_005fget_005fsingle"><code>gnutls_ocsp_resp_get_single</code></a></td><td class="printindex-index-section"><a href="#OCSP-certificate-status-checking">OCSP certificate status checking</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005fresp_005fget_005fsingle-1"><code>gnutls_ocsp_resp_get_single</code></a></td><td class="printindex-index-section"><a href="#OCSP-API">OCSP API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005fresp_005fget_005fstatus"><code>gnutls_ocsp_resp_get_status</code></a></td><td class="printindex-index-section"><a href="#OCSP-API">OCSP API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005fresp_005fget_005fversion"><code>gnutls_ocsp_resp_get_version</code></a></td><td class="printindex-index-section"><a href="#OCSP-API">OCSP API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005fresp_005fimport"><code>gnutls_ocsp_resp_import</code></a></td><td class="printindex-index-section"><a href="#OCSP-API">OCSP API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005fresp_005fimport2"><code>gnutls_ocsp_resp_import2</code></a></td><td class="printindex-index-section"><a href="#OCSP-API">OCSP API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005fresp_005finit"><code>gnutls_ocsp_resp_init</code></a></td><td class="printindex-index-section"><a href="#OCSP-API">OCSP API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005fresp_005flist_005fimport2"><code>gnutls_ocsp_resp_list_import2</code></a></td><td class="printindex-index-section"><a href="#OCSP-API">OCSP API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005fresp_005fprint"><code>gnutls_ocsp_resp_print</code></a></td><td class="printindex-index-section"><a href="#OCSP-API">OCSP API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005fresp_005fverify"><code>gnutls_ocsp_resp_verify</code></a></td><td class="printindex-index-section"><a href="#OCSP-API">OCSP API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005fresp_005fverify_005fdirect"><code>gnutls_ocsp_resp_verify_direct</code></a></td><td class="printindex-index-section"><a href="#OCSP-API">OCSP API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005fstatus_005frequest_005fenable_005fclient"><code>gnutls_ocsp_status_request_enable_client</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005fstatus_005frequest_005fget"><code>gnutls_ocsp_status_request_get</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005fstatus_005frequest_005fget2"><code>gnutls_ocsp_status_request_get2</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005focsp_005fstatus_005frequest_005fis_005fchecked"><code>gnutls_ocsp_status_request_is_checked</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005foid_005fto_005fdigest"><code>gnutls_oid_to_digest</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005foid_005fto_005fecc_005fcurve"><code>gnutls_oid_to_ecc_curve</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005foid_005fto_005fgost_005fparamset"><code>gnutls_oid_to_gost_paramset</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005foid_005fto_005fmac"><code>gnutls_oid_to_mac</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005foid_005fto_005fpk"><code>gnutls_oid_to_pk</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005foid_005fto_005fsign"><code>gnutls_oid_to_sign</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fopenpgp_005fprivkey_005fsign_005fhash"><code>gnutls_openpgp_privkey_sign_hash</code></a></td><td class="printindex-index-section"><a href="#Compatibility-API">Compatibility API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fopenpgp_005fsend_005fcert"><code>gnutls_openpgp_send_cert</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpacket_005fdeinit"><code>gnutls_packet_deinit</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpacket_005fget"><code>gnutls_packet_get</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpbkdf2"><code>gnutls_pbkdf2</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpcert_005fdeinit"><code>gnutls_pcert_deinit</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpcert_005fexport_005fopenpgp"><code>gnutls_pcert_export_openpgp</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpcert_005fexport_005fx509"><code>gnutls_pcert_export_x509</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpcert_005fimport_005fopenpgp"><code>gnutls_pcert_import_openpgp</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpcert_005fimport_005fopenpgp_005fraw"><code>gnutls_pcert_import_openpgp_raw</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpcert_005fimport_005frawpk"><code>gnutls_pcert_import_rawpk</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpcert_005fimport_005frawpk_005fraw"><code>gnutls_pcert_import_rawpk_raw</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpcert_005fimport_005fx509"><code>gnutls_pcert_import_x509</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpcert_005fimport_005fx509_005flist"><code>gnutls_pcert_import_x509_list</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpcert_005fimport_005fx509_005fraw"><code>gnutls_pcert_import_x509_raw</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpcert_005flist_005fimport_005fx509_005ffile"><code>gnutls_pcert_list_import_x509_file</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpcert_005flist_005fimport_005fx509_005fraw"><code>gnutls_pcert_list_import_x509_raw</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpem_005fbase64_005fdecode"><code>gnutls_pem_base64_decode</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpem_005fbase64_005fdecode2"><code>gnutls_pem_base64_decode2</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpem_005fbase64_005fencode"><code>gnutls_pem_base64_encode</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpem_005fbase64_005fencode2"><code>gnutls_pem_base64_encode2</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fperror"><code>gnutls_perror</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpk_005falgorithm_005fget_005fname"><code>gnutls_pk_algorithm_get_name</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpk_005fbits_005fto_005fsec_005fparam"><code>gnutls_pk_bits_to_sec_param</code></a></td><td class="printindex-index-section"><a href="#Selecting-cryptographic-key-sizes">Selecting cryptographic key sizes</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpk_005fbits_005fto_005fsec_005fparam-1"><code>gnutls_pk_bits_to_sec_param</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpk_005fget_005fid"><code>gnutls_pk_get_id</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpk_005fget_005fname"><code>gnutls_pk_get_name</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpk_005fget_005foid"><code>gnutls_pk_get_oid</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpk_005flist"><code>gnutls_pk_list</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpk_005fto_005fsign"><code>gnutls_pk_to_sign</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs_005fschema_005fget_005fname"><code>gnutls_pkcs_schema_get_name</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs_005fschema_005fget_005foid"><code>gnutls_pkcs_schema_get_oid</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fadd_005fprovider"><code>gnutls_pkcs11_add_provider</code></a></td><td class="printindex-index-section"><a href="#PKCS11-Manual-Initialization">PKCS11 Manual Initialization</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fadd_005fprovider-1"><code>gnutls_pkcs11_add_provider</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fcopy_005fattached_005fextension"><code>gnutls_pkcs11_copy_attached_extension</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fcopy_005fpubkey"><code>gnutls_pkcs11_copy_pubkey</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fcopy_005fsecret_005fkey"><code>gnutls_pkcs11_copy_secret_key</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fcopy_005fx509_005fcrt"><code>gnutls_pkcs11_copy_x509_crt</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fcopy_005fx509_005fcrt2"><code>gnutls_pkcs11_copy_x509_crt2</code></a></td><td class="printindex-index-section"><a href="#Writing-objects">Writing objects</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fcopy_005fx509_005fcrt2-1"><code>gnutls_pkcs11_copy_x509_crt2</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fcopy_005fx509_005fprivkey"><code>gnutls_pkcs11_copy_x509_privkey</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fcopy_005fx509_005fprivkey2"><code>gnutls_pkcs11_copy_x509_privkey2</code></a></td><td class="printindex-index-section"><a href="#Writing-objects">Writing objects</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fcopy_005fx509_005fprivkey2-1"><code>gnutls_pkcs11_copy_x509_privkey2</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fcrt_005fis_005fknown"><code>gnutls_pkcs11_crt_is_known</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fdeinit"><code>gnutls_pkcs11_deinit</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fdelete_005furl"><code>gnutls_pkcs11_delete_url</code></a></td><td class="printindex-index-section"><a href="#Writing-objects">Writing objects</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fdelete_005furl-1"><code>gnutls_pkcs11_delete_url</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fget_005fpin_005ffunction"><code>gnutls_pkcs11_get_pin_function</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fget_005fraw_005fissuer"><code>gnutls_pkcs11_get_raw_issuer</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fget_005fraw_005fissuer_005fby_005fdn"><code>gnutls_pkcs11_get_raw_issuer_by_dn</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fget_005fraw_005fissuer_005fby_005fsubject_005fkey_005fid"><code>gnutls_pkcs11_get_raw_issuer_by_subject_key_id</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005finit"><code>gnutls_pkcs11_init</code></a></td><td class="printindex-index-section"><a href="#PKCS11-Manual-Initialization">PKCS11 Manual Initialization</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005finit-1"><code>gnutls_pkcs11_init</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fobj_005fdeinit"><code>gnutls_pkcs11_obj_deinit</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fobj_005fexport"><code>gnutls_pkcs11_obj_export</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fobj_005fexport_005furl"><code>gnutls_pkcs11_obj_export_url</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fobj_005fexport2"><code>gnutls_pkcs11_obj_export2</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fobj_005fexport3"><code>gnutls_pkcs11_obj_export3</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fobj_005fflags_005fget_005fstr"><code>gnutls_pkcs11_obj_flags_get_str</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fobj_005fget_005fexts"><code>gnutls_pkcs11_obj_get_exts</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fobj_005fget_005fflags"><code>gnutls_pkcs11_obj_get_flags</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fobj_005fget_005finfo"><code>gnutls_pkcs11_obj_get_info</code></a></td><td class="printindex-index-section"><a href="#Reading-objects">Reading objects</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fobj_005fget_005finfo-1"><code>gnutls_pkcs11_obj_get_info</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fobj_005fget_005fptr"><code>gnutls_pkcs11_obj_get_ptr</code></a></td><td class="printindex-index-section"><a href="#PKCS11-Low-Level-Access">PKCS11 Low Level Access</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fobj_005fget_005fptr-1"><code>gnutls_pkcs11_obj_get_ptr</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fobj_005fget_005ftype"><code>gnutls_pkcs11_obj_get_type</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fobj_005fimport_005furl"><code>gnutls_pkcs11_obj_import_url</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fobj_005finit"><code>gnutls_pkcs11_obj_init</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fobj_005flist_005fimport_005furl3"><code>gnutls_pkcs11_obj_list_import_url3</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fobj_005flist_005fimport_005furl4"><code>gnutls_pkcs11_obj_list_import_url4</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fobj_005fset_005finfo"><code>gnutls_pkcs11_obj_set_info</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fobj_005fset_005fpin_005ffunction"><code>gnutls_pkcs11_obj_set_pin_function</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fprivkey_005fcpy"><code>gnutls_pkcs11_privkey_cpy</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fprivkey_005fdeinit"><code>gnutls_pkcs11_privkey_deinit</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fprivkey_005fexport_005fpubkey"><code>gnutls_pkcs11_privkey_export_pubkey</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fprivkey_005fexport_005furl"><code>gnutls_pkcs11_privkey_export_url</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fprivkey_005fgenerate"><code>gnutls_pkcs11_privkey_generate</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fprivkey_005fgenerate2"><code>gnutls_pkcs11_privkey_generate2</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fprivkey_005fgenerate3"><code>gnutls_pkcs11_privkey_generate3</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fprivkey_005fget_005finfo"><code>gnutls_pkcs11_privkey_get_info</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fprivkey_005fget_005fpk_005falgorithm"><code>gnutls_pkcs11_privkey_get_pk_algorithm</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fprivkey_005fimport_005furl"><code>gnutls_pkcs11_privkey_import_url</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fprivkey_005finit"><code>gnutls_pkcs11_privkey_init</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fprivkey_005fset_005fpin_005ffunction"><code>gnutls_pkcs11_privkey_set_pin_function</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fprivkey_005fstatus"><code>gnutls_pkcs11_privkey_status</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005freinit"><code>gnutls_pkcs11_reinit</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fset_005fpin_005ffunction"><code>gnutls_pkcs11_set_pin_function</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005fset_005ftoken_005ffunction"><code>gnutls_pkcs11_set_token_function</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005ftoken_005fcheck_005fmechanism"><code>gnutls_pkcs11_token_check_mechanism</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005ftoken_005fget_005fflags"><code>gnutls_pkcs11_token_get_flags</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005ftoken_005fget_005finfo"><code>gnutls_pkcs11_token_get_info</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005ftoken_005fget_005fmechanism"><code>gnutls_pkcs11_token_get_mechanism</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005ftoken_005fget_005fptr"><code>gnutls_pkcs11_token_get_ptr</code></a></td><td class="printindex-index-section"><a href="#PKCS11-Low-Level-Access">PKCS11 Low Level Access</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005ftoken_005fget_005fptr-1"><code>gnutls_pkcs11_token_get_ptr</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005ftoken_005fget_005frandom"><code>gnutls_pkcs11_token_get_random</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005ftoken_005fget_005furl"><code>gnutls_pkcs11_token_get_url</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005ftoken_005finit"><code>gnutls_pkcs11_token_init</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005ftoken_005fset_005fpin"><code>gnutls_pkcs11_token_set_pin</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs11_005ftype_005fget_005fname"><code>gnutls_pkcs11_type_get_name</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs12_005fbag_005fdecrypt"><code>gnutls_pkcs12_bag_decrypt</code></a></td><td class="printindex-index-section"><a href="#PKCS-12-API">PKCS 12 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs12_005fbag_005fdeinit"><code>gnutls_pkcs12_bag_deinit</code></a></td><td class="printindex-index-section"><a href="#PKCS-12-API">PKCS 12 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs12_005fbag_005fenc_005finfo"><code>gnutls_pkcs12_bag_enc_info</code></a></td><td class="printindex-index-section"><a href="#PKCS-12-API">PKCS 12 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs12_005fbag_005fencrypt"><code>gnutls_pkcs12_bag_encrypt</code></a></td><td class="printindex-index-section"><a href="#PKCS-12-API">PKCS 12 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs12_005fbag_005fget_005fcount"><code>gnutls_pkcs12_bag_get_count</code></a></td><td class="printindex-index-section"><a href="#PKCS-12-API">PKCS 12 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs12_005fbag_005fget_005fdata"><code>gnutls_pkcs12_bag_get_data</code></a></td><td class="printindex-index-section"><a href="#PKCS-12-API">PKCS 12 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs12_005fbag_005fget_005ffriendly_005fname"><code>gnutls_pkcs12_bag_get_friendly_name</code></a></td><td class="printindex-index-section"><a href="#PKCS-12-API">PKCS 12 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs12_005fbag_005fget_005fkey_005fid"><code>gnutls_pkcs12_bag_get_key_id</code></a></td><td class="printindex-index-section"><a href="#PKCS-12-API">PKCS 12 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs12_005fbag_005fget_005ftype"><code>gnutls_pkcs12_bag_get_type</code></a></td><td class="printindex-index-section"><a href="#PKCS-12-API">PKCS 12 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs12_005fbag_005finit"><code>gnutls_pkcs12_bag_init</code></a></td><td class="printindex-index-section"><a href="#PKCS-12-API">PKCS 12 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs12_005fbag_005fset_005fcrl"><code>gnutls_pkcs12_bag_set_crl</code></a></td><td class="printindex-index-section"><a href="#PKCS-12-API">PKCS 12 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs12_005fbag_005fset_005fcrt"><code>gnutls_pkcs12_bag_set_crt</code></a></td><td class="printindex-index-section"><a href="#PKCS-12-API">PKCS 12 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs12_005fbag_005fset_005fdata"><code>gnutls_pkcs12_bag_set_data</code></a></td><td class="printindex-index-section"><a href="#PKCS-12-API">PKCS 12 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs12_005fbag_005fset_005ffriendly_005fname"><code>gnutls_pkcs12_bag_set_friendly_name</code></a></td><td class="printindex-index-section"><a href="#PKCS-12-API">PKCS 12 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs12_005fbag_005fset_005fkey_005fid"><code>gnutls_pkcs12_bag_set_key_id</code></a></td><td class="printindex-index-section"><a href="#PKCS-12-API">PKCS 12 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs12_005fbag_005fset_005fprivkey"><code>gnutls_pkcs12_bag_set_privkey</code></a></td><td class="printindex-index-section"><a href="#PKCS-12-API">PKCS 12 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs12_005fdeinit"><code>gnutls_pkcs12_deinit</code></a></td><td class="printindex-index-section"><a href="#PKCS-12-API">PKCS 12 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs12_005fexport"><code>gnutls_pkcs12_export</code></a></td><td class="printindex-index-section"><a href="#PKCS-12-API">PKCS 12 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs12_005fexport2"><code>gnutls_pkcs12_export2</code></a></td><td class="printindex-index-section"><a href="#PKCS-12-API">PKCS 12 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs12_005fgenerate_005fmac"><code>gnutls_pkcs12_generate_mac</code></a></td><td class="printindex-index-section"><a href="#PKCS-12-API">PKCS 12 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs12_005fgenerate_005fmac2"><code>gnutls_pkcs12_generate_mac2</code></a></td><td class="printindex-index-section"><a href="#PKCS-12-API">PKCS 12 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs12_005fgenerate_005fmac3"><code>gnutls_pkcs12_generate_mac3</code></a></td><td class="printindex-index-section"><a href="#PKCS-12-API">PKCS 12 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs12_005fget_005fbag"><code>gnutls_pkcs12_get_bag</code></a></td><td class="printindex-index-section"><a href="#PKCS-12-API">PKCS 12 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs12_005fimport"><code>gnutls_pkcs12_import</code></a></td><td class="printindex-index-section"><a href="#PKCS-12-API">PKCS 12 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs12_005finit"><code>gnutls_pkcs12_init</code></a></td><td class="printindex-index-section"><a href="#PKCS-12-API">PKCS 12 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs12_005fmac_005finfo"><code>gnutls_pkcs12_mac_info</code></a></td><td class="printindex-index-section"><a href="#PKCS-12-API">PKCS 12 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs12_005fset_005fbag"><code>gnutls_pkcs12_set_bag</code></a></td><td class="printindex-index-section"><a href="#PKCS-12-API">PKCS 12 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs12_005fsimple_005fparse"><code>gnutls_pkcs12_simple_parse</code></a></td><td class="printindex-index-section"><a href="#Managing-encrypted-keys">Managing encrypted keys</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs12_005fsimple_005fparse-1"><code>gnutls_pkcs12_simple_parse</code></a></td><td class="printindex-index-section"><a href="#PKCS-12-API">PKCS 12 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs12_005fverify_005fmac"><code>gnutls_pkcs12_verify_mac</code></a></td><td class="printindex-index-section"><a href="#PKCS-12-API">PKCS 12 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs7_005fadd_005fattr"><code>gnutls_pkcs7_add_attr</code></a></td><td class="printindex-index-section"><a href="#PKCS-7-API">PKCS 7 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs7_005fattrs_005fdeinit"><code>gnutls_pkcs7_attrs_deinit</code></a></td><td class="printindex-index-section"><a href="#PKCS-7-API">PKCS 7 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs7_005fdeinit"><code>gnutls_pkcs7_deinit</code></a></td><td class="printindex-index-section"><a href="#PKCS-7-API">PKCS 7 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs7_005fdelete_005fcrl"><code>gnutls_pkcs7_delete_crl</code></a></td><td class="printindex-index-section"><a href="#PKCS-7-API">PKCS 7 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs7_005fdelete_005fcrt"><code>gnutls_pkcs7_delete_crt</code></a></td><td class="printindex-index-section"><a href="#PKCS-7-API">PKCS 7 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs7_005fexport"><code>gnutls_pkcs7_export</code></a></td><td class="printindex-index-section"><a href="#PKCS-7-API">PKCS 7 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs7_005fexport2"><code>gnutls_pkcs7_export2</code></a></td><td class="printindex-index-section"><a href="#PKCS-7-API">PKCS 7 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs7_005fget_005fattr"><code>gnutls_pkcs7_get_attr</code></a></td><td class="printindex-index-section"><a href="#PKCS-7-API">PKCS 7 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs7_005fget_005fcrl_005fcount"><code>gnutls_pkcs7_get_crl_count</code></a></td><td class="printindex-index-section"><a href="#PKCS-7-API">PKCS 7 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs7_005fget_005fcrl_005fraw"><code>gnutls_pkcs7_get_crl_raw</code></a></td><td class="printindex-index-section"><a href="#PKCS-7-API">PKCS 7 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs7_005fget_005fcrl_005fraw2"><code>gnutls_pkcs7_get_crl_raw2</code></a></td><td class="printindex-index-section"><a href="#PKCS-7-API">PKCS 7 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs7_005fget_005fcrt_005fcount"><code>gnutls_pkcs7_get_crt_count</code></a></td><td class="printindex-index-section"><a href="#PKCS-7-API">PKCS 7 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs7_005fget_005fcrt_005fraw"><code>gnutls_pkcs7_get_crt_raw</code></a></td><td class="printindex-index-section"><a href="#PKCS-7-API">PKCS 7 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs7_005fget_005fcrt_005fraw2"><code>gnutls_pkcs7_get_crt_raw2</code></a></td><td class="printindex-index-section"><a href="#PKCS-7-API">PKCS 7 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs7_005fget_005fembedded_005fdata"><code>gnutls_pkcs7_get_embedded_data</code></a></td><td class="printindex-index-section"><a href="#PKCS-7-API">PKCS 7 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs7_005fget_005fembedded_005fdata_005foid"><code>gnutls_pkcs7_get_embedded_data_oid</code></a></td><td class="printindex-index-section"><a href="#PKCS-7-API">PKCS 7 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs7_005fget_005fsignature_005fcount"><code>gnutls_pkcs7_get_signature_count</code></a></td><td class="printindex-index-section"><a href="#PKCS-7-API">PKCS 7 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs7_005fget_005fsignature_005finfo"><code>gnutls_pkcs7_get_signature_info</code></a></td><td class="printindex-index-section"><a href="#PKCS-7-API">PKCS 7 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs7_005fimport"><code>gnutls_pkcs7_import</code></a></td><td class="printindex-index-section"><a href="#PKCS-7-API">PKCS 7 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs7_005finit"><code>gnutls_pkcs7_init</code></a></td><td class="printindex-index-section"><a href="#PKCS-7-API">PKCS 7 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs7_005fprint"><code>gnutls_pkcs7_print</code></a></td><td class="printindex-index-section"><a href="#PKCS-7-API">PKCS 7 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs7_005fprint_005fsignature_005finfo"><code>gnutls_pkcs7_print_signature_info</code></a></td><td class="printindex-index-section"><a href="#PKCS-7-API">PKCS 7 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs7_005fset_005fcrl"><code>gnutls_pkcs7_set_crl</code></a></td><td class="printindex-index-section"><a href="#PKCS-7-API">PKCS 7 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs7_005fset_005fcrl_005fraw"><code>gnutls_pkcs7_set_crl_raw</code></a></td><td class="printindex-index-section"><a href="#PKCS-7-API">PKCS 7 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs7_005fset_005fcrt"><code>gnutls_pkcs7_set_crt</code></a></td><td class="printindex-index-section"><a href="#PKCS-7-API">PKCS 7 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs7_005fset_005fcrt_005fraw"><code>gnutls_pkcs7_set_crt_raw</code></a></td><td class="printindex-index-section"><a href="#PKCS-7-API">PKCS 7 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs7_005fsign"><code>gnutls_pkcs7_sign</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-Message-Syntax-_002f-PKCS7">Cryptographic Message Syntax / PKCS7</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs7_005fsign-1"><code>gnutls_pkcs7_sign</code></a></td><td class="printindex-index-section"><a href="#PKCS-7-API">PKCS 7 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs7_005fsignature_005finfo_005fdeinit"><code>gnutls_pkcs7_signature_info_deinit</code></a></td><td class="printindex-index-section"><a href="#PKCS-7-API">PKCS 7 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs7_005fverify"><code>gnutls_pkcs7_verify</code></a></td><td class="printindex-index-section"><a href="#PKCS-7-API">PKCS 7 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs7_005fverify_005fdirect"><code>gnutls_pkcs7_verify_direct</code></a></td><td class="printindex-index-section"><a href="#PKCS-7-API">PKCS 7 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpkcs8_005finfo"><code>gnutls_pkcs8_info</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprf"><code>gnutls_prf</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprf_005fearly"><code>gnutls_prf_early</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprf_005fhash_005fget"><code>gnutls_prf_hash_get</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprf_005fraw"><code>gnutls_prf_raw</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprf_005frfc5705"><code>gnutls_prf_rfc5705</code></a></td><td class="printindex-index-section"><a href="#Deriving-keys-for-other-applications_002fprotocols">Deriving keys for other applications/protocols</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprf_005frfc5705-1"><code>gnutls_prf_rfc5705</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpriority_005fcertificate_005ftype_005flist"><code>gnutls_priority_certificate_type_list</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpriority_005fcertificate_005ftype_005flist2"><code>gnutls_priority_certificate_type_list2</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpriority_005fcipher_005flist"><code>gnutls_priority_cipher_list</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpriority_005fcompression_005flist"><code>gnutls_priority_compression_list</code></a></td><td class="printindex-index-section"><a href="#Compatibility-API">Compatibility API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpriority_005fdeinit"><code>gnutls_priority_deinit</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpriority_005fecc_005fcurve_005flist"><code>gnutls_priority_ecc_curve_list</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpriority_005fget_005fcipher_005fsuite_005findex"><code>gnutls_priority_get_cipher_suite_index</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpriority_005fgroup_005flist"><code>gnutls_priority_group_list</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpriority_005finit"><code>gnutls_priority_init</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpriority_005finit2"><code>gnutls_priority_init2</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpriority_005fkx_005flist"><code>gnutls_priority_kx_list</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpriority_005fmac_005flist"><code>gnutls_priority_mac_list</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpriority_005fprotocol_005flist"><code>gnutls_priority_protocol_list</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpriority_005fset"><code>gnutls_priority_set</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpriority_005fset_005fdirect"><code>gnutls_priority_set_direct</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpriority_005fsign_005flist"><code>gnutls_priority_sign_list</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpriority_005fstring_005flist"><code>gnutls_priority_string_list</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fdecrypt_005fdata"><code>gnutls_privkey_decrypt_data</code></a></td><td class="printindex-index-section"><a href="#Operations">Operations</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fdecrypt_005fdata-1"><code>gnutls_privkey_decrypt_data</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fdecrypt_005fdata2"><code>gnutls_privkey_decrypt_data2</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fdeinit"><code>gnutls_privkey_deinit</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fderive_005fsecret"><code>gnutls_privkey_derive_secret</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fexport_005fdh_005fraw"><code>gnutls_privkey_export_dh_raw</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fexport_005fdsa_005fraw"><code>gnutls_privkey_export_dsa_raw</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fexport_005fdsa_005fraw2"><code>gnutls_privkey_export_dsa_raw2</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fexport_005fecc_005fraw"><code>gnutls_privkey_export_ecc_raw</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fexport_005fecc_005fraw2"><code>gnutls_privkey_export_ecc_raw2</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fexport_005fgost_005fraw2"><code>gnutls_privkey_export_gost_raw2</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fexport_005fopenpgp"><code>gnutls_privkey_export_openpgp</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fexport_005fpkcs11"><code>gnutls_privkey_export_pkcs11</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fexport_005frsa_005fraw"><code>gnutls_privkey_export_rsa_raw</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fexport_005frsa_005fraw2"><code>gnutls_privkey_export_rsa_raw2</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fexport_005fx509"><code>gnutls_privkey_export_x509</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fgenerate"><code>gnutls_privkey_generate</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fgenerate2"><code>gnutls_privkey_generate2</code></a></td><td class="printindex-index-section"><a href="#Public-key-algorithms">Public key algorithms</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fgenerate2-1"><code>gnutls_privkey_generate2</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fget_005fpk_005falgorithm"><code>gnutls_privkey_get_pk_algorithm</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fget_005fseed"><code>gnutls_privkey_get_seed</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fget_005fspki"><code>gnutls_privkey_get_spki</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fget_005ftype"><code>gnutls_privkey_get_type</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fimport_005fdh_005fraw"><code>gnutls_privkey_import_dh_raw</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fimport_005fdsa_005fraw"><code>gnutls_privkey_import_dsa_raw</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fimport_005fecc_005fraw"><code>gnutls_privkey_import_ecc_raw</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fimport_005fext"><code>gnutls_privkey_import_ext</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fimport_005fext2"><code>gnutls_privkey_import_ext2</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fimport_005fext3"><code>gnutls_privkey_import_ext3</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fimport_005fext4"><code>gnutls_privkey_import_ext4</code></a></td><td class="printindex-index-section"><a href="#Abstract-private-keys">Abstract private keys</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fimport_005fext4-1"><code>gnutls_privkey_import_ext4</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fimport_005fgost_005fraw"><code>gnutls_privkey_import_gost_raw</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fimport_005fopenpgp"><code>gnutls_privkey_import_openpgp</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fimport_005fopenpgp_005fraw"><code>gnutls_privkey_import_openpgp_raw</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fimport_005fpkcs11"><code>gnutls_privkey_import_pkcs11</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fimport_005fpkcs11_005furl"><code>gnutls_privkey_import_pkcs11_url</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fimport_005frsa_005fraw"><code>gnutls_privkey_import_rsa_raw</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fimport_005ftpm_005fraw"><code>gnutls_privkey_import_tpm_raw</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fimport_005ftpm_005furl"><code>gnutls_privkey_import_tpm_url</code></a></td><td class="printindex-index-section"><a href="#Using-keys">Using keys</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fimport_005ftpm_005furl-1"><code>gnutls_privkey_import_tpm_url</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fimport_005furl"><code>gnutls_privkey_import_url</code></a></td><td class="printindex-index-section"><a href="#Abstract-private-keys">Abstract private keys</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fimport_005furl-1"><code>gnutls_privkey_import_url</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fimport_005fx509"><code>gnutls_privkey_import_x509</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fimport_005fx509_005fraw"><code>gnutls_privkey_import_x509_raw</code></a></td><td class="printindex-index-section"><a href="#Managing-encrypted-keys">Managing encrypted keys</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fimport_005fx509_005fraw-1"><code>gnutls_privkey_import_x509_raw</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005finit"><code>gnutls_privkey_init</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fset_005fflags"><code>gnutls_privkey_set_flags</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fset_005fpin_005ffunction"><code>gnutls_privkey_set_pin_function</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fset_005fspki"><code>gnutls_privkey_set_spki</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fsign_005fdata"><code>gnutls_privkey_sign_data</code></a></td><td class="printindex-index-section"><a href="#Operations">Operations</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fsign_005fdata-1"><code>gnutls_privkey_sign_data</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fsign_005fdata2"><code>gnutls_privkey_sign_data2</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fsign_005fhash"><code>gnutls_privkey_sign_hash</code></a></td><td class="printindex-index-section"><a href="#Operations">Operations</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fsign_005fhash-1"><code>gnutls_privkey_sign_hash</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fsign_005fhash2"><code>gnutls_privkey_sign_hash2</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fstatus"><code>gnutls_privkey_status</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fverify_005fparams"><code>gnutls_privkey_verify_params</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprivkey_005fverify_005fseed"><code>gnutls_privkey_verify_seed</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprotocol_005fget_005fid"><code>gnutls_protocol_get_id</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprotocol_005fget_005fname"><code>gnutls_protocol_get_name</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprotocol_005fget_005fversion"><code>gnutls_protocol_get_version</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprotocol_005flist"><code>gnutls_protocol_list</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fprotocol_005fset_005fenabled"><code>gnutls_protocol_set_enabled</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpsk_005fallocate_005fclient_005fcredentials"><code>gnutls_psk_allocate_client_credentials</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpsk_005fallocate_005fclient_005fcredentials2"><code>gnutls_psk_allocate_client_credentials2</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpsk_005fallocate_005fserver_005fcredentials"><code>gnutls_psk_allocate_server_credentials</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpsk_005fallocate_005fserver_005fcredentials2"><code>gnutls_psk_allocate_server_credentials2</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpsk_005fclient_005fget_005fhint"><code>gnutls_psk_client_get_hint</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpsk_005fformat_005fimported_005fidentity"><code>gnutls_psk_format_imported_identity</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpsk_005ffree_005fclient_005fcredentials"><code>gnutls_psk_free_client_credentials</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpsk_005ffree_005fserver_005fcredentials"><code>gnutls_psk_free_server_credentials</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpsk_005fserver_005fget_005fusername"><code>gnutls_psk_server_get_username</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpsk_005fserver_005fget_005fusername2"><code>gnutls_psk_server_get_username2</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpsk_005fset_005fclient_005fcredentials"><code>gnutls_psk_set_client_credentials</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpsk_005fset_005fclient_005fcredentials_005ffunction"><code>gnutls_psk_set_client_credentials_function</code></a></td><td class="printindex-index-section"><a href="#PSK-credentials">PSK credentials</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpsk_005fset_005fclient_005fcredentials_005ffunction-1"><code>gnutls_psk_set_client_credentials_function</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpsk_005fset_005fclient_005fcredentials_005ffunction2"><code>gnutls_psk_set_client_credentials_function2</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpsk_005fset_005fclient_005fcredentials_005ffunction3"><code>gnutls_psk_set_client_credentials_function3</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpsk_005fset_005fclient_005fcredentials2"><code>gnutls_psk_set_client_credentials2</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpsk_005fset_005fparams_005ffunction"><code>gnutls_psk_set_params_function</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpsk_005fset_005fserver_005fcredentials_005ffile"><code>gnutls_psk_set_server_credentials_file</code></a></td><td class="printindex-index-section"><a href="#PSK-credentials">PSK credentials</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpsk_005fset_005fserver_005fcredentials_005ffile-1"><code>gnutls_psk_set_server_credentials_file</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpsk_005fset_005fserver_005fcredentials_005ffunction"><code>gnutls_psk_set_server_credentials_function</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpsk_005fset_005fserver_005fcredentials_005ffunction2"><code>gnutls_psk_set_server_credentials_function2</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpsk_005fset_005fserver_005fcredentials_005ffunction3"><code>gnutls_psk_set_server_credentials_function3</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpsk_005fset_005fserver_005fcredentials_005fhint"><code>gnutls_psk_set_server_credentials_hint</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpsk_005fset_005fserver_005fdh_005fparams"><code>gnutls_psk_set_server_dh_params</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpsk_005fset_005fserver_005fknown_005fdh_005fparams"><code>gnutls_psk_set_server_known_dh_params</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpsk_005fset_005fserver_005fparams_005ffunction"><code>gnutls_psk_set_server_params_function</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fdeinit"><code>gnutls_pubkey_deinit</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fencrypt_005fdata"><code>gnutls_pubkey_encrypt_data</code></a></td><td class="printindex-index-section"><a href="#Operations">Operations</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fencrypt_005fdata-1"><code>gnutls_pubkey_encrypt_data</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fexport"><code>gnutls_pubkey_export</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fexport_005fdh_005fraw"><code>gnutls_pubkey_export_dh_raw</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fexport_005fdsa_005fraw"><code>gnutls_pubkey_export_dsa_raw</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fexport_005fdsa_005fraw2"><code>gnutls_pubkey_export_dsa_raw2</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fexport_005fecc_005fraw"><code>gnutls_pubkey_export_ecc_raw</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fexport_005fecc_005fraw2"><code>gnutls_pubkey_export_ecc_raw2</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fexport_005fecc_005fx962"><code>gnutls_pubkey_export_ecc_x962</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fexport_005fgost_005fraw2"><code>gnutls_pubkey_export_gost_raw2</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fexport_005frsa_005fraw"><code>gnutls_pubkey_export_rsa_raw</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fexport_005frsa_005fraw2"><code>gnutls_pubkey_export_rsa_raw2</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fexport2"><code>gnutls_pubkey_export2</code></a></td><td class="printindex-index-section"><a href="#Abstract-public-keys">Abstract public keys</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fexport2-1"><code>gnutls_pubkey_export2</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fget_005fkey_005fid"><code>gnutls_pubkey_get_key_id</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fget_005fkey_005fusage"><code>gnutls_pubkey_get_key_usage</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fget_005fopenpgp_005fkey_005fid"><code>gnutls_pubkey_get_openpgp_key_id</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fget_005fpk_005falgorithm"><code>gnutls_pubkey_get_pk_algorithm</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fget_005fpreferred_005fhash_005falgorithm"><code>gnutls_pubkey_get_preferred_hash_algorithm</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fget_005fspki"><code>gnutls_pubkey_get_spki</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fimport"><code>gnutls_pubkey_import</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fimport_005fdh_005fraw"><code>gnutls_pubkey_import_dh_raw</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fimport_005fdsa_005fraw"><code>gnutls_pubkey_import_dsa_raw</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fimport_005fecc_005fraw"><code>gnutls_pubkey_import_ecc_raw</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fimport_005fecc_005fx962"><code>gnutls_pubkey_import_ecc_x962</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fimport_005fgost_005fraw"><code>gnutls_pubkey_import_gost_raw</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fimport_005fopenpgp"><code>gnutls_pubkey_import_openpgp</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fimport_005fopenpgp_005fraw"><code>gnutls_pubkey_import_openpgp_raw</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fimport_005fpkcs11"><code>gnutls_pubkey_import_pkcs11</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fimport_005fprivkey"><code>gnutls_pubkey_import_privkey</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fimport_005frsa_005fraw"><code>gnutls_pubkey_import_rsa_raw</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fimport_005ftpm_005fraw"><code>gnutls_pubkey_import_tpm_raw</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fimport_005ftpm_005furl"><code>gnutls_pubkey_import_tpm_url</code></a></td><td class="printindex-index-section"><a href="#Using-keys">Using keys</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fimport_005ftpm_005furl-1"><code>gnutls_pubkey_import_tpm_url</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fimport_005furl"><code>gnutls_pubkey_import_url</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fimport_005fx509"><code>gnutls_pubkey_import_x509</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fimport_005fx509_005fcrq"><code>gnutls_pubkey_import_x509_crq</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fimport_005fx509_005fraw"><code>gnutls_pubkey_import_x509_raw</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005finit"><code>gnutls_pubkey_init</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fprint"><code>gnutls_pubkey_print</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fset_005fkey_005fusage"><code>gnutls_pubkey_set_key_usage</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fset_005fpin_005ffunction"><code>gnutls_pubkey_set_pin_function</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fset_005fspki"><code>gnutls_pubkey_set_spki</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fverify_005fdata2"><code>gnutls_pubkey_verify_data2</code></a></td><td class="printindex-index-section"><a href="#Operations">Operations</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fverify_005fdata2-1"><code>gnutls_pubkey_verify_data2</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fverify_005fhash2"><code>gnutls_pubkey_verify_hash2</code></a></td><td class="printindex-index-section"><a href="#Operations">Operations</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fverify_005fhash2-1"><code>gnutls_pubkey_verify_hash2</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fpubkey_005fverify_005fparams"><code>gnutls_pubkey_verify_params</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frandom_005fart"><code>gnutls_random_art</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frange_005fsplit"><code>gnutls_range_split</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005freauth"><code>gnutls_reauth</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frecord_005fcan_005fuse_005flength_005fhiding"><code>gnutls_record_can_use_length_hiding</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frecord_005fcheck_005fcorked"><code>gnutls_record_check_corked</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frecord_005fcheck_005fpending"><code>gnutls_record_check_pending</code></a></td><td class="printindex-index-section"><a href="#Data-transfer-and-termination">Data transfer and termination</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frecord_005fcheck_005fpending-1"><code>gnutls_record_check_pending</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frecord_005fcork"><code>gnutls_record_cork</code></a></td><td class="printindex-index-section"><a href="#Buffered-data-transfer">Buffered data transfer</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frecord_005fcork-1"><code>gnutls_record_cork</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frecord_005fdisable_005fpadding"><code>gnutls_record_disable_padding</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frecord_005fdiscard_005fqueued"><code>gnutls_record_discard_queued</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frecord_005fget_005fdirection"><code>gnutls_record_get_direction</code></a></td><td class="printindex-index-section"><a href="#Asynchronous-operation">Asynchronous operation</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frecord_005fget_005fdirection-1"><code>gnutls_record_get_direction</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frecord_005fget_005fdiscarded"><code>gnutls_record_get_discarded</code></a></td><td class="printindex-index-section"><a href="#Datagram-TLS-API">Datagram TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frecord_005fget_005fmax_005fearly_005fdata_005fsize"><code>gnutls_record_get_max_early_data_size</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frecord_005fget_005fmax_005fsend_005fsize"><code>gnutls_record_get_max_send_size</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frecord_005fget_005fmax_005fsize"><code>gnutls_record_get_max_size</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frecord_005fget_005fstate"><code>gnutls_record_get_state</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frecord_005foverhead_005fsize"><code>gnutls_record_overhead_size</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frecord_005frecv"><code>gnutls_record_recv</code></a></td><td class="printindex-index-section"><a href="#Data-transfer-and-termination">Data transfer and termination</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frecord_005frecv-1"><code>gnutls_record_recv</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frecord_005frecv_005fearly_005fdata"><code>gnutls_record_recv_early_data</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frecord_005frecv_005fpacket"><code>gnutls_record_recv_packet</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frecord_005frecv_005fseq"><code>gnutls_record_recv_seq</code></a></td><td class="printindex-index-section"><a href="#Data-transfer-and-termination">Data transfer and termination</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frecord_005frecv_005fseq-1"><code>gnutls_record_recv_seq</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frecord_005fsend"><code>gnutls_record_send</code></a></td><td class="printindex-index-section"><a href="#Data-transfer-and-termination">Data transfer and termination</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frecord_005fsend-1"><code>gnutls_record_send</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frecord_005fsend_005fearly_005fdata"><code>gnutls_record_send_early_data</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frecord_005fsend_005ffile"><code>gnutls_record_send_file</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frecord_005fsend_005frange"><code>gnutls_record_send_range</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frecord_005fsend2"><code>gnutls_record_send2</code></a></td><td class="printindex-index-section"><a href="#On-Record-Padding">On Record Padding</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frecord_005fsend2-1"><code>gnutls_record_send2</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frecord_005fset_005fmax_005fearly_005fdata_005fsize"><code>gnutls_record_set_max_early_data_size</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frecord_005fset_005fmax_005frecv_005fsize"><code>gnutls_record_set_max_recv_size</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frecord_005fset_005fmax_005fsize"><code>gnutls_record_set_max_size</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frecord_005fset_005fstate"><code>gnutls_record_set_state</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frecord_005fset_005ftimeout"><code>gnutls_record_set_timeout</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frecord_005funcork"><code>gnutls_record_uncork</code></a></td><td class="printindex-index-section"><a href="#Buffered-data-transfer">Buffered data transfer</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frecord_005funcork-1"><code>gnutls_record_uncork</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fregister_005fcustom_005furl"><code>gnutls_register_custom_url</code></a></td><td class="printindex-index-section"><a href="#Application_002dspecific-keys">Application-specific keys</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fregister_005fcustom_005furl-1"><code>gnutls_register_custom_url</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frehandshake"><code>gnutls_rehandshake</code></a></td><td class="printindex-index-section"><a href="#TLS-1_002e2-re_002dauthentication">TLS 1.2 re-authentication</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frehandshake-1"><code>gnutls_rehandshake</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frnd"><code>gnutls_rnd</code></a></td><td class="printindex-index-section"><a href="#Random-number-generation">Random number generation</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frnd-1"><code>gnutls_rnd</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005frnd_005frefresh"><code>gnutls_rnd_refresh</code></a></td><td class="printindex-index-section"><a href="#Cryptographic-API">Cryptographic API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsafe_005frenegotiation_005fstatus"><code>gnutls_safe_renegotiation_status</code></a></td><td class="printindex-index-section"><a href="#TLS-1_002e2-re_002dauthentication">TLS 1.2 re-authentication</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsafe_005frenegotiation_005fstatus-1"><code>gnutls_safe_renegotiation_status</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsec_005fparam_005fget_005fname"><code>gnutls_sec_param_get_name</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsec_005fparam_005fto_005fpk_005fbits"><code>gnutls_sec_param_to_pk_bits</code></a></td><td class="printindex-index-section"><a href="#Selecting-cryptographic-key-sizes">Selecting cryptographic key sizes</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsec_005fparam_005fto_005fpk_005fbits-1"><code>gnutls_sec_param_to_pk_bits</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsec_005fparam_005fto_005fsymmetric_005fbits"><code>gnutls_sec_param_to_symmetric_bits</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fserver_005fname_005fget"><code>gnutls_server_name_get</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fserver_005fname_005fset"><code>gnutls_server_name_set</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsession_005fchannel_005fbinding"><code>gnutls_session_channel_binding</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsession_005fenable_005fcompatibility_005fmode"><code>gnutls_session_enable_compatibility_mode</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsession_005fetm_005fstatus"><code>gnutls_session_etm_status</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsession_005fext_005fmaster_005fsecret_005fstatus"><code>gnutls_session_ext_master_secret_status</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsession_005fext_005fregister"><code>gnutls_session_ext_register</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsession_005fforce_005fvalid"><code>gnutls_session_force_valid</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsession_005fget_005fdata"><code>gnutls_session_get_data</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsession_005fget_005fdata2"><code>gnutls_session_get_data2</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsession_005fget_005fdesc"><code>gnutls_session_get_desc</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsession_005fget_005fflags"><code>gnutls_session_get_flags</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsession_005fget_005fid"><code>gnutls_session_get_id</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsession_005fget_005fid2"><code>gnutls_session_get_id2</code></a></td><td class="printindex-index-section"><a href="#Session-resumption">Session resumption</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsession_005fget_005fid2-1"><code>gnutls_session_get_id2</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsession_005fget_005fkeylog_005ffunction"><code>gnutls_session_get_keylog_function</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsession_005fget_005fmaster_005fsecret"><code>gnutls_session_get_master_secret</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsession_005fget_005fptr"><code>gnutls_session_get_ptr</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsession_005fget_005frandom"><code>gnutls_session_get_random</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsession_005fget_005fverify_005fcert_005fstatus"><code>gnutls_session_get_verify_cert_status</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsession_005fis_005fresumed"><code>gnutls_session_is_resumed</code></a></td><td class="printindex-index-section"><a href="#Session-resumption">Session resumption</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsession_005fis_005fresumed-1"><code>gnutls_session_is_resumed</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsession_005fkey_005fupdate"><code>gnutls_session_key_update</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsession_005fresumption_005frequested"><code>gnutls_session_resumption_requested</code></a></td><td class="printindex-index-section"><a href="#Session-resumption">Session resumption</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsession_005fresumption_005frequested-1"><code>gnutls_session_resumption_requested</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsession_005fset_005fdata"><code>gnutls_session_set_data</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsession_005fset_005fid"><code>gnutls_session_set_id</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsession_005fset_005fkeylog_005ffunction"><code>gnutls_session_set_keylog_function</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsession_005fset_005fpremaster"><code>gnutls_session_set_premaster</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsession_005fset_005fptr"><code>gnutls_session_set_ptr</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsession_005fset_005fverify_005fcert"><code>gnutls_session_set_verify_cert</code></a></td><td class="printindex-index-section"><a href="#Certificate-credentials">Certificate credentials</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsession_005fset_005fverify_005fcert-1"><code>gnutls_session_set_verify_cert</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsession_005fset_005fverify_005fcert2"><code>gnutls_session_set_verify_cert2</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsession_005fset_005fverify_005ffunction"><code>gnutls_session_set_verify_function</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsession_005fset_005fverify_005foutput_005ffunction"><code>gnutls_session_set_verify_output_function</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsession_005fsupplemental_005fregister"><code>gnutls_session_supplemental_register</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsession_005fticket_005fenable_005fclient"><code>gnutls_session_ticket_enable_client</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsession_005fticket_005fenable_005fserver"><code>gnutls_session_ticket_enable_server</code></a></td><td class="printindex-index-section"><a href="#Session-resumption">Session resumption</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsession_005fticket_005fenable_005fserver-1"><code>gnutls_session_ticket_enable_server</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsession_005fticket_005fkey_005fgenerate"><code>gnutls_session_ticket_key_generate</code></a></td><td class="printindex-index-section"><a href="#Session-resumption">Session resumption</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsession_005fticket_005fkey_005fgenerate-1"><code>gnutls_session_ticket_key_generate</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsession_005fticket_005fsend"><code>gnutls_session_ticket_send</code></a></td><td class="printindex-index-section"><a href="#Session-resumption">Session resumption</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsession_005fticket_005fsend-1"><code>gnutls_session_ticket_send</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fset_005fdefault_005fpriority"><code>gnutls_set_default_priority</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fset_005fdefault_005fpriority_005fappend"><code>gnutls_set_default_priority_append</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsign_005falgorithm_005fget"><code>gnutls_sign_algorithm_get</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsign_005falgorithm_005fget_005fclient"><code>gnutls_sign_algorithm_get_client</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsign_005falgorithm_005fget_005frequested"><code>gnutls_sign_algorithm_get_requested</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsign_005fget_005fhash_005falgorithm"><code>gnutls_sign_get_hash_algorithm</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsign_005fget_005fid"><code>gnutls_sign_get_id</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsign_005fget_005fname"><code>gnutls_sign_get_name</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsign_005fget_005foid"><code>gnutls_sign_get_oid</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsign_005fget_005fpk_005falgorithm"><code>gnutls_sign_get_pk_algorithm</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsign_005fis_005fsecure"><code>gnutls_sign_is_secure</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsign_005fis_005fsecure2"><code>gnutls_sign_is_secure2</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsign_005flist"><code>gnutls_sign_list</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsign_005fset_005fsecure"><code>gnutls_sign_set_secure</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsign_005fset_005fsecure_005ffor_005fcerts"><code>gnutls_sign_set_secure_for_certs</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsign_005fsupports_005fpk_005falgorithm"><code>gnutls_sign_supports_pk_algorithm</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsrp_005fallocate_005fclient_005fcredentials"><code>gnutls_srp_allocate_client_credentials</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsrp_005fallocate_005fserver_005fcredentials"><code>gnutls_srp_allocate_server_credentials</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsrp_005fbase64_005fdecode"><code>gnutls_srp_base64_decode</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsrp_005fbase64_005fdecode2"><code>gnutls_srp_base64_decode2</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsrp_005fbase64_005fencode"><code>gnutls_srp_base64_encode</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsrp_005fbase64_005fencode2"><code>gnutls_srp_base64_encode2</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsrp_005ffree_005fclient_005fcredentials"><code>gnutls_srp_free_client_credentials</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsrp_005ffree_005fserver_005fcredentials"><code>gnutls_srp_free_server_credentials</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsrp_005fserver_005fget_005fusername"><code>gnutls_srp_server_get_username</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsrp_005fset_005fclient_005fcredentials"><code>gnutls_srp_set_client_credentials</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsrp_005fset_005fclient_005fcredentials_005ffunction"><code>gnutls_srp_set_client_credentials_function</code></a></td><td class="printindex-index-section"><a href="#SRP-credentials">SRP credentials</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsrp_005fset_005fclient_005fcredentials_005ffunction-1"><code>gnutls_srp_set_client_credentials_function</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsrp_005fset_005fprime_005fbits"><code>gnutls_srp_set_prime_bits</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsrp_005fset_005fserver_005fcredentials_005ffile"><code>gnutls_srp_set_server_credentials_file</code></a></td><td class="printindex-index-section"><a href="#SRP-credentials">SRP credentials</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsrp_005fset_005fserver_005fcredentials_005ffile-1"><code>gnutls_srp_set_server_credentials_file</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsrp_005fset_005fserver_005fcredentials_005ffunction"><code>gnutls_srp_set_server_credentials_function</code></a></td><td class="printindex-index-section"><a href="#SRP-credentials">SRP credentials</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsrp_005fset_005fserver_005fcredentials_005ffunction-1"><code>gnutls_srp_set_server_credentials_function</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsrp_005fset_005fserver_005ffake_005fsalt_005fseed"><code>gnutls_srp_set_server_fake_salt_seed</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsrp_005fverifier"><code>gnutls_srp_verifier</code></a></td><td class="printindex-index-section"><a href="#Authentication-using-SRP">Authentication using SRP</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsrp_005fverifier-1"><code>gnutls_srp_verifier</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsrtp_005fget_005fkeys"><code>gnutls_srtp_get_keys</code></a></td><td class="printindex-index-section"><a href="#SRTP">SRTP</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsrtp_005fget_005fkeys-1"><code>gnutls_srtp_get_keys</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsrtp_005fget_005fmki"><code>gnutls_srtp_get_mki</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsrtp_005fget_005fprofile_005fid"><code>gnutls_srtp_get_profile_id</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsrtp_005fget_005fprofile_005fname"><code>gnutls_srtp_get_profile_name</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsrtp_005fget_005fselected_005fprofile"><code>gnutls_srtp_get_selected_profile</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsrtp_005fset_005fmki"><code>gnutls_srtp_set_mki</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsrtp_005fset_005fprofile"><code>gnutls_srtp_set_profile</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsrtp_005fset_005fprofile_005fdirect"><code>gnutls_srtp_set_profile_direct</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fstore_005fcommitment"><code>gnutls_store_commitment</code></a></td><td class="printindex-index-section"><a href="#Certificate-verification">Certificate verification</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fstore_005fcommitment-1"><code>gnutls_store_commitment</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fstore_005fpubkey"><code>gnutls_store_pubkey</code></a></td><td class="printindex-index-section"><a href="#Certificate-verification">Certificate verification</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fstore_005fpubkey-1"><code>gnutls_store_pubkey</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fstrerror"><code>gnutls_strerror</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fstrerror_005fname"><code>gnutls_strerror_name</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsubject_005falt_005fnames_005fdeinit"><code>gnutls_subject_alt_names_deinit</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsubject_005falt_005fnames_005fget"><code>gnutls_subject_alt_names_get</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsubject_005falt_005fnames_005finit"><code>gnutls_subject_alt_names_init</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsubject_005falt_005fnames_005fset"><code>gnutls_subject_alt_names_set</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsupplemental_005fget_005fname"><code>gnutls_supplemental_get_name</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsupplemental_005frecv"><code>gnutls_supplemental_recv</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsupplemental_005fregister"><code>gnutls_supplemental_register</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsupplemental_005fsend"><code>gnutls_supplemental_send</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsystem_005fkey_005fadd_005fx509"><code>gnutls_system_key_add_x509</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsystem_005fkey_005fdelete"><code>gnutls_system_key_delete</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsystem_005fkey_005fiter_005fdeinit"><code>gnutls_system_key_iter_deinit</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsystem_005fkey_005fiter_005fget_005finfo"><code>gnutls_system_key_iter_get_info</code></a></td><td class="printindex-index-section"><a href="#Application_002dspecific-keys">Application-specific keys</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsystem_005fkey_005fiter_005fget_005finfo-1"><code>gnutls_system_key_iter_get_info</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fsystem_005frecv_005ftimeout"><code>gnutls_system_recv_timeout</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ftdb_005fdeinit"><code>gnutls_tdb_deinit</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ftdb_005finit"><code>gnutls_tdb_init</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ftdb_005fset_005fstore_005fcommitment_005ffunc"><code>gnutls_tdb_set_store_commitment_func</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ftdb_005fset_005fstore_005ffunc"><code>gnutls_tdb_set_store_func</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ftdb_005fset_005fverify_005ffunc"><code>gnutls_tdb_set_verify_func</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ftpm_005fget_005fregistered"><code>gnutls_tpm_get_registered</code></a></td><td class="printindex-index-section"><a href="#TPM-API">TPM API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ftpm_005fkey_005flist_005fdeinit"><code>gnutls_tpm_key_list_deinit</code></a></td><td class="printindex-index-section"><a href="#TPM-API">TPM API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ftpm_005fkey_005flist_005fget_005furl"><code>gnutls_tpm_key_list_get_url</code></a></td><td class="printindex-index-section"><a href="#TPM-API">TPM API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ftpm_005fprivkey_005fdelete"><code>gnutls_tpm_privkey_delete</code></a></td><td class="printindex-index-section"><a href="#Key-generation">Key generation</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ftpm_005fprivkey_005fdelete-1"><code>gnutls_tpm_privkey_delete</code></a></td><td class="printindex-index-section"><a href="#Using-keys">Using keys</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ftpm_005fprivkey_005fdelete-2"><code>gnutls_tpm_privkey_delete</code></a></td><td class="printindex-index-section"><a href="#TPM-API">TPM API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ftpm_005fprivkey_005fgenerate"><code>gnutls_tpm_privkey_generate</code></a></td><td class="printindex-index-section"><a href="#Key-generation">Key generation</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ftpm_005fprivkey_005fgenerate-1"><code>gnutls_tpm_privkey_generate</code></a></td><td class="printindex-index-section"><a href="#TPM-API">TPM API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ftransport_005fget_005fint"><code>gnutls_transport_get_int</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ftransport_005fget_005fint2"><code>gnutls_transport_get_int2</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ftransport_005fget_005fptr"><code>gnutls_transport_get_ptr</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ftransport_005fget_005fptr2"><code>gnutls_transport_get_ptr2</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ftransport_005fis_005fktls_005fenabled"><code>gnutls_transport_is_ktls_enabled</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ftransport_005fset_005ferrno"><code>gnutls_transport_set_errno</code></a></td><td class="printindex-index-section"><a href="#Setting-up-the-transport-layer">Setting up the transport layer</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ftransport_005fset_005ferrno-1"><code>gnutls_transport_set_errno</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ftransport_005fset_005ferrno_005ffunction"><code>gnutls_transport_set_errno_function</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ftransport_005fset_005ffastopen"><code>gnutls_transport_set_fastopen</code></a></td><td class="printindex-index-section"><a href="#Reducing-round_002dtrips">Reducing round-trips</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ftransport_005fset_005ffastopen-1"><code>gnutls_transport_set_fastopen</code></a></td><td class="printindex-index-section"><a href="#Socket-specific-API">Socket specific API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ftransport_005fset_005fint"><code>gnutls_transport_set_int</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ftransport_005fset_005fint2"><code>gnutls_transport_set_int2</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ftransport_005fset_005fptr"><code>gnutls_transport_set_ptr</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ftransport_005fset_005fptr2"><code>gnutls_transport_set_ptr2</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ftransport_005fset_005fpull_005ffunction"><code>gnutls_transport_set_pull_function</code></a></td><td class="printindex-index-section"><a href="#Setting-up-the-transport-layer">Setting up the transport layer</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ftransport_005fset_005fpull_005ffunction-1"><code>gnutls_transport_set_pull_function</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ftransport_005fset_005fpull_005ftimeout_005ffunction"><code>gnutls_transport_set_pull_timeout_function</code></a></td><td class="printindex-index-section"><a href="#Setting-up-the-transport-layer">Setting up the transport layer</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ftransport_005fset_005fpull_005ftimeout_005ffunction-1"><code>gnutls_transport_set_pull_timeout_function</code></a></td><td class="printindex-index-section"><a href="#Setting-up-the-transport-layer">Setting up the transport layer</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ftransport_005fset_005fpull_005ftimeout_005ffunction-2"><code>gnutls_transport_set_pull_timeout_function</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ftransport_005fset_005fpush_005ffunction"><code>gnutls_transport_set_push_function</code></a></td><td class="printindex-index-section"><a href="#Setting-up-the-transport-layer">Setting up the transport layer</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ftransport_005fset_005fpush_005ffunction-1"><code>gnutls_transport_set_push_function</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ftransport_005fset_005fvec_005fpush_005ffunction"><code>gnutls_transport_set_vec_push_function</code></a></td><td class="printindex-index-section"><a href="#Setting-up-the-transport-layer">Setting up the transport layer</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005ftransport_005fset_005fvec_005fpush_005ffunction-1"><code>gnutls_transport_set_vec_push_function</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005furl_005fis_005fsupported"><code>gnutls_url_is_supported</code></a></td><td class="printindex-index-section"><a href="#Abstract-public-keys">Abstract public keys</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005furl_005fis_005fsupported-1"><code>gnutls_url_is_supported</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005futf8_005fpassword_005fnormalize"><code>gnutls_utf8_password_normalize</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fverify_005fstored_005fpubkey"><code>gnutls_verify_stored_pubkey</code></a></td><td class="printindex-index-section"><a href="#Certificate-verification">Certificate verification</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fverify_005fstored_005fpubkey-1"><code>gnutls_verify_stored_pubkey</code></a></td><td class="printindex-index-section"><a href="#Core-TLS-API">Core TLS API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005faia_005fdeinit"><code>gnutls_x509_aia_deinit</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005faia_005fget"><code>gnutls_x509_aia_get</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005faia_005finit"><code>gnutls_x509_aia_init</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005faia_005fset"><code>gnutls_x509_aia_set</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005faki_005fdeinit"><code>gnutls_x509_aki_deinit</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005faki_005fget_005fcert_005fissuer"><code>gnutls_x509_aki_get_cert_issuer</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005faki_005fget_005fid"><code>gnutls_x509_aki_get_id</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005faki_005finit"><code>gnutls_x509_aki_init</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005faki_005fset_005fcert_005fissuer"><code>gnutls_x509_aki_set_cert_issuer</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005faki_005fset_005fid"><code>gnutls_x509_aki_set_id</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcidr_005fto_005frfc5280"><code>gnutls_x509_cidr_to_rfc5280</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fcheck_005fissuer"><code>gnutls_x509_crl_check_issuer</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fdeinit"><code>gnutls_x509_crl_deinit</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fdist_005fpoints_005fdeinit"><code>gnutls_x509_crl_dist_points_deinit</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fdist_005fpoints_005fget"><code>gnutls_x509_crl_dist_points_get</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fdist_005fpoints_005finit"><code>gnutls_x509_crl_dist_points_init</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fdist_005fpoints_005fset"><code>gnutls_x509_crl_dist_points_set</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fexport"><code>gnutls_x509_crl_export</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fexport2"><code>gnutls_x509_crl_export2</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fget_005fauthority_005fkey_005fgn_005fserial"><code>gnutls_x509_crl_get_authority_key_gn_serial</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fget_005fauthority_005fkey_005fid"><code>gnutls_x509_crl_get_authority_key_id</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fget_005fcrt_005fcount"><code>gnutls_x509_crl_get_crt_count</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fget_005fcrt_005fserial"><code>gnutls_x509_crl_get_crt_serial</code></a></td><td class="printindex-index-section"><a href="#PKIX-certificate-revocation-lists">PKIX certificate revocation lists</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fget_005fcrt_005fserial-1"><code>gnutls_x509_crl_get_crt_serial</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fget_005fdn_005foid"><code>gnutls_x509_crl_get_dn_oid</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fget_005fextension_005fdata"><code>gnutls_x509_crl_get_extension_data</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fget_005fextension_005fdata2"><code>gnutls_x509_crl_get_extension_data2</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fget_005fextension_005finfo"><code>gnutls_x509_crl_get_extension_info</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fget_005fextension_005foid"><code>gnutls_x509_crl_get_extension_oid</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fget_005fissuer_005fdn"><code>gnutls_x509_crl_get_issuer_dn</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fget_005fissuer_005fdn_005fby_005foid"><code>gnutls_x509_crl_get_issuer_dn_by_oid</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fget_005fissuer_005fdn2"><code>gnutls_x509_crl_get_issuer_dn2</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fget_005fissuer_005fdn3"><code>gnutls_x509_crl_get_issuer_dn3</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fget_005fnext_005fupdate"><code>gnutls_x509_crl_get_next_update</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fget_005fnumber"><code>gnutls_x509_crl_get_number</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fget_005fraw_005fissuer_005fdn"><code>gnutls_x509_crl_get_raw_issuer_dn</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fget_005fsignature"><code>gnutls_x509_crl_get_signature</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fget_005fsignature_005falgorithm"><code>gnutls_x509_crl_get_signature_algorithm</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fget_005fsignature_005foid"><code>gnutls_x509_crl_get_signature_oid</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fget_005fthis_005fupdate"><code>gnutls_x509_crl_get_this_update</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fget_005fversion"><code>gnutls_x509_crl_get_version</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fimport"><code>gnutls_x509_crl_import</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005finit"><code>gnutls_x509_crl_init</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fiter_005fcrt_005fserial"><code>gnutls_x509_crl_iter_crt_serial</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fiter_005fdeinit"><code>gnutls_x509_crl_iter_deinit</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005flist_005fimport"><code>gnutls_x509_crl_list_import</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005flist_005fimport2"><code>gnutls_x509_crl_list_import2</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fprint"><code>gnutls_x509_crl_print</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fprivkey_005fsign"><code>gnutls_x509_crl_privkey_sign</code></a></td><td class="printindex-index-section"><a href="#PKIX-certificate-revocation-lists">PKIX certificate revocation lists</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fprivkey_005fsign-1"><code>gnutls_x509_crl_privkey_sign</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fset_005fauthority_005fkey_005fid"><code>gnutls_x509_crl_set_authority_key_id</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fset_005fcrt"><code>gnutls_x509_crl_set_crt</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fset_005fcrt_005fserial"><code>gnutls_x509_crl_set_crt_serial</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fset_005fnext_005fupdate"><code>gnutls_x509_crl_set_next_update</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fset_005fnumber"><code>gnutls_x509_crl_set_number</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fset_005fthis_005fupdate"><code>gnutls_x509_crl_set_this_update</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fset_005fversion"><code>gnutls_x509_crl_set_version</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fsign"><code>gnutls_x509_crl_sign</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fsign2"><code>gnutls_x509_crl_sign2</code></a></td><td class="printindex-index-section"><a href="#PKIX-certificate-revocation-lists">PKIX certificate revocation lists</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fsign2-1"><code>gnutls_x509_crl_sign2</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrl_005fverify"><code>gnutls_x509_crl_verify</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fdeinit"><code>gnutls_x509_crq_deinit</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fexport"><code>gnutls_x509_crq_export</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fexport2"><code>gnutls_x509_crq_export2</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fget_005fattribute_005fby_005foid"><code>gnutls_x509_crq_get_attribute_by_oid</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fget_005fattribute_005fdata"><code>gnutls_x509_crq_get_attribute_data</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fget_005fattribute_005finfo"><code>gnutls_x509_crq_get_attribute_info</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fget_005fbasic_005fconstraints"><code>gnutls_x509_crq_get_basic_constraints</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fget_005fchallenge_005fpassword"><code>gnutls_x509_crq_get_challenge_password</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fget_005fdn"><code>gnutls_x509_crq_get_dn</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fget_005fdn_005fby_005foid"><code>gnutls_x509_crq_get_dn_by_oid</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fget_005fdn_005foid"><code>gnutls_x509_crq_get_dn_oid</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fget_005fdn2"><code>gnutls_x509_crq_get_dn2</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fget_005fdn3"><code>gnutls_x509_crq_get_dn3</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fget_005fextension_005fby_005foid"><code>gnutls_x509_crq_get_extension_by_oid</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fget_005fextension_005fby_005foid2"><code>gnutls_x509_crq_get_extension_by_oid2</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fget_005fextension_005fdata"><code>gnutls_x509_crq_get_extension_data</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fget_005fextension_005fdata2"><code>gnutls_x509_crq_get_extension_data2</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fget_005fextension_005finfo"><code>gnutls_x509_crq_get_extension_info</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fget_005fkey_005fid"><code>gnutls_x509_crq_get_key_id</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fget_005fkey_005fpurpose_005foid"><code>gnutls_x509_crq_get_key_purpose_oid</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fget_005fkey_005frsa_005fraw"><code>gnutls_x509_crq_get_key_rsa_raw</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fget_005fkey_005fusage"><code>gnutls_x509_crq_get_key_usage</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fget_005fpk_005falgorithm"><code>gnutls_x509_crq_get_pk_algorithm</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fget_005fpk_005foid"><code>gnutls_x509_crq_get_pk_oid</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fget_005fprivate_005fkey_005fusage_005fperiod"><code>gnutls_x509_crq_get_private_key_usage_period</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fget_005fsignature_005falgorithm"><code>gnutls_x509_crq_get_signature_algorithm</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fget_005fsignature_005foid"><code>gnutls_x509_crq_get_signature_oid</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fget_005fspki"><code>gnutls_x509_crq_get_spki</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fget_005fsubject_005falt_005fname"><code>gnutls_x509_crq_get_subject_alt_name</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fget_005fsubject_005falt_005fothername_005foid"><code>gnutls_x509_crq_get_subject_alt_othername_oid</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fget_005ftlsfeatures"><code>gnutls_x509_crq_get_tlsfeatures</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fget_005fversion"><code>gnutls_x509_crq_get_version</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fimport"><code>gnutls_x509_crq_import</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005finit"><code>gnutls_x509_crq_init</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fprint"><code>gnutls_x509_crq_print</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fprivkey_005fsign"><code>gnutls_x509_crq_privkey_sign</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fset_005fattribute_005fby_005foid"><code>gnutls_x509_crq_set_attribute_by_oid</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fset_005fbasic_005fconstraints"><code>gnutls_x509_crq_set_basic_constraints</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fset_005fchallenge_005fpassword"><code>gnutls_x509_crq_set_challenge_password</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fset_005fdn"><code>gnutls_x509_crq_set_dn</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fset_005fdn_005fby_005foid"><code>gnutls_x509_crq_set_dn_by_oid</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fset_005fextension_005fby_005foid"><code>gnutls_x509_crq_set_extension_by_oid</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fset_005fkey"><code>gnutls_x509_crq_set_key</code></a></td><td class="printindex-index-section"><a href="#PKCS-10-certificate-requests">PKCS 10 certificate requests</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fset_005fkey-1"><code>gnutls_x509_crq_set_key</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fset_005fkey_005fpurpose_005foid"><code>gnutls_x509_crq_set_key_purpose_oid</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fset_005fkey_005frsa_005fraw"><code>gnutls_x509_crq_set_key_rsa_raw</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fset_005fkey_005fusage"><code>gnutls_x509_crq_set_key_usage</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fset_005fprivate_005fkey_005fusage_005fperiod"><code>gnutls_x509_crq_set_private_key_usage_period</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fset_005fpubkey"><code>gnutls_x509_crq_set_pubkey</code></a></td><td class="printindex-index-section"><a href="#Operations">Operations</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fset_005fpubkey-1"><code>gnutls_x509_crq_set_pubkey</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fset_005fspki"><code>gnutls_x509_crq_set_spki</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fset_005fsubject_005falt_005fname"><code>gnutls_x509_crq_set_subject_alt_name</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fset_005fsubject_005falt_005fothername"><code>gnutls_x509_crq_set_subject_alt_othername</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fset_005ftlsfeatures"><code>gnutls_x509_crq_set_tlsfeatures</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fset_005fversion"><code>gnutls_x509_crq_set_version</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fsign"><code>gnutls_x509_crq_sign</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fsign2"><code>gnutls_x509_crq_sign2</code></a></td><td class="printindex-index-section"><a href="#PKCS-10-certificate-requests">PKCS 10 certificate requests</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fsign2-1"><code>gnutls_x509_crq_sign2</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrq_005fverify"><code>gnutls_x509_crq_verify</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fcheck_005femail"><code>gnutls_x509_crt_check_email</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fcheck_005fhostname"><code>gnutls_x509_crt_check_hostname</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fcheck_005fhostname2"><code>gnutls_x509_crt_check_hostname2</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fcheck_005fip"><code>gnutls_x509_crt_check_ip</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fcheck_005fissuer"><code>gnutls_x509_crt_check_issuer</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fcheck_005fkey_005fpurpose"><code>gnutls_x509_crt_check_key_purpose</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fcheck_005frevocation"><code>gnutls_x509_crt_check_revocation</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fcpy_005fcrl_005fdist_005fpoints"><code>gnutls_x509_crt_cpy_crl_dist_points</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fdeinit"><code>gnutls_x509_crt_deinit</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fequals"><code>gnutls_x509_crt_equals</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fequals2"><code>gnutls_x509_crt_equals2</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fexport"><code>gnutls_x509_crt_export</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fexport2"><code>gnutls_x509_crt_export2</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005factivation_005ftime"><code>gnutls_x509_crt_get_activation_time</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fauthority_005finfo_005faccess"><code>gnutls_x509_crt_get_authority_info_access</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fauthority_005fkey_005fgn_005fserial"><code>gnutls_x509_crt_get_authority_key_gn_serial</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fauthority_005fkey_005fid"><code>gnutls_x509_crt_get_authority_key_id</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fbasic_005fconstraints"><code>gnutls_x509_crt_get_basic_constraints</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fca_005fstatus"><code>gnutls_x509_crt_get_ca_status</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fcrl_005fdist_005fpoints"><code>gnutls_x509_crt_get_crl_dist_points</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fdn"><code>gnutls_x509_crt_get_dn</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fdn_005fby_005foid"><code>gnutls_x509_crt_get_dn_by_oid</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fdn_005foid"><code>gnutls_x509_crt_get_dn_oid</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fdn2"><code>gnutls_x509_crt_get_dn2</code></a></td><td class="printindex-index-section"><a href="#X_002e509-distinguished-names">X.509 distinguished names</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fdn2-1"><code>gnutls_x509_crt_get_dn2</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fdn3"><code>gnutls_x509_crt_get_dn3</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fexpiration_005ftime"><code>gnutls_x509_crt_get_expiration_time</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fextension_005fby_005foid"><code>gnutls_x509_crt_get_extension_by_oid</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fextension_005fby_005foid2"><code>gnutls_x509_crt_get_extension_by_oid2</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fextension_005fdata"><code>gnutls_x509_crt_get_extension_data</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fextension_005fdata2"><code>gnutls_x509_crt_get_extension_data2</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fextension_005finfo"><code>gnutls_x509_crt_get_extension_info</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fextension_005foid"><code>gnutls_x509_crt_get_extension_oid</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005ffingerprint"><code>gnutls_x509_crt_get_fingerprint</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005finhibit_005fanypolicy"><code>gnutls_x509_crt_get_inhibit_anypolicy</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fissuer"><code>gnutls_x509_crt_get_issuer</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fissuer_005falt_005fname"><code>gnutls_x509_crt_get_issuer_alt_name</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fissuer_005falt_005fname2"><code>gnutls_x509_crt_get_issuer_alt_name2</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fissuer_005falt_005fothername_005foid"><code>gnutls_x509_crt_get_issuer_alt_othername_oid</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn"><code>gnutls_x509_crt_get_issuer_dn</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn_005fby_005foid"><code>gnutls_x509_crt_get_issuer_dn_by_oid</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn_005foid"><code>gnutls_x509_crt_get_issuer_dn_oid</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn2"><code>gnutls_x509_crt_get_issuer_dn2</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn3"><code>gnutls_x509_crt_get_issuer_dn3</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fissuer_005funique_005fid"><code>gnutls_x509_crt_get_issuer_unique_id</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fkey_005fid"><code>gnutls_x509_crt_get_key_id</code></a></td><td class="printindex-index-section"><a href="#X_002e509-public-and-private-keys">X.509 public and private keys</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fkey_005fid-1"><code>gnutls_x509_crt_get_key_id</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fkey_005fpurpose_005foid"><code>gnutls_x509_crt_get_key_purpose_oid</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fkey_005fusage"><code>gnutls_x509_crt_get_key_usage</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fname_005fconstraints"><code>gnutls_x509_crt_get_name_constraints</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fpk_005falgorithm"><code>gnutls_x509_crt_get_pk_algorithm</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fpk_005fdsa_005fraw"><code>gnutls_x509_crt_get_pk_dsa_raw</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fpk_005fecc_005fraw"><code>gnutls_x509_crt_get_pk_ecc_raw</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fpk_005fgost_005fraw"><code>gnutls_x509_crt_get_pk_gost_raw</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fpk_005foid"><code>gnutls_x509_crt_get_pk_oid</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fpk_005frsa_005fraw"><code>gnutls_x509_crt_get_pk_rsa_raw</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fpolicy"><code>gnutls_x509_crt_get_policy</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fpreferred_005fhash_005falgorithm"><code>gnutls_x509_crt_get_preferred_hash_algorithm</code></a></td><td class="printindex-index-section"><a href="#Compatibility-API">Compatibility API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fprivate_005fkey_005fusage_005fperiod"><code>gnutls_x509_crt_get_private_key_usage_period</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fproxy"><code>gnutls_x509_crt_get_proxy</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fraw_005fdn"><code>gnutls_x509_crt_get_raw_dn</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fraw_005fissuer_005fdn"><code>gnutls_x509_crt_get_raw_issuer_dn</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fserial"><code>gnutls_x509_crt_get_serial</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fsignature"><code>gnutls_x509_crt_get_signature</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fsignature_005falgorithm"><code>gnutls_x509_crt_get_signature_algorithm</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fsignature_005foid"><code>gnutls_x509_crt_get_signature_oid</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fspki"><code>gnutls_x509_crt_get_spki</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fsubject"><code>gnutls_x509_crt_get_subject</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fsubject_005falt_005fname"><code>gnutls_x509_crt_get_subject_alt_name</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fsubject_005falt_005fname2"><code>gnutls_x509_crt_get_subject_alt_name2</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fsubject_005falt_005fothername_005foid"><code>gnutls_x509_crt_get_subject_alt_othername_oid</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fsubject_005fkey_005fid"><code>gnutls_x509_crt_get_subject_key_id</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fsubject_005funique_005fid"><code>gnutls_x509_crt_get_subject_unique_id</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005ftlsfeatures"><code>gnutls_x509_crt_get_tlsfeatures</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fget_005fversion"><code>gnutls_x509_crt_get_version</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fimport"><code>gnutls_x509_crt_import</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fimport_005fpkcs11"><code>gnutls_x509_crt_import_pkcs11</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fimport_005furl"><code>gnutls_x509_crt_import_url</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005finit"><code>gnutls_x509_crt_init</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005flist_005fimport"><code>gnutls_x509_crt_list_import</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005flist_005fimport_005fpkcs11"><code>gnutls_x509_crt_list_import_pkcs11</code></a></td><td class="printindex-index-section"><a href="#PKCS-11-API">PKCS 11 API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005flist_005fimport_005furl"><code>gnutls_x509_crt_list_import_url</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005flist_005fimport2"><code>gnutls_x509_crt_list_import2</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005flist_005fverify"><code>gnutls_x509_crt_list_verify</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fprint"><code>gnutls_x509_crt_print</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fprivkey_005fsign"><code>gnutls_x509_crt_privkey_sign</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fset_005factivation_005ftime"><code>gnutls_x509_crt_set_activation_time</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fset_005fauthority_005finfo_005faccess"><code>gnutls_x509_crt_set_authority_info_access</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fset_005fauthority_005fkey_005fid"><code>gnutls_x509_crt_set_authority_key_id</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fset_005fbasic_005fconstraints"><code>gnutls_x509_crt_set_basic_constraints</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fset_005fca_005fstatus"><code>gnutls_x509_crt_set_ca_status</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fset_005fcrl_005fdist_005fpoints"><code>gnutls_x509_crt_set_crl_dist_points</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fset_005fcrl_005fdist_005fpoints2"><code>gnutls_x509_crt_set_crl_dist_points2</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fset_005fcrq"><code>gnutls_x509_crt_set_crq</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fset_005fcrq_005fextension_005fby_005foid"><code>gnutls_x509_crt_set_crq_extension_by_oid</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fset_005fcrq_005fextensions"><code>gnutls_x509_crt_set_crq_extensions</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fset_005fdn"><code>gnutls_x509_crt_set_dn</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fset_005fdn_005fby_005foid"><code>gnutls_x509_crt_set_dn_by_oid</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fset_005fexpiration_005ftime"><code>gnutls_x509_crt_set_expiration_time</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fset_005fextension_005fby_005foid"><code>gnutls_x509_crt_set_extension_by_oid</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fset_005fflags"><code>gnutls_x509_crt_set_flags</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fset_005finhibit_005fanypolicy"><code>gnutls_x509_crt_set_inhibit_anypolicy</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fset_005fissuer_005falt_005fname"><code>gnutls_x509_crt_set_issuer_alt_name</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fset_005fissuer_005falt_005fothername"><code>gnutls_x509_crt_set_issuer_alt_othername</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fset_005fissuer_005fdn"><code>gnutls_x509_crt_set_issuer_dn</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fset_005fissuer_005fdn_005fby_005foid"><code>gnutls_x509_crt_set_issuer_dn_by_oid</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fset_005fissuer_005funique_005fid"><code>gnutls_x509_crt_set_issuer_unique_id</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fset_005fkey"><code>gnutls_x509_crt_set_key</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fset_005fkey_005fpurpose_005foid"><code>gnutls_x509_crt_set_key_purpose_oid</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fset_005fkey_005fusage"><code>gnutls_x509_crt_set_key_usage</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fset_005fname_005fconstraints"><code>gnutls_x509_crt_set_name_constraints</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fset_005fpin_005ffunction"><code>gnutls_x509_crt_set_pin_function</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fset_005fpolicy"><code>gnutls_x509_crt_set_policy</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fset_005fprivate_005fkey_005fusage_005fperiod"><code>gnutls_x509_crt_set_private_key_usage_period</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fset_005fproxy"><code>gnutls_x509_crt_set_proxy</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fset_005fproxy_005fdn"><code>gnutls_x509_crt_set_proxy_dn</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fset_005fpubkey"><code>gnutls_x509_crt_set_pubkey</code></a></td><td class="printindex-index-section"><a href="#Operations">Operations</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fset_005fpubkey-1"><code>gnutls_x509_crt_set_pubkey</code></a></td><td class="printindex-index-section"><a href="#Abstract-key-API">Abstract key API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fset_005fserial"><code>gnutls_x509_crt_set_serial</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fset_005fspki"><code>gnutls_x509_crt_set_spki</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fset_005fsubject_005falt_005fname"><code>gnutls_x509_crt_set_subject_alt_name</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fset_005fsubject_005falt_005fothername"><code>gnutls_x509_crt_set_subject_alt_othername</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fset_005fsubject_005falternative_005fname"><code>gnutls_x509_crt_set_subject_alternative_name</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fset_005fsubject_005fkey_005fid"><code>gnutls_x509_crt_set_subject_key_id</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fset_005fsubject_005funique_005fid"><code>gnutls_x509_crt_set_subject_unique_id</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fset_005ftlsfeatures"><code>gnutls_x509_crt_set_tlsfeatures</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fset_005fversion"><code>gnutls_x509_crt_set_version</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fsign"><code>gnutls_x509_crt_sign</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fsign2"><code>gnutls_x509_crt_sign2</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fverify"><code>gnutls_x509_crt_verify</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fcrt_005fverify_005fdata2"><code>gnutls_x509_crt_verify_data2</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fct_005fsct_005fget"><code>gnutls_x509_ct_sct_get</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fct_005fsct_005fget_005fversion"><code>gnutls_x509_ct_sct_get_version</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fdn_005fdeinit"><code>gnutls_x509_dn_deinit</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fdn_005fexport"><code>gnutls_x509_dn_export</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fdn_005fexport2"><code>gnutls_x509_dn_export2</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fdn_005fget_005frdn_005fava"><code>gnutls_x509_dn_get_rdn_ava</code></a></td><td class="printindex-index-section"><a href="#X_002e509-distinguished-names">X.509 distinguished names</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fdn_005fget_005frdn_005fava-1"><code>gnutls_x509_dn_get_rdn_ava</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fdn_005fget_005fstr"><code>gnutls_x509_dn_get_str</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fdn_005fget_005fstr2"><code>gnutls_x509_dn_get_str2</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fdn_005fimport"><code>gnutls_x509_dn_import</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fdn_005finit"><code>gnutls_x509_dn_init</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fdn_005foid_005fknown"><code>gnutls_x509_dn_oid_known</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fdn_005foid_005fname"><code>gnutls_x509_dn_oid_name</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fdn_005fset_005fstr"><code>gnutls_x509_dn_set_str</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fext_005fct_005fexport_005fscts"><code>gnutls_x509_ext_ct_export_scts</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fext_005fct_005fimport_005fscts"><code>gnutls_x509_ext_ct_import_scts</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fext_005fct_005fscts_005fdeinit"><code>gnutls_x509_ext_ct_scts_deinit</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fext_005fct_005fscts_005finit"><code>gnutls_x509_ext_ct_scts_init</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fext_005fdeinit"><code>gnutls_x509_ext_deinit</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fext_005fexport_005faia"><code>gnutls_x509_ext_export_aia</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fext_005fexport_005fauthority_005fkey_005fid"><code>gnutls_x509_ext_export_authority_key_id</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fext_005fexport_005fbasic_005fconstraints"><code>gnutls_x509_ext_export_basic_constraints</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fext_005fexport_005fcrl_005fdist_005fpoints"><code>gnutls_x509_ext_export_crl_dist_points</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fext_005fexport_005finhibit_005fanypolicy"><code>gnutls_x509_ext_export_inhibit_anypolicy</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fext_005fexport_005fkey_005fpurposes"><code>gnutls_x509_ext_export_key_purposes</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fext_005fexport_005fkey_005fusage"><code>gnutls_x509_ext_export_key_usage</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fext_005fexport_005fname_005fconstraints"><code>gnutls_x509_ext_export_name_constraints</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fext_005fexport_005fpolicies"><code>gnutls_x509_ext_export_policies</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fext_005fexport_005fprivate_005fkey_005fusage_005fperiod"><code>gnutls_x509_ext_export_private_key_usage_period</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fext_005fexport_005fproxy"><code>gnutls_x509_ext_export_proxy</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fext_005fexport_005fsubject_005falt_005fnames"><code>gnutls_x509_ext_export_subject_alt_names</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fext_005fexport_005fsubject_005fkey_005fid"><code>gnutls_x509_ext_export_subject_key_id</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fext_005fexport_005ftlsfeatures"><code>gnutls_x509_ext_export_tlsfeatures</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fext_005fimport_005faia"><code>gnutls_x509_ext_import_aia</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fext_005fimport_005fauthority_005fkey_005fid"><code>gnutls_x509_ext_import_authority_key_id</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fext_005fimport_005fbasic_005fconstraints"><code>gnutls_x509_ext_import_basic_constraints</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fext_005fimport_005fcrl_005fdist_005fpoints"><code>gnutls_x509_ext_import_crl_dist_points</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fext_005fimport_005finhibit_005fanypolicy"><code>gnutls_x509_ext_import_inhibit_anypolicy</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fext_005fimport_005fkey_005fpurposes"><code>gnutls_x509_ext_import_key_purposes</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fext_005fimport_005fkey_005fusage"><code>gnutls_x509_ext_import_key_usage</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fext_005fimport_005fname_005fconstraints"><code>gnutls_x509_ext_import_name_constraints</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fext_005fimport_005fpolicies"><code>gnutls_x509_ext_import_policies</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fext_005fimport_005fprivate_005fkey_005fusage_005fperiod"><code>gnutls_x509_ext_import_private_key_usage_period</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fext_005fimport_005fproxy"><code>gnutls_x509_ext_import_proxy</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fext_005fimport_005fsubject_005falt_005fnames"><code>gnutls_x509_ext_import_subject_alt_names</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fext_005fimport_005fsubject_005fkey_005fid"><code>gnutls_x509_ext_import_subject_key_id</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fext_005fimport_005ftlsfeatures"><code>gnutls_x509_ext_import_tlsfeatures</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fext_005fprint"><code>gnutls_x509_ext_print</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fkey_005fpurpose_005fdeinit"><code>gnutls_x509_key_purpose_deinit</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fkey_005fpurpose_005fget"><code>gnutls_x509_key_purpose_get</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fkey_005fpurpose_005finit"><code>gnutls_x509_key_purpose_init</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fkey_005fpurpose_005fset"><code>gnutls_x509_key_purpose_set</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fname_005fconstraints_005fadd_005fexcluded"><code>gnutls_x509_name_constraints_add_excluded</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fname_005fconstraints_005fadd_005fpermitted"><code>gnutls_x509_name_constraints_add_permitted</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fname_005fconstraints_005fcheck"><code>gnutls_x509_name_constraints_check</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fname_005fconstraints_005fcheck_005fcrt"><code>gnutls_x509_name_constraints_check_crt</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fname_005fconstraints_005fdeinit"><code>gnutls_x509_name_constraints_deinit</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fname_005fconstraints_005fget_005fexcluded"><code>gnutls_x509_name_constraints_get_excluded</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fname_005fconstraints_005fget_005fpermitted"><code>gnutls_x509_name_constraints_get_permitted</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fname_005fconstraints_005finit"><code>gnutls_x509_name_constraints_init</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fothername_005fto_005fvirtual"><code>gnutls_x509_othername_to_virtual</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fpolicies_005fdeinit"><code>gnutls_x509_policies_deinit</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fpolicies_005fget"><code>gnutls_x509_policies_get</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fpolicies_005finit"><code>gnutls_x509_policies_init</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fpolicies_005fset"><code>gnutls_x509_policies_set</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fpolicy_005frelease"><code>gnutls_x509_policy_release</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fprivkey_005fcpy"><code>gnutls_x509_privkey_cpy</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fprivkey_005fdeinit"><code>gnutls_x509_privkey_deinit</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fprivkey_005fexport"><code>gnutls_x509_privkey_export</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fprivkey_005fexport_005fdsa_005fraw"><code>gnutls_x509_privkey_export_dsa_raw</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fprivkey_005fexport_005fecc_005fraw"><code>gnutls_x509_privkey_export_ecc_raw</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fprivkey_005fexport_005fgost_005fraw"><code>gnutls_x509_privkey_export_gost_raw</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fprivkey_005fexport_005fpkcs8"><code>gnutls_x509_privkey_export_pkcs8</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fprivkey_005fexport_005frsa_005fraw"><code>gnutls_x509_privkey_export_rsa_raw</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fprivkey_005fexport_005frsa_005fraw2"><code>gnutls_x509_privkey_export_rsa_raw2</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fprivkey_005fexport2"><code>gnutls_x509_privkey_export2</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fprivkey_005fexport2_005fpkcs8"><code>gnutls_x509_privkey_export2_pkcs8</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fprivkey_005ffix"><code>gnutls_x509_privkey_fix</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fprivkey_005fgenerate"><code>gnutls_x509_privkey_generate</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fprivkey_005fgenerate2"><code>gnutls_x509_privkey_generate2</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fprivkey_005fget_005fkey_005fid"><code>gnutls_x509_privkey_get_key_id</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fprivkey_005fget_005fpk_005falgorithm"><code>gnutls_x509_privkey_get_pk_algorithm</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fprivkey_005fget_005fpk_005falgorithm2"><code>gnutls_x509_privkey_get_pk_algorithm2</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fprivkey_005fget_005fseed"><code>gnutls_x509_privkey_get_seed</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fprivkey_005fget_005fspki"><code>gnutls_x509_privkey_get_spki</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fprivkey_005fimport"><code>gnutls_x509_privkey_import</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fprivkey_005fimport_005fdh_005fraw"><code>gnutls_x509_privkey_import_dh_raw</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fprivkey_005fimport_005fdsa_005fraw"><code>gnutls_x509_privkey_import_dsa_raw</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fprivkey_005fimport_005fecc_005fraw"><code>gnutls_x509_privkey_import_ecc_raw</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fprivkey_005fimport_005fgost_005fraw"><code>gnutls_x509_privkey_import_gost_raw</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fprivkey_005fimport_005fopenssl"><code>gnutls_x509_privkey_import_openssl</code></a></td><td class="printindex-index-section"><a href="#Managing-encrypted-keys">Managing encrypted keys</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fprivkey_005fimport_005fopenssl-1"><code>gnutls_x509_privkey_import_openssl</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fprivkey_005fimport_005fpkcs8"><code>gnutls_x509_privkey_import_pkcs8</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fprivkey_005fimport_005frsa_005fraw"><code>gnutls_x509_privkey_import_rsa_raw</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fprivkey_005fimport_005frsa_005fraw2"><code>gnutls_x509_privkey_import_rsa_raw2</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fprivkey_005fimport2"><code>gnutls_x509_privkey_import2</code></a></td><td class="printindex-index-section"><a href="#Managing-encrypted-keys">Managing encrypted keys</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fprivkey_005fimport2-1"><code>gnutls_x509_privkey_import2</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fprivkey_005finit"><code>gnutls_x509_privkey_init</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fprivkey_005fsec_005fparam"><code>gnutls_x509_privkey_sec_param</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fprivkey_005fset_005fflags"><code>gnutls_x509_privkey_set_flags</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fprivkey_005fset_005fpin_005ffunction"><code>gnutls_x509_privkey_set_pin_function</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fprivkey_005fset_005fspki"><code>gnutls_x509_privkey_set_spki</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fprivkey_005fsign_005fdata"><code>gnutls_x509_privkey_sign_data</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fprivkey_005fsign_005fhash"><code>gnutls_x509_privkey_sign_hash</code></a></td><td class="printindex-index-section"><a href="#Compatibility-API">Compatibility API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fprivkey_005fverify_005fparams"><code>gnutls_x509_privkey_verify_params</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fprivkey_005fverify_005fseed"><code>gnutls_x509_privkey_verify_seed</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005frdn_005fget"><code>gnutls_x509_rdn_get</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005frdn_005fget_005fby_005foid"><code>gnutls_x509_rdn_get_by_oid</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005frdn_005fget_005foid"><code>gnutls_x509_rdn_get_oid</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005frdn_005fget2"><code>gnutls_x509_rdn_get2</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fspki_005fdeinit"><code>gnutls_x509_spki_deinit</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fspki_005fget_005frsa_005foaep_005fparams"><code>gnutls_x509_spki_get_rsa_oaep_params</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fspki_005fget_005frsa_005fpss_005fparams"><code>gnutls_x509_spki_get_rsa_pss_params</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fspki_005finit"><code>gnutls_x509_spki_init</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fspki_005fset_005frsa_005foaep_005fparams"><code>gnutls_x509_spki_set_rsa_oaep_params</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005fspki_005fset_005frsa_005fpss_005fparams"><code>gnutls_x509_spki_set_rsa_pss_params</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005ftlsfeatures_005fadd"><code>gnutls_x509_tlsfeatures_add</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005ftlsfeatures_005fcheck_005fcrt"><code>gnutls_x509_tlsfeatures_check_crt</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005ftlsfeatures_005fdeinit"><code>gnutls_x509_tlsfeatures_deinit</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005ftlsfeatures_005fget"><code>gnutls_x509_tlsfeatures_get</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005ftlsfeatures_005finit"><code>gnutls_x509_tlsfeatures_init</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005ftrust_005flist_005fadd_005fcas"><code>gnutls_x509_trust_list_add_cas</code></a></td><td class="printindex-index-section"><a href="#Verifying-X_002e509-certificate-paths">Verifying X.509 certificate paths</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005ftrust_005flist_005fadd_005fcas-1"><code>gnutls_x509_trust_list_add_cas</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005ftrust_005flist_005fadd_005fcrls"><code>gnutls_x509_trust_list_add_crls</code></a></td><td class="printindex-index-section"><a href="#Verifying-X_002e509-certificate-paths">Verifying X.509 certificate paths</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005ftrust_005flist_005fadd_005fcrls-1"><code>gnutls_x509_trust_list_add_crls</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005ftrust_005flist_005fadd_005fnamed_005fcrt"><code>gnutls_x509_trust_list_add_named_crt</code></a></td><td class="printindex-index-section"><a href="#Verifying-X_002e509-certificate-paths">Verifying X.509 certificate paths</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005ftrust_005flist_005fadd_005fnamed_005fcrt-1"><code>gnutls_x509_trust_list_add_named_crt</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005ftrust_005flist_005fadd_005fsystem_005ftrust"><code>gnutls_x509_trust_list_add_system_trust</code></a></td><td class="printindex-index-section"><a href="#Verifying-X_002e509-certificate-paths">Verifying X.509 certificate paths</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005ftrust_005flist_005fadd_005fsystem_005ftrust-1"><code>gnutls_x509_trust_list_add_system_trust</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005ftrust_005flist_005fadd_005ftrust_005fdir"><code>gnutls_x509_trust_list_add_trust_dir</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005ftrust_005flist_005fadd_005ftrust_005ffile"><code>gnutls_x509_trust_list_add_trust_file</code></a></td><td class="printindex-index-section"><a href="#Verifying-X_002e509-certificate-paths">Verifying X.509 certificate paths</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005ftrust_005flist_005fadd_005ftrust_005ffile-1"><code>gnutls_x509_trust_list_add_trust_file</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005ftrust_005flist_005fadd_005ftrust_005fmem"><code>gnutls_x509_trust_list_add_trust_mem</code></a></td><td class="printindex-index-section"><a href="#Verifying-X_002e509-certificate-paths">Verifying X.509 certificate paths</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005ftrust_005flist_005fadd_005ftrust_005fmem-1"><code>gnutls_x509_trust_list_add_trust_mem</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005ftrust_005flist_005fdeinit"><code>gnutls_x509_trust_list_deinit</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005ftrust_005flist_005fget_005fissuer"><code>gnutls_x509_trust_list_get_issuer</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005ftrust_005flist_005fget_005fissuer_005fby_005fdn"><code>gnutls_x509_trust_list_get_issuer_by_dn</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005ftrust_005flist_005fget_005fissuer_005fby_005fsubject_005fkey_005fid"><code>gnutls_x509_trust_list_get_issuer_by_subject_key_id</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005ftrust_005flist_005fget_005fptr"><code>gnutls_x509_trust_list_get_ptr</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005ftrust_005flist_005finit"><code>gnutls_x509_trust_list_init</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005ftrust_005flist_005fiter_005fdeinit"><code>gnutls_x509_trust_list_iter_deinit</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005ftrust_005flist_005fiter_005fget_005fca"><code>gnutls_x509_trust_list_iter_get_ca</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005ftrust_005flist_005fremove_005fcas"><code>gnutls_x509_trust_list_remove_cas</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005ftrust_005flist_005fremove_005ftrust_005ffile"><code>gnutls_x509_trust_list_remove_trust_file</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005ftrust_005flist_005fremove_005ftrust_005fmem"><code>gnutls_x509_trust_list_remove_trust_mem</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005ftrust_005flist_005fset_005fgetissuer_005ffunction"><code>gnutls_x509_trust_list_set_getissuer_function</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005ftrust_005flist_005fset_005fptr"><code>gnutls_x509_trust_list_set_ptr</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005ftrust_005flist_005fverify_005fcrt"><code>gnutls_x509_trust_list_verify_crt</code></a></td><td class="printindex-index-section"><a href="#Verifying-X_002e509-certificate-paths">Verifying X.509 certificate paths</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005ftrust_005flist_005fverify_005fcrt-1"><code>gnutls_x509_trust_list_verify_crt</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005ftrust_005flist_005fverify_005fcrt2"><code>gnutls_x509_trust_list_verify_crt2</code></a></td><td class="printindex-index-section"><a href="#Verifying-X_002e509-certificate-paths">Verifying X.509 certificate paths</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005ftrust_005flist_005fverify_005fcrt2-1"><code>gnutls_x509_trust_list_verify_crt2</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005ftrust_005flist_005fverify_005fnamed_005fcrt"><code>gnutls_x509_trust_list_verify_named_crt</code></a></td><td class="printindex-index-section"><a href="#Verifying-X_002e509-certificate-paths">Verifying X.509 certificate paths</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fx509_005ftrust_005flist_005fverify_005fnamed_005fcrt-1"><code>gnutls_x509_trust_list_verify_named_crt</code></a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td colspan="3"><hr></td></tr>
</table>
<table class="fn-letters-footer-printindex"><tr><th>Jump to: &nbsp; </th><td><a class="summary-letter-printindex" href="#Function-and-Data-Index_fn_letter-D"><b>D</b></a>
 &nbsp; 
<a class="summary-letter-printindex" href="#Function-and-Data-Index_fn_letter-G"><b>G</b></a>
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</td></tr></table>
</div>

<hr>
</div>
<div class="unnumbered-level-extent" id="Concept-Index">
<div class="nav-panel">
<p>
Previous: <a href="#Function-and-Data-Index" accesskey="p" rel="prev">Function and Data Index</a>, Up: <a href="#Top" accesskey="u" rel="up">GnuTLS</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<h2 class="unnumbered" id="Concept-Index-1"><span>Concept Index<a class="copiable-link" href="#Concept-Index-1"> &para;</a></span></h2>

<div class="printindex cp-printindex">
<table class="cp-letters-header-printindex"><tr><th>Jump to: &nbsp; </th><td><a class="summary-letter-printindex" href="#Concept-Index_cp_letter-A"><b>A</b></a>
 &nbsp; 
<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-B"><b>B</b></a>
 &nbsp; 
<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-C"><b>C</b></a>
 &nbsp; 
<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-D"><b>D</b></a>
 &nbsp; 
<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-E"><b>E</b></a>
 &nbsp; 
<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-F"><b>F</b></a>
 &nbsp; 
<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-G"><b>G</b></a>
 &nbsp; 
<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-H"><b>H</b></a>
 &nbsp; 
<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-I"><b>I</b></a>
 &nbsp; 
<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-K"><b>K</b></a>
 &nbsp; 
<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-M"><b>M</b></a>
 &nbsp; 
<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-O"><b>O</b></a>
 &nbsp; 
<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-P"><b>P</b></a>
 &nbsp; 
<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-R"><b>R</b></a>
 &nbsp; 
<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-S"><b>S</b></a>
 &nbsp; 
<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-T"><b>T</b></a>
 &nbsp; 
<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-U"><b>U</b></a>
 &nbsp; 
<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-V"><b>V</b></a>
 &nbsp; 
<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-X"><b>X</b></a>
 &nbsp; 
</td></tr></table>
<table class="cp-entries-printindex">
<tr><td></td><th class="entries-header-printindex">Index Entry</th><th class="sections-header-printindex">Section</th></tr>
<tr><td colspan="3"><hr></td></tr>
<tr><th id="Concept-Index_cp_letter-A">A</th></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-abstract-types">abstract types</a></td><td class="printindex-index-section"><a href="#Abstract-key-types">Abstract key types</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-alert-protocol">alert protocol</a></td><td class="printindex-index-section"><a href="#The-TLS-Alert-Protocol">The TLS Alert Protocol</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-ALPN">ALPN</a></td><td class="printindex-index-section"><a href="#Application-Layer-Protocol-Negotiation-_0028ALPN_0029">Application Layer Protocol Negotiation (ALPN)</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-anonymous-authentication">anonymous authentication</a></td><td class="printindex-index-section"><a href="#Anonymous-authentication">Anonymous authentication</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-API-reference">API reference</a></td><td class="printindex-index-section"><a href="#API-reference">API reference</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-Application-Layer-Protocol-Negotiation">Application Layer Protocol Negotiation</a></td><td class="printindex-index-section"><a href="#Application-Layer-Protocol-Negotiation-_0028ALPN_0029">Application Layer Protocol Negotiation (ALPN)</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-Application_002dspecific-keys">Application-specific keys</a></td><td class="printindex-index-section"><a href="#Application_002dspecific-keys">Application-specific keys</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-authentication-methods">authentication methods</a></td><td class="printindex-index-section"><a href="#Authentication-methods">Authentication methods</a></td></tr>
<tr><td colspan="3"><hr></td></tr>
<tr><th id="Concept-Index_cp_letter-B">B</th></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-bad_005frecord_005fmac">bad_record_mac</a></td><td class="printindex-index-section"><a href="#On-Record-Padding">On Record Padding</a></td></tr>
<tr><td colspan="3"><hr></td></tr>
<tr><th id="Concept-Index_cp_letter-C">C</th></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-callback-functions">callback functions</a></td><td class="printindex-index-section"><a href="#Callback-functions">Callback functions</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-certificate-authentication">certificate authentication</a></td><td class="printindex-index-section"><a href="#Certificate-authentication">Certificate authentication</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-certificate-authentication-1">certificate authentication</a></td><td class="printindex-index-section"><a href="#More-on-certificate-authentication">More on certificate authentication</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-certificate-requests">certificate requests</a></td><td class="printindex-index-section"><a href="#PKCS-10-certificate-requests">PKCS 10 certificate requests</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-certificate-revocation-lists">certificate revocation lists</a></td><td class="printindex-index-section"><a href="#PKIX-certificate-revocation-lists">PKIX certificate revocation lists</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-certificate-status">certificate status</a></td><td class="printindex-index-section"><a href="#OCSP-certificate-status-checking">OCSP certificate status checking</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-certificate-status-1">certificate status</a></td><td class="printindex-index-section"><a href="#OCSP-stapling">OCSP stapling</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-Certificate-status-request">Certificate status request</a></td><td class="printindex-index-section"><a href="#OCSP-status-request">OCSP status request</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-Certificate-verification">Certificate verification</a></td><td class="printindex-index-section"><a href="#Advanced-certificate-verification">Advanced certificate verification</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-certification">certification</a></td><td class="printindex-index-section"><a href="#Certification">Certification</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-certtool"><code>certtool</code></a></td><td class="printindex-index-section"><a href="#certtool-Invocation">certtool Invocation</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-certtool-help">certtool help</a></td><td class="printindex-index-section"><a href="#certtool-Invocation">certtool Invocation</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-channel-bindings">channel bindings</a></td><td class="printindex-index-section"><a href="#Channel-Bindings">Channel Bindings</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-ciphersuites">ciphersuites</a></td><td class="printindex-index-section"><a href="#Supported-ciphersuites">Supported ciphersuites</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-client-certificate-authentication">client certificate authentication</a></td><td class="printindex-index-section"><a href="#Client-Authentication">Client Authentication</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-CMS">CMS</a></td><td class="printindex-index-section"><a href="#Cryptographic-Message-Syntax-_002f-PKCS7">Cryptographic Message Syntax / PKCS7</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-compression-algorithms">compression algorithms</a></td><td class="printindex-index-section"><a href="#Compression-algorithms-and-the-record-layer">Compression algorithms and the record layer</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-contributing">contributing</a></td><td class="printindex-index-section"><a href="#Contributing">Contributing</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-credentials">credentials</a></td><td class="printindex-index-section"><a href="#Virtual-hosts-and-credentials">Virtual hosts and credentials</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-CRL">CRL</a></td><td class="printindex-index-section"><a href="#PKIX-certificate-revocation-lists">PKIX certificate revocation lists</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-cryptographic-message-syntax">cryptographic message syntax</a></td><td class="printindex-index-section"><a href="#Cryptographic-Message-Syntax-_002f-PKCS7">Cryptographic Message Syntax / PKCS7</a></td></tr>
<tr><td colspan="3"><hr></td></tr>
<tr><th id="Concept-Index_cp_letter-D">D</th></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-DANE">DANE</a></td><td class="printindex-index-section"><a href="#Verifying-a-certificate-using-DANE">Verifying a certificate using DANE</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-DANE-1">DANE</a></td><td class="printindex-index-section"><a href="#Certificate-verification">Certificate verification</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-danetool"><code>danetool</code></a></td><td class="printindex-index-section"><a href="#danetool-Invocation">danetool Invocation</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-danetool-help">danetool help</a></td><td class="printindex-index-section"><a href="#danetool-Invocation">danetool Invocation</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-deriving-keys">deriving keys</a></td><td class="printindex-index-section"><a href="#Deriving-keys-for-other-applications_002fprotocols">Deriving keys for other applications/protocols</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-digital-signatures">digital signatures</a></td><td class="printindex-index-section"><a href="#Digital-signatures">Digital signatures</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-DNSSEC">DNSSEC</a></td><td class="printindex-index-section"><a href="#Verifying-a-certificate-using-DANE">Verifying a certificate using DANE</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-DNSSEC-1">DNSSEC</a></td><td class="printindex-index-section"><a href="#Certificate-verification">Certificate verification</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-download">download</a></td><td class="printindex-index-section"><a href="#Downloading-and-installing">Downloading and installing</a></td></tr>
<tr><td colspan="3"><hr></td></tr>
<tr><th id="Concept-Index_cp_letter-E">E</th></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-Encrypted-keys">Encrypted keys</a></td><td class="printindex-index-section"><a href="#Managing-encrypted-keys">Managing encrypted keys</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-error-codes">error codes</a></td><td class="printindex-index-section"><a href="#Error-codes">Error codes</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-example-programs">example programs</a></td><td class="printindex-index-section"><a href="#GnuTLS-application-examples">GnuTLS application examples</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-examples">examples</a></td><td class="printindex-index-section"><a href="#GnuTLS-application-examples">GnuTLS application examples</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-exporting-keying-material">exporting keying material</a></td><td class="printindex-index-section"><a href="#Deriving-keys-for-other-applications_002fprotocols">Deriving keys for other applications/protocols</a></td></tr>
<tr><td colspan="3"><hr></td></tr>
<tr><th id="Concept-Index_cp_letter-F">F</th></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-False-Start">False Start</a></td><td class="printindex-index-section"><a href="#False-Start">False Start</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-FDL_002c-GNU-Free-Documentation-License">FDL, GNU Free Documentation License</a></td><td class="printindex-index-section"><a href="#Copying-Information">Copying Information</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-file-signing">file signing</a></td><td class="printindex-index-section"><a href="#Cryptographic-Message-Syntax-_002f-PKCS7">Cryptographic Message Syntax / PKCS7</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-fork">fork</a></td><td class="printindex-index-section"><a href="#Sessions-and-fork">Sessions and fork</a></td></tr>
<tr><td colspan="3"><hr></td></tr>
<tr><th id="Concept-Index_cp_letter-G">G</th></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-generating-parameters">generating parameters</a></td><td class="printindex-index-section"><a href="#Parameter-generation">Parameter generation</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-giovec_005ft">giovec_t</a></td><td class="printindex-index-section"><a href="#Common-types">Common types</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_005fdatum_005ft">gnutls_datum_t</a></td><td class="printindex-index-section"><a href="#Common-types">Common types</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_002dcli"><code>gnutls-cli</code></a></td><td class="printindex-index-section"><a href="#gnutls_002dcli-Invocation">gnutls-cli Invocation</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_002dcli-help">gnutls-cli help</a></td><td class="printindex-index-section"><a href="#gnutls_002dcli-Invocation">gnutls-cli Invocation</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_002dcli_002ddebug"><code>gnutls-cli-debug</code></a></td><td class="printindex-index-section"><a href="#gnutls_002dcli_002ddebug-Invocation">gnutls-cli-debug Invocation</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_002dcli_002ddebug-help">gnutls-cli-debug help</a></td><td class="printindex-index-section"><a href="#gnutls_002dcli_002ddebug-Invocation">gnutls-cli-debug Invocation</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_002dserv"><code>gnutls-serv</code></a></td><td class="printindex-index-section"><a href="#gnutls_002dserv-Invocation">gnutls-serv Invocation</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-gnutls_002dserv-help">gnutls-serv help</a></td><td class="printindex-index-section"><a href="#gnutls_002dserv-Invocation">gnutls-serv Invocation</a></td></tr>
<tr><td colspan="3"><hr></td></tr>
<tr><th id="Concept-Index_cp_letter-H">H</th></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-hacking">hacking</a></td><td class="printindex-index-section"><a href="#Contributing">Contributing</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-handshake-protocol">handshake protocol</a></td><td class="printindex-index-section"><a href="#The-TLS-Handshake-Protocol">The TLS Handshake Protocol</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-hardware-security-modules">hardware security modules</a></td><td class="printindex-index-section"><a href="#Smart-cards-and-HSMs">Smart cards and HSMs</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-hardware-tokens">hardware tokens</a></td><td class="printindex-index-section"><a href="#Smart-cards-and-HSMs">Smart cards and HSMs</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-hash-functions">hash functions</a></td><td class="printindex-index-section"><a href="#Hash-and-MAC-functions">Hash and MAC functions</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-heartbeat">heartbeat</a></td><td class="printindex-index-section"><a href="#HeartBeat">HeartBeat</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-HMAC-functions">HMAC functions</a></td><td class="printindex-index-section"><a href="#Hash-and-MAC-functions">Hash and MAC functions</a></td></tr>
<tr><td colspan="3"><hr></td></tr>
<tr><th id="Concept-Index_cp_letter-I">I</th></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-installation">installation</a></td><td class="printindex-index-section"><a href="#Downloading-and-installing">Downloading and installing</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-installation-1">installation</a></td><td class="printindex-index-section"><a href="#Installing-for-a-software-distribution">Installing for a software distribution</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-internal-architecture">internal architecture</a></td><td class="printindex-index-section"><a href="#Internal-architecture-of-GnuTLS">Internal architecture of GnuTLS</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-isolated-mode">isolated mode</a></td><td class="printindex-index-section"><a href="#Running-in-a-sandbox">Running in a sandbox</a></td></tr>
<tr><td colspan="3"><hr></td></tr>
<tr><th id="Concept-Index_cp_letter-K">K</th></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-key-extraction">key extraction</a></td><td class="printindex-index-section"><a href="#Deriving-keys-for-other-applications_002fprotocols">Deriving keys for other applications/protocols</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-Key-pinning">Key pinning</a></td><td class="printindex-index-section"><a href="#Verifying-a-certificate-using-trust-on-first-use-authentication">Verifying a certificate using trust on first use authentication</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-Key-pinning-1">Key pinning</a></td><td class="printindex-index-section"><a href="#Certificate-verification">Certificate verification</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-key-sizes">key sizes</a></td><td class="printindex-index-section"><a href="#Selecting-cryptographic-key-sizes">Selecting cryptographic key sizes</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-keying-material-exporters">keying material exporters</a></td><td class="printindex-index-section"><a href="#Deriving-keys-for-other-applications_002fprotocols">Deriving keys for other applications/protocols</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-kTLS-_0028Kernel-TLS_0029">kTLS (Kernel TLS)</a></td><td class="printindex-index-section"><a href="#kTLS-_0028Kernel-TLS_0029">kTLS (Kernel TLS)</a></td></tr>
<tr><td colspan="3"><hr></td></tr>
<tr><th id="Concept-Index_cp_letter-M">M</th></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-MAC-functions">MAC functions</a></td><td class="printindex-index-section"><a href="#Hash-and-MAC-functions">Hash and MAC functions</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-maximum-fragment-length">maximum fragment length</a></td><td class="printindex-index-section"><a href="#Maximum-fragment-length-negotiation">Maximum fragment length negotiation</a></td></tr>
<tr><td colspan="3"><hr></td></tr>
<tr><th id="Concept-Index_cp_letter-O">O</th></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-OCSP">OCSP</a></td><td class="printindex-index-section"><a href="#OCSP-certificate-status-checking">OCSP certificate status checking</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-OCSP-Functions">OCSP Functions</a></td><td class="printindex-index-section"><a href="#OCSP-API">OCSP API</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-OCSP-stapling">OCSP stapling</a></td><td class="printindex-index-section"><a href="#OCSP-stapling">OCSP stapling</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-OCSP-status-request">OCSP status request</a></td><td class="printindex-index-section"><a href="#OCSP-status-request">OCSP status request</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-ocsptool"><code>ocsptool</code></a></td><td class="printindex-index-section"><a href="#ocsptool-Invocation">ocsptool Invocation</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-ocsptool-help">ocsptool help</a></td><td class="printindex-index-section"><a href="#ocsptool-Invocation">ocsptool Invocation</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-Online-Certificate-Status-Protocol">Online Certificate Status Protocol</a></td><td class="printindex-index-section"><a href="#OCSP-certificate-status-checking">OCSP certificate status checking</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-Online-Certificate-Status-Protocol-1">Online Certificate Status Protocol</a></td><td class="printindex-index-section"><a href="#OCSP-stapling">OCSP stapling</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-OpenPGP-certificates">OpenPGP certificates</a></td><td class="printindex-index-section"><a href="#OpenPGP-certificates">OpenPGP certificates</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-OpenSSL">OpenSSL</a></td><td class="printindex-index-section"><a href="#Compatibility-with-the-OpenSSL-library">Compatibility with the OpenSSL library</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-OpenSSL-encrypted-keys">OpenSSL encrypted keys</a></td><td class="printindex-index-section"><a href="#Managing-encrypted-keys">Managing encrypted keys</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-overriding-algorithms">overriding algorithms</a></td><td class="printindex-index-section"><a href="#Overriding-algorithms">Overriding algorithms</a></td></tr>
<tr><td colspan="3"><hr></td></tr>
<tr><th id="Concept-Index_cp_letter-P">P</th></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-p11tool"><code>p11tool</code></a></td><td class="printindex-index-section"><a href="#p11tool-Invocation">p11tool Invocation</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-p11tool-help">p11tool help</a></td><td class="printindex-index-section"><a href="#p11tool-Invocation">p11tool Invocation</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-parameter-generation">parameter generation</a></td><td class="printindex-index-section"><a href="#Parameter-generation">Parameter generation</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-PCT">PCT</a></td><td class="printindex-index-section"><a href="#On-SSL-2-and-older-protocols">On SSL 2 and older protocols</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-PKCS-_002310">PKCS #10</a></td><td class="printindex-index-section"><a href="#PKCS-10-certificate-requests">PKCS 10 certificate requests</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-PKCS-_002311-tokens">PKCS #11 tokens</a></td><td class="printindex-index-section"><a href="#Smart-cards-and-HSMs">Smart cards and HSMs</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-PKCS-_002312">PKCS #12</a></td><td class="printindex-index-section"><a href="#Managing-encrypted-keys">Managing encrypted keys</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-PKCS-_00237">PKCS #7</a></td><td class="printindex-index-section"><a href="#Cryptographic-Message-Syntax-_002f-PKCS7">Cryptographic Message Syntax / PKCS7</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-PKCS-_00238">PKCS #8</a></td><td class="printindex-index-section"><a href="#Managing-encrypted-keys">Managing encrypted keys</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-post_002dhandshake-authentication">post-handshake authentication</a></td><td class="printindex-index-section"><a href="#TLS-1_002e3-re_002dauthentication-and-re_002dkey">TLS 1.3 re-authentication and re-key</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-Priority-strings">Priority strings</a></td><td class="printindex-index-section"><a href="#Priority-Strings">Priority Strings</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-PSK-authentication">PSK authentication</a></td><td class="printindex-index-section"><a href="#Authentication-using-PSK">Authentication using PSK</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-psktool"><code>psktool</code></a></td><td class="printindex-index-section"><a href="#psktool-Invocation">psktool Invocation</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-psktool-help">psktool help</a></td><td class="printindex-index-section"><a href="#psktool-Invocation">psktool Invocation</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-public-key-algorithms">public key algorithms</a></td><td class="printindex-index-section"><a href="#Public-key-algorithms">Public key algorithms</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-public-key-algorithms-1">public key algorithms</a></td><td class="printindex-index-section"><a href="#Cryptographic-Message-Syntax-_002f-PKCS7">Cryptographic Message Syntax / PKCS7</a></td></tr>
<tr><td colspan="3"><hr></td></tr>
<tr><th id="Concept-Index_cp_letter-R">R</th></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-random-numbers">random numbers</a></td><td class="printindex-index-section"><a href="#Random-number-generation">Random number generation</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-Raw-public_002dkeys">Raw public-keys</a></td><td class="printindex-index-section"><a href="#Raw-public_002dkeys">Raw public-keys</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-re_002dauthentication">re-authentication</a></td><td class="printindex-index-section"><a href="#TLS-1_002e2-re_002dauthentication">TLS 1.2 re-authentication</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-re_002dauthentication-1">re-authentication</a></td><td class="printindex-index-section"><a href="#TLS-1_002e3-re_002dauthentication-and-re_002dkey">TLS 1.3 re-authentication and re-key</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-re_002dkey">re-key</a></td><td class="printindex-index-section"><a href="#TLS-1_002e3-re_002dauthentication-and-re_002dkey">TLS 1.3 re-authentication and re-key</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-re_002dnegotiation">re-negotiation</a></td><td class="printindex-index-section"><a href="#TLS-1_002e2-re_002dauthentication">TLS 1.2 re-authentication</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-re_002dnegotiation-1">re-negotiation</a></td><td class="printindex-index-section"><a href="#TLS-1_002e3-re_002dauthentication-and-re_002dkey">TLS 1.3 re-authentication and re-key</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-record-padding">record padding</a></td><td class="printindex-index-section"><a href="#On-Record-Padding">On Record Padding</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-record-protocol">record protocol</a></td><td class="printindex-index-section"><a href="#The-TLS-record-protocol">The TLS record protocol</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-renegotiation">renegotiation</a></td><td class="printindex-index-section"><a href="#Safe-renegotiation">Safe renegotiation</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-reporting-bugs">reporting bugs</a></td><td class="printindex-index-section"><a href="#Bug-Reports">Bug Reports</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-resuming-sessions">resuming sessions</a></td><td class="printindex-index-section"><a href="#Resuming-Sessions">Resuming Sessions</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-resuming-sessions-1">resuming sessions</a></td><td class="printindex-index-section"><a href="#Session-resumption">Session resumption</a></td></tr>
<tr><td colspan="3"><hr></td></tr>
<tr><th id="Concept-Index_cp_letter-S">S</th></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-safe-renegotiation">safe renegotiation</a></td><td class="printindex-index-section"><a href="#Safe-renegotiation">Safe renegotiation</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-seccomp">seccomp</a></td><td class="printindex-index-section"><a href="#Running-in-a-sandbox">Running in a sandbox</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-Secure-RTP">Secure RTP</a></td><td class="printindex-index-section"><a href="#SRTP">SRTP</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-server-name-indication">server name indication</a></td><td class="printindex-index-section"><a href="#Server-name-indication">Server name indication</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-session-resumption">session resumption</a></td><td class="printindex-index-section"><a href="#Resuming-Sessions">Resuming Sessions</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-session-resumption-1">session resumption</a></td><td class="printindex-index-section"><a href="#Session-resumption">Session resumption</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-session-tickets">session tickets</a></td><td class="printindex-index-section"><a href="#Session-tickets">Session tickets</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-Smart-card-example">Smart card example</a></td><td class="printindex-index-section"><a href="#Client-using-a-smart-card-with-TLS">Client using a smart card with TLS</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-smart-cards">smart cards</a></td><td class="printindex-index-section"><a href="#Smart-cards-and-HSMs">Smart cards and HSMs</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-SRP-authentication">SRP authentication</a></td><td class="printindex-index-section"><a href="#Authentication-using-SRP">Authentication using SRP</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-srptool"><code>srptool</code></a></td><td class="printindex-index-section"><a href="#srptool-Invocation">srptool Invocation</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-srptool-help">srptool help</a></td><td class="printindex-index-section"><a href="#srptool-Invocation">srptool Invocation</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-SRTP">SRTP</a></td><td class="printindex-index-section"><a href="#SRTP">SRTP</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-SSH_002dstyle-authentication">SSH-style authentication</a></td><td class="printindex-index-section"><a href="#Verifying-a-certificate-using-trust-on-first-use-authentication">Verifying a certificate using trust on first use authentication</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-SSH_002dstyle-authentication-1">SSH-style authentication</a></td><td class="printindex-index-section"><a href="#Certificate-verification">Certificate verification</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-SSL-2">SSL 2</a></td><td class="printindex-index-section"><a href="#On-SSL-2-and-older-protocols">On SSL 2 and older protocols</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-Supplemental-data">Supplemental data</a></td><td class="printindex-index-section"><a href="#Extensions-and-Supplemental-Data">Extensions and Supplemental Data</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-symmetric-algorithms">symmetric algorithms</a></td><td class="printindex-index-section"><a href="#Symmetric-algorithms">Symmetric algorithms</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-symmetric-cryptography">symmetric cryptography</a></td><td class="printindex-index-section"><a href="#Symmetric-algorithms">Symmetric algorithms</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-symmetric-encryption-algorithms">symmetric encryption algorithms</a></td><td class="printindex-index-section"><a href="#Encryption-algorithms-used-in-the-record-layer">Encryption algorithms used in the record layer</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-System_002dspecific-keys">System-specific keys</a></td><td class="printindex-index-section"><a href="#Application_002dspecific-keys">Application-specific keys</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-System_002dwide-configuration">System-wide configuration</a></td><td class="printindex-index-section"><a href="#System_002dwide-configuration-of-the-library">System-wide configuration of the library</a></td></tr>
<tr><td colspan="3"><hr></td></tr>
<tr><th id="Concept-Index_cp_letter-T">T</th></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-thread-safety">thread safety</a></td><td class="printindex-index-section"><a href="#Thread-safety">Thread safety</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-tickets">tickets</a></td><td class="printindex-index-section"><a href="#Session-tickets">Session tickets</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-TLS-extensions">TLS extensions</a></td><td class="printindex-index-section"><a href="#TLS-Extensions">TLS Extensions</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-TLS-extensions-1">TLS extensions</a></td><td class="printindex-index-section"><a href="#Maximum-fragment-length-negotiation">Maximum fragment length negotiation</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-TLS-extensions-2">TLS extensions</a></td><td class="printindex-index-section"><a href="#Server-name-indication">Server name indication</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-TLS-extensions-3">TLS extensions</a></td><td class="printindex-index-section"><a href="#Session-tickets">Session tickets</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-TLS-extensions-4">TLS extensions</a></td><td class="printindex-index-section"><a href="#HeartBeat">HeartBeat</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-TLS-False-Start">TLS False Start</a></td><td class="printindex-index-section"><a href="#False-Start">False Start</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-TLS-layers">TLS layers</a></td><td class="printindex-index-section"><a href="#TLS-layers">TLS layers</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-TPM">TPM</a></td><td class="printindex-index-section"><a href="#Trusted-Platform-Module">Trusted Platform Module</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-tpmtool"><code>tpmtool</code></a></td><td class="printindex-index-section"><a href="#tpmtool-Invocation">tpmtool Invocation</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-tpmtool-help">tpmtool help</a></td><td class="printindex-index-section"><a href="#tpmtool-Invocation">tpmtool Invocation</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-transport-layer">transport layer</a></td><td class="printindex-index-section"><a href="#The-transport-layer">The transport layer</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-transport-protocol">transport protocol</a></td><td class="printindex-index-section"><a href="#The-transport-layer">The transport layer</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-Trust-on-first-use">Trust on first use</a></td><td class="printindex-index-section"><a href="#Verifying-a-certificate-using-trust-on-first-use-authentication">Verifying a certificate using trust on first use authentication</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-Trust-on-first-use-1">Trust on first use</a></td><td class="printindex-index-section"><a href="#Certificate-verification">Certificate verification</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-trusted-platform-module">trusted platform module</a></td><td class="printindex-index-section"><a href="#Trusted-Platform-Module">Trusted Platform Module</a></td></tr>
<tr><td colspan="3"><hr></td></tr>
<tr><th id="Concept-Index_cp_letter-U">U</th></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-upgrading">upgrading</a></td><td class="printindex-index-section"><a href="#Upgrading-from-previous-versions">Upgrading from previous versions</a></td></tr>
<tr><td colspan="3"><hr></td></tr>
<tr><th id="Concept-Index_cp_letter-V">V</th></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-verifying-certificate-paths">verifying certificate paths</a></td><td class="printindex-index-section"><a href="#Verifying-X_002e509-certificate-paths">Verifying X.509 certificate paths</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-verifying-certificate-paths-1">verifying certificate paths</a></td><td class="printindex-index-section"><a href="#Verifying-a-certificate-in-the-context-of-TLS-session">Verifying a certificate in the context of TLS session</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-verifying-certificate-paths-2">verifying certificate paths</a></td><td class="printindex-index-section"><a href="#Verifying-a-certificate-using-trust-on-first-use-authentication">Verifying a certificate using trust on first use authentication</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-verifying-certificate-paths-3">verifying certificate paths</a></td><td class="printindex-index-section"><a href="#Verifying-a-certificate-using-DANE">Verifying a certificate using DANE</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-verifying-certificate-with-pkcs11">verifying certificate with pkcs11</a></td><td class="printindex-index-section"><a href="#Verification-using-PKCS11">Verification using PKCS11</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-virtual-hosts">virtual hosts</a></td><td class="printindex-index-section"><a href="#Virtual-hosts-and-credentials">Virtual hosts and credentials</a></td></tr>
<tr><td colspan="3"><hr></td></tr>
<tr><th id="Concept-Index_cp_letter-X">X</th></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-X_002e509-certificate-name">X.509 certificate name</a></td><td class="printindex-index-section"><a href="#X_002e509-certificate-names">X.509 certificate names</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-X_002e509-certificates">X.509 certificates</a></td><td class="printindex-index-section"><a href="#X_002e509-certificates">X.509 certificates</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-X_002e509-distinguished-name">X.509 distinguished name</a></td><td class="printindex-index-section"><a href="#X_002e509-distinguished-names">X.509 distinguished names</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-X_002e509-extensions">X.509 extensions</a></td><td class="printindex-index-section"><a href="#X_002e509-extensions">X.509 extensions</a></td></tr>
<tr><td></td><td class="printindex-index-entry"><a href="#index-X_002e509-Functions">X.509 Functions</a></td><td class="printindex-index-section"><a href="#X509-certificate-API">X509 certificate API</a></td></tr>
<tr><td colspan="3"><hr></td></tr>
</table>
<table class="cp-letters-footer-printindex"><tr><th>Jump to: &nbsp; </th><td><a class="summary-letter-printindex" href="#Concept-Index_cp_letter-A"><b>A</b></a>
 &nbsp; 
<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-B"><b>B</b></a>
 &nbsp; 
<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-C"><b>C</b></a>
 &nbsp; 
<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-D"><b>D</b></a>
 &nbsp; 
<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-E"><b>E</b></a>
 &nbsp; 
<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-F"><b>F</b></a>
 &nbsp; 
<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-G"><b>G</b></a>
 &nbsp; 
<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-H"><b>H</b></a>
 &nbsp; 
<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-I"><b>I</b></a>
 &nbsp; 
<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-K"><b>K</b></a>
 &nbsp; 
<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-M"><b>M</b></a>
 &nbsp; 
<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-O"><b>O</b></a>
 &nbsp; 
<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-P"><b>P</b></a>
 &nbsp; 
<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-R"><b>R</b></a>
 &nbsp; 
<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-S"><b>S</b></a>
 &nbsp; 
<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-T"><b>T</b></a>
 &nbsp; 
<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-U"><b>U</b></a>
 &nbsp; 
<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-V"><b>V</b></a>
 &nbsp; 
<a class="summary-letter-printindex" href="#Concept-Index_cp_letter-X"><b>X</b></a>
 &nbsp; 
</td></tr></table>
</div>

</div>
</div>
<div class="footnotes-segment">
<hr>
<h4 class="footnotes-heading">Footnotes</h4>

<h5 class="footnote-body-heading"><a id="FOOT1" href="#DOCF1">(1)</a></h5>
<p>Needed
to use RFC6125 name comparison in internationalized domains.</p>
<h5 class="footnote-body-heading"><a id="FOOT2" href="#DOCF2">(2)</a></h5>
<p><a class="url" href="https://p11-glue.github.io/p11-glue/trust-module.html">https://p11-glue.github.io/p11-glue/trust-module.html</a></p>
<h5 class="footnote-body-heading"><a id="FOOT3" href="#DOCF3">(3)</a></h5>
<p>IETF, or Internet Engineering Task Force,
is a large open international community of network designers,
operators, vendors, and researchers concerned with the evolution of
the Internet architecture and the smooth operation of the Internet.
It is open to any interested individual.</p>
<h5 class="footnote-body-heading"><a id="FOOT4" href="#DOCF4">(4)</a></h5>
<p>In early versions of TLS compression was optionally
available as well. This is no longer the case in recent versions of the
protocol.</p>
<h5 class="footnote-body-heading"><a id="FOOT5" href="#DOCF5">(5)</a></h5>
<p>MAC stands for Message Authentication Code. It can be described as a keyed hash algorithm. See RFC2104.</p>
<h5 class="footnote-body-heading"><a id="FOOT6" href="#DOCF6">(6)</a></h5>
<p>See also the Server Name Indication extension on
<a class="ref" href="#serverind">serverind</a>.</p>
<h5 class="footnote-body-heading"><a id="FOOT7" href="#DOCF7">(7)</a></h5>
<p>See LDAP, IMAP etc.</p>
<h5 class="footnote-body-heading"><a id="FOOT8" href="#DOCF8">(8)</a></h5>
<p>see <a class="url" href="https://p11-glue.github.io/p11-glue/trust-module.html">https://p11-glue.github.io/p11-glue/trust-module.html</a>.</p>
<h5 class="footnote-body-heading"><a id="FOOT9" href="#DOCF9">(9)</a></h5>
<p>For example, OpenSC-supported cards.</p>
<h5 class="footnote-body-heading"><a id="FOOT10" href="#DOCF10">(10)</a></h5>
<p><a class="url" href="https://p11-glue.github.io/p11-glue/p11-kit.html">https://p11-glue.github.io/p11-glue/p11-kit.html</a></p>
<h5 class="footnote-body-heading"><a id="FOOT11" href="#DOCF11">(11)</a></h5>
<p>For
example when an open session is to be reinitialized, but the PIN is not available
to GnuTLS (e.g., it was entered at a pinpad).</p>
<h5 class="footnote-body-heading"><a id="FOOT12" href="#DOCF12">(12)</a></h5>
<p><a class="url" href="https://p11-glue.github.io/p11-glue/trust-module.html">https://p11-glue.github.io/p11-glue/trust-module.html</a></p>
<h5 class="footnote-body-heading"><a id="FOOT13" href="#DOCF13">(13)</a></h5>
<p>See
the &rsquo;Restricting the scope of CA certificates&rsquo; post at <a class="url" href="https://nmav.gnutls.org/2016/06/restricting-scope-of-ca-certificates.html">https://nmav.gnutls.org/2016/06/restricting-scope-of-ca-certificates.html</a></p>
<h5 class="footnote-body-heading"><a id="FOOT14" href="#DOCF14">(14)</a></h5>
<p><a class="url" href="https://github.com/google/chaps-linux">https://github.com/google/chaps-linux</a></p>
<h5 class="footnote-body-heading"><a id="FOOT15" href="#DOCF15">(15)</a></h5>
<p><a class="url" href="https://sourceforge.net/projects/opencryptoki/">https://sourceforge.net/projects/opencryptoki/</a></p>
<h5 class="footnote-body-heading"><a id="FOOT16" href="#DOCF16">(16)</a></h5>
<p>The first message in a <abbr class="acronym">TLS</abbr> handshake</p>
<h5 class="footnote-body-heading"><a id="FOOT17" href="#DOCF17">(17)</a></h5>
<p>On special systems
you could manually specify the locking system using
the function <a class="ref" href="#gnutls_005fglobal_005fset_005fmutex">gnutls_global_set_mutex</a> before calling any other
GnuTLS function. Setting mutexes manually is not recommended.</p>
<h5 class="footnote-body-heading"><a id="FOOT18" href="#DOCF18">(18)</a></h5>
<p>The original behavior of requiring explicit initialization can obtained by setting the
GNUTLS_NO_IMPLICIT_INIT environment variable to 1, or by using the macro GNUTLS_SKIP_GLOBAL_INIT
in a global section of your program &ndash;the latter works in systems with
support for weak symbols only.</p>
<h5 class="footnote-body-heading"><a id="FOOT19" href="#DOCF19">(19)</a></h5>
<p>A key of 128 bits or 16 bytes should be sufficient for this purpose.</p>
<h5 class="footnote-body-heading"><a id="FOOT20" href="#DOCF20">(20)</a></h5>
<p>It depends on the group in use.  Groups with
less bits are always faster, but the number of bits ties with the security
parameter.  See <a class="ref" href="#Selecting-cryptographic-key-sizes">Selecting cryptographic key sizes</a>
for the acceptable security levels.</p>
<h5 class="footnote-body-heading"><a id="FOOT21" href="#DOCF21">(21)</a></h5>
<p>See <a class="uref" href="https://www.lysator.liu.se/~nisse/nettle/">https://www.lysator.liu.se/~nisse/nettle/</a>.</p>
<h5 class="footnote-body-heading"><a id="FOOT22" href="#DOCF22">(22)</a></h5>
<p>See the nettle manual <a class="url" href="https://www.lysator.liu.se/~nisse/nettle/nettle.html">https://www.lysator.liu.se/~nisse/nettle/nettle.html</a></p>
<h5 class="footnote-body-heading"><a id="FOOT23" href="#DOCF23">(23)</a></h5>
<p>such as the
<code class="code">gnutls_certificate_credentials_t</code> structures</p>
<h5 class="footnote-body-heading"><a id="FOOT24" href="#DOCF24">(24)</a></h5>
<p>See
<a class="url" href="https://lists.gnu.org/archive/html/gnutls-devel/2011-02/msg00079.html">https://lists.gnu.org/archive/html/gnutls-devel/2011-02/msg00079.html</a>.</p>
<h5 class="footnote-body-heading"><a id="FOOT25" href="#DOCF25">(25)</a></h5>
<p>Check <a class="url" href="https://home.gna.org/cryptodev-linux/">https://home.gna.org/cryptodev-linux/</a>
for the Linux kernel implementation of <code class="code">/dev/crypto</code>.</p>
<h5 class="footnote-body-heading"><a id="FOOT26" href="#DOCF26">(26)</a></h5>
<p>see <a class="uref" href="https://www.kernel.org/doc/html/latest/process/coding-style.html">https://www.kernel.org/doc/html/latest/process/coding-style.html</a>.</p>
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