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<html lang="en">
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<title>GNU TLS 1.4.4</title>
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<h1 class="settitle">GNU TLS 1.4.4</h1>
<div class="contents">
<h2>Table of Contents</h2>
<ul>
<li><a name="toc_Top" href="#Top">GNU TLS</a>
<li><a name="toc_Preface" href="#Preface">1 Preface</a>
<li><a name="toc_The-Library" href="#The-Library">2 The Library</a>
<ul>
<li><a href="#General-Idea">2.1 General Idea</a>
<li><a href="#Error-handling">2.2 Error handling</a>
<li><a href="#Memory-handling">2.3 Memory handling</a>
<li><a href="#Callback-functions">2.4 Callback functions</a>
</li></ul>
<li><a name="toc_Introduction-to-TLS" href="#Introduction-to-TLS">3 Introduction to <acronym>TLS</acronym></a>
<ul>
<li><a href="#TLS-layers">3.1 TLS layers</a>
<li><a href="#The-transport-layer">3.2 The transport layer</a>
<li><a href="#The-TLS-record-protocol">3.3 The TLS record protocol</a>
<ul>
<li><a href="#Encryption-algorithms-used-in-the-record-layer">3.3.1 Encryption algorithms used in the record layer</a>
<li><a href="#Compression-algorithms-used-in-the-record-layer">3.3.2 Compression algorithms used in the record layer</a>
<li><a href="#Weaknesses-and-countermeasures">3.3.3 Weaknesses and countermeasures</a>
</li></ul>
<li><a href="#The-TLS-Alert-Protocol">3.4 The TLS Alert Protocol</a>
<li><a href="#The-TLS-Handshake-Protocol">3.5 The TLS Handshake Protocol</a>
<ul>
<li><a href="#The-TLS-Handshake-Protocol">3.5.1 TLS cipher suites</a>
<li><a href="#The-TLS-Handshake-Protocol">3.5.2 Client authentication</a>
<li><a href="#The-TLS-Handshake-Protocol">3.5.3 Resuming Sessions</a>
<li><a href="#The-TLS-Handshake-Protocol">3.5.4 Resuming internals</a>
</li></ul>
<li><a href="#TLS-Extensions">3.6 TLS Extensions</a>
<ul>
<li><a href="#TLS-Extensions">3.6.1 Maximum fragment length negotiation</a>
<li><a href="#TLS-Extensions">3.6.2 Server name indication</a>
</li></ul>
<li><a href="#On-SSL-2-and-older-protocols">3.7 On SSL 2 and older protocols</a>
</li></ul>
<li><a name="toc_Authentication-methods" href="#Authentication-methods">4 Authentication methods</a>
<ul>
<li><a href="#Certificate-authentication">4.1 Certificate authentication</a>
<ul>
<li><a href="#Certificate-authentication">4.1.1 Authentication using <acronym>X.509</acronym> certificates</a>
<li><a href="#Certificate-authentication">4.1.2 Authentication using <acronym>OpenPGP</acronym> keys</a>
<li><a href="#Certificate-authentication">4.1.3 Using certificate authentication</a>
</li></ul>
<li><a href="#Anonymous-authentication">4.2 Anonymous authentication</a>
<li><a href="#Authentication-using-SRP">4.3 Authentication using <acronym>SRP</acronym></a>
<li><a href="#Authentication-using-PSK">4.4 Authentication using <acronym>PSK</acronym></a>
<li><a href="#Authentication-and-credentials">4.5 Authentication and credentials</a>
<li><a href="#Parameters-stored-in-credentials">4.6 Parameters stored in credentials</a>
</li></ul>
<li><a name="toc_More-on-certificate-authentication" href="#More-on-certificate-authentication">5 More on certificate authentication</a>
<ul>
<li><a href="#The-X_002e509-trust-model">5.1 The <acronym>X.509</acronym> trust model</a>
<ul>
<li><a href="#X_002e509-certificates">5.1.1 <acronym>X.509</acronym> certificates</a>
<li><a href="#Verifying-X_002e509-certificate-paths">5.1.2 Verifying <acronym>X.509</acronym> certificate paths</a>
<li><a href="#PKCS-_002310-certificate-requests">5.1.3 <acronym>PKCS</acronym> #10 certificate requests</a>
<li><a href="#PKCS-_002312-structures">5.1.4 <acronym>PKCS</acronym> #12 structures</a>
</li></ul>
<li><a href="#The-OpenPGP-trust-model">5.2 The <acronym>OpenPGP</acronym> trust model</a>
<ul>
<li><a href="#The-OpenPGP-trust-model">5.2.1 <acronym>OpenPGP</acronym> keys</a>
<li><a href="#The-OpenPGP-trust-model">5.2.2 Verifying an <acronym>OpenPGP</acronym> key</a>
</li></ul>
<li><a href="#Digital-signatures">5.3 Digital signatures</a>
<ul>
<li><a href="#Digital-signatures">5.3.1 Supported algorithms</a>
<li><a href="#Digital-signatures">5.3.2 Trading security for interoperability</a>
</li></ul>
</li></ul>
<li><a name="toc_How-to-use-TLS-in-application-protocols" href="#How-to-use-TLS-in-application-protocols">6 How to use <acronym>TLS</acronym> in application protocols</a>
<ul>
<li><a href="#Separate-ports">6.1 Separate ports</a>
<li><a href="#Upward-negotiation">6.2 Upward negotiation</a>
</li></ul>
<li><a name="toc_How-to-use-GnuTLS-in-applications" href="#How-to-use-GnuTLS-in-applications">7 How to use <acronym>GnuTLS</acronym> in applications</a>
<ul>
<li><a href="#Preparation">7.1 Preparation</a>
<ul>
<li><a href="#Headers">7.1.1 Headers</a>
<li><a href="#Version-check">7.1.2 Version check</a>
<li><a href="#Building-the-source">7.1.3 Building the source</a>
</li></ul>
<li><a href="#Multi_002dthreaded-applications">7.2 Multi-threaded applications</a>
<li><a href="#Client-examples">7.3 Client examples</a>
<ul>
<li><a href="#Simple-client-example-with-anonymous-authentication">7.3.1 Simple client example with anonymous authentication</a>
<li><a href="#Simple-client-example-with-X_002e509-certificate-support">7.3.2 Simple client example with <acronym>X.509</acronym> certificate support</a>
<li><a href="#Obtaining-session-information">7.3.3 Obtaining session information</a>
<li><a href="#Verifying-peer_0027s-certificate">7.3.4 Verifying peer's certificate</a>
<li><a href="#Using-a-callback-to-select-the-certificate-to-use">7.3.5 Using a callback to select the certificate to use</a>
<li><a href="#Client-with-Resume-capability-example">7.3.6 Client with Resume capability example</a>
<li><a href="#Simple-client-example-with-SRP-authentication">7.3.7 Simple client example with <acronym>SRP</acronym> authentication</a>
</li></ul>
<li><a href="#Server-examples">7.4 Server examples</a>
<ul>
<li><a href="#Echo-Server-with-X_002e509-authentication">7.4.1 Echo Server with <acronym>X.509</acronym> authentication</a>
<li><a href="#Echo-Server-with-X_002e509-authentication-II">7.4.2 Echo Server with <acronym>X.509</acronym> authentication II</a>
<li><a href="#Echo-Server-with-OpenPGP-authentication">7.4.3 Echo Server with <acronym>OpenPGP</acronym> authentication</a>
<li><a href="#Echo-Server-with-SRP-authentication">7.4.4 Echo Server with <acronym>SRP</acronym> authentication</a>
<li><a href="#Echo-Server-with-anonymous-authentication">7.4.5 Echo Server with anonymous authentication</a>
</li></ul>
<li><a href="#Miscellaneous-examples">7.5 Miscellaneous examples</a>
<ul>
<li><a href="#Checking-for-an-alert">7.5.1 Checking for an alert</a>
<li><a href="#X_002e509-certificate-parsing-example">7.5.2 <acronym>X.509</acronym> certificate parsing example</a>
<li><a href="#Certificate-request-generation">7.5.3 Certificate request generation</a>
<li><a href="#PKCS-_002312-structure-generation">7.5.4 <acronym>PKCS</acronym> #12 structure generation</a>
</li></ul>
<li><a href="#Compatibility-with-the-OpenSSL-library">7.6 Compatibility with the OpenSSL library</a>
</li></ul>
<li><a name="toc_Included-programs" href="#Included-programs">8 Included programs</a>
<ul>
<li><a href="#Invoking-srptool">8.1 Invoking srptool</a>
<li><a href="#Invoking-gnutls_002dcli">8.2 Invoking gnutls-cli</a>
<li><a href="#Invoking-gnutls_002dcli_002ddebug">8.3 Invoking gnutls-cli-debug</a>
<li><a href="#Invoking-gnutls_002dserv">8.4 Invoking gnutls-serv</a>
<li><a href="#Invoking-certtool">8.5 Invoking certtool</a>
</li></ul>
<li><a name="toc_Function-reference" href="#Function-reference">9 Function reference</a>
<ul>
<li><a href="#Core-functions">9.1 Core functions</a>
<li><a href="#X_002e509-certificate-functions">9.2 <acronym>X.509</acronym> certificate functions</a>
<li><a href="#GnuTLS_002dextra-functions">9.3 <acronym>GnuTLS-extra</acronym> functions</a>
<li><a href="#OpenPGP-functions">9.4 <acronym>OpenPGP</acronym> functions</a>
<li><a href="#TLS-Inner-Application-_0028TLS_002fIA_0029-functions">9.5 <acronym>TLS</acronym> Inner Application (<acronym>TLS/IA</acronym>) functions</a>
<li><a href="#Error-codes-and-descriptions">9.6 Error codes and descriptions</a>
</li></ul>
<li><a name="toc_Certificate-to-XML-convertion-functions" href="#Certificate-to-XML-convertion-functions">10 Certificate to <acronym>XML</acronym> convertion functions</a>
<ul>
<li><a href="#An-X_002e509-certificate">10.1 An <acronym>X.509</acronym> certificate</a>
<li><a href="#An-OpenPGP-key">10.2 An <acronym>OpenPGP</acronym> key</a>
</li></ul>
<li><a name="toc_All-the-supported-ciphersuites-in-GnuTLS" href="#All-the-supported-ciphersuites-in-GnuTLS">11 All the supported ciphersuites in <acronym>GnuTLS</acronym></a>
<li><a name="toc_Internal-architecture-of-GnuTLS" href="#Internal-architecture-of-GnuTLS">12 Internal architecture of GnuTLS</a>
<ul>
<li><a href="#Internal-architecture-of-GnuTLS">12.1 The TLS protocol</a>
<li><a href="#Internal-architecture-of-GnuTLS">12.2 TLS Handshake protocol</a>
<li><a href="#Internal-architecture-of-GnuTLS">12.3 TLS authentication methods</a>
<li><a href="#Internal-architecture-of-GnuTLS">12.4 TLS Extension handling</a>
<li><a href="#Internal-architecture-of-GnuTLS">12.5 Certificate handling</a>
</li></ul>
<li><a name="toc_Copying-This-Manual" href="#Copying-This-Manual">Appendix A Copying This Manual</a>
<ul>
<li><a href="#GNU-Free-Documentation-License">A.1 GNU Free Documentation License</a>
<ul>
<li><a href="#GNU-Free-Documentation-License">A.1.1 ADDENDUM: How to use this License for your documents</a>
</li></ul>
</li></ul>
<li><a name="toc_Concept-Index" href="#Concept-Index">Concept Index</a>
<li><a name="toc_Function-and-Data-Index" href="#Function-and-Data-Index">Function and Data Index</a>
<li><a name="toc_Bibliography" href="#Bibliography">Bibliography</a>
</li></ul>
</div>
<div class="node">
<p><hr>
<a name="Top"></a>
Next: <a rel="next" accesskey="n" href="#Preface">Preface</a>,
Up: <a rel="up" accesskey="u" href="#dir">(dir)</a>
</div>
<h2 class="unnumbered">GNU TLS</h2>
<p>This manual is last updated 21 March 2006 for version
1.4.4 of GNU TLS.
<p>Copyright (C) 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
<blockquote>
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.2
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”.
</blockquote>
<ul class="menu">
<li><a accesskey="1" href="#Preface">Preface</a>
<li><a accesskey="2" href="#The-Library">The Library</a>
<li><a accesskey="3" href="#Introduction-to-TLS">Introduction to TLS</a>
<li><a accesskey="4" href="#Authentication-methods">Authentication methods</a>
<li><a accesskey="5" href="#More-on-certificate-authentication">More on certificate authentication</a>
<li><a accesskey="6" href="#How-to-use-TLS-in-application-protocols">How to use TLS in application protocols</a>
<li><a accesskey="7" href="#How-to-use-GnuTLS-in-applications">How to use GnuTLS in applications</a>
<li><a accesskey="8" href="#Included-programs">Included programs</a>
<li><a accesskey="9" href="#Function-reference">Function reference</a>
<li><a href="#Certificate-to-XML-convertion-functions">Certificate to XML convertion functions</a>
<li><a href="#All-the-supported-ciphersuites-in-GnuTLS">All the supported ciphersuites in GnuTLS</a>
<li><a href="#Internal-architecture-of-GnuTLS">Internal architecture of GnuTLS</a>
<li><a href="#Copying-This-Manual">Copying This Manual</a>
<li><a href="#Concept-Index">Concept Index</a>
<li><a href="#Function-and-Data-Index">Function and Data Index</a>
<!-- * @mybibnode{}:: -->
<li><a href="#Bibliography">Bibliography</a>
</ul>
<div class="node">
<p><hr>
<a name="Preface"></a>
Next: <a rel="next" accesskey="n" href="#The-Library">The Library</a>,
Previous: <a rel="previous" accesskey="p" href="#Top">Top</a>,
Up: <a rel="up" accesskey="u" href="#Top">Top</a>
</div>
<h2 class="chapter">1 Preface</h2>
<p>This document tries to demonstrate and explain the <acronym>GnuTLS</acronym>
library API. A brief introduction to the protocols and the technology
involved, is also included so that an application programmer can
better understand the <acronym>GnuTLS</acronym> purpose and actual offerings.
Even if <acronym>GnuTLS</acronym> 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 he
risks to offer just a false sense of security. Security and the
network security terms are very general terms even for computer
software thus cannot be easily restricted to a single cryptographic
library. For that reason, do not consider a program secure just
because it uses <acronym>GnuTLS</acronym>; there are several ways to compromise
a program or a communication line and <acronym>GnuTLS</acronym> only helps with
some of them.
<p>Although this document tries to be self contained, basic network
programming and PKI knowlegde is assumed in most of it. A good introduction
to networking can be found in <!-- %**else if -->
[STEVENS] (See <a href="#Bibliography">STEVENS</a>.)
and for
Public Key Infrastructure in <!-- %**else if -->
[GUTPKI] (See <a href="#Bibliography">GUTPKI</a>.)
.
<p><a name="Availability"></a>
<p>Updated versions of the <acronym>GnuTLS</acronym> software and this document
will be available from <a href="http://www.gnutls.org/">http://www.gnutls.org/</a> and
<a href="http://www.gnu.org/software/gnutls/">http://www.gnu.org/software/gnutls/</a>.
<div class="node">
<p><hr>
<a name="The-Library"></a>
Next: <a rel="next" accesskey="n" href="#Introduction-to-TLS">Introduction to TLS</a>,
Previous: <a rel="previous" accesskey="p" href="#Preface">Preface</a>,
Up: <a rel="up" accesskey="u" href="#Top">Top</a>
</div>
<h2 class="chapter">2 The Library</h2>
<p>In brief <acronym>GnuTLS</acronym> 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>Technically <acronym>GnuTLS</acronym> is a portable ANSI C based library which
implements the TLS 1.1 and SSL 3.0 protocols (See <a href="#Introduction-to-TLS">Introduction to TLS</a>, for a more detailed description of the protocols), accompanied
with the required framework for authentication and public key
infrastructure. The library is available under the GNU Lesser GPL
license<a rel="footnote" href="#fn-1" name="fnd-1"><sup>1</sup></a>. Important features of the <acronym>GnuTLS</acronym> library
include:
<ul>
<li>Support for TLS 1.0, TLS 1.1, and SSL 3.0 protocols.
<li>Support for both <acronym>X.509</acronym> and <acronym>OpenPGP</acronym> certificates.
<li>Support for handling and verification of certificates.
<li>Support for <acronym>SRP</acronym> for TLS authentication.
<li>Support for <acronym>PSK</acronym> for TLS authentication.
<li>Support for TLS Extension mechanism.
<li>Support for TLS Compression Methods.
</ul>
<p>Additionally <acronym>GnuTLS</acronym> provides a limited emulation API for the
widely used OpenSSL<a rel="footnote" href="#fn-2" name="fnd-2"><sup>2</sup></a> library,
to ease integration with existing applications.
<p><acronym>GnuTLS</acronym> consists of three independent parts, namely the “TLS
protocol part”, the “Certificate part”, and the “Crypto backend”
part. The `TLS protocol part' is the actual protocol implementation,
and is entirely implemented within the <acronym>GnuTLS</acronym> library. The
`Certificate part' consists of the certificate parsing, and
verification functions which is partially implemented in the
<acronym>GnuTLS</acronym> library. The
<acronym>Libtasn1</acronym><a rel="footnote" href="#fn-3" name="fnd-3"><sup>3</sup></a>,
a library which offers <acronym>ASN.1</acronym> parsing capabilities, is used
for the <acronym>X.509</acronym> certificate parsing functions, and
<acronym>Opencdk</acronym><a rel="footnote" href="#fn-4" name="fnd-4"><sup>4</sup></a>
is used for the <acronym>OpenPGP</acronym> key support in <acronym>GnuTLS</acronym>.
The “Crypto backend” is provided by the
<acronym>Libgcrypt</acronym><a rel="footnote" href="#fn-5" name="fnd-5"><sup>5</sup></a>
library.
<p>In order to ease integration in embedded systems, parts of the
<acronym>GnuTLS</acronym> library can be disabled at compile time. That way a
small library, with the required features, can be generated.
<ul class="menu">
<li><a accesskey="1" href="#General-Idea">General Idea</a>
<li><a accesskey="2" href="#Error-handling">Error handling</a>
<li><a accesskey="3" href="#Memory-handling">Memory handling</a>
<li><a accesskey="4" href="#Callback-functions">Callback functions</a>
</ul>
<div class="node">
<p><hr>
<a name="General-Idea"></a>
Next: <a rel="next" accesskey="n" href="#Error-handling">Error handling</a>,
Up: <a rel="up" accesskey="u" href="#The-Library">The Library</a>
</div>
<h3 class="section">2.1 General Idea</h3>
<p>A brief description of how <acronym>GnuTLS</acronym> works internally is shown
at the figure below. This section may be easier to understand after
having seen the examples (see <a href="#examples">examples</a>).
<div class="block-image"><img src="internals.png" alt="internals.png"></div>
<p>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, and some structures needed for the <acronym>ASN.1</acronym> parser. This structure
is never modified by any <acronym>GnuTLS</acronym> function, except for the
deinitialization function which frees all memory allocated in the
global structure and is called after the program has permanently
finished using <acronym>GnuTLS</acronym>.
<p>The credentials structure is used by some authentication methods, such
as certificate authentication (see <a href="#Certificate-Authentication">Certificate Authentication</a>). A
credentials structure may contain certificates, private keys,
temporary parameters for diffie hellman or RSA key exchange, and other
stuff that may be shared between several TLS sessions.
<p>This structure should be initialized using the appropriate
initialization functions. For example an application which uses
certificate authentication would probably initialize the credentials,
using the appropriate functions, and put its trusted certificates in
this structure. The next step is to associate the credentials
structure with each <acronym>TLS</acronym> session.
<p>A <acronym>GnuTLS</acronym> session contains all the required stuff for a
session to handle one secure connection. This session calls directly
to the transport layer functions, in order to communicate with the
peer. Every session has a unique session ID shared with the peer.
<p>Since TLS sessions can be resumed, servers would probably need a
database backend to hold the session's parameters. Every
<acronym>GnuTLS</acronym> session after a successful handshake calls the
appropriate backend function (See <a href="#resume">resume</a>, for information on
initialization) to store the newly negotiated session. The session
database is examined by the server just after having received the
client hello<a rel="footnote" href="#fn-6" name="fnd-6"><sup>6</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.
<div class="node">
<p><hr>
<a name="Error-handling"></a>
Next: <a rel="next" accesskey="n" href="#Memory-handling">Memory handling</a>,
Previous: <a rel="previous" accesskey="p" href="#General-Idea">General Idea</a>,
Up: <a rel="up" accesskey="u" href="#The-Library">The Library</a>
</div>
<h3 class="section">2.2 Error handling</h3>
<p>In <acronym>GnuTLS</acronym> most functions return an integer type as a result. In
almost all cases a zero or a positive number means success, and a
negative number indicates failure, or a situation that some action has
to be taken. Thus negative error codes may be fatal or not.
<p>Fatal errors terminate the connection immediately and further sends
and receives will be disallowed. An example of a fatal error code is
<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>GNUTLS_E_REHANDSHAKE</code> returned by <a 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 href="#gnutls_005ferror_005fis_005ffatal">gnutls_error_is_fatal</a>.
<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's
reference. See <a href="#Error-Codes">Error Codes</a>, for all the error codes.
<div class="node">
<p><hr>
<a name="Memory-handling"></a>
Next: <a rel="next" accesskey="n" href="#Callback-functions">Callback functions</a>,
Previous: <a rel="previous" accesskey="p" href="#Error-handling">Error handling</a>,
Up: <a rel="up" accesskey="u" href="#The-Library">The Library</a>
</div>
<h3 class="section">2.3 Memory handling</h3>
<p><acronym>GnuTLS</acronym> internally handles heap allocated objects
differently, depending on the sensitivity of the data they
contain. However for performance reasons, the default memory functions
do not overwrite sensitive data from memory, nor protect such objects
from being written to the swap. In order to change the default
behavior the <a href="#gnutls_005fglobal_005fset_005fmem_005ffunctions">gnutls_global_set_mem_functions</a> function is
available which can be used to set other memory handlers than the
defaults.
<p>The <acronym>Libgcrypt</acronym> library on which <acronym>GnuTLS</acronym> depends, has such
secure memory allocation functions available. These should be used in
cases where even the system's swap memory is not considered
secure. See the documentation of <acronym>Libgcrypt</acronym> for more
information.
<div class="node">
<p><hr>
<a name="Callback-functions"></a>
Previous: <a rel="previous" accesskey="p" href="#Memory-handling">Memory handling</a>,
Up: <a rel="up" accesskey="u" href="#The-Library">The Library</a>
</div>
<h3 class="section">2.4 Callback functions</h3>
<p><a name="index-Callback-functions-1"></a>
There are several cases where <acronym>GnuTLS</acronym> may need some out of
band input from your program. This is now implemented using some
callback functions, which your program is expected to register.
<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.
<ul>
<li><a href="#gnutls_005ftransport_005fset_005fpush_005ffunction">gnutls_transport_set_push_function</a>
<li><a href="#gnutls_005ftransport_005fset_005fpull_005ffunction">gnutls_transport_set_pull_function</a>
</ul>
<p>Other callback functions such as the one set by
<a href="#gnutls_005fsrp_005fset_005fserver_005fcredentials_005ffunction">gnutls_srp_set_server_credentials_function</a>, may require more
complicated input, including data to be allocated. These callbacks
should allocate and free memory using the functions shown below.
<ul>
<li><a href="#gnutls_005fmalloc">gnutls_malloc</a>
<li><a href="#gnutls_005ffree">gnutls_free</a>
</ul>
<div class="node">
<p><hr>
<a name="Introduction-to-TLS"></a>
Next: <a rel="next" accesskey="n" href="#Authentication-methods">Authentication methods</a>,
Previous: <a rel="previous" accesskey="p" href="#The-Library">The Library</a>,
Up: <a rel="up" accesskey="u" href="#Top">Top</a>
</div>
<h2 class="chapter">3 Introduction to <acronym>TLS</acronym></h2>
<p><acronym>TLS</acronym> stands for “Transport Layer Security” and is the
successor of SSL, the Secure Sockets Layer protocol <!-- %**else if -->
[SSL3] (See <a href="#Bibliography">SSL3</a>.)
designed by Netscape. <acronym>TLS</acronym> is an Internet
protocol, defined by <acronym>IETF</acronym><a rel="footnote" href="#fn-7" name="fnd-7"><sup>7</sup></a>, described in
<acronym>RFC</acronym> 2246 and also in <!-- %**else if -->
[RESCOLA] (See <a href="#Bibliography">RESCOLA</a>.)
. The protocol provides
confidentiality, and authentication layers over any reliable transport
layer. The description, below, refers to <acronym>TLS</acronym> 1.0 but also
applies to <acronym>TLS</acronym> 1.1 <!-- %**else if -->
[RFC4346] (See <a href="#Bibliography">RFC4346</a>.)
and <acronym>SSL</acronym> 3.0, since the
differences of these protocols are minor. Older protocols such as
<acronym>SSL</acronym> 2.0 are not discussed nor implemented in
<acronym>GnuTLS</acronym> since they are not considered secure today.
<ul class="menu">
<li><a accesskey="1" href="#TLS-layers">TLS layers</a>
<li><a accesskey="2" href="#The-transport-layer">The transport layer</a>
<li><a accesskey="3" href="#The-TLS-record-protocol">The TLS record protocol</a>
<li><a accesskey="4" href="#The-TLS-Alert-Protocol">The TLS Alert Protocol</a>
<li><a accesskey="5" href="#The-TLS-Handshake-Protocol">The TLS Handshake Protocol</a>
<li><a accesskey="6" href="#TLS-Extensions">TLS Extensions</a>
<li><a accesskey="7" href="#On-SSL-2-and-older-protocols">On SSL 2 and older protocols</a>
</ul>
<div class="node">
<p><hr>
<a name="TLS-layers"></a>
Next: <a rel="next" accesskey="n" href="#The-transport-layer">The transport layer</a>,
Up: <a rel="up" accesskey="u" href="#Introduction-to-TLS">Introduction to TLS</a>
</div>
<h3 class="section">3.1 TLS layers</h3>
<p><a name="index-TLS-Layers-2"></a>
<acronym>TLS</acronym> 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, data
authenticity, and optionally compression.
<p>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 href="#The-Alert-Protocol">The Alert Protocol</a>, for more information. The
alert protocol is above the record protocol.
<p>The Handshake protocol is responsible for the security parameters'
negotiation, the initial key exchange and authentication. See <a href="#The-Handshake-Protocol">The Handshake Protocol</a>, for more information about the handshake
protocol. The protocol layering in TLS is shown in the figure below.
<div class="block-image"><img src="layers.png" alt="layers.png"></div>
<div class="node">
<p><hr>
<a name="The-transport-layer"></a>
Next: <a rel="next" accesskey="n" href="#The-TLS-record-protocol">The TLS record protocol</a>,
Previous: <a rel="previous" accesskey="p" href="#TLS-layers">TLS layers</a>,
Up: <a rel="up" accesskey="u" href="#Introduction-to-TLS">Introduction to TLS</a>
</div>
<h3 class="section">3.2 The transport layer</h3>
<p><a name="index-Transport-protocol-3"></a>
<acronym>TLS</acronym> is not limited to one transport layer, it can be used
above any transport layer, as long as it is a reliable one. A set of
functions is provided and their purpose is to load to <acronym>GnuTLS</acronym> the
required callbacks to access the transport layer.
<ul>
<li><a href="#gnutls_005ftransport_005fset_005fpush_005ffunction">gnutls_transport_set_push_function</a>
<li><a href="#gnutls_005ftransport_005fset_005fpull_005ffunction">gnutls_transport_set_pull_function</a>
<li><a href="#gnutls_005ftransport_005fset_005fptr">gnutls_transport_set_ptr</a>
<li><a href="#gnutls_005ftransport_005fset_005flowat">gnutls_transport_set_lowat</a>
</ul>
<p>These functions accept a callback function as a parameter. The
callback functions should return the number of bytes written, or -1 on
error and should set <code>errno</code> appropriately.
<p><acronym>GnuTLS</acronym> currently only interprets the EINTR and EAGAIN errno
values and returns the corresponding <acronym>GnuTLS</acronym> error codes
<code>GNUTLS_E_INTERRUPTED</code> and <code>GNUTLS_E_AGAIN</code>. These values
are usually returned by interrupted system calls, or when non blocking
IO is used. All <acronym>GnuTLS</acronym> functions can be resumed (called
again), if any of these error codes is returned. The error codes
above refer to the system call, not the <acronym>GnuTLS</acronym> function,
since signals do not interrupt <acronym>GnuTLS</acronym>' functions.
<p>For non blocking sockets or other custom made pull/push functions
the <a href="#gnutls_005ftransport_005fset_005flowat">gnutls_transport_set_lowat</a> must be called, with a zero
low water mark value.
<p>By default, if the transport functions are not set, <acronym>GnuTLS</acronym>
will use the Berkeley Sockets functions. In this case
<acronym>GnuTLS</acronym> will use some hacks in order for <code>select</code> to
work, thus making it easy to add <acronym>TLS</acronym> support to existing
TCP/IP servers.
<div class="node">
<p><hr>
<a name="The-TLS-record-protocol"></a>
Next: <a rel="next" accesskey="n" href="#The-TLS-Alert-Protocol">The TLS Alert Protocol</a>,
Previous: <a rel="previous" accesskey="p" href="#The-transport-layer">The transport layer</a>,
Up: <a rel="up" accesskey="u" href="#Introduction-to-TLS">Introduction to TLS</a>
</div>
<h3 class="section">3.3 The TLS record protocol</h3>
<p><a name="index-Record-protocol-4"></a>
The Record protocol is the secure communications provider. Its purpose
is to encrypt, authenticate and —optionally— compress packets.
The following functions are available:
<dl>
<dt><a href="#gnutls_005frecord_005fsend">gnutls_record_send</a>:<dd>To send a record packet (with application data).
<br><dt><a href="#gnutls_005frecord_005frecv">gnutls_record_recv</a>:<dd>To receive a record packet (with application data).
<br><dt><a href="#gnutls_005frecord_005fget_005fdirection">gnutls_record_get_direction</a>:<dd>To get the direction of the last interrupted function call.
</dl>
<p>As you may have already noticed, the functions which access the Record
protocol, are quite limited, given the importance of this protocol in
<acronym>TLS</acronym>. This is because the Record protocol's parameters are
all set by the Handshake protocol.
<p>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.
<ul class="menu">
<li><a accesskey="1" href="#Encryption-algorithms-used-in-the-record-layer">Encryption algorithms used in the record layer</a>
<li><a accesskey="2" href="#Compression-algorithms-used-in-the-record-layer">Compression algorithms used in the record layer</a>
<li><a accesskey="3" href="#Weaknesses-and-countermeasures">Weaknesses and countermeasures</a>
</ul>
<div class="node">
<p><hr>
<a name="Encryption-algorithms-used-in-the-record-layer"></a>
Next: <a rel="next" accesskey="n" href="#Compression-algorithms-used-in-the-record-layer">Compression algorithms used in the record layer</a>,
Up: <a rel="up" accesskey="u" href="#The-TLS-record-protocol">The TLS record protocol</a>
</div>
<h4 class="subsection">3.3.1 Encryption algorithms used in the record layer</h4>
<p><a name="index-Symmetric-encryption-algorithms-5"></a>
Confidentiality in the record layer is achieved by using symmetric
block encryption algorithms like <code>3DES</code>, <code>AES</code><a rel="footnote" href="#fn-8" name="fnd-8"><sup>8</sup></a>, or stream algorithms like
<code>ARCFOUR_128</code><a rel="footnote" href="#fn-9" name="fnd-9"><sup>9</sup></a>. Ciphers are encryption algorithms that use a single, secret,
key to encrypt and decrypt data. Block algorithms in TLS also provide
protection against statistical analysis of the data. Thus, if you're
using the <acronym>TLS</acronym> protocol, a random number of blocks will be
appended to data, to prevent eavesdroppers from guessing the actual
data size.
<p>Supported cipher algorithms:
<dl>
<dt><code>3DES_CBC</code><dd><code>3DES_CBC</code> is the DES block cipher algorithm used with triple
encryption (EDE). Has 64 bits block size and is used in CBC mode.
<br><dt><code>ARCFOUR_128</code><dd>ARCFOUR is a fast stream cipher.
<br><dt><code>ARCFOUR_40</code><dd>This is the ARCFOUR cipher that is fed with a 40 bit key,
which is considered weak.
<br><dt><code>AES_CBC</code><dd>AES or RIJNDAEL is the block cipher algorithm that replaces the old
DES algorithm. Has 128 bits block size and is used in CBC mode. This
is not officially supported in TLS.
</dl>
<p>Supported MAC algorithms:
<dl>
<dt><code>MAC_MD5</code><dd>MD5 is a cryptographic hash algorithm designed by Ron Rivest. Outputs
128 bits of data.
<br><dt><code>MAC_SHA</code><dd>SHA is a cryptographic hash algorithm designed by NSA. Outputs 160
bits of data.
</dl>
<div class="node">
<p><hr>
<a name="Compression-algorithms-used-in-the-record-layer"></a>
Next: <a rel="next" accesskey="n" href="#Weaknesses-and-countermeasures">Weaknesses and countermeasures</a>,
Previous: <a rel="previous" accesskey="p" href="#Encryption-algorithms-used-in-the-record-layer">Encryption algorithms used in the record layer</a>,
Up: <a rel="up" accesskey="u" href="#The-TLS-record-protocol">The TLS record protocol</a>
</div>
<h4 class="subsection">3.3.2 Compression algorithms used in the record layer</h4>
<p><a name="index-Compression-algorithms-6"></a>
The TLS record layer also supports compression. The algorithms
implemented in <acronym>GnuTLS</acronym> can be found in the table below.
All the algorithms except for DEFLATE which is
referenced in <!-- %**else if -->
[RFC3749] (See <a href="#Bibliography">RFC3749</a>.)
, should be considered as
<acronym>GnuTLS</acronym>' extensions<a rel="footnote" href="#fn-10" name="fnd-10"><sup>10</sup></a>, and should be advertised only when the peer is known to
have a compliant client, to avoid interoperability problems.
<p>The included algorithms perform really good when text, or other
compressible data are to be transfered, but offer nothing on already
compressed data, such as compressed images, zipped archives etc.
These compression algorithms, may be useful in high bandwidth TLS
tunnels, and in cases where network usage has to be minimized. As a
drawback, compression increases latency.
<p>The record layer compression in <acronym>GnuTLS</acronym> is implemented based
on the proposal <!-- %**else if -->
[RFC3749] (See <a href="#Bibliography">RFC3749</a>.)
.
The supported compression algorithms are:
<dl>
<dt><code>DEFLATE</code><dd>Zlib compression, using the deflate algorithm.
<br><dt><code>LZO</code><dd>LZO is a very fast compression algorithm. This algorithm is only
available if the <acronym>GnuTLS-extra</acronym> library has been initialized
and the private extensions are enabled.
</dl>
<div class="node">
<p><hr>
<a name="Weaknesses-and-countermeasures"></a>
Previous: <a rel="previous" accesskey="p" href="#Compression-algorithms-used-in-the-record-layer">Compression algorithms used in the record layer</a>,
Up: <a rel="up" accesskey="u" href="#The-TLS-record-protocol">The TLS record protocol</a>
</div>
<h4 class="subsection">3.3.3 Weaknesses and countermeasures</h4>
<p>Some weaknesses that may affect the security of the Record layer have
been found in <acronym>TLS</acronym> 1.0 protocol. These weaknesses can be
exploited by active attackers, and exploit the facts that
<ol type=1 start=1>
<li><acronym>TLS</acronym> has separate alerts for “decryption_failed” and
“bad_record_mac”
<li>The decryption failure reason can be detected by timing the response
time.
<li>The IV for CBC encrypted packets is the last block of the previous
encrypted packet.
</ol>
<p>Those weaknesses were solved in <acronym>TLS</acronym> 1.1 <!-- %**else if -->
[RFC4346] (See <a href="#Bibliography">RFC4346</a>.)
which is implemented
in <acronym>GnuTLS</acronym>. For a detailed discussion see the archives of the
TLS Working Group mailing list and the paper <!-- %**else if -->
[CBCATT] (See <a href="#Bibliography">CBCATT</a>.)
.
<div class="node">
<p><hr>
<a name="The-TLS-Alert-Protocol"></a>
Next: <a rel="next" accesskey="n" href="#The-TLS-Handshake-Protocol">The TLS Handshake Protocol</a>,
Previous: <a rel="previous" accesskey="p" href="#The-TLS-record-protocol">The TLS record protocol</a>,
Up: <a rel="up" accesskey="u" href="#Introduction-to-TLS">Introduction to TLS</a>
</div>
<h3 class="section">3.4 The TLS Alert Protocol</h3>
<p><a name="The-Alert-Protocol"></a>
<a name="index-Alert-protocol-7"></a>
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
(see <code>GNUTLS_A_CLOSE_NOTIFY</code>), and others refer to the
application protocol solely (see <code>GNUTLS_A_USER_CANCELLED</code>). An
alert signal includes a level indication which may be either fatal or
warning. Fatal alerts always terminate the current connection, and
prevent future renegotiations using the current session ID.
<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.
<dl>
<dt><a href="#gnutls_005falert_005fsend">gnutls_alert_send</a>:<dd>To send an alert signal.
<br><dt><a href="#gnutls_005ferror_005fto_005falert">gnutls_error_to_alert</a>:<dd>To map a gnutls error number to an alert signal.
<br><dt><a href="#gnutls_005falert_005fget">gnutls_alert_get</a>:<dd>Returns the last received alert.
<br><dt><a href="#gnutls_005falert_005fget_005fname">gnutls_alert_get_name</a>:<dd>Returns the name, in a character array, of the given alert.
</dl>
<div class="node">
<p><hr>
<a name="The-TLS-Handshake-Protocol"></a>
Next: <a rel="next" accesskey="n" href="#TLS-Extensions">TLS Extensions</a>,
Previous: <a rel="previous" accesskey="p" href="#The-TLS-Alert-Protocol">The TLS Alert Protocol</a>,
Up: <a rel="up" accesskey="u" href="#Introduction-to-TLS">Introduction to TLS</a>
</div>
<h3 class="section">3.5 The TLS Handshake Protocol</h3>
<p><a name="The-Handshake-Protocol"></a>
<a name="index-Handshake-protocol-8"></a>
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. Available functions to control
the handshake protocol include:
<dl>
<dt><a href="#gnutls_005fcipher_005fset_005fpriority">gnutls_cipher_set_priority</a>:<dd>To set the priority of bulk cipher algorithms.
<br><dt><a href="#gnutls_005fmac_005fset_005fpriority">gnutls_mac_set_priority</a>:<dd>To set the priority of MAC algorithms.
<br><dt><a href="#gnutls_005fkx_005fset_005fpriority">gnutls_kx_set_priority</a>:<dd>To set the priority of key exchange algorithms.
<br><dt><a href="#gnutls_005fcompression_005fset_005fpriority">gnutls_compression_set_priority</a>:<dd>To set the priority of compression methods.
<br><dt><a href="#gnutls_005fcertificate_005ftype_005fset_005fpriority">gnutls_certificate_type_set_priority</a>:<dd>To set the priority of certificate types (e.g., <acronym>OpenPGP</acronym>,
<acronym>X.509</acronym>).
<br><dt><a href="#gnutls_005fprotocol_005fset_005fpriority">gnutls_protocol_set_priority</a>:<dd>To set the priority of protocol versions (e.g., <acronym>SSL</acronym> 3.0,
<acronym>TLS</acronym> 1.0).
<br><dt><a href="#gnutls_005fset_005fdefault_005fpriority">gnutls_set_default_priority</a>:<dd>To set some defaults in the current session. That way you don't have
to call each priority function, independently, but you have to live
with the defaults.
<br><dt><a href="#gnutls_005fcredentials_005fset">gnutls_credentials_set</a>:<dd>To set the appropriate credentials structures.
<br><dt><a href="#gnutls_005fcertificate_005fserver_005fset_005frequest">gnutls_certificate_server_set_request</a>:<dd>To set whether client certificate is required or not.
<br><dt><a href="#gnutls_005fhandshake">gnutls_handshake</a>:<dd>To initiate the handshake.
</dl>
<h4 class="subsection">3.5.1 TLS cipher suites</h4>
<p>The Handshake Protocol of <acronym>TLS</acronym> negotiates cipher suites of
the form <code>TLS_DHE_RSA_WITH_3DES_CBC_SHA</code>. The usual cipher
suites contain these parameters:
<ul>
<li>The key exchange algorithm.
<code>DHE_RSA</code> in the example.
<li>The Symmetric encryption algorithm and mode
<code>3DES_CBC</code> in this example.
<li>The MAC<a rel="footnote" href="#fn-11" name="fnd-11"><sup>11</sup></a> algorithm used for authentication.
<code>MAC_SHA</code> is used in the above example.
</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 <acronym>TLS</acronym> to negotiate the
strongest available cipher suite. Do not enable ciphers and algorithms
that you consider weak.
<p>The priority functions, dicussed above, allow the application layer to
enable and set priorities on the individual ciphers. It may imply that
all combinations of ciphersuites are allowed, but this is not
true. For several reasons, not discussed here, some combinations were
not defined in the <acronym>TLS</acronym> protocol. The supported ciphersuites
are shown in <a href="#ciphersuites">ciphersuites</a>.
<h4 class="subsection">3.5.2 Client authentication</h4>
<p><a name="index-Client-Certificate-authentication-9"></a>
In the case of ciphersuites that use certificate authentication, the
authentication of the client is optional in <acronym>TLS</acronym>. A server
may request a certificate from the client — using the
<a href="#gnutls_005fcertificate_005fserver_005fset_005frequest">gnutls_certificate_server_set_request</a> function. If a
certificate is to be requested from the client during the handshake,
the server will send a certificate request message that contains a
list of acceptable certificate signers. In <acronym>GnuTLS</acronym> the certificate
signers list is constructed using the trusted Certificate Authorities by the
server. That is the ones set using
<ul>
<li><a href="#gnutls_005fcertificate_005fset_005fx509_005ftrust_005ffile">gnutls_certificate_set_x509_trust_file</a>
<li><a href="#gnutls_005fcertificate_005fset_005fx509_005ftrust_005fmem">gnutls_certificate_set_x509_trust_mem</a>
</ul>
<p>Sending of the names of the CAs can be controlled using
<a href="#gnutls_005fcertificate_005fsend_005fx509_005frdn_005fsequence">gnutls_certificate_send_x509_rdn_sequence</a>. The client, then,
may send a certificate, signed by one of the server's acceptable
signers.
<h4 class="subsection">3.5.3 Resuming Sessions</h4>
<p><a name="resume"></a>
<a name="index-Resuming-sessions-10"></a>
The <a href="#gnutls_005fhandshake">gnutls_handshake</a> function, is expensive since a lot of
calculations are performed. In order to support many fast connections
to the same server a client may use session resuming. <strong>Session
resuming</strong> is a feature of the <acronym>TLS</acronym> protocol which allows a
client to connect to a server, after a successful handshake, without
the expensive calculations. This is achieved by using the previously
established keys. <acronym>GnuTLS</acronym> supports this feature, and the
example (see <a href="#ex_003aresume_002dclient">ex:resume-client</a>) illustrates a typical use of it.
<p>Keep in mind that sessions are expired after some time, for security
reasons, thus it may be normal for a server not to resume a session
even if you requested that. Also note that you must enable, using the
priority functions, at least the algorithms used in the last session.
<h4 class="subsection">3.5.4 Resuming internals</h4>
<p>The resuming capability, mostly in the server side, is one of the
problems of a thread-safe TLS implementations. The problem is that all
threads must share information in order to be able to resume
sessions. The gnutls approach is, in case of a client, to leave all
the burden of resuming to the client. I.e., copy and keep the necessary
parameters. See the functions:
<ul>
<li><a href="#gnutls_005fsession_005fget_005fdata">gnutls_session_get_data</a>
<li><a href="#gnutls_005fsession_005fget_005fid">gnutls_session_get_id</a>
<li><a href="#gnutls_005fsession_005fset_005fdata">gnutls_session_set_data</a>
</ul>
<p>The server side is different. A server has to specify some callback
functions which store, retrieve and delete session data. These can be
registered with:
<ul>
<li><a href="#gnutls_005fdb_005fset_005fremove_005ffunction">gnutls_db_set_remove_function</a>
<li><a href="#gnutls_005fdb_005fset_005fstore_005ffunction">gnutls_db_set_store_function</a>
<li><a href="#gnutls_005fdb_005fset_005fretrieve_005ffunction">gnutls_db_set_retrieve_function</a>
<li><a href="#gnutls_005fdb_005fset_005fptr">gnutls_db_set_ptr</a>
</ul>
<p>It might also be useful to be able to check for expired sessions in
order to remove them, and save space. The function
<a href="#gnutls_005fdb_005fcheck_005fentry">gnutls_db_check_entry</a> is provided for that reason.
<div class="node">
<p><hr>
<a name="TLS-Extensions"></a>
Next: <a rel="next" accesskey="n" href="#On-SSL-2-and-older-protocols">On SSL 2 and older protocols</a>,
Previous: <a rel="previous" accesskey="p" href="#The-TLS-Handshake-Protocol">The TLS Handshake Protocol</a>,
Up: <a rel="up" accesskey="u" href="#Introduction-to-TLS">Introduction to TLS</a>
</div>
<h3 class="section">3.6 TLS Extensions</h3>
<p><a name="index-TLS-Extensions-11"></a>
A number of extensions to the <acronym>TLS</acronym> protocol have been
proposed mainly in <!-- %**else if -->
[TLSEXT] (See <a href="#Bibliography">TLSEXT</a>.)
. The extensions supported
in <acronym>GnuTLS</acronym> are:
<ul>
<li>Maximum fragment length negotiation
<li>Server name indication
</ul>
<p>and they will be discussed in the subsections that follow.
<h4 class="subsection">3.6.1 Maximum fragment length negotiation</h4>
<p><a name="index-TLS-Extensions-12"></a><a name="index-Maximum-fragment-length-13"></a>
This extension allows a <acronym>TLS</acronym> implementation to negotiate a
smaller value for record packet maximum length. This extension may be
useful to clients with constrained capabilities. See the
<a href="#gnutls_005frecord_005fset_005fmax_005fsize">gnutls_record_set_max_size</a> and the
<a href="#gnutls_005frecord_005fget_005fmax_005fsize">gnutls_record_get_max_size</a> functions.
<h4 class="subsection">3.6.2 Server name indication</h4>
<p><a name="serverind"></a>
<a name="index-TLS-Extensions-14"></a><a name="index-Server-name-indication-15"></a>
A common problem in <acronym>HTTPS</acronym> servers is the fact that the
<acronym>TLS</acronym> protocol is not aware of the hostname that a client
connects to, when the handshake procedure begins. For that reason the
<acronym>TLS</acronym> server has no way to know which certificate to send.
<p>This extension solves that problem within the <acronym>TLS</acronym> protocol,
and allows a client to send the HTTP hostname before the handshake
begins within the first handshake packet. The functions
<a href="#gnutls_005fserver_005fname_005fset">gnutls_server_name_set</a> and <a 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.
<div class="node">
<p><hr>
<a name="On-SSL-2-and-older-protocols"></a>
Previous: <a rel="previous" accesskey="p" href="#TLS-Extensions">TLS Extensions</a>,
Up: <a rel="up" accesskey="u" href="#Introduction-to-TLS">Introduction to TLS</a>
</div>
<h3 class="section">3.7 On SSL 2 and older protocols</h3>
<p><a name="index-SSL-2-16"></a>
One of the initial decisions in the <acronym>GnuTLS</acronym> development was
to implement the known security protocols for the transport layer.
Initially <acronym>TLS</acronym> 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 <acronym>SSL</acronym> 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>One question that may arise is why we didn't implement <acronym>SSL</acronym>
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.
<p><a name="index-PCT-17"></a>Other protocols such as Microsoft's <acronym>PCT</acronym> 1 and <acronym>PCT</acronym>
2 were not implemented because they were also abandoned and deprecated
by <acronym>SSL</acronym> 3.0 and later <acronym>TLS</acronym> 1.0.
<div class="node">
<p><hr>
<a name="Authentication-methods"></a>
Next: <a rel="next" accesskey="n" href="#More-on-certificate-authentication">More on certificate authentication</a>,
Previous: <a rel="previous" accesskey="p" href="#Introduction-to-TLS">Introduction to TLS</a>,
Up: <a rel="up" accesskey="u" href="#Top">Top</a>
</div>
<h2 class="chapter">4 Authentication methods</h2>
<p>The <acronym>TLS</acronym> protocol provides confidentiality and encryption,
but also offers authentication, which is a prerequisite for a secure
connection. The available authentication methods in <acronym>GnuTLS</acronym>
are:
<ul>
<li>Certificate authentication
<li>Anonymous authentication
<li><acronym>SRP</acronym> authentication
<li><acronym>PSK</acronym> authentication
</ul>
<ul class="menu">
<li><a accesskey="1" href="#Certificate-authentication">Certificate authentication</a>
<li><a accesskey="2" href="#Anonymous-authentication">Anonymous authentication</a>
<li><a accesskey="3" href="#Authentication-using-SRP">Authentication using SRP</a>
<li><a accesskey="4" href="#Authentication-using-PSK">Authentication using PSK</a>
<li><a accesskey="5" href="#Authentication-and-credentials">Authentication and credentials</a>
<li><a accesskey="6" href="#Parameters-stored-in-credentials">Parameters stored in credentials</a>
</ul>
<div class="node">
<p><hr>
<a name="Certificate-authentication"></a>
Next: <a rel="next" accesskey="n" href="#Anonymous-authentication">Anonymous authentication</a>,
Up: <a rel="up" accesskey="u" href="#Authentication-methods">Authentication methods</a>
</div>
<h3 class="section">4.1 Certificate authentication</h3>
<h4 class="subsection">4.1.1 Authentication using <acronym>X.509</acronym> certificates</h4>
<p><a name="index-g_t_0040acronym_007bX_002e509_007d-certificates-18"></a>
<acronym>X.509</acronym> certificates contain the public parameters, of a
public key algorithm, and an authority's signature, which proves the
authenticity of the parameters. See <a href="#The-X_002e509-trust-model">The X.509 trust model</a>, for
more information on <acronym>X.509</acronym> protocols.
<h4 class="subsection">4.1.2 Authentication using <acronym>OpenPGP</acronym> keys</h4>
<p><a name="index-g_t_0040acronym_007bOpenPGP_007d-Keys-19"></a>
<acronym>OpenPGP</acronym> keys also contain public parameters of a public key
algorithm, and signatures from several other parties. Depending on
whether a signer is trusted the key is considered trusted or not.
<acronym>GnuTLS</acronym>'s <acronym>OpenPGP</acronym> authentication implementation is
based on the <!-- %**else if -->
[TLSPGP] (See <a href="#Bibliography">TLSPGP</a>.)
proposal.
<p>See <a href="#The-OpenPGP-trust-model">The OpenPGP trust model</a>, for more information about the
<acronym>OpenPGP</acronym> trust model. For a more detailed introduction to
<acronym>OpenPGP</acronym> and <acronym>GnuPG</acronym> see <!-- %**else if -->
[GPGH] (See <a href="#Bibliography">GPGH</a>.)
.
<h4 class="subsection">4.1.3 Using certificate authentication</h4>
<p>In <acronym>GnuTLS</acronym> both the <acronym>OpenPGP</acronym> and <acronym>X.509</acronym>
certificates are part of the certificate authentication and thus are
handled using a common API.
<p>When using certificates the server is required to have at least one
certificate and private key pair. A client may or may not have such a
pair. The certificate and key pair should be loaded, before any
<acronym>TLS</acronym> session is initialized, in a certificate credentials
structure. This should be done by using
<a href="#gnutls_005fcertificate_005fset_005fx509_005fkey_005ffile">gnutls_certificate_set_x509_key_file</a> or
<a href="#gnutls_005fcertificate_005fset_005fopenpgp_005fkey_005ffile">gnutls_certificate_set_openpgp_key_file</a> depending on the
certificate type. In the <acronym>X.509</acronym> case, the functions will
also accept and use a certificate list that leads to a trusted
authority. The certificate list must be ordered in such way that every
certificate certifies the one before it. The trusted authority's
certificate need not to be included, since the peer should possess it
already.
<p>As an alternative, a callback may be used so the server or the client
specify the certificate and the key at the handshake time. That
callback can be set using the functions:
<ul>
<li><a href="#gnutls_005fcertificate_005fserver_005fset_005fretrieve_005ffunction">gnutls_certificate_server_set_retrieve_function</a>
<li><a href="#gnutls_005fcertificate_005fclient_005fset_005fretrieve_005ffunction">gnutls_certificate_client_set_retrieve_function</a>
</ul>
<p>Certificate verification is possible by loading the trusted
authorities into the credentials structure by using
<a href="#gnutls_005fcertificate_005fset_005fx509_005ftrust_005ffile">gnutls_certificate_set_x509_trust_file</a> or
<a href="#gnutls_005fcertificate_005fset_005fopenpgp_005fkeyring_005ffile">gnutls_certificate_set_openpgp_keyring_file</a> for openpgp
keys. Note however that the peer's certificate is not automatically
verified, you should call <a href="#gnutls_005fcertificate_005fverify_005fpeers2">gnutls_certificate_verify_peers2</a>,
after a successful handshake, to verify the signatures of the
certificate. An alternative way, which reports a more detailed
verification output, is to use <a 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 href="#The-X_002e509-trust-model">The X.509 trust model</a>.
<p>In a handshake, the negotiated cipher suite depends on the
certificate's parameters, so not all key exchange methods will be
available with some certificates. <acronym>GnuTLS</acronym> 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, but only the
<code>DHE_RSA</code> ones. It is recommended not to use RSA keys for both
signing and encryption. If possible use the same key for the
<code>DHE_RSA</code> and <code>RSA_EXPORT</code> ciphersuites, which use signing,
and a different key for the plain RSA ciphersuites, which use
encryption. All the key exchange methods shown below are available in
certificate authentication.
<p>Note that the DHE key exchange methods are generally
slower<a rel="footnote" href="#fn-12" name="fnd-12"><sup>12</sup></a> than plain RSA and require Diffie
Hellman parameters to be generated and associated with a credentials
structure, by the server. The <code>RSA-EXPORT</code> method also requires 512 bit RSA
parameters, that should also be generated and associated with the
credentials structure. See the functions:
<ul>
<li><a href="#gnutls_005fdh_005fparams_005fgenerate2">gnutls_dh_params_generate2</a>
<li><a href="#gnutls_005fcertificate_005fset_005fdh_005fparams">gnutls_certificate_set_dh_params</a>
<li><a href="#gnutls_005frsa_005fparams_005fgenerate2">gnutls_rsa_params_generate2</a>
<li><a href="#gnutls_005fcertificate_005fset_005frsa_005fexport_005fparams">gnutls_certificate_set_rsa_export_params</a>
</ul>
<p>Sometimes in order to avoid bottlenecks in programs it is usefull to store
and read parameters from formats that can be generated by external programs such
as <code>certtool</code>. This is possible with <acronym>GnuTLS</acronym> by using the following
functions:
<ul>
<li><a href="#gnutls_005fdh_005fparams_005fimport_005fpkcs3">gnutls_dh_params_import_pkcs3</a>
<li><a href="#gnutls_005frsa_005fparams_005fimport_005fpkcs1">gnutls_rsa_params_import_pkcs1</a>
<li><a href="#gnutls_005fdh_005fparams_005fexport_005fpkcs3">gnutls_dh_params_export_pkcs3</a>
<li><a href="#gnutls_005frsa_005fparams_005fexport_005fpkcs1">gnutls_rsa_params_export_pkcs1</a>
</ul>
<p>Key exchange algorithms for <acronym>OpenPGP</acronym> and <acronym>X.509</acronym>
certificates:
<dl>
<dt><code>RSA:</code><dd>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.
<br><dt><code>RSA_EXPORT:</code><dd>The RSA algorithm is used to encrypt a key and send it to the peer.
In the EXPORT algorithm, the server signs temporary RSA parameters of
512 bits — which are considered weak — and sends them to the client.
<br><dt><code>DHE_RSA:</code><dd>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.
<br><dt><code>DHE_DSS:</code><dd>The DSS 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. DSS stands for Digital
Signature Standard.
</dl>
<div class="node">
<p><hr>
<a name="Anonymous-authentication"></a>
Next: <a rel="next" accesskey="n" href="#Authentication-using-SRP">Authentication using SRP</a>,
Previous: <a rel="previous" accesskey="p" href="#Certificate-authentication">Certificate authentication</a>,
Up: <a rel="up" accesskey="u" href="#Authentication-methods">Authentication methods</a>
</div>
<h3 class="section">4.2 Anonymous authentication</h3>
<p><a name="index-Anonymous-authentication-20"></a>
The anonymous key exchange performs encryption but there is no
indication of the identity of the peer. This kind of authentication
is vulnerable to a man in the middle attack, but this protocol can be
used even if there is no prior communication and trusted parties with
the peer, or when full anonymity is required. Unless really required,
do not use anonymous authentication. Available key exchange methods
are shown below.
<p>Note that the key exchange methods for anonymous authentication
require Diffie Hellman parameters to be generated by the server and associated with
an anonymous credentials structure.
<p>Supported anonymous key exchange algorithms:
<dl>
<dt><code>ANON_DH:</code><dd>This algorithm exchanges Diffie Hellman parameters.
</dl>
<div class="node">
<p><hr>
<a name="Authentication-using-SRP"></a>
Next: <a rel="next" accesskey="n" href="#Authentication-using-PSK">Authentication using PSK</a>,
Previous: <a rel="previous" accesskey="p" href="#Anonymous-authentication">Anonymous authentication</a>,
Up: <a rel="up" accesskey="u" href="#Authentication-methods">Authentication methods</a>
</div>
<h3 class="section">4.3 Authentication using <acronym>SRP</acronym></h3>
<p><a name="index-g_t_0040acronym_007bSRP_007d-authentication-21"></a>
Authentication via the Secure Remote Password protocol,
<acronym>SRP</acronym><a rel="footnote" href="#fn-13" name="fnd-13"><sup>13</sup></a>,
is supported. The <acronym>SRP</acronym> key exchange is an extension to the
<acronym>TLS</acronym> protocol, and it is a password based authentication
(unlike <acronym>X.509</acronym> or <acronym>OpenPGP</acronym> that use certificates).
The two peers can be identified using a single password, or there can
be combinations where the client is authenticated using <acronym>SRP</acronym>
and the server using a certificate.
<p>The advantage of <acronym>SRP</acronym> authentication, over other proposed
secure password authentication schemes, is that <acronym>SRP</acronym> does not
require the server to hold the user's password. This kind of
protection is similar to the one used traditionally in the <em>UNIX</em>
<samp><span class="file">/etc/passwd</span></samp> file, where the contents of this file did not cause
harm to the system security if they were revealed. The <acronym>SRP</acronym>
needs instead of the plain password something called a verifier, which
is calculated using the user's password, and if stolen cannot be used
to impersonate the user. Check <!-- %**else if -->
[TOMSRP] (See <a href="#Bibliography">TOMSRP</a>.)
for a detailed description
of the <acronym>SRP</acronym> protocol and the Stanford <acronym>SRP</acronym>
libraries, which includes a PAM module that synchronizes the system's
users passwords with the <acronym>SRP</acronym> password files. That way
<acronym>SRP</acronym> authentication could be used for all the system's users.
<p>The implementation in <acronym>GnuTLS</acronym> is based on paper
<!-- %**else if -->
[TLSSRP] (See <a href="#Bibliography">TLSSRP</a>.)
. The supported <acronym>SRP</acronym> key exchange methods are:
<dl>
<dt><code>SRP:</code><dd>Authentication using the <acronym>SRP</acronym> protocol.
<br><dt><code>SRP_DSS:</code><dd>Client authentication using the <acronym>SRP</acronym> protocol. Server is
authenticated using a certificate with DSA parameters.
<br><dt><code>SRP_RSA:</code><dd>Client authentication using the <acronym>SRP</acronym> protocol. Server is
authenticated using a certificate with RSA parameters.
</dl>
<p>If clients supporting <acronym>SRP</acronym> know the username and password
before the connection, should initialize the client credentials and
call the function <a href="#gnutls_005fsrp_005fset_005fclient_005fcredentials">gnutls_srp_set_client_credentials</a>.
Alternatively they could specify a callback function by using the
function <a href="#gnutls_005fsrp_005fset_005fclient_005fcredentials_005ffunction">gnutls_srp_set_client_credentials_function</a>. This has
the advantage that allows probing the server for <acronym>SRP</acronym>
support. In that case the callback function will be called twice per
handshake. The first time is before the ciphersuite is negotiated,
and if the callback returns a negative error code, the callback will
be called again if <acronym>SRP</acronym> has been negotiated. This uses a
special <acronym>TLS</acronym>-<acronym>SRP</acronym> handshake idiom in order to avoid,
in interactive applications, to ask the user for <acronym>SRP</acronym>
password and username if the server does not negotiate an
<acronym>SRP</acronym> ciphersuite.
<p>In server side the default behaviour of <acronym>GnuTLS</acronym> is to read
the usernames and <acronym>SRP</acronym> verifiers from password files. These
password files are the ones used by the <em>Stanford srp libraries</em>
and can be specified using the
<a href="#gnutls_005fsrp_005fset_005fserver_005fcredentials_005ffile">gnutls_srp_set_server_credentials_file</a>. If a different
password file format is to be used, then the function
<a href="#gnutls_005fsrp_005fset_005fserver_005fcredentials_005ffunction">gnutls_srp_set_server_credentials_function</a>, should be called,
in order to set an appropriate callback.
<p>Some helper functions such as
<ul>
<li><a href="#gnutls_005fsrp_005fverifier">gnutls_srp_verifier</a>
<li><a href="#gnutls_005fsrp_005fbase64_005fencode">gnutls_srp_base64_encode</a>
<li><a href="#gnutls_005fsrp_005fbase64_005fdecode">gnutls_srp_base64_decode</a>
</ul>
<p>are included in <acronym>GnuTLS</acronym>, and can be used to generate and
maintain <acronym>SRP</acronym> verifiers and password files. A program to
manipulate the required parameters for <acronym>SRP</acronym> authentication is
also included. See <a href="#srptool">srptool</a>, for more information.
<div class="node">
<p><hr>
<a name="Authentication-using-PSK"></a>
Next: <a rel="next" accesskey="n" href="#Authentication-and-credentials">Authentication and credentials</a>,
Previous: <a rel="previous" accesskey="p" href="#Authentication-using-SRP">Authentication using SRP</a>,
Up: <a rel="up" accesskey="u" href="#Authentication-methods">Authentication methods</a>
</div>
<h3 class="section">4.4 Authentication using <acronym>PSK</acronym></h3>
<p><a name="index-g_t_0040acronym_007bPSK_007d-authentication-22"></a>
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.
<p>The implementation in <acronym>GnuTLS</acronym> is based on paper
<!-- %**else if -->
[TLSPSK] (See <a href="#Bibliography">TLSPSK</a>.)
. The supported <acronym>PSK</acronym> key exchange methods are:
<dl>
<dt><code>PSK:</code><dd>Authentication using the <acronym>PSK</acronym> protocol.
<br><dt><code>DHE-PSK:</code><dd>Authentication using the <acronym>PSK</acronym> protocol and Diffie Hellman key exchange.
This method offers perfect forward secrecy.
</dl>
<p>Clients supporting <acronym>PSK</acronym> should supply the username and key
before the connection to the client credentials by calling
the function <a href="#gnutls_005fpsk_005fset_005fclient_005fcredentials">gnutls_psk_set_client_credentials</a>.
Alternatively they could specify a callback function by using the
function <a href="#gnutls_005fpsk_005fset_005fclient_005fcredentials_005ffunction">gnutls_psk_set_client_credentials_function</a>.
This has the advantage that the callback will be called only if <acronym>PSK</acronym>
has been negotiated.
<p>In server side the default behaviour of <acronym>GnuTLS</acronym> is to read
the usernames and <acronym>PSK</acronym> 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 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 the function
<a href="#gnutls_005fpsk_005fset_005fserver_005fcredentials_005ffunction">gnutls_psk_set_server_credentials_function</a>, should be used instead.
<p>Some helper functions such as:
<ul>
<li><a href="#gnutls_005fhex_005fencode">gnutls_hex_encode</a>
<li><a href="#gnutls_005fhex_005fdecode">gnutls_hex_decode</a>
</ul>
<p>are included in <acronym>GnuTLS</acronym>, and may be used to generate and
maintain <acronym>PSK</acronym> keys.
<div class="node">
<p><hr>
<a name="Authentication-and-credentials"></a>
Next: <a rel="next" accesskey="n" href="#Parameters-stored-in-credentials">Parameters stored in credentials</a>,
Previous: <a rel="previous" accesskey="p" href="#Authentication-using-PSK">Authentication using PSK</a>,
Up: <a rel="up" accesskey="u" href="#Authentication-methods">Authentication methods</a>
</div>
<h3 class="section">4.5 Authentication and credentials</h3>
<p>In <acronym>GnuTLS</acronym> every key exchange method is associated with a
credentials type. So in order to enable to enable a specific method,
the corresponding credentials type should be initialized and set using
<a href="#gnutls_005fcredentials_005fset">gnutls_credentials_set</a>. A mapping is shown below.
<p>Key exchange algorithms and the corresponding credential types:
<p><table summary="">
<tr align="left"><th valign="top" width="30%">Key exchange </th><th valign="top" width="30%">Client credentials </th><th valign="top" width="30%">Server credentials
<p><br></th></tr><tr align="left"><td valign="top" width="30%"><code>KX_RSA</code>
<br></td></tr><tr align="left"><td valign="top" width="30%"><code>KX_DHE_RSA</code>
<br></td></tr><tr align="left"><td valign="top" width="30%"><code>KX_DHE_DSS</code>
<br></td></tr><tr align="left"><td valign="top" width="30%"><code>KX_RSA_EXPORT</code>
</td><td valign="top" width="30%"><code>CRD_CERTIFICATE</code>
</td><td valign="top" width="30%"><code>CRD_CERTIFICATE</code>
<p><br></td></tr><tr align="left"><td valign="top" width="30%"><code>KX_SRP_RSA</code>
</td><td valign="top" width="30%"><code>CRD_SRP</code>
</td><td valign="top" width="30%"><code>CRD_SRP</code>
<br></td></tr><tr align="left"><td valign="top" width="30%"><code>KX_SRP_DSS</code>
</td><td valign="top" width="30%">
</td><td valign="top" width="30%"><code>CRD_CERTIFICATE</code>
<p><br></td></tr><tr align="left"><td valign="top" width="30%"><code>KX_SRP</code>
</td><td valign="top" width="30%"><code>CRD_SRP</code>
</td><td valign="top" width="30%"><code>CRD_SRP</code>
<p><br></td></tr><tr align="left"><td valign="top" width="30%"><code>KX_ANON_DH</code>
</td><td valign="top" width="30%"><code>CRD_ANON</code>
</td><td valign="top" width="30%"><code>CRD_ANON</code>
<p><br></td></tr><tr align="left"><td valign="top" width="30%"><code>KX_PSK</code>
</td><td valign="top" width="30%"><code>CRD_PSK</code>
</td><td valign="top" width="30%"><code>CRD_PSK</code>
<br></td></tr></table>
<div class="node">
<p><hr>
<a name="Parameters-stored-in-credentials"></a>
Previous: <a rel="previous" accesskey="p" href="#Authentication-and-credentials">Authentication and credentials</a>,
Up: <a rel="up" accesskey="u" href="#Authentication-methods">Authentication methods</a>
</div>
<h3 class="section">4.6 Parameters stored in credentials</h3>
<p>Several parameters such as the ones used for Diffie-Hellman
authentication are stored within the credentials structures, so all
sessions can access them. Those parameters are stored in structures
such as <code>gnutls_dh_params_t</code> and <code>gnutls_rsa_params_t</code>, and
functions like <a href="#gnutls_005fcertificate_005fset_005fdh_005fparams">gnutls_certificate_set_dh_params</a> and
<a href="#gnutls_005fcertificate_005fset_005frsa_005fexport_005fparams">gnutls_certificate_set_rsa_export_params</a> can be used to
associate those parameters with the given credentials structure.
<p>Since those parameters need to be renewed from time to time and a
global structure such as the credentials, may not be easy to modify
since it is accessible by all sessions, an alternative interface is
available using a callback function. This can be set using the
<a href="#gnutls_005fcertificate_005fset_005fparams_005ffunction">gnutls_certificate_set_params_function</a>. An example is shown
below.
<pre class="example"> #include <gnutls.h>
gnutls_rsa_params_t rsa_params;
gnutls_dh_params_t dh_params;
/* This function will be called once a session requests DH
* or RSA parameters. The parameters returned (if any) will
* be used for the first handshake only.
*/
static int get_params( gnutls_session_t session,
gnutls_params_type_t type,
gnutls_params_st *st)
{
if (type == GNUTLS_PARAMS_RSA_EXPORT)
st->params.rsa_export = rsa_params;
else if (type == GNUTLS_PARAMS_DH)
st->params.dh = dh_params;
else return -1;
st->type = type;
/* do not deinitialize those parameters.
*/
st->deinit = 0;
return 0;
}
int main()
{
gnutls_certificate_credentials_t cert_cred;
initialize_params();
/* ...
*/
gnutls_certificate_set_params_function( cert_cred, get_params);
}
</pre>
<div class="node">
<p><hr>
<a name="More-on-certificate-authentication"></a>
Next: <a rel="next" accesskey="n" href="#How-to-use-TLS-in-application-protocols">How to use TLS in application protocols</a>,
Previous: <a rel="previous" accesskey="p" href="#Authentication-methods">Authentication methods</a>,
Up: <a rel="up" accesskey="u" href="#Top">Top</a>
</div>
<h2 class="chapter">5 More on certificate authentication</h2>
<p><a name="Certificate-Authentication"></a>
<a name="index-Certificate-authentication-23"></a>
<ul class="menu">
<li><a accesskey="1" href="#The-X_002e509-trust-model">The X.509 trust model</a>
<li><a accesskey="2" href="#The-OpenPGP-trust-model">The OpenPGP trust model</a>
<li><a accesskey="3" href="#Digital-signatures">Digital signatures</a>
</ul>
<div class="node">
<p><hr>
<a name="The-X.509-trust-model"></a>
<a name="The-X_002e509-trust-model"></a>
Next: <a rel="next" accesskey="n" href="#The-OpenPGP-trust-model">The OpenPGP trust model</a>,
Up: <a rel="up" accesskey="u" href="#More-on-certificate-authentication">More on certificate authentication</a>
</div>
<h3 class="section">5.1 The <acronym>X.509</acronym> trust model</h3>
<p><a name="index-g_t_0040acronym_007bX_002e509_007d-certificates-24"></a>
The <acronym>X.509</acronym> 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.
<div class="block-image"><img src="x509-1.png" alt="x509-1.png"></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. See the figure above for a typical example. The API for
handling <acronym>X.509</acronym> certificates is described at section
<a href="#sec_003ax509api">sec:x509api</a>. Some examples are listed below.
<ul class="menu">
<li><a accesskey="1" href="#X_002e509-certificates">X.509 certificates</a>
<li><a accesskey="2" href="#Verifying-X_002e509-certificate-paths">Verifying X.509 certificate paths</a>
<li><a accesskey="3" href="#PKCS-_002310-certificate-requests">PKCS #10 certificate requests</a>
<li><a accesskey="4" href="#PKCS-_002312-structures">PKCS #12 structures</a>
</ul>
<div class="node">
<p><hr>
<a name="X.509-certificates"></a>
<a name="X_002e509-certificates"></a>
Next: <a rel="next" accesskey="n" href="#Verifying-X_002e509-certificate-paths">Verifying X.509 certificate paths</a>,
Up: <a rel="up" accesskey="u" href="#The-X_002e509-trust-model">The X.509 trust model</a>
</div>
<h4 class="subsection">5.1.1 <acronym>X.509</acronym> certificates</h4>
<p>An <acronym>X.509</acronym> certificate usually contains information about the
certificate holder, the signer, a unique serial number, expiration
dates and some other fields <!-- %**else if -->
[RFC3280] (See <a href="#Bibliography">RFC3280</a>.)
as shown in the table
below.
<dl>
<dt><code>version:</code><dd>The field that indicates the version of the certificate.
<br><dt><code>serialNumber:</code><dd>This field holds a unique serial number per certificate.
<br><dt><code>issuer:</code><dd>Holds the issuer's distinguished name.
<br><dt><code>validity:</code><dd>The activation and expiration dates.
<br><dt><code>subject:</code><dd>The subject's distinguished name of the certificate.
<br><dt><code>extensions:</code><dd>The extensions are fields only present in version 3 certificates.
</dl>
<p>The certificate's <em>subject or issuer name</em> is not just a single
string. It is a Distinguished name and in the <acronym>ASN.1</acronym>
notation is a sequence of several object IDs with their corresponding
values. Some of available OIDs to be used in an <acronym>X.509</acronym>
distinguished name are defined in <samp><span class="file">gnutls/x509.h</span></samp>.
<p>The <em>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>The <em>validity</em> dates are there to indicate the date that the
specific certificate was activated and the date the certificate's key
would be considered invalid.
<p>Certificate <em>extensions</em> are there to include information about
the certificate's subject that did not fit in the typical certificate
fields. Those may be e-mail addresses, flags that indicate whether the
belongs to a CA etc. All the supported <acronym>X.509</acronym> version 3
extensions are shown in the table below.
<dl>
<dt><code>subject key id (2.5.29.14):</code><dd>An identifier of the key of the subject.
<br><dt><code>authority key id (2.5.29.35):</code><dd>An identifier of the authority's key used to sign the certificate.
<br><dt><code>subject alternative name (2.5.29.17):</code><dd>Alternative names to subject's distinguished name.
<br><dt><code>key usage (2.5.29.15):</code><dd>Constraints the key's usage of the certificate.
<br><dt><code>extended key usage (2.5.29.37):</code><dd>Constraints the purpose of the certificate.
<br><dt><code>basic constraints (2.5.29.19):</code><dd>Indicates whether this is a CA certificate or not.
<br><dt><code>CRL distribution points (2.5.29.31):</code><dd>This extension is set by the CA, in order to inform about the issued CRLs.
</dl>
<p>In <acronym>GnuTLS</acronym> the <acronym>X.509</acronym> certificate structures are handled using
the <code>gnutls_x509_crt_t</code> type and the corresponding private keys
with the <code>gnutls_x509_privkey_t</code> type. All the available
functions for <acronym>X.509</acronym> certificate handling have their prototypes in
<samp><span class="file">gnutls/x509.h</span></samp>. An example program to demonstrate the <acronym>X.509</acronym>
parsing capabilities can be found at section <a href="#ex_003ax509_002dinfo">ex:x509-info</a>.
<div class="node">
<p><hr>
<a name="Verifying-X.509-certificate-paths"></a>
<a name="Verifying-X_002e509-certificate-paths"></a>
Next: <a rel="next" accesskey="n" href="#PKCS-_002310-certificate-requests">PKCS #10 certificate requests</a>,
Previous: <a rel="previous" accesskey="p" href="#X_002e509-certificates">X.509 certificates</a>,
Up: <a rel="up" accesskey="u" href="#The-X_002e509-trust-model">The X.509 trust model</a>
</div>
<h4 class="subsection">5.1.2 Verifying <acronym>X.509</acronym> certificate paths</h4>
<p><a name="index-Verifying-certificate-paths-25"></a>
Verifying certificate paths is important in <acronym>X.509</acronym> authentication. For
this purpose the function <a href="#gnutls_005fx509_005fcrt_005fverify">gnutls_x509_crt_verify</a> is
provided. The output of this function is the bitwise OR of the
elements of the <code>gnutls_certificate_status_t</code> enumeration. A
detailed description of these elements can be found in figure below.
The function <a href="#gnutls_005fcertificate_005fverify_005fpeers2">gnutls_certificate_verify_peers2</a> is equivalent to
the previous one, and will verify the peer's certificate in a TLS
session.
<dl>
<dt><code>CERT_INVALID:</code><dd>The certificate is not signed by one of the known authorities, or
the signature is invalid.
<br><dt><code>CERT_REVOKED:</code><dd>The certificate has been revoked by its CA.
<br><dt><code>CERT_SIGNER_NOT_FOUND:</code><dd>The certificate's issuer is not known. This is the case when the
issuer is not in the trusted certificates list.
<br><dt><code>GNUTLS_CERT_SIGNER_NOT_CA:</code><dd>The certificate'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><a name="GNUTLS_005fCERT_005fINSECURE_005fALGORITHM"></a>
<br><dt><code>GNUTLS_CERT_INSECURE_ALGORITHM:</code><dd>The certificate was signed using an insecure algorithm such as MD2 or
MD5. These algorithms have been broken and should not be trusted.
</dl>
<p>There is also to possibility to pass some input to the verification
functions in the form of flags. For <a href="#gnutls_005fx509_005fcrt_005fverify">gnutls_x509_crt_verify</a> the
flags are passed straightforward, but
<a href="#gnutls_005fcertificate_005fverify_005fpeers2">gnutls_certificate_verify_peers2</a> depends on the flags set by
calling <a href="#gnutls_005fcertificate_005fset_005fverify_005fflags">gnutls_certificate_set_verify_flags</a>. All the available
flags are part of the enumeration
<a href="#gnutls_005fcertificate_005fverify_005fflags">gnutls_certificate_verify_flags</a> and are explained in the table
below.
<p><a name="gnutls_005fcertificate_005fverify_005fflags"></a>
<a name="index-gnutls_005fcertificate_005fverify_005fflags-26"></a>
<dl>
<dt><code>GNUTLS_VERIFY_DISABLE_CA_SIGN:</code><dd>If set a signer does not have to be a certificate authority. This
flag should normaly be disabled, unless you know what this means.
<br><dt><code>GNUTLS_VERIFY_ALLOW_X509_V1_CA_CRT:</code><dd>Allow only trusted CA certificates that have version 1. This is
safer than GNUTLS_VERIFY_ALLOW_ANY_X509_V1_CA_CRT, and should be
used instead. That way only signers in your trusted list will be
allowed to have certificates of version 1.
<br><dt><code>GNUTLS_VERIFY_ALLOW_ANY_X509_V1_CA_CRT:</code><dd>Allow CA certificates that have version 1 (both root and
intermediate). This is dangerous since those haven't the
basicConstraints extension. Must be used in combination with
GNUTLS_VERIFY_ALLOW_X509_V1_CA_CRT.
<br><dt><code>GNUTLS_VERIFY_DO_NOT_ALLOW_SAME:</code><dd>If a certificate is not signed by anyone trusted but exists in
the trusted CA list do not treat it as trusted.
<br><dt><code>GNUTLS_VERIFY_ALLOW_SIGN_RSA_MD2:</code><dd>Allow certificates to be signed using the old MD2 algorithm.
<br><dt><code>GNUTLS_VERIFY_ALLOW_SIGN_RSA_MD5:</code><dd>Allow certificates to be signed using the broken MD5 algorithm.
</dl>
<p>Although the verification of a certificate path indicates that the
certificate is signed by trusted authority, does not reveal anything
about the peer's identity. It is required to verify if the
certificate's owner is the one you expect. For more information consult <!-- %**else if -->
[RFC2818] (See <a href="#Bibliography">RFC2818</a>.)
<p>and section <a href="#ex_003averify">ex:verify</a> for an example.
<div class="node">
<p><hr>
<a name="PKCS-%2310-certificate-requests"></a>
<a name="PKCS-_002310-certificate-requests"></a>
Next: <a rel="next" accesskey="n" href="#PKCS-_002312-structures">PKCS #12 structures</a>,
Previous: <a rel="previous" accesskey="p" href="#Verifying-X_002e509-certificate-paths">Verifying X.509 certificate paths</a>,
Up: <a rel="up" accesskey="u" href="#The-X_002e509-trust-model">The X.509 trust model</a>
</div>
<h4 class="subsection">5.1.3 <acronym>PKCS</acronym> #10 certificate requests</h4>
<p><a name="index-Certificate-requests-27"></a><a name="index-g_t_0040acronym_007bPKCS_007d-_002310-28"></a>
A certificate request is a structure, which contain information about
an applicant of a certificate service. It usually contains a private
key, a distinguished name and secondary data such as a challenge
password. <acronym>GnuTLS</acronym> supports the requests defined in
<acronym>PKCS</acronym> #10 <!-- %**else if -->
[RFC2986] (See <a href="#Bibliography">RFC2986</a>.)
. Other certificate request's format
such as PKIX's <!-- %**else if -->
[RFC2511] (See <a href="#Bibliography">RFC2511</a>.)
are not currently supported.
<p>In <acronym>GnuTLS</acronym> the <acronym>PKCS</acronym> #10 structures are handled
using the <code>gnutls_x509_crq_t</code> type. An example of a certificate
request generation can be found at section <a href="#ex_003acrq">ex:crq</a>.
<div class="node">
<p><hr>
<a name="PKCS-%2312-structures"></a>
<a name="PKCS-_002312-structures"></a>
Previous: <a rel="previous" accesskey="p" href="#PKCS-_002310-certificate-requests">PKCS #10 certificate requests</a>,
Up: <a rel="up" accesskey="u" href="#The-X_002e509-trust-model">The X.509 trust model</a>
</div>
<h4 class="subsection">5.1.4 <acronym>PKCS</acronym> #12 structures</h4>
<p><a name="index-g_t_0040acronym_007bPKCS_007d-_002312-29"></a>
A <acronym>PKCS</acronym> #12 structure <!-- %**else if -->
[PKCS12] (See <a href="#Bibliography">PKCS12</a>.)
usually contains a user's
private keys and certificates. It is commonly used in browsers to
export and import the user's identities.
<p>In <acronym>GnuTLS</acronym> the <acronym>PKCS</acronym> #12 structures are handled
using the <code>gnutls_pkcs12_t</code> type. This is an abstract type that
may hold several <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. An Bag of type encrypted should be decrypted
in order for its data to be accessed.
<p>An example of a <acronym>PKCS</acronym> #12 structure generation can be found
at section <a href="#ex_003apkcs12">ex:pkcs12</a>.
<div class="node">
<p><hr>
<a name="The-OpenPGP-trust-model"></a>
Next: <a rel="next" accesskey="n" href="#Digital-signatures">Digital signatures</a>,
Previous: <a rel="previous" accesskey="p" href="#The-X_002e509-trust-model">The X.509 trust model</a>,
Up: <a rel="up" accesskey="u" href="#More-on-certificate-authentication">More on certificate authentication</a>
</div>
<h3 class="section">5.2 The <acronym>OpenPGP</acronym> trust model</h3>
<p><a name="index-g_t_0040acronym_007bOpenPGP_007d-Keys-30"></a>
The <acronym>OpenPGP</acronym> key authentication relies on a distributed trust
model, called the “web of trust”. The “web of trust” uses a
decentralized system of trusted introducers, which are the same as a
CA. <acronym>OpenPGP</acronym> allows anyone to sign anyone's else public
key. When Alice signs Bob's key, she is introducing Bob's key to
anyone who trusts Alice. If someone trusts Alice to introduce keys,
then Alice is a trusted introducer in the mind of that observer.
<div class="block-image"><img src="pgp1.png" alt="pgp1.png"></div>
<p>For example: If David trusts Alice to be an introducer, and Alice
signed Bob's key, Dave also trusts Bob's key to be the real one.
<p>There are some key points that are important in that model. In the
example Alice has to sign Bob's key, only if she is sure that the key
belongs to Bob. Otherwise she may also make Dave falsely believe that
this is Bob's key. Dave has also the responsibility to know who to
trust. This model is similar to real life relations.
<p>Just see how Charlie behaves in the previous example. Although he has
signed Bob's key - because he knows, somehow, that it belongs to Bob -
he does not trust Bob to be an introducer. Charlie decided to trust
only Kevin, for some reason. A reason could be that Bob is lazy
enough, and signs other people's keys without being sure that they
belong to the actual owner.
<h4 class="subsection">5.2.1 <acronym>OpenPGP</acronym> keys</h4>
<p>In <acronym>GnuTLS</acronym> the <acronym>OpenPGP</acronym> key structures
<!-- %**else if -->
[RFC2440] (See <a href="#Bibliography">RFC2440</a>.)
are handled using the <code>gnutls_openpgp_key_t</code> type
and the corresponding private keys with the
<code>gnutls_openpgp_privkey_t</code> type. All the prototypes for the key
handling functions can be found at <samp><span class="file">gnutls/openpgp.h</span></samp>.
<h4 class="subsection">5.2.2 Verifying an <acronym>OpenPGP</acronym> key</h4>
<p>The verification functions of <acronym>OpenPGP</acronym> keys, included in
<acronym>GnuTLS</acronym>, are simple ones, and do not use the features of the
“web of trust”. For that reason, if the verification needs are
complex, the assistance of external tools like <acronym>GnuPG</acronym> and
GPGME (<a href="http://www.gnupg.org/related_software/gpgme/">http://www.gnupg.org/related_software/gpgme/</a>) is
recommended.
<p>There are two verification functions in <acronym>GnuTLS</acronym>, The
<a href="#gnutls_005fopenpgp_005fkey_005fverify_005fring">gnutls_openpgp_key_verify_ring</a> and the
<a href="#gnutls_005fopenpgp_005fkey_005fverify_005ftrustdb">gnutls_openpgp_key_verify_trustdb</a>. The first one checks an
<acronym>OpenPGP</acronym> key against a given set of public keys (keyring) and
returns the key status. The key verification status is the same as in
<acronym>X.509</acronym> certificates, although the meaning and interpretation are
different. For example an <acronym>OpenPGP</acronym> key may be valid, if the
self signature is ok, even if no signers were found. The meaning of
verification status is shown in the figure below. The latter function
checks a <acronym>GnuPG</acronym> trust database for the given key. This
function does not check the key signatures, only checks for disabled
and revoked keys.
<dl>
<dt><code>CERT_INVALID:</code><dd>A signature on the key is invalid. That means that the key was
modified by somebody, or corrupted during transport.
<br><dt><code>CERT_REVOKED:</code><dd>The key has been revoked by its owner.
<br><dt><code>CERT_SIGNER_NOT_FOUND:</code><dd>The key was not signed by a known signer.
<br><dt><code>GNUTLS_CERT_INSECURE_ALGORITHM:</code><dd>The certificate was signed using an insecure algorithm such as MD2 or MD5.
These algorithms have been broken and should not be trusted.
</dl>
<div class="node">
<p><hr>
<a name="Digital-signatures"></a>
Previous: <a rel="previous" accesskey="p" href="#The-OpenPGP-trust-model">The OpenPGP trust model</a>,
Up: <a rel="up" accesskey="u" href="#More-on-certificate-authentication">More on certificate authentication</a>
</div>
<h3 class="section">5.3 Digital signatures</h3>
<p><a name="index-Digital-signatures-31"></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>Digital signatures work by using somebody'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 € to Greenpeace and find out that he
donated 1.000.000 € to Bad Inc.
<p>For a hash algorithm to be called cryptographic the following three
requirements must hold
<ol type=1 start=1>
<li>Preimage resistance. That means the algorithm must be one way and given
the output of the hash function H(x), it is impossible to
calculate x.
<li>2nd preimage resistance. That means that given a pair x,y with y=H(x) it is impossible
to calculate an x' such that y=H(x').
<li>Collision resistance. That means that it is impossible to calculate random x and x' such
H(x')=H(x).
</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
2^((hash size) / 2)
operations. Today colliding certificates using the MD5 hash algorithm
have been generated as shown in <!-- %**else if -->
[WEGER] (See <a href="#Bibliography">WEGER</a>.)
.
<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 2^64, but it has been showed to
have a collision strength well under 2^50. As of November
2005, it is believed that SHA-1's collision strength is around
2^63. 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 2^63 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.
<h4 class="subsection">5.3.1 Supported algorithms</h4>
<p>The available digital signature algorithms in <acronym>GnuTLS</acronym> are
listed below:
<dl>
<dt><code>RSA</code><dd>RSA is public key cryptosystem designed by Ronald Rivest, Adi Shamir
and Leonard Adleman. It can be used with any hash functions.
<br><dt><code>DSA</code><dd>DSA is the USA's Digital Signature Standard. It uses only the SHA-1
hash algorithm.
</dl>
<p>The supported cryptographic hash algorithms are:
<dl>
<dt><code>MD2</code><dd>MD2 is a cryptographic hash algorithm designed by Ron Rivest. It is
optimized for 8-bit processors. Outputs 128 bits of data. There are no
known weaknesses of this algorithm but since this algorithm is rarely
used and not really studied it should not be used today.
<br><dt><code>MD5</code><dd>MD5 is a cryptographic hash algorithm designed by Ron Rivest. Outputs
128 bits of data. It is considered to be broken.
<br><dt><code>SHA-1</code><dd>SHA is a cryptographic hash algorithm designed by NSA. Outputs 160
bits of data. It is also considered to be broken, though no practical
attacks have been found.
<br><dt><code>RMD160</code><dd>RIPEMD is a cryptographic hash algorithm developed in the framework of
the EU project RIPE. Outputs 160 bits of data.
</dl>
<h4 class="subsection">5.3.2 Trading security for interoperability</h4>
<p>If you connect to a server and use GnuTLS' functions to verify the
certificate chain, and get a <a href="#GNUTLS_005fCERT_005fINSECURE_005fALGORITHM">GNUTLS_CERT_INSECURE_ALGORITHM</a>
validation error (see <a href="#Verifying-X_002e509-certificate-paths">Verifying X.509 certificate paths</a>), it means
that somewhere in the certificate chain there is a certificate signed
using <code>RSA-MD2</code> or <code>RSA-MD5</code>. These two digital signature
algorithms are considered broken, so GnuTLS fail when attempting to
verify 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>First, 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 signed using <code>RSA-MD2</code> or <code>RSA-MD5</code>. The only
attack today is that it is possible to generate certificates with
colliding signatures (collision resistance); you cannot generate a
certificate that has the same signature as an already existing
signature (2nd preimage resistance).
<p>If you are using <a href="#gnutls_005fcertificate_005fverify_005fpeers2">gnutls_certificate_verify_peers2</a> to verify the
certificate chain, you can call
<a href="#gnutls_005fcertificate_005fset_005fverify_005fflags">gnutls_certificate_set_verify_flags</a> with the
<code>GNUTLS_VERIFY_ALLOW_SIGN_RSA_MD2</code> or
<code>GNUTLS_VERIFY_ALLOW_SIGN_RSA_MD5</code> flag, as in:
<pre class="example"> gnutls_certificate_set_verify_flags (x509cred,
GNUTLS_VERIFY_ALLOW_SIGN_RSA_MD5);
</pre>
<p>This will tell the verifier algorithm to enable <code>RSA-MD5</code> when
verifying the certificates.
<p>If you are using <a href="#gnutls_005fx509_005fcrt_005fverify">gnutls_x509_crt_verify</a> or
<a href="#gnutls_005fx509_005fcrt_005flist_005fverify">gnutls_x509_crt_list_verify</a>, you can pass the
<code>GNUTLS_VERIFY_ALLOW_SIGN_RSA_MD5</code> parameter directly in the
<code>flags</code> parameter.
<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 href="#gnutls_005fcertificate_005fget_005fpeers">gnutls_certificate_get_peers</a> to extract
the raw server's certificate chain, then use
<a href="#gnutls_005fx509_005fcrt_005fimport">gnutls_x509_crt_import</a> to parse each of the certificates, and
then use <a 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>GNUTLS_SIGN_RSA_MD2</code> or
<code>GNUTLS_SIGN_RSA_MD5</code>, you could present a warning.
<div class="node">
<p><hr>
<a name="How-to-use-TLS-in-application-protocols"></a>
Next: <a rel="next" accesskey="n" href="#How-to-use-GnuTLS-in-applications">How to use GnuTLS in applications</a>,
Previous: <a rel="previous" accesskey="p" href="#More-on-certificate-authentication">More on certificate authentication</a>,
Up: <a rel="up" accesskey="u" href="#Top">Top</a>
</div>
<h2 class="chapter">6 How to use <acronym>TLS</acronym> in application protocols</h2>
<p>This chapter is intended to provide some hints on how to use the
<acronym>TLS</acronym> over simple custom made application protocols. The
discussion below mainly refers to the <em>TCP/IP</em> transport layer
but may be extended to other ones too.
<ul class="menu">
<li><a accesskey="1" href="#Separate-ports">Separate ports</a>
<li><a accesskey="2" href="#Upward-negotiation">Upward negotiation</a>
</ul>
<div class="node">
<p><hr>
<a name="Separate-ports"></a>
Next: <a rel="next" accesskey="n" href="#Upward-negotiation">Upward negotiation</a>,
Up: <a rel="up" accesskey="u" href="#How-to-use-TLS-in-application-protocols">How to use TLS in application protocols</a>
</div>
<h3 class="section">6.1 Separate ports</h3>
<p>Traditionally <acronym>SSL</acronym> was used in application protocols by
assigning a new port number for the secure services. That way two
separate ports were assigned, one for the non secure sessions, and one
for the secured ones. This has the benefit that if a user requests a
secure session then the client will try to connect to the secure port
and fail otherwise. The only possible attack with this method is a
denial of service one. The most famous example of this method is the
famous “HTTP over TLS” or <acronym>HTTPS</acronym> protocol <!-- %**else if -->
[RFC2818] (See <a href="#Bibliography">RFC2818</a>.)
.
<p>Despite its wide use, this method is not as good as it seems. This
approach starts the <acronym>TLS</acronym> Handshake procedure just after the
client connects on the —so called— secure port. That way the
<acronym>TLS</acronym> protocol does not know anything about the client, and
popular methods like the host advertising in HTTP do not
work<a rel="footnote" href="#fn-14" name="fnd-14"><sup>14</sup></a>. There is no way for the client to say “I
connected to YYY server” before the Handshake starts, so the server
cannot possibly know which certificate to use.
<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 obsoleted.
<div class="node">
<p><hr>
<a name="Upward-negotiation"></a>
Previous: <a rel="previous" accesskey="p" href="#Separate-ports">Separate ports</a>,
Up: <a rel="up" accesskey="u" href="#How-to-use-TLS-in-application-protocols">How to use TLS in application protocols</a>
</div>
<h3 class="section">6.2 Upward negotiation</h3>
<p>Other application protocols<a rel="footnote" href="#fn-15" name="fnd-15"><sup>15</sup></a> use a
different approach to enable the secure layer. They use something
called the “TLS upgrade” method. This method is quite tricky but it
is more flexible. The idea is to extend the application protocol to
have a “STARTTLS” request, whose purpose it to start the TLS
protocols just after the client requests it. This is a really neat
idea and does not require an extra port.
<p>This method is used by almost all modern protocols and there is even
the <!-- %**else if -->
[RFC2817] (See <a href="#Bibliography">RFC2817</a>.)
paper which proposes extensions to HTTP to support
it.
<p>The tricky part, in this method, is that the “STARTTLS” 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 “STARTTLS” capability.
See a typical conversation of a hypothetical protocol:
<blockquote>
(client connects to the server)
<p>CLIENT: HELLO I'M MR. XXX
<p>SERVER: NICE TO MEET YOU XXX
<p>CLIENT: PLEASE START TLS
<p>SERVER: OK
<p>*** TLS STARTS
<p>CLIENT: HERE ARE SOME CONFIDENTIAL DATA
</blockquote>
<p>And see an example of a conversation where someone is acting
in between:
<blockquote>
(client connects to the server)
<p>CLIENT: HELLO I'M MR. XXX
<p>SERVER: NICE TO MEET YOU XXX
<p>CLIENT: PLEASE START TLS
<p>(here someone inserts this message)
<p>SERVER: SORRY I DON'T HAVE THIS CAPABILITY
<p>CLIENT: HERE ARE SOME CONFIDENTIAL DATA
</blockquote>
<p>As you can see above the client was fooled, and was dummy enough to
send the confidential data in the clear.
<p>How to avoid the above attack? As you may have already thought this
one is easy to avoid. The client has to ask the user before it
connects whether the user requests <acronym>TLS</acronym> or not. If the user
answered that he certainly wants the secure layer the last
conversation should be:
<blockquote>
(client connects to the server)
<p>CLIENT: HELLO I'M MR. XXX
<p>SERVER: NICE TO MEET YOU XXX
<p>CLIENT: PLEASE START TLS
<p>(here someone inserts this message)
<p>SERVER: SORRY I DON'T HAVE THIS CAPABILITY
<p>CLIENT: BYE
<p>(the client notifies the user that the secure connection was not possible)
</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 <acronym>TLS</acronym> Handshake protocol
starts, in order to send the correct certificate, use the correct
password file<a rel="footnote" href="#fn-16" name="fnd-16"><sup>16</sup></a>, or anything
else!
<div class="node">
<p><hr>
<a name="How-to-use-GnuTLS-in-applications"></a>
Next: <a rel="next" accesskey="n" href="#Included-programs">Included programs</a>,
Previous: <a rel="previous" accesskey="p" href="#How-to-use-TLS-in-application-protocols">How to use TLS in application protocols</a>,
Up: <a rel="up" accesskey="u" href="#Top">Top</a>
</div>
<h2 class="chapter">7 How to use <acronym>GnuTLS</acronym> in applications</h2>
<p><a name="examples"></a>
<a name="index-Example-programs-32"></a>
<ul class="menu">
<li><a accesskey="1" href="#Preparation">Preparation</a>
<li><a accesskey="2" href="#Multi_002dthreaded-applications">Multi-threaded applications</a>
<li><a accesskey="3" href="#Client-examples">Client examples</a>
<li><a accesskey="4" href="#Server-examples">Server examples</a>
<li><a accesskey="5" href="#Miscellaneous-examples">Miscellaneous examples</a>
<li><a accesskey="6" href="#Compatibility-with-the-OpenSSL-library">Compatibility with the OpenSSL library</a>
</ul>
<div class="node">
<p><hr>
<a name="Preparation"></a>
Next: <a rel="next" accesskey="n" href="#Multi_002dthreaded-applications">Multi-threaded applications</a>,
Up: <a rel="up" accesskey="u" href="#How-to-use-GnuTLS-in-applications">How to use GnuTLS in applications</a>
</div>
<h3 class="section">7.1 Preparation</h3>
<p>To use <acronym>GnuTLS</acronym>, you have to perform some changes to your
sources and your build system. The necessary changes are explained in
the following subsections.
<ul class="menu">
<li><a accesskey="1" href="#Headers">Headers</a>
<li><a accesskey="2" href="#Version-check">Version check</a>
<li><a accesskey="3" href="#Building-the-source">Building the source</a>
</ul>
<div class="node">
<p><hr>
<a name="Headers"></a>
Next: <a rel="next" accesskey="n" href="#Version-check">Version check</a>,
Up: <a rel="up" accesskey="u" href="#Preparation">Preparation</a>
</div>
<h4 class="subsection">7.1.1 Headers</h4>
<p>All the data types and functions of the <acronym>GnuTLS</acronym> library are
defined in the header file <samp><span class="file">gnutls/gnutls.h</span></samp>. This must be
included in all programs that make use of the <acronym>GnuTLS</acronym>
library.
<p>The extra functionality of the <acronym>GnuTLS-extra</acronym> library is
available by including the header file <samp><span class="file">gnutls/extra.h</span></samp> in your
programs.
<div class="node">
<p><hr>
<a name="Version-check"></a>
Next: <a rel="next" accesskey="n" href="#Building-the-source">Building the source</a>,
Previous: <a rel="previous" accesskey="p" href="#Headers">Headers</a>,
Up: <a rel="up" accesskey="u" href="#Preparation">Preparation</a>
</div>
<h4 class="subsection">7.1.2 Version check</h4>
<p>It is often desirable to check that the version of `gnutls' 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 startup.
See the function <a href="#gnutls_005fcheck_005fversion">gnutls_check_version</a>.
<div class="node">
<p><hr>
<a name="Building-the-source"></a>
Previous: <a rel="previous" accesskey="p" href="#Version-check">Version check</a>,
Up: <a rel="up" accesskey="u" href="#Preparation">Preparation</a>
</div>
<h4 class="subsection">7.1.3 Building the source</h4>
<p>If you want to compile a source file including the `gnutls/gnutls.h'
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 -I option).
<p>However, the path to the include file is determined at the time the
source is configured. To solve this problem, <acronym>GnuTLS</acronym> ships
with two small helper programs <samp><span class="command">libgnutls-config</span></samp> and
<samp><span class="command">libgnutls-extra-config</span></samp> that knows about 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 <code>--cflags</code> option to <samp><span class="command">libgnutls-config</span></samp>. The
following example shows how it can be used at the command line:
<pre class="example"> gcc -c foo.c `libgnutls-config --cflags`
</pre>
<p>Adding the output of <samp><span class="command">libgnutls-config --cflags</span></samp> to the
compilers command line will ensure that the compiler can find the
<acronym>GnuTLS</acronym> header file.
<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 -L option). For this, the option <code>--libs</code> to
<samp><span class="command">libgnutls-config</span></samp> can be used. For convenience, this option
also outputs all other options that are required to link the program
with the <acronym>GnuTLS</acronym> libararies. The example shows how to link
`foo.o' with the <acronym>GnuTLS</acronym> libraries to a program <em>foo</em>.
<pre class="example"> gcc -o foo foo.o `libgnutls-config --libs`
</pre>
<p>Of course you can also combine both examples to a single command by
specifying both options to `libgnutls-config':
<pre class="example"> gcc -o foo foo.c `libgnutls-config --cflags --libs`
</pre>
<div class="node">
<p><hr>
<a name="Multi-threaded-applications"></a>
<a name="Multi_002dthreaded-applications"></a>
Next: <a rel="next" accesskey="n" href="#Client-examples">Client examples</a>,
Previous: <a rel="previous" accesskey="p" href="#Preparation">Preparation</a>,
Up: <a rel="up" accesskey="u" href="#How-to-use-GnuTLS-in-applications">How to use GnuTLS in applications</a>
</div>
<h3 class="section">7.2 Multi-threaded applications</h3>
<p>Although the <acronym>GnuTLS</acronym> library is thread safe by design, some
parts of the crypto backend, such as the random generator, are
not. Since <em>libgcrypt 1.1.92</em> there was an automatic detection of
the thread library used by the application, so most applications
wouldn't need to do any changes to ensure thread-safety. Due to the
unportability of the automatic thread detection, this was removed from
later releases of <em>libgcrypt</em>, so applications have now to
register callback functions to ensure proper locking in sensitive
parts of <em>libgcrypt</em>.
<p>There are helper macros to help you properly initialize the libraries.
Examples are shown below.
<ul>
<li>POSIX threads
<pre class="example"> #include <gnutls.h>
#include <gcrypt.h>
#include <errno.h>
#include <pthread.h>
GCRY_THREAD_OPTION_PTHREAD_IMPL;
int main()
{
/* The order matters.
*/
gcry_control (GCRYCTL_SET_THREAD_CBS, &gcry_threads_pthread);
gnutls_global_init();
}
</pre>
<li>GNU PTH threads
<pre class="example"> #include <gnutls.h>
#include <gcrypt.h>
#include <errno.h>
#include <pth.h>
GCRY_THREAD_OPTION_PTH_IMPL;
int main()
{
gcry_control (GCRYCTL_SET_THREAD_CBS, &gcry_threads_pth);
gnutls_global_init();
}
</pre>
<li>Other thread packages
<pre class="example"> /* The gcry_thread_cbs structure must have been
* initialized.
*/
static struct gcry_thread_cbs gcry_threads_other = { ... };
int main()
{
gcry_control (GCRYCTL_SET_THREAD_CBS, &gcry_threads_other);
}
</pre>
</ul>
<div class="node">
<p><hr>
<a name="Client-examples"></a>
Next: <a rel="next" accesskey="n" href="#Server-examples">Server examples</a>,
Previous: <a rel="previous" accesskey="p" href="#Multi_002dthreaded-applications">Multi-threaded applications</a>,
Up: <a rel="up" accesskey="u" href="#How-to-use-GnuTLS-in-applications">How to use GnuTLS in applications</a>
</div>
<h3 class="section">7.3 Client examples</h3>
<p>This section contains examples of <acronym>TLS</acronym> and <acronym>SSL</acronym>
clients, using <acronym>GnuTLS</acronym>. Note that these examples contain
little or no error checking.
<ul class="menu">
<li><a accesskey="1" href="#Simple-client-example-with-anonymous-authentication">Simple client example with anonymous authentication</a>
<li><a accesskey="2" href="#Simple-client-example-with-X_002e509-certificate-support">Simple client example with X.509 certificate support</a>
<li><a accesskey="3" href="#Obtaining-session-information">Obtaining session information</a>
<li><a accesskey="4" href="#Verifying-peer_0027s-certificate">Verifying peer's certificate</a>
<li><a accesskey="5" href="#Using-a-callback-to-select-the-certificate-to-use">Using a callback to select the certificate to use</a>
<li><a accesskey="6" href="#Client-with-Resume-capability-example">Client with Resume capability example</a>
<li><a accesskey="7" href="#Simple-client-example-with-SRP-authentication">Simple client example with SRP authentication</a>
</ul>
<div class="node">
<p><hr>
<a name="Simple-client-example-with-anonymous-authentication"></a>
Next: <a rel="next" accesskey="n" href="#Simple-client-example-with-X_002e509-certificate-support">Simple client example with X.509 certificate support</a>,
Up: <a rel="up" accesskey="u" href="#Client-examples">Client examples</a>
</div>
<h4 class="subsection">7.3.1 Simple client example with anonymous authentication</h4>
<p>The simplest client using TLS is the one that doesn'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 is integrity and privacy protected.
<pre class="verbatim">
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <gnutls/gnutls.h>
/* A very basic TLS client, with anonymous authentication.
*/
#define MAX_BUF 1024
#define SA struct sockaddr
#define MSG "GET / HTTP/1.0\r\n\r\n"
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. */
const int kx_prio[] = { GNUTLS_KX_ANON_DH, 0 };
gnutls_global_init ();
gnutls_anon_allocate_client_credentials (&anoncred);
/* Initialize TLS session
*/
gnutls_init (&session, GNUTLS_CLIENT);
/* Use default priorities */
gnutls_set_default_priority (session);
gnutls_kx_set_priority (session, kx_prio);
/* 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_ptr (session, (gnutls_transport_ptr_t) sd);
/* Perform the TLS handshake
*/
ret = gnutls_handshake (session);
if (ret < 0)
{
fprintf (stderr, "*** Handshake failed\n");
gnutls_perror (ret);
goto end;
}
else
{
printf ("- Handshake was completed\n");
}
gnutls_record_send (session, MSG, strlen (MSG));
ret = gnutls_record_recv (session, buffer, MAX_BUF);
if (ret == 0)
{
printf ("- Peer has closed the TLS connection\n");
goto end;
}
else if (ret < 0)
{
fprintf (stderr, "*** Error: %s\n", gnutls_strerror (ret));
goto end;
}
printf ("- Received %d bytes: ", ret);
for (ii = 0; ii < ret; ii++)
{
fputc (buffer[ii], stdout);
}
fputs ("\n", stdout);
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>
<div class="node">
<p><hr>
<a name="Simple-client-example-with-X.509-certificate-support"></a>
<a name="Simple-client-example-with-X_002e509-certificate-support"></a>
Next: <a rel="next" accesskey="n" href="#Obtaining-session-information">Obtaining session information</a>,
Previous: <a rel="previous" accesskey="p" href="#Simple-client-example-with-anonymous-authentication">Simple client example with anonymous authentication</a>,
Up: <a rel="up" accesskey="u" href="#Client-examples">Client examples</a>
</div>
<h4 class="subsection">7.3.2 Simple client example with <acronym>X.509</acronym> certificate support</h4>
<p>Let's assume now that we want to create a TCP client which
communicates with servers that use <acronym>X.509</acronym> or
<acronym>OpenPGP</acronym> certificate authentication. The following client is
a very simple <acronym>TLS</acronym> client, it does not support session
resuming, not even certificate verification. The TCP functions defined
in this example are used in most of the other examples below, without
redefining them.
<pre class="verbatim">
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <gnutls/gnutls.h>
/* A very basic TLS client, with X.509 authentication.
*/
#define MAX_BUF 1024
#define CAFILE "ca.pem"
#define MSG "GET / HTTP/1.0\r\n\r\n"
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_certificate_credentials_t xcred;
/* Allow connections to servers that have OpenPGP keys as well.
*/
const int cert_type_priority[3] = { GNUTLS_CRT_X509,
GNUTLS_CRT_OPENPGP, 0
};
gnutls_global_init ();
/* X509 stuff */
gnutls_certificate_allocate_credentials (&xcred);
/* sets the trusted cas file
*/
gnutls_certificate_set_x509_trust_file (xcred, CAFILE, GNUTLS_X509_FMT_PEM);
/* Initialize TLS session
*/
gnutls_init (&session, GNUTLS_CLIENT);
/* Use default priorities */
gnutls_set_default_priority (session);
gnutls_certificate_type_set_priority (session, cert_type_priority);
/* put the x509 credentials to the current session
*/
gnutls_credentials_set (session, GNUTLS_CRD_CERTIFICATE, xcred);
/* connect to the peer
*/
sd = tcp_connect ();
gnutls_transport_set_ptr (session, (gnutls_transport_ptr_t) sd);
/* Perform the TLS handshake
*/
ret = gnutls_handshake (session);
if (ret < 0)
{
fprintf (stderr, "*** Handshake failed\n");
gnutls_perror (ret);
goto end;
}
else
{
printf ("- Handshake was completed\n");
}
gnutls_record_send (session, MSG, strlen (MSG));
ret = gnutls_record_recv (session, buffer, MAX_BUF);
if (ret == 0)
{
printf ("- Peer has closed the TLS connection\n");
goto end;
}
else if (ret < 0)
{
fprintf (stderr, "*** Error: %s\n", gnutls_strerror (ret));
goto end;
}
printf ("- Received %d bytes: ", ret);
for (ii = 0; ii < ret; ii++)
{
fputc (buffer[ii], stdout);
}
fputs ("\n", stdout);
gnutls_bye (session, GNUTLS_SHUT_RDWR);
end:
tcp_close (sd);
gnutls_deinit (session);
gnutls_certificate_free_credentials (xcred);
gnutls_global_deinit ();
return 0;
}
</pre>
<div class="node">
<p><hr>
<a name="Obtaining-session-information"></a>
Next: <a rel="next" accesskey="n" href="#Verifying-peer_0027s-certificate">Verifying peer's certificate</a>,
Previous: <a rel="previous" accesskey="p" href="#Simple-client-example-with-X_002e509-certificate-support">Simple client example with X.509 certificate support</a>,
Up: <a rel="up" accesskey="u" href="#Client-examples">Client examples</a>
</div>
<h4 class="subsection">7.3.3 Obtaining session information</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 href="#gnutls_005fhandshake">gnutls_handshake</a>.
<pre class="verbatim">
#include <stdio.h>
#include <stdlib.h>
#include <gnutls/gnutls.h>
#include <gnutls/x509.h>
extern void print_x509_certificate_info (gnutls_session_t);
/* This function will print some details of the
* given session.
*/
int
print_info (gnutls_session_t session)
{
const char *tmp;
gnutls_credentials_type_t cred;
gnutls_kx_algorithm_t kx;
/* print the key exchange's algorithm name
*/
kx = gnutls_kx_get (session);
tmp = gnutls_kx_get_name (kx);
printf ("- Key Exchange: %s\n", tmp);
/* Check the authentication type used and switch
* to the appropriate.
*/
cred = gnutls_auth_get_type (session);
switch (cred)
{
case GNUTLS_CRD_SRP:
printf ("- SRP session with username %s\n",
gnutls_srp_server_get_username (session));
break;
case GNUTLS_CRD_ANON: /* anonymous authentication */
printf ("- Anonymous DH using prime of %d bits\n",
gnutls_dh_get_prime_bits (session));
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)
{
printf ("\n- Ephemeral DH using prime of %d bits\n",
gnutls_dh_get_prime_bits (session));
}
/* if the certificate list is available, then
* print some information about it.
*/
print_x509_certificate_info (session);
} /* switch */
/* print the protocol's name (ie TLS 1.0)
*/
tmp = gnutls_protocol_get_name (gnutls_protocol_get_version (session));
printf ("- Protocol: %s\n", tmp);
/* print the certificate type of the peer.
* ie X.509
*/
tmp =
gnutls_certificate_type_get_name (gnutls_certificate_type_get (session));
printf ("- Certificate Type: %s\n", tmp);
/* print the compression algorithm (if any)
*/
tmp = gnutls_compression_get_name (gnutls_compression_get (session));
printf ("- Compression: %s\n", tmp);
/* print the name of the cipher used.
* ie 3DES.
*/
tmp = gnutls_cipher_get_name (gnutls_cipher_get (session));
printf ("- Cipher: %s\n", tmp);
/* Print the MAC algorithms name.
* ie SHA1
*/
tmp = gnutls_mac_get_name (gnutls_mac_get (session));
printf ("- MAC: %s\n", tmp);
return 0;
}
</pre>
<div class="node">
<p><hr>
<a name="Verifying-peer's-certificate"></a>
<a name="Verifying-peer_0027s-certificate"></a>
Next: <a rel="next" accesskey="n" href="#Using-a-callback-to-select-the-certificate-to-use">Using a callback to select the certificate to use</a>,
Previous: <a rel="previous" accesskey="p" href="#Obtaining-session-information">Obtaining session information</a>,
Up: <a rel="up" accesskey="u" href="#Client-examples">Client examples</a>
</div>
<h4 class="subsection">7.3.4 Verifying peer's certificate</h4>
<p><a name="ex_003averify"></a>
<p>A <acronym>TLS</acronym> session is not secure just after the handshake
procedure has finished. It must be considered secure, only after the
peer's certificate and identity have been verified. That is, you have
to verify the signature in peer's certificate, the hostname in the
certificate, and expiration dates. Just after this step you should
treat the connection as being a secure one.
<pre class="verbatim">#include <stdio.h>
#include <gnutls/gnutls.h>
#include <gnutls/x509.h>
/* This function will try to verify the peer's certificate, and
* also check if the hostname matches, and the activation, expiration dates.
*/
void
verify_certificate (gnutls_session_t session, const char *hostname)
{
unsigned int status;
const gnutls_datum_t *cert_list;
int cert_list_size, ret;
gnutls_x509_crt_t cert;
/* This verification function uses the trusted CAs in the credentials
* structure. So you must have installed one or more CA certificates.
*/
ret = gnutls_certificate_verify_peers2 (session, &status);
if (ret < 0)
{
printf ("Error\n");
return;
}
if (status & GNUTLS_CERT_INVALID)
printf ("The certificate is not trusted.\n");
if (status & GNUTLS_CERT_SIGNER_NOT_FOUND)
printf ("The certificate hasn't got a known issuer.\n");
if (status & GNUTLS_CERT_REVOKED)
printf ("The certificate has been revoked.\n");
/* Up to here the process is the same for X.509 certificates and
* OpenPGP keys. From now on X.509 certificates are assumed. This can
* be easily extended to work with openpgp keys as well.
*/
if (gnutls_certificate_type_get (session) != GNUTLS_CRT_X509)
return;
if (gnutls_x509_crt_init (&cert) < 0)
{
printf ("error in initialization\n");
return;
}
cert_list = gnutls_certificate_get_peers (session, &cert_list_size);
if (cert_list == NULL)
{
printf ("No certificate was found!\n");
return;
}
/* This is not a real world example, since we only check the first
* certificate in the given chain.
*/
if (gnutls_x509_crt_import (cert, &cert_list[0], GNUTLS_X509_FMT_DER) < 0)
{
printf ("error parsing certificate\n");
return;
}
/* Beware here we do not check for errors.
*/
if (gnutls_x509_crt_get_expiration_time (cert) < time (0))
{
printf ("The certificate has expired\n");
return;
}
if (gnutls_x509_crt_get_activation_time (cert) > time (0))
{
printf ("The certificate is not yet activated\n");
return;
}
if (!gnutls_x509_crt_check_hostname (cert, hostname))
{
printf ("The certificate's owner does not match hostname '%s'\n",
hostname);
return;
}
gnutls_x509_crt_deinit (cert);
return;
}
</pre>
An other example is listed below which provides a more detailed
verification output.
<pre class="verbatim">
#include <stdio.h>
#include <stdlib.h>
#include <gnutls/gnutls.h>
#include <gnutls/x509.h>
/* 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 void verify_cert2 (gnutls_x509_crt_t crt,
gnutls_x509_crt_t issuer,
gnutls_x509_crl_t * crl_list, int crl_list_size);
static void verify_last_cert (gnutls_x509_crt_t crt,
gnutls_x509_crt_t * ca_list, int ca_list_size,
gnutls_x509_crl_t * crl_list,
int crl_list_size);
/* This function will try to verify the peer's certificate chain, and
* also check if the hostname matches, and the activation, expiration dates.
*/
void
verify_certificate_chain (gnutls_session_t session,
const char *hostname,
const gnutls_datum_t * cert_chain,
int cert_chain_length)
{
int i;
gnutls_x509_crt_t *cert;
cert = malloc (sizeof (*cert) * cert_chain_length);
/* Import all the certificates in the chain to
* native certificate format.
*/
for (i = 0; i < cert_chain_length; i++)
{
gnutls_x509_crt_init (&cert[i]);
gnutls_x509_crt_import (cert[i], &cert_chain[i], GNUTLS_X509_FMT_DER);
}
/* If the last certificate in the chain is self signed ignore it.
* That is because we want to check against our trusted certificate
* list.
*/
if (gnutls_x509_crt_check_issuer (cert[cert_chain_length - 1],
cert[cert_chain_length - 1]) > 0
&& cert_chain_length > 0)
{
cert_chain_length--;
}
/* Now verify the certificates against their issuers
* in the chain.
*/
for (i = 1; i < cert_chain_length; i++)
{
verify_cert2 (cert[i - 1], cert[i], crl_list, crl_list_size);
}
/* Here we must verify the last certificate in the chain against
* our trusted CA list.
*/
verify_last_cert (cert[cert_chain_length - 1],
ca_list, ca_list_size, crl_list, crl_list_size);
/* Check if the name in the first certificate matches our destination!
*/
if (!gnutls_x509_crt_check_hostname (cert[0], hostname))
{
printf ("The certificate's owner does not match hostname '%s'\n",
hostname);
}
for (i = 0; i < cert_chain_length; i++)
gnutls_x509_crt_deinit (cert[i]);
return;
}
/* Verifies a certificate against an other certificate
* which is supposed to be it's issuer. Also checks the
* crl_list if the certificate is revoked.
*/
static void
verify_cert2 (gnutls_x509_crt_t crt, gnutls_x509_crt_t issuer,
gnutls_x509_crl_t * crl_list, int crl_list_size)
{
unsigned int output;
int ret;
time_t now = time (0);
size_t name_size;
char name[64];
/* Print information about the certificates to
* be checked.
*/
name_size = sizeof (name);
gnutls_x509_crt_get_dn (crt, name, &name_size);
fprintf (stderr, "\nCertificate: %s\n", name);
name_size = sizeof (name);
gnutls_x509_crt_get_issuer_dn (crt, name, &name_size);
fprintf (stderr, "Issued by: %s\n", name);
/* Get the DN of the issuer cert.
*/
name_size = sizeof (name);
gnutls_x509_crt_get_dn (issuer, name, &name_size);
fprintf (stderr, "Checking against: %s\n", name);
/* Do the actual verification.
*/
gnutls_x509_crt_verify (crt, &issuer, 1, 0, &output);
if (output & GNUTLS_CERT_INVALID)
{
fprintf (stderr, "Not trusted");
if (output & GNUTLS_CERT_SIGNER_NOT_FOUND)
fprintf (stderr, ": no issuer was found");
if (output & GNUTLS_CERT_SIGNER_NOT_CA)
fprintf (stderr, ": issuer is not a CA");
fprintf (stderr, "\n");
}
else
fprintf (stderr, "Trusted\n");
/* Now check the expiration dates.
*/
if (gnutls_x509_crt_get_activation_time (crt) > now)
fprintf (stderr, "Not yet activated\n");
if (gnutls_x509_crt_get_expiration_time (crt) < now)
fprintf (stderr, "Expired\n");
/* Check if the certificate is revoked.
*/
ret = gnutls_x509_crt_check_revocation (crt, crl_list, crl_list_size);
if (ret == 1)
{ /* revoked */
fprintf (stderr, "Revoked\n");
}
}
/* Verifies a certificate against our trusted CA list.
* Also checks the crl_list if the certificate is revoked.
*/
static void
verify_last_cert (gnutls_x509_crt_t crt,
gnutls_x509_crt_t * ca_list, int ca_list_size,
gnutls_x509_crl_t * crl_list, int crl_list_size)
{
unsigned int output;
int ret;
time_t now = time (0);
size_t name_size;
char name[64];
/* Print information about the certificates to
* be checked.
*/
name_size = sizeof (name);
gnutls_x509_crt_get_dn (crt, name, &name_size);
fprintf (stderr, "\nCertificate: %s\n", name);
name_size = sizeof (name);
gnutls_x509_crt_get_issuer_dn (crt, name, &name_size);
fprintf (stderr, "Issued by: %s\n", name);
/* Do the actual verification.
*/
gnutls_x509_crt_verify (crt, ca_list, ca_list_size,
GNUTLS_VERIFY_ALLOW_X509_V1_CA_CRT, &output);
if (output & GNUTLS_CERT_INVALID)
{
fprintf (stderr, "Not trusted");
if (output & GNUTLS_CERT_SIGNER_NOT_CA)
fprintf (stderr, ": Issuer is not a CA\n");
else
fprintf (stderr, "\n");
}
else
fprintf (stderr, "Trusted\n");
/* Now check the expiration dates.
*/
if (gnutls_x509_crt_get_activation_time (crt) > now)
fprintf (stderr, "Not yet activated\n");
if (gnutls_x509_crt_get_expiration_time (crt) < now)
fprintf (stderr, "Expired\n");
/* Check if the certificate is revoked.
*/
ret = gnutls_x509_crt_check_revocation (crt, crl_list, crl_list_size);
if (ret == 1)
{ /* revoked */
fprintf (stderr, "Revoked\n");
}
}
</pre>
<div class="node">
<p><hr>
<a name="Using-a-callback-to-select-the-certificate-to-use"></a>
Next: <a rel="next" accesskey="n" href="#Client-with-Resume-capability-example">Client with Resume capability example</a>,
Previous: <a rel="previous" accesskey="p" href="#Verifying-peer_0027s-certificate">Verifying peer's certificate</a>,
Up: <a rel="up" accesskey="u" href="#Client-examples">Client examples</a>
</div>
<h4 class="subsection">7.3.5 Using a callback to select the certificate to use</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.
<pre class="verbatim">
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <sys/stat.h>
#include <gnutls/gnutls.h>
#include <gnutls/x509.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
/* A TLS client that loads the certificate and key.
*/
#define MAX_BUF 1024
#define MSG "GET / HTTP/1.0\r\n\r\n"
#define CERT_FILE "cert.pem"
#define KEY_FILE "key.pem"
#define CAFILE "ca.pem"
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_retr_st * st);
gnutls_x509_crt_t crt;
gnutls_x509_privkey_t key;
/* Helper functions to load a certificate and key
* files into memory.
*/
static gnutls_datum
load_file (const char *file)
{
FILE *f;
gnutls_datum loaded_file = { NULL, 0 };
long filelen;
void *ptr;
if (!(f = fopen(file, "r"))
|| fseek(f, 0, SEEK_END) != 0
|| (filelen = ftell(f)) < 0
|| fseek(f, 0, SEEK_SET) != 0
|| !(ptr = malloc((size_t)filelen))
|| fread(ptr, 1, (size_t)filelen, f) < (size_t)filelen)
{
return loaded_file;
}
loaded_file.data = ptr;
loaded_file.size = (unsigned int)filelen;
return loaded_file;
}
static void unload_file(gnutls_datum data)
{
free(data.data);
}
/* Load the certificate and the private key.
*/
static void
load_keys (void)
{
int ret;
gnutls_datum_t data;
data = load_file (CERT_FILE);
if (data.data == NULL)
{
fprintf (stderr, "*** Error loading cert file.\n");
exit (1);
}
gnutls_x509_crt_init (&crt);
ret = gnutls_x509_crt_import (crt, &data, GNUTLS_X509_FMT_PEM);
if (ret < 0)
{
fprintf (stderr, "*** Error loading key file: %s\n",
gnutls_strerror (ret));
exit (1);
}
unload_file (data);
data = load_file (KEY_FILE);
if (data.data == NULL)
{
fprintf (stderr, "*** Error loading key file.\n");
exit (1);
}
gnutls_x509_privkey_init (&key);
ret = gnutls_x509_privkey_import (key, &data, GNUTLS_X509_FMT_PEM);
if (ret < 0)
{
fprintf (stderr, "*** Error loading key file: %s\n",
gnutls_strerror (ret));
exit (1);
}
unload_file (data);
}
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.
*/
gnutls_global_init ();
load_keys ();
/* X509 stuff */
gnutls_certificate_allocate_credentials (&xcred);
/* sets the trusted cas file
*/
gnutls_certificate_set_x509_trust_file (xcred, CAFILE, GNUTLS_X509_FMT_PEM);
gnutls_certificate_client_set_retrieve_function (xcred, cert_callback);
/* Initialize TLS session
*/
gnutls_init (&session, GNUTLS_CLIENT);
/* Use default priorities */
gnutls_set_default_priority (session);
/* put the x509 credentials to the current session
*/
gnutls_credentials_set (session, GNUTLS_CRD_CERTIFICATE, xcred);
/* connect to the peer
*/
sd = tcp_connect ();
gnutls_transport_set_ptr (session, (gnutls_transport_ptr_t) sd);
/* Perform the TLS handshake
*/
ret = gnutls_handshake (session);
if (ret < 0)
{
fprintf (stderr, "*** Handshake failed\n");
gnutls_perror (ret);
goto end;
}
else
{
printf ("- Handshake was completed\n");
}
gnutls_record_send (session, MSG, strlen (MSG));
ret = gnutls_record_recv (session, buffer, MAX_BUF);
if (ret == 0)
{
printf ("- Peer has closed the TLS connection\n");
goto end;
}
else if (ret < 0)
{
fprintf (stderr, "*** Error: %s\n", gnutls_strerror (ret));
goto end;
}
printf ("- Received %d bytes: ", ret);
for (ii = 0; ii < ret; ii++)
{
fputc (buffer[ii], stdout);
}
fputs ("\n", stdout);
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_retr_st * st)
{
char issuer_dn[256];
int i, ret;
size_t len;
gnutls_certificate_type_t type;
/* Print the server's trusted CAs
*/
if (nreqs > 0)
printf ("- Server's trusted authorities:\n");
else
printf ("- Server did not send us any trusted authorities names.\n");
/* print the names (if any) */
for (i = 0; i < nreqs; i++)
{
len = sizeof (issuer_dn);
ret = gnutls_x509_rdn_get (&req_ca_rdn[i], issuer_dn, &len);
if (ret >= 0)
{
printf (" [%d]: ", i);
printf ("%s\n", issuer_dn);
}
}
/* Select a certificate and return it.
* The certificate must be of any of the "sign algorithms"
* supported by the server.
*/
type = gnutls_certificate_type_get (session);
if (type == GNUTLS_CRT_X509)
{
st->type = type;
st->ncerts = 1;
st->cert.x509 = &crt;
st->key.x509 = key;
st->deinit_all = 0;
}
else
{
return -1;
}
return 0;
}
</pre>
<div class="node">
<p><hr>
<a name="Client-with-Resume-capability-example"></a>
Next: <a rel="next" accesskey="n" href="#Simple-client-example-with-SRP-authentication">Simple client example with SRP authentication</a>,
Previous: <a rel="previous" accesskey="p" href="#Using-a-callback-to-select-the-certificate-to-use">Using a callback to select the certificate to use</a>,
Up: <a rel="up" accesskey="u" href="#Client-examples">Client examples</a>
</div>
<h4 class="subsection">7.3.6 Client with Resume capability example</h4>
<p><a name="ex_003aresume_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 <acronym>TLS</acronym>, close the connection and then try to
establish a new connection using the previously negotiated data.
<pre class="verbatim">#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <gnutls/gnutls.h>
/* 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 CRLFILE "crl.pem"
#define CAFILE "ca.pem"
#define MSG "GET / HTTP/1.0\r\n\r\n"
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;
char *session_data;
size_t session_data_size;
gnutls_global_init ();
/* X509 stuff */
gnutls_certificate_allocate_credentials (&xcred);
gnutls_certificate_set_x509_trust_file (xcred, CAFILE, GNUTLS_X509_FMT_PEM);
for (t = 0; t < 2; t++)
{ /* connect 2 times to the server */
sd = tcp_connect ();
gnutls_init (&session, GNUTLS_CLIENT);
gnutls_set_default_priority (session);
gnutls_credentials_set (session, GNUTLS_CRD_CERTIFICATE, xcred);
if (t > 0)
{
/* if this is not the first time we connect */
gnutls_session_set_data (session, session_data, session_data_size);
free (session_data);
}
gnutls_transport_set_ptr (session, (gnutls_transport_ptr_t) sd);
/* Perform the TLS handshake
*/
ret = gnutls_handshake (session);
if (ret < 0)
{
fprintf (stderr, "*** Handshake failed\n");
gnutls_perror (ret);
goto end;
}
else
{
printf ("- Handshake was completed\n");
}
if (t == 0)
{ /* the first time we connect */
/* get the session data size */
gnutls_session_get_data (session, NULL, &session_data_size);
session_data = malloc (session_data_size);
/* put session data to the session variable */
gnutls_session_get_data (session, session_data, &session_data_size);
}
else
{ /* the second time we connect */
/* check if we actually resumed the previous session */
if (gnutls_session_is_resumed (session) != 0)
{
printf ("- Previous session was resumed\n");
}
else
{
fprintf (stderr, "*** Previous session was NOT resumed\n");
}
}
/* This function was defined in a previous example
*/
/* print_info(session); */
gnutls_record_send (session, MSG, strlen (MSG));
ret = gnutls_record_recv (session, buffer, MAX_BUF);
if (ret == 0)
{
printf ("- Peer has closed the TLS connection\n");
goto end;
}
else if (ret < 0)
{
fprintf (stderr, "*** Error: %s\n", gnutls_strerror (ret));
goto end;
}
printf ("- Received %d bytes: ", ret);
for (ii = 0; ii < ret; ii++)
{
fputc (buffer[ii], stdout);
}
fputs ("\n", 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>
<div class="node">
<p><hr>
<a name="Simple-client-example-with-SRP-authentication"></a>
Previous: <a rel="previous" accesskey="p" href="#Client-with-Resume-capability-example">Client with Resume capability example</a>,
Up: <a rel="up" accesskey="u" href="#Client-examples">Client examples</a>
</div>
<h4 class="subsection">7.3.7 Simple client example with <acronym>SRP</acronym> authentication</h4>
<p>The following client is a very simple <acronym>SRP</acronym> <acronym>TLS</acronym>
client which connects to a server and authenticates using a
<em>username</em> and a <em>password</em>. The server may authenticate
itself using a certificate, and in that case it has to be verified.
<pre class="verbatim">#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <gnutls/gnutls.h>
#include <gnutls/extra.h>
/* 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 "user"
#define PASSWORD "pass"
#define CAFILE "ca.pem"
#define SA struct sockaddr
#define MSG "GET / HTTP/1.0\r\n\r\n"
const int kx_priority[] = { GNUTLS_KX_SRP, GNUTLS_KX_SRP_DSS,
GNUTLS_KX_SRP_RSA, 0
};
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;
gnutls_global_init ();
/* now enable the gnutls-extra library which contains the
* SRP stuff.
*/
gnutls_global_init_extra ();
gnutls_srp_allocate_client_credentials (&srp_cred);
gnutls_certificate_allocate_credentials (&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 (&session, GNUTLS_CLIENT);
/* Set the priorities.
*/
gnutls_set_default_priority (session);
gnutls_kx_set_priority (session, kx_priority);
/* 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_ptr (session, (gnutls_transport_ptr_t) sd);
/* Perform the TLS handshake
*/
ret = gnutls_handshake (session);
if (ret < 0)
{
fprintf (stderr, "*** Handshake failed\n");
gnutls_perror (ret);
goto end;
}
else
{
printf ("- Handshake was completed\n");
}
gnutls_record_send (session, MSG, strlen (MSG));
ret = gnutls_record_recv (session, buffer, MAX_BUF);
if (gnutls_error_is_fatal (ret) == 1 || ret == 0)
{
if (ret == 0)
{
printf ("- Peer has closed the GNUTLS connection\n");
goto end;
}
else
{
fprintf (stderr, "*** Error: %s\n", gnutls_strerror (ret));
goto end;
}
}
else
check_alert (session, ret);
if (ret > 0)
{
printf ("- Received %d bytes: ", ret);
for (ii = 0; ii < ret; ii++)
{
fputc (buffer[ii], stdout);
}
fputs ("\n", 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>
<div class="node">
<p><hr>
<a name="Server-examples"></a>
Next: <a rel="next" accesskey="n" href="#Miscellaneous-examples">Miscellaneous examples</a>,
Previous: <a rel="previous" accesskey="p" href="#Client-examples">Client examples</a>,
Up: <a rel="up" accesskey="u" href="#How-to-use-GnuTLS-in-applications">How to use GnuTLS in applications</a>
</div>
<h3 class="section">7.4 Server examples</h3>
<p>This section contains examples of <acronym>TLS</acronym> and <acronym>SSL</acronym>
servers, using <acronym>GnuTLS</acronym>.
<ul class="menu">
<li><a accesskey="1" href="#Echo-Server-with-X_002e509-authentication">Echo Server with X.509 authentication</a>
<li><a accesskey="2" href="#Echo-Server-with-X_002e509-authentication-II">Echo Server with X.509 authentication II</a>
<li><a accesskey="3" href="#Echo-Server-with-OpenPGP-authentication">Echo Server with OpenPGP authentication</a>
<li><a accesskey="4" href="#Echo-Server-with-SRP-authentication">Echo Server with SRP authentication</a>
<li><a accesskey="5" href="#Echo-Server-with-anonymous-authentication">Echo Server with anonymous authentication</a>
</ul>
<div class="node">
<p><hr>
<a name="Echo-Server-with-X.509-authentication"></a>
<a name="Echo-Server-with-X_002e509-authentication"></a>
Next: <a rel="next" accesskey="n" href="#Echo-Server-with-X_002e509-authentication-II">Echo Server with X.509 authentication II</a>,
Up: <a rel="up" accesskey="u" href="#Server-examples">Server examples</a>
</div>
<h4 class="subsection">7.4.1 Echo Server with <acronym>X.509</acronym> authentication</h4>
<p>This example is a very simple echo server which supports
<acronym>X.509</acronym> authentication, using the RSA ciphersuites.
<pre class="verbatim">
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
#include <unistd.h>
#include <gnutls/gnutls.h>
#define KEYFILE "key.pem"
#define CERTFILE "cert.pem"
#define CAFILE "ca.pem"
#define CRLFILE "crl.pem"
/* This is a sample TLS 1.0 echo server, using X.509 authentication.
*/
#define SA struct sockaddr
#define SOCKET_ERR(err,s) if(err==-1) {perror(s);return(1);}
#define MAX_BUF 1024
#define PORT 5556 /* listen to 5556 port */
#define DH_BITS 1024
/* These are global */
gnutls_certificate_credentials_t x509_cred;
gnutls_session_t
initialize_tls_session (void)
{
gnutls_session_t session;
gnutls_init (&session, GNUTLS_SERVER);
/* avoid calling all the priority functions, since the defaults
* are adequate.
*/
gnutls_set_default_priority (session);
gnutls_credentials_set (session, GNUTLS_CRD_CERTIFICATE, x509_cred);
/* request client certificate if any.
*/
gnutls_certificate_server_set_request (session, GNUTLS_CERT_REQUEST);
gnutls_dh_set_prime_bits (session, DH_BITS);
return session;
}
static gnutls_dh_params_t dh_params;
static int
generate_dh_params (void)
{
/* Generate Diffie Hellman parameters - for use with DHE
* kx algorithms. These should be discarded and regenerated
* once a day, once a week or once a month. Depending on the
* security requirements.
*/
gnutls_dh_params_init (&dh_params);
gnutls_dh_params_generate2 (dh_params, DH_BITS);
return 0;
}
int
main (void)
{
int err, listen_sd, i;
int sd, ret;
struct sockaddr_in sa_serv;
struct sockaddr_in sa_cli;
int client_len;
char topbuf[512];
gnutls_session_t session;
char buffer[MAX_BUF + 1];
int optval = 1;
/* this must be called once in the program
*/
gnutls_global_init ();
gnutls_certificate_allocate_credentials (&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);
generate_dh_params ();
gnutls_certificate_set_dh_params (x509_cred, dh_params);
/* Socket operations
*/
listen_sd = socket (AF_INET, SOCK_STREAM, 0);
SOCKET_ERR (listen_sd, "socket");
memset (&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, &optval, sizeof (int));
err = bind (listen_sd, (SA *) & sa_serv, sizeof (sa_serv));
SOCKET_ERR (err, "bind");
err = listen (listen_sd, 1024);
SOCKET_ERR (err, "listen");
printf ("Server ready. Listening to port '%d'.\n\n", PORT);
client_len = sizeof (sa_cli);
for (;;)
{
session = initialize_tls_session ();
sd = accept (listen_sd, (SA *) & sa_cli, &client_len);
printf ("- connection from %s, port %d\n",
inet_ntop (AF_INET, &sa_cli.sin_addr, topbuf,
sizeof (topbuf)), ntohs (sa_cli.sin_port));
gnutls_transport_set_ptr (session, (gnutls_transport_ptr_t) sd);
ret = gnutls_handshake (session);
if (ret < 0)
{
close (sd);
gnutls_deinit (session);
fprintf (stderr, "*** Handshake has failed (%s)\n\n",
gnutls_strerror (ret));
continue;
}
printf ("- Handshake was completed\n");
/* see the Getting peer's information example */
/* print_info(session); */
i = 0;
for (;;)
{
memset (buffer, 0, MAX_BUF + 1);
ret = gnutls_record_recv (session, buffer, MAX_BUF);
if (ret == 0)
{
printf ("\n- Peer has closed the GNUTLS connection\n");
break;
}
else if (ret < 0)
{
fprintf (stderr, "\n*** Received corrupted "
"data(%d). Closing the connection.\n\n", ret);
break;
}
else if (ret > 0)
{
/* echo data back to the client
*/
gnutls_record_send (session, buffer, strlen (buffer));
}
}
printf ("\n");
/* 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_certificate_free_credentials (x509_cred);
gnutls_global_deinit ();
return 0;
}
</pre>
<div class="node">
<p><hr>
<a name="Echo-Server-with-X.509-authentication-II"></a>
<a name="Echo-Server-with-X_002e509-authentication-II"></a>
Next: <a rel="next" accesskey="n" href="#Echo-Server-with-OpenPGP-authentication">Echo Server with OpenPGP authentication</a>,
Previous: <a rel="previous" accesskey="p" href="#Echo-Server-with-X_002e509-authentication">Echo Server with X.509 authentication</a>,
Up: <a rel="up" accesskey="u" href="#Server-examples">Server examples</a>
</div>
<h4 class="subsection">7.4.2 Echo Server with <acronym>X.509</acronym> authentication II</h4>
<p>The following example is a server which supports <acronym>X.509</acronym>
authentication. This server supports the export-grade cipher suites,
the DHE ciphersuites and session resuming.
<pre class="verbatim">
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
#include <unistd.h>
#include <gnutls/gnutls.h>
#define KEYFILE "key.pem"
#define CERTFILE "cert.pem"
#define CAFILE "ca.pem"
#define CRLFILE "crl.pem"
/* This is a sample TLS 1.0 echo server.
* Export-grade ciphersuites and session resuming are supported.
*/
#define SA struct sockaddr
#define SOCKET_ERR(err,s) if(err==-1) {perror(s);return(1);}
#define MAX_BUF 1024
#define PORT 5556 /* listen to 5556 port */
#define DH_BITS 1024
/* These are global */
gnutls_certificate_credentials_t cert_cred;
static void wrap_db_init (void);
static void wrap_db_deinit (void);
static int wrap_db_store (void *dbf, gnutls_datum_t key, gnutls_datum_t data);
static gnutls_datum_t wrap_db_fetch (void *dbf, gnutls_datum_t key);
static int wrap_db_delete (void *dbf, gnutls_datum_t key);
#define TLS_SESSION_CACHE 50
gnutls_session_t
initialize_tls_session (void)
{
gnutls_session_t session;
gnutls_init (&session, GNUTLS_SERVER);
/* Use the default priorities, plus, export cipher suites.
*/
gnutls_set_default_export_priority (session);
gnutls_credentials_set (session, GNUTLS_CRD_CERTIFICATE, cert_cred);
/* request client certificate if any.
*/
gnutls_certificate_server_set_request (session, GNUTLS_CERT_REQUEST);
gnutls_dh_set_prime_bits (session, DH_BITS);
if (TLS_SESSION_CACHE != 0)
{
gnutls_db_set_retrieve_function (session, wrap_db_fetch);
gnutls_db_set_remove_function (session, wrap_db_delete);
gnutls_db_set_store_function (session, wrap_db_store);
gnutls_db_set_ptr (session, NULL);
}
return session;
}
gnutls_dh_params_t dh_params;
/* Export-grade cipher suites require temporary RSA
* keys.
*/
gnutls_rsa_params_t rsa_params;
int
generate_dh_params (void)
{
/* Generate Diffie Hellman parameters - for use with DHE
* kx algorithms. These should be discarded and regenerated
* once a day, once a week or once a month. Depends on the
* security requirements.
*/
gnutls_dh_params_init (&dh_params);
gnutls_dh_params_generate2 (dh_params, DH_BITS);
return 0;
}
static int
generate_rsa_params (void)
{
gnutls_rsa_params_init (&rsa_params);
/* Generate RSA parameters - for use with RSA-export
* cipher suites. These should be discarded and regenerated
* once a day, once every 500 transactions etc. Depends on the
* security requirements.
*/
gnutls_rsa_params_generate2 (rsa_params, 512);
return 0;
}
int
main (void)
{
int err, listen_sd, i;
int sd, ret;
struct sockaddr_in sa_serv;
struct sockaddr_in sa_cli;
int client_len;
char topbuf[512];
gnutls_session_t session;
char buffer[MAX_BUF + 1];
int optval = 1;
char name[256];
strcpy (name, "Echo Server");
/* this must be called once in the program
*/
gnutls_global_init ();
gnutls_certificate_allocate_credentials (&cert_cred);
gnutls_certificate_set_x509_trust_file (cert_cred, CAFILE,
GNUTLS_X509_FMT_PEM);
gnutls_certificate_set_x509_crl_file (cert_cred, CRLFILE,
GNUTLS_X509_FMT_PEM);
gnutls_certificate_set_x509_key_file (cert_cred, CERTFILE, KEYFILE,
GNUTLS_X509_FMT_PEM);
generate_dh_params ();
generate_rsa_params ();
if (TLS_SESSION_CACHE != 0)
{
wrap_db_init ();
}
gnutls_certificate_set_dh_params (cert_cred, dh_params);
gnutls_certificate_set_rsa_export_params (cert_cred, rsa_params);
/* Socket operations
*/
listen_sd = socket (AF_INET, SOCK_STREAM, 0);
SOCKET_ERR (listen_sd, "socket");
memset (&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, &optval, sizeof (int));
err = bind (listen_sd, (SA *) & sa_serv, sizeof (sa_serv));
SOCKET_ERR (err, "bind");
err = listen (listen_sd, 1024);
SOCKET_ERR (err, "listen");
printf ("%s ready. Listening to port '%d'.\n\n", name, PORT);
client_len = sizeof (sa_cli);
for (;;)
{
session = initialize_tls_session ();
sd = accept (listen_sd, (SA *) & sa_cli, &client_len);
printf ("- connection from %s, port %d\n",
inet_ntop (AF_INET, &sa_cli.sin_addr, topbuf,
sizeof (topbuf)), ntohs (sa_cli.sin_port));
gnutls_transport_set_ptr (session, (gnutls_transport_ptr_t) sd);
ret = gnutls_handshake (session);
if (ret < 0)
{
close (sd);
gnutls_deinit (session);
fprintf (stderr, "*** Handshake has failed (%s)\n\n",
gnutls_strerror (ret));
continue;
}
printf ("- Handshake was completed\n");
/* print_info(session); */
i = 0;
for (;;)
{
memset (buffer, 0, MAX_BUF + 1);
ret = gnutls_record_recv (session, buffer, MAX_BUF);
if (ret == 0)
{
printf ("\n- Peer has closed the TLS connection\n");
break;
}
else if (ret < 0)
{
fprintf (stderr, "\n*** Received corrupted "
"data(%d). Closing the connection.\n\n", ret);
break;
}
else if (ret > 0)
{
/* echo data back to the client
*/
gnutls_record_send (session, buffer, strlen (buffer));
}
}
printf ("\n");
/* 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_certificate_free_credentials (cert_cred);
gnutls_global_deinit ();
return 0;
}
/* Functions and other stuff needed for session resuming.
* This is done using a very simple list which holds session ids
* and session data.
*/
#define MAX_SESSION_ID_SIZE 32
#define MAX_SESSION_DATA_SIZE 512
typedef struct
{
char session_id[MAX_SESSION_ID_SIZE];
int session_id_size;
char session_data[MAX_SESSION_DATA_SIZE];
int session_data_size;
} CACHE;
static CACHE *cache_db;
static int cache_db_ptr = 0;
static void
wrap_db_init (void)
{
/* allocate cache_db */
cache_db = calloc (1, TLS_SESSION_CACHE * sizeof (CACHE));
}
static void
wrap_db_deinit (void)
{
return;
}
static int
wrap_db_store (void *dbf, gnutls_datum_t key, gnutls_datum_t data)
{
if (cache_db == NULL)
return -1;
if (key.size > MAX_SESSION_ID_SIZE)
return -1;
if (data.size > MAX_SESSION_DATA_SIZE)
return -1;
memcpy (cache_db[cache_db_ptr].session_id, key.data, key.size);
cache_db[cache_db_ptr].session_id_size = key.size;
memcpy (cache_db[cache_db_ptr].session_data, data.data, data.size);
cache_db[cache_db_ptr].session_data_size = data.size;
cache_db_ptr++;
cache_db_ptr %= TLS_SESSION_CACHE;
return 0;
}
static gnutls_datum_t
wrap_db_fetch (void *dbf, gnutls_datum_t key)
{
gnutls_datum_t res = { NULL, 0 };
int i;
if (cache_db == NULL)
return res;
for (i = 0; i < TLS_SESSION_CACHE; i++)
{
if (key.size == cache_db[i].session_id_size &&
memcmp (key.data, cache_db[i].session_id, key.size) == 0)
{
res.size = cache_db[i].session_data_size;
res.data = gnutls_malloc (res.size);
if (res.data == NULL)
return res;
memcpy (res.data, cache_db[i].session_data, res.size);
return res;
}
}
return res;
}
static int
wrap_db_delete (void *dbf, gnutls_datum_t key)
{
int i;
if (cache_db == NULL)
return -1;
for (i = 0; i < TLS_SESSION_CACHE; i++)
{
if (key.size == cache_db[i].session_id_size &&
memcmp (key.data, cache_db[i].session_id, key.size) == 0)
{
cache_db[i].session_id_size = 0;
cache_db[i].session_data_size = 0;
return 0;
}
}
return -1;
}
</pre>
<div class="node">
<p><hr>
<a name="Echo-Server-with-OpenPGP-authentication"></a>
Next: <a rel="next" accesskey="n" href="#Echo-Server-with-SRP-authentication">Echo Server with SRP authentication</a>,
Previous: <a rel="previous" accesskey="p" href="#Echo-Server-with-X_002e509-authentication-II">Echo Server with X.509 authentication II</a>,
Up: <a rel="up" accesskey="u" href="#Server-examples">Server examples</a>
</div>
<h4 class="subsection">7.4.3 Echo Server with <acronym>OpenPGP</acronym> authentication</h4>
<p><a name="index-g_t_0040acronym_007bOpenPGP_007d-Server-33"></a>
The following example is an echo server which supports
<acronym><acronym>OpenPGP</acronym></acronym> key authentication. You can easily combine
this functionality —that is have a server that supports both
<acronym>X.509</acronym> and <acronym>OpenPGP</acronym> certificates— but we separated
them to keep these examples as simple as possible.
<pre class="verbatim">
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
#include <unistd.h>
#include <gnutls/gnutls.h>
/* Must be linked against gnutls-extra.
*/
#include <gnutls/extra.h>
#define KEYFILE "secret.asc"
#define CERTFILE "public.asc"
#define RINGFILE "ring.gpg"
/* This is a sample TLS 1.0-OpenPGP echo server.
*/
#define SA struct sockaddr
#define SOCKET_ERR(err,s) if(err==-1) {perror(s);return(1);}
#define MAX_BUF 1024
#define PORT 5556 /* listen to 5556 port */
#define DH_BITS 1024
/* These are global */
gnutls_certificate_credentials_t cred;
const int cert_type_priority[2] = { GNUTLS_CRT_OPENPGP, 0 };
gnutls_dh_params_t dh_params;
static int
generate_dh_params (void)
{
/* Generate Diffie Hellman parameters - for use with DHE
* kx algorithms. These should be discarded and regenerated
* once a day, once a week or once a month. Depending on the
* security requirements.
*/
gnutls_dh_params_init (&dh_params);
gnutls_dh_params_generate2 (dh_params, DH_BITS);
return 0;
}
/* These are global */
gnutls_certificate_credentials_t x509_cred;
gnutls_session_t
initialize_tls_session (void)
{
gnutls_session_t session;
gnutls_init (&session, GNUTLS_SERVER);
/* avoid calling all the priority functions, since the defaults
* are adequate.
*/
gnutls_set_default_priority (session);
gnutls_credentials_set (session, GNUTLS_CRD_CERTIFICATE, x509_cred);
/* request client certificate if any.
*/
gnutls_certificate_server_set_request (session, GNUTLS_CERT_REQUEST);
gnutls_dh_set_prime_bits (session, DH_BITS);
return session;
}
int
main (void)
{
int err, listen_sd, i;
int sd, ret;
struct sockaddr_in sa_serv;
struct sockaddr_in sa_cli;
int client_len;
char topbuf[512];
gnutls_session_t session;
char buffer[MAX_BUF + 1];
int optval = 1;
char name[256];
strcpy (name, "Echo Server");
/* this must be called once in the program
*/
gnutls_global_init ();
gnutls_certificate_allocate_credentials (&cred);
gnutls_certificate_set_openpgp_keyring_file (cred, RINGFILE);
gnutls_certificate_set_openpgp_key_file (cred, CERTFILE, KEYFILE);
generate_dh_params ();
gnutls_certificate_set_dh_params (cred, dh_params);
/* Socket operations
*/
listen_sd = socket (AF_INET, SOCK_STREAM, 0);
SOCKET_ERR (listen_sd, "socket");
memset (&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, &optval, sizeof (int));
err = bind (listen_sd, (SA *) & sa_serv, sizeof (sa_serv));
SOCKET_ERR (err, "bind");
err = listen (listen_sd, 1024);
SOCKET_ERR (err, "listen");
printf ("%s ready. Listening to port '%d'.\n\n", name, PORT);
client_len = sizeof (sa_cli);
for (;;)
{
session = initialize_tls_session ();
gnutls_certificate_type_set_priority (session, cert_type_priority);
sd = accept (listen_sd, (SA *) & sa_cli, &client_len);
printf ("- connection from %s, port %d\n",
inet_ntop (AF_INET, &sa_cli.sin_addr, topbuf,
sizeof (topbuf)), ntohs (sa_cli.sin_port));
gnutls_transport_set_ptr (session, (gnutls_transport_ptr_t) sd);
ret = gnutls_handshake (session);
if (ret < 0)
{
close (sd);
gnutls_deinit (session);
fprintf (stderr, "*** Handshake has failed (%s)\n\n",
gnutls_strerror (ret));
continue;
}
printf ("- Handshake was completed\n");
/* see the Getting peer's information example */
/* print_info(session); */
i = 0;
for (;;)
{
memset (buffer, 0, MAX_BUF + 1);
ret = gnutls_record_recv (session, buffer, MAX_BUF);
if (ret == 0)
{
printf ("\n- Peer has closed the GNUTLS connection\n");
break;
}
else if (ret < 0)
{
fprintf (stderr, "\n*** Received corrupted "
"data(%d). Closing the connection.\n\n", ret);
break;
}
else if (ret > 0)
{
/* echo data back to the client
*/
gnutls_record_send (session, buffer, strlen (buffer));
}
}
printf ("\n");
/* 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_certificate_free_credentials (cred);
gnutls_global_deinit ();
return 0;
}
</pre>
<div class="node">
<p><hr>
<a name="Echo-Server-with-SRP-authentication"></a>
Next: <a rel="next" accesskey="n" href="#Echo-Server-with-anonymous-authentication">Echo Server with anonymous authentication</a>,
Previous: <a rel="previous" accesskey="p" href="#Echo-Server-with-OpenPGP-authentication">Echo Server with OpenPGP authentication</a>,
Up: <a rel="up" accesskey="u" href="#Server-examples">Server examples</a>
</div>
<h4 class="subsection">7.4.4 Echo Server with <acronym>SRP</acronym> authentication</h4>
<p>This is a server which supports <acronym>SRP</acronym> authentication. It is
also possible to combine this functionality with a certificate
server. Here it is separate for simplicity.
<pre class="verbatim">
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
#include <unistd.h>
#include <gnutls/gnutls.h>
#include <gnutls/extra.h>
#define SRP_PASSWD "tpasswd"
#define SRP_PASSWD_CONF "tpasswd.conf"
#define KEYFILE "key.pem"
#define CERTFILE "cert.pem"
#define CAFILE "ca.pem"
/* This is a sample TLS-SRP echo server.
*/
#define SA struct sockaddr
#define SOCKET_ERR(err,s) if(err==-1) {perror(s);return(1);}
#define MAX_BUF 1024
#define PORT 5556 /* listen to 5556 port */
/* These are global */
gnutls_srp_server_credentials_t srp_cred;
gnutls_certificate_credentials_t cert_cred;
gnutls_session_t
initialize_tls_session (void)
{
gnutls_session_t session;
const int kx_priority[] = { GNUTLS_KX_SRP, GNUTLS_KX_SRP_DSS,
GNUTLS_KX_SRP_RSA, 0
};
gnutls_init (&session, GNUTLS_SERVER);
gnutls_set_default_priority (session);
gnutls_kx_set_priority (session, kx_priority);
gnutls_credentials_set (session, GNUTLS_CRD_SRP, srp_cred);
/* for the certificate authenticated ciphersuites.
*/
gnutls_credentials_set (session, GNUTLS_CRD_CERTIFICATE, cert_cred);
/* request client certificate if any.
*/
gnutls_certificate_server_set_request (session, GNUTLS_CERT_IGNORE);
return session;
}
int
main (void)
{
int err, listen_sd, i;
int sd, ret;
struct sockaddr_in sa_serv;
struct sockaddr_in sa_cli;
int client_len;
char topbuf[512];
gnutls_session_t session;
char buffer[MAX_BUF + 1];
int optval = 1;
char name[256];
strcpy (name, "Echo Server");
/* these must be called once in the program
*/
gnutls_global_init ();
gnutls_global_init_extra (); /* for SRP */
/* SRP_PASSWD a password file (created with the included srptool utility)
*/
gnutls_srp_allocate_server_credentials (&srp_cred);
gnutls_srp_set_server_credentials_file (srp_cred, SRP_PASSWD,
SRP_PASSWD_CONF);
gnutls_certificate_allocate_credentials (&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, "socket");
memset (&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, &optval, sizeof (int));
err = bind (listen_sd, (SA *) & sa_serv, sizeof (sa_serv));
SOCKET_ERR (err, "bind");
err = listen (listen_sd, 1024);
SOCKET_ERR (err, "listen");
printf ("%s ready. Listening to port '%d'.\n\n", name, PORT);
client_len = sizeof (sa_cli);
for (;;)
{
session = initialize_tls_session ();
sd = accept (listen_sd, (SA *) & sa_cli, &client_len);
printf ("- connection from %s, port %d\n",
inet_ntop (AF_INET, &sa_cli.sin_addr, topbuf,
sizeof (topbuf)), ntohs (sa_cli.sin_port));
gnutls_transport_set_ptr (session, (gnutls_transport_ptr_t) sd);
ret = gnutls_handshake (session);
if (ret < 0)
{
close (sd);
gnutls_deinit (session);
fprintf (stderr, "*** Handshake has failed (%s)\n\n",
gnutls_strerror (ret));
continue;
}
printf ("- Handshake was completed\n");
/* print_info(session); */
i = 0;
for (;;)
{
memset (buffer, 0, MAX_BUF + 1);
ret = gnutls_record_recv (session, buffer, MAX_BUF);
if (ret == 0)
{
printf ("\n- Peer has closed the GNUTLS connection\n");
break;
}
else if (ret < 0)
{
fprintf (stderr, "\n*** Received corrupted "
"data(%d). Closing the connection.\n\n", ret);
break;
}
else if (ret > 0)
{
/* echo data back to the client
*/
gnutls_record_send (session, buffer, strlen (buffer));
}
}
printf ("\n");
/* 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_srp_free_server_credentials (srp_cred);
gnutls_certificate_free_credentials (cert_cred);
gnutls_global_deinit ();
return 0;
}
</pre>
<div class="node">
<p><hr>
<a name="Echo-Server-with-anonymous-authentication"></a>
Previous: <a rel="previous" accesskey="p" href="#Echo-Server-with-SRP-authentication">Echo Server with SRP authentication</a>,
Up: <a rel="up" accesskey="u" href="#Server-examples">Server examples</a>
</div>
<h4 class="subsection">7.4.5 Echo Server with anonymous authentication</h4>
<p>This example server support anonymous authentication, and could be
used to serve the example client for anonymous authentication.
<pre class="verbatim">
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
#include <unistd.h>
#include <gnutls/gnutls.h>
/* This is a sample TLS 1.0 echo server, for anonymous authentication only.
*/
#define SA struct sockaddr
#define SOCKET_ERR(err,s) if(err==-1) {perror(s);return(1);}
#define MAX_BUF 1024
#define PORT 5556 /* listen to 5556 port */
#define DH_BITS 1024
/* These are global */
gnutls_anon_server_credentials_t anoncred;
gnutls_session_t
initialize_tls_session (void)
{
gnutls_session_t session;
const int kx_prio[] = { GNUTLS_KX_ANON_DH, 0 };
gnutls_init (&session, GNUTLS_SERVER);
/* avoid calling all the priority functions, since the defaults
* are adequate.
*/
gnutls_set_default_priority (session);
gnutls_kx_set_priority (session, kx_prio);
gnutls_credentials_set (session, GNUTLS_CRD_ANON, anoncred);
gnutls_dh_set_prime_bits (session, DH_BITS);
return session;
}
static gnutls_dh_params_t dh_params;
static int
generate_dh_params (void)
{
/* Generate Diffie Hellman parameters - for use with DHE
* kx algorithms. These should be discarded and regenerated
* once a day, once a week or once a month. Depending on the
* security requirements.
*/
gnutls_dh_params_init (&dh_params);
gnutls_dh_params_generate2 (dh_params, DH_BITS);
return 0;
}
int
main (void)
{
int err, listen_sd, i;
int sd, ret;
struct sockaddr_in sa_serv;
struct sockaddr_in sa_cli;
int client_len;
char topbuf[512];
gnutls_session_t session;
char buffer[MAX_BUF + 1];
int optval = 1;
/* this must be called once in the program
*/
gnutls_global_init ();
gnutls_anon_allocate_server_credentials (&anoncred);
generate_dh_params ();
gnutls_anon_set_server_dh_params (anoncred, dh_params);
/* Socket operations
*/
listen_sd = socket (AF_INET, SOCK_STREAM, 0);
SOCKET_ERR (listen_sd, "socket");
memset (&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, &optval, sizeof (int));
err = bind (listen_sd, (SA *) & sa_serv, sizeof (sa_serv));
SOCKET_ERR (err, "bind");
err = listen (listen_sd, 1024);
SOCKET_ERR (err, "listen");
printf ("Server ready. Listening to port '%d'.\n\n", PORT);
client_len = sizeof (sa_cli);
for (;;)
{
session = initialize_tls_session ();
sd = accept (listen_sd, (SA *) & sa_cli, &client_len);
printf ("- connection from %s, port %d\n",
inet_ntop (AF_INET, &sa_cli.sin_addr, topbuf,
sizeof (topbuf)), ntohs (sa_cli.sin_port));
gnutls_transport_set_ptr (session, (gnutls_transport_ptr_t) sd);
ret = gnutls_handshake (session);
if (ret < 0)
{
close (sd);
gnutls_deinit (session);
fprintf (stderr, "*** Handshake has failed (%s)\n\n",
gnutls_strerror (ret));
continue;
}
printf ("- Handshake was completed\n");
/* see the Getting peer's information example */
/* print_info(session); */
i = 0;
for (;;)
{
memset (buffer, 0, MAX_BUF + 1);
ret = gnutls_record_recv (session, buffer, MAX_BUF);
if (ret == 0)
{
printf ("\n- Peer has closed the GNUTLS connection\n");
break;
}
else if (ret < 0)
{
fprintf (stderr, "\n*** Received corrupted "
"data(%d). Closing the connection.\n\n", ret);
break;
}
else if (ret > 0)
{
/* echo data back to the client
*/
gnutls_record_send (session, buffer, strlen (buffer));
}
}
printf ("\n");
/* 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>
<div class="node">
<p><hr>
<a name="Miscellaneous-examples"></a>
Next: <a rel="next" accesskey="n" href="#Compatibility-with-the-OpenSSL-library">Compatibility with the OpenSSL library</a>,
Previous: <a rel="previous" accesskey="p" href="#Server-examples">Server examples</a>,
Up: <a rel="up" accesskey="u" href="#How-to-use-GnuTLS-in-applications">How to use GnuTLS in applications</a>
</div>
<h3 class="section">7.5 Miscellaneous examples</h3>
<ul class="menu">
<li><a accesskey="1" href="#Checking-for-an-alert">Checking for an alert</a>
<li><a accesskey="2" href="#X_002e509-certificate-parsing-example">X.509 certificate parsing example</a>
<li><a accesskey="3" href="#Certificate-request-generation">Certificate request generation</a>
<li><a accesskey="4" href="#PKCS-_002312-structure-generation">PKCS #12 structure generation</a>
</ul>
<div class="node">
<p><hr>
<a name="Checking-for-an-alert"></a>
Next: <a rel="next" accesskey="n" href="#X_002e509-certificate-parsing-example">X.509 certificate parsing example</a>,
Up: <a rel="up" accesskey="u" href="#Miscellaneous-examples">Miscellaneous examples</a>
</div>
<h4 class="subsection">7.5.1 Checking for an alert</h4>
<p>This is a function that checks if an alert has been received in the
current session.
<pre class="verbatim">
#include <stdio.h>
#include <stdlib.h>
#include <gnutls/gnutls.h>
/* 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 &&
ret == GNUTLS_E_WARNING_ALERT_RECEIVED)
printf ("* Received NO_RENEGOTIATION alert. "
"Client Does not support renegotiation.\n");
else
printf ("* Received alert '%d': %s.\n", last_alert,
gnutls_alert_get_name (last_alert));
}
}
</pre>
<div class="node">
<p><hr>
<a name="X.509-certificate-parsing-example"></a>
<a name="X_002e509-certificate-parsing-example"></a>
Next: <a rel="next" accesskey="n" href="#Certificate-request-generation">Certificate request generation</a>,
Previous: <a rel="previous" accesskey="p" href="#Checking-for-an-alert">Checking for an alert</a>,
Up: <a rel="up" accesskey="u" href="#Miscellaneous-examples">Miscellaneous examples</a>
</div>
<h4 class="subsection">7.5.2 <acronym>X.509</acronym> certificate parsing example</h4>
<p><a name="ex_003ax509_002dinfo"></a>
<p>To demonstrate the <acronym>X.509</acronym> parsing capabilities an example program is
listed below. That program reads the peer's certificate, and prints
information about it.
<pre class="verbatim">
#include <stdio.h>
#include <stdlib.h>
#include <gnutls/gnutls.h>
#include <gnutls/x509.h>
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 > 50)
bin_size = 50;
print = printable;
for (i = 0; i < bin_size; i++)
{
sprintf (print, "%.2x ", _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[128];
size_t size;
unsigned int algo, bits;
time_t expiration_time, activation_time;
const gnutls_datum_t *cert_list;
int cert_list_size = 0;
gnutls_x509_crt_t cert;
/* 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, &cert_list_size);
printf ("Peer provided %d certificates.\n", cert_list_size);
if (cert_list_size > 0)
{
/* we only print information about the first certificate.
*/
gnutls_x509_crt_init (&cert);
gnutls_x509_crt_import (cert, &cert_list[0], GNUTLS_X509_FMT_DER);
printf ("Certificate info:\n");
expiration_time = gnutls_x509_crt_get_expiration_time (cert);
activation_time = gnutls_x509_crt_get_activation_time (cert);
printf ("\tCertificate is valid since: %s", ctime (&activation_time));
printf ("\tCertificate expires: %s", ctime (&expiration_time));
/* Print the serial number of the certificate.
*/
size = sizeof (serial);
gnutls_x509_crt_get_serial (cert, serial, &size);
size = sizeof (serial);
printf ("\tCertificate serial number: %s\n", bin2hex (serial, size));
/* Extract some of the public key algorithm's parameters
*/
algo = gnutls_x509_crt_get_pk_algorithm (cert, &bits);
printf ("Certificate public key: %s",
gnutls_pk_algorithm_get_name (algo));
/* Print the version of the X.509
* certificate.
*/
printf ("\tCertificate version: #%d\n",
gnutls_x509_crt_get_version (cert));
size = sizeof (dn);
gnutls_x509_crt_get_dn (cert, dn, &size);
printf ("\tDN: %s\n", dn);
size = sizeof (dn);
gnutls_x509_crt_get_issuer_dn (cert, dn, &size);
printf ("\tIssuer's DN: %s\n", dn);
gnutls_x509_crt_deinit (cert);
}
}
</pre>
<div class="node">
<p><hr>
<a name="Certificate-request-generation"></a>
Next: <a rel="next" accesskey="n" href="#PKCS-_002312-structure-generation">PKCS #12 structure generation</a>,
Previous: <a rel="previous" accesskey="p" href="#X_002e509-certificate-parsing-example">X.509 certificate parsing example</a>,
Up: <a rel="up" accesskey="u" href="#Miscellaneous-examples">Miscellaneous examples</a>
</div>
<h4 class="subsection">7.5.3 Certificate request generation</h4>
<p><a name="ex_003acrq"></a>
<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.
<pre class="verbatim">
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <gnutls/gnutls.h>
#include <gnutls/x509.h>
#include <time.h>
/* 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];
int buffer_size = sizeof (buffer);
gnutls_global_init ();
/* Initialize an empty certificate request, and
* an empty private key.
*/
gnutls_x509_crq_init (&crq);
gnutls_x509_privkey_init (&key);
/* Generate a 1024 bit RSA private key.
*/
gnutls_x509_privkey_generate (key, GNUTLS_PK_RSA, 1024, 0);
/* Add stuff to the distinguished name
*/
gnutls_x509_crq_set_dn_by_oid (crq, GNUTLS_OID_X520_COUNTRY_NAME,
0, "GR", 2);
gnutls_x509_crq_set_dn_by_oid (crq, GNUTLS_OID_X520_COMMON_NAME,
0, "Nikos", strlen ("Nikos"));
/* Set the request version.
*/
gnutls_x509_crq_set_version (crq, 1);
/* Set a challenge password.
*/
gnutls_x509_crq_set_challenge_password (crq, "something to remember here");
/* Associate the request with the private key
*/
gnutls_x509_crq_set_key (crq, key);
/* Self sign the certificate request.
*/
gnutls_x509_crq_sign (crq, key);
/* Export the PEM encoded certificate request, and
* display it.
*/
gnutls_x509_crq_export (crq, GNUTLS_X509_FMT_PEM, buffer, &buffer_size);
printf ("Certificate Request: \n%s", buffer);
/* Export the PEM encoded private key, and
* display it.
*/
buffer_size = sizeof (buffer);
gnutls_x509_privkey_export (key, GNUTLS_X509_FMT_PEM, buffer, &buffer_size);
printf ("\n\nPrivate key: \n%s", buffer);
gnutls_x509_crq_deinit (crq);
gnutls_x509_privkey_deinit (key);
return 0;
}
</pre>
<div class="node">
<p><hr>
<a name="PKCS-%2312-structure-generation"></a>
<a name="PKCS-_002312-structure-generation"></a>
Previous: <a rel="previous" accesskey="p" href="#Certificate-request-generation">Certificate request generation</a>,
Up: <a rel="up" accesskey="u" href="#Miscellaneous-examples">Miscellaneous examples</a>
</div>
<h4 class="subsection">7.5.4 <acronym>PKCS</acronym> #12 structure generation</h4>
<p><a name="ex_003apkcs12"></a>
<p>The following example is about generating a <acronym>PKCS</acronym> #12
structure.
<pre class="verbatim">
#include <stdio.h>
#include <stdlib.h>
#include <gnutls/gnutls.h>
#include <gnutls/pkcs12.h>
#define OUTFILE "out.p12"
/* 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];
int pkcs12_struct_size;
FILE *fd;
/* A good idea might be to use gnutls_x509_privkey_get_key_id()
* to obtain a unique ID.
*/
gnutls_datum_t key_id = { "\x00\x00\x07", 3 };
gnutls_global_init ();
/* Firstly we create two helper bags, which hold the certificate,
* and the (encrypted) key.
*/
gnutls_pkcs12_bag_init (&bag);
gnutls_pkcs12_bag_init (&key_bag);
ret = gnutls_pkcs12_bag_set_data (bag, GNUTLS_BAG_CERTIFICATE, cert);
if (ret < 0)
{
fprintf (stderr, "ret: %s\n", 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, "My name");
/* Associate the certificate with the key using a unique key
* ID.
*/
gnutls_pkcs12_bag_set_key_id (bag, bag_index, &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 < 0)
{
fprintf (stderr, "ret: %s\n", 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, "My name");
gnutls_pkcs12_bag_set_key_id (key_bag, bag_index, &key_id);
/* The bags were filled. Now create the PKCS #12 structure.
*/
gnutls_pkcs12_init (&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,
&pkcs12_struct_size);
if (ret < 0)
{
fprintf (stderr, "ret: %s\n", gnutls_strerror (ret));
return 1;
}
fd = fopen (OUTFILE, "w");
if (fd == NULL)
{
fprintf (stderr, "cannot open file\n");
return 1;
}
fwrite (pkcs12_struct, 1, pkcs12_struct_size, fd);
fclose (fd);
gnutls_pkcs12_bag_deinit (bag);
gnutls_pkcs12_bag_deinit (key_bag);
gnutls_pkcs12_deinit (pkcs12);
return 0;
}
</pre>
<div class="node">
<p><hr>
<a name="Compatibility-with-the-OpenSSL-library"></a>
Previous: <a rel="previous" accesskey="p" href="#Miscellaneous-examples">Miscellaneous examples</a>,
Up: <a rel="up" accesskey="u" href="#How-to-use-GnuTLS-in-applications">How to use GnuTLS in applications</a>
</div>
<h3 class="section">7.6 Compatibility with the OpenSSL library</h3>
<p><a name="index-OpenSSL-34"></a>
To ease <acronym>GnuTLS</acronym>' integration with existing applications, a
compatibility layer with the widely used OpenSSL library is included
in the <code>gnutls-openssl</code> library. This compatibility layer is not
complete and it is not intended to completely reimplement the OpenSSL
API with <acronym>GnuTLS</acronym>. It only provides source-level
compatibility. There is currently no attempt to make it
binary-compatible with OpenSSL.
<p>The prototypes for the compatibility functions are in the
<samp><span class="file">gnutls/openssl.h</span></samp> header file.
<p>Current limitations imposed by the compatibility layer include:
<ul>
<li>Error handling is not thread safe.
</ul>
<div class="node">
<p><hr>
<a name="Included-programs"></a>
Next: <a rel="next" accesskey="n" href="#Function-reference">Function reference</a>,
Previous: <a rel="previous" accesskey="p" href="#How-to-use-GnuTLS-in-applications">How to use GnuTLS in applications</a>,
Up: <a rel="up" accesskey="u" href="#Top">Top</a>
</div>
<h2 class="chapter">8 Included programs</h2>
<p>Included with <acronym>GnuTLS</acronym> 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.
<ul class="menu">
<li><a accesskey="1" href="#Invoking-srptool">Invoking srptool</a>
<li><a accesskey="2" href="#Invoking-gnutls_002dcli">Invoking gnutls-cli</a>
<li><a accesskey="3" href="#Invoking-gnutls_002dcli_002ddebug">Invoking gnutls-cli-debug</a>
<li><a accesskey="4" href="#Invoking-gnutls_002dserv">Invoking gnutls-serv</a>
<li><a accesskey="5" href="#Invoking-certtool">Invoking certtool</a>
</ul>
<div class="node">
<p><hr>
<a name="Invoking-srptool"></a>
Next: <a rel="next" accesskey="n" href="#Invoking-gnutls_002dcli">Invoking gnutls-cli</a>,
Up: <a rel="up" accesskey="u" href="#Included-programs">Included programs</a>
</div>
<h3 class="section">8.1 Invoking srptool</h3>
<p><a name="srptool"></a>
<a name="index-srptool-35"></a>
The <samp><span class="file">srptool</span></samp> is a very simple program that emulates the programs
in the <em>Stanford SRP libraries</em>. It is intended for use in
places where you don't expect <acronym>SRP</acronym> authentication to be the
used for system users. Traditionally <em>libsrp</em> used two
files. One called 'tpasswd' which holds usernames and verifiers, and
'tpasswd.conf' which holds generators and primes.
<p>How to use srptool:
<ul>
<li>To create tpasswd.conf which holds the g and n values for
<acronym>SRP</acronym> protocol (generator and a large prime), run:
<pre class="example"> $ srptool --create-conf /etc/tpasswd.conf
</pre>
<li>This command will create /etc/tpasswd and will add user 'test' (you
will also be prompted for a password). Verifiers are stored by default
in the way libsrp expects.
<pre class="example"> $ srptool --passwd /etc/tpasswd \
--passwd-conf /etc/tpasswd.conf -u test
</pre>
<li>This command will check against a password. If the password matches
the one in /etc/tpasswd you will get an ok.
<pre class="example"> $ srptool --passwd /etc/tpasswd \
--passwd-conf /etc/tpasswd.conf --verify -u test
</pre>
</ul>
<div class="node">
<p><hr>
<a name="Invoking-gnutls-cli"></a>
<a name="Invoking-gnutls_002dcli"></a>
Next: <a rel="next" accesskey="n" href="#Invoking-gnutls_002dcli_002ddebug">Invoking gnutls-cli-debug</a>,
Previous: <a rel="previous" accesskey="p" href="#Invoking-srptool">Invoking srptool</a>,
Up: <a rel="up" accesskey="u" href="#Included-programs">Included programs</a>
</div>
<h3 class="section">8.2 Invoking gnutls-cli</h3>
<p><a name="index-gnutls_002dcli-36"></a>
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.
<pre class="verbatim">
GNU TLS test client
Usage: gnutls-cli [options] hostname
-d, --debug integer Enable debugging
-r, --resume Connect, establish a session. Connect
again and resume this session.
-s, --starttls Connect, establish a plain session and
start TLS when EOF or a SIGALRM is
received.
--crlf Send CR LF instead of LF.
--x509fmtder Use DER format for certificates to read
from.
-f, --fingerprint Send the openpgp fingerprint, instead
of the key.
--disable-extensions Disable all the TLS extensions.
--xml Print the certificate information in
XML format.
--print-cert Print the certificate in PEM format.
-p, --port integer The port to connect to.
--recordsize integer The maximum record size to advertize.
-V, --verbose More verbose output.
--ciphers cipher1 cipher2...
Ciphers to enable.
--protocols protocol1 protocol2...
Protocols to enable.
--comp comp1 comp2... Compression methods to enable.
--macs mac1 mac2... MACs to enable.
--kx kx1 kx2... Key exchange methods to enable.
--ctypes certType1 certType2...
Certificate types to enable.
--x509cafile FILE Certificate file to use.
--x509crlfile FILE CRL file to use.
--pgpkeyfile FILE PGP Key file to use.
--pgpkeyring FILE PGP Key ring file to use.
--pgptrustdb FILE PGP trustdb file to use.
--pgpcertfile FILE PGP Public Key (certificate) file to
use.
--x509keyfile FILE X.509 key file to use.
--x509certfile FILE X.509 Certificate file to use.
--srpusername NAME SRP username to use.
--srppasswd PASSWD SRP password to use.
--insecure Don't abort program if server
certificate can't be validated.
-l, --list Print a list of the supported
algorithms and modes.
-h, --help prints this help
-v, --version prints the program's version number
--copyright prints the program's license
</pre>
<div class="node">
<p><hr>
<a name="Invoking-gnutls-cli-debug"></a>
<a name="Invoking-gnutls_002dcli_002ddebug"></a>
Next: <a rel="next" accesskey="n" href="#Invoking-gnutls_002dserv">Invoking gnutls-serv</a>,
Previous: <a rel="previous" accesskey="p" href="#Invoking-gnutls_002dcli">Invoking gnutls-cli</a>,
Up: <a rel="up" accesskey="u" href="#Included-programs">Included programs</a>
</div>
<h3 class="section">8.3 Invoking gnutls-cli-debug</h3>
<p><a name="index-gnutls_002dcli_002ddebug-37"></a>
This program was created to assist in debugging <acronym>GnuTLS</acronym>, but
it might be useful to extract a <acronym>TLS</acronym> server's capabilities.
It's purpose is to connect onto a <acronym>TLS</acronym> server, perform some
tests and print the server's capabilities. If called with the `-v'
parameter a more checks will be performed. An example output is:
<pre class="smallexample"> crystal:/cvs/gnutls/src$ ./gnutls-cli-debug localhost -p 5556
Resolving 'localhost'...
Connecting to '127.0.0.1:5556'...
Checking for TLS 1.1 support... yes
Checking fallback from TLS 1.1 to... N/A
Checking for TLS 1.0 support... yes
Checking for SSL 3.0 support... yes
Checking for version rollback bug in RSA PMS... no
Checking for version rollback bug in Client Hello... no
Checking whether we need to disable TLS 1.0... N/A
Checking whether the server ignores the RSA PMS version... no
Checking whether the server can accept Hello Extensions... yes
Checking whether the server can accept cipher suites not in SSL 3.0 spec... yes
Checking whether the server can accept a bogus TLS record version in the client hello... yes
Checking for certificate information... N/A
Checking for trusted CAs... N/A
Checking whether the server understands TLS closure alerts... yes
Checking whether the server supports session resumption... yes
Checking for export-grade ciphersuite support... no
Checking RSA-export ciphersuite info... N/A
Checking for anonymous authentication support... no
Checking anonymous Diffie Hellman group info... N/A
Checking for ephemeral Diffie Hellman support... no
Checking ephemeral Diffie Hellman group info... N/A
Checking for AES cipher support (TLS extension)... yes
Checking for 3DES cipher support... yes
Checking for ARCFOUR 128 cipher support... yes
Checking for ARCFOUR 40 cipher support... no
Checking for MD5 MAC support... yes
Checking for SHA1 MAC support... yes
Checking for ZLIB compression support (TLS extension)... yes
Checking for LZO compression support (GnuTLS extension)... yes
Checking for max record size (TLS extension)... yes
Checking for SRP authentication support (TLS extension)... yes
Checking for OpenPGP authentication support (TLS extension)... no
</pre>
<div class="node">
<p><hr>
<a name="Invoking-gnutls-serv"></a>
<a name="Invoking-gnutls_002dserv"></a>
Next: <a rel="next" accesskey="n" href="#Invoking-certtool">Invoking certtool</a>,
Previous: <a rel="previous" accesskey="p" href="#Invoking-gnutls_002dcli_002ddebug">Invoking gnutls-cli-debug</a>,
Up: <a rel="up" accesskey="u" href="#Included-programs">Included programs</a>
</div>
<h3 class="section">8.4 Invoking gnutls-serv</h3>
<p><a name="index-gnutls_002dserv-38"></a>
Simple server program that listens to incoming TLS connections.
<pre class="verbatim">
GNU TLS test server
Usage: gnutls-serv [options]
-d, --debug integer Enable debugging
-g, --generate Generate Diffie Hellman Parameters.
-p, --port integer The port to connect to.
-q, --quiet Suppress some messages.
--nodb Does not use the resume database.
--http Act as an HTTP Server.
--echo Act as an Echo Server.
--dhparams FILE DH params file to use.
--x509fmtder Use DER format for certificates
--x509cafile FILE Certificate file to use.
--x509crlfile FILE CRL file to use.
--pgpkeyring FILE PGP Key ring file to use.
--pgptrustdb FILE PGP trustdb file to use.
--pgpkeyfile FILE PGP Key file to use.
--pgpcertfile FILE PGP Public Key (certificate) file to
use.
--x509keyfile FILE X.509 key file to use.
--x509certfile FILE X.509 Certificate file to use.
--x509dsakeyfile FILE Alternative X.509 key file to use.
--x509dsacertfile FILE Alternative X.509 certificate file to
use.
--srppasswd FILE SRP password file to use.
--srppasswdconf FILE SRP password conf file to use.
--ciphers cipher1 cipher2...
Ciphers to enable.
--protocols protocol1 protocol2...
Protocols to enable.
--comp comp1 comp2... Compression methods to enable.
--macs mac1 mac2... MACs to enable.
--kx kx1 kx2... Key exchange methods to enable.
--ctypes certType1 certType2...
Certificate types to enable.
-l, --list Print a list of the supported
algorithms and modes.
-h, --help prints this help
-v, --version prints the program's version number
--copyright prints the program's license
</pre>
<div class="node">
<p><hr>
<a name="Invoking-certtool"></a>
Previous: <a rel="previous" accesskey="p" href="#Invoking-gnutls_002dserv">Invoking gnutls-serv</a>,
Up: <a rel="up" accesskey="u" href="#Included-programs">Included programs</a>
</div>
<h3 class="section">8.5 Invoking certtool</h3>
<p><a name="index-certtool-39"></a>
This is a program to generate <acronym>X.509</acronym> certificates, certificate
requests, CRLs and private keys. The program can be used interactively
or non interactively by specifying the <code>--template</code> command line
option. See below for an example of a template file.
<p>How to use certtool interactively:
<ul>
<li>To generate parameters for Diffie Hellman key exchange, use the command:
<pre class="example"> $ certtool --generate-dh-params --outfile dh.pem
</pre>
<li>To generate parameters for the RSA-EXPORT key exchange, use the command:
<pre class="example"> $ certtool --generate-privkey --bits 512 --outfile rsa.pem
</pre>
</ul>
<ul>
<li>To create a self signed certificate, use the command:
<pre class="example"> $ certtool --generate-privkey --outfile ca-key.pem
$ certtool --generate-self-signed --load-privkey ca-key.pem \
--outfile ca-cert.pem
</pre>
<p>Note that a self-signed certificate usually belongs to a certificate
authority, that signs other certificates.
<li>To create a private key, run:
<pre class="example"> $ certtool --generate-privkey --outfile key.pem
</pre>
<li>To create a certificate request, run:
<pre class="example"> $ certtool --generate-request --load-privkey key.pem \
--outfile request.pem
</pre>
<li>To generate a certificate using the previous request, use the command:
<pre class="example"> $ certtool --generate-certificate --load-request request.pem \
--outfile cert.pem \
--load-ca-certificate ca-cert.pem --load-ca-privkey ca-key.pem
</pre>
<li>To view the certificate information, use:
<pre class="example"> $ certtool --certificate-info --infile cert.pem
</pre>
<li>To generate a <acronym>PKCS</acronym> #12 structure using the previous key and
certificate, use the command:
<pre class="example"> $ certtool --load-certificate cert.pem --load-privkey key.pem \
--to-p12 --outder --outfile key.p12
</pre>
</ul>
<p>Certtool's template file format:
<ul>
<li>Firstly create a file named 'cert.cfg' that contains the information
about the certificate. An example file is listed below.
<li>Then execute:
<pre class="example"> $ certtool --generate-certificate cert.pem --load-privkey key.pem \
--template cert.cfg \
--load-ca-certificate ca-cert.pem --load-ca-privkey ca-key.pem
</pre>
</ul>
<p>An example certtool template file:
<pre class="example"> # X.509 Certificate options
#
# DN options
# The organization of the subject.
organization = "Koko inc."
# The organizational unit of the subject.
unit = "sleeping dept."
# The locality of the subject.
# locality =
# The state of the certificate owner.
state = "Attiki"
# The country of the subject. Two letter code.
country = GR
# The common name of the certificate owner.
cn = "Cindy Lauper"
# A user id of the certificate owner.
#uid = "clauper"
# 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 = "2.5.4.12" "Dr." "2.5.4.65" "jackal"
# This is deprecated and should not be used in new
# certificates.
# pkcs9_email = "none@none.org"
# The serial number of the certificate
serial = 007
# In how many days, counting from today, this certificate will expire.
expiration_days = 700
# X.509 v3 extensions
# A dnsname in case of a WWW server.
#dns_name = "www.none.org"
# An IP address in case of a server.
#ip_address = "192.168.1.1"
# An email in case of a person
email = "none@none.org"
# An URL that has CRLs (certificate revocation lists)
# available. Needed in CA certificates.
#crl_dist_points = "http://www.getcrl.crl/getcrl/"
# Whether this is a CA certificate or not
#ca
# Whether this certificate will be used for a TLS client
#tls_www_client
# Whether this certificate will be used for a TLS server
#tls_www_server
# Whether this certificate will be used to sign data (needed
# in TLS DHE ciphersuites).
signing_key
# Whether this certificate will be used to encrypt data (needed
# in TLS RSA ciphersuites). Note that it is prefered to use different
# keys for encryption and signing.
#encryption_key
# Whether this key will be used to sign other certificates.
#cert_signing_key
# Whether this key will be used to sign CRLs.
#crl_signing_key
# Whether this key will be used to sign code.
#code_signing_key
# Whether this key will be used to sign OCSP data.
#ocsp_signing_key
# Whether this key will be used for time stamping.
#time_stamping_key
</pre>
<div class="node">
<p><hr>
<a name="Function-reference"></a>
Next: <a rel="next" accesskey="n" href="#Certificate-to-XML-convertion-functions">Certificate to XML convertion functions</a>,
Previous: <a rel="previous" accesskey="p" href="#Included-programs">Included programs</a>,
Up: <a rel="up" accesskey="u" href="#Top">Top</a>
</div>
<h2 class="chapter">9 Function reference</h2>
<p><a name="index-Function-reference-40"></a>
<ul class="menu">
<li><a accesskey="1" href="#Core-functions">Core functions</a>
<li><a accesskey="2" href="#X_002e509-certificate-functions">X.509 certificate functions</a>
<li><a accesskey="3" href="#GnuTLS_002dextra-functions">GnuTLS-extra functions</a>
<li><a accesskey="4" href="#OpenPGP-functions">OpenPGP functions</a>
<li><a accesskey="5" href="#TLS-Inner-Application-_0028TLS_002fIA_0029-functions">TLS Inner Application (TLS/IA) functions</a>
<li><a accesskey="6" href="#Error-codes-and-descriptions">Error codes and descriptions</a>
</ul>
<div class="node">
<p><hr>
<a name="Core-functions"></a>
Next: <a rel="next" accesskey="n" href="#X_002e509-certificate-functions">X.509 certificate functions</a>,
Up: <a rel="up" accesskey="u" href="#Function-reference">Function reference</a>
</div>
<h3 class="section">9.1 Core functions</h3>
<p>The prototypes for the following functions lie in
<samp><span class="file">gnutls/gnutls.h</span></samp>.
<h4 class="subheading">gnutls_alert_get_name</h4>
<p><a name="gnutls_005falert_005fget_005fname"></a>
<div class="defun">
— Function: const char * <b>gnutls_alert_get_name</b> (<var>gnutls_alert_description_t alert</var>)<var><a name="index-gnutls_005falert_005fget_005fname-41"></a></var><br>
<blockquote><p><var>alert</var>: is an alert number <code>gnutls_session_t</code> structure.
<p>This function will return a string that describes the given alert
number or NULL. See <code>gnutls_alert_get()</code>.
</p></blockquote></div>
<h4 class="subheading">gnutls_alert_get</h4>
<p><a name="gnutls_005falert_005fget"></a>
<div class="defun">
— Function: gnutls_alert_description_t <b>gnutls_alert_get</b> (<var>gnutls_session_t session</var>)<var><a name="index-gnutls_005falert_005fget-42"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p>This function will return the last alert number received. This
function should be called if GNUTLS_E_WARNING_ALERT_RECEIVED or
GNUTLS_E_FATAL_ALERT_RECEIVED has been returned by a gnutls
function. The peer may send alerts if he thinks some things were
not right. Check gnutls.h for the available alert descriptions.
<p>If no alert has been received the returned value is undefined.
</p></blockquote></div>
<h4 class="subheading">gnutls_alert_send_appropriate</h4>
<p><a name="gnutls_005falert_005fsend_005fappropriate"></a>
<div class="defun">
— Function: int <b>gnutls_alert_send_appropriate</b> (<var>gnutls_session_t session, int err</var>)<var><a name="index-gnutls_005falert_005fsend_005fappropriate-43"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p><var>err</var>: is an integer
<p>Sends an alert to the peer depending on the error code returned by a gnutls
function. This function will call <code>gnutls_error_to_alert()</code> to determine
the appropriate alert to send.
<p>This function may also return GNUTLS_E_AGAIN, or GNUTLS_E_INTERRUPTED.
<p>If the return value is GNUTLS_E_INVALID_REQUEST, then no alert has
been sent to the peer.
<p>Returns zero on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_alert_send</h4>
<p><a name="gnutls_005falert_005fsend"></a>
<div class="defun">
— Function: int <b>gnutls_alert_send</b> (<var>gnutls_session_t session, gnutls_alert_level_t level, gnutls_alert_description_t desc</var>)<var><a name="index-gnutls_005falert_005fsend-44"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p><var>level</var>: is the level of the alert
<p><var>desc</var>: is the alert description
<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>The error code of the underlying record send function will be returned,
so you may also receive GNUTLS_E_INTERRUPTED or GNUTLS_E_AGAIN as well.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_anon_allocate_client_credentials</h4>
<p><a name="gnutls_005fanon_005fallocate_005fclient_005fcredentials"></a>
<div class="defun">
— Function: int <b>gnutls_anon_allocate_client_credentials</b> (<var>gnutls_anon_client_credentials_t * sc</var>)<var><a name="index-gnutls_005fanon_005fallocate_005fclient_005fcredentials-45"></a></var><br>
<blockquote><p><var>sc</var>: is a pointer to an <code>gnutls_anon_client_credentials_t</code> structure.
<p>This structure is complex enough to manipulate directly thus
this helper function is provided in order to allocate it.
<p>Returns a negative value in case of an error.
</p></blockquote></div>
<h4 class="subheading">gnutls_anon_allocate_server_credentials</h4>
<p><a name="gnutls_005fanon_005fallocate_005fserver_005fcredentials"></a>
<div class="defun">
— Function: int <b>gnutls_anon_allocate_server_credentials</b> (<var>gnutls_anon_server_credentials_t * sc</var>)<var><a name="index-gnutls_005fanon_005fallocate_005fserver_005fcredentials-46"></a></var><br>
<blockquote><p><var>sc</var>: is a pointer to an <code>gnutls_anon_server_credentials_t</code> structure.
<p>This structure is complex enough to manipulate directly thus
this helper function is provided in order to allocate it.
<p>Returns a negative value in case of an error.
</p></blockquote></div>
<h4 class="subheading">gnutls_anon_free_client_credentials</h4>
<p><a name="gnutls_005fanon_005ffree_005fclient_005fcredentials"></a>
<div class="defun">
— Function: void <b>gnutls_anon_free_client_credentials</b> (<var>gnutls_anon_client_credentials_t sc</var>)<var><a name="index-gnutls_005fanon_005ffree_005fclient_005fcredentials-47"></a></var><br>
<blockquote><p><var>sc</var>: is an <code>gnutls_anon_client_credentials_t</code> structure.
<p>This structure is complex enough to manipulate directly thus
this helper function is provided in order to free (deallocate) it.
</p></blockquote></div>
<h4 class="subheading">gnutls_anon_free_server_credentials</h4>
<p><a name="gnutls_005fanon_005ffree_005fserver_005fcredentials"></a>
<div class="defun">
— Function: void <b>gnutls_anon_free_server_credentials</b> (<var>gnutls_anon_server_credentials_t sc</var>)<var><a name="index-gnutls_005fanon_005ffree_005fserver_005fcredentials-48"></a></var><br>
<blockquote><p><var>sc</var>: is an <code>gnutls_anon_server_credentials_t</code> structure.
<p>This structure is complex enough to manipulate directly thus
this helper function is provided in order to free (deallocate) it.
</p></blockquote></div>
<h4 class="subheading">gnutls_anon_set_params_function</h4>
<p><a name="gnutls_005fanon_005fset_005fparams_005ffunction"></a>
<div class="defun">
— Function: void <b>gnutls_anon_set_params_function</b> (<var>gnutls_anon_server_credentials_t res, gnutls_params_function * func</var>)<var><a name="index-gnutls_005fanon_005fset_005fparams_005ffunction-49"></a></var><br>
<blockquote><p><var>res</var>: is a gnutls_anon_server_credentials_t structure
<p><var>func</var>: is the function to be called
<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 zero on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_anon_set_server_dh_params</h4>
<p><a name="gnutls_005fanon_005fset_005fserver_005fdh_005fparams"></a>
<div class="defun">
— Function: void <b>gnutls_anon_set_server_dh_params</b> (<var>gnutls_anon_server_credentials_t res, gnutls_dh_params_t dh_params</var>)<var><a name="index-gnutls_005fanon_005fset_005fserver_005fdh_005fparams-50"></a></var><br>
<blockquote><p><var>res</var>: is a gnutls_anon_server_credentials_t structure
<p><var>dh_params</var>: is a structure that holds diffie hellman parameters.
<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></blockquote></div>
<h4 class="subheading">gnutls_anon_set_server_params_function</h4>
<p><a name="gnutls_005fanon_005fset_005fserver_005fparams_005ffunction"></a>
<div class="defun">
— Function: void <b>gnutls_anon_set_server_params_function</b> (<var>gnutls_anon_server_credentials_t res, gnutls_params_function * func</var>)<var><a name="index-gnutls_005fanon_005fset_005fserver_005fparams_005ffunction-51"></a></var><br>
<blockquote><p><var>res</var>: is a gnutls_certificate_credentials_t structure
<p><var>func</var>: is the function to be called
<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 zero on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_auth_client_get_type</h4>
<p><a name="gnutls_005fauth_005fclient_005fget_005ftype"></a>
<div class="defun">
— Function: gnutls_credentials_type_t <b>gnutls_auth_client_get_type</b> (<var>gnutls_session_t session</var>)<var><a name="index-gnutls_005fauth_005fclient_005fget_005ftype-52"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<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></blockquote></div>
<h4 class="subheading">gnutls_auth_get_type</h4>
<p><a name="gnutls_005fauth_005fget_005ftype"></a>
<div class="defun">
— Function: gnutls_credentials_type_t <b>gnutls_auth_get_type</b> (<var>gnutls_session_t session</var>)<var><a name="index-gnutls_005fauth_005fget_005ftype-53"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<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>Eg. for CERTIFICATE ciphersuites (key exchange algorithms: KX_RSA, KX_DHE_RSA),
the same function are to be used to access the authentication data.
</p></blockquote></div>
<h4 class="subheading">gnutls_auth_server_get_type</h4>
<p><a name="gnutls_005fauth_005fserver_005fget_005ftype"></a>
<div class="defun">
— Function: gnutls_credentials_type_t <b>gnutls_auth_server_get_type</b> (<var>gnutls_session_t session</var>)<var><a name="index-gnutls_005fauth_005fserver_005fget_005ftype-54"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<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></blockquote></div>
<h4 class="subheading">gnutls_bye</h4>
<p><a name="gnutls_005fbye"></a>
<div class="defun">
— Function: int <b>gnutls_bye</b> (<var>gnutls_session_t session, gnutls_close_request_t how</var>)<var><a name="index-gnutls_005fbye-55"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p><var>how</var>: is an integer
<p>Terminates the current TLS/SSL connection. The connection should
have been initiated using <code>gnutls_handshake()</code>.
<code>how</code> should be one of GNUTLS_SHUT_RDWR, GNUTLS_SHUT_WR.
<p>In case of GNUTLS_SHUT_RDWR then the TLS connection gets terminated and
further receives and sends will be disallowed. If the return
value is zero you may continue using the connection.
GNUTLS_SHUT_RDWR actually sends an alert containing a close request
and waits for the peer to reply with the same message.
<p>In case of GNUTLS_SHUT_WR then the TLS connection gets terminated and
further sends will be disallowed. In order to reuse the connection
you should wait for an EOF from the peer.
GNUTLS_SHUT_WR sends an alert containing a close request.
<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, thus causing a transmission error to the peer.
This error cannot be distinguished from a malicious party prematurely terminating
the session, thus this behavior is not recommended.
<p>This function may also return GNUTLS_E_AGAIN or GNUTLS_E_INTERRUPTED; cf.
<code>gnutls_record_get_direction()</code>.
</p></blockquote></div>
<h4 class="subheading">gnutls_certificate_activation_time_peers</h4>
<p><a name="gnutls_005fcertificate_005factivation_005ftime_005fpeers"></a>
<div class="defun">
— Function: time_t <b>gnutls_certificate_activation_time_peers</b> (<var>gnutls_session_t session</var>)<var><a name="index-gnutls_005fcertificate_005factivation_005ftime_005fpeers-56"></a></var><br>
<blockquote><p><var>session</var>: is a gnutls session
<p>This function will return the peer's certificate activation time.
This is the creation time for openpgp keys.
<p>Returns (time_t) -1 on error.
</p></blockquote></div>
<h4 class="subheading">gnutls_certificate_allocate_credentials</h4>
<p><a name="gnutls_005fcertificate_005fallocate_005fcredentials"></a>
<div class="defun">
— Function: int <b>gnutls_certificate_allocate_credentials</b> (<var>gnutls_certificate_credentials_t * res</var>)<var><a name="index-gnutls_005fcertificate_005fallocate_005fcredentials-57"></a></var><br>
<blockquote><p><var>res</var>: is a pointer to an <code>gnutls_certificate_credentials_t</code> structure.
<p>This structure is complex enough to manipulate directly thus
this helper function is provided in order to allocate it.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_certificate_client_get_request_status</h4>
<p><a name="gnutls_005fcertificate_005fclient_005fget_005frequest_005fstatus"></a>
<div class="defun">
— Function: int <b>gnutls_certificate_client_get_request_status</b> (<var>gnutls_session_t session</var>)<var><a name="index-gnutls_005fcertificate_005fclient_005fget_005frequest_005fstatus-58"></a></var><br>
<blockquote><p><var>session</var>: is a gnutls session
<p>This function will return 0 if the peer (server) did not request client
authentication or 1 otherwise.
Returns a negative value in case of an error.
</p></blockquote></div>
<h4 class="subheading">gnutls_certificate_client_set_retrieve_function</h4>
<p><a name="gnutls_005fcertificate_005fclient_005fset_005fretrieve_005ffunction"></a>
<div class="defun">
— Function: void <b>gnutls_certificate_client_set_retrieve_function</b> (<var>gnutls_certificate_credentials_t cred, gnutls_certificate_client_retrieve_function * func</var>)<var><a name="index-gnutls_005fcertificate_005fclient_005fset_005fretrieve_005ffunction-59"></a></var><br>
<blockquote><p><var>cred</var>: is a <code>gnutls_certificate_credentials_t</code> structure.
<p><var>func</var>: is the callback function
<p>This function sets a callback to be called in order to retrieve the certificate
to be used in the handshake.
The callback's function prototype is:
int (*callback)(gnutls_session_t, const gnutls_datum_t* req_ca_dn, int nreqs,
gnutls_pk_algorithm_t* pk_algos, int pk_algos_length, gnutls_retr_st* st);
<p><code>st</code> should contain the certificates and private keys.
<p><code>req_ca_cert</code>, is only used in X.509 certificates.
Contains a list with the CA names that the server considers trusted.
Normally we should send a certificate that is signed
by one of these CAs. These names are DER encoded. To get a more
meaningful value use the function <code>gnutls_x509_rdn_get()</code>.
<p><code>pk_algos</code>, contains a list with server's acceptable signature algorithms.
The certificate returned should support the server's given algorithms.
<p>If the callback function is provided then gnutls will call it, in the
handshake, after the certificate request message has been received.
<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.
</p></blockquote></div>
<h4 class="subheading">gnutls_certificate_expiration_time_peers</h4>
<p><a name="gnutls_005fcertificate_005fexpiration_005ftime_005fpeers"></a>
<div class="defun">
— Function: time_t <b>gnutls_certificate_expiration_time_peers</b> (<var>gnutls_session_t session</var>)<var><a name="index-gnutls_005fcertificate_005fexpiration_005ftime_005fpeers-60"></a></var><br>
<blockquote><p><var>session</var>: is a gnutls session
<p>This function will return the peer's certificate expiration time.
<p>Returns (time_t) -1 on error.
</p></blockquote></div>
<h4 class="subheading">gnutls_certificate_free_ca_names</h4>
<p><a name="gnutls_005fcertificate_005ffree_005fca_005fnames"></a>
<div class="defun">
— Function: void <b>gnutls_certificate_free_ca_names</b> (<var>gnutls_certificate_credentials_t sc</var>)<var><a name="index-gnutls_005fcertificate_005ffree_005fca_005fnames-61"></a></var><br>
<blockquote><p><var>sc</var>: is an <code>gnutls_certificate_credentials_t</code> structure.
<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.
<p>CA names are used by servers to advertize the CAs they
support to clients.
</p></blockquote></div>
<h4 class="subheading">gnutls_certificate_free_cas</h4>
<p><a name="gnutls_005fcertificate_005ffree_005fcas"></a>
<div class="defun">
— Function: void <b>gnutls_certificate_free_cas</b> (<var>gnutls_certificate_credentials_t sc</var>)<var><a name="index-gnutls_005fcertificate_005ffree_005fcas-62"></a></var><br>
<blockquote><p><var>sc</var>: is an <code>gnutls_certificate_credentials_t</code> structure.
<p>This function will delete all the CAs associated
with the given credentials. Servers that do not use
<code>gnutls_certificate_verify_peers2()</code> may call this to
save some memory.
</p></blockquote></div>
<h4 class="subheading">gnutls_certificate_free_credentials</h4>
<p><a name="gnutls_005fcertificate_005ffree_005fcredentials"></a>
<div class="defun">
— Function: void <b>gnutls_certificate_free_credentials</b> (<var>gnutls_certificate_credentials_t sc</var>)<var><a name="index-gnutls_005fcertificate_005ffree_005fcredentials-63"></a></var><br>
<blockquote><p><var>sc</var>: is an <code>gnutls_certificate_credentials_t</code> structure.
<p>This structure is complex enough to manipulate directly thus
this helper function is provided in order to free (deallocate) it.
<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></blockquote></div>
<h4 class="subheading">gnutls_certificate_free_crls</h4>
<p><a name="gnutls_005fcertificate_005ffree_005fcrls"></a>
<div class="defun">
— Function: void <b>gnutls_certificate_free_crls</b> (<var>gnutls_certificate_credentials_t sc</var>)<var><a name="index-gnutls_005fcertificate_005ffree_005fcrls-64"></a></var><br>
<blockquote><p><var>sc</var>: is an <code>gnutls_certificate_credentials_t</code> structure.
<p>This function will delete all the CRLs associated
with the given credentials.
</p></blockquote></div>
<h4 class="subheading">gnutls_certificate_free_keys</h4>
<p><a name="gnutls_005fcertificate_005ffree_005fkeys"></a>
<div class="defun">
— Function: void <b>gnutls_certificate_free_keys</b> (<var>gnutls_certificate_credentials_t sc</var>)<var><a name="index-gnutls_005fcertificate_005ffree_005fkeys-65"></a></var><br>
<blockquote><p><var>sc</var>: is an <code>gnutls_certificate_credentials_t</code> structure.
<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></blockquote></div>
<h4 class="subheading">gnutls_certificate_get_ours</h4>
<p><a name="gnutls_005fcertificate_005fget_005fours"></a>
<div class="defun">
— Function: const gnutls_datum_t * <b>gnutls_certificate_get_ours</b> (<var>gnutls_session_t session</var>)<var><a name="index-gnutls_005fcertificate_005fget_005fours-66"></a></var><br>
<blockquote><p><var>session</var>: is a gnutls session
<p>This function will return the certificate as sent to the peer,
in the last handshake. These certificates are in raw format.
In X.509 this is a certificate list. In OpenPGP this is a single
certificate.
Returns NULL in case of an error, or if no certificate was used.
</p></blockquote></div>
<h4 class="subheading">gnutls_certificate_get_peers</h4>
<p><a name="gnutls_005fcertificate_005fget_005fpeers"></a>
<div class="defun">
— Function: const gnutls_datum_t * <b>gnutls_certificate_get_peers</b> (<var>gnutls_session_t session, unsigned int * list_size</var>)<var><a name="index-gnutls_005fcertificate_005fget_005fpeers-67"></a></var><br>
<blockquote><p><var>session</var>: is a gnutls session
<p><var>list_size</var>: is the length of the certificate list
<p>This function will return the peer'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 first certificate in the list is the peer's certificate,
following the issuer's certificate, then the issuer's issuer etc.
<p>In case of OpenPGP keys a single key will be returned
in raw format.
<p>Returns NULL in case of an error, or if no certificate was sent.
</p></blockquote></div>
<h4 class="subheading">gnutls_certificate_send_x509_rdn_sequence</h4>
<p><a name="gnutls_005fcertificate_005fsend_005fx509_005frdn_005fsequence"></a>
<div class="defun">
— Function: void <b>gnutls_certificate_send_x509_rdn_sequence</b> (<var>gnutls_session_t session, int status</var>)<var><a name="index-gnutls_005fcertificate_005fsend_005fx509_005frdn_005fsequence-68"></a></var><br>
<blockquote><p><var>session</var>: is a pointer to a <code>gnutls_session_t</code> structure.
<p><var>status</var>: is 0 or 1
<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 advertize
it's trusted CAs to the peer. If status is zero then the default behaviour will
take effect, which is to advertize the server's trusted CAs.
<p>This function has no effect in clients, and in authentication methods other than
certificate with X.509 certificates.
</p></blockquote></div>
<h4 class="subheading">gnutls_certificate_server_set_request</h4>
<p><a name="gnutls_005fcertificate_005fserver_005fset_005frequest"></a>
<div class="defun">
— Function: void <b>gnutls_certificate_server_set_request</b> (<var>gnutls_session_t session, gnutls_certificate_request_t req</var>)<var><a name="index-gnutls_005fcertificate_005fserver_005fset_005frequest-69"></a></var><br>
<blockquote><p><var>session</var>: is an <code>gnutls_session_t</code> structure.
<p><var>req</var>: is one of GNUTLS_CERT_REQUEST, GNUTLS_CERT_REQUIRE
<p>This function specifies if we (in case of a server) are going
to send a certificate request message to the client. If <code>req</code>
is GNUTLS_CERT_REQUIRE then the server will return an 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.
</p></blockquote></div>
<h4 class="subheading">gnutls_certificate_server_set_retrieve_function</h4>
<p><a name="gnutls_005fcertificate_005fserver_005fset_005fretrieve_005ffunction"></a>
<div class="defun">
— Function: void <b>gnutls_certificate_server_set_retrieve_function</b> (<var>gnutls_certificate_credentials_t cred, gnutls_certificate_server_retrieve_function * func</var>)<var><a name="index-gnutls_005fcertificate_005fserver_005fset_005fretrieve_005ffunction-70"></a></var><br>
<blockquote><p><var>cred</var>: is a <code>gnutls_certificate_credentials_t</code> structure.
<p><var>func</var>: is the callback function
<p>This function sets a callback to be called in order to retrieve the certificate
to be used in the handshake.
The callback's function prototype is:
int (*callback)(gnutls_session_t, gnutls_retr_st* st);
<p><code>st</code> should contain the certificates and private keys.
<p>If the callback function is provided then gnutls will call it, in the
handshake, after the certificate request message has been received.
<p>The callback function should set the certificate list to be sent, and
return 0 on success. The value (-1) indicates error and the handshake
will be terminated.
</p></blockquote></div>
<h4 class="subheading">gnutls_certificate_set_dh_params</h4>
<p><a name="gnutls_005fcertificate_005fset_005fdh_005fparams"></a>
<div class="defun">
— Function: void <b>gnutls_certificate_set_dh_params</b> (<var>gnutls_certificate_credentials_t res, gnutls_dh_params_t dh_params</var>)<var><a name="index-gnutls_005fcertificate_005fset_005fdh_005fparams-71"></a></var><br>
<blockquote><p><var>res</var>: is a gnutls_certificate_credentials_t structure
<p><var>dh_params</var>: is a structure that holds diffie hellman parameters.
<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 if you
deallocate the parameters before the certificate is deallocated,
you must change the parameters stored in the certificate first.
</p></blockquote></div>
<h4 class="subheading">gnutls_certificate_set_params_function</h4>
<p><a name="gnutls_005fcertificate_005fset_005fparams_005ffunction"></a>
<div class="defun">
— Function: void <b>gnutls_certificate_set_params_function</b> (<var>gnutls_certificate_credentials_t res, gnutls_params_function * func</var>)<var><a name="index-gnutls_005fcertificate_005fset_005fparams_005ffunction-72"></a></var><br>
<blockquote><p><var>res</var>: is a gnutls_certificate_credentials_t structure
<p><var>func</var>: is the function to be called
<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 zero on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_certificate_set_rsa_export_params</h4>
<p><a name="gnutls_005fcertificate_005fset_005frsa_005fexport_005fparams"></a>
<div class="defun">
— Function: void <b>gnutls_certificate_set_rsa_export_params</b> (<var>gnutls_certificate_credentials_t res, gnutls_rsa_params_t rsa_params</var>)<var><a name="index-gnutls_005fcertificate_005fset_005frsa_005fexport_005fparams-73"></a></var><br>
<blockquote><p><var>res</var>: is a gnutls_certificate_credentials_t structure
<p><var>rsa_params</var>: is a structure that holds temporary RSA parameters.
<p>This function will set the temporary RSA parameters for a certificate
server to use. These parameters will be used in RSA-EXPORT
cipher suites.
</p></blockquote></div>
<h4 class="subheading">gnutls_certificate_set_verify_flags</h4>
<p><a name="gnutls_005fcertificate_005fset_005fverify_005fflags"></a>
<div class="defun">
— Function: void <b>gnutls_certificate_set_verify_flags</b> (<var>gnutls_certificate_credentials_t res, unsigned int flags</var>)<var><a name="index-gnutls_005fcertificate_005fset_005fverify_005fflags-74"></a></var><br>
<blockquote><p><var>res</var>: is a gnutls_certificate_credentials_t structure
<p><var>flags</var>: are the flags
<p>This function will set the flags to be used at verification of the
certificates. Flags must be OR of the
<code>gnutls_certificate_verify_flags</code> enumerations.
</p></blockquote></div>
<h4 class="subheading">gnutls_certificate_set_verify_limits</h4>
<p><a name="gnutls_005fcertificate_005fset_005fverify_005flimits"></a>
<div class="defun">
— Function: void <b>gnutls_certificate_set_verify_limits</b> (<var>gnutls_certificate_credentials_t res, unsigned int max_bits, unsigned int max_depth</var>)<var><a name="index-gnutls_005fcertificate_005fset_005fverify_005flimits-75"></a></var><br>
<blockquote><p><var>res</var>: is a gnutls_certificate_credentials structure
<p><var>max_bits</var>: is the number of bits of an acceptable certificate (default 8200)
<p><var>max_depth</var>: is maximum depth of the verification of a certificate chain (default 5)
<p>This function will set some upper limits for the default verification function,
<code>gnutls_certificate_verify_peers2()</code>, to avoid denial of service attacks.
</p></blockquote></div>
<h4 class="subheading">gnutls_certificate_set_x509_crl_file</h4>
<p><a name="gnutls_005fcertificate_005fset_005fx509_005fcrl_005ffile"></a>
<div class="defun">
— Function: int <b>gnutls_certificate_set_x509_crl_file</b> (<var>gnutls_certificate_credentials_t res, const char * crlfile, gnutls_x509_crt_fmt_t type</var>)<var><a name="index-gnutls_005fcertificate_005fset_005fx509_005fcrl_005ffile-76"></a></var><br>
<blockquote><p><var>res</var>: is an <code>gnutls_certificate_credentials_t</code> structure.
<p><var>crlfile</var>: is a file containing the list of verified CRLs (DER or PEM list)
<p><var>type</var>: is PEM or DER
<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>gnutls_certificate_verify_peers2()</code>.
This function may be called multiple times.
<p>Returns the number of CRLs processed or a negative value on error.
</p></blockquote></div>
<h4 class="subheading">gnutls_certificate_set_x509_crl_mem</h4>
<p><a name="gnutls_005fcertificate_005fset_005fx509_005fcrl_005fmem"></a>
<div class="defun">
— Function: int <b>gnutls_certificate_set_x509_crl_mem</b> (<var>gnutls_certificate_credentials_t res, const gnutls_datum_t * CRL, gnutls_x509_crt_fmt_t type</var>)<var><a name="index-gnutls_005fcertificate_005fset_005fx509_005fcrl_005fmem-77"></a></var><br>
<blockquote><p><var>res</var>: is an <code>gnutls_certificate_credentials_t</code> structure.
<p><var>CRL</var>: is a list of trusted CRLs. They should have been verified before.
<p><var>type</var>: is DER or PEM
<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>gnutls_certificate_verify_peers2()</code>.
This function may be called multiple times.
<p>Returns the number of CRLs processed or a negative value on error.
</p></blockquote></div>
<h4 class="subheading">gnutls_certificate_set_x509_crl</h4>
<p><a name="gnutls_005fcertificate_005fset_005fx509_005fcrl"></a>
<div class="defun">
— Function: int <b>gnutls_certificate_set_x509_crl</b> (<var>gnutls_certificate_credentials_t res, gnutls_x509_crl_t * crl_list, int crl_list_size</var>)<var><a name="index-gnutls_005fcertificate_005fset_005fx509_005fcrl-78"></a></var><br>
<blockquote><p><var>res</var>: is an <code>gnutls_certificate_credentials_t</code> structure.
<p><var>crl_list</var>: is a list of trusted CRLs. They should have been verified before.
<p><var>crl_list_size</var>: holds the size of the crl_list
<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>gnutls_certificate_verify_peers2()</code>.
This function may be called multiple times.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_certificate_set_x509_key_file</h4>
<p><a name="gnutls_005fcertificate_005fset_005fx509_005fkey_005ffile"></a>
<div class="defun">
— Function: int <b>gnutls_certificate_set_x509_key_file</b> (<var>gnutls_certificate_credentials_t res, const char * CERTFILE, const char * KEYFILE, gnutls_x509_crt_fmt_t type</var>)<var><a name="index-gnutls_005fcertificate_005fset_005fx509_005fkey_005ffile-79"></a></var><br>
<blockquote><p><var>res</var>: is an <code>gnutls_certificate_credentials_t</code> structure.
<p><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><var>KEYFILE</var>: is a file that contains the private key
<p><var>type</var>: is PEM or DER
<p>This function sets a certificate/private key pair in the
gnutls_certificate_credentials_t structure. This function may be called
more than once (in case multiple keys/certificates exist for the
server).
<p>Currently only PKCS-1 encoded RSA and DSA private keys are accepted by
this function.
</p></blockquote></div>
<h4 class="subheading">gnutls_certificate_set_x509_key_mem</h4>
<p><a name="gnutls_005fcertificate_005fset_005fx509_005fkey_005fmem"></a>
<div class="defun">
— Function: int <b>gnutls_certificate_set_x509_key_mem</b> (<var>gnutls_certificate_credentials_t res, const gnutls_datum_t * cert, const gnutls_datum_t * key, gnutls_x509_crt_fmt_t type</var>)<var><a name="index-gnutls_005fcertificate_005fset_005fx509_005fkey_005fmem-80"></a></var><br>
<blockquote><p><var>res</var>: is an <code>gnutls_certificate_credentials_t</code> structure.
<p><var>cert</var>: contains a certificate list (path) for the specified private key
<p><var>key</var>: is the private key
<p><var>type</var>: is PEM or DER
<p>This function sets a certificate/private key pair in the
gnutls_certificate_credentials_t structure. This function may be called
more than once (in case multiple keys/certificates exist for the
server).
<p><strong>Currently are supported:</strong> RSA PKCS-1 encoded private keys,
DSA private keys.
<p>DSA private keys are encoded the OpenSSL way, which is an ASN.1
DER sequence of 6 INTEGERs - version, p, q, g, pub, priv.
<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>If the certificate and the private key are given in PEM encoding
then the strings that hold their values must be null terminated.
</p></blockquote></div>
<h4 class="subheading">gnutls_certificate_set_x509_key</h4>
<p><a name="gnutls_005fcertificate_005fset_005fx509_005fkey"></a>
<div class="defun">
— Function: int <b>gnutls_certificate_set_x509_key</b> (<var>gnutls_certificate_credentials_t res, gnutls_x509_crt_t * cert_list, int cert_list_size, gnutls_x509_privkey_t key</var>)<var><a name="index-gnutls_005fcertificate_005fset_005fx509_005fkey-81"></a></var><br>
<blockquote><p><var>res</var>: is an <code>gnutls_certificate_credentials_t</code> structure.
<p><var>cert_list</var>: contains a certificate list (path) for the specified private key
<p><var>cert_list_size</var>: holds the size of the certificate list
<p><var>key</var>: is a gnutls_x509_privkey_t key
<p>This function sets a certificate/private key pair in the
gnutls_certificate_credentials_t structure. This function may be called
more than once (in case multiple keys/certificates exist for the
server).
</p></blockquote></div>
<h4 class="subheading">gnutls_certificate_set_x509_simple_pkcs12_file</h4>
<p><a name="gnutls_005fcertificate_005fset_005fx509_005fsimple_005fpkcs12_005ffile"></a>
<div class="defun">
— Function: int <b>gnutls_certificate_set_x509_simple_pkcs12_file</b> (<var>gnutls_certificate_credentials_t res, const char * pkcs12file, gnutls_x509_crt_fmt_t type, const char * password</var>)<var><a name="index-gnutls_005fcertificate_005fset_005fx509_005fsimple_005fpkcs12_005ffile-82"></a></var><br>
<blockquote><p><var>res</var>: is an <code>gnutls_certificate_credentials_t</code> structure.
<p><var>pkcs12file</var>: filename of file containing PKCS<code>12</code> blob.
<p><var>type</var>: is PEM or DER of the <code>pkcs12file</code>.
<p><var>password</var>: optional password used to decrypt PKCS<code>12</code> file, bags and keys.
<p>This function sets a certificate/private key pair and/or a CRL in
the gnutls_certificate_credentials_t structure. This function may
be called more than once (in case multiple keys/certificates exist
for the server).
<p><strong>MAC:</strong> ed PKCS<code>12</code> files are supported. Encrypted PKCS<code>12</code> bags are
supported. Encrypted PKCS<code>8</code> private keys are supported. However,
only password based security, and the same password for all
operations, are supported.
<p>The private keys may be RSA PKCS<code>1</code> or DSA private keys encoded in
the OpenSSL way.
<p>PKCS<code>12</code> file may contain many keys and/or certificates, and there
is no way to identify which key/certificate pair you want. You
should make sure the PKCS<code>12</code> file only contain one key/certificate
pair and/or one CRL.
<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><strong>Return value:</strong> Returns 0 on success, or an error code.
</p></blockquote></div>
<h4 class="subheading">gnutls_certificate_set_x509_trust_file</h4>
<p><a name="gnutls_005fcertificate_005fset_005fx509_005ftrust_005ffile"></a>
<div class="defun">
— Function: int <b>gnutls_certificate_set_x509_trust_file</b> (<var>gnutls_certificate_credentials_t res, const char * cafile, gnutls_x509_crt_fmt_t type</var>)<var><a name="index-gnutls_005fcertificate_005fset_005fx509_005ftrust_005ffile-83"></a></var><br>
<blockquote><p><var>res</var>: is an <code>gnutls_certificate_credentials_t</code> structure.
<p><var>cafile</var>: is a file containing the list of trusted CAs (DER or PEM list)
<p><var>type</var>: is PEM or DER
<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>gnutls_certificate_verify_peers2()</code>.
This function may be called multiple times.
<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>gnutls_certificate_send_x509_rdn_sequence()</code>.
<p>Returns the number of certificates processed or a negative
value on error.
</p></blockquote></div>
<h4 class="subheading">gnutls_certificate_set_x509_trust_mem</h4>
<p><a name="gnutls_005fcertificate_005fset_005fx509_005ftrust_005fmem"></a>
<div class="defun">
— Function: int <b>gnutls_certificate_set_x509_trust_mem</b> (<var>gnutls_certificate_credentials_t res, const gnutls_datum_t * ca, gnutls_x509_crt_fmt_t type</var>)<var><a name="index-gnutls_005fcertificate_005fset_005fx509_005ftrust_005fmem-84"></a></var><br>
<blockquote><p><var>res</var>: is an <code>gnutls_certificate_credentials_t</code> structure.
<p><var>ca</var>: is a list of trusted CAs or a DER certificate
<p><var>type</var>: is DER or PEM
<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>gnutls_certificate_verify_peers2()</code>.
This function may be called multiple times.
<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>gnutls_certificate_send_x509_rdn_sequence()</code>.
<p>Returns the number of certificates processed or a negative
value on error.
</p></blockquote></div>
<h4 class="subheading">gnutls_certificate_set_x509_trust</h4>
<p><a name="gnutls_005fcertificate_005fset_005fx509_005ftrust"></a>
<div class="defun">
— Function: int <b>gnutls_certificate_set_x509_trust</b> (<var>gnutls_certificate_credentials_t res, gnutls_x509_crt_t * ca_list, int ca_list_size</var>)<var><a name="index-gnutls_005fcertificate_005fset_005fx509_005ftrust-85"></a></var><br>
<blockquote><p><var>res</var>: is an <code>gnutls_certificate_credentials_t</code> structure.
<p><var>ca_list</var>: is a list of trusted CAs
<p><var>ca_list_size</var>: holds the size of the CA list
<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>gnutls_certificate_verify_peers2()</code>.
This function may be called multiple times.
<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>gnutls_certificate_send_x509_rdn_sequence()</code>.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_certificate_type_get_name</h4>
<p><a name="gnutls_005fcertificate_005ftype_005fget_005fname"></a>
<div class="defun">
— Function: const char * <b>gnutls_certificate_type_get_name</b> (<var>gnutls_certificate_type_t type</var>)<var><a name="index-gnutls_005fcertificate_005ftype_005fget_005fname-86"></a></var><br>
<blockquote><p><var>type</var>: is a certificate type
<p>Returns a string (or NULL) that contains the name
of the specified certificate type.
</p></blockquote></div>
<h4 class="subheading">gnutls_certificate_type_get</h4>
<p><a name="gnutls_005fcertificate_005ftype_005fget"></a>
<div class="defun">
— Function: gnutls_certificate_type_t <b>gnutls_certificate_type_get</b> (<var>gnutls_session_t session</var>)<var><a name="index-gnutls_005fcertificate_005ftype_005fget-87"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p>Returns the currently used certificate type. The certificate type
is by default X.509, unless it is negotiated as a TLS extension.
</p></blockquote></div>
<h4 class="subheading">gnutls_certificate_type_set_priority</h4>
<p><a name="gnutls_005fcertificate_005ftype_005fset_005fpriority"></a>
<div class="defun">
— Function: int <b>gnutls_certificate_type_set_priority</b> (<var>gnutls_session_t session, const int * list</var>)<var><a name="index-gnutls_005fcertificate_005ftype_005fset_005fpriority-88"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p><var>list</var>: is a 0 terminated list of gnutls_certificate_type_t elements.
<p>Sets the priority on the certificate types supported by gnutls.
Priority is higher for types specified before others.
After specifying the types you want, you must append a 0.
Note that the certificate type priority is set on the client.
The server does not use the cert type priority except for disabling
types that were not specified.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_certificate_verify_peers2</h4>
<p><a name="gnutls_005fcertificate_005fverify_005fpeers2"></a>
<div class="defun">
— Function: int <b>gnutls_certificate_verify_peers2</b> (<var>gnutls_session_t session, unsigned int * status</var>)<var><a name="index-gnutls_005fcertificate_005fverify_005fpeers2-89"></a></var><br>
<blockquote><p><var>session</var>: is a gnutls session
<p><var>status</var>: is the output of the verification
<p>This function will try to verify the peer's certificate and return
its status (trusted, invalid etc.). The value of <code>status</code> should
be one or more of the gnutls_certificate_status_t enumerated
elements bitwise or'd. 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>gnutls_certificate_set_verify_limits()</code>.
<p>Note that you must also check the peer's name in order to check if
the verified certificate belongs to the actual peer.
<p>Returns a negative error code on error and zero on success.
<p>This is the same as <code>gnutls_x509_verify_certificate()</code> and uses the
loaded CAs in the credentials as trusted CAs.
<p>Note that some commonly used X.509 Certificate Authorities are
still using Version 1 certificates. If you want to accept them,
you need to call <code>gnutls_certificate_set_verify_flags()</code> with, e.g.,
<code>GNUTLS_VERIFY_ALLOW_X509_V1_CA_CRT</code> parameter.
</p></blockquote></div>
<h4 class="subheading">gnutls_certificate_verify_peers</h4>
<p><a name="gnutls_005fcertificate_005fverify_005fpeers"></a>
<div class="defun">
— Function: int <b>gnutls_certificate_verify_peers</b> (<var>gnutls_session_t session</var>)<var><a name="index-gnutls_005fcertificate_005fverify_005fpeers-90"></a></var><br>
<blockquote><p><var>session</var>: is a gnutls session
<p>This function will try to verify the peer's certificate and return
its status (trusted, invalid etc.). However you must also check
the peer's name in order to check if the verified certificate
belongs to the actual peer.
<p>The return value should be one or more of the
gnutls_certificate_status_t enumerated elements bitwise or'd, or a
negative value on error.
<p>This is the same as <code>gnutls_x509_verify_certificate()</code>.
<p><strong>Deprecated:</strong> Use <code>gnutls_certificate_verify_peers2()</code> instead.
</p></blockquote></div>
<h4 class="subheading">gnutls_check_version</h4>
<p><a name="gnutls_005fcheck_005fversion"></a>
<div class="defun">
— Function: const char * <b>gnutls_check_version</b> (<var>const char * req_version</var>)<var><a name="index-gnutls_005fcheck_005fversion-91"></a></var><br>
<blockquote><p><var>req_version</var>: the version to check
<p>Check that the version of the library is at minimum the requested one
and return the version string; return NULL if the condition is not
satisfied. If a NULL is passed to this function, no check is done,
but the version string is simply returned.
</p></blockquote></div>
<h4 class="subheading">gnutls_cipher_get_key_size</h4>
<p><a name="gnutls_005fcipher_005fget_005fkey_005fsize"></a>
<div class="defun">
— Function: size_t <b>gnutls_cipher_get_key_size</b> (<var>gnutls_cipher_algorithm_t algorithm</var>)<var><a name="index-gnutls_005fcipher_005fget_005fkey_005fsize-92"></a></var><br>
<blockquote><p><var>algorithm</var>: is an encryption algorithm
<p>Returns the length (in bytes) of the given cipher's key size.
Returns 0 if the given cipher is invalid.
</p></blockquote></div>
<h4 class="subheading">gnutls_cipher_get_name</h4>
<p><a name="gnutls_005fcipher_005fget_005fname"></a>
<div class="defun">
— Function: const char * <b>gnutls_cipher_get_name</b> (<var>gnutls_cipher_algorithm_t algorithm</var>)<var><a name="index-gnutls_005fcipher_005fget_005fname-93"></a></var><br>
<blockquote><p><var>algorithm</var>: is an encryption algorithm
<p>Returns a pointer to a string that contains the name
of the specified cipher or NULL.
</p></blockquote></div>
<h4 class="subheading">gnutls_cipher_get</h4>
<p><a name="gnutls_005fcipher_005fget"></a>
<div class="defun">
— Function: gnutls_cipher_algorithm_t <b>gnutls_cipher_get</b> (<var>gnutls_session_t session</var>)<var><a name="index-gnutls_005fcipher_005fget-94"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p>Returns the currently used cipher.
</p></blockquote></div>
<h4 class="subheading">gnutls_cipher_set_priority</h4>
<p><a name="gnutls_005fcipher_005fset_005fpriority"></a>
<div class="defun">
— Function: int <b>gnutls_cipher_set_priority</b> (<var>gnutls_session_t session, const int * list</var>)<var><a name="index-gnutls_005fcipher_005fset_005fpriority-95"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p><var>list</var>: is a 0 terminated list of gnutls_cipher_algorithm_t elements.
<p>Sets the priority on the ciphers supported by gnutls.
Priority is higher for ciphers specified before others.
After specifying the ciphers you want, you must append a 0.
Note that the priority is set on the client. The server does
not use the algorithm's priority except for disabling
algorithms that were not specified.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_cipher_suite_get_name</h4>
<p><a name="gnutls_005fcipher_005fsuite_005fget_005fname"></a>
<div class="defun">
— Function: const char * <b>gnutls_cipher_suite_get_name</b> (<var>gnutls_kx_algorithm_t kx_algorithm, gnutls_cipher_algorithm_t cipher_algorithm, gnutls_mac_algorithm_t mac_algorithm</var>)<var><a name="index-gnutls_005fcipher_005fsuite_005fget_005fname-96"></a></var><br>
<blockquote><p><var>kx_algorithm</var>: is a Key exchange algorithm
<p><var>cipher_algorithm</var>: is a cipher algorithm
<p><var>mac_algorithm</var>: is a MAC algorithm
<p>Returns a string that contains the name of a TLS
cipher suite, specified by the given algorithms, or NULL.
<p>Note that the full cipher suite name must be prepended
by TLS or SSL depending of the protocol in use.
</p></blockquote></div>
<h4 class="subheading">gnutls_compression_get_name</h4>
<p><a name="gnutls_005fcompression_005fget_005fname"></a>
<div class="defun">
— Function: const char * <b>gnutls_compression_get_name</b> (<var>gnutls_compression_method_t algorithm</var>)<var><a name="index-gnutls_005fcompression_005fget_005fname-97"></a></var><br>
<blockquote><p><var>algorithm</var>: is a Compression algorithm
<p>Returns a pointer to a string that contains the name
of the specified compression algorithm or NULL.
</p></blockquote></div>
<h4 class="subheading">gnutls_compression_get</h4>
<p><a name="gnutls_005fcompression_005fget"></a>
<div class="defun">
— Function: gnutls_compression_method_t <b>gnutls_compression_get</b> (<var>gnutls_session_t session</var>)<var><a name="index-gnutls_005fcompression_005fget-98"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p>Returns the currently used compression method.
</p></blockquote></div>
<h4 class="subheading">gnutls_compression_set_priority</h4>
<p><a name="gnutls_005fcompression_005fset_005fpriority"></a>
<div class="defun">
— Function: int <b>gnutls_compression_set_priority</b> (<var>gnutls_session_t session, const int * list</var>)<var><a name="index-gnutls_005fcompression_005fset_005fpriority-99"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p><var>list</var>: is a 0 terminated list of gnutls_compression_method_t elements.
<p>Sets the priority on the compression algorithms supported by gnutls.
Priority is higher for algorithms specified before others.
After specifying the algorithms you want, you must append a 0.
Note that the priority is set on the client. The server does
not use the algorithm's priority except for disabling
algorithms that were not specified.
<p>TLS 1.0 does not define any compression algorithms except
NULL. Other compression algorithms are to be considered
as gnutls extensions.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_credentials_clear</h4>
<p><a name="gnutls_005fcredentials_005fclear"></a>
<div class="defun">
— Function: void <b>gnutls_credentials_clear</b> (<var>gnutls_session_t session</var>)<var><a name="index-gnutls_005fcredentials_005fclear-100"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p>Clears all the credentials previously set in this session.
</p></blockquote></div>
<h4 class="subheading">gnutls_credentials_set</h4>
<p><a name="gnutls_005fcredentials_005fset"></a>
<div class="defun">
— Function: int <b>gnutls_credentials_set</b> (<var>gnutls_session_t session, gnutls_credentials_type_t type, void * cred</var>)<var><a name="index-gnutls_005fcredentials_005fset-101"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p><var>type</var>: is the type of the credentials
<p><var>cred</var>: is a pointer to a structure.
<p>Sets the needed credentials for the specified type.
Eg username, password - or public and private keys etc.
The (void* cred) parameter is a structure that depends on the
specified type and on the current session (client or server).
[ In order to minimize memory usage, and share credentials between
several threads gnutls keeps a pointer to cred, and not the whole cred
structure. Thus you will have to keep the structure allocated until
you call <code>gnutls_deinit()</code>. ]
<p>For GNUTLS_CRD_ANON cred should be gnutls_anon_client_credentials_t in case of a client.
In case of a server it should be gnutls_anon_server_credentials_t.
<p>For GNUTLS_CRD_SRP cred should be gnutls_srp_client_credentials_t
in case of a client, and gnutls_srp_server_credentials_t, in case
of a server.
<p>For GNUTLS_CRD_CERTIFICATE cred should be gnutls_certificate_credentials_t.
</p></blockquote></div>
<h4 class="subheading">gnutls_db_check_entry</h4>
<p><a name="gnutls_005fdb_005fcheck_005fentry"></a>
<div class="defun">
— Function: int <b>gnutls_db_check_entry</b> (<var>gnutls_session_t session, gnutls_datum_t session_entry</var>)<var><a name="index-gnutls_005fdb_005fcheck_005fentry-102"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p><var>session_entry</var>: is the session data (not key)
<p>This function returns GNUTLS_E_EXPIRED, if the database entry
has expired or 0 otherwise. This function is to be used when
you want to clear unnesessary session which occupy space in your
backend.
</p></blockquote></div>
<h4 class="subheading">gnutls_db_get_ptr</h4>
<p><a name="gnutls_005fdb_005fget_005fptr"></a>
<div class="defun">
— Function: void * <b>gnutls_db_get_ptr</b> (<var>gnutls_session_t session</var>)<var><a name="index-gnutls_005fdb_005fget_005fptr-103"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p>Returns the pointer that will be sent to db store, retrieve and delete functions, as
the first argument.
</p></blockquote></div>
<h4 class="subheading">gnutls_db_remove_session</h4>
<p><a name="gnutls_005fdb_005fremove_005fsession"></a>
<div class="defun">
— Function: void <b>gnutls_db_remove_session</b> (<var>gnutls_session_t session</var>)<var><a name="index-gnutls_005fdb_005fremove_005fsession-104"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<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>gnutls_deinit()</code> is called.
<p>Normally <code>gnutls_deinit()</code> will remove abnormally terminated sessions.
</p></blockquote></div>
<h4 class="subheading">gnutls_db_set_cache_expiration</h4>
<p><a name="gnutls_005fdb_005fset_005fcache_005fexpiration"></a>
<div class="defun">
— Function: void <b>gnutls_db_set_cache_expiration</b> (<var>gnutls_session_t session, int seconds</var>)<var><a name="index-gnutls_005fdb_005fset_005fcache_005fexpiration-105"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p><var>seconds</var>: is the number of seconds.
<p>Sets the expiration time for resumed sessions. The default is 3600 (one hour)
at the time writing this.
</p></blockquote></div>
<h4 class="subheading">gnutls_db_set_ptr</h4>
<p><a name="gnutls_005fdb_005fset_005fptr"></a>
<div class="defun">
— Function: void <b>gnutls_db_set_ptr</b> (<var>gnutls_session_t session, void * ptr</var>)<var><a name="index-gnutls_005fdb_005fset_005fptr-106"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p><var>ptr</var>: is the pointer
<p>Sets the pointer that will be provided to db store, retrieve and delete functions, as
the first argument.
</p></blockquote></div>
<h4 class="subheading">gnutls_db_set_remove_function</h4>
<p><a name="gnutls_005fdb_005fset_005fremove_005ffunction"></a>
<div class="defun">
— Function: void <b>gnutls_db_set_remove_function</b> (<var>gnutls_session_t session, gnutls_db_remove_func rem_func</var>)<var><a name="index-gnutls_005fdb_005fset_005fremove_005ffunction-107"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p><var>rem_func</var>: is the function.
<p>Sets the function that will be used to remove data from the resumed
sessions database. This function must return 0 on success.
<p>The first argument to <code>rem_func()</code> will be null unless <code>gnutls_db_set_ptr()</code>
has been called.
</p></blockquote></div>
<h4 class="subheading">gnutls_db_set_retrieve_function</h4>
<p><a name="gnutls_005fdb_005fset_005fretrieve_005ffunction"></a>
<div class="defun">
— Function: void <b>gnutls_db_set_retrieve_function</b> (<var>gnutls_session_t session, gnutls_db_retr_func retr_func</var>)<var><a name="index-gnutls_005fdb_005fset_005fretrieve_005ffunction-108"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p><var>retr_func</var>: is the function.
<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>The datum's data must be allocated using the function
<code>gnutls_malloc()</code>.
<p>The first argument to <code>retr_func()</code> will be null unless <code>gnutls_db_set_ptr()</code>
has been called.
</p></blockquote></div>
<h4 class="subheading">gnutls_db_set_store_function</h4>
<p><a name="gnutls_005fdb_005fset_005fstore_005ffunction"></a>
<div class="defun">
— Function: void <b>gnutls_db_set_store_function</b> (<var>gnutls_session_t session, gnutls_db_store_func store_func</var>)<var><a name="index-gnutls_005fdb_005fset_005fstore_005ffunction-109"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p><var>store_func</var>: is the function
<p>Sets the function that will be used to store data from the resumed
sessions database. This function must remove 0 on success.
<p>The first argument to <code>store_func()</code> will be null unless <code>gnutls_db_set_ptr()</code>
has been called.
</p></blockquote></div>
<h4 class="subheading">gnutls_deinit</h4>
<p><a name="gnutls_005fdeinit"></a>
<div class="defun">
— Function: void <b>gnutls_deinit</b> (<var>gnutls_session_t session</var>)<var><a name="index-gnutls_005fdeinit-110"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p>This function clears all buffers associated with the <code>session</code>.
This function will also remove session data from the session database
if the session was terminated abnormally.
</p></blockquote></div>
<h4 class="subheading">gnutls_dh_get_group</h4>
<p><a name="gnutls_005fdh_005fget_005fgroup"></a>
<div class="defun">
— Function: int <b>gnutls_dh_get_group</b> (<var>gnutls_session_t session, gnutls_datum_t * raw_gen, gnutls_datum_t * raw_prime</var>)<var><a name="index-gnutls_005fdh_005fget_005fgroup-111"></a></var><br>
<blockquote><p><var>session</var>: is a gnutls session
<p><var>raw_gen</var>: will hold the generator.
<p><var>raw_prime</var>: will hold the prime.
<p>This function will return the group parameters used in the last Diffie Hellman
authentication 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>gnutls_free()</code>.
<p>Returns a negative value in case of an error.
</p></blockquote></div>
<h4 class="subheading">gnutls_dh_get_peers_public_bits</h4>
<p><a name="gnutls_005fdh_005fget_005fpeers_005fpublic_005fbits"></a>
<div class="defun">
— Function: int <b>gnutls_dh_get_peers_public_bits</b> (<var>gnutls_session_t session</var>)<var><a name="index-gnutls_005fdh_005fget_005fpeers_005fpublic_005fbits-112"></a></var><br>
<blockquote><p><var>session</var>: is a gnutls session
<p>This function will return the bits used in the last Diffie Hellman authentication
with the peer. Should be used for both anonymous and ephemeral diffie Hellman.
Returns a negative value in case of an error.
</p></blockquote></div>
<h4 class="subheading">gnutls_dh_get_prime_bits</h4>
<p><a name="gnutls_005fdh_005fget_005fprime_005fbits"></a>
<div class="defun">
— Function: int <b>gnutls_dh_get_prime_bits</b> (<var>gnutls_session_t session</var>)<var><a name="index-gnutls_005fdh_005fget_005fprime_005fbits-113"></a></var><br>
<blockquote><p><var>session</var>: is a gnutls session
<p>This function will return the bits of the prime used in the last Diffie Hellman authentication
with the peer. Should be used for both anonymous and ephemeral diffie Hellman.
Returns a negative value in case of an error.
</p></blockquote></div>
<h4 class="subheading">gnutls_dh_get_pubkey</h4>
<p><a name="gnutls_005fdh_005fget_005fpubkey"></a>
<div class="defun">
— Function: int <b>gnutls_dh_get_pubkey</b> (<var>gnutls_session_t session, gnutls_datum_t * raw_key</var>)<var><a name="index-gnutls_005fdh_005fget_005fpubkey-114"></a></var><br>
<blockquote><p><var>session</var>: is a gnutls session
<p><var>raw_key</var>: will hold the public key.
<p>This function will return the peer's public key used in the last Diffie Hellman authentication.
This function should be used for both anonymous and ephemeral diffie Hellman.
The output parameters must be freed with <code>gnutls_free()</code>.
<p>Returns a negative value in case of an error.
</p></blockquote></div>
<h4 class="subheading">gnutls_dh_get_secret_bits</h4>
<p><a name="gnutls_005fdh_005fget_005fsecret_005fbits"></a>
<div class="defun">
— Function: int <b>gnutls_dh_get_secret_bits</b> (<var>gnutls_session_t session</var>)<var><a name="index-gnutls_005fdh_005fget_005fsecret_005fbits-115"></a></var><br>
<blockquote><p><var>session</var>: is a gnutls session
<p>This function will return the bits used in the last Diffie Hellman authentication
with the peer. Should be used for both anonymous and ephemeral diffie Hellman.
Returns a negative value in case of an error.
</p></blockquote></div>
<h4 class="subheading">gnutls_dh_params_cpy</h4>
<p><a name="gnutls_005fdh_005fparams_005fcpy"></a>
<div class="defun">
— Function: int <b>gnutls_dh_params_cpy</b> (<var>gnutls_dh_params_t dst, gnutls_dh_params_t src</var>)<var><a name="index-gnutls_005fdh_005fparams_005fcpy-116"></a></var><br>
<blockquote><p><var>dst</var>: Is the destination structure, which should be initialized.
<p><var>src</var>: Is the source structure
<p>This function will copy the DH parameters structure from source
to destination.
</p></blockquote></div>
<h4 class="subheading">gnutls_dh_params_deinit</h4>
<p><a name="gnutls_005fdh_005fparams_005fdeinit"></a>
<div class="defun">
— Function: void <b>gnutls_dh_params_deinit</b> (<var>gnutls_dh_params_t dh_params</var>)<var><a name="index-gnutls_005fdh_005fparams_005fdeinit-117"></a></var><br>
<blockquote><p><var>dh_params</var>: Is a structure that holds the prime numbers
<p>This function will deinitialize the DH parameters structure.
</p></blockquote></div>
<h4 class="subheading">gnutls_dh_params_export_pkcs3</h4>
<p><a name="gnutls_005fdh_005fparams_005fexport_005fpkcs3"></a>
<div class="defun">
— Function: int <b>gnutls_dh_params_export_pkcs3</b> (<var>gnutls_dh_params_t params, gnutls_x509_crt_fmt_t format, unsigned char * params_data, size_t * params_data_size</var>)<var><a name="index-gnutls_005fdh_005fparams_005fexport_005fpkcs3-118"></a></var><br>
<blockquote><p><var>params</var>: Holds the DH parameters
<p><var>format</var>: the format of output params. One of PEM or DER.
<p><var>params_data</var>: will contain a PKCS3 DHParams structure PEM or DER encoded
<p><var>params_data_size</var>: holds the size of params_data (and will be replaced by the actual size of parameters)
<p>This function will export the given dh parameters to a PKCS3
DHParams structure. This is the format generated by "openssl dhparam" tool.
If the buffer provided is not long enough to hold the output, then
GNUTLS_E_SHORT_MEMORY_BUFFER will be returned.
<p>If the structure is PEM encoded, it will have a header
of "BEGIN DH PARAMETERS".
<p>In case of failure a negative value will be returned, and
0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_dh_params_export_raw</h4>
<p><a name="gnutls_005fdh_005fparams_005fexport_005fraw"></a>
<div class="defun">
— Function: int <b>gnutls_dh_params_export_raw</b> (<var>gnutls_dh_params_t params, gnutls_datum_t * prime, gnutls_datum_t * generator, unsigned int * bits</var>)<var><a name="index-gnutls_005fdh_005fparams_005fexport_005fraw-119"></a></var><br>
<blockquote><p><var>params</var>: Holds the DH parameters
<p><var>prime</var>: will hold the new prime
<p><var>generator</var>: will hold the new generator
<p><var>bits</var>: if non null will hold is the prime's number of bits
<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>gnutls_malloc()</code> and will be stored in the appropriate datum.
</p></blockquote></div>
<h4 class="subheading">gnutls_dh_params_generate2</h4>
<p><a name="gnutls_005fdh_005fparams_005fgenerate2"></a>
<div class="defun">
— Function: int <b>gnutls_dh_params_generate2</b> (<var>gnutls_dh_params_t params, unsigned int bits</var>)<var><a name="index-gnutls_005fdh_005fparams_005fgenerate2-120"></a></var><br>
<blockquote><p><var>params</var>: Is the structure that the DH parameters will be stored
<p><var>bits</var>: is the prime's number of bits
<p>This function will generate a new pair of prime and generator for use in
the Diffie-Hellman key exchange. The new parameters will be allocated using
<code>gnutls_malloc()</code> and will be stored in the appropriate datum.
This function is normally slow.
<p>Note that the bits value should be one of 768, 1024, 2048, 3072 or 4096.
Also note that the DH parameters are only useful to servers.
Since clients use the parameters sent by the server, it's of
no use to call this in client side.
</p></blockquote></div>
<h4 class="subheading">gnutls_dh_params_import_pkcs3</h4>
<p><a name="gnutls_005fdh_005fparams_005fimport_005fpkcs3"></a>
<div class="defun">
— Function: int <b>gnutls_dh_params_import_pkcs3</b> (<var>gnutls_dh_params_t params, const gnutls_datum_t * pkcs3_params, gnutls_x509_crt_fmt_t format</var>)<var><a name="index-gnutls_005fdh_005fparams_005fimport_005fpkcs3-121"></a></var><br>
<blockquote><p><var>params</var>: A structure where the parameters will be copied to
<p><var>pkcs3_params</var>: should contain a PKCS3 DHParams structure PEM or DER encoded
<p><var>format</var>: the format of params. PEM or DER.
<p>This function will extract the DHParams found in a PKCS3 formatted
structure. This is the format generated by "openssl dhparam" tool.
<p>If the structure is PEM encoded, it should have a header
of "BEGIN DH PARAMETERS".
<p>In case of failure a negative value will be returned, and
0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_dh_params_import_raw</h4>
<p><a name="gnutls_005fdh_005fparams_005fimport_005fraw"></a>
<div class="defun">
— Function: int <b>gnutls_dh_params_import_raw</b> (<var>gnutls_dh_params_t dh_params, const gnutls_datum_t * prime, const gnutls_datum_t * generator</var>)<var><a name="index-gnutls_005fdh_005fparams_005fimport_005fraw-122"></a></var><br>
<blockquote><p><var>dh_params</var>: Is a structure that will hold the prime numbers
<p><var>prime</var>: holds the new prime
<p><var>generator</var>: holds the new generator
<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></blockquote></div>
<h4 class="subheading">gnutls_dh_params_init</h4>
<p><a name="gnutls_005fdh_005fparams_005finit"></a>
<div class="defun">
— Function: int <b>gnutls_dh_params_init</b> (<var>gnutls_dh_params_t * dh_params</var>)<var><a name="index-gnutls_005fdh_005fparams_005finit-123"></a></var><br>
<blockquote><p><var>dh_params</var>: Is a structure that will hold the prime numbers
<p>This function will initialize the DH parameters structure.
</p></blockquote></div>
<h4 class="subheading">gnutls_dh_set_prime_bits</h4>
<p><a name="gnutls_005fdh_005fset_005fprime_005fbits"></a>
<div class="defun">
— Function: void <b>gnutls_dh_set_prime_bits</b> (<var>gnutls_session_t session, unsigned int bits</var>)<var><a name="index-gnutls_005fdh_005fset_005fprime_005fbits-124"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p><var>bits</var>: is the number of bits
<p>This function sets the number of bits, for use in an
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>In the client side it sets the minimum accepted number of bits.
If a server sends a prime with less bits than that
GNUTLS_E_DH_PRIME_UNACCEPTABLE will be returned by the
handshake.
</p></blockquote></div>
<h4 class="subheading">gnutls_error_is_fatal</h4>
<p><a name="gnutls_005ferror_005fis_005ffatal"></a>
<div class="defun">
— Function: int <b>gnutls_error_is_fatal</b> (<var>int error</var>)<var><a name="index-gnutls_005ferror_005fis_005ffatal-125"></a></var><br>
<blockquote><p><var>error</var>: is an error returned by a gnutls function. Error should be a negative value.
<p>If a function returns a negative value you may feed that value
to this function to see if it is fatal. Returns 1 for a fatal
error 0 otherwise. However you may want to check the
error code manually, since some non-fatal errors to the protocol
may be fatal for you (your program).
<p>This is only useful if you are dealing with errors from the
record layer or the handshake layer.
</p></blockquote></div>
<h4 class="subheading">gnutls_error_to_alert</h4>
<p><a name="gnutls_005ferror_005fto_005falert"></a>
<div class="defun">
— Function: int <b>gnutls_error_to_alert</b> (<var>int err, int * level</var>)<var><a name="index-gnutls_005ferror_005fto_005falert-126"></a></var><br>
<blockquote><p><var>err</var>: is a negative integer
<p><var>level</var>: the alert level will be stored there
<p>Returns 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 err == GNUTLS_E_REHANDSHAKE, where a warning
alert should be sent to the peer indicating that no renegotiation will
be performed.
<p>If the return value is GNUTLS_E_INVALID_REQUEST, then there was no
mapping to an alert.
</p></blockquote></div>
<h4 class="subheading">gnutls_fingerprint</h4>
<p><a name="gnutls_005ffingerprint"></a>
<div class="defun">
— Function: int <b>gnutls_fingerprint</b> (<var>gnutls_digest_algorithm_t algo, const gnutls_datum_t * data, void * result, size_t * result_size</var>)<var><a name="index-gnutls_005ffingerprint-127"></a></var><br>
<blockquote><p><var>algo</var>: is a digest algorithm
<p><var>data</var>: is the data
<p><var>result</var>: is the place where the result will be copied (may be null).
<p><var>result_size</var>: should hold the size of the result. The actual size
of the returned result will also be copied there.
<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>This is the usual way to calculate a fingerprint of an X.509
DER encoded certificate. Note however that the fingerprint
of an OpenPGP is not just a hash and cannot be calculated with
this function.
<p>Returns a negative value in case of an error.
</p></blockquote></div>
<h4 class="subheading">gnutls_free</h4>
<p><a name="gnutls_005ffree"></a>
<div class="defun">
— Function: void <b>gnutls_free</b> (<var>void * ptr</var>)<var><a name="index-gnutls_005ffree-128"></a></var><br>
<blockquote><p>This function will free data pointed by ptr.
<p>The deallocation function used is the one set by <code>gnutls_global_set_mem_functions()</code>.
</p></blockquote></div>
<h4 class="subheading">gnutls_global_deinit</h4>
<p><a name="gnutls_005fglobal_005fdeinit"></a>
<div class="defun">
— Function: void <b>gnutls_global_deinit</b> (<var> void</var>)<var><a name="index-gnutls_005fglobal_005fdeinit-129"></a></var><br>
<blockquote>
<p>This function deinitializes the global data, that were initialized
using <code>gnutls_global_init()</code>.
<p>Note! This function is not thread safe. See the discussion for
<code>gnutls_global_init()</code> for more information.
</p></blockquote></div>
<h4 class="subheading">gnutls_global_init</h4>
<p><a name="gnutls_005fglobal_005finit"></a>
<div class="defun">
— Function: int <b>gnutls_global_init</b> (<var> void</var>)<var><a name="index-gnutls_005fglobal_005finit-130"></a></var><br>
<blockquote>
<p>This function initializes the global data to defaults.
Every gnutls application has a global data which holds common parameters
shared by gnutls session structures.
You must call <code>gnutls_global_deinit()</code> when gnutls usage is no longer needed
Returns zero on success.
<p>Note that this function will also initialize libgcrypt, if it has not
been initialized before. Thus if you want to manually initialize libgcrypt
you must do it before calling this function. This is useful in cases you
want to disable libgcrypt's internal lockings etc.
<p>This function increment a global counter, so that
<code>gnutls_global_deinit()</code> only releases resources when it has been
called as many times as <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.
<p>Note! This function is not thread safe. If two threads call this
function simultaneously, they can cause a race between checking
the global counter and incrementing it, causing both threads to
execute the library initialization code. That would lead to a
memory leak. To handle this, your application could invoke this
function after aquiring a thread mutex. To ignore the potential
memory leak is also an option.
</p></blockquote></div>
<h4 class="subheading">gnutls_global_set_log_function</h4>
<p><a name="gnutls_005fglobal_005fset_005flog_005ffunction"></a>
<div class="defun">
— Function: void <b>gnutls_global_set_log_function</b> (<var>gnutls_log_func log_func</var>)<var><a name="index-gnutls_005fglobal_005fset_005flog_005ffunction-131"></a></var><br>
<blockquote><p><var>log_func</var>: it's a log function
<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>gnutls_log_func is of the form,
void (*gnutls_log_func)( int level, const char*);
</p></blockquote></div>
<h4 class="subheading">gnutls_global_set_log_level</h4>
<p><a name="gnutls_005fglobal_005fset_005flog_005flevel"></a>
<div class="defun">
— Function: void <b>gnutls_global_set_log_level</b> (<var>int level</var>)<var><a name="index-gnutls_005fglobal_005fset_005flog_005flevel-132"></a></var><br>
<blockquote><p><var>level</var>: it's an integer from 0 to 9.
<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>Use a log level over 10 to enable all debugging options.
</p></blockquote></div>
<h4 class="subheading">gnutls_global_set_mem_functions</h4>
<p><a name="gnutls_005fglobal_005fset_005fmem_005ffunctions"></a>
<div class="defun">
— Function: void <b>gnutls_global_set_mem_functions</b> (<var>gnutls_alloc_function alloc_func, gnutls_alloc_function secure_alloc_func, gnutls_is_secure_function is_secure_func, gnutls_realloc_function realloc_func, gnutls_free_function free_func</var>)<var><a name="index-gnutls_005fglobal_005fset_005fmem_005ffunctions-133"></a></var><br>
<blockquote><p><var>alloc_func</var>: it's the default memory allocation function. Like <code>malloc()</code>.
<p><var>secure_alloc_func</var>: This is the memory allocation function that will be used for sensitive data.
<p><var>is_secure_func</var>: a function that returns 0 if the memory given is not secure. May be NULL.
<p><var>realloc_func</var>: A realloc function
<p><var>free_func</var>: The function that frees allocated data. Must accept a NULL pointer.
<p>This is the function were you set the memory allocation functions gnutls
is going to use. By default the libc's allocation functions (<code>malloc()</code>, <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 (ie the gcrypt allocation functions).
<p>This function must be called before <code>gnutls_global_init()</code> is called.
</p></blockquote></div>
<h4 class="subheading">gnutls_handshake_get_last_in</h4>
<p><a name="gnutls_005fhandshake_005fget_005flast_005fin"></a>
<div class="defun">
— Function: gnutls_handshake_description_t <b>gnutls_handshake_get_last_in</b> (<var>gnutls_session_t session</var>)<var><a name="index-gnutls_005fhandshake_005fget_005flast_005fin-134"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p>Returns the last handshake message received. 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>Check gnutls.h for the available handshake descriptions.
</p></blockquote></div>
<h4 class="subheading">gnutls_handshake_get_last_out</h4>
<p><a name="gnutls_005fhandshake_005fget_005flast_005fout"></a>
<div class="defun">
— Function: gnutls_handshake_description_t <b>gnutls_handshake_get_last_out</b> (<var>gnutls_session_t session</var>)<var><a name="index-gnutls_005fhandshake_005fget_005flast_005fout-135"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p>Returns the last handshake message sent. 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>Check gnutls.h for the available handshake descriptions.
</p></blockquote></div>
<h4 class="subheading">gnutls_handshake_set_max_packet_length</h4>
<p><a name="gnutls_005fhandshake_005fset_005fmax_005fpacket_005flength"></a>
<div class="defun">
— Function: void <b>gnutls_handshake_set_max_packet_length</b> (<var>gnutls_session_t session, size_t max</var>)<var><a name="index-gnutls_005fhandshake_005fset_005fmax_005fpacket_005flength-136"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p><var>max</var>: is the maximum number.
<p>This function will set the maximum size of a handshake message.
Handshake messages over this size are rejected.
The default value is 16kb which is large enough. Set this to 0 if you do not want
to set an upper limit.
</p></blockquote></div>
<h4 class="subheading">gnutls_handshake_set_private_extensions</h4>
<p><a name="gnutls_005fhandshake_005fset_005fprivate_005fextensions"></a>
<div class="defun">
— Function: void <b>gnutls_handshake_set_private_extensions</b> (<var>gnutls_session_t session, int allow</var>)<var><a name="index-gnutls_005fhandshake_005fset_005fprivate_005fextensions-137"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p><var>allow</var>: is an integer (0 or 1)
<p>This function will enable or disable the use of private
cipher suites (the ones that start with 0xFF). By default
or if <code>allow</code> is 0 then these cipher suites will not be
advertized nor used.
<p>Unless this function is called with the option to allow (1), then
no compression algorithms, like LZO. That is because these algorithms
are not yet defined in any RFC or even internet draft.
<p>Enabling the private ciphersuites when talking to other than gnutls
servers and clients may cause interoperability problems.
</p></blockquote></div>
<h4 class="subheading">gnutls_handshake</h4>
<p><a name="gnutls_005fhandshake"></a>
<div class="defun">
— Function: int <b>gnutls_handshake</b> (<var>gnutls_session_t session</var>)<var><a name="index-gnutls_005fhandshake-138"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p>This function does the handshake of the TLS/SSL protocol,
and initializes the TLS connection.
<p>This function will fail if any problem is encountered,
and will return a negative error code. In case of a client,
if the client has asked to resume a session, but the server couldn't,
then a full handshake will be performed.
<p>The non-fatal errors such as GNUTLS_E_AGAIN and GNUTLS_E_INTERRUPTED
interrupt the handshake procedure, which should be later be resumed.
Call this function again, until it returns 0; cf.
<code>gnutls_record_get_direction()</code> and <code>gnutls_error_is_fatal()</code>.
<p>If this function is called by a server after a rehandshake request then
GNUTLS_E_GOT_APPLICATION_DATA or GNUTLS_E_WARNING_ALERT_RECEIVED
may be returned. Note that these are non fatal errors, only in the
specific case of a rehandshake. Their meaning is that the client
rejected the rehandshake request.
</p></blockquote></div>
<h4 class="subheading">gnutls_hex_decode</h4>
<p><a name="gnutls_005fhex_005fdecode"></a>
<div class="defun">
— Function: int <b>gnutls_hex_decode</b> (<var>const gnutls_datum_t * hex_data, char * result, size_t * result_size</var>)<var><a name="index-gnutls_005fhex_005fdecode-139"></a></var><br>
<blockquote><p><var>hex_data</var>: contain the encoded data
<p><var>result</var>: the place where decoded data will be copied
<p><var>result_size</var>: holds the size of the result
<p>This function will decode the given encoded data, using the hex encoding
used by PSK password files.
<p>Note that hex_data should be null terminated.
<p>Returns GNUTLS_E_SHORT_MEMORY_BUFFER if the buffer given is not long enough,
or 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_hex_encode</h4>
<p><a name="gnutls_005fhex_005fencode"></a>
<div class="defun">
— Function: int <b>gnutls_hex_encode</b> (<var>const gnutls_datum_t * data, char * result, size_t * result_size</var>)<var><a name="index-gnutls_005fhex_005fencode-140"></a></var><br>
<blockquote><p><var>data</var>: contain the raw data
<p><var>result</var>: the place where hex data will be copied
<p><var>result_size</var>: holds the size of the result
<p>This function will convert the given data to printable data, using the hex
encoding, as used in the PSK password files.
<p>Returns GNUTLS_E_SHORT_MEMORY_BUFFER if the buffer given is not long enough,
or 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_init</h4>
<p><a name="gnutls_005finit"></a>
<div class="defun">
— Function: int <b>gnutls_init</b> (<var>gnutls_session_t * session, gnutls_connection_end_t con_end</var>)<var><a name="index-gnutls_005finit-141"></a></var><br>
<blockquote><p><var>session</var>: is a pointer to a <code>gnutls_session_t</code> structure.
<p><var>con_end</var>: is used to indicate if this session is to be used for server or
client. Can be one of GNUTLS_CLIENT and GNUTLS_SERVER.
<p>This function initializes the current session to null. Every session
must be initialized before use, so internal structures can be allocated.
This function allocates structures which can only be free'd
by calling <code>gnutls_deinit()</code>. Returns zero on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_kx_get_name</h4>
<p><a name="gnutls_005fkx_005fget_005fname"></a>
<div class="defun">
— Function: const char * <b>gnutls_kx_get_name</b> (<var>gnutls_kx_algorithm_t algorithm</var>)<var><a name="index-gnutls_005fkx_005fget_005fname-142"></a></var><br>
<blockquote><p><var>algorithm</var>: is a key exchange algorithm
<p>Returns a pointer to a string that contains the name
of the specified key exchange algorithm or NULL.
</p></blockquote></div>
<h4 class="subheading">gnutls_kx_get</h4>
<p><a name="gnutls_005fkx_005fget"></a>
<div class="defun">
— Function: gnutls_kx_algorithm_t <b>gnutls_kx_get</b> (<var>gnutls_session_t session</var>)<var><a name="index-gnutls_005fkx_005fget-143"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p>Returns the key exchange algorithm used in the last handshake.
</p></blockquote></div>
<h4 class="subheading">gnutls_kx_set_priority</h4>
<p><a name="gnutls_005fkx_005fset_005fpriority"></a>
<div class="defun">
— Function: int <b>gnutls_kx_set_priority</b> (<var>gnutls_session_t session, const int * list</var>)<var><a name="index-gnutls_005fkx_005fset_005fpriority-144"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p><var>list</var>: is a 0 terminated list of gnutls_kx_algorithm_t elements.
<p>Sets the priority on the key exchange algorithms supported by gnutls.
Priority is higher for algorithms specified before others.
After specifying the algorithms you want, you must append a 0.
Note that the priority is set on the client. The server does
not use the algorithm's priority except for disabling
algorithms that were not specified.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_mac_get_name</h4>
<p><a name="gnutls_005fmac_005fget_005fname"></a>
<div class="defun">
— Function: const char * <b>gnutls_mac_get_name</b> (<var>gnutls_mac_algorithm_t algorithm</var>)<var><a name="index-gnutls_005fmac_005fget_005fname-145"></a></var><br>
<blockquote><p><var>algorithm</var>: is a MAC algorithm
<p>Returns a string that contains the name
of the specified MAC algorithm or NULL.
</p></blockquote></div>
<h4 class="subheading">gnutls_mac_get</h4>
<p><a name="gnutls_005fmac_005fget"></a>
<div class="defun">
— Function: gnutls_mac_algorithm_t <b>gnutls_mac_get</b> (<var>gnutls_session_t session</var>)<var><a name="index-gnutls_005fmac_005fget-146"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p>Returns the currently used mac algorithm.
</p></blockquote></div>
<h4 class="subheading">gnutls_mac_set_priority</h4>
<p><a name="gnutls_005fmac_005fset_005fpriority"></a>
<div class="defun">
— Function: int <b>gnutls_mac_set_priority</b> (<var>gnutls_session_t session, const int * list</var>)<var><a name="index-gnutls_005fmac_005fset_005fpriority-147"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p><var>list</var>: is a 0 terminated list of gnutls_mac_algorithm_t elements.
<p>Sets the priority on the mac algorithms supported by gnutls.
Priority is higher for algorithms specified before others.
After specifying the algorithms you want, you must append a 0.
Note that the priority is set on the client. The server does
not use the algorithm's priority except for disabling
algorithms that were not specified.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_malloc</h4>
<p><a name="gnutls_005fmalloc"></a>
<div class="defun">
— Function: void * <b>gnutls_malloc</b> (<var>size_t s</var>)<var><a name="index-gnutls_005fmalloc-148"></a></var><br>
<blockquote>
<p>This function will allocate 's' bytes data, and
return a pointer to memory. This function is supposed
to be used by callbacks.
<p>The allocation function used is the one set by <code>gnutls_global_set_mem_functions()</code>.
</p></blockquote></div>
<h4 class="subheading">gnutls_openpgp_send_key</h4>
<p><a name="gnutls_005fopenpgp_005fsend_005fkey"></a>
<div class="defun">
— Function: void <b>gnutls_openpgp_send_key</b> (<var>gnutls_session_t session, gnutls_openpgp_key_status_t status</var>)<var><a name="index-gnutls_005fopenpgp_005fsend_005fkey-149"></a></var><br>
<blockquote><p><var>session</var>: is a pointer to a <code>gnutls_session_t</code> structure.
<p><var>status</var>: is one of OPENPGP_KEY, or OPENPGP_KEY_FINGERPRINT
<p>This function will order gnutls to send the key fingerprint instead
of the key in the initial handshake procedure. This should be used
with care and only when there is indication or knowledge that the
server can obtain the client's key.
</p></blockquote></div>
<h4 class="subheading">gnutls_pem_base64_decode_alloc</h4>
<p><a name="gnutls_005fpem_005fbase64_005fdecode_005falloc"></a>
<div class="defun">
— Function: int <b>gnutls_pem_base64_decode_alloc</b> (<var>const char * header, const gnutls_datum_t * b64_data, gnutls_datum_t * result</var>)<var><a name="index-gnutls_005fpem_005fbase64_005fdecode_005falloc-150"></a></var><br>
<blockquote><p><var>header</var>: The PEM header (eg. CERTIFICATE)
<p><var>b64_data</var>: contains the encoded data
<p><var>result</var>: the place where decoded data lie
<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
"——BEGIN header" and decode only this part. Otherwise it will decode the
first PEM packet found.
<p>You should use <code>gnutls_free()</code> to free the returned data.
</p></blockquote></div>
<h4 class="subheading">gnutls_pem_base64_decode</h4>
<p><a name="gnutls_005fpem_005fbase64_005fdecode"></a>
<div class="defun">
— Function: int <b>gnutls_pem_base64_decode</b> (<var>const char * header, const gnutls_datum_t * b64_data, unsigned char * result, size_t * result_size</var>)<var><a name="index-gnutls_005fpem_005fbase64_005fdecode-151"></a></var><br>
<blockquote><p><var>header</var>: A null terminated string with the PEM header (eg. CERTIFICATE)
<p><var>b64_data</var>: contain the encoded data
<p><var>result</var>: the place where decoded data will be copied
<p><var>result_size</var>: holds the size of the result
<p>This function will decode the given encoded data. If the header given
is non null this function will search for "——BEGIN header" and decode
only this part. Otherwise it will decode the first PEM packet found.
<p>Returns GNUTLS_E_SHORT_MEMORY_BUFFER if the buffer given is not long enough,
or 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_pem_base64_encode_alloc</h4>
<p><a name="gnutls_005fpem_005fbase64_005fencode_005falloc"></a>
<div class="defun">
— Function: int <b>gnutls_pem_base64_encode_alloc</b> (<var>const char * msg, const gnutls_datum_t * data, gnutls_datum_t * result</var>)<var><a name="index-gnutls_005fpem_005fbase64_005fencode_005falloc-152"></a></var><br>
<blockquote><p><var>msg</var>: is a message to be put in the encoded header
<p><var>data</var>: contains the raw data
<p><var>result</var>: will hold the newly allocated encoded data
<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>You should use <code>gnutls_free()</code> to free the returned data.
</p></blockquote></div>
<h4 class="subheading">gnutls_pem_base64_encode</h4>
<p><a name="gnutls_005fpem_005fbase64_005fencode"></a>
<div class="defun">
— Function: int <b>gnutls_pem_base64_encode</b> (<var>const char * msg, const gnutls_datum_t * data, char * result, size_t * result_size</var>)<var><a name="index-gnutls_005fpem_005fbase64_005fencode-153"></a></var><br>
<blockquote><p><var>msg</var>: is a message to be put in the header
<p><var>data</var>: contain the raw data
<p><var>result</var>: the place where base64 data will be copied
<p><var>result_size</var>: holds the size of the result
<p>This function will convert the given data to printable data, using the base64
encoding. This is the encoding used in PEM messages. If the provided
buffer is not long enough GNUTLS_E_SHORT_MEMORY_BUFFER is returned.
<p>The output string will be null terminated, although the size will not include
the terminating null.
</p></blockquote></div>
<h4 class="subheading">gnutls_perror</h4>
<p><a name="gnutls_005fperror"></a>
<div class="defun">
— Function: void <b>gnutls_perror</b> (<var>int error</var>)<var><a name="index-gnutls_005fperror-154"></a></var><br>
<blockquote><p><var>error</var>: is an error returned by a gnutls function. Error is always a negative value.
<p>This function is like <code>perror()</code>. The only difference is that it accepts an
error number returned by a gnutls function.
</p></blockquote></div>
<h4 class="subheading">gnutls_pk_algorithm_get_name</h4>
<p><a name="gnutls_005fpk_005falgorithm_005fget_005fname"></a>
<div class="defun">
— Function: const char * <b>gnutls_pk_algorithm_get_name</b> (<var>gnutls_pk_algorithm_t algorithm</var>)<var><a name="index-gnutls_005fpk_005falgorithm_005fget_005fname-155"></a></var><br>
<blockquote><p><var>algorithm</var>: is a pk algorithm
<p>Returns a string that contains the name
of the specified public key algorithm or NULL.
</p></blockquote></div>
<h4 class="subheading">gnutls_prf_raw</h4>
<p><a name="gnutls_005fprf_005fraw"></a>
<div class="defun">
— Function: int <b>gnutls_prf_raw</b> (<var>gnutls_session_t session, size_t label_size, const char * label, size_t seed_size, const char * seed, size_t outsize, char * out</var>)<var><a name="index-gnutls_005fprf_005fraw-156"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p><var>label_size</var>: length of the <code>label</code> variable.
<p><var>label</var>: label used in PRF computation, typically a short string.
<p><var>seed_size</var>: length of the <code>seed</code> variable.
<p><var>seed</var>: optional extra data to seed the PRF with.
<p><var>outsize</var>: size of pre-allocated output buffer to hold the output.
<p><var>out</var>: pre-allocate buffer to hold the generated data.
<p>Apply the TLS Pseudo-Random-Function (PRF) using the master secret
on some data.
<p>The <code>label</code> variable usually contain a string denoting the purpose
for the generated data. The <code>seed</code> usually contain 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>Because the output is not guaranteed to be unique for a particular
session unless <code>seed</code> include 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>gnutls_prf()</code> function seed 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><strong>Return value:</strong> Return 0 on success, or an error code.
</p></blockquote></div>
<h4 class="subheading">gnutls_prf</h4>
<p><a name="gnutls_005fprf"></a>
<div class="defun">
— Function: int <b>gnutls_prf</b> (<var>gnutls_session_t session, size_t label_size, const char * label, int server_random_first, size_t extra_size, const char * extra, size_t outsize, char * out</var>)<var><a name="index-gnutls_005fprf-157"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p><var>label_size</var>: length of the <code>label</code> variable.
<p><var>label</var>: label used in PRF computation, typically a short string.
<p><var>server_random_first</var>: non-0 if server random field should be first in seed
<p><var>extra_size</var>: length of the <code>extra</code> variable.
<p><var>extra</var>: optional extra data to seed the PRF with.
<p><var>outsize</var>: size of pre-allocated output buffer to hold the output.
<p><var>out</var>: pre-allocate buffer to hold the generated data.
<p>Apply the TLS Pseudo-Random-Function (PRF) using the master secret
on some data, seeded with the client and server random fields.
<p>The <code>label</code> variable usually contain a string denoting the purpose
for the generated data. The <code>server_random_first</code> indicate whether
the client random field or the server random field should be first
in the seed. Non-0 indicate that the server random field is first,
0 that the client random field is first.
<p>The <code>extra</code> variable can be used to add more data to the seed, after
the random variables. It can be used to tie make sure the
generated output is strongly connected to some additional data
(e.g., a string used in user authentication).
<p>The output is placed in *<code>OUT</code>, which must be pre-allocated.
<p><strong>Return value:</strong> Return 0 on success, or an error code.
</p></blockquote></div>
<h4 class="subheading">gnutls_protocol_get_name</h4>
<p><a name="gnutls_005fprotocol_005fget_005fname"></a>
<div class="defun">
— Function: const char * <b>gnutls_protocol_get_name</b> (<var>gnutls_protocol_t version</var>)<var><a name="index-gnutls_005fprotocol_005fget_005fname-158"></a></var><br>
<blockquote><p><var>version</var>: is a (gnutls) version number
<p>Returns a string that contains the name
of the specified TLS version or NULL.
</p></blockquote></div>
<h4 class="subheading">gnutls_protocol_get_version</h4>
<p><a name="gnutls_005fprotocol_005fget_005fversion"></a>
<div class="defun">
— Function: gnutls_protocol_t <b>gnutls_protocol_get_version</b> (<var>gnutls_session_t session</var>)<var><a name="index-gnutls_005fprotocol_005fget_005fversion-159"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p>Returns the version of the currently used protocol.
</p></blockquote></div>
<h4 class="subheading">gnutls_protocol_set_priority</h4>
<p><a name="gnutls_005fprotocol_005fset_005fpriority"></a>
<div class="defun">
— Function: int <b>gnutls_protocol_set_priority</b> (<var>gnutls_session_t session, const int * list</var>)<var><a name="index-gnutls_005fprotocol_005fset_005fpriority-160"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p><var>list</var>: is a 0 terminated list of gnutls_protocol_t elements.
<p>Sets the priority on the protocol versions supported by gnutls.
This function actually enables or disables protocols. Newer protocol
versions always have highest priority.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_psk_allocate_client_credentials</h4>
<p><a name="gnutls_005fpsk_005fallocate_005fclient_005fcredentials"></a>
<div class="defun">
— Function: int <b>gnutls_psk_allocate_client_credentials</b> (<var>gnutls_psk_client_credentials_t * sc</var>)<var><a name="index-gnutls_005fpsk_005fallocate_005fclient_005fcredentials-161"></a></var><br>
<blockquote><p><var>sc</var>: is a pointer to an <code>gnutls_psk_server_credentials_t</code> structure.
<p>This structure is complex enough to manipulate directly thus
this helper function is provided in order to allocate it.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_psk_allocate_server_credentials</h4>
<p><a name="gnutls_005fpsk_005fallocate_005fserver_005fcredentials"></a>
<div class="defun">
— Function: int <b>gnutls_psk_allocate_server_credentials</b> (<var>gnutls_psk_server_credentials_t * sc</var>)<var><a name="index-gnutls_005fpsk_005fallocate_005fserver_005fcredentials-162"></a></var><br>
<blockquote><p><var>sc</var>: is a pointer to an <code>gnutls_psk_server_credentials_t</code> structure.
<p>This structure is complex enough to manipulate directly thus
this helper function is provided in order to allocate it.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_psk_free_client_credentials</h4>
<p><a name="gnutls_005fpsk_005ffree_005fclient_005fcredentials"></a>
<div class="defun">
— Function: void <b>gnutls_psk_free_client_credentials</b> (<var>gnutls_psk_client_credentials_t sc</var>)<var><a name="index-gnutls_005fpsk_005ffree_005fclient_005fcredentials-163"></a></var><br>
<blockquote><p><var>sc</var>: is an <code>gnutls_psk_client_credentials_t</code> structure.
<p>This structure is complex enough to manipulate directly thus
this helper function is provided in order to free (deallocate) it.
</p></blockquote></div>
<h4 class="subheading">gnutls_psk_free_server_credentials</h4>
<p><a name="gnutls_005fpsk_005ffree_005fserver_005fcredentials"></a>
<div class="defun">
— Function: void <b>gnutls_psk_free_server_credentials</b> (<var>gnutls_psk_server_credentials_t sc</var>)<var><a name="index-gnutls_005fpsk_005ffree_005fserver_005fcredentials-164"></a></var><br>
<blockquote><p><var>sc</var>: is an <code>gnutls_psk_server_credentials_t</code> structure.
<p>This structure is complex enough to manipulate directly thus
this helper function is provided in order to free (deallocate) it.
</p></blockquote></div>
<h4 class="subheading">gnutls_psk_server_get_username</h4>
<p><a name="gnutls_005fpsk_005fserver_005fget_005fusername"></a>
<div class="defun">
— Function: const char * <b>gnutls_psk_server_get_username</b> (<var>gnutls_session_t session</var>)<var><a name="index-gnutls_005fpsk_005fserver_005fget_005fusername-165"></a></var><br>
<blockquote><p><var>session</var>: is a gnutls session
<p>This function will return the username of the peer. This should only be
called in case of PSK authentication and in case of a server.
Returns NULL in case of an error.
</p></blockquote></div>
<h4 class="subheading">gnutls_psk_set_client_credentials_function</h4>
<p><a name="gnutls_005fpsk_005fset_005fclient_005fcredentials_005ffunction"></a>
<div class="defun">
— Function: void <b>gnutls_psk_set_client_credentials_function</b> (<var>gnutls_psk_client_credentials_t cred, gnutls_psk_client_credentials_function * func</var>)<var><a name="index-gnutls_005fpsk_005fset_005fclient_005fcredentials_005ffunction-166"></a></var><br>
<blockquote><p><var>cred</var>: is a <code>gnutls_psk_server_credentials_t</code> structure.
<p><var>func</var>: is the callback function
<p>This function can be used to set a callback to retrieve the username and
password for client PSK authentication.
The callback's function form is:
int (*callback)(gnutls_session_t, char** username,
gnutls_datum* key);
<p>The <code>username</code> and <code>key</code> must be allocated using <code>gnutls_malloc()</code>.
<code>username</code> should be ASCII strings or UTF-8 strings
prepared using the "SASLprep" profile of "stringprep".
<p>The callback function will be called once per handshake.
<p>The callback function should return 0 on success.
-1 indicates an error.
</p></blockquote></div>
<h4 class="subheading">gnutls_psk_set_client_credentials</h4>
<p><a name="gnutls_005fpsk_005fset_005fclient_005fcredentials"></a>
<div class="defun">
— Function: int <b>gnutls_psk_set_client_credentials</b> (<var>gnutls_psk_client_credentials_t res, const char * username, const gnutls_datum * key, unsigned int flags</var>)<var><a name="index-gnutls_005fpsk_005fset_005fclient_005fcredentials-167"></a></var><br>
<blockquote><p><var>res</var>: is an <code>gnutls_psk_client_credentials_t</code> structure.
<p><var>username</var>: is the user's zero-terminated userid
<p><var>key</var>: is the user's key
<p>This function sets the username and password, in a
gnutls_psk_client_credentials_t structure. Those will be used in
PSK authentication. <code>username</code> should be an ASCII
string or UTF-8 strings prepared using the "SASLprep" profile of
"stringprep". The key can be either in raw byte format or in Hex
(not with the '0x' prefix).
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_psk_set_params_function</h4>
<p><a name="gnutls_005fpsk_005fset_005fparams_005ffunction"></a>
<div class="defun">
— Function: void <b>gnutls_psk_set_params_function</b> (<var>gnutls_psk_server_credentials_t res, gnutls_params_function * func</var>)<var><a name="index-gnutls_005fpsk_005fset_005fparams_005ffunction-168"></a></var><br>
<blockquote><p><var>res</var>: is a gnutls_psk_server_credentials_t structure
<p><var>func</var>: is the function to be called
<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 zero on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_psk_set_server_credentials_file</h4>
<p><a name="gnutls_005fpsk_005fset_005fserver_005fcredentials_005ffile"></a>
<div class="defun">
— Function: int <b>gnutls_psk_set_server_credentials_file</b> (<var>gnutls_psk_server_credentials_t res, const char * password_file</var>)<var><a name="index-gnutls_005fpsk_005fset_005fserver_005fcredentials_005ffile-169"></a></var><br>
<blockquote><p><var>res</var>: is an <code>gnutls_psk_server_credentials_t</code> structure.
<p><var>password_file</var>: is the PSK password file (passwd.psk)
<p>This function sets the password file, in a gnutls_psk_server_credentials_t structure.
This password file holds usernames and keys and will be used for PSK authentication.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_psk_set_server_credentials_function</h4>
<p><a name="gnutls_005fpsk_005fset_005fserver_005fcredentials_005ffunction"></a>
<div class="defun">
— Function: void <b>gnutls_psk_set_server_credentials_function</b> (<var>gnutls_psk_server_credentials_t cred, gnutls_psk_server_credentials_function * func</var>)<var><a name="index-gnutls_005fpsk_005fset_005fserver_005fcredentials_005ffunction-170"></a></var><br>
<blockquote><p><var>cred</var>: is a <code>gnutls_psk_server_credentials_t</code> structure.
<p><var>func</var>: is the callback function
<p>This function can be used to set a callback to retrieve the user's PSK credentials.
The callback's function form is:
int (*callback)(gnutls_session_t, const char* username,
gnutls_datum_t* key);
<p><code>username</code> contains the actual username.
The <code>key</code> must be filled in using the <code>gnutls_malloc()</code>.
<p>In case the callback returned a negative number then gnutls will
assume that the username does not exist.
<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></blockquote></div>
<h4 class="subheading">gnutls_psk_set_server_dh_params</h4>
<p><a name="gnutls_005fpsk_005fset_005fserver_005fdh_005fparams"></a>
<div class="defun">
— Function: void <b>gnutls_psk_set_server_dh_params</b> (<var>gnutls_psk_server_credentials_t res, gnutls_dh_params_t dh_params</var>)<var><a name="index-gnutls_005fpsk_005fset_005fserver_005fdh_005fparams-171"></a></var><br>
<blockquote><p><var>res</var>: is a gnutls_psk_server_credentials_t structure
<p><var>dh_params</var>: is a structure that holds diffie hellman parameters.
<p>This function will set the diffie hellman parameters for an anonymous
server to use. These parameters will be used in Diffie Hellman with PSK
cipher suites.
</p></blockquote></div>
<h4 class="subheading">gnutls_psk_set_server_params_function</h4>
<p><a name="gnutls_005fpsk_005fset_005fserver_005fparams_005ffunction"></a>
<div class="defun">
— Function: void <b>gnutls_psk_set_server_params_function</b> (<var>gnutls_psk_server_credentials_t res, gnutls_params_function * func</var>)<var><a name="index-gnutls_005fpsk_005fset_005fserver_005fparams_005ffunction-172"></a></var><br>
<blockquote><p><var>res</var>: is a gnutls_certificate_credentials_t structure
<p><var>func</var>: is the function to be called
<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 zero on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_record_check_pending</h4>
<p><a name="gnutls_005frecord_005fcheck_005fpending"></a>
<div class="defun">
— Function: size_t <b>gnutls_record_check_pending</b> (<var>gnutls_session_t session</var>)<var><a name="index-gnutls_005frecord_005fcheck_005fpending-173"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p>This function checks if there are any data to receive
in the gnutls buffers. Returns the size of that data or 0.
Notice that you may also use <code>select()</code> to check for data in
a TCP connection, instead of this function.
(gnutls leaves some data in the tcp buffer in order for select
to work).
</p></blockquote></div>
<h4 class="subheading">gnutls_record_get_direction</h4>
<p><a name="gnutls_005frecord_005fget_005fdirection"></a>
<div class="defun">
— Function: int <b>gnutls_record_get_direction</b> (<var>gnutls_session_t session</var>)<var><a name="index-gnutls_005frecord_005fget_005fdirection-174"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p>This function provides information about the internals of the record
protocol and is only useful if a prior gnutls function call (e.g.
<code>gnutls_handshake()</code>) was interrupted for some reason, that is, if a function
returned GNUTLS_E_INTERRUPTED or GNUTLS_E_AGAIN. In such a case, you might
want to call <code>select()</code> or <code>poll()</code> before calling the interrupted gnutls
function again. To tell you whether a file descriptor should be selected
for either reading or writing, <code>gnutls_record_get_direction()</code> returns 0 if
the interrupted function was trying to read data, and 1 if it was trying to
write data.
</p></blockquote></div>
<h4 class="subheading">gnutls_record_get_max_size</h4>
<p><a name="gnutls_005frecord_005fget_005fmax_005fsize"></a>
<div class="defun">
— Function: size_t <b>gnutls_record_get_max_size</b> (<var>gnutls_session_t session</var>)<var><a name="index-gnutls_005frecord_005fget_005fmax_005fsize-175"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p>This function returns the maximum record packet size in this connection.
The maximum record size is negotiated by the client after the
first handshake message.
</p></blockquote></div>
<h4 class="subheading">gnutls_record_recv</h4>
<p><a name="gnutls_005frecord_005frecv"></a>
<div class="defun">
— Function: ssize_t <b>gnutls_record_recv</b> (<var>gnutls_session_t session, void * data, size_t sizeofdata</var>)<var><a name="index-gnutls_005frecord_005frecv-176"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p><var>data</var>: the buffer that the data will be read into
<p><var>sizeofdata</var>: the number of requested bytes
<p>This function has the similar semantics with <code>recv()</code>. The only
difference is that is accepts a GNUTLS session, and uses different
error codes.
<p>In the special case that a server requests a renegotiation, the
client may receive an error code of GNUTLS_E_REHANDSHAKE. This
message may be simply ignored, replied with an alert containing
NO_RENEGOTIATION, or replied with a new handshake, depending on
the client's will.
<p>If EINTR is returned by the internal push function (the default is
<code>code</code>{<code>recv()</code>}) then GNUTLS_E_INTERRUPTED will be returned. If
GNUTLS_E_INTERRUPTED or GNUTLS_E_AGAIN is returned, you must call
this function again, with the same parameters; alternatively you
could provide a NULL pointer for data, and 0 for
size. cf. <code>code</code>{<code>gnutls_record_get_direction()</code>}.
<p>A server may also receive GNUTLS_E_REHANDSHAKE when a client has
initiated a handshake. In that case the server can only initiate a
handshake or terminate the connection.
<p>Returns 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>code</code>{count}.
</p></blockquote></div>
<h4 class="subheading">gnutls_record_send</h4>
<p><a name="gnutls_005frecord_005fsend"></a>
<div class="defun">
— Function: ssize_t <b>gnutls_record_send</b> (<var>gnutls_session_t session, const void * data, size_t sizeofdata</var>)<var><a name="index-gnutls_005frecord_005fsend-177"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p><var>data</var>: contains the data to send
<p><var>sizeofdata</var>: is the length of the data
<p>This function has the similar semantics with <code>send()</code>. The only
difference is that is accepts a GNUTLS session, and uses different
error codes.
<p>Note that if the send buffer is full, <code>send()</code> will block this
function. See the <code>send()</code> documentation for full information. You
can replace the default push function by using
<code>gnutls_transport_set_ptr2()</code> with a call to <code>send()</code> with a
MSG_DONTWAIT flag if blocking is a problem.
<p>If the EINTR is returned by the internal push function (the
default is <code>send()</code>} then <code>GNUTLS_E_INTERRUPTED</code> will be returned. If
<code>GNUTLS_E_INTERRUPTED</code> or <code>GNUTLS_E_AGAIN</code> is returned, you must
call this function again, with the same parameters; alternatively
you could provide a <code>NULL</code> pointer for data, and 0 for
size. cf. <code>gnutls_record_get_direction()</code>.
<p>Returns the number of bytes sent, or a negative error code. The
number of bytes sent might be less than <code>sizeofdata</code>. The maximum
number of bytes this function can send in a single call depends on
the negotiated maximum record size.
</p></blockquote></div>
<h4 class="subheading">gnutls_record_set_max_size</h4>
<p><a name="gnutls_005frecord_005fset_005fmax_005fsize"></a>
<div class="defun">
— Function: ssize_t <b>gnutls_record_set_max_size</b> (<var>gnutls_session_t session, size_t size</var>)<var><a name="index-gnutls_005frecord_005fset_005fmax_005fsize-178"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p><var>size</var>: is the new size
<p>This function sets the maximum record packet size in this connection.
This property can only be set to clients. The server may
choose not to accept the requested size.
<p>Acceptable values are 512(=2^9), 1024(=2^10), 2048(=2^11) and 4096(=2^12).
Returns 0 on success. The requested record size does
get in effect immediately only while sending data. The receive
part will take effect after a successful handshake.
<p>This function uses a TLS extension called 'max record size'.
Not all TLS implementations use or even understand this extension.
</p></blockquote></div>
<h4 class="subheading">gnutls_rehandshake</h4>
<p><a name="gnutls_005frehandshake"></a>
<div class="defun">
— Function: int <b>gnutls_rehandshake</b> (<var>gnutls_session_t session</var>)<var><a name="index-gnutls_005frehandshake-179"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p>This function will renegotiate security parameters with the
client. This should only be called in case of a server.
<p>This message informs the peer that we want to renegotiate
parameters (perform a handshake).
<p>If this function succeeds (returns 0), you must call
the <code>gnutls_handshake()</code> function in order to negotiate
the new parameters.
<p>If the client does not wish to renegotiate parameters he
will should with an alert message, thus the return code will be
GNUTLS_E_WARNING_ALERT_RECEIVED and the alert will be
GNUTLS_A_NO_RENEGOTIATION. A client may also choose to ignore
this message.
</p></blockquote></div>
<h4 class="subheading">gnutls_rsa_export_get_modulus_bits</h4>
<p><a name="gnutls_005frsa_005fexport_005fget_005fmodulus_005fbits"></a>
<div class="defun">
— Function: int <b>gnutls_rsa_export_get_modulus_bits</b> (<var>gnutls_session_t session</var>)<var><a name="index-gnutls_005frsa_005fexport_005fget_005fmodulus_005fbits-180"></a></var><br>
<blockquote><p><var>session</var>: is a gnutls session
<p>This function will return the bits used in the last RSA-EXPORT key exchange
with the peer.
Returns a negative value in case of an error.
</p></blockquote></div>
<h4 class="subheading">gnutls_rsa_export_get_pubkey</h4>
<p><a name="gnutls_005frsa_005fexport_005fget_005fpubkey"></a>
<div class="defun">
— Function: int <b>gnutls_rsa_export_get_pubkey</b> (<var>gnutls_session_t session, gnutls_datum_t * exponent, gnutls_datum_t * modulus</var>)<var><a name="index-gnutls_005frsa_005fexport_005fget_005fpubkey-181"></a></var><br>
<blockquote><p><var>session</var>: is a gnutls session
<p><var>exponent</var>: will hold the exponent.
<p><var>modulus</var>: will hold the modulus.
<p>This function will return the peer's public key exponent and
modulus used in the last RSA-EXPORT authentication. The output
parameters must be freed with <code>gnutls_free()</code>.
<p>Returns a negative value in case of an error.
</p></blockquote></div>
<h4 class="subheading">gnutls_rsa_params_cpy</h4>
<p><a name="gnutls_005frsa_005fparams_005fcpy"></a>
<div class="defun">
— Function: int <b>gnutls_rsa_params_cpy</b> (<var>gnutls_rsa_params_t dst, gnutls_rsa_params_t src</var>)<var><a name="index-gnutls_005frsa_005fparams_005fcpy-182"></a></var><br>
<blockquote><p><var>dst</var>: Is the destination structure, which should be initialized.
<p><var>src</var>: Is the source structure
<p>This function will copy the RSA parameters structure from source
to destination.
</p></blockquote></div>
<h4 class="subheading">gnutls_rsa_params_deinit</h4>
<p><a name="gnutls_005frsa_005fparams_005fdeinit"></a>
<div class="defun">
— Function: void <b>gnutls_rsa_params_deinit</b> (<var>gnutls_rsa_params_t rsa_params</var>)<var><a name="index-gnutls_005frsa_005fparams_005fdeinit-183"></a></var><br>
<blockquote><p><var>rsa_params</var>: Is a structure that holds the parameters
<p>This function will deinitialize the RSA parameters structure.
</p></blockquote></div>
<h4 class="subheading">gnutls_rsa_params_export_pkcs1</h4>
<p><a name="gnutls_005frsa_005fparams_005fexport_005fpkcs1"></a>
<div class="defun">
— Function: int <b>gnutls_rsa_params_export_pkcs1</b> (<var>gnutls_rsa_params_t params, gnutls_x509_crt_fmt_t format, unsigned char * params_data, size_t * params_data_size</var>)<var><a name="index-gnutls_005frsa_005fparams_005fexport_005fpkcs1-184"></a></var><br>
<blockquote><p><var>params</var>: Holds the RSA parameters
<p><var>format</var>: the format of output params. One of PEM or DER.
<p><var>params_data</var>: will contain a PKCS1 RSAPublicKey structure PEM or DER encoded
<p><var>params_data_size</var>: holds the size of params_data (and will be replaced by the actual size of parameters)
<p>This function will export the given RSA parameters to a PKCS1
RSAPublicKey structure. If the buffer provided is not long enough to
hold the output, then GNUTLS_E_SHORT_MEMORY_BUFFER will be returned.
<p>If the structure is PEM encoded, it will have a header
of "BEGIN RSA PRIVATE KEY".
<p>In case of failure a negative value will be returned, and
0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_rsa_params_export_raw</h4>
<p><a name="gnutls_005frsa_005fparams_005fexport_005fraw"></a>
<div class="defun">
— Function: int <b>gnutls_rsa_params_export_raw</b> (<var>gnutls_rsa_params_t params, gnutls_datum_t * m, gnutls_datum_t * e, gnutls_datum_t * d, gnutls_datum_t * p, gnutls_datum_t * q, gnutls_datum_t * u, unsigned int * bits</var>)<var><a name="index-gnutls_005frsa_005fparams_005fexport_005fraw-185"></a></var><br>
<blockquote><p><var>params</var>: a structure that holds the rsa parameters
<p><var>m</var>: will hold the modulus
<p><var>e</var>: will hold the public exponent
<p><var>d</var>: will hold the private exponent
<p><var>p</var>: will hold the first prime (p)
<p><var>q</var>: will hold the second prime (q)
<p><var>u</var>: will hold the coefficient
<p><var>bits</var>: if non null will hold the prime's number of bits
<p>This function will export the RSA parameters found in the given
structure. The new parameters will be allocated using
<code>gnutls_malloc()</code> and will be stored in the appropriate datum.
</p></blockquote></div>
<h4 class="subheading">gnutls_rsa_params_generate2</h4>
<p><a name="gnutls_005frsa_005fparams_005fgenerate2"></a>
<div class="defun">
— Function: int <b>gnutls_rsa_params_generate2</b> (<var>gnutls_rsa_params_t params, unsigned int bits</var>)<var><a name="index-gnutls_005frsa_005fparams_005fgenerate2-186"></a></var><br>
<blockquote><p><var>params</var>: The structure where the parameters will be stored
<p><var>bits</var>: is the prime's number of bits
<p>This function will generate new temporary RSA parameters for use in
RSA-EXPORT ciphersuites. This function is normally slow.
<p>Note that if the parameters are to be used in export cipher suites the
bits value should be 512 or less.
Also note that the generation of new RSA parameters is only useful
to servers. Clients use the parameters sent by the server, thus it's
no use calling this in client side.
</p></blockquote></div>
<h4 class="subheading">gnutls_rsa_params_import_pkcs1</h4>
<p><a name="gnutls_005frsa_005fparams_005fimport_005fpkcs1"></a>
<div class="defun">
— Function: int <b>gnutls_rsa_params_import_pkcs1</b> (<var>gnutls_rsa_params_t params, const gnutls_datum_t * pkcs1_params, gnutls_x509_crt_fmt_t format</var>)<var><a name="index-gnutls_005frsa_005fparams_005fimport_005fpkcs1-187"></a></var><br>
<blockquote><p><var>params</var>: A structure where the parameters will be copied to
<p><var>pkcs1_params</var>: should contain a PKCS1 RSAPublicKey structure PEM or DER encoded
<p><var>format</var>: the format of params. PEM or DER.
<p>This function will extract the RSAPublicKey found in a PKCS1 formatted
structure.
<p>If the structure is PEM encoded, it should have a header
of "BEGIN RSA PRIVATE KEY".
<p>In case of failure a negative value will be returned, and
0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_rsa_params_import_raw</h4>
<p><a name="gnutls_005frsa_005fparams_005fimport_005fraw"></a>
<div class="defun">
— Function: int <b>gnutls_rsa_params_import_raw</b> (<var>gnutls_rsa_params_t rsa_params, const gnutls_datum_t * m, const gnutls_datum_t * e, const gnutls_datum_t * d, const gnutls_datum_t * p, const gnutls_datum_t * q, const gnutls_datum_t * u</var>)<var><a name="index-gnutls_005frsa_005fparams_005fimport_005fraw-188"></a></var><br>
<blockquote><p><var>rsa_params</var>: Is a structure will hold the parameters
<p><var>m</var>: holds the modulus
<p><var>e</var>: holds the public exponent
<p><var>d</var>: holds the private exponent
<p><var>p</var>: holds the first prime (p)
<p><var>q</var>: holds the second prime (q)
<p><var>u</var>: holds the coefficient
<p>This function will replace the parameters in the given structure.
The new parameters should be stored in the appropriate gnutls_datum.
</p></blockquote></div>
<h4 class="subheading">gnutls_rsa_params_init</h4>
<p><a name="gnutls_005frsa_005fparams_005finit"></a>
<div class="defun">
— Function: int <b>gnutls_rsa_params_init</b> (<var>gnutls_rsa_params_t * rsa_params</var>)<var><a name="index-gnutls_005frsa_005fparams_005finit-189"></a></var><br>
<blockquote><p><var>rsa_params</var>: Is a structure that will hold the parameters
<p>This function will initialize the temporary RSA parameters structure.
</p></blockquote></div>
<h4 class="subheading">gnutls_server_name_get</h4>
<p><a name="gnutls_005fserver_005fname_005fget"></a>
<div class="defun">
— Function: int <b>gnutls_server_name_get</b> (<var>gnutls_session_t session, void * data, size_t * data_length, unsigned int * type, unsigned int indx</var>)<var><a name="index-gnutls_005fserver_005fname_005fget-190"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p><var>data</var>: will hold the data
<p><var>data_length</var>: will hold the data length. Must hold the maximum size of data.
<p><var>type</var>: will hold the server name indicator type
<p><var>indx</var>: is the index of the server_name
<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>If <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 UTF-8 string.
<p>If <code>data</code> has not enough size to hold the server name GNUTLS_E_SHORT_MEMORY_BUFFER
is returned, and <code>data_length</code> will hold the required size.
<p><code>index</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></blockquote></div>
<h4 class="subheading">gnutls_server_name_set</h4>
<p><a name="gnutls_005fserver_005fname_005fset"></a>
<div class="defun">
— Function: int <b>gnutls_server_name_set</b> (<var>gnutls_session_t session, gnutls_server_name_type_t type, const void * name, size_t name_length</var>)<var><a name="index-gnutls_005fserver_005fname_005fset-191"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p><var>type</var>: specifies the indicator type
<p><var>name</var>: is a string that contains the server name.
<p><var>name_length</var>: holds the length of name
<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>The value of <code>name</code> depends on the <code>ind</code> type. In case of GNUTLS_NAME_DNS,
an ASCII or UTF-8 null terminated string, without the trailing dot, is expected.
IPv4 or IPv6 addresses are not permitted.
</p></blockquote></div>
<h4 class="subheading">gnutls_session_get_client_random</h4>
<p><a name="gnutls_005fsession_005fget_005fclient_005frandom"></a>
<div class="defun">
— Function: const void * <b>gnutls_session_get_client_random</b> (<var>gnutls_session_t session</var>)<var><a name="index-gnutls_005fsession_005fget_005fclient_005frandom-192"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p>Return a pointer to the 32-byte client random field used in the
session. The pointer must not be modified or deallocated.
<p>If a client random value has not yet been established, the output
will be garbage; in particular, a <code>NULL</code> return value should not be
expected.
<p><strong>Return value:</strong> pointer to client random.
</p></blockquote></div>
<h4 class="subheading">gnutls_session_get_data2</h4>
<p><a name="gnutls_005fsession_005fget_005fdata2"></a>
<div class="defun">
— Function: int <b>gnutls_session_get_data2</b> (<var>gnutls_session_t session, gnutls_datum * data</var>)<var><a name="index-gnutls_005fsession_005fget_005fdata2-193"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p>Returns all session parameters, in order to support resuming.
The client should call this, and keep the returned session, if he wants to
resume that current version later by calling <code>gnutls_session_set_data()</code>
This function must be called after a successful handshake. The returned
datum must be freed with <code>gnutls_free()</code>.
<p>Resuming sessions is really useful and speedups connections after a succesful one.
</p></blockquote></div>
<h4 class="subheading">gnutls_session_get_data</h4>
<p><a name="gnutls_005fsession_005fget_005fdata"></a>
<div class="defun">
— Function: int <b>gnutls_session_get_data</b> (<var>gnutls_session_t session, void * session_data, size_t * session_data_size</var>)<var><a name="index-gnutls_005fsession_005fget_005fdata-194"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p><var>session_data</var>: is a pointer to space to hold the session.
<p><var>session_data_size</var>: is the session_data's size, or it will be set by the function.
<p>Returns all session parameters, in order to support resuming.
The client should call this, and keep the returned session, if he wants to
resume that current version later by calling <code>gnutls_session_set_data()</code>
This function must be called after a successful handshake.
<p>Resuming sessions is really useful and speedups connections after a succesful one.
</p></blockquote></div>
<h4 class="subheading">gnutls_session_get_id</h4>
<p><a name="gnutls_005fsession_005fget_005fid"></a>
<div class="defun">
— Function: int <b>gnutls_session_get_id</b> (<var>gnutls_session_t session, void * session_id, size_t * session_id_size</var>)<var><a name="index-gnutls_005fsession_005fget_005fid-195"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p><var>session_id</var>: is a pointer to space to hold the session id.
<p><var>session_id_size</var>: is the session id's size, or it will be set by the function.
<p>Returns the current session id. This can be used if you want to check if
the next session you tried to resume was actually resumed.
This is because resumed sessions have the same sessionID with the
original session.
<p>Session id is some data set by the server, that identify the current session.
In TLS 1.0 and SSL 3.0 session id is always less than 32 bytes.
<p>Returns zero on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_session_get_master_secret</h4>
<p><a name="gnutls_005fsession_005fget_005fmaster_005fsecret"></a>
<div class="defun">
— Function: const void * <b>gnutls_session_get_master_secret</b> (<var>gnutls_session_t session</var>)<var><a name="index-gnutls_005fsession_005fget_005fmaster_005fsecret-196"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p>Return a pointer to the 48-byte master secret in the session. The
pointer must not be modified or deallocated.
<p>If a master secret value has not yet been established, the output
will be garbage; in particular, a <code>NULL</code> return value should not be
expected.
<p>Consider using <code>gnutls_prf()</code> rather than extracting the master
secret and use it to derive further data.
<p><strong>Return value:</strong> pointer to master secret.
</p></blockquote></div>
<h4 class="subheading">gnutls_session_get_ptr</h4>
<p><a name="gnutls_005fsession_005fget_005fptr"></a>
<div class="defun">
— Function: void * <b>gnutls_session_get_ptr</b> (<var>gnutls_session_t session</var>)<var><a name="index-gnutls_005fsession_005fget_005fptr-197"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p>This function will return the user given pointer from the session structure.
This is the pointer set with <code>gnutls_session_set_ptr()</code>.
</p></blockquote></div>
<h4 class="subheading">gnutls_session_get_server_random</h4>
<p><a name="gnutls_005fsession_005fget_005fserver_005frandom"></a>
<div class="defun">
— Function: const void * <b>gnutls_session_get_server_random</b> (<var>gnutls_session_t session</var>)<var><a name="index-gnutls_005fsession_005fget_005fserver_005frandom-198"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p>Return a pointer to the 32-byte server random field used in the
session. The pointer must not be modified or deallocated.
<p>If a server random value has not yet been established, the output
will be garbage; in particular, a <code>NULL</code> return value should not be
expected.
<p><strong>Return value:</strong> pointer to server random.
</p></blockquote></div>
<h4 class="subheading">gnutls_session_is_resumed</h4>
<p><a name="gnutls_005fsession_005fis_005fresumed"></a>
<div class="defun">
— Function: int <b>gnutls_session_is_resumed</b> (<var>gnutls_session_t session</var>)<var><a name="index-gnutls_005fsession_005fis_005fresumed-199"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p>This function will return non zero if this session is a resumed one,
or a zero if this is a new session.
</p></blockquote></div>
<h4 class="subheading">gnutls_session_set_data</h4>
<p><a name="gnutls_005fsession_005fset_005fdata"></a>
<div class="defun">
— Function: int <b>gnutls_session_set_data</b> (<var>gnutls_session_t session, const void * session_data, size_t session_data_size</var>)<var><a name="index-gnutls_005fsession_005fset_005fdata-200"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p><var>session_data</var>: is a pointer to space to hold the session.
<p><var>session_data_size</var>: is the session's size
<p>Sets all session parameters, in order to resume a previously established
session. The session data given must be the one returned by <code>gnutls_session_get_data()</code>.
This function should be called before <code>gnutls_handshake()</code>.
<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>Returns a negative value on error.
</p></blockquote></div>
<h4 class="subheading">gnutls_session_set_ptr</h4>
<p><a name="gnutls_005fsession_005fset_005fptr"></a>
<div class="defun">
— Function: void <b>gnutls_session_set_ptr</b> (<var>gnutls_session_t session, void * ptr</var>)<var><a name="index-gnutls_005fsession_005fset_005fptr-201"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p><var>ptr</var>: is the user pointer
<p>This function will set (associate) the user given pointer to the
session structure. This is pointer can be accessed with
<code>gnutls_session_get_ptr()</code>.
</p></blockquote></div>
<h4 class="subheading">gnutls_set_default_export_priority</h4>
<p><a name="gnutls_005fset_005fdefault_005fexport_005fpriority"></a>
<div class="defun">
— Function: int <b>gnutls_set_default_export_priority</b> (<var>gnutls_session_t session</var>)<var><a name="index-gnutls_005fset_005fdefault_005fexport_005fpriority-202"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p>Sets some default priority on the ciphers, key exchange methods, macs
and compression methods. This is to avoid using the gnutls_*<code>_priority()</code> functions, if
these defaults are ok. This function also includes weak algorithms.
The order is TLS1, SSL3 for protocols, RSA, DHE_DSS,
DHE_RSA, RSA_EXPORT for key exchange algorithms.
SHA, MD5, RIPEMD160 for MAC algorithms,
AES_256_CBC, AES_128_CBC,
and 3DES_CBC, ARCFOUR_128, ARCFOUR_40 for ciphers.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_set_default_priority</h4>
<p><a name="gnutls_005fset_005fdefault_005fpriority"></a>
<div class="defun">
— Function: int <b>gnutls_set_default_priority</b> (<var>gnutls_session_t session</var>)<var><a name="index-gnutls_005fset_005fdefault_005fpriority-203"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p>Sets some default priority on the ciphers, key exchange methods, macs
and compression methods. This is to avoid using the gnutls_*<code>_priority()</code> functions, if
these defaults are ok. You may override any of the following priorities by calling
the appropriate functions.
<p>The order is TLS1, SSL3 for protocols.
RSA, DHE_DSS, DHE_RSA for key exchange
algorithms. SHA, MD5 and RIPEMD160 for MAC algorithms.
AES_128_CBC, 3DES_CBC,
and ARCFOUR_128 for ciphers.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_sign_algorithm_get_name</h4>
<p><a name="gnutls_005fsign_005falgorithm_005fget_005fname"></a>
<div class="defun">
— Function: const char * <b>gnutls_sign_algorithm_get_name</b> (<var>gnutls_sign_algorithm_t sign</var>)<var><a name="index-gnutls_005fsign_005falgorithm_005fget_005fname-204"></a></var><br>
<blockquote><p>Returns a string that contains the name
of the specified sign algorithm or NULL.
</p></blockquote></div>
<h4 class="subheading">gnutls_srp_allocate_client_credentials</h4>
<p><a name="gnutls_005fsrp_005fallocate_005fclient_005fcredentials"></a>
<div class="defun">
— Function: int <b>gnutls_srp_allocate_client_credentials</b> (<var>gnutls_srp_client_credentials_t * sc</var>)<var><a name="index-gnutls_005fsrp_005fallocate_005fclient_005fcredentials-205"></a></var><br>
<blockquote><p><var>sc</var>: is a pointer to an <code>gnutls_srp_server_credentials_t</code> structure.
<p>This structure is complex enough to manipulate directly thus
this helper function is provided in order to allocate it.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_srp_allocate_server_credentials</h4>
<p><a name="gnutls_005fsrp_005fallocate_005fserver_005fcredentials"></a>
<div class="defun">
— Function: int <b>gnutls_srp_allocate_server_credentials</b> (<var>gnutls_srp_server_credentials_t * sc</var>)<var><a name="index-gnutls_005fsrp_005fallocate_005fserver_005fcredentials-206"></a></var><br>
<blockquote><p><var>sc</var>: is a pointer to an <code>gnutls_srp_server_credentials_t</code> structure.
<p>This structure is complex enough to manipulate directly thus
this helper function is provided in order to allocate it.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_srp_base64_decode_alloc</h4>
<p><a name="gnutls_005fsrp_005fbase64_005fdecode_005falloc"></a>
<div class="defun">
— Function: int <b>gnutls_srp_base64_decode_alloc</b> (<var>const gnutls_datum_t * b64_data, gnutls_datum_t * result</var>)<var><a name="index-gnutls_005fsrp_005fbase64_005fdecode_005falloc-207"></a></var><br>
<blockquote><p><var>b64_data</var>: contains the encoded data
<p><var>result</var>: the place where decoded data lie
<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 found in libsrp.
<p>You should use <code>gnutls_free()</code> to free the returned data.
</p></blockquote></div>
<h4 class="subheading">gnutls_srp_base64_decode</h4>
<p><a name="gnutls_005fsrp_005fbase64_005fdecode"></a>
<div class="defun">
— Function: int <b>gnutls_srp_base64_decode</b> (<var>const gnutls_datum_t * b64_data, char * result, size_t * result_size</var>)<var><a name="index-gnutls_005fsrp_005fbase64_005fdecode-208"></a></var><br>
<blockquote><p><var>b64_data</var>: contain the encoded data
<p><var>result</var>: the place where decoded data will be copied
<p><var>result_size</var>: holds the size of the result
<p>This function will decode the given encoded data, using the base64 encoding
found in libsrp.
<p>Note that b64_data should be null terminated.
<p>Returns GNUTLS_E_SHORT_MEMORY_BUFFER if the buffer given is not long enough,
or 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_srp_base64_encode_alloc</h4>
<p><a name="gnutls_005fsrp_005fbase64_005fencode_005falloc"></a>
<div class="defun">
— Function: int <b>gnutls_srp_base64_encode_alloc</b> (<var>const gnutls_datum_t * data, gnutls_datum_t * result</var>)<var><a name="index-gnutls_005fsrp_005fbase64_005fencode_005falloc-209"></a></var><br>
<blockquote><p><var>data</var>: contains the raw data
<p><var>result</var>: will hold the newly allocated encoded data
<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>You should use <code>gnutls_free()</code> to free the returned data.
</p></blockquote></div>
<h4 class="subheading">gnutls_srp_base64_encode</h4>
<p><a name="gnutls_005fsrp_005fbase64_005fencode"></a>
<div class="defun">
— Function: int <b>gnutls_srp_base64_encode</b> (<var>const gnutls_datum_t * data, char * result, size_t * result_size</var>)<var><a name="index-gnutls_005fsrp_005fbase64_005fencode-210"></a></var><br>
<blockquote><p><var>data</var>: contain the raw data
<p><var>result</var>: the place where base64 data will be copied
<p><var>result_size</var>: holds the size of the result
<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></blockquote></div>
<h4 class="subheading">gnutls_srp_free_client_credentials</h4>
<p><a name="gnutls_005fsrp_005ffree_005fclient_005fcredentials"></a>
<div class="defun">
— Function: void <b>gnutls_srp_free_client_credentials</b> (<var>gnutls_srp_client_credentials_t sc</var>)<var><a name="index-gnutls_005fsrp_005ffree_005fclient_005fcredentials-211"></a></var><br>
<blockquote><p><var>sc</var>: is an <code>gnutls_srp_client_credentials_t</code> structure.
<p>This structure is complex enough to manipulate directly thus
this helper function is provided in order to free (deallocate) it.
</p></blockquote></div>
<h4 class="subheading">gnutls_srp_free_server_credentials</h4>
<p><a name="gnutls_005fsrp_005ffree_005fserver_005fcredentials"></a>
<div class="defun">
— Function: void <b>gnutls_srp_free_server_credentials</b> (<var>gnutls_srp_server_credentials_t sc</var>)<var><a name="index-gnutls_005fsrp_005ffree_005fserver_005fcredentials-212"></a></var><br>
<blockquote><p><var>sc</var>: is an <code>gnutls_srp_server_credentials_t</code> structure.
<p>This structure is complex enough to manipulate directly thus
this helper function is provided in order to free (deallocate) it.
</p></blockquote></div>
<h4 class="subheading">gnutls_srp_server_get_username</h4>
<p><a name="gnutls_005fsrp_005fserver_005fget_005fusername"></a>
<div class="defun">
— Function: const char * <b>gnutls_srp_server_get_username</b> (<var>gnutls_session_t session</var>)<var><a name="index-gnutls_005fsrp_005fserver_005fget_005fusername-213"></a></var><br>
<blockquote><p><var>session</var>: is a gnutls session
<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></blockquote></div>
<h4 class="subheading">gnutls_srp_set_client_credentials_function</h4>
<p><a name="gnutls_005fsrp_005fset_005fclient_005fcredentials_005ffunction"></a>
<div class="defun">
— Function: void <b>gnutls_srp_set_client_credentials_function</b> (<var>gnutls_srp_client_credentials_t cred, gnutls_srp_client_credentials_function * func</var>)<var><a name="index-gnutls_005fsrp_005fset_005fclient_005fcredentials_005ffunction-214"></a></var><br>
<blockquote><p><var>cred</var>: is a <code>gnutls_srp_server_credentials_t</code> structure.
<p><var>func</var>: is the callback function
<p>This function can be used to set a callback to retrieve the username and
password for client SRP authentication.
The callback's function form is:
int (*callback)(gnutls_session_t, unsigned int times, char** username,
char** password);
<p>The <code>username</code> and <code>password</code> must be allocated using <code>gnutls_malloc()</code>.
<code>times</code> will be 0 the first time called, and 1 the second.
<code>username</code> and <code>password</code> should be ASCII strings or UTF-8 strings
prepared using the "SASLprep" profile of "stringprep".
<p>The callback function will be called once or twice per handshake.
The first time called, is before the ciphersuite is negotiated.
At that time if the callback returns a negative error code,
the callback will be called again if SRP has been
negotiated. This uses a special TLS-SRP idiom in order to avoid
asking the user for SRP password and username if the server does
not support SRP.
<p>The callback should not return a negative error code the second
time called, since the handshake procedure will be aborted.
<p>The callback function should return 0 on success.
-1 indicates an error.
</p></blockquote></div>
<h4 class="subheading">gnutls_srp_set_client_credentials</h4>
<p><a name="gnutls_005fsrp_005fset_005fclient_005fcredentials"></a>
<div class="defun">
— Function: int <b>gnutls_srp_set_client_credentials</b> (<var>gnutls_srp_client_credentials_t res, const char * username, const char * password</var>)<var><a name="index-gnutls_005fsrp_005fset_005fclient_005fcredentials-215"></a></var><br>
<blockquote><p><var>res</var>: is an <code>gnutls_srp_client_credentials_t</code> structure.
<p><var>username</var>: is the user's userid
<p><var>password</var>: is the user's password
<p>This function sets the username and password, in a gnutls_srp_client_credentials_t structure.
Those will be used in SRP authentication. <code>username</code> and <code>password</code> should be ASCII
strings or UTF-8 strings prepared using the "SASLprep" profile of "stringprep".
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_srp_set_server_credentials_file</h4>
<p><a name="gnutls_005fsrp_005fset_005fserver_005fcredentials_005ffile"></a>
<div class="defun">
— Function: int <b>gnutls_srp_set_server_credentials_file</b> (<var>gnutls_srp_server_credentials_t res, const char * password_file, const char * password_conf_file</var>)<var><a name="index-gnutls_005fsrp_005fset_005fserver_005fcredentials_005ffile-216"></a></var><br>
<blockquote><p><var>res</var>: is an <code>gnutls_srp_server_credentials_t</code> structure.
<p><var>password_file</var>: is the SRP password file (tpasswd)
<p><var>password_conf_file</var>: is the SRP password conf file (tpasswd.conf)
<p>This function sets the password files, in a gnutls_srp_server_credentials_t structure.
Those password files hold usernames and verifiers and will be used for SRP authentication.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_srp_set_server_credentials_function</h4>
<p><a name="gnutls_005fsrp_005fset_005fserver_005fcredentials_005ffunction"></a>
<div class="defun">
— Function: void <b>gnutls_srp_set_server_credentials_function</b> (<var>gnutls_srp_server_credentials_t cred, gnutls_srp_server_credentials_function * func</var>)<var><a name="index-gnutls_005fsrp_005fset_005fserver_005fcredentials_005ffunction-217"></a></var><br>
<blockquote><p><var>cred</var>: is a <code>gnutls_srp_server_credentials_t</code> structure.
<p><var>func</var>: is the callback function
<p>This function can be used to set a callback to retrieve the user's SRP credentials.
The callback's function form is:
int (*callback)(gnutls_session_t, const char* username,
gnutls_datum_t* salt, gnutls_datum_t *verifier, gnutls_datum_t* g,
gnutls_datum_t* n);
<p><code>username</code> contains the actual username.
The <code>salt</code>, <code>verifier</code>, <code>generator</code> and <code>prime</code> must be filled
in using the <code>gnutls_malloc()</code>. For convenience <code>prime</code> and <code>generator</code>
may also be one of the static parameters defined in extra.h.
<p>In case the callback returned a negative number then gnutls will
assume that the username does not exist.
<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's parameters. In that case the callback must
return the special value (1).
<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></blockquote></div>
<h4 class="subheading">gnutls_srp_verifier</h4>
<p><a name="gnutls_005fsrp_005fverifier"></a>
<div class="defun">
— Function: int <b>gnutls_srp_verifier</b> (<var>const char * username, const char * password, const gnutls_datum_t * salt, const gnutls_datum_t * generator, const gnutls_datum_t * prime, gnutls_datum_t * res</var>)<var><a name="index-gnutls_005fsrp_005fverifier-218"></a></var><br>
<blockquote><p><var>username</var>: is the user's name
<p><var>password</var>: is the user's password
<p><var>salt</var>: should be some randomly generated bytes
<p><var>generator</var>: is the generator of the group
<p><var>prime</var>: is the group's prime
<p><var>res</var>: where the verifier will be stored.
<p>This function will create an SRP verifier, as specified in RFC2945.
The <code>prime</code> and <code>generator</code> should be one of the static parameters defined
in gnutls/extra.h or may be generated using the GCRYPT functions
<code>gcry_prime_generate()</code> and <code>gcry_prime_group_generator()</code>.
The verifier will be allocated with <code>malloc</code> and will be stored in <code>res</code> using
binary format.
</p></blockquote></div>
<h4 class="subheading">gnutls_strerror</h4>
<p><a name="gnutls_005fstrerror"></a>
<div class="defun">
— Function: const char * <b>gnutls_strerror</b> (<var>int error</var>)<var><a name="index-gnutls_005fstrerror-219"></a></var><br>
<blockquote><p><var>error</var>: is an error returned by a gnutls function. Error is always a negative value.
<p>This function is similar to <code>strerror()</code>. Differences: it accepts an error
number returned by a gnutls function; In case of an unknown error
a descriptive string is sent instead of NULL.
</p></blockquote></div>
<h4 class="subheading">gnutls_transport_get_ptr2</h4>
<p><a name="gnutls_005ftransport_005fget_005fptr2"></a>
<div class="defun">
— Function: void <b>gnutls_transport_get_ptr2</b> (<var>gnutls_session_t session, gnutls_transport_ptr_t * recv_ptr, gnutls_transport_ptr_t * send_ptr</var>)<var><a name="index-gnutls_005ftransport_005fget_005fptr2-220"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p><var>recv_ptr</var>: will hold the value for the pull function
<p><var>send_ptr</var>: will hold the value for the push function
<p>Used to get the arguments of the transport functions (like PUSH and
PULL). These should have been set using <code>gnutls_transport_set_ptr2()</code>.
</p></blockquote></div>
<h4 class="subheading">gnutls_transport_get_ptr</h4>
<p><a name="gnutls_005ftransport_005fget_005fptr"></a>
<div class="defun">
— Function: gnutls_transport_ptr_t <b>gnutls_transport_get_ptr</b> (<var>gnutls_session_t session</var>)<var><a name="index-gnutls_005ftransport_005fget_005fptr-221"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p>Used to get the first argument of the transport function (like PUSH and
PULL). This must have been set using <code>gnutls_transport_set_ptr()</code>.
</p></blockquote></div>
<h4 class="subheading">gnutls_transport_set_lowat</h4>
<p><a name="gnutls_005ftransport_005fset_005flowat"></a>
<div class="defun">
— Function: void <b>gnutls_transport_set_lowat</b> (<var>gnutls_session_t session, int num</var>)<var><a name="index-gnutls_005ftransport_005fset_005flowat-222"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p><var>num</var>: is the low water value.
<p>Used to set the lowat value in order for select to check
if there are pending data to socket buffer. Used only
if you have changed the default low water value (default is 1).
Normally you will not need that function.
This function is only useful if using berkeley style sockets.
Otherwise it must be called and set lowat to zero.
</p></blockquote></div>
<h4 class="subheading">gnutls_transport_set_ptr2</h4>
<p><a name="gnutls_005ftransport_005fset_005fptr2"></a>
<div class="defun">
— Function: void <b>gnutls_transport_set_ptr2</b> (<var>gnutls_session_t session, gnutls_transport_ptr_t recv_ptr, gnutls_transport_ptr_t send_ptr</var>)<var><a name="index-gnutls_005ftransport_005fset_005fptr2-223"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p><var>recv_ptr</var>: is the value for the pull function
<p><var>send_ptr</var>: is the value for the push function
<p>Used to set the first argument of the transport function (like PUSH and
PULL). In berkeley style sockets this function will set the connection
handle. With this function you can use two different pointers for
receiving and sending.
</p></blockquote></div>
<h4 class="subheading">gnutls_transport_set_ptr</h4>
<p><a name="gnutls_005ftransport_005fset_005fptr"></a>
<div class="defun">
— Function: void <b>gnutls_transport_set_ptr</b> (<var>gnutls_session_t session, gnutls_transport_ptr_t ptr</var>)<var><a name="index-gnutls_005ftransport_005fset_005fptr-224"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p><var>ptr</var>: is the value.
<p>Used to set the first argument of the transport function (like PUSH and
PULL). In berkeley style sockets this function will set the connection
handle.
</p></blockquote></div>
<h4 class="subheading">gnutls_transport_set_pull_function</h4>
<p><a name="gnutls_005ftransport_005fset_005fpull_005ffunction"></a>
<div class="defun">
— Function: void <b>gnutls_transport_set_pull_function</b> (<var>gnutls_session_t session, gnutls_pull_func pull_func</var>)<var><a name="index-gnutls_005ftransport_005fset_005fpull_005ffunction-225"></a></var><br>
<blockquote><p><var>session</var>: gnutls session
<p><var>pull_func</var>: a callback function similar to <code>read()</code>
<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.
<p>PULL_FUNC is of the form,
ssize_t (*gnutls_pull_func)(gnutls_transport_ptr_t, void*, size_t);
</p></blockquote></div>
<h4 class="subheading">gnutls_transport_set_push_function</h4>
<p><a name="gnutls_005ftransport_005fset_005fpush_005ffunction"></a>
<div class="defun">
— Function: void <b>gnutls_transport_set_push_function</b> (<var>gnutls_session_t session, gnutls_push_func push_func</var>)<var><a name="index-gnutls_005ftransport_005fset_005fpush_005ffunction-226"></a></var><br>
<blockquote><p><var>session</var>: gnutls session
<p><var>push_func</var>: a callback function similar to <code>write()</code>
<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.
<p>PUSH_FUNC is of the form,
ssize_t (*gnutls_push_func)(gnutls_transport_ptr_t, const void*, size_t);
</p></blockquote></div>
<div class="node">
<p><hr>
<a name="X.509-certificate-functions"></a>
<a name="X_002e509-certificate-functions"></a>
Next: <a rel="next" accesskey="n" href="#GnuTLS_002dextra-functions">GnuTLS-extra functions</a>,
Previous: <a rel="previous" accesskey="p" href="#Core-functions">Core functions</a>,
Up: <a rel="up" accesskey="u" href="#Function-reference">Function reference</a>
</div>
<h3 class="section">9.2 <acronym>X.509</acronym> certificate functions</h3>
<p><a name="sec_003ax509api"></a>
<a name="index-g_t_0040acronym_007bX_002e509_007d-Functions-227"></a>
The following functions are to be used for <acronym>X.509</acronym> certificate handling.
Their prototypes lie in <samp><span class="file">gnutls/x509.h</span></samp>.
<h4 class="subheading">gnutls_pkcs12_bag_decrypt</h4>
<p><a name="gnutls_005fpkcs12_005fbag_005fdecrypt"></a>
<div class="defun">
— Function: int <b>gnutls_pkcs12_bag_decrypt</b> (<var>gnutls_pkcs12_bag_t bag, const char * pass</var>)<var><a name="index-gnutls_005fpkcs12_005fbag_005fdecrypt-228"></a></var><br>
<blockquote><p><var>bag</var>: The bag
<p><var>pass</var>: The password used for encryption. This can only be ASCII.
<p>This function will decrypt the given encrypted bag and return 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_pkcs12_bag_deinit</h4>
<p><a name="gnutls_005fpkcs12_005fbag_005fdeinit"></a>
<div class="defun">
— Function: void <b>gnutls_pkcs12_bag_deinit</b> (<var>gnutls_pkcs12_bag_t bag</var>)<var><a name="index-gnutls_005fpkcs12_005fbag_005fdeinit-229"></a></var><br>
<blockquote><p><var>bag</var>: The structure to be initialized
<p>This function will deinitialize a PKCS12 Bag structure.
</p></blockquote></div>
<h4 class="subheading">gnutls_pkcs12_bag_encrypt</h4>
<p><a name="gnutls_005fpkcs12_005fbag_005fencrypt"></a>
<div class="defun">
— Function: int <b>gnutls_pkcs12_bag_encrypt</b> (<var>gnutls_pkcs12_bag_t bag, const char * pass, unsigned int flags</var>)<var><a name="index-gnutls_005fpkcs12_005fbag_005fencrypt-230"></a></var><br>
<blockquote><p><var>bag</var>: The bag
<p><var>pass</var>: The password used for encryption. This can only be ASCII.
<p><var>flags</var>: should be one of gnutls_pkcs_encrypt_flags_t elements bitwise or'd
<p>This function will encrypt the given bag and return 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_pkcs12_bag_get_count</h4>
<p><a name="gnutls_005fpkcs12_005fbag_005fget_005fcount"></a>
<div class="defun">
— Function: int <b>gnutls_pkcs12_bag_get_count</b> (<var>gnutls_pkcs12_bag_t bag</var>)<var><a name="index-gnutls_005fpkcs12_005fbag_005fget_005fcount-231"></a></var><br>
<blockquote><p><var>bag</var>: The bag
<p>This function will return the number of the elements withing the bag.
</p></blockquote></div>
<h4 class="subheading">gnutls_pkcs12_bag_get_data</h4>
<p><a name="gnutls_005fpkcs12_005fbag_005fget_005fdata"></a>
<div class="defun">
— Function: int <b>gnutls_pkcs12_bag_get_data</b> (<var>gnutls_pkcs12_bag_t bag, int indx, gnutls_datum_t * data</var>)<var><a name="index-gnutls_005fpkcs12_005fbag_005fget_005fdata-232"></a></var><br>
<blockquote><p><var>bag</var>: The bag
<p><var>indx</var>: The element of the bag to get the data from
<p><var>data</var>: where the bag's data will be. Should be treated as constant.
<p>This function will return the bag's data. The data is a constant
that is stored into the bag. Should not be accessed after the bag
is deleted.
<p>Returns 0 on success and a negative error code on error.
</p></blockquote></div>
<h4 class="subheading">gnutls_pkcs12_bag_get_friendly_name</h4>
<p><a name="gnutls_005fpkcs12_005fbag_005fget_005ffriendly_005fname"></a>
<div class="defun">
— Function: int <b>gnutls_pkcs12_bag_get_friendly_name</b> (<var>gnutls_pkcs12_bag_t bag, int indx, char ** name</var>)<var><a name="index-gnutls_005fpkcs12_005fbag_005fget_005ffriendly_005fname-233"></a></var><br>
<blockquote><p><var>bag</var>: The bag
<p><var>indx</var>: The bag's element to add the id
<p><var>name</var>: will hold a pointer to the name (to be treated as const)
<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>Returns 0 on success, or a negative value on error.
</p></blockquote></div>
<h4 class="subheading">gnutls_pkcs12_bag_get_key_id</h4>
<p><a name="gnutls_005fpkcs12_005fbag_005fget_005fkey_005fid"></a>
<div class="defun">
— Function: int <b>gnutls_pkcs12_bag_get_key_id</b> (<var>gnutls_pkcs12_bag_t bag, int indx, gnutls_datum_t * id</var>)<var><a name="index-gnutls_005fpkcs12_005fbag_005fget_005fkey_005fid-234"></a></var><br>
<blockquote><p><var>bag</var>: The bag
<p><var>indx</var>: The bag's element to add the id
<p><var>id</var>: where the ID will be copied (to be treated as const)
<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>Returns 0 on success, or a negative value on error.
</p></blockquote></div>
<h4 class="subheading">gnutls_pkcs12_bag_get_type</h4>
<p><a name="gnutls_005fpkcs12_005fbag_005fget_005ftype"></a>
<div class="defun">
— Function: gnutls_pkcs12_bag_type_t <b>gnutls_pkcs12_bag_get_type</b> (<var>gnutls_pkcs12_bag_t bag, int indx</var>)<var><a name="index-gnutls_005fpkcs12_005fbag_005fget_005ftype-235"></a></var><br>
<blockquote><p><var>bag</var>: The bag
<p><var>indx</var>: The element of the bag to get the type
<p>This function will return the bag's type. One of the gnutls_pkcs12_bag_type_t
enumerations.
</p></blockquote></div>
<h4 class="subheading">gnutls_pkcs12_bag_init</h4>
<p><a name="gnutls_005fpkcs12_005fbag_005finit"></a>
<div class="defun">
— Function: int <b>gnutls_pkcs12_bag_init</b> (<var>gnutls_pkcs12_bag_t * bag</var>)<var><a name="index-gnutls_005fpkcs12_005fbag_005finit-236"></a></var><br>
<blockquote><p><var>bag</var>: The structure to be initialized
<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>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_pkcs12_bag_set_crl</h4>
<p><a name="gnutls_005fpkcs12_005fbag_005fset_005fcrl"></a>
<div class="defun">
— Function: int <b>gnutls_pkcs12_bag_set_crl</b> (<var>gnutls_pkcs12_bag_t bag, gnutls_x509_crl_t crl</var>)<var><a name="index-gnutls_005fpkcs12_005fbag_005fset_005fcrl-237"></a></var><br>
<blockquote><p><var>bag</var>: The bag
<p><var>crl</var>: the CRL to be copied.
<p>This function will insert the given CRL into the
bag. This is just a wrapper over <code>gnutls_pkcs12_bag_set_data()</code>.
<p>Returns the index of the added bag on success, or a negative
value on failure.
</p></blockquote></div>
<h4 class="subheading">gnutls_pkcs12_bag_set_crt</h4>
<p><a name="gnutls_005fpkcs12_005fbag_005fset_005fcrt"></a>
<div class="defun">
— Function: int <b>gnutls_pkcs12_bag_set_crt</b> (<var>gnutls_pkcs12_bag_t bag, gnutls_x509_crt_t crt</var>)<var><a name="index-gnutls_005fpkcs12_005fbag_005fset_005fcrt-238"></a></var><br>
<blockquote><p><var>bag</var>: The bag
<p><var>crt</var>: the certificate to be copied.
<p>This function will insert the given certificate into the
bag. This is just a wrapper over <code>gnutls_pkcs12_bag_set_data()</code>.
<p>Returns the index of the added bag on success, or a negative
value on failure.
</p></blockquote></div>
<h4 class="subheading">gnutls_pkcs12_bag_set_data</h4>
<p><a name="gnutls_005fpkcs12_005fbag_005fset_005fdata"></a>
<div class="defun">
— Function: int <b>gnutls_pkcs12_bag_set_data</b> (<var>gnutls_pkcs12_bag_t bag, gnutls_pkcs12_bag_type_t type, const gnutls_datum_t * data</var>)<var><a name="index-gnutls_005fpkcs12_005fbag_005fset_005fdata-239"></a></var><br>
<blockquote><p><var>bag</var>: The bag
<p><var>type</var>: The data's type
<p><var>data</var>: the data to be copied.
<p>This function will insert the given data of the given type into the
bag.
<p>Returns the index of the added bag on success, or a negative
value on error.
</p></blockquote></div>
<h4 class="subheading">gnutls_pkcs12_bag_set_friendly_name</h4>
<p><a name="gnutls_005fpkcs12_005fbag_005fset_005ffriendly_005fname"></a>
<div class="defun">
— Function: int <b>gnutls_pkcs12_bag_set_friendly_name</b> (<var>gnutls_pkcs12_bag_t bag, int indx, const char * name</var>)<var><a name="index-gnutls_005fpkcs12_005fbag_005fset_005ffriendly_005fname-240"></a></var><br>
<blockquote><p><var>bag</var>: The bag
<p><var>indx</var>: The bag's element to add the id
<p><var>name</var>: the name
<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 'Friendly name' bag attribute,
which is usually used to set a user name to the local private key and the certificate pair.
<p>Returns 0 on success, or a negative value on error.
</p></blockquote></div>
<h4 class="subheading">gnutls_pkcs12_bag_set_key_id</h4>
<p><a name="gnutls_005fpkcs12_005fbag_005fset_005fkey_005fid"></a>
<div class="defun">
— Function: int <b>gnutls_pkcs12_bag_set_key_id</b> (<var>gnutls_pkcs12_bag_t bag, int indx, const gnutls_datum_t * id</var>)<var><a name="index-gnutls_005fpkcs12_005fbag_005fset_005fkey_005fid-241"></a></var><br>
<blockquote><p><var>bag</var>: The bag
<p><var>indx</var>: The bag's element to add the id
<p><var>id</var>: the ID
<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 'Local key identifier' bag attribute,
which is usually used to distinguish the local private key and the certificate pair.
<p>Returns 0 on success, or a negative value on error.
</p></blockquote></div>
<h4 class="subheading">gnutls_pkcs12_deinit</h4>
<p><a name="gnutls_005fpkcs12_005fdeinit"></a>
<div class="defun">
— Function: void <b>gnutls_pkcs12_deinit</b> (<var>gnutls_pkcs12_t pkcs12</var>)<var><a name="index-gnutls_005fpkcs12_005fdeinit-242"></a></var><br>
<blockquote><p><var>pkcs12</var>: The structure to be initialized
<p>This function will deinitialize a PKCS12 structure.
</p></blockquote></div>
<h4 class="subheading">gnutls_pkcs12_export</h4>
<p><a name="gnutls_005fpkcs12_005fexport"></a>
<div class="defun">
— Function: int <b>gnutls_pkcs12_export</b> (<var>gnutls_pkcs12_t pkcs12, gnutls_x509_crt_fmt_t format, void * output_data, size_t * output_data_size</var>)<var><a name="index-gnutls_005fpkcs12_005fexport-243"></a></var><br>
<blockquote><p><var>pkcs12</var>: Holds the pkcs12 structure
<p><var>format</var>: the format of output params. One of PEM or DER.
<p><var>output_data</var>: will contain a structure PEM or DER encoded
<p><var>output_data_size</var>: holds the size of output_data (and will be
replaced by the actual size of parameters)
<p>This function will export the pkcs12 structure to DER or PEM format.
<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>If the structure is PEM encoded, it will have a header
of "BEGIN PKCS12".
<p><strong>Return value:</strong> In case of failure a negative value will be
returned, and 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_pkcs12_generate_mac</h4>
<p><a name="gnutls_005fpkcs12_005fgenerate_005fmac"></a>
<div class="defun">
— Function: int <b>gnutls_pkcs12_generate_mac</b> (<var>gnutls_pkcs12_t pkcs12, const char * pass</var>)<var><a name="index-gnutls_005fpkcs12_005fgenerate_005fmac-244"></a></var><br>
<blockquote><p><var>pkcs12</var>: should contain a gnutls_pkcs12_t structure
<p><var>pass</var>: The password for the MAC
<p>This function will generate a MAC for the PKCS12 structure.
Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_pkcs12_get_bag</h4>
<p><a name="gnutls_005fpkcs12_005fget_005fbag"></a>
<div class="defun">
— Function: int <b>gnutls_pkcs12_get_bag</b> (<var>gnutls_pkcs12_t pkcs12, int indx, gnutls_pkcs12_bag_t bag</var>)<var><a name="index-gnutls_005fpkcs12_005fget_005fbag-245"></a></var><br>
<blockquote><p><var>pkcs12</var>: should contain a gnutls_pkcs12_t structure
<p><var>indx</var>: contains the index of the bag to extract
<p><var>bag</var>: An initialized bag, where the contents of the bag will be copied
<p>This function will return a Bag from the PKCS12 structure.
Returns 0 on success.
<p>After the last Bag has been read GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE
will be returned.
</p></blockquote></div>
<h4 class="subheading">gnutls_pkcs12_import</h4>
<p><a name="gnutls_005fpkcs12_005fimport"></a>
<div class="defun">
— Function: int <b>gnutls_pkcs12_import</b> (<var>gnutls_pkcs12_t pkcs12, const gnutls_datum_t * data, gnutls_x509_crt_fmt_t format, unsigned int flags</var>)<var><a name="index-gnutls_005fpkcs12_005fimport-246"></a></var><br>
<blockquote><p><var>pkcs12</var>: The structure to store the parsed PKCS12.
<p><var>data</var>: The DER or PEM encoded PKCS12.
<p><var>format</var>: One of DER or PEM
<p><var>flags</var>: an ORed sequence of gnutls_privkey_pkcs8_flags
<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 'pkcs12'.
<p>If the PKCS12 is PEM encoded it should have a header of "PKCS12".
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_pkcs12_init</h4>
<p><a name="gnutls_005fpkcs12_005finit"></a>
<div class="defun">
— Function: int <b>gnutls_pkcs12_init</b> (<var>gnutls_pkcs12_t * pkcs12</var>)<var><a name="index-gnutls_005fpkcs12_005finit-247"></a></var><br>
<blockquote><p><var>pkcs12</var>: The structure to be initialized
<p>This function will initialize a PKCS12 structure. PKCS12 structures
usually contain lists of X.509 Certificates and X.509 Certificate
revocation lists.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_pkcs12_set_bag</h4>
<p><a name="gnutls_005fpkcs12_005fset_005fbag"></a>
<div class="defun">
— Function: int <b>gnutls_pkcs12_set_bag</b> (<var>gnutls_pkcs12_t pkcs12, gnutls_pkcs12_bag_t bag</var>)<var><a name="index-gnutls_005fpkcs12_005fset_005fbag-248"></a></var><br>
<blockquote><p><var>pkcs12</var>: should contain a gnutls_pkcs12_t structure
<p><var>bag</var>: An initialized bag
<p>This function will insert a Bag into the PKCS12 structure.
Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_pkcs12_verify_mac</h4>
<p><a name="gnutls_005fpkcs12_005fverify_005fmac"></a>
<div class="defun">
— Function: int <b>gnutls_pkcs12_verify_mac</b> (<var>gnutls_pkcs12_t pkcs12, const char * pass</var>)<var><a name="index-gnutls_005fpkcs12_005fverify_005fmac-249"></a></var><br>
<blockquote><p><var>pkcs12</var>: should contain a gnutls_pkcs12_t structure
<p><var>pass</var>: The password for the MAC
<p>This function will verify the MAC for the PKCS12 structure.
Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_pkcs7_deinit</h4>
<p><a name="gnutls_005fpkcs7_005fdeinit"></a>
<div class="defun">
— Function: void <b>gnutls_pkcs7_deinit</b> (<var>gnutls_pkcs7_t pkcs7</var>)<var><a name="index-gnutls_005fpkcs7_005fdeinit-250"></a></var><br>
<blockquote><p><var>pkcs7</var>: The structure to be initialized
<p>This function will deinitialize a PKCS7 structure.
</p></blockquote></div>
<h4 class="subheading">gnutls_pkcs7_delete_crl</h4>
<p><a name="gnutls_005fpkcs7_005fdelete_005fcrl"></a>
<div class="defun">
— Function: int <b>gnutls_pkcs7_delete_crl</b> (<var>gnutls_pkcs7_t pkcs7, int indx</var>)<var><a name="index-gnutls_005fpkcs7_005fdelete_005fcrl-251"></a></var><br>
<blockquote><p><var>indx</var>: the index of the crl to delete
<p>This function will delete a crl from a PKCS7 or RFC2630 crl set.
Index starts from 0. Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_pkcs7_delete_crt</h4>
<p><a name="gnutls_005fpkcs7_005fdelete_005fcrt"></a>
<div class="defun">
— Function: int <b>gnutls_pkcs7_delete_crt</b> (<var>gnutls_pkcs7_t pkcs7, int indx</var>)<var><a name="index-gnutls_005fpkcs7_005fdelete_005fcrt-252"></a></var><br>
<blockquote><p><var>indx</var>: the index of the certificate to delete
<p>This function will delete a certificate from a PKCS7 or RFC2630 certificate set.
Index starts from 0. Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_pkcs7_export</h4>
<p><a name="gnutls_005fpkcs7_005fexport"></a>
<div class="defun">
— Function: int <b>gnutls_pkcs7_export</b> (<var>gnutls_pkcs7_t pkcs7, gnutls_x509_crt_fmt_t format, void * output_data, size_t * output_data_size</var>)<var><a name="index-gnutls_005fpkcs7_005fexport-253"></a></var><br>
<blockquote><p><var>pkcs7</var>: Holds the pkcs7 structure
<p><var>format</var>: the format of output params. One of PEM or DER.
<p><var>output_data</var>: will contain a structure PEM or DER encoded
<p><var>output_data_size</var>: holds the size of output_data (and will be
replaced by the actual size of parameters)
<p>This function will export the pkcs7 structure to DER or PEM format.
<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>If the structure is PEM encoded, it will have a header
of "BEGIN PKCS7".
<p><strong>Return value:</strong> In case of failure a negative value will be
returned, and 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_pkcs7_get_crl_count</h4>
<p><a name="gnutls_005fpkcs7_005fget_005fcrl_005fcount"></a>
<div class="defun">
— Function: int <b>gnutls_pkcs7_get_crl_count</b> (<var>gnutls_pkcs7_t pkcs7</var>)<var><a name="index-gnutls_005fpkcs7_005fget_005fcrl_005fcount-254"></a></var><br>
<blockquote><p>This function will return the number of certifcates in the PKCS7 or
RFC2630 crl set.
<p>Returns a negative value on failure.
</p></blockquote></div>
<h4 class="subheading">gnutls_pkcs7_get_crl_raw</h4>
<p><a name="gnutls_005fpkcs7_005fget_005fcrl_005fraw"></a>
<div class="defun">
— Function: int <b>gnutls_pkcs7_get_crl_raw</b> (<var>gnutls_pkcs7_t pkcs7, int indx, void * crl, size_t * crl_size</var>)<var><a name="index-gnutls_005fpkcs7_005fget_005fcrl_005fraw-255"></a></var><br>
<blockquote><p><var>indx</var>: contains the index of the crl to extract
<p><var>crl</var>: the contents of the crl will be copied there (may be null)
<p><var>crl_size</var>: should hold the size of the crl
<p>This function will return a crl of the PKCS7 or RFC2630 crl set.
Returns 0 on success. If the provided buffer is not long enough,
then <code>crl_size</code> is updated and GNUTLS_E_SHORT_MEMORY_BUFFER is returned.
<p>After the last crl has been read GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE
will be returned.
</p></blockquote></div>
<h4 class="subheading">gnutls_pkcs7_get_crt_count</h4>
<p><a name="gnutls_005fpkcs7_005fget_005fcrt_005fcount"></a>
<div class="defun">
— Function: int <b>gnutls_pkcs7_get_crt_count</b> (<var>gnutls_pkcs7_t pkcs7</var>)<var><a name="index-gnutls_005fpkcs7_005fget_005fcrt_005fcount-256"></a></var><br>
<blockquote><p>This function will return the number of certifcates in the PKCS7 or
RFC2630 certificate set.
<p>Returns a negative value on failure.
</p></blockquote></div>
<h4 class="subheading">gnutls_pkcs7_get_crt_raw</h4>
<p><a name="gnutls_005fpkcs7_005fget_005fcrt_005fraw"></a>
<div class="defun">
— Function: int <b>gnutls_pkcs7_get_crt_raw</b> (<var>gnutls_pkcs7_t pkcs7, int indx, void * certificate, size_t * certificate_size</var>)<var><a name="index-gnutls_005fpkcs7_005fget_005fcrt_005fraw-257"></a></var><br>
<blockquote><p><var>indx</var>: contains the index of the certificate to extract
<p><var>certificate</var>: the contents of the certificate will be copied there (may be null)
<p><var>certificate_size</var>: should hold the size of the certificate
<p>This function will return a certificate of the PKCS7 or RFC2630 certificate set.
Returns 0 on success. If the provided buffer is not long enough,
then <code>certificate_size</code> is updated and GNUTLS_E_SHORT_MEMORY_BUFFER is returned.
<p>After the last certificate has been read GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE
will be returned.
</p></blockquote></div>
<h4 class="subheading">gnutls_pkcs7_import</h4>
<p><a name="gnutls_005fpkcs7_005fimport"></a>
<div class="defun">
— Function: int <b>gnutls_pkcs7_import</b> (<var>gnutls_pkcs7_t pkcs7, const gnutls_datum_t * data, gnutls_x509_crt_fmt_t format</var>)<var><a name="index-gnutls_005fpkcs7_005fimport-258"></a></var><br>
<blockquote><p><var>pkcs7</var>: The structure to store the parsed PKCS7.
<p><var>data</var>: The DER or PEM encoded PKCS7.
<p><var>format</var>: One of DER or PEM
<p>This function will convert the given DER or PEM encoded PKCS7
to the native gnutls_pkcs7_t format. The output will be stored in 'pkcs7'.
<p>If the PKCS7 is PEM encoded it should have a header of "PKCS7".
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_pkcs7_init</h4>
<p><a name="gnutls_005fpkcs7_005finit"></a>
<div class="defun">
— Function: int <b>gnutls_pkcs7_init</b> (<var>gnutls_pkcs7_t * pkcs7</var>)<var><a name="index-gnutls_005fpkcs7_005finit-259"></a></var><br>
<blockquote><p><var>pkcs7</var>: The structure to be initialized
<p>This function will initialize a PKCS7 structure. PKCS7 structures
usually contain lists of X.509 Certificates and X.509 Certificate
revocation lists.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_pkcs7_set_crl_raw</h4>
<p><a name="gnutls_005fpkcs7_005fset_005fcrl_005fraw"></a>
<div class="defun">
— Function: int <b>gnutls_pkcs7_set_crl_raw</b> (<var>gnutls_pkcs7_t pkcs7, const gnutls_datum_t * crl</var>)<var><a name="index-gnutls_005fpkcs7_005fset_005fcrl_005fraw-260"></a></var><br>
<blockquote><p><var>crl</var>: the DER encoded crl to be added
<p>This function will add a crl to the PKCS7 or RFC2630 crl set.
Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_pkcs7_set_crl</h4>
<p><a name="gnutls_005fpkcs7_005fset_005fcrl"></a>
<div class="defun">
— Function: int <b>gnutls_pkcs7_set_crl</b> (<var>gnutls_pkcs7_t pkcs7, gnutls_x509_crl_t crl</var>)<var><a name="index-gnutls_005fpkcs7_005fset_005fcrl-261"></a></var><br>
<blockquote><p><var>crl</var>: the DER encoded crl to be added
<p>This function will add a parsed crl to the PKCS7 or RFC2630 crl set.
Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_pkcs7_set_crt_raw</h4>
<p><a name="gnutls_005fpkcs7_005fset_005fcrt_005fraw"></a>
<div class="defun">
— Function: int <b>gnutls_pkcs7_set_crt_raw</b> (<var>gnutls_pkcs7_t pkcs7, const gnutls_datum_t * crt</var>)<var><a name="index-gnutls_005fpkcs7_005fset_005fcrt_005fraw-262"></a></var><br>
<blockquote><p><var>crt</var>: the DER encoded certificate to be added
<p>This function will add a certificate to the PKCS7 or RFC2630 certificate set.
Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_pkcs7_set_crt</h4>
<p><a name="gnutls_005fpkcs7_005fset_005fcrt"></a>
<div class="defun">
— Function: int <b>gnutls_pkcs7_set_crt</b> (<var>gnutls_pkcs7_t pkcs7, gnutls_x509_crt_t crt</var>)<var><a name="index-gnutls_005fpkcs7_005fset_005fcrt-263"></a></var><br>
<blockquote><p><var>crt</var>: the certificate to be copied.
<p>This function will add a parsed certificate to the PKCS7 or RFC2630 certificate set.
This is a wrapper function over <code>gnutls_pkcs7_set_crt_raw()</code> .
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crl_check_issuer</h4>
<p><a name="gnutls_005fx509_005fcrl_005fcheck_005fissuer"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crl_check_issuer</b> (<var>gnutls_x509_crl_t cert, gnutls_x509_crt_t issuer</var>)<var><a name="index-gnutls_005fx509_005fcrl_005fcheck_005fissuer-264"></a></var><br>
<blockquote><p><var>issuer</var>: is the certificate of a possible issuer
<p>This function will check if the given CRL was issued by the
given issuer certificate. It will return true (1) if the given CRL was issued
by the given issuer, and false (0) if not.
<p>A negative value is returned in case of an error.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crl_deinit</h4>
<p><a name="gnutls_005fx509_005fcrl_005fdeinit"></a>
<div class="defun">
— Function: void <b>gnutls_x509_crl_deinit</b> (<var>gnutls_x509_crl_t crl</var>)<var><a name="index-gnutls_005fx509_005fcrl_005fdeinit-265"></a></var><br>
<blockquote><p><var>crl</var>: The structure to be initialized
<p>This function will deinitialize a CRL structure.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crl_export</h4>
<p><a name="gnutls_005fx509_005fcrl_005fexport"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crl_export</b> (<var>gnutls_x509_crl_t crl, gnutls_x509_crt_fmt_t format, void * output_data, size_t * output_data_size</var>)<var><a name="index-gnutls_005fx509_005fcrl_005fexport-266"></a></var><br>
<blockquote><p><var>crl</var>: Holds the revocation list
<p><var>format</var>: the format of output params. One of PEM or DER.
<p><var>output_data</var>: will contain a private key PEM or DER encoded
<p><var>output_data_size</var>: holds the size of output_data (and will be replaced by the actual size of parameters)
<p>This function will export the revocation list to DER or PEM format.
<p>If the buffer provided is not long enough to hold the output, then
GNUTLS_E_SHORT_MEMORY_BUFFER will be returned.
<p>If the structure is PEM encoded, it will have a header
of "BEGIN X509 CRL".
<p>Returns 0 on success, and a negative value on failure.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crl_get_crt_count</h4>
<p><a name="gnutls_005fx509_005fcrl_005fget_005fcrt_005fcount"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crl_get_crt_count</b> (<var>gnutls_x509_crl_t crl</var>)<var><a name="index-gnutls_005fx509_005fcrl_005fget_005fcrt_005fcount-267"></a></var><br>
<blockquote><p><var>crl</var>: should contain a gnutls_x509_crl_t structure
<p>This function will return the number of revoked certificates in the
given CRL.
<p>Returns a negative value on failure.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crl_get_crt_serial</h4>
<p><a name="gnutls_005fx509_005fcrl_005fget_005fcrt_005fserial"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crl_get_crt_serial</b> (<var>gnutls_x509_crl_t crl, int indx, unsigned char * serial, size_t * serial_size, time_t * t</var>)<var><a name="index-gnutls_005fx509_005fcrl_005fget_005fcrt_005fserial-268"></a></var><br>
<blockquote><p><var>crl</var>: should contain a gnutls_x509_crl_t structure
<p><var>indx</var>: the index of the certificate to extract (starting from 0)
<p><var>serial</var>: where the serial number will be copied
<p><var>serial_size</var>: initially holds the size of serial
<p><var>t</var>: if non null, will hold the time this certificate was revoked
<p>This function will return the serial number of the specified, by
the index, revoked certificate.
<p>Returns a negative value on failure.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crl_get_dn_oid</h4>
<p><a name="gnutls_005fx509_005fcrl_005fget_005fdn_005foid"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crl_get_dn_oid</b> (<var>gnutls_x509_crl_t crl, int indx, void * oid, size_t * sizeof_oid</var>)<var><a name="index-gnutls_005fx509_005fcrl_005fget_005fdn_005foid-269"></a></var><br>
<blockquote><p><var>crl</var>: should contain a gnutls_x509_crl_t structure
<p><var>indx</var>: Specifies which DN OID to send. Use zero to get the first one.
<p><var>oid</var>: a pointer to a structure to hold the name (may be null)
<p><var>sizeof_oid</var>: initially holds the size of 'oid'
<p>This function will extract the requested OID of the name of the CRL issuer, specified
by the given index.
<p>If oid is null then only the size will be filled.
<p>Returns GNUTLS_E_SHORT_MEMORY_BUFFER 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></blockquote></div>
<h4 class="subheading">gnutls_x509_crl_get_issuer_dn_by_oid</h4>
<p><a name="gnutls_005fx509_005fcrl_005fget_005fissuer_005fdn_005fby_005foid"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crl_get_issuer_dn_by_oid</b> (<var>gnutls_x509_crl_t crl, const char * oid, int indx, unsigned int raw_flag, void * buf, size_t * sizeof_buf</var>)<var><a name="index-gnutls_005fx509_005fcrl_005fget_005fissuer_005fdn_005fby_005foid-270"></a></var><br>
<blockquote><p><var>crl</var>: should contain a gnutls_x509_crl_t structure
<p><var>oid</var>: holds an Object Identified in null terminated string
<p><var>indx</var>: In case multiple same OIDs exist in the RDN, this specifies which to send. Use zero to get the first one.
<p><var>raw_flag</var>: If non zero returns the raw DER data of the DN part.
<p><var>buf</var>: a pointer to a structure to hold the peer's name (may be null)
<p><var>sizeof_buf</var>: initially holds the size of <code>buf</code>
<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 RFC2253. The output
string will be ASCII or UTF-8 encoded, depending on the certificate data.
<p>Some helper macros with popular OIDs can be found in gnutls/x509.h
If raw flag is zero, this function will only return known OIDs as text. Other OIDs
will be DER encoded, as described in RFC2253 – in hex format with a '\#' prefix.
You can check about known OIDs using <code>gnutls_x509_dn_oid_known()</code>.
<p>If buf is null then only the size will be filled.
<p>Returns GNUTLS_E_SHORT_MEMORY_BUFFER 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></blockquote></div>
<h4 class="subheading">gnutls_x509_crl_get_issuer_dn</h4>
<p><a name="gnutls_005fx509_005fcrl_005fget_005fissuer_005fdn"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crl_get_issuer_dn</b> (<var>gnutls_x509_crl_t crl, char * buf, size_t * sizeof_buf</var>)<var><a name="index-gnutls_005fx509_005fcrl_005fget_005fissuer_005fdn-271"></a></var><br>
<blockquote><p><var>crl</var>: should contain a gnutls_x509_crl_t structure
<p><var>buf</var>: a pointer to a structure to hold the peer's name (may be null)
<p><var>sizeof_buf</var>: initially holds the size of <code>buf</code>
<p>This function will copy the name of the CRL issuer in the provided buffer. The name
will be in the form "C=xxxx,O=yyyy,CN=zzzz" as described in RFC2253. The output
string will be ASCII or UTF-8 encoded, depending on the certificate data.
<p>If buf is null then only the size will be filled.
<p>Returns GNUTLS_E_SHORT_MEMORY_BUFFER 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></blockquote></div>
<h4 class="subheading">gnutls_x509_crl_get_next_update</h4>
<p><a name="gnutls_005fx509_005fcrl_005fget_005fnext_005fupdate"></a>
<div class="defun">
— Function: time_t <b>gnutls_x509_crl_get_next_update</b> (<var>gnutls_x509_crl_t crl</var>)<var><a name="index-gnutls_005fx509_005fcrl_005fget_005fnext_005fupdate-272"></a></var><br>
<blockquote><p><var>crl</var>: should contain a gnutls_x509_crl_t structure
<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>Returns (time_t)-1 on error.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crl_get_signature_algorithm</h4>
<p><a name="gnutls_005fx509_005fcrl_005fget_005fsignature_005falgorithm"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crl_get_signature_algorithm</b> (<var>gnutls_x509_crl_t crl</var>)<var><a name="index-gnutls_005fx509_005fcrl_005fget_005fsignature_005falgorithm-273"></a></var><br>
<blockquote><p><var>crl</var>: should contain a gnutls_x509_crl_t structure
<p>This function will return a value of the gnutls_sign_algorithm_t enumeration that
is the signature algorithm.
<p>Returns a negative value on error.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crl_get_this_update</h4>
<p><a name="gnutls_005fx509_005fcrl_005fget_005fthis_005fupdate"></a>
<div class="defun">
— Function: time_t <b>gnutls_x509_crl_get_this_update</b> (<var>gnutls_x509_crl_t crl</var>)<var><a name="index-gnutls_005fx509_005fcrl_005fget_005fthis_005fupdate-274"></a></var><br>
<blockquote><p><var>crl</var>: should contain a gnutls_x509_crl_t structure
<p>This function will return the time this CRL was issued.
<p>Returns (time_t)-1 on error.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crl_get_version</h4>
<p><a name="gnutls_005fx509_005fcrl_005fget_005fversion"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crl_get_version</b> (<var>gnutls_x509_crl_t crl</var>)<var><a name="index-gnutls_005fx509_005fcrl_005fget_005fversion-275"></a></var><br>
<blockquote><p><var>crl</var>: should contain a gnutls_x509_crl_t structure
<p>This function will return the version of the specified CRL.
<p>Returns a negative value on error.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crl_import</h4>
<p><a name="gnutls_005fx509_005fcrl_005fimport"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crl_import</b> (<var>gnutls_x509_crl_t crl, const gnutls_datum_t * data, gnutls_x509_crt_fmt_t format</var>)<var><a name="index-gnutls_005fx509_005fcrl_005fimport-276"></a></var><br>
<blockquote><p><var>crl</var>: The structure to store the parsed CRL.
<p><var>data</var>: The DER or PEM encoded CRL.
<p><var>format</var>: One of DER or PEM
<p>This function will convert the given DER or PEM encoded CRL
to the native gnutls_x509_crl_t format. The output will be stored in 'crl'.
<p>If the CRL is PEM encoded it should have a header of "X509 CRL".
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crl_init</h4>
<p><a name="gnutls_005fx509_005fcrl_005finit"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crl_init</b> (<var>gnutls_x509_crl_t * crl</var>)<var><a name="index-gnutls_005fx509_005fcrl_005finit-277"></a></var><br>
<blockquote><p><var>crl</var>: The structure to be initialized
<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's private key.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crl_set_crt_serial</h4>
<p><a name="gnutls_005fx509_005fcrl_005fset_005fcrt_005fserial"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crl_set_crt_serial</b> (<var>gnutls_x509_crl_t crl, const void * serial, size_t serial_size, time_t revocation_time</var>)<var><a name="index-gnutls_005fx509_005fcrl_005fset_005fcrt_005fserial-278"></a></var><br>
<blockquote><p><var>crl</var>: should contain a gnutls_x509_crl_t structure
<p><var>serial</var>: The revoked certificate's serial number
<p><var>serial_size</var>: Holds the size of the serial field.
<p><var>revocation_time</var>: The time this certificate was revoked
<p>This function will set a revoked certificate's serial number to the CRL.
<p>Returns 0 on success, or a negative value in case of an error.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crl_set_crt</h4>
<p><a name="gnutls_005fx509_005fcrl_005fset_005fcrt"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crl_set_crt</b> (<var>gnutls_x509_crl_t crl, gnutls_x509_crt_t crt, time_t revocation_time</var>)<var><a name="index-gnutls_005fx509_005fcrl_005fset_005fcrt-279"></a></var><br>
<blockquote><p><var>crl</var>: should contain a gnutls_x509_crl_t structure
<p><var>crt</var>: should contain a gnutls_x509_crt_t structure with the revoked certificate
<p><var>revocation_time</var>: The time this certificate was revoked
<p>This function will set a revoked certificate's serial number to the CRL.
<p>Returns 0 on success, or a negative value in case of an error.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crl_set_next_update</h4>
<p><a name="gnutls_005fx509_005fcrl_005fset_005fnext_005fupdate"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crl_set_next_update</b> (<var>gnutls_x509_crl_t crl, time_t exp_time</var>)<var><a name="index-gnutls_005fx509_005fcrl_005fset_005fnext_005fupdate-280"></a></var><br>
<blockquote><p><var>crl</var>: should contain a gnutls_x509_crl_t structure
<p><var>exp_time</var>: The actual time
<p>This function will set the time this CRL will be updated.
<p>Returns 0 on success, or a negative value in case of an error.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crl_set_this_update</h4>
<p><a name="gnutls_005fx509_005fcrl_005fset_005fthis_005fupdate"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crl_set_this_update</b> (<var>gnutls_x509_crl_t crl, time_t act_time</var>)<var><a name="index-gnutls_005fx509_005fcrl_005fset_005fthis_005fupdate-281"></a></var><br>
<blockquote><p><var>crl</var>: should contain a gnutls_x509_crl_t structure
<p><var>act_time</var>: The actual time
<p>This function will set the time this CRL was issued.
<p>Returns 0 on success, or a negative value in case of an error.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crl_set_version</h4>
<p><a name="gnutls_005fx509_005fcrl_005fset_005fversion"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crl_set_version</b> (<var>gnutls_x509_crl_t crl, unsigned int version</var>)<var><a name="index-gnutls_005fx509_005fcrl_005fset_005fversion-282"></a></var><br>
<blockquote><p><var>crl</var>: should contain a gnutls_x509_crl_t structure
<p><var>version</var>: holds the version number. For CRLv1 crls must be 1.
<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>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crl_sign2</h4>
<p><a name="gnutls_005fx509_005fcrl_005fsign2"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crl_sign2</b> (<var>gnutls_x509_crl_t crl, gnutls_x509_crt_t issuer, gnutls_x509_privkey_t issuer_key, gnutls_digest_algorithm_t dig, unsigned int flags</var>)<var><a name="index-gnutls_005fx509_005fcrl_005fsign2-283"></a></var><br>
<blockquote><p><var>crl</var>: should contain a gnutls_x509_crl_t structure
<p><var>issuer</var>: is the certificate of the certificate issuer
<p><var>issuer_key</var>: holds the issuer's private key
<p><var>dig</var>: The message digest to use. GNUTLS_DIG_SHA1 is the safe choice unless you know what you're doing.
<p><var>flags</var>: must be 0
<p>This function will sign the CRL with the issuer's private key, and
will copy the issuer's information into the CRL.
<p>This must be the last step in a certificate CRL since all
the previously set parameters are now signed.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crl_sign</h4>
<p><a name="gnutls_005fx509_005fcrl_005fsign"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crl_sign</b> (<var>gnutls_x509_crl_t crl, gnutls_x509_crt_t issuer, gnutls_x509_privkey_t issuer_key</var>)<var><a name="index-gnutls_005fx509_005fcrl_005fsign-284"></a></var><br>
<blockquote><p><var>crl</var>: should contain a gnutls_x509_crl_t structure
<p><var>issuer</var>: is the certificate of the certificate issuer
<p><var>issuer_key</var>: holds the issuer's private key
<p>This function is the same a <code>gnutls_x509_crl_sign2()</code> with no flags, and
SHA1 as the hash algorithm.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crl_verify</h4>
<p><a name="gnutls_005fx509_005fcrl_005fverify"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crl_verify</b> (<var>gnutls_x509_crl_t crl, const gnutls_x509_crt_t * CA_list, int CA_list_length, unsigned int flags, unsigned int * verify</var>)<var><a name="index-gnutls_005fx509_005fcrl_005fverify-285"></a></var><br>
<blockquote><p><var>crl</var>: is the crl to be verified
<p><var>CA_list</var>: is a certificate list that is considered to be trusted one
<p><var>CA_list_length</var>: holds the number of CA certificates in CA_list
<p><var>flags</var>: Flags that may be used to change the verification algorithm. Use OR of the gnutls_certificate_verify_flags enumerations.
<p><var>verify</var>: will hold the crl verification output.
<p>This function will try to verify the given crl and return its status.
See <code>gnutls_x509_crt_list_verify()</code> for a detailed description of
return values.
<p>Returns 0 on success and a negative value in case of an error.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crq_deinit</h4>
<p><a name="gnutls_005fx509_005fcrq_005fdeinit"></a>
<div class="defun">
— Function: void <b>gnutls_x509_crq_deinit</b> (<var>gnutls_x509_crq_t crq</var>)<var><a name="index-gnutls_005fx509_005fcrq_005fdeinit-286"></a></var><br>
<blockquote><p><var>crq</var>: The structure to be initialized
<p>This function will deinitialize a CRL structure.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crq_export</h4>
<p><a name="gnutls_005fx509_005fcrq_005fexport"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crq_export</b> (<var>gnutls_x509_crq_t crq, gnutls_x509_crt_fmt_t format, void * output_data, size_t * output_data_size</var>)<var><a name="index-gnutls_005fx509_005fcrq_005fexport-287"></a></var><br>
<blockquote><p><var>crq</var>: Holds the request
<p><var>format</var>: the format of output params. One of PEM or DER.
<p><var>output_data</var>: will contain a certificate request PEM or DER encoded
<p><var>output_data_size</var>: holds the size of output_data (and will be
replaced by the actual size of parameters)
<p>This function will export the certificate request to a PKCS10
<p>If the buffer provided is not long enough to hold the output, then
GNUTLS_E_SHORT_MEMORY_BUFFER will be returned and
*output_data_size will be updated.
<p>If the structure is PEM encoded, it will have a header of "BEGIN
NEW CERTIFICATE REQUEST".
<p><strong>Return value:</strong> In case of failure a negative value will be
returned, and 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crq_get_attribute_by_oid</h4>
<p><a name="gnutls_005fx509_005fcrq_005fget_005fattribute_005fby_005foid"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crq_get_attribute_by_oid</b> (<var>gnutls_x509_crq_t crq, const char * oid, int indx, void * buf, size_t * sizeof_buf</var>)<var><a name="index-gnutls_005fx509_005fcrq_005fget_005fattribute_005fby_005foid-288"></a></var><br>
<blockquote><p><var>crq</var>: should contain a gnutls_x509_crq_t structure
<p><var>oid</var>: holds an Object Identified in null terminated string
<p><var>indx</var>: In case multiple same OIDs exist in the attribute list, this specifies
which to send. Use zero to get the first one.
<p><var>buf</var>: a pointer to a structure to hold the attribute data (may be null)
<p><var>sizeof_buf</var>: initially holds the size of <code>buf</code>
<p>This function will return the attribute in the certificate request specified
by the given Object ID. The attribute will be DER encoded.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crq_get_challenge_password</h4>
<p><a name="gnutls_005fx509_005fcrq_005fget_005fchallenge_005fpassword"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crq_get_challenge_password</b> (<var>gnutls_x509_crq_t crq, char * pass, size_t * sizeof_pass</var>)<var><a name="index-gnutls_005fx509_005fcrq_005fget_005fchallenge_005fpassword-289"></a></var><br>
<blockquote><p><var>crq</var>: should contain a gnutls_x509_crq_t structure
<p><var>pass</var>: will hold a null terminated password
<p><var>sizeof_pass</var>: Initially holds the size of <code>pass</code>.
<p>This function will return the challenge password in the
request.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crq_get_dn_by_oid</h4>
<p><a name="gnutls_005fx509_005fcrq_005fget_005fdn_005fby_005foid"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crq_get_dn_by_oid</b> (<var>gnutls_x509_crq_t crq, const char * oid, int indx, unsigned int raw_flag, void * buf, size_t * sizeof_buf</var>)<var><a name="index-gnutls_005fx509_005fcrq_005fget_005fdn_005fby_005foid-290"></a></var><br>
<blockquote><p><var>crq</var>: should contain a gnutls_x509_crq_t structure
<p><var>oid</var>: holds an Object Identified in null terminated string
<p><var>indx</var>: In case multiple same OIDs exist in the RDN, this specifies
which to send. Use zero to get the first one.
<p><var>raw_flag</var>: If non zero returns the raw DER data of the DN part.
<p><var>buf</var>: a pointer to a structure to hold the name (may be null)
<p><var>sizeof_buf</var>: initially holds the size of <code>buf</code>
<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>Some helper macros with popular OIDs can be found in gnutls/x509.h
If raw flag is zero, this function will only return known OIDs as
text. Other OIDs will be DER encoded, as described in RFC2253 –
in hex format with a '\#' prefix. You can check about known OIDs
using <code>gnutls_x509_dn_oid_known()</code>.
<p>If <code>buf</code> is null then only the size will be filled.
<p>Returns GNUTLS_E_SHORT_MEMORY_BUFFER if the provided buffer is not
long enough, and in that case the *sizeof_buf will be updated with
the required size. On success 0 is returned.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crq_get_dn_oid</h4>
<p><a name="gnutls_005fx509_005fcrq_005fget_005fdn_005foid"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crq_get_dn_oid</b> (<var>gnutls_x509_crq_t crq, int indx, void * oid, size_t * sizeof_oid</var>)<var><a name="index-gnutls_005fx509_005fcrq_005fget_005fdn_005foid-291"></a></var><br>
<blockquote><p><var>crq</var>: should contain a gnutls_x509_crq_t structure
<p><var>indx</var>: Specifies which DN OID to send. Use zero to get the first one.
<p><var>oid</var>: a pointer to a structure to hold the name (may be null)
<p><var>sizeof_oid</var>: initially holds the size of <code>oid</code>
<p>This function will extract the requested OID of the name of the
Certificate request subject, specified by the given index.
<p>If oid is null then only the size will be filled.
<p>Returns GNUTLS_E_SHORT_MEMORY_BUFFER 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></blockquote></div>
<h4 class="subheading">gnutls_x509_crq_get_dn</h4>
<p><a name="gnutls_005fx509_005fcrq_005fget_005fdn"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crq_get_dn</b> (<var>gnutls_x509_crq_t crq, char * buf, size_t * sizeof_buf</var>)<var><a name="index-gnutls_005fx509_005fcrq_005fget_005fdn-292"></a></var><br>
<blockquote><p><var>crq</var>: should contain a gnutls_x509_crq_t structure
<p><var>buf</var>: a pointer to a structure to hold the name (may be null)
<p><var>sizeof_buf</var>: initially holds the size of <code>buf</code>
<p>This function will copy the name of the Certificate request
subject in the provided buffer. The name will be in the form
"C=xxxx,O=yyyy,CN=zzzz" as described in RFC2253. The output string
will be ASCII or UTF-8 encoded, depending on the certificate data.
<p>If <code>buf</code> is null then only the size will be filled.
<p>Returns GNUTLS_E_SHORT_MEMORY_BUFFER if the provided buffer is not
long enough, and in that case the *sizeof_buf will be updated with
the required size. On success 0 is returned.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crq_get_pk_algorithm</h4>
<p><a name="gnutls_005fx509_005fcrq_005fget_005fpk_005falgorithm"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crq_get_pk_algorithm</b> (<var>gnutls_x509_crq_t crq, unsigned int * bits</var>)<var><a name="index-gnutls_005fx509_005fcrq_005fget_005fpk_005falgorithm-293"></a></var><br>
<blockquote><p><var>crq</var>: should contain a gnutls_x509_crq_t structure
<p><var>bits</var>: if bits is non null it will hold the size of the parameters' in bits
<p>This function will return the public key algorithm of a PKCS \<code>10</code>
certificate request.
<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>Returns a member of the gnutls_pk_algorithm_t enumeration on success,
or a negative value on error.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crq_get_version</h4>
<p><a name="gnutls_005fx509_005fcrq_005fget_005fversion"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crq_get_version</b> (<var>gnutls_x509_crq_t crq</var>)<var><a name="index-gnutls_005fx509_005fcrq_005fget_005fversion-294"></a></var><br>
<blockquote><p><var>crq</var>: should contain a gnutls_x509_crq_t structure
<p>This function will return the version of the specified Certificate request.
<p>Returns a negative value on error.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crq_import</h4>
<p><a name="gnutls_005fx509_005fcrq_005fimport"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crq_import</b> (<var>gnutls_x509_crq_t crq, const gnutls_datum_t * data, gnutls_x509_crt_fmt_t format</var>)<var><a name="index-gnutls_005fx509_005fcrq_005fimport-295"></a></var><br>
<blockquote><p><var>crq</var>: The structure to store the parsed certificate request.
<p><var>data</var>: The DER or PEM encoded certificate.
<p><var>format</var>: One of DER or PEM
<p>This function will convert the given DER or PEM encoded Certificate
to the native gnutls_x509_crq_t format. The output will be stored in <code>cert</code>.
<p>If the Certificate is PEM encoded it should have a header of "NEW CERTIFICATE REQUEST".
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crq_init</h4>
<p><a name="gnutls_005fx509_005fcrq_005finit"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crq_init</b> (<var>gnutls_x509_crq_t * crq</var>)<var><a name="index-gnutls_005fx509_005fcrq_005finit-296"></a></var><br>
<blockquote><p><var>crq</var>: The structure to be initialized
<p>This function will initialize a PKCS10 certificate request structure.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crq_set_attribute_by_oid</h4>
<p><a name="gnutls_005fx509_005fcrq_005fset_005fattribute_005fby_005foid"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crq_set_attribute_by_oid</b> (<var>gnutls_x509_crq_t crq, const char * oid, void * buf, size_t sizeof_buf</var>)<var><a name="index-gnutls_005fx509_005fcrq_005fset_005fattribute_005fby_005foid-297"></a></var><br>
<blockquote><p><var>crq</var>: should contain a gnutls_x509_crq_t structure
<p><var>oid</var>: holds an Object Identified in null terminated string
<p><var>buf</var>: a pointer to a structure that holds the attribute data
<p><var>sizeof_buf</var>: holds the size of <code>buf</code>
<p>This function will set the attribute in the certificate request specified
by the given Object ID. The attribute must be be DER encoded.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crq_set_challenge_password</h4>
<p><a name="gnutls_005fx509_005fcrq_005fset_005fchallenge_005fpassword"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crq_set_challenge_password</b> (<var>gnutls_x509_crq_t crq, const char * pass</var>)<var><a name="index-gnutls_005fx509_005fcrq_005fset_005fchallenge_005fpassword-298"></a></var><br>
<blockquote><p><var>crq</var>: should contain a gnutls_x509_crq_t structure
<p><var>pass</var>: holds a null terminated password
<p>This function will set a challenge password to be used when revoking the request.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crq_set_dn_by_oid</h4>
<p><a name="gnutls_005fx509_005fcrq_005fset_005fdn_005fby_005foid"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crq_set_dn_by_oid</b> (<var>gnutls_x509_crq_t crq, const char * oid, unsigned int raw_flag, const void * data, unsigned int sizeof_data</var>)<var><a name="index-gnutls_005fx509_005fcrq_005fset_005fdn_005fby_005foid-299"></a></var><br>
<blockquote><p><var>crq</var>: should contain a gnutls_x509_crq_t structure
<p><var>oid</var>: holds an Object Identifier in a null terminated string
<p><var>raw_flag</var>: must be 0, or 1 if the data are DER encoded
<p><var>data</var>: a pointer to the input data
<p><var>sizeof_data</var>: holds the size of <code>data</code>
<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>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>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>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crq_set_key</h4>
<p><a name="gnutls_005fx509_005fcrq_005fset_005fkey"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crq_set_key</b> (<var>gnutls_x509_crq_t crq, gnutls_x509_privkey_t key</var>)<var><a name="index-gnutls_005fx509_005fcrq_005fset_005fkey-300"></a></var><br>
<blockquote><p><var>crq</var>: should contain a gnutls_x509_crq_t structure
<p><var>key</var>: holds a private key
<p>This function will set the public parameters from the given private key to the
request. Only RSA keys are currently supported.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crq_set_version</h4>
<p><a name="gnutls_005fx509_005fcrq_005fset_005fversion"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crq_set_version</b> (<var>gnutls_x509_crq_t crq, unsigned int version</var>)<var><a name="index-gnutls_005fx509_005fcrq_005fset_005fversion-301"></a></var><br>
<blockquote><p><var>crq</var>: should contain a gnutls_x509_crq_t structure
<p><var>version</var>: holds the version number. For v1 Requests must be 1.
<p>This function will set the version of the certificate request. For
version 1 requests this must be one.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crq_sign2</h4>
<p><a name="gnutls_005fx509_005fcrq_005fsign2"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crq_sign2</b> (<var>gnutls_x509_crq_t crq, gnutls_x509_privkey_t key, gnutls_digest_algorithm_t dig, unsigned int flags</var>)<var><a name="index-gnutls_005fx509_005fcrq_005fsign2-302"></a></var><br>
<blockquote><p><var>crq</var>: should contain a gnutls_x509_crq_t structure
<p><var>key</var>: holds a private key
<p><var>dig</var>: The message digest to use. GNUTLS_DIG_SHA1 is the safe choice unless you know what you're doing.
<p><var>flags</var>: must be 0
<p>This function will sign the certificate request with a private key.
This must be the same key as the one used in <code>gnutls_x509_crt_set_key()</code> since a
certificate request is self signed.
<p>This must be the last step in a certificate request generation since all
the previously set parameters are now signed.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crq_sign</h4>
<p><a name="gnutls_005fx509_005fcrq_005fsign"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crq_sign</b> (<var>gnutls_x509_crq_t crq, gnutls_x509_privkey_t key</var>)<var><a name="index-gnutls_005fx509_005fcrq_005fsign-303"></a></var><br>
<blockquote><p><var>crq</var>: should contain a gnutls_x509_crq_t structure
<p><var>key</var>: holds a private key
<p>This function is the same a <code>gnutls_x509_crq_sign2()</code> with no flags, and
SHA1 as the hash algorithm.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_check_hostname</h4>
<p><a name="gnutls_005fx509_005fcrt_005fcheck_005fhostname"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_check_hostname</b> (<var>gnutls_x509_crt_t cert, const char * hostname</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fcheck_005fhostname-304"></a></var><br>
<blockquote><p><var>cert</var>: should contain an gnutls_x509_crt_t structure
<p><var>hostname</var>: A null terminated string that contains a DNS name
<p>This function will check if the given certificate's subject matches
the given hostname. This is a basic implementation of the matching
described in RFC2818 (HTTPS), which takes into account wildcards,
and the subject alternative name PKIX extension.
<p>Returns non zero on success, and zero on failure.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_check_issuer</h4>
<p><a name="gnutls_005fx509_005fcrt_005fcheck_005fissuer"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_check_issuer</b> (<var>gnutls_x509_crt_t cert, gnutls_x509_crt_t issuer</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fcheck_005fissuer-305"></a></var><br>
<blockquote><p><var>cert</var>: is the certificate to be checked
<p><var>issuer</var>: is the certificate of a possible issuer
<p>This function will check if the given certificate was issued by the
given issuer. It will return true (1) if the given certificate is issued
by the given issuer, and false (0) if not.
<p>A negative value is returned in case of an error.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_check_revocation</h4>
<p><a name="gnutls_005fx509_005fcrt_005fcheck_005frevocation"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_check_revocation</b> (<var>gnutls_x509_crt_t cert, const gnutls_x509_crl_t * crl_list, int crl_list_length</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fcheck_005frevocation-306"></a></var><br>
<blockquote><p><var>cert</var>: should contain a gnutls_x509_crt_t structure
<p><var>crl_list</var>: should contain a list of gnutls_x509_crl_t structures
<p><var>crl_list_length</var>: the length of the crl_list
<p>This function will return check if the given certificate is revoked.
It is assumed that the CRLs have been verified before.
<p>Returns 0 if the certificate is NOT revoked, and 1 if it is.
A negative value is returned on error.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_cpy_crl_dist_points</h4>
<p><a name="gnutls_005fx509_005fcrt_005fcpy_005fcrl_005fdist_005fpoints"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_cpy_crl_dist_points</b> (<var>gnutls_x509_crt_t dst, gnutls_x509_crt_t src</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fcpy_005fcrl_005fdist_005fpoints-307"></a></var><br>
<blockquote><p><var>dst</var>: should contain a gnutls_x509_crt_t structure
<p><var>src</var>: the certificate where the dist points will be copied from
<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>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_deinit</h4>
<p><a name="gnutls_005fx509_005fcrt_005fdeinit"></a>
<div class="defun">
— Function: void <b>gnutls_x509_crt_deinit</b> (<var>gnutls_x509_crt_t cert</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fdeinit-308"></a></var><br>
<blockquote><p><var>cert</var>: The structure to be initialized
<p>This function will deinitialize a CRL structure.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_export</h4>
<p><a name="gnutls_005fx509_005fcrt_005fexport"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_export</b> (<var>gnutls_x509_crt_t cert, gnutls_x509_crt_fmt_t format, void * output_data, size_t * output_data_size</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fexport-309"></a></var><br>
<blockquote><p><var>cert</var>: Holds the certificate
<p><var>format</var>: the format of output params. One of PEM or DER.
<p><var>output_data</var>: will contain a certificate PEM or DER encoded
<p><var>output_data_size</var>: holds the size of output_data (and will be
replaced by the actual size of parameters)
<p>This function will export the certificate to DER or PEM format.
<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>If the structure is PEM encoded, it will have a header
of "BEGIN CERTIFICATE".
<p><strong>Return value:</strong> In case of failure a negative value will be
returned, and 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_get_activation_time</h4>
<p><a name="gnutls_005fx509_005fcrt_005fget_005factivation_005ftime"></a>
<div class="defun">
— Function: time_t <b>gnutls_x509_crt_get_activation_time</b> (<var>gnutls_x509_crt_t cert</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fget_005factivation_005ftime-310"></a></var><br>
<blockquote><p><var>cert</var>: should contain a gnutls_x509_crt_t structure
<p>This function will return the time this Certificate was or will be activated.
<p>Returns (time_t)-1 on error.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_get_authority_key_id</h4>
<p><a name="gnutls_005fx509_005fcrt_005fget_005fauthority_005fkey_005fid"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_get_authority_key_id</b> (<var>gnutls_x509_crt_t cert, void * ret, size_t * ret_size, unsigned int * critical</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fget_005fauthority_005fkey_005fid-311"></a></var><br>
<blockquote><p><var>cert</var>: should contain a gnutls_x509_crt_t structure
<p><var>critical</var>: will be non zero if the extension is marked as critical (may be null)
<p>This function will return the X.509v3 certificate authority'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.
<p>Returns 0 on success and a negative value in case of an error.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_get_ca_status</h4>
<p><a name="gnutls_005fx509_005fcrt_005fget_005fca_005fstatus"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_get_ca_status</b> (<var>gnutls_x509_crt_t cert, unsigned int * critical</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fget_005fca_005fstatus-312"></a></var><br>
<blockquote><p><var>cert</var>: should contain a gnutls_x509_crt_t structure
<p><var>critical</var>: will be non zero if the extension is marked as critical
<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 zero if the certificate does not have
CA flag set.
<p>A negative value may be returned in case of parsing error.
If the certificate does not contain the basicConstraints extension
GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE will be returned.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_get_crl_dist_points</h4>
<p><a name="gnutls_005fx509_005fcrt_005fget_005fcrl_005fdist_005fpoints"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_get_crl_dist_points</b> (<var>gnutls_x509_crt_t cert, unsigned int seq, void * ret, size_t * ret_size, unsigned int * reason_flags, unsigned int * critical</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fget_005fcrl_005fdist_005fpoints-313"></a></var><br>
<blockquote><p><var>cert</var>: should contain a gnutls_x509_crt_t structure
<p><var>seq</var>: specifies the sequence number of the distribution point (0 for the first one, 1 for the second etc.)
<p><var>ret</var>: is the place where the distribution point will be copied to
<p><var>ret_size</var>: holds the size of ret.
<p><var>reason_flags</var>: Revocation reasons flags.
<p><var>critical</var>: will be non zero if the extension is marked as critical (may be null)
<p>This function will return the CRL distribution points (2.5.29.31), contained in the
given certificate.
<p><code>reason_flags</code> should be an ORed sequence of GNUTLS_CRL_REASON_UNUSED,
GNUTLS_CRL_REASON_KEY_COMPROMISE, GNUTLS_CRL_REASON_CA_COMPROMISE,
GNUTLS_CRL_REASON_AFFILIATION_CHANGED, GNUTLS_CRL_REASON_SUPERSEEDED,
GNUTLS_CRL_REASON_CESSATION_OF_OPERATION, GNUTLS_CRL_REASON_CERTIFICATE_HOLD,
GNUTLS_CRL_REASON_PRIVILEGE_WITHDRAWN, GNUTLS_CRL_REASON_AA_COMPROMISE,
or zero for all possible reasons.
<p>This is specified in X509v3 Certificate Extensions. GNUTLS will return the
distribution point type, or a negative error code on error.
<p>Returns GNUTLS_E_SHORT_MEMORY_BUFFER and updates &ret_size if &ret_size 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 gnutls_x509_subject_alt_name_t.
<p>If the certificate does not have an Alternative name with the specified
sequence number then returns GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE;
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_get_dn_by_oid</h4>
<p><a name="gnutls_005fx509_005fcrt_005fget_005fdn_005fby_005foid"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_get_dn_by_oid</b> (<var>gnutls_x509_crt_t cert, const char * oid, int indx, unsigned int raw_flag, void * buf, size_t * sizeof_buf</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fget_005fdn_005fby_005foid-314"></a></var><br>
<blockquote><p><var>cert</var>: should contain a gnutls_x509_crt_t structure
<p><var>oid</var>: holds an Object Identified in null terminated string
<p><var>indx</var>: In case multiple same OIDs exist in the RDN, this specifies which to send. Use zero to get the first one.
<p><var>raw_flag</var>: If non zero returns the raw DER data of the DN part.
<p><var>buf</var>: a pointer where the DN part will be copied (may be null).
<p><var>sizeof_buf</var>: initially holds the size of <code>buf</code>
<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 RFC2253. Thus a string that is
ASCII or UTF-8 encoded, depending on the certificate data.
<p>Some helper macros with popular OIDs can be found in gnutls/x509.h
If raw flag is zero, this function will only return known OIDs as
text. Other OIDs will be DER encoded, as described in RFC2253 –
in hex format with a '\#' prefix. You can check about known OIDs
using <code>gnutls_x509_dn_oid_known()</code>.
<p>If <code>buf</code> is null then only the size will be filled.
<p>Returns GNUTLS_E_SHORT_MEMORY_BUFFER if the provided buffer is not
long enough, and in that case the *sizeof_buf will be updated with
the required size. On success 0 is returned.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_get_dn_oid</h4>
<p><a name="gnutls_005fx509_005fcrt_005fget_005fdn_005foid"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_get_dn_oid</b> (<var>gnutls_x509_crt_t cert, int indx, void * oid, size_t * sizeof_oid</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fget_005fdn_005foid-315"></a></var><br>
<blockquote><p><var>cert</var>: should contain a gnutls_x509_crt_t structure
<p><var>indx</var>: This specifies which OID to return. Use zero to get the first one.
<p><var>oid</var>: a pointer to a buffer to hold the OID (may be null)
<p><var>sizeof_oid</var>: initially holds the size of <code>oid</code>
<p>This function will extract the OIDs of the name of the Certificate
subject specified by the given index.
<p>If oid is null then only the size will be filled.
<p>Returns GNUTLS_E_SHORT_MEMORY_BUFFER 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></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_get_dn</h4>
<p><a name="gnutls_005fx509_005fcrt_005fget_005fdn"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_get_dn</b> (<var>gnutls_x509_crt_t cert, char * buf, size_t * sizeof_buf</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fget_005fdn-316"></a></var><br>
<blockquote><p><var>cert</var>: should contain a gnutls_x509_crt_t structure
<p><var>buf</var>: a pointer to a structure to hold the name (may be null)
<p><var>sizeof_buf</var>: initially holds the size of <code>buf</code>
<p>This function will copy the name of the Certificate in the
provided buffer. The name will be in the form
"C=xxxx,O=yyyy,CN=zzzz" as described in RFC2253. The output string
will be ASCII or UTF-8 encoded, depending on the certificate data.
<p>If <code>buf</code> is null then only the size will be filled.
<p>Returns GNUTLS_E_SHORT_MEMORY_BUFFER if the provided buffer is not
long enough, and in that case the *sizeof_buf will be updated with
the required size. On success 0 is returned.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_get_expiration_time</h4>
<p><a name="gnutls_005fx509_005fcrt_005fget_005fexpiration_005ftime"></a>
<div class="defun">
— Function: time_t <b>gnutls_x509_crt_get_expiration_time</b> (<var>gnutls_x509_crt_t cert</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fget_005fexpiration_005ftime-317"></a></var><br>
<blockquote><p><var>cert</var>: should contain a gnutls_x509_crt_t structure
<p>This function will return the time this Certificate was or will be expired.
<p>Returns (time_t)-1 on error.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_get_extension_by_oid</h4>
<p><a name="gnutls_005fx509_005fcrt_005fget_005fextension_005fby_005foid"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_get_extension_by_oid</b> (<var>gnutls_x509_crt_t cert, const char * oid, int indx, void * buf, size_t * sizeof_buf, unsigned int * critical</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fget_005fextension_005fby_005foid-318"></a></var><br>
<blockquote><p><var>cert</var>: should contain a gnutls_x509_crt_t structure
<p><var>oid</var>: holds an Object Identified in null terminated string
<p><var>indx</var>: In case multiple same OIDs exist in the extensions, this specifies which to send. Use zero to get the first one.
<p><var>buf</var>: a pointer to a structure to hold the name (may be null)
<p><var>sizeof_buf</var>: initially holds the size of <code>buf</code>
<p><var>critical</var>: will be non zero if the extension is marked as critical
<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>A negative value may be returned in case of parsing error.
If the certificate does not contain the specified extension
GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE will be returned.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_get_extension_oid</h4>
<p><a name="gnutls_005fx509_005fcrt_005fget_005fextension_005foid"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_get_extension_oid</b> (<var>gnutls_x509_crt_t cert, int indx, void * oid, size_t * sizeof_oid</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fget_005fextension_005foid-319"></a></var><br>
<blockquote><p><var>cert</var>: should contain a gnutls_x509_crt_t structure
<p><var>indx</var>: Specifies which extension OID to send. Use zero to get the first one.
<p><var>oid</var>: a pointer to a structure to hold the OID (may be null)
<p><var>sizeof_oid</var>: initially holds the size of <code>oid</code>
<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>A negative value may be returned in case of parsing error.
If your have reached the last extension available
GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE will be returned.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_get_fingerprint</h4>
<p><a name="gnutls_005fx509_005fcrt_005fget_005ffingerprint"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_get_fingerprint</b> (<var>gnutls_x509_crt_t cert, gnutls_digest_algorithm_t algo, void * buf, size_t * sizeof_buf</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fget_005ffingerprint-320"></a></var><br>
<blockquote><p><var>cert</var>: should contain a gnutls_x509_crt_t structure
<p><var>algo</var>: is a digest algorithm
<p><var>buf</var>: a pointer to a structure to hold the fingerprint (may be null)
<p><var>sizeof_buf</var>: initially holds the size of <code>buf</code>
<p>This function will calculate and copy the certificate's fingerprint
in the provided buffer.
<p>If the buffer is null then only the size will be filled.
<p>Returns GNUTLS_E_SHORT_MEMORY_BUFFER if the provided buffer is not
long enough, and in that case the *sizeof_buf will be updated with
the required size. On success 0 is returned.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_get_issuer_dn_by_oid</h4>
<p><a name="gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn_005fby_005foid"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_get_issuer_dn_by_oid</b> (<var>gnutls_x509_crt_t cert, const char * oid, int indx, unsigned int raw_flag, void * buf, size_t * sizeof_buf</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn_005fby_005foid-321"></a></var><br>
<blockquote><p><var>cert</var>: should contain a gnutls_x509_crt_t structure
<p><var>oid</var>: holds an Object Identified in null terminated string
<p><var>indx</var>: In case multiple same OIDs exist in the RDN, this specifies which to send. Use zero to get the first one.
<p><var>raw_flag</var>: If non zero returns the raw DER data of the DN part.
<p><var>buf</var>: a pointer to a structure to hold the name (may be null)
<p><var>sizeof_buf</var>: initially holds the size of <code>buf</code>
<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 RFC2253. Thus a string that is
ASCII or UTF-8 encoded, depending on the certificate data.
<p>Some helper macros with popular OIDs can be found in gnutls/x509.h
If raw flag is zero, this function will only return known OIDs as
text. Other OIDs will be DER encoded, as described in RFC2253 –
in hex format with a '\#' prefix. You can check about known OIDs
using <code>gnutls_x509_dn_oid_known()</code>.
<p>If <code>buf</code> is null then only the size will be filled.
<p>Returns GNUTLS_E_SHORT_MEMORY_BUFFER if the provided buffer is not
long enough, and in that case the *sizeof_buf will be updated with
the required size. On success 0 is returned.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_get_issuer_dn_oid</h4>
<p><a name="gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn_005foid"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_get_issuer_dn_oid</b> (<var>gnutls_x509_crt_t cert, int indx, void * oid, size_t * sizeof_oid</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn_005foid-322"></a></var><br>
<blockquote><p><var>cert</var>: should contain a gnutls_x509_crt_t structure
<p><var>indx</var>: This specifies which OID to return. Use zero to get the first one.
<p><var>oid</var>: a pointer to a buffer to hold the OID (may be null)
<p><var>sizeof_oid</var>: initially holds the size of <code>oid</code>
<p>This function will extract the OIDs of the name of the Certificate
issuer specified by the given index.
<p>If <code>oid</code> is null then only the size will be filled.
<p>Returns GNUTLS_E_SHORT_MEMORY_BUFFER 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></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_get_issuer_dn</h4>
<p><a name="gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_get_issuer_dn</b> (<var>gnutls_x509_crt_t cert, char * buf, size_t * sizeof_buf</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn-323"></a></var><br>
<blockquote><p><var>cert</var>: should contain a gnutls_x509_crt_t structure
<p><var>buf</var>: a pointer to a structure to hold the name (may be null)
<p><var>sizeof_buf</var>: initially holds the size of <code>buf</code>
<p>This function will copy the name of the Certificate issuer in the
provided buffer. The name will be in the form
"C=xxxx,O=yyyy,CN=zzzz" as described in RFC2253. The output string
will be ASCII or UTF-8 encoded, depending on the certificate data.
<p>If <code>buf</code> is null then only the size will be filled.
<p>Returns GNUTLS_E_SHORT_MEMORY_BUFFER if the provided buffer is not
long enough, and in that case the *sizeof_buf will be updated with
the required size. On success 0 is returned.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_get_key_id</h4>
<p><a name="gnutls_005fx509_005fcrt_005fget_005fkey_005fid"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_get_key_id</b> (<var>gnutls_x509_crt_t crt, unsigned int flags, unsigned char * output_data, size_t * output_data_size</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fget_005fkey_005fid-324"></a></var><br>
<blockquote><p><var>crt</var>: Holds the certificate
<p><var>flags</var>: should be 0 for now
<p><var>output_data</var>: will contain the key ID
<p><var>output_data_size</var>: holds the size of output_data (and will be
replaced by the actual size of parameters)
<p>This function will return a unique ID the depends on the public key
parameters. This ID can be used in checking whether a certificate
corresponds to the given private key.
<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><strong>Return value:</strong> In case of failure a negative value will be
returned, and 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_get_key_purpose_oid</h4>
<p><a name="gnutls_005fx509_005fcrt_005fget_005fkey_005fpurpose_005foid"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_get_key_purpose_oid</b> (<var>gnutls_x509_crt_t cert, int indx, void * oid, size_t * sizeof_oid, unsigned int * critical</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fget_005fkey_005fpurpose_005foid-325"></a></var><br>
<blockquote><p><var>cert</var>: should contain a gnutls_x509_crt_t structure
<p><var>indx</var>: This specifies which OID to return. Use zero to get the first one.
<p><var>oid</var>: a pointer to a buffer to hold the OID (may be null)
<p><var>sizeof_oid</var>: initially holds the size of <code>oid</code>
<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>If <code>oid</code> is null then only the size will be filled.
<p>Returns GNUTLS_E_SHORT_MEMORY_BUFFER 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></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_get_key_usage</h4>
<p><a name="gnutls_005fx509_005fcrt_005fget_005fkey_005fusage"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_get_key_usage</b> (<var>gnutls_x509_crt_t cert, unsigned int * key_usage, unsigned int * critical</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fget_005fkey_005fusage-326"></a></var><br>
<blockquote><p><var>cert</var>: should contain a gnutls_x509_crt_t structure
<p><var>key_usage</var>: where the key usage bits will be stored
<p><var>critical</var>: will be non zero if the extension is marked as critical
<p>This function will return certificate's key usage, by reading the
keyUsage X.509 extension (2.5.29.15). The key usage value will ORed values of the:
GNUTLS_KEY_DIGITAL_SIGNATURE, GNUTLS_KEY_NON_REPUDIATION,
GNUTLS_KEY_KEY_ENCIPHERMENT, GNUTLS_KEY_DATA_ENCIPHERMENT,
GNUTLS_KEY_KEY_AGREEMENT, GNUTLS_KEY_KEY_CERT_SIGN,
GNUTLS_KEY_CRL_SIGN, GNUTLS_KEY_ENCIPHER_ONLY,
GNUTLS_KEY_DECIPHER_ONLY.
<p>A negative value may be returned in case of parsing error.
If the certificate does not contain the keyUsage extension
GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE will be returned.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_get_pk_algorithm</h4>
<p><a name="gnutls_005fx509_005fcrt_005fget_005fpk_005falgorithm"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_get_pk_algorithm</b> (<var>gnutls_x509_crt_t cert, unsigned int * bits</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fget_005fpk_005falgorithm-327"></a></var><br>
<blockquote><p><var>cert</var>: should contain a gnutls_x509_crt_t structure
<p><var>bits</var>: if bits is non null it will hold the size of the parameters' in bits
<p>This function will return the public key algorithm of an X.509
certificate.
<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>Returns a member of the gnutls_pk_algorithm_t enumeration on success,
or a negative value on error.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_get_pk_dsa_raw</h4>
<p><a name="gnutls_005fx509_005fcrt_005fget_005fpk_005fdsa_005fraw"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_get_pk_dsa_raw</b> (<var>gnutls_x509_crt_t crt, gnutls_datum_t * p, gnutls_datum_t * q, gnutls_datum_t * g, gnutls_datum_t * y</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fget_005fpk_005fdsa_005fraw-328"></a></var><br>
<blockquote><p><var>crt</var>: Holds the certificate
<p><var>p</var>: will hold the p
<p><var>q</var>: will hold the q
<p><var>g</var>: will hold the g
<p><var>y</var>: will hold the y
<p>This function will export the DSA private key's parameters found in the given
certificate. The new parameters will be allocated using
<code>gnutls_malloc()</code> and will be stored in the appropriate datum.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_get_pk_rsa_raw</h4>
<p><a name="gnutls_005fx509_005fcrt_005fget_005fpk_005frsa_005fraw"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_get_pk_rsa_raw</b> (<var>gnutls_x509_crt_t crt, gnutls_datum_t * m, gnutls_datum_t * e</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fget_005fpk_005frsa_005fraw-329"></a></var><br>
<blockquote><p><var>crt</var>: Holds the certificate
<p><var>m</var>: will hold the modulus
<p><var>e</var>: will hold the public exponent
<p>This function will export the RSA private key's parameters found in the given
structure. The new parameters will be allocated using
<code>gnutls_malloc()</code> and will be stored in the appropriate datum.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_get_serial</h4>
<p><a name="gnutls_005fx509_005fcrt_005fget_005fserial"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_get_serial</b> (<var>gnutls_x509_crt_t cert, void * result, size_t * result_size</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fget_005fserial-330"></a></var><br>
<blockquote><p><var>cert</var>: should contain a gnutls_x509_crt_t structure
<p><var>result</var>: The place where the serial number will be copied
<p><var>result_size</var>: Holds the size of the result field.
<p>This function will return the X.509 certificate'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
opaque.
<p>Returns 0 on success and a negative value in case of an error.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_get_signature_algorithm</h4>
<p><a name="gnutls_005fx509_005fcrt_005fget_005fsignature_005falgorithm"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_get_signature_algorithm</b> (<var>gnutls_x509_crt_t cert</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fget_005fsignature_005falgorithm-331"></a></var><br>
<blockquote><p><var>cert</var>: should contain a gnutls_x509_crt_t structure
<p>This function will return a value of the gnutls_sign_algorithm_t enumeration that
is the signature algorithm.
<p>Returns a negative value on error.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_get_subject_alt_name</h4>
<p><a name="gnutls_005fx509_005fcrt_005fget_005fsubject_005falt_005fname"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_get_subject_alt_name</b> (<var>gnutls_x509_crt_t cert, unsigned int seq, void * ret, size_t * ret_size, unsigned int * critical</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fget_005fsubject_005falt_005fname-332"></a></var><br>
<blockquote><p><var>cert</var>: should contain a gnutls_x509_crt_t structure
<p><var>seq</var>: specifies the sequence number of the alt name (0 for the first one, 1 for the second etc.)
<p><var>ret</var>: is the place where the alternative name will be copied to
<p><var>ret_size</var>: holds the size of ret.
<p><var>critical</var>: will be non zero if the extension is marked as critical (may be null)
<p>This function will return the alternative names, contained in the
given certificate.
<p>This is specified in X509v3 Certificate Extensions.
GNUTLS will return the Alternative name (2.5.29.17), or a negative
error code.
<p>Returns GNUTLS_E_SHORT_MEMORY_BUFFER if &ret_size is not enough to hold the alternative
name. In that case &ret_size will be updated. If everything was ok the type of alternative
name is returned. The type is one of the enumerated gnutls_x509_subject_alt_name_t.
<p>If the certificate does not have an Alternative name with the specified
sequence number then returns GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE;
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_get_subject_key_id</h4>
<p><a name="gnutls_005fx509_005fcrt_005fget_005fsubject_005fkey_005fid"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_get_subject_key_id</b> (<var>gnutls_x509_crt_t cert, void * ret, size_t * ret_size, unsigned int * critical</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fget_005fsubject_005fkey_005fid-333"></a></var><br>
<blockquote><p><var>cert</var>: should contain a gnutls_x509_crt_t structure
<p><var>critical</var>: will be non zero if the extension is marked as critical (may be null)
<p>This function will return the X.509v3 certificate's subject key identifier.
This is obtained by the X.509 Subject Key identifier extension
field (2.5.29.14).
<p>Returns 0 on success and a negative value in case of an error.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_get_version</h4>
<p><a name="gnutls_005fx509_005fcrt_005fget_005fversion"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_get_version</b> (<var>gnutls_x509_crt_t cert</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fget_005fversion-334"></a></var><br>
<blockquote><p><var>cert</var>: should contain a gnutls_x509_crt_t structure
<p>This function will return the version of the specified Certificate.
<p>Returns a negative value on error.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_import</h4>
<p><a name="gnutls_005fx509_005fcrt_005fimport"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_import</b> (<var>gnutls_x509_crt_t cert, const gnutls_datum_t * data, gnutls_x509_crt_fmt_t format</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fimport-335"></a></var><br>
<blockquote><p><var>cert</var>: The structure to store the parsed certificate.
<p><var>data</var>: The DER or PEM encoded certificate.
<p><var>format</var>: One of DER or PEM
<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>cert</code>.
<p>If the Certificate is PEM encoded it should have a header of "X509 CERTIFICATE", or
"CERTIFICATE".
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_init</h4>
<p><a name="gnutls_005fx509_005fcrt_005finit"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_init</b> (<var>gnutls_x509_crt_t * cert</var>)<var><a name="index-gnutls_005fx509_005fcrt_005finit-336"></a></var><br>
<blockquote><p><var>cert</var>: The structure to be initialized
<p>This function will initialize an X.509 certificate structure.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_list_import</h4>
<p><a name="gnutls_005fx509_005fcrt_005flist_005fimport"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_list_import</b> (<var>gnutls_x509_crt_t * certs, unsigned int * cert_max, const gnutls_datum_t * data, gnutls_x509_crt_fmt_t format, unsigned int flags</var>)<var><a name="index-gnutls_005fx509_005fcrt_005flist_005fimport-337"></a></var><br>
<blockquote><p><var>certs</var>: The structures to store the parsed certificate. Must not be initialized.
<p><var>cert_max</var>: Initially must hold the maximum number of certs. It will be updated with the number of certs available.
<p><var>data</var>: The PEM encoded certificate.
<p><var>format</var>: One of DER or PEM.
<p><var>flags</var>: must be zero or an OR'd sequence of gnutls_certificate_import_flags.
<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>certs</code>.
They will be automatically initialized.
<p>If the Certificate is PEM encoded it should have a header of "X509 CERTIFICATE", or
"CERTIFICATE".
<p>Returns the number of certificates read or a negative error value.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_list_verify</h4>
<p><a name="gnutls_005fx509_005fcrt_005flist_005fverify"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_list_verify</b> (<var>const gnutls_x509_crt_t * cert_list, int cert_list_length, const gnutls_x509_crt_t * CA_list, int CA_list_length, const gnutls_x509_crl_t * CRL_list, int CRL_list_length, unsigned int flags, unsigned int * verify</var>)<var><a name="index-gnutls_005fx509_005fcrt_005flist_005fverify-338"></a></var><br>
<blockquote><p><var>cert_list</var>: is the certificate list to be verified
<p><var>cert_list_length</var>: holds the number of certificate in cert_list
<p><var>CA_list</var>: is the CA list which will be used in verification
<p><var>CA_list_length</var>: holds the number of CA certificate in CA_list
<p><var>CRL_list</var>: holds a list of CRLs.
<p><var>CRL_list_length</var>: the length of CRL list.
<p><var>flags</var>: Flags that may be used to change the verification algorithm. Use OR of the gnutls_certificate_verify_flags enumerations.
<p><var>verify</var>: will hold the certificate verification output.
<p>This function will try to verify the given certificate list and return its status.
Note that expiration and activation dates are not checked
by this function, you should check them using the appropriate functions.
<p>If no flags are specified (0), this function will use the
basicConstraints (2.5.29.19) PKIX extension. This means that only a certificate
authority is allowed to sign a certificate.
<p>You must also check the peer's name in order to check if the verified
certificate belongs to the actual peer.
<p>The certificate verification output will be put in <code>verify</code> and will be
one or more of the gnutls_certificate_status_t enumerated elements bitwise or'd.
For a more detailed verification status use <code>gnutls_x509_crt_verify()</code> per list
element.
<p><strong>GNUTLS_CERT_INVALID:</strong> the certificate chain is not valid.
<p><strong>GNUTLS_CERT_REVOKED:</strong> a certificate in the chain has been revoked.
<p>Returns 0 on success and a negative value in case of an error.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_set_activation_time</h4>
<p><a name="gnutls_005fx509_005fcrt_005fset_005factivation_005ftime"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_set_activation_time</b> (<var>gnutls_x509_crt_t cert, time_t act_time</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fset_005factivation_005ftime-339"></a></var><br>
<blockquote><p><var>cert</var>: should contain a gnutls_x509_crt_t structure
<p><var>act_time</var>: The actual time
<p>This function will set the time this Certificate was or will be activated.
<p>Returns 0 on success, or a negative value in case of an error.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_set_authority_key_id</h4>
<p><a name="gnutls_005fx509_005fcrt_005fset_005fauthority_005fkey_005fid"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_set_authority_key_id</b> (<var>gnutls_x509_crt_t cert, const void * id, size_t id_size</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fset_005fauthority_005fkey_005fid-340"></a></var><br>
<blockquote><p><var>cert</var>: should contain a gnutls_x509_crt_t structure
<p><var>id</var>: The key ID
<p><var>id_size</var>: Holds the size of the serial field.
<p>This function will set the X.509 certificate's authority key ID extension.
Only the keyIdentifier field can be set with this function.
<p>Returns 0 on success, or a negative value in case of an error.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_set_ca_status</h4>
<p><a name="gnutls_005fx509_005fcrt_005fset_005fca_005fstatus"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_set_ca_status</b> (<var>gnutls_x509_crt_t crt, unsigned int ca</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fset_005fca_005fstatus-341"></a></var><br>
<blockquote><p><var>crt</var>: should contain a gnutls_x509_crt_t structure
<p><var>ca</var>: true(1) or false(0). Depending on the Certificate authority status.
<p>This function will set the basicConstraints certificate extension.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_set_crl_dist_points</h4>
<p><a name="gnutls_005fx509_005fcrt_005fset_005fcrl_005fdist_005fpoints"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_set_crl_dist_points</b> (<var>gnutls_x509_crt_t crt, gnutls_x509_subject_alt_name_t type, const void * data_string, unsigned int reason_flags</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fset_005fcrl_005fdist_005fpoints-342"></a></var><br>
<blockquote><p><var>crt</var>: should contain a gnutls_x509_crt_t structure
<p><var>type</var>: is one of the gnutls_x509_subject_alt_name_t enumerations
<p><var>data_string</var>: The data to be set
<p><var>reason_flags</var>: revocation reasons
<p>This function will set the CRL distribution points certificate extension.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_set_crq</h4>
<p><a name="gnutls_005fx509_005fcrt_005fset_005fcrq"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_set_crq</b> (<var>gnutls_x509_crt_t crt, gnutls_x509_crq_t crq</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fset_005fcrq-343"></a></var><br>
<blockquote><p><var>crt</var>: should contain a gnutls_x509_crt_t structure
<p><var>crq</var>: holds a certificate request
<p>This function will set the name and public parameters from the given certificate request to the
certificate. Only RSA keys are currently supported.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_set_dn_by_oid</h4>
<p><a name="gnutls_005fx509_005fcrt_005fset_005fdn_005fby_005foid"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_set_dn_by_oid</b> (<var>gnutls_x509_crt_t crt, const char * oid, unsigned int raw_flag, const void * name, unsigned int sizeof_name</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fset_005fdn_005fby_005foid-344"></a></var><br>
<blockquote><p><var>crt</var>: should contain a gnutls_x509_crt_t structure
<p><var>oid</var>: holds an Object Identifier in a null terminated string
<p><var>raw_flag</var>: must be 0, or 1 if the data are DER encoded
<p><var>name</var>: a pointer to the name
<p><var>sizeof_name</var>: holds the size of <code>name</code>
<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>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>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>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_set_expiration_time</h4>
<p><a name="gnutls_005fx509_005fcrt_005fset_005fexpiration_005ftime"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_set_expiration_time</b> (<var>gnutls_x509_crt_t cert, time_t exp_time</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fset_005fexpiration_005ftime-345"></a></var><br>
<blockquote><p><var>cert</var>: should contain a gnutls_x509_crt_t structure
<p><var>exp_time</var>: The actual time
<p>This function will set the time this Certificate will expire.
<p>Returns 0 on success, or a negative value in case of an error.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_set_extension_by_oid</h4>
<p><a name="gnutls_005fx509_005fcrt_005fset_005fextension_005fby_005foid"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_set_extension_by_oid</b> (<var>gnutls_x509_crt_t crt, const char * oid, const void * buf, size_t sizeof_buf, unsigned int critical</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fset_005fextension_005fby_005foid-346"></a></var><br>
<blockquote><p><var>crt</var>: should contain a gnutls_x509_crt_t structure
<p><var>oid</var>: holds an Object Identified in null terminated string
<p><var>buf</var>: a pointer to a DER encoded data
<p><var>sizeof_buf</var>: holds the size of <code>buf</code>
<p><var>critical</var>: should be non zero if the extension is to be marked as critical
<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>Returns 0 on success and a negative value in case of an error.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_set_issuer_dn_by_oid</h4>
<p><a name="gnutls_005fx509_005fcrt_005fset_005fissuer_005fdn_005fby_005foid"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_set_issuer_dn_by_oid</b> (<var>gnutls_x509_crt_t crt, const char * oid, unsigned int raw_flag, const void * name, unsigned int sizeof_name</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fset_005fissuer_005fdn_005fby_005foid-347"></a></var><br>
<blockquote><p><var>crt</var>: should contain a gnutls_x509_crt_t structure
<p><var>oid</var>: holds an Object Identifier in a null terminated string
<p><var>raw_flag</var>: must be 0, or 1 if the data are DER encoded
<p><var>name</var>: a pointer to the name
<p><var>sizeof_name</var>: holds the size of <code>name</code>
<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>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>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>Normally you do not need to call this function, since the signing
operation will copy the signer's name as the issuer of the certificate.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_set_key_purpose_oid</h4>
<p><a name="gnutls_005fx509_005fcrt_005fset_005fkey_005fpurpose_005foid"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_set_key_purpose_oid</b> (<var>gnutls_x509_crt_t cert, const void * oid, unsigned int critical</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fset_005fkey_005fpurpose_005foid-348"></a></var><br>
<blockquote><p><var>cert</var>: should contain a gnutls_x509_crt_t structure
<p><var>oid</var>: a pointer to a null terminated string that holds the OID
<p><var>critical</var>: Whether this extension will be critical or not
<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>Subsequent calls to this function will append OIDs to the OID list.
<p>On success 0 is returned.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_set_key_usage</h4>
<p><a name="gnutls_005fx509_005fcrt_005fset_005fkey_005fusage"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_set_key_usage</b> (<var>gnutls_x509_crt_t crt, unsigned int usage</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fset_005fkey_005fusage-349"></a></var><br>
<blockquote><p><var>crt</var>: should contain a gnutls_x509_crt_t structure
<p><var>usage</var>: an ORed sequence of the GNUTLS_KEY_* elements.
<p>This function will set the keyUsage certificate extension.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_set_key</h4>
<p><a name="gnutls_005fx509_005fcrt_005fset_005fkey"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_set_key</b> (<var>gnutls_x509_crt_t crt, gnutls_x509_privkey_t key</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fset_005fkey-350"></a></var><br>
<blockquote><p><var>crt</var>: should contain a gnutls_x509_crt_t structure
<p><var>key</var>: holds a private key
<p>This function will set the public parameters from the given private key to the
certificate. Only RSA keys are currently supported.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_set_serial</h4>
<p><a name="gnutls_005fx509_005fcrt_005fset_005fserial"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_set_serial</b> (<var>gnutls_x509_crt_t cert, const void * serial, size_t serial_size</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fset_005fserial-351"></a></var><br>
<blockquote><p><var>cert</var>: should contain a gnutls_x509_crt_t structure
<p><var>serial</var>: The serial number
<p><var>serial_size</var>: Holds the size of the serial field.
<p>This function will set the X.509 certificate's serial number.
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
opaque.
<p>Returns 0 on success, or a negative value in case of an error.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_set_subject_alternative_name</h4>
<p><a name="gnutls_005fx509_005fcrt_005fset_005fsubject_005falternative_005fname"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_set_subject_alternative_name</b> (<var>gnutls_x509_crt_t crt, gnutls_x509_subject_alt_name_t type, const char * data_string</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fset_005fsubject_005falternative_005fname-352"></a></var><br>
<blockquote><p><var>crt</var>: should contain a gnutls_x509_crt_t structure
<p><var>type</var>: is one of the gnutls_x509_subject_alt_name_t enumerations
<p><var>data_string</var>: The data to be set
<p>This function will set the subject alternative name certificate extension.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_set_subject_key_id</h4>
<p><a name="gnutls_005fx509_005fcrt_005fset_005fsubject_005fkey_005fid"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_set_subject_key_id</b> (<var>gnutls_x509_crt_t cert, const void * id, size_t id_size</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fset_005fsubject_005fkey_005fid-353"></a></var><br>
<blockquote><p><var>cert</var>: should contain a gnutls_x509_crt_t structure
<p><var>id</var>: The key ID
<p><var>id_size</var>: Holds the size of the serial field.
<p>This function will set the X.509 certificate's subject key ID extension.
<p>Returns 0 on success, or a negative value in case of an error.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_set_version</h4>
<p><a name="gnutls_005fx509_005fcrt_005fset_005fversion"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_set_version</b> (<var>gnutls_x509_crt_t crt, unsigned int version</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fset_005fversion-354"></a></var><br>
<blockquote><p><var>crt</var>: should contain a gnutls_x509_crt_t structure
<p><var>version</var>: holds the version number. For X.509v1 certificates must be 1.
<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>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_sign2</h4>
<p><a name="gnutls_005fx509_005fcrt_005fsign2"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_sign2</b> (<var>gnutls_x509_crt_t crt, gnutls_x509_crt_t issuer, gnutls_x509_privkey_t issuer_key, gnutls_digest_algorithm_t dig, unsigned int flags</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fsign2-355"></a></var><br>
<blockquote><p><var>crt</var>: should contain a gnutls_x509_crt_t structure
<p><var>issuer</var>: is the certificate of the certificate issuer
<p><var>issuer_key</var>: holds the issuer's private key
<p><var>dig</var>: The message digest to use. GNUTLS_DIG_SHA1 is the safe choice unless you know what you're doing.
<p><var>flags</var>: must be 0
<p>This function will sign the certificate with the issuer's private key, and
will copy the issuer's information into the certificate.
<p>This must be the last step in a certificate generation since all
the previously set parameters are now signed.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_sign</h4>
<p><a name="gnutls_005fx509_005fcrt_005fsign"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_sign</b> (<var>gnutls_x509_crt_t crt, gnutls_x509_crt_t issuer, gnutls_x509_privkey_t issuer_key</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fsign-356"></a></var><br>
<blockquote><p><var>crt</var>: should contain a gnutls_x509_crt_t structure
<p><var>issuer</var>: is the certificate of the certificate issuer
<p><var>issuer_key</var>: holds the issuer's private key
<p>This function is the same a <code>gnutls_x509_crt_sign2()</code> with no flags, and
SHA1 as the hash algorithm.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_to_xml</h4>
<p><a name="gnutls_005fx509_005fcrt_005fto_005fxml"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_to_xml</b> (<var>gnutls_x509_crt_t cert, gnutls_datum_t * res, int detail</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fto_005fxml-357"></a></var><br>
<blockquote><p><var>cert</var>: should contain a gnutls_x509_crt_t structure
<p><var>res</var>: The datum that will hold the result
<p><var>detail</var>: The detail level (must be GNUTLS_XML_SHOW_ALL or GNUTLS_XML_NORMAL)
<p>This function will return the XML structures of the given X.509
certificate. The XML structures are allocated internally (with
malloc) and stored into res.
<p><strong>NOTE:</strong> This function is currently not implemented. See the NEWS
entry for version 1.3.5.
<p>Returns a negative error code in case of an error.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_verify_data</h4>
<p><a name="gnutls_005fx509_005fcrt_005fverify_005fdata"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_verify_data</b> (<var>gnutls_x509_crt_t crt, unsigned int flags, const gnutls_datum_t * data, const gnutls_datum_t * signature</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fverify_005fdata-358"></a></var><br>
<blockquote><p><var>crt</var>: Holds the certificate
<p><var>flags</var>: should be 0 for now
<p><var>data</var>: holds the data to be signed
<p><var>signature</var>: contains the signature
<p>This function will verify the given signed data, using the parameters from the
certificate.
<p>In case of a verification failure 0 is returned, and
1 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_crt_verify</h4>
<p><a name="gnutls_005fx509_005fcrt_005fverify"></a>
<div class="defun">
— Function: int <b>gnutls_x509_crt_verify</b> (<var>gnutls_x509_crt_t cert, const gnutls_x509_crt_t * CA_list, int CA_list_length, unsigned int flags, unsigned int * verify</var>)<var><a name="index-gnutls_005fx509_005fcrt_005fverify-359"></a></var><br>
<blockquote><p><var>cert</var>: is the certificate to be verified
<p><var>CA_list</var>: is one certificate that is considered to be trusted one
<p><var>CA_list_length</var>: holds the number of CA certificate in CA_list
<p><var>flags</var>: Flags that may be used to change the verification algorithm. Use OR of the gnutls_certificate_verify_flags enumerations.
<p><var>verify</var>: will hold the certificate verification output.
<p>This function will try to verify the given certificate and return its status.
The verification output in this functions cannot be GNUTLS_CERT_NOT_VALID.
<p>Returns 0 on success and a negative value in case of an error.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_dn_oid_known</h4>
<p><a name="gnutls_005fx509_005fdn_005foid_005fknown"></a>
<div class="defun">
— Function: int <b>gnutls_x509_dn_oid_known</b> (<var>const char * oid</var>)<var><a name="index-gnutls_005fx509_005fdn_005foid_005fknown-360"></a></var><br>
<blockquote><p><var>oid</var>: holds an Object Identifier in a null terminated string
<p>This function will inform about known DN OIDs. This is useful since functions
like <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>Returns 1 on known OIDs and 0 otherwise.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_privkey_cpy</h4>
<p><a name="gnutls_005fx509_005fprivkey_005fcpy"></a>
<div class="defun">
— Function: int <b>gnutls_x509_privkey_cpy</b> (<var>gnutls_x509_privkey_t dst, gnutls_x509_privkey_t src</var>)<var><a name="index-gnutls_005fx509_005fprivkey_005fcpy-361"></a></var><br>
<blockquote><p><var>dst</var>: The destination key, which should be initialized.
<p><var>src</var>: The source key
<p>This function will copy a private key from source to destination key.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_privkey_deinit</h4>
<p><a name="gnutls_005fx509_005fprivkey_005fdeinit"></a>
<div class="defun">
— Function: void <b>gnutls_x509_privkey_deinit</b> (<var>gnutls_x509_privkey_t key</var>)<var><a name="index-gnutls_005fx509_005fprivkey_005fdeinit-362"></a></var><br>
<blockquote><p><var>key</var>: The structure to be initialized
<p>This function will deinitialize a private key structure.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_privkey_export_dsa_raw</h4>
<p><a name="gnutls_005fx509_005fprivkey_005fexport_005fdsa_005fraw"></a>
<div class="defun">
— Function: int <b>gnutls_x509_privkey_export_dsa_raw</b> (<var>gnutls_x509_privkey_t key, gnutls_datum_t * p, gnutls_datum_t * q, gnutls_datum_t * g, gnutls_datum_t * y, gnutls_datum_t * x</var>)<var><a name="index-gnutls_005fx509_005fprivkey_005fexport_005fdsa_005fraw-363"></a></var><br>
<blockquote><p><var>p</var>: will hold the p
<p><var>q</var>: will hold the q
<p><var>g</var>: will hold the g
<p><var>y</var>: will hold the y
<p><var>x</var>: will hold the x
<p>This function will export the DSA private key's parameters found in the given
structure. The new parameters will be allocated using
<code>gnutls_malloc()</code> and will be stored in the appropriate datum.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_privkey_export_pkcs8</h4>
<p><a name="gnutls_005fx509_005fprivkey_005fexport_005fpkcs8"></a>
<div class="defun">
— Function: int <b>gnutls_x509_privkey_export_pkcs8</b> (<var>gnutls_x509_privkey_t key, gnutls_x509_crt_fmt_t format, const char * password, unsigned int flags, void * output_data, size_t * output_data_size</var>)<var><a name="index-gnutls_005fx509_005fprivkey_005fexport_005fpkcs8-364"></a></var><br>
<blockquote><p><var>key</var>: Holds the key
<p><var>format</var>: the format of output params. One of PEM or DER.
<p><var>password</var>: the password that will be used to encrypt the key.
<p><var>flags</var>: an ORed sequence of gnutls_pkcs_encrypt_flags_t
<p><var>output_data</var>: will contain a private key PEM or DER encoded
<p><var>output_data_size</var>: holds the size of output_data (and will be
replaced by the actual size of parameters)
<p>This function will export the private key to a PKCS8 structure.
Currently only RSA keys can be exported since there is no documented
standard for other keys. If the flags do not
specify the encryption cipher, then the default 3DES (PBES2) will
be used.
<p>The <code>password</code> can be either ASCII or UTF-8 in the default PBES2
encryption schemas, or ASCII for the PKCS12 schemas.
<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>If the structure is PEM encoded, it will have a header
of "BEGIN ENCRYPTED PRIVATE KEY" or "BEGIN PRIVATE KEY" if
encryption is not used.
<p><strong>Return value:</strong> In case of failure a negative value will be
returned, and 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_privkey_export_rsa_raw</h4>
<p><a name="gnutls_005fx509_005fprivkey_005fexport_005frsa_005fraw"></a>
<div class="defun">
— Function: int <b>gnutls_x509_privkey_export_rsa_raw</b> (<var>gnutls_x509_privkey_t key, gnutls_datum_t * m, gnutls_datum_t * e, gnutls_datum_t * d, gnutls_datum_t * p, gnutls_datum_t * q, gnutls_datum_t * u</var>)<var><a name="index-gnutls_005fx509_005fprivkey_005fexport_005frsa_005fraw-365"></a></var><br>
<blockquote><p><var>key</var>: a structure that holds the rsa parameters
<p><var>m</var>: will hold the modulus
<p><var>e</var>: will hold the public exponent
<p><var>d</var>: will hold the private exponent
<p><var>p</var>: will hold the first prime (p)
<p><var>q</var>: will hold the second prime (q)
<p><var>u</var>: will hold the coefficient
<p>This function will export the RSA private key's parameters found in the given
structure. The new parameters will be allocated using
<code>gnutls_malloc()</code> and will be stored in the appropriate datum.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_privkey_export</h4>
<p><a name="gnutls_005fx509_005fprivkey_005fexport"></a>
<div class="defun">
— Function: int <b>gnutls_x509_privkey_export</b> (<var>gnutls_x509_privkey_t key, gnutls_x509_crt_fmt_t format, void * output_data, size_t * output_data_size</var>)<var><a name="index-gnutls_005fx509_005fprivkey_005fexport-366"></a></var><br>
<blockquote><p><var>key</var>: Holds the key
<p><var>format</var>: the format of output params. One of PEM or DER.
<p><var>output_data</var>: will contain a private key PEM or DER encoded
<p><var>output_data_size</var>: holds the size of output_data (and will be
replaced by the actual size of parameters)
<p>This function will export the private key to a PKCS1 structure for
RSA keys, or an integer sequence for DSA keys. The DSA keys are in
the same format with the parameters used by openssl.
<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>If the structure is PEM encoded, it will have a header
of "BEGIN RSA PRIVATE KEY".
<p><strong>Return value:</strong> In case of failure a negative value will be
returned, and 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_privkey_fix</h4>
<p><a name="gnutls_005fx509_005fprivkey_005ffix"></a>
<div class="defun">
— Function: int <b>gnutls_x509_privkey_fix</b> (<var>gnutls_x509_privkey_t key</var>)<var><a name="index-gnutls_005fx509_005fprivkey_005ffix-367"></a></var><br>
<blockquote><p><var>key</var>: Holds the key
<p>This function will recalculate the secondary parameters in a key.
In RSA keys, this can be the coefficient and exponent1,2.
<p><strong>Return value:</strong> In case of failure a negative value will be
returned, and 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_privkey_generate</h4>
<p><a name="gnutls_005fx509_005fprivkey_005fgenerate"></a>
<div class="defun">
— Function: int <b>gnutls_x509_privkey_generate</b> (<var>gnutls_x509_privkey_t key, gnutls_pk_algorithm_t algo, unsigned int bits, unsigned int flags</var>)<var><a name="index-gnutls_005fx509_005fprivkey_005fgenerate-368"></a></var><br>
<blockquote><p><var>key</var>: should contain a gnutls_x509_privkey_t structure
<p><var>algo</var>: is one of RSA or DSA.
<p><var>bits</var>: the size of the modulus
<p><var>flags</var>: unused for now. Must be 0.
<p>This function will generate a random private key. Note that
this function must be called on an empty private key.
<p>Returns 0 on success or a negative value on error.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_privkey_get_key_id</h4>
<p><a name="gnutls_005fx509_005fprivkey_005fget_005fkey_005fid"></a>
<div class="defun">
— Function: int <b>gnutls_x509_privkey_get_key_id</b> (<var>gnutls_x509_privkey_t key, unsigned int flags, unsigned char * output_data, size_t * output_data_size</var>)<var><a name="index-gnutls_005fx509_005fprivkey_005fget_005fkey_005fid-369"></a></var><br>
<blockquote><p><var>key</var>: Holds the key
<p><var>flags</var>: should be 0 for now
<p><var>output_data</var>: will contain the key ID
<p><var>output_data_size</var>: holds the size of output_data (and will be
replaced by the actual size of parameters)
<p>This function will return a unique ID the depends on the public key
parameters. This ID can be used in checking whether a certificate
corresponds to the given key.
<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><strong>Return value:</strong> In case of failure a negative value will be
returned, and 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_privkey_get_pk_algorithm</h4>
<p><a name="gnutls_005fx509_005fprivkey_005fget_005fpk_005falgorithm"></a>
<div class="defun">
— Function: int <b>gnutls_x509_privkey_get_pk_algorithm</b> (<var>gnutls_x509_privkey_t key</var>)<var><a name="index-gnutls_005fx509_005fprivkey_005fget_005fpk_005falgorithm-370"></a></var><br>
<blockquote><p><var>key</var>: should contain a gnutls_x509_privkey_t structure
<p>This function will return the public key algorithm of a private
key.
<p>Returns a member of the gnutls_pk_algorithm_t enumeration on success,
or a negative value on error.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_privkey_import_dsa_raw</h4>
<p><a name="gnutls_005fx509_005fprivkey_005fimport_005fdsa_005fraw"></a>
<div class="defun">
— Function: int <b>gnutls_x509_privkey_import_dsa_raw</b> (<var>gnutls_x509_privkey_t key, const gnutls_datum_t * p, const gnutls_datum_t * q, const gnutls_datum_t * g, const gnutls_datum_t * y, const gnutls_datum_t * x</var>)<var><a name="index-gnutls_005fx509_005fprivkey_005fimport_005fdsa_005fraw-371"></a></var><br>
<blockquote><p><var>key</var>: The structure to store the parsed key
<p><var>p</var>: holds the p
<p><var>q</var>: holds the q
<p><var>g</var>: holds the g
<p><var>y</var>: holds the y
<p><var>x</var>: holds the x
<p>This function will convert the given DSA raw parameters
to the native gnutls_x509_privkey_t format. The output will be stored in <code>key</code>.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_privkey_import_pkcs8</h4>
<p><a name="gnutls_005fx509_005fprivkey_005fimport_005fpkcs8"></a>
<div class="defun">
— Function: int <b>gnutls_x509_privkey_import_pkcs8</b> (<var>gnutls_x509_privkey_t key, const gnutls_datum_t * data, gnutls_x509_crt_fmt_t format, const char * password, unsigned int flags</var>)<var><a name="index-gnutls_005fx509_005fprivkey_005fimport_005fpkcs8-372"></a></var><br>
<blockquote><p><var>key</var>: The structure to store the parsed key
<p><var>data</var>: The DER or PEM encoded key.
<p><var>format</var>: One of DER or PEM
<p><var>password</var>: the password to decrypt the key (if it is encrypted).
<p><var>flags</var>: 0 if encrypted or GNUTLS_PKCS_PLAIN if not encrypted.
<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>key</code>.
Currently only RSA keys can be imported, and flags can only be used to indicate
an unencrypted key.
<p>The <code>password</code> can be either ASCII or UTF-8 in the default PBES2
encryption schemas, or ASCII for the PKCS12 schemas.
<p>If the Certificate is PEM encoded it should have a header of "ENCRYPTED PRIVATE KEY",
or "PRIVATE KEY". 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>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_privkey_import_rsa_raw</h4>
<p><a name="gnutls_005fx509_005fprivkey_005fimport_005frsa_005fraw"></a>
<div class="defun">
— Function: int <b>gnutls_x509_privkey_import_rsa_raw</b> (<var>gnutls_x509_privkey_t key, const gnutls_datum_t * m, const gnutls_datum_t * e, const gnutls_datum_t * d, const gnutls_datum_t * p, const gnutls_datum_t * q, const gnutls_datum_t * u</var>)<var><a name="index-gnutls_005fx509_005fprivkey_005fimport_005frsa_005fraw-373"></a></var><br>
<blockquote><p><var>key</var>: The structure to store the parsed key
<p><var>m</var>: holds the modulus
<p><var>e</var>: holds the public exponent
<p><var>d</var>: holds the private exponent
<p><var>p</var>: holds the first prime (p)
<p><var>q</var>: holds the second prime (q)
<p><var>u</var>: holds the coefficient
<p>This function will convert the given RSA raw parameters
to the native gnutls_x509_privkey_t format. The output will be stored in <code>key</code>.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_privkey_import</h4>
<p><a name="gnutls_005fx509_005fprivkey_005fimport"></a>
<div class="defun">
— Function: int <b>gnutls_x509_privkey_import</b> (<var>gnutls_x509_privkey_t key, const gnutls_datum_t * data, gnutls_x509_crt_fmt_t format</var>)<var><a name="index-gnutls_005fx509_005fprivkey_005fimport-374"></a></var><br>
<blockquote><p><var>key</var>: The structure to store the parsed key
<p><var>data</var>: The DER or PEM encoded certificate.
<p><var>format</var>: One of DER or PEM
<p>This function will convert the given DER or PEM encoded key
to the native gnutls_x509_privkey_t format. The output will be stored in <code>key</code> .
<p>If the key is PEM encoded it should have a header of "RSA PRIVATE KEY", or
"DSA PRIVATE KEY".
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_privkey_init</h4>
<p><a name="gnutls_005fx509_005fprivkey_005finit"></a>
<div class="defun">
— Function: int <b>gnutls_x509_privkey_init</b> (<var>gnutls_x509_privkey_t * key</var>)<var><a name="index-gnutls_005fx509_005fprivkey_005finit-375"></a></var><br>
<blockquote><p><var>key</var>: The structure to be initialized
<p>This function will initialize an private key structure.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_privkey_sign_data</h4>
<p><a name="gnutls_005fx509_005fprivkey_005fsign_005fdata"></a>
<div class="defun">
— Function: int <b>gnutls_x509_privkey_sign_data</b> (<var>gnutls_x509_privkey_t key, gnutls_digest_algorithm_t digest, unsigned int flags, const gnutls_datum_t * data, void * signature, size_t * signature_size</var>)<var><a name="index-gnutls_005fx509_005fprivkey_005fsign_005fdata-376"></a></var><br>
<blockquote><p><var>key</var>: Holds the key
<p><var>digest</var>: should be MD5 or SHA1
<p><var>flags</var>: should be 0 for now
<p><var>data</var>: holds the data to be signed
<p><var>signature</var>: will contain the signature
<p><var>signature_size</var>: holds the size of signature (and will be replaced
by the new size)
<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>If the buffer provided is not long enough to hold the output, then
*signature_size is updated and GNUTLS_E_SHORT_MEMORY_BUFFER will
be returned.
<p>In case of failure a negative value will be returned, and
0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_privkey_verify_data</h4>
<p><a name="gnutls_005fx509_005fprivkey_005fverify_005fdata"></a>
<div class="defun">
— Function: int <b>gnutls_x509_privkey_verify_data</b> (<var>gnutls_x509_privkey_t key, unsigned int flags, const gnutls_datum_t * data, const gnutls_datum_t * signature</var>)<var><a name="index-gnutls_005fx509_005fprivkey_005fverify_005fdata-377"></a></var><br>
<blockquote><p><var>key</var>: Holds the key
<p><var>flags</var>: should be 0 for now
<p><var>data</var>: holds the data to be signed
<p><var>signature</var>: contains the signature
<p>This function will verify the given signed data, using the parameters in the
private key.
<p>In case of a verification failure 0 is returned, and
1 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_rdn_get_by_oid</h4>
<p><a name="gnutls_005fx509_005frdn_005fget_005fby_005foid"></a>
<div class="defun">
— Function: int <b>gnutls_x509_rdn_get_by_oid</b> (<var>const gnutls_datum_t * idn, const char * oid, int indx, unsigned int raw_flag, void * buf, size_t * sizeof_buf</var>)<var><a name="index-gnutls_005fx509_005frdn_005fget_005fby_005foid-378"></a></var><br>
<blockquote><p><var>idn</var>: should contain a DER encoded RDN sequence
<p><var>oid</var>: an Object Identifier
<p><var>indx</var>: In case multiple same OIDs exist in the RDN indicates which
to send. Use 0 for the first one.
<p><var>raw_flag</var>: If non zero then the raw DER data are returned.
<p><var>buf</var>: a pointer to a structure to hold the peer's name
<p><var>sizeof_buf</var>: holds the size of <code>buf</code>
<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 RFC2253.
<p>Returns GNUTLS_E_SHORT_MEMORY_BUFFER and updates *sizeof_buf if
the provided buffer is not long enough, and 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_rdn_get_oid</h4>
<p><a name="gnutls_005fx509_005frdn_005fget_005foid"></a>
<div class="defun">
— Function: int <b>gnutls_x509_rdn_get_oid</b> (<var>const gnutls_datum_t * idn, int indx, void * buf, size_t * sizeof_buf</var>)<var><a name="index-gnutls_005fx509_005frdn_005fget_005foid-379"></a></var><br>
<blockquote><p><var>idn</var>: should contain a DER encoded RDN sequence
<p><var>indx</var>: Indicates which OID to return. Use 0 for the first one.
<p>This function will return the specified Object identifier, of the
RDN sequence.
<p>Returns GNUTLS_E_SHORT_MEMORY_BUFFER and updates *sizeof_buf if
the provided buffer is not long enough, and 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_x509_rdn_get</h4>
<p><a name="gnutls_005fx509_005frdn_005fget"></a>
<div class="defun">
— Function: int <b>gnutls_x509_rdn_get</b> (<var>const gnutls_datum_t * idn, char * buf, size_t * sizeof_buf</var>)<var><a name="index-gnutls_005fx509_005frdn_005fget-380"></a></var><br>
<blockquote><p><var>idn</var>: should contain a DER encoded RDN sequence
<p><var>buf</var>: a pointer to a structure to hold the peer's name
<p><var>sizeof_buf</var>: holds the size of <code>buf</code>
<p>This function will return the name of the given RDN sequence. The
name will be in the form "C=xxxx,O=yyyy,CN=zzzz" as described in
RFC2253.
<p>If the provided buffer is not long enough, returns
GNUTLS_E_SHORT_MEMORY_BUFFER and *sizeof_buf will be updated. On
success 0 is returned.
</p></blockquote></div>
<div class="node">
<p><hr>
<a name="GnuTLS-extra-functions"></a>
<a name="GnuTLS_002dextra-functions"></a>
Next: <a rel="next" accesskey="n" href="#OpenPGP-functions">OpenPGP functions</a>,
Previous: <a rel="previous" accesskey="p" href="#X_002e509-certificate-functions">X.509 certificate functions</a>,
Up: <a rel="up" accesskey="u" href="#Function-reference">Function reference</a>
</div>
<h3 class="section">9.3 <acronym>GnuTLS-extra</acronym> functions</h3>
<p><a name="index-g_t_0040acronym_007bGnuTLS_002dextra_007d-functions-381"></a>
These functions are only available in the GPL version of the library
called <code>gnutls-extra</code>. The prototypes for this library lie in
<samp><span class="file">gnutls/extra.h</span></samp>.
<h4 class="subheading">gnutls_extra_check_version</h4>
<p><a name="gnutls_005fextra_005fcheck_005fversion"></a>
<div class="defun">
— Function: const char * <b>gnutls_extra_check_version</b> (<var>const char * req_version</var>)<var><a name="index-gnutls_005fextra_005fcheck_005fversion-382"></a></var><br>
<blockquote><p><var>req_version</var>: the version to check
<p>Check that the version of the gnutls-extra library is at minimum
the requested one and return the version string; return NULL if the
condition is not satisfied. If a NULL is passed to this function,
no check is done, but the version string is simply returned.
</p></blockquote></div>
<h4 class="subheading">gnutls_global_init_extra</h4>
<p><a name="gnutls_005fglobal_005finit_005fextra"></a>
<div class="defun">
— Function: int <b>gnutls_global_init_extra</b> (<var> void</var>)<var><a name="index-gnutls_005fglobal_005finit_005fextra-383"></a></var><br>
<blockquote>
<p>This function initializes the global state of gnutls-extra library to defaults.
Returns zero on success.
<p>Note that <code>gnutls_global_init()</code> has to be called before this function.
If this function is not called then the gnutls-extra library will not
be usable.
</p></blockquote></div>
<div class="node">
<p><hr>
<a name="OpenPGP-functions"></a>
Next: <a rel="next" accesskey="n" href="#TLS-Inner-Application-_0028TLS_002fIA_0029-functions">TLS Inner Application (TLS/IA) functions</a>,
Previous: <a rel="previous" accesskey="p" href="#GnuTLS_002dextra-functions">GnuTLS-extra functions</a>,
Up: <a rel="up" accesskey="u" href="#Function-reference">Function reference</a>
</div>
<h3 class="section">9.4 <acronym>OpenPGP</acronym> functions</h3>
<p><a name="index-g_t_0040acronym_007bOpenPGP_007d-functions-384"></a><a name="sec_003aopenpgpapi"></a>
<p>The following functions are to be used for <acronym>OpenPGP</acronym>
certificate handling. Their prototypes lie in
<samp><span class="file">gnutls/openpgp.h</span></samp>. You need to link with <samp><span class="file">libgnutls-extra</span></samp>
to be able to use these functions (see <a href="#GnuTLS_002dextra-functions">GnuTLS-extra functions</a>).
<h4 class="subheading">gnutls_certificate_set_openpgp_key_file</h4>
<p><a name="gnutls_005fcertificate_005fset_005fopenpgp_005fkey_005ffile"></a>
<div class="defun">
— Function: int <b>gnutls_certificate_set_openpgp_key_file</b> (<var>gnutls_certificate_credentials_t res, const char * certfile, const char * keyfile</var>)<var><a name="index-gnutls_005fcertificate_005fset_005fopenpgp_005fkey_005ffile-385"></a></var><br>
<blockquote><p><var>res</var>: the destination context to save the data.
<p><var>certfile</var>: the file that contains the public key.
<p><var>keyfile</var>: the file that contains the secret key.
<p>This funtion is used to load OpenPGP keys into the GnuTLS credentials structure.
It doesn't matter whether the keys are armored or but, but the files
should only contain one key which should not be encrypted.
</p></blockquote></div>
<h4 class="subheading">gnutls_certificate_set_openpgp_key_mem</h4>
<p><a name="gnutls_005fcertificate_005fset_005fopenpgp_005fkey_005fmem"></a>
<div class="defun">
— Function: int <b>gnutls_certificate_set_openpgp_key_mem</b> (<var>gnutls_certificate_credentials_t res, const gnutls_datum_t * cert, const gnutls_datum_t * key</var>)<var><a name="index-gnutls_005fcertificate_005fset_005fopenpgp_005fkey_005fmem-386"></a></var><br>
<blockquote><p><var>res</var>: the destination context to save the data.
<p><var>cert</var>: the datum that contains the public key.
<p><var>key</var>: the datum that contains the secret key.
<p>This funtion is used to load OpenPGP keys into the GnuTLS credential structure.
It doesn't matter whether the keys are armored or but, but the files
should only contain one key which should not be encrypted.
</p></blockquote></div>
<h4 class="subheading">gnutls_certificate_set_openpgp_keyring_file</h4>
<p><a name="gnutls_005fcertificate_005fset_005fopenpgp_005fkeyring_005ffile"></a>
<div class="defun">
— Function: int <b>gnutls_certificate_set_openpgp_keyring_file</b> (<var>gnutls_certificate_credentials_t c, const char * file</var>)<var><a name="index-gnutls_005fcertificate_005fset_005fopenpgp_005fkeyring_005ffile-387"></a></var><br>
<blockquote><p><var>c</var>: A certificate credentials structure
<p><var>file</var>: filename of the keyring.
<p>The function is used to set keyrings that will be used internally
by various OpenPGP functions. For example to find a key when it
is needed for an operations. The keyring will also be used at the
verification functions.
</p></blockquote></div>
<h4 class="subheading">gnutls_certificate_set_openpgp_keyring_mem</h4>
<p><a name="gnutls_005fcertificate_005fset_005fopenpgp_005fkeyring_005fmem"></a>
<div class="defun">
— Function: int <b>gnutls_certificate_set_openpgp_keyring_mem</b> (<var>gnutls_certificate_credentials_t c, const opaque * data, size_t dlen</var>)<var><a name="index-gnutls_005fcertificate_005fset_005fopenpgp_005fkeyring_005fmem-388"></a></var><br>
<blockquote><p><var>c</var>: A certificate credentials structure
<p><var>data</var>: buffer with keyring data.
<p><var>dlen</var>: length of data buffer.
<p>The function is used to set keyrings that will be used internally
by various OpenPGP functions. For example to find a key when it
is needed for an operations. The keyring will also be used at the
verification functions.
</p></blockquote></div>
<h4 class="subheading">gnutls_certificate_set_openpgp_keyserver</h4>
<p><a name="gnutls_005fcertificate_005fset_005fopenpgp_005fkeyserver"></a>
<div class="defun">
— Function: int <b>gnutls_certificate_set_openpgp_keyserver</b> (<var>gnutls_certificate_credentials_t res, const char * keyserver, int port</var>)<var><a name="index-gnutls_005fcertificate_005fset_005fopenpgp_005fkeyserver-389"></a></var><br>
<blockquote><p><var>res</var>: the destination context to save the data.
<p><var>keyserver</var>: is the key server address
<p><var>port</var>: is the key server port to connect to
<p>This funtion will set a key server for use with openpgp keys. This
key server will only be used if the peer sends a key fingerprint instead
of a key in the handshake. Using a key server may delay the handshake
process.
</p></blockquote></div>
<h4 class="subheading">gnutls_certificate_set_openpgp_key</h4>
<p><a name="gnutls_005fcertificate_005fset_005fopenpgp_005fkey"></a>
<div class="defun">
— Function: int <b>gnutls_certificate_set_openpgp_key</b> (<var>gnutls_certificate_credentials_t res, gnutls_openpgp_key_t key, gnutls_openpgp_privkey_t pkey</var>)<var><a name="index-gnutls_005fcertificate_005fset_005fopenpgp_005fkey-390"></a></var><br>
<blockquote><p><var>res</var>: is an <code>gnutls_certificate_credentials_t</code> structure.
<p><var>key</var>: contains an openpgp public key
<p><var>pkey</var>: is an openpgp private key
<p>This function sets a certificate/private key pair in the
gnutls_certificate_credentials_t structure. This function may be called
more than once (in case multiple keys/certificates exist for the
server).
</p></blockquote></div>
<h4 class="subheading">gnutls_certificate_set_openpgp_trustdb</h4>
<p><a name="gnutls_005fcertificate_005fset_005fopenpgp_005ftrustdb"></a>
<div class="defun">
— Function: int <b>gnutls_certificate_set_openpgp_trustdb</b> (<var>gnutls_certificate_credentials_t res, const char * trustdb</var>)<var><a name="index-gnutls_005fcertificate_005fset_005fopenpgp_005ftrustdb-391"></a></var><br>
<blockquote><p><var>res</var>: the destination context to save the data.
<p><var>trustdb</var>: is the trustdb filename
<p>This funtion will set a GnuPG trustdb which will be used in key
verification functions. Only version 3 trustdb files are supported.
</p></blockquote></div>
<h4 class="subheading">gnutls_openpgp_key_check_hostname</h4>
<p><a name="gnutls_005fopenpgp_005fkey_005fcheck_005fhostname"></a>
<div class="defun">
— Function: int <b>gnutls_openpgp_key_check_hostname</b> (<var>gnutls_openpgp_key_t key, const char * hostname</var>)<var><a name="index-gnutls_005fopenpgp_005fkey_005fcheck_005fhostname-392"></a></var><br>
<blockquote><p><var>key</var>: should contain an gnutls_openpgp_key_t structure
<p><var>hostname</var>: A null terminated string that contains a DNS name
<p>This function will check if the given key's owner matches
the given hostname. This is a basic implementation of the matching
described in RFC2818 (HTTPS), which takes into account wildcards.
<p>Returns non zero on success, and zero on failure.
</p></blockquote></div>
<h4 class="subheading">gnutls_openpgp_key_deinit</h4>
<p><a name="gnutls_005fopenpgp_005fkey_005fdeinit"></a>
<div class="defun">
— Function: void <b>gnutls_openpgp_key_deinit</b> (<var>gnutls_openpgp_key_t key</var>)<var><a name="index-gnutls_005fopenpgp_005fkey_005fdeinit-393"></a></var><br>
<blockquote><p><var>key</var>: The structure to be initialized
<p>This function will deinitialize a key structure.
</p></blockquote></div>
<h4 class="subheading">gnutls_openpgp_key_export</h4>
<p><a name="gnutls_005fopenpgp_005fkey_005fexport"></a>
<div class="defun">
— Function: int <b>gnutls_openpgp_key_export</b> (<var>gnutls_openpgp_key_t key, gnutls_openpgp_key_fmt_t format, void * output_data, size_t * output_data_size</var>)<var><a name="index-gnutls_005fopenpgp_005fkey_005fexport-394"></a></var><br>
<blockquote><p><var>key</var>: Holds the key.
<p><var>format</var>: One of gnutls_openpgp_key_fmt_t elements.
<p><var>output_data</var>: will contain the key base64 encoded or raw
<p><var>output_data_size</var>: holds the size of output_data (and will be replaced by the actual size of parameters)
<p>This function will convert the given key to RAW or Base64 format.
If the buffer provided is not long enough to hold the output, then
GNUTLS_E_SHORT_MEMORY_BUFFER will be returned.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_openpgp_key_get_creation_time</h4>
<p><a name="gnutls_005fopenpgp_005fkey_005fget_005fcreation_005ftime"></a>
<div class="defun">
— Function: time_t <b>gnutls_openpgp_key_get_creation_time</b> (<var>gnutls_openpgp_key_t key</var>)<var><a name="index-gnutls_005fopenpgp_005fkey_005fget_005fcreation_005ftime-395"></a></var><br>
<blockquote><p><var>key</var>: the structure that contains the OpenPGP public key.
<p>Returns the timestamp when the OpenPGP key was created.
</p></blockquote></div>
<h4 class="subheading">gnutls_openpgp_key_get_expiration_time</h4>
<p><a name="gnutls_005fopenpgp_005fkey_005fget_005fexpiration_005ftime"></a>
<div class="defun">
— Function: time_t <b>gnutls_openpgp_key_get_expiration_time</b> (<var>gnutls_openpgp_key_t key</var>)<var><a name="index-gnutls_005fopenpgp_005fkey_005fget_005fexpiration_005ftime-396"></a></var><br>
<blockquote><p><var>key</var>: the structure that contains the OpenPGP public key.
<p>Returns the time when the OpenPGP key expires. A value of '0' means
that the key doesn't expire at all.
</p></blockquote></div>
<h4 class="subheading">gnutls_openpgp_key_get_fingerprint</h4>
<p><a name="gnutls_005fopenpgp_005fkey_005fget_005ffingerprint"></a>
<div class="defun">
— Function: int <b>gnutls_openpgp_key_get_fingerprint</b> (<var>gnutls_openpgp_key_t key, void * fpr, size_t * fprlen</var>)<var><a name="index-gnutls_005fopenpgp_005fkey_005fget_005ffingerprint-397"></a></var><br>
<blockquote><p><var>key</var>: the raw data that contains the OpenPGP public key.
<p><var>fpr</var>: the buffer to save the fingerprint.
<p><var>fprlen</var>: the integer to save the length of the fingerprint.
<p>Returns the fingerprint of the OpenPGP key. Depends on the algorithm,
the fingerprint can be 16 or 20 bytes.
</p></blockquote></div>
<h4 class="subheading">gnutls_openpgp_key_get_id</h4>
<p><a name="gnutls_005fopenpgp_005fkey_005fget_005fid"></a>
<div class="defun">
— Function: int <b>gnutls_openpgp_key_get_id</b> (<var>gnutls_openpgp_key_t key, unsigned char keyid[8]</var>)<var><a name="index-gnutls_005fopenpgp_005fkey_005fget_005fid-398"></a></var><br>
<blockquote><p><var>key</var>: the structure that contains the OpenPGP public key.
<p>Returns the 64-bit keyID of the OpenPGP key.
</p></blockquote></div>
<h4 class="subheading">gnutls_openpgp_key_get_key_usage</h4>
<p><a name="gnutls_005fopenpgp_005fkey_005fget_005fkey_005fusage"></a>
<div class="defun">
— Function: int <b>gnutls_openpgp_key_get_key_usage</b> (<var>gnutls_openpgp_key_t key, unsigned int * key_usage</var>)<var><a name="index-gnutls_005fopenpgp_005fkey_005fget_005fkey_005fusage-399"></a></var><br>
<blockquote><p><var>key</var>: should contain a gnutls_openpgp_key_t structure
<p><var>key_usage</var>: where the key usage bits will be stored
<p>This function will return certificate's key usage, by checking the
key algorithm. The key usage value will ORed values of the:
GNUTLS_KEY_DIGITAL_SIGNATURE, GNUTLS_KEY_KEY_ENCIPHERMENT.
<p>A negative value may be returned in case of parsing error.
</p></blockquote></div>
<h4 class="subheading">gnutls_openpgp_key_get_name</h4>
<p><a name="gnutls_005fopenpgp_005fkey_005fget_005fname"></a>
<div class="defun">
— Function: int <b>gnutls_openpgp_key_get_name</b> (<var>gnutls_openpgp_key_t key, int idx, char * buf, size_t * sizeof_buf</var>)<var><a name="index-gnutls_005fopenpgp_005fkey_005fget_005fname-400"></a></var><br>
<blockquote><p><var>key</var>: the structure that contains the OpenPGP public key.
<p><var>idx</var>: the index of the ID to extract
<p><var>buf</var>: a pointer to a structure to hold the name
<p><var>sizeof_buf</var>: holds the size of 'buf'
<p>Extracts the userID from the parsed OpenPGP key.
<p>Returns 0 on success, and GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE
if the index of the ID does not exist.
</p></blockquote></div>
<h4 class="subheading">gnutls_openpgp_key_get_pk_algorithm</h4>
<p><a name="gnutls_005fopenpgp_005fkey_005fget_005fpk_005falgorithm"></a>
<div class="defun">
— Function: int <b>gnutls_openpgp_key_get_pk_algorithm</b> (<var>gnutls_openpgp_key_t key, unsigned int * bits</var>)<var><a name="index-gnutls_005fopenpgp_005fkey_005fget_005fpk_005falgorithm-401"></a></var><br>
<blockquote><p><var>key</var>: is an OpenPGP key
<p><var>bits</var>: if bits is non null it will hold the size of the parameters' in bits
<p>This function will return the public key algorithm of an OpenPGP
certificate.
<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>Returns a member of the GNUTLS_PKAlgorithm enumeration on success,
or a negative value on error.
</p></blockquote></div>
<h4 class="subheading">gnutls_openpgp_key_get_version</h4>
<p><a name="gnutls_005fopenpgp_005fkey_005fget_005fversion"></a>
<div class="defun">
— Function: int <b>gnutls_openpgp_key_get_version</b> (<var>gnutls_openpgp_key_t key</var>)<var><a name="index-gnutls_005fopenpgp_005fkey_005fget_005fversion-402"></a></var><br>
<blockquote><p><var>key</var>: the structure that contains the OpenPGP public key.
<p>Extract the version of the OpenPGP key.
</p></blockquote></div>
<h4 class="subheading">gnutls_openpgp_key_import</h4>
<p><a name="gnutls_005fopenpgp_005fkey_005fimport"></a>
<div class="defun">
— Function: int <b>gnutls_openpgp_key_import</b> (<var>gnutls_openpgp_key_t key, const gnutls_datum_t * data, gnutls_openpgp_key_fmt_t format</var>)<var><a name="index-gnutls_005fopenpgp_005fkey_005fimport-403"></a></var><br>
<blockquote><p><var>key</var>: The structure to store the parsed key.
<p><var>data</var>: The RAW or BASE64 encoded key.
<p><var>format</var>: One of gnutls_openpgp_key_fmt_t elements.
<p>This function will convert the given RAW or Base64 encoded key
to the native gnutls_openpgp_key_t format. The output will be stored in 'key'.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_openpgp_key_init</h4>
<p><a name="gnutls_005fopenpgp_005fkey_005finit"></a>
<div class="defun">
— Function: int <b>gnutls_openpgp_key_init</b> (<var>gnutls_openpgp_key_t * key</var>)<var><a name="index-gnutls_005fopenpgp_005fkey_005finit-404"></a></var><br>
<blockquote><p><var>key</var>: The structure to be initialized
<p>This function will initialize an OpenPGP key structure.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_openpgp_key_to_xml</h4>
<p><a name="gnutls_005fopenpgp_005fkey_005fto_005fxml"></a>
<div class="defun">
— Function: int <b>gnutls_openpgp_key_to_xml</b> (<var>gnutls_openpgp_key_t key, gnutls_datum_t * xmlkey, int ext</var>)<var><a name="index-gnutls_005fopenpgp_005fkey_005fto_005fxml-405"></a></var><br>
<blockquote><p><var>xmlkey</var>: he datum struct to store the XML result.
<p><var>ext</var>: extension mode (1/0), 1 means include key signatures and key data.
<p>This function will return the all OpenPGP key information encapsulated as
a XML string.
</p></blockquote></div>
<h4 class="subheading">gnutls_openpgp_key_verify_ring</h4>
<p><a name="gnutls_005fopenpgp_005fkey_005fverify_005fring"></a>
<div class="defun">
— Function: int <b>gnutls_openpgp_key_verify_ring</b> (<var>gnutls_openpgp_key_t key, gnutls_openpgp_keyring_t keyring, unsigned int flags, unsigned int * verify</var>)<var><a name="index-gnutls_005fopenpgp_005fkey_005fverify_005fring-406"></a></var><br>
<blockquote><p><var>key</var>: the structure that holds the key.
<p><var>keyring</var>: holds the keyring to check against
<p><var>flags</var>: unused (should be 0)
<p><var>verify</var>: will hold the certificate verification output.
<p>Verify all signatures in the key, using the given set of keys (keyring).
<p>The key verification output will be put in <code>verify</code> and will be
one or more of the gnutls_certificate_status_t enumerated elements bitwise or'd.
<p><strong>GNUTLS_CERT_INVALID:</strong> A signature on the key is invalid.
<p><strong>GNUTLS_CERT_REVOKED:</strong> The key has been revoked.
<p>Note that this function does not verify using any "web of
trust". You may use GnuPG for that purpose, or any other external
PGP application.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_openpgp_key_verify_self</h4>
<p><a name="gnutls_005fopenpgp_005fkey_005fverify_005fself"></a>
<div class="defun">
— Function: int <b>gnutls_openpgp_key_verify_self</b> (<var>gnutls_openpgp_key_t key, unsigned int flags, unsigned int * verify</var>)<var><a name="index-gnutls_005fopenpgp_005fkey_005fverify_005fself-407"></a></var><br>
<blockquote><p><var>key</var>: the structure that holds the key.
<p><var>flags</var>: unused (should be 0)
<p><var>verify</var>: will hold the key verification output.
<p>Verifies the self signature in the key.
The key verification output will be put in <code>verify</code> and will be
one or more of the gnutls_certificate_status_t enumerated elements bitwise or'd.
<p><strong>GNUTLS_CERT_INVALID:</strong> The self signature on the key is invalid.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_openpgp_key_verify_trustdb</h4>
<p><a name="gnutls_005fopenpgp_005fkey_005fverify_005ftrustdb"></a>
<div class="defun">
— Function: int <b>gnutls_openpgp_key_verify_trustdb</b> (<var>gnutls_openpgp_key_t key, gnutls_openpgp_trustdb_t trustdb, unsigned int flags, unsigned int * verify</var>)<var><a name="index-gnutls_005fopenpgp_005fkey_005fverify_005ftrustdb-408"></a></var><br>
<blockquote><p><var>key</var>: the structure that holds the key.
<p><var>trustdb</var>: holds the trustdb to check against
<p><var>flags</var>: unused (should be 0)
<p><var>verify</var>: will hold the certificate verification output.
<p>Checks if the key is revoked or disabled, in the trustdb.
The verification output will be put in <code>verify</code> and will be
one or more of the gnutls_certificate_status_t enumerated elements bitwise or'd.
<p><strong>GNUTLS_CERT_INVALID:</strong> A signature on the key is invalid.
<p><strong>GNUTLS_CERT_REVOKED:</strong> The key has been revoked.
<p>Note that this function does not verify using any "web of
trust". You may use GnuPG for that purpose, or any other external
PGP application.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_openpgp_keyring_check_id</h4>
<p><a name="gnutls_005fopenpgp_005fkeyring_005fcheck_005fid"></a>
<div class="defun">
— Function: int <b>gnutls_openpgp_keyring_check_id</b> (<var>gnutls_openpgp_keyring_t ring, const unsigned char keyid[8], unsigned int flags</var>)<var><a name="index-gnutls_005fopenpgp_005fkeyring_005fcheck_005fid-409"></a></var><br>
<blockquote><p><var>ring</var>: holds the keyring to check against
<p><var>flags</var>: unused (should be 0)
<p>Check if a given key ID exists in the keyring.
<p>Returns 0 on success (if keyid exists) and a negative error code
on failure.
</p></blockquote></div>
<h4 class="subheading">gnutls_openpgp_keyring_deinit</h4>
<p><a name="gnutls_005fopenpgp_005fkeyring_005fdeinit"></a>
<div class="defun">
— Function: void <b>gnutls_openpgp_keyring_deinit</b> (<var>gnutls_openpgp_keyring_t keyring</var>)<var><a name="index-gnutls_005fopenpgp_005fkeyring_005fdeinit-410"></a></var><br>
<blockquote><p><var>keyring</var>: The structure to be initialized
<p>This function will deinitialize a CRL structure.
</p></blockquote></div>
<h4 class="subheading">gnutls_openpgp_keyring_import</h4>
<p><a name="gnutls_005fopenpgp_005fkeyring_005fimport"></a>
<div class="defun">
— Function: int <b>gnutls_openpgp_keyring_import</b> (<var>gnutls_openpgp_keyring_t keyring, const gnutls_datum_t * data, gnutls_openpgp_key_fmt_t format</var>)<var><a name="index-gnutls_005fopenpgp_005fkeyring_005fimport-411"></a></var><br>
<blockquote><p><var>keyring</var>: The structure to store the parsed key.
<p><var>data</var>: The RAW or BASE64 encoded keyring.
<p><var>format</var>: One of gnutls_openpgp_keyring_fmt elements.
<p>This function will convert the given RAW or Base64 encoded keyring
to the native gnutls_openpgp_keyring_t format. The output will be stored in 'keyring'.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_openpgp_keyring_init</h4>
<p><a name="gnutls_005fopenpgp_005fkeyring_005finit"></a>
<div class="defun">
— Function: int <b>gnutls_openpgp_keyring_init</b> (<var>gnutls_openpgp_keyring_t * keyring</var>)<var><a name="index-gnutls_005fopenpgp_005fkeyring_005finit-412"></a></var><br>
<blockquote><p><var>keyring</var>: The structure to be initialized
<p>This function will initialize an OpenPGP keyring structure.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_openpgp_privkey_deinit</h4>
<p><a name="gnutls_005fopenpgp_005fprivkey_005fdeinit"></a>
<div class="defun">
— Function: void <b>gnutls_openpgp_privkey_deinit</b> (<var>gnutls_openpgp_privkey_t key</var>)<var><a name="index-gnutls_005fopenpgp_005fprivkey_005fdeinit-413"></a></var><br>
<blockquote><p><var>key</var>: The structure to be initialized
<p>This function will deinitialize a key structure.
</p></blockquote></div>
<h4 class="subheading">gnutls_openpgp_privkey_get_pk_algorithm</h4>
<p><a name="gnutls_005fopenpgp_005fprivkey_005fget_005fpk_005falgorithm"></a>
<div class="defun">
— Function: int <b>gnutls_openpgp_privkey_get_pk_algorithm</b> (<var>gnutls_openpgp_privkey_t key, unsigned int * bits</var>)<var><a name="index-gnutls_005fopenpgp_005fprivkey_005fget_005fpk_005falgorithm-414"></a></var><br>
<blockquote><p><var>key</var>: is an OpenPGP key
<p><var>bits</var>: if bits is non null it will hold the size of the parameters' in bits
<p>This function will return the public key algorithm of an OpenPGP
certificate.
<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>Returns a member of the GNUTLS_PKAlgorithm enumeration on success,
or a negative value on error.
</p></blockquote></div>
<h4 class="subheading">gnutls_openpgp_privkey_import</h4>
<p><a name="gnutls_005fopenpgp_005fprivkey_005fimport"></a>
<div class="defun">
— Function: int <b>gnutls_openpgp_privkey_import</b> (<var>gnutls_openpgp_privkey_t key, const gnutls_datum_t * data, gnutls_openpgp_key_fmt_t format, const char * pass, unsigned int flags</var>)<var><a name="index-gnutls_005fopenpgp_005fprivkey_005fimport-415"></a></var><br>
<blockquote><p><var>key</var>: The structure to store the parsed key.
<p><var>data</var>: The RAW or BASE64 encoded key.
<p><var>format</var>: One of gnutls_openpgp_key_fmt_t elements.
<p><var>pass</var>: Unused for now
<p><var>flags</var>: should be zero
<p>This function will convert the given RAW or Base64 encoded key
to the native gnutls_openpgp_privkey_t format. The output will be stored in 'key'.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_openpgp_privkey_init</h4>
<p><a name="gnutls_005fopenpgp_005fprivkey_005finit"></a>
<div class="defun">
— Function: int <b>gnutls_openpgp_privkey_init</b> (<var>gnutls_openpgp_privkey_t * key</var>)<var><a name="index-gnutls_005fopenpgp_005fprivkey_005finit-416"></a></var><br>
<blockquote><p><var>key</var>: The structure to be initialized
<p>This function will initialize an OpenPGP key structure.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_openpgp_set_recv_key_function</h4>
<p><a name="gnutls_005fopenpgp_005fset_005frecv_005fkey_005ffunction"></a>
<div class="defun">
— Function: void <b>gnutls_openpgp_set_recv_key_function</b> (<var>gnutls_session_t session, gnutls_openpgp_recv_key_func func</var>)<var><a name="index-gnutls_005fopenpgp_005fset_005frecv_005fkey_005ffunction-417"></a></var><br>
<blockquote><p><var>session</var>: a TLS session
<p><var>func</var>: the callback
<p>This funtion will set a key retrieval function for OpenPGP keys. This
callback is only useful in server side, and will be used if the peer
sent a key fingerprint instead of a full key.
</p></blockquote></div>
<h4 class="subheading">gnutls_openpgp_trustdb_deinit</h4>
<p><a name="gnutls_005fopenpgp_005ftrustdb_005fdeinit"></a>
<div class="defun">
— Function: void <b>gnutls_openpgp_trustdb_deinit</b> (<var>gnutls_openpgp_trustdb_t trustdb</var>)<var><a name="index-gnutls_005fopenpgp_005ftrustdb_005fdeinit-418"></a></var><br>
<blockquote><p><var>trustdb</var>: The structure to be initialized
<p>This function will deinitialize a CRL structure.
</p></blockquote></div>
<h4 class="subheading">gnutls_openpgp_trustdb_import_file</h4>
<p><a name="gnutls_005fopenpgp_005ftrustdb_005fimport_005ffile"></a>
<div class="defun">
— Function: int <b>gnutls_openpgp_trustdb_import_file</b> (<var>gnutls_openpgp_trustdb_t trustdb, const char * file</var>)<var><a name="index-gnutls_005fopenpgp_005ftrustdb_005fimport_005ffile-419"></a></var><br>
<blockquote><p><var>trustdb</var>: The structure to store the parsed key.
<p><var>file</var>: The file that holds the trustdb.
<p>This function will convert the given RAW or Base64 encoded trustdb
to the native gnutls_openpgp_trustdb_t format. The output will be stored in 'trustdb'.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_openpgp_trustdb_init</h4>
<p><a name="gnutls_005fopenpgp_005ftrustdb_005finit"></a>
<div class="defun">
— Function: int <b>gnutls_openpgp_trustdb_init</b> (<var>gnutls_openpgp_trustdb_t * trustdb</var>)<var><a name="index-gnutls_005fopenpgp_005ftrustdb_005finit-420"></a></var><br>
<blockquote><p><var>trustdb</var>: The structure to be initialized
<p>This function will initialize an OpenPGP trustdb structure.
<p>Returns 0 on success.
</p></blockquote></div>
<div class="node">
<p><hr>
<a name="TLS-Inner-Application-(TLS%2fIA)-functions"></a>
<a name="TLS-Inner-Application-_0028TLS_002fIA_0029-functions"></a>
Next: <a rel="next" accesskey="n" href="#Error-codes-and-descriptions">Error codes and descriptions</a>,
Previous: <a rel="previous" accesskey="p" href="#OpenPGP-functions">OpenPGP functions</a>,
Up: <a rel="up" accesskey="u" href="#Function-reference">Function reference</a>
</div>
<h3 class="section">9.5 <acronym>TLS</acronym> Inner Application (<acronym>TLS/IA</acronym>) functions</h3>
<p><a name="index-g_t_0040acronym_007bTLS_007d-Inner-Application-_0028_0040acronym_007bTLS_002fIA_007d_0029-functions-421"></a><a name="index-Inner-Application-_0028_0040acronym_007bTLS_002fIA_007d_0029-functions-422"></a>
The following functions are used for <acronym>TLS</acronym> Inner Application
(<acronym>TLS/IA</acronym>). Their prototypes lie in <samp><span class="file">gnutls/extra.h</span></samp>.
You need to link with <samp><span class="file">libgnutls-extra</span></samp> to be able to use these
functions (see <a href="#GnuTLS_002dextra-functions">GnuTLS-extra functions</a>).
<p>The typical control flow in an TLS/IA client (that would not require
an Application Phase for resumed sessions) would be similar to the
following:
<pre class="example"> int client_avp (gnuls_session_t *session, void *ptr,
const char *last, size_t lastlen,
char **new, size_t *newlen)
{
...
}
...
int main ()
{
gnutls_ia_client_credentials_t iacred;
...
gnutls_init (&session, GNUTLS_CLIENT);
...
/* Enable TLS/IA. */
gnutls_ia_allocate_client_credentials(&iacred);
gnutls_ia_set_client_avp_function(iacred, client_avp);
gnutls_credentials_set (session, GNUTLS_CRD_IA, iacred);
...
ret = gnutls_handshake (session);
// Error handling...
...
if (gnutls_ia_handshake_p (session))
{
ret = gnutls_ia_handshake (session);
// Error handling...
...
</pre>
<p>See below for detailed descriptions of all the functions used above.
<p>The function <code>client_avp</code> would have to be implemented by your
application. The function is responsible for handling the AVP data.
See <code>gnutls_ia_set_client_avp_function</code> below for more
information on how that function should be implemented.
<p>The control flow in a typical server is similar to the above, use
<code>gnutls_ia_server_credentials_t</code> instead of
<code>gnutls_ia_client_credentials_t</code>, and replace the call to the
client functions with the corresponding server functions.
<h4 class="subheading">gnutls_ia_allocate_client_credentials</h4>
<p><a name="gnutls_005fia_005fallocate_005fclient_005fcredentials"></a>
<div class="defun">
— Function: int <b>gnutls_ia_allocate_client_credentials</b> (<var>gnutls_ia_client_credentials_t * sc</var>)<var><a name="index-gnutls_005fia_005fallocate_005fclient_005fcredentials-423"></a></var><br>
<blockquote><p><var>sc</var>: is a pointer to an <code>gnutls_ia_server_credentials_t</code> structure.
<p>This structure is complex enough to manipulate directly thus this
helper function is provided in order to allocate it.
<p>Adding this credential to a session will enable TLS/IA, and will
require an Application Phase after the TLS handshake (if the server
support TLS/IA). Use <code>gnutls_ia_require_inner_phase()</code> to toggle the
TLS/IA mode.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_ia_allocate_server_credentials</h4>
<p><a name="gnutls_005fia_005fallocate_005fserver_005fcredentials"></a>
<div class="defun">
— Function: int <b>gnutls_ia_allocate_server_credentials</b> (<var>gnutls_ia_server_credentials_t * sc</var>)<var><a name="index-gnutls_005fia_005fallocate_005fserver_005fcredentials-424"></a></var><br>
<blockquote><p><var>sc</var>: is a pointer to an <code>gnutls_ia_server_credentials_t</code> structure.
<p>This structure is complex enough to manipulate directly thus this
helper function is provided in order to allocate it.
<p>Adding this credential to a session will enable TLS/IA, and will
require an Application Phase after the TLS handshake (if the client
support TLS/IA). Use <code>gnutls_ia_require_inner_phase()</code> to toggle the
TLS/IA mode.
<p>Returns 0 on success.
</p></blockquote></div>
<h4 class="subheading">gnutls_ia_enable</h4>
<p><a name="gnutls_005fia_005fenable"></a>
<div class="defun">
— Function: void <b>gnutls_ia_enable</b> (<var>gnutls_session_t session, int allow_skip_on_resume</var>)<var><a name="index-gnutls_005fia_005fenable-425"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p><var>allow_skip_on_resume</var>: non-zero if local party allows to skip the
TLS/IA application phases for a resumed session.
<p>Specify whether we must advertise support for the TLS/IA extension
during the handshake.
<p>At the client side, we always advertise TLS/IA if gnutls_ia_enable
was called before the handshake; at the server side, we also
require that the client has advertised that it wants to run TLS/IA
before including the advertisement, as required by the protocol.
<p>Similarly, at the client side we always advertise that we allow
TLS/IA to be skipped for resumed sessions if <code>allow_skip_on_resume</code>
is non-zero; at the server side, we also require that the session
is indeed resumable and that the client has also advertised that it
allows TLS/IA to be skipped for resumed sessions.
<p>After the TLS handshake, call <code>gnutls_ia_handshake_p()</code> to find out
whether both parties agreed to do a TLS/IA handshake, before
calling <code>gnutls_ia_handshake()</code> or one of the lower level gnutls_ia_*
functions.
Specify whether we must advertise support for the TLS/IA extension
during the handshake.
<p>At the client side, we always advertise TLS/IA if gnutls_ia_enable
was called before the handshake; at the server side, we also
require that the client has advertised that it wants to run TLS/IA
before including the advertisement, as required by the protocol.
<p>Similarly, at the client side we always advertise that we allow
TLS/IA to be skipped for resumed sessions if <code>allow_skip_on_resume</code>
is non-zero; at the server side, we also require that the session
is indeed resumable and that the client has also advertised that it
allows TLS/IA to be skipped for resumed sessions.
<p>After the TLS handshake, call <code>gnutls_ia_handshake_p()</code> to find out
whether both parties agreed to do a TLS/IA handshake, before
calling <code>gnutls_ia_handshake()</code> or one of the lower level gnutls_ia_*
functions.
</p></blockquote></div>
<h4 class="subheading">gnutls_ia_endphase_send</h4>
<p><a name="gnutls_005fia_005fendphase_005fsend"></a>
<div class="defun">
— Function: int <b>gnutls_ia_endphase_send</b> (<var>gnutls_session_t session, int final_p</var>)<var><a name="index-gnutls_005fia_005fendphase_005fsend-426"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p><var>final_p</var>: Set iff this should signal the final phase.
<p>Send a TLS/IA end phase message.
<p>In the client, this should only be used to acknowledge an end phase
message sent by the server.
<p>In the server, this can be called instead of <code>gnutls_ia_send()</code> if
the server wishes to end an application phase.
<p><strong>Return value:</strong> Return 0 on success, or an error code.
</p></blockquote></div>
<h4 class="subheading">gnutls_ia_extract_inner_secret</h4>
<p><a name="gnutls_005fia_005fextract_005finner_005fsecret"></a>
<div class="defun">
— Function: void <b>gnutls_ia_extract_inner_secret</b> (<var>gnutls_session_t session, char * buffer</var>)<var><a name="index-gnutls_005fia_005fextract_005finner_005fsecret-427"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p><var>buffer</var>: pre-allocated buffer to hold 48 bytes of inner secret.
<p>Copy the 48 bytes large inner secret into the specified buffer
<p>This function is typically used after the TLS/IA handshake has
concluded. The TLS/IA inner secret can be used as input to a PRF
to derive session keys. Do not use the inner secret directly as a
session key, because for a resumed session that does not include an
application phase, the inner secret will be identical to the inner
secret in the original session. It is important to include, for
example, the client and server randomness when deriving a sesssion
key from the inner secret.
</p></blockquote></div>
<h4 class="subheading">gnutls_ia_free_client_credentials</h4>
<p><a name="gnutls_005fia_005ffree_005fclient_005fcredentials"></a>
<div class="defun">
— Function: void <b>gnutls_ia_free_client_credentials</b> (<var>gnutls_ia_client_credentials_t sc</var>)<var><a name="index-gnutls_005fia_005ffree_005fclient_005fcredentials-428"></a></var><br>
<blockquote><p><var>sc</var>: is an <code>gnutls_ia_client_credentials_t</code> structure.
<p>This structure is complex enough to manipulate directly thus this
helper function is provided in order to free (deallocate) it.
</p></blockquote></div>
<h4 class="subheading">gnutls_ia_free_server_credentials</h4>
<p><a name="gnutls_005fia_005ffree_005fserver_005fcredentials"></a>
<div class="defun">
— Function: void <b>gnutls_ia_free_server_credentials</b> (<var>gnutls_ia_server_credentials_t sc</var>)<var><a name="index-gnutls_005fia_005ffree_005fserver_005fcredentials-429"></a></var><br>
<blockquote><p><var>sc</var>: is an <code>gnutls_ia_server_credentials_t</code> structure.
<p>This structure is complex enough to manipulate directly thus this
helper function is provided in order to free (deallocate) it.
</p></blockquote></div>
<h4 class="subheading">gnutls_ia_generate_challenge</h4>
<p><a name="gnutls_005fia_005fgenerate_005fchallenge"></a>
<div class="defun">
— Function: int <b>gnutls_ia_generate_challenge</b> (<var>gnutls_session_t session, size_t buffer_size, char * buffer</var>)<var><a name="index-gnutls_005fia_005fgenerate_005fchallenge-430"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p><var>buffer_size</var>: size of output buffer.
<p><var>buffer</var>: pre-allocated buffer to contain <code>buffer_size</code> bytes of output.
<p>Generate an application challenge that the client cannot control or
predict, based on the TLS/IA inner secret.
<p><strong>Return value:</strong> Returns 0 on success, or an negative error code.
</p></blockquote></div>
<h4 class="subheading">gnutls_ia_get_client_avp_ptr</h4>
<p><a name="gnutls_005fia_005fget_005fclient_005favp_005fptr"></a>
<div class="defun">
— Function: void * <b>gnutls_ia_get_client_avp_ptr</b> (<var>gnutls_ia_client_credentials_t cred</var>)<var><a name="index-gnutls_005fia_005fget_005fclient_005favp_005fptr-431"></a></var><br>
<blockquote><p><var>cred</var>: is a <code>gnutls_ia_client_credentials_t</code> structure.
<p>Returns the pointer that will be provided to the TLS/IA callback
function as the first argument.
</p></blockquote></div>
<h4 class="subheading">gnutls_ia_get_server_avp_ptr</h4>
<p><a name="gnutls_005fia_005fget_005fserver_005favp_005fptr"></a>
<div class="defun">
— Function: void * <b>gnutls_ia_get_server_avp_ptr</b> (<var>gnutls_ia_server_credentials_t cred</var>)<var><a name="index-gnutls_005fia_005fget_005fserver_005favp_005fptr-432"></a></var><br>
<blockquote><p><var>cred</var>: is a <code>gnutls_ia_client_credentials_t</code> structure.
<p>Returns the pointer that will be provided to the TLS/IA callback
function as the first argument.
</p></blockquote></div>
<h4 class="subheading">gnutls_ia_handshake_p</h4>
<p><a name="gnutls_005fia_005fhandshake_005fp"></a>
<div class="defun">
— Function: int <b>gnutls_ia_handshake_p</b> (<var>gnutls_session_t session</var>)<var><a name="index-gnutls_005fia_005fhandshake_005fp-433"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p>Predicate to be used after <code>gnutls_handshake()</code> to decide whether to
invoke <code>gnutls_ia_handshake()</code>. Usable by both clients and servers.
<p><strong>Return value:</strong> non-zero if TLS/IA handshake is expected, zero
otherwise.
</p></blockquote></div>
<h4 class="subheading">gnutls_ia_handshake</h4>
<p><a name="gnutls_005fia_005fhandshake"></a>
<div class="defun">
— Function: int <b>gnutls_ia_handshake</b> (<var>gnutls_session_t session</var>)<var><a name="index-gnutls_005fia_005fhandshake-434"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p>Perform a TLS/IA handshake. This should be called after
<code>gnutls_handshake()</code> iff <code>gnutls_ia_handshake_p()</code>.
<p>Return 0 on success, or an error code.
</p></blockquote></div>
<h4 class="subheading">gnutls_ia_permute_inner_secret</h4>
<p><a name="gnutls_005fia_005fpermute_005finner_005fsecret"></a>
<div class="defun">
— Function: int <b>gnutls_ia_permute_inner_secret</b> (<var>gnutls_session_t session, size_t session_keys_size, const char * session_keys</var>)<var><a name="index-gnutls_005fia_005fpermute_005finner_005fsecret-435"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p><var>session_keys_size</var>: Size of generated session keys (0 if none).
<p><var>session_keys</var>: Generated session keys, used to permute inner secret
(NULL if none).
<p>Permute the inner secret using the generated session keys.
<p>This can be called in the TLS/IA AVP callback to mix any generated
session keys with the TLS/IA inner secret.
<p><strong>Return value:</strong> Return zero on success, or a negative error code.
</p></blockquote></div>
<h4 class="subheading">gnutls_ia_recv</h4>
<p><a name="gnutls_005fia_005frecv"></a>
<div class="defun">
— Function: ssize_t <b>gnutls_ia_recv</b> (<var>gnutls_session_t session, char * data, size_t sizeofdata</var>)<var><a name="index-gnutls_005fia_005frecv-436"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p><var>data</var>: the buffer that the data will be read into, must hold >= 12 bytes.
<p><var>sizeofdata</var>: the number of requested bytes, must be >= 12.
<p>Receive TLS/IA data. This function has the similar semantics with
<code>recv()</code>. The only difference is that is accepts a GNUTLS session,
and uses different error codes.
<p>If the server attempt to finish an application phase, this function
will return <code>GNUTLS_E_WARNING_IA_IPHF_RECEIVED</code> or
<code>GNUTLS_E_WARNING_IA_FPHF_RECEIVED</code>. The caller should then invoke
<code>gnutls_ia_verify_endphase()</code>, and if it runs the client side, also
send an endphase message of its own using gnutls_ia_endphase_send.
<p>If EINTR is returned by the internal push function (the default is
<code>code</code>{<code>recv()</code>}) then GNUTLS_E_INTERRUPTED will be returned. If
GNUTLS_E_INTERRUPTED or GNUTLS_E_AGAIN is returned, you must call
this function again, with the same parameters; alternatively you
could provide a NULL pointer for data, and 0 for size.
<p>Returns the number of bytes received. A negative error code is
returned in case of an error. The
<code>GNUTLS_E_WARNING_IA_IPHF_RECEIVED</code> and
<code>GNUTLS_E_WARNING_IA_FPHF_RECEIVED</code> errors are returned when an
application phase finished message has been sent by the server.
</p></blockquote></div>
<h4 class="subheading">gnutls_ia_send</h4>
<p><a name="gnutls_005fia_005fsend"></a>
<div class="defun">
— Function: ssize_t <b>gnutls_ia_send</b> (<var>gnutls_session_t session, const char * data, size_t sizeofdata</var>)<var><a name="index-gnutls_005fia_005fsend-437"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p><var>data</var>: contains the data to send
<p><var>sizeofdata</var>: is the length of the data
<p>Send TLS/IA application payload data. This function has the
similar semantics with <code>send()</code>. The only difference is that is
accepts a GNUTLS session, and uses different error codes.
<p>The TLS/IA protocol is synchronous, so you cannot send more than
one packet at a time. The client always send the first packet.
<p>To finish an application phase in the server, use
<code>gnutls_ia_endphase_send()</code>. The client cannot end an application
phase unilaterally; rather, a client is required to respond with an
endphase of its own if gnutls_ia_recv indicates that the server has
sent one.
<p>If the EINTR is returned by the internal push function (the default
is <code>send()</code>} then <code>GNUTLS_E_INTERRUPTED</code> will be returned. If
<code>GNUTLS_E_INTERRUPTED</code> or <code>GNUTLS_E_AGAIN</code> is returned, you must call
this function again, with the same parameters; alternatively you
could provide a <code>NULL</code> pointer for data, and 0 for size.
<p>Returns the number of bytes sent, or a negative error code.
</p></blockquote></div>
<h4 class="subheading">gnutls_ia_set_client_avp_function</h4>
<p><a name="gnutls_005fia_005fset_005fclient_005favp_005ffunction"></a>
<div class="defun">
— Function: void <b>gnutls_ia_set_client_avp_function</b> (<var>gnutls_ia_client_credentials_t cred, gnutls_ia_avp_func avp_func</var>)<var><a name="index-gnutls_005fia_005fset_005fclient_005favp_005ffunction-438"></a></var><br>
<blockquote><p><var>cred</var>: is a <code>gnutls_ia_client_credentials_t</code> structure.
<p><var>avp_func</var>: is the callback function
<p>Set the TLS/IA AVP callback handler used for the session.
<p>The AVP callback is called to process AVPs received from the
server, and to get a new AVP to send to the server.
<p>The callback's function form is:
int (*avp_func) (gnutls_session_t session, void *ptr,
const char *last, size_t lastlen,
char **next, size_t *nextlen);
<p>The <code>session</code> parameter is the <code>gnutls_session_t</code> structure
corresponding to the current session. The <code>ptr</code> parameter is the
application hook pointer, set through
<code>gnutls_ia_set_client_avp_ptr()</code>. The AVP received from the server
is present in <code>last</code> of <code>lastlen</code> size, which will be <code>NULL</code> on the
first invocation. The newly allocated output AVP to send to the
server should be placed in *<code>next</code> of *<code>nextlen</code> size.
<p>The callback may invoke <code>gnutls_ia_permute_inner_secret()</code> to mix any
generated session keys with the TLS/IA inner secret.
<p>Return 0 (<code>GNUTLS_IA_APPLICATION_PAYLOAD</code>) on success, or a negative
error code to abort the TLS/IA handshake.
<p>Note that the callback must use allocate the <code>next</code> parameter using
<code>gnutls_malloc()</code>, because it is released via <code>gnutls_free()</code> by the
TLS/IA handshake function.
</p></blockquote></div>
<h4 class="subheading">gnutls_ia_set_client_avp_ptr</h4>
<p><a name="gnutls_005fia_005fset_005fclient_005favp_005fptr"></a>
<div class="defun">
— Function: void <b>gnutls_ia_set_client_avp_ptr</b> (<var>gnutls_ia_client_credentials_t cred, void * ptr</var>)<var><a name="index-gnutls_005fia_005fset_005fclient_005favp_005fptr-439"></a></var><br>
<blockquote><p><var>cred</var>: is a <code>gnutls_ia_client_credentials_t</code> structure.
<p><var>ptr</var>: is the pointer
<p>Sets the pointer that will be provided to the TLS/IA callback
function as the first argument.
</p></blockquote></div>
<h4 class="subheading">gnutls_ia_set_server_avp_function</h4>
<p><a name="gnutls_005fia_005fset_005fserver_005favp_005ffunction"></a>
<div class="defun">
— Function: void <b>gnutls_ia_set_server_avp_function</b> (<var>gnutls_ia_server_credentials_t cred, gnutls_ia_avp_func avp_func</var>)<var><a name="index-gnutls_005fia_005fset_005fserver_005favp_005ffunction-440"></a></var><br>
<blockquote><p><var>cred</var>: is a <code>gnutls_ia_server_credentials_t</code> structure.
<p>Set the TLS/IA AVP callback handler used for the session.
<p>The callback's function form is:
int (*avp_func) (gnutls_session_t session, void *ptr,
const char *last, size_t lastlen,
char **next, size_t *nextlen);
<p>The <code>session</code> parameter is the <code>gnutls_session_t</code> structure
corresponding to the current session. The <code>ptr</code> parameter is the
application hook pointer, set through
<code>gnutls_ia_set_server_avp_ptr()</code>. The AVP received from the client
is present in <code>last</code> of <code>lastlen</code> size. The newly allocated output
AVP to send to the client should be placed in *<code>next</code> of *<code>nextlen</code>
size.
<p>The AVP callback is called to process incoming AVPs from the
client, and to get a new AVP to send to the client. It can also be
used to instruct the TLS/IA handshake to do go into the
Intermediate or Final phases. It return a negative error code, or
an <code>gnutls_ia_apptype_t</code> message type.
<p>The callback may invoke <code>gnutls_ia_permute_inner_secret()</code> to mix any
generated session keys with the TLS/IA inner secret.
<p>Specifically, return <code>GNUTLS_IA_APPLICATION_PAYLOAD</code> (0) to send
another AVP to the client, return
<code>GNUTLS_IA_INTERMEDIATE_PHASE_FINISHED</code> (1) to indicate that an
IntermediatePhaseFinished message should be sent, and return
<code>GNUTLS_IA_FINAL_PHASE_FINISHED</code> (2) to indicate that an
FinalPhaseFinished message should be sent. In the last two cases,
the contents of the <code>next</code> and <code>nextlen</code> parameter is not used.
<p>Note that the callback must use allocate the <code>next</code> parameter using
<code>gnutls_malloc()</code>, because it is released via <code>gnutls_free()</code> by the
TLS/IA handshake function.
</p></blockquote></div>
<h4 class="subheading">gnutls_ia_set_server_avp_ptr</h4>
<p><a name="gnutls_005fia_005fset_005fserver_005favp_005fptr"></a>
<div class="defun">
— Function: void <b>gnutls_ia_set_server_avp_ptr</b> (<var>gnutls_ia_server_credentials_t cred, void * ptr</var>)<var><a name="index-gnutls_005fia_005fset_005fserver_005favp_005fptr-441"></a></var><br>
<blockquote><p><var>cred</var>: is a <code>gnutls_ia_client_credentials_t</code> structure.
<p><var>ptr</var>: is the pointer
<p>Sets the pointer that will be provided to the TLS/IA callback
function as the first argument.
</p></blockquote></div>
<h4 class="subheading">gnutls_ia_verify_endphase</h4>
<p><a name="gnutls_005fia_005fverify_005fendphase"></a>
<div class="defun">
— Function: int <b>gnutls_ia_verify_endphase</b> (<var>gnutls_session_t session, const char * checksum</var>)<var><a name="index-gnutls_005fia_005fverify_005fendphase-442"></a></var><br>
<blockquote><p><var>session</var>: is a <code>gnutls_session_t</code> structure.
<p><var>checksum</var>: 12-byte checksum data, received from <code>gnutls_ia_recv()</code>.
<p>Verify TLS/IA end phase checksum data. If verification fails, the
<code>GNUTLS_A_INNER_APPLICATION_VERIFICATION</code> alert is sent to the other
sie.
<p>This function is called when <code>gnutls_ia_recv()</code> return
<code>GNUTLS_E_WARNING_IA_IPHF_RECEIVED</code> or
<code>GNUTLS_E_WARNING_IA_FPHF_RECEIVED</code>.
<p><strong>Return value:</strong> Return 0 on successful verification, or an error
code. If the checksum verification of the end phase message fails,
<code>GNUTLS_E_IA_VERIFY_FAILED</code> is returned.
</p></blockquote></div>
<div class="node">
<p><hr>
<a name="Error-codes-and-descriptions"></a>
Previous: <a rel="previous" accesskey="p" href="#TLS-Inner-Application-_0028TLS_002fIA_0029-functions">TLS Inner Application (TLS/IA) functions</a>,
Up: <a rel="up" accesskey="u" href="#Function-reference">Function reference</a>
</div>
<h3 class="section">9.6 Error codes and descriptions</h3>
<p><a name="Error-Codes"></a>
<a name="index-Error-codes-443"></a>
The error codes used throughout the library are described below. The
return code <code>GNUTLS_E_SUCCESS</code> indicate successful operation, and
is guaranteed to have the value 0, so you can use it in logical
expressions.
<dl>
<dt><code>GNUTLS_E_AGAIN:</code><dd>Function was interrupted.
<br><dt><code>GNUTLS_E_ASN1_DER_ERROR:</code><dd>ASN1 parser: Error in DER parsing.
<br><dt><code>GNUTLS_E_ASN1_DER_OVERFLOW:</code><dd>ASN1 parser: Overflow in DER parsing.
<br><dt><code>GNUTLS_E_ASN1_ELEMENT_NOT_FOUND:</code><dd>ASN1 parser: Element was not found.
<br><dt><code>GNUTLS_E_ASN1_GENERIC_ERROR:</code><dd>ASN1 parser: Generic parsing error.
<br><dt><code>GNUTLS_E_ASN1_IDENTIFIER_NOT_FOUND:</code><dd>ASN1 parser: Identifier was not found
<br><dt><code>GNUTLS_E_ASN1_SYNTAX_ERROR:</code><dd>ASN1 parser: Syntax error.
<br><dt><code>GNUTLS_E_ASN1_TAG_ERROR:</code><dd>ASN1 parser: Error in TAG.
<br><dt><code>GNUTLS_E_ASN1_TAG_IMPLICIT:</code><dd>ASN1 parser: error in implicit tag
<br><dt><code>GNUTLS_E_ASN1_TYPE_ANY_ERROR:</code><dd>ASN1 parser: Error in type 'ANY'.
<br><dt><code>GNUTLS_E_ASN1_VALUE_NOT_FOUND:</code><dd>ASN1 parser: Value was not found.
<br><dt><code>GNUTLS_E_ASN1_VALUE_NOT_VALID:</code><dd>ASN1 parser: Value is not valid.
<br><dt><code>GNUTLS_E_BASE64_DECODING_ERROR:</code><dd>Base64 decoding error.
<br><dt><code>GNUTLS_E_BASE64_ENCODING_ERROR:</code><dd>Base64 encoding error.
<br><dt><code>GNUTLS_E_CERTIFICATE_ERROR:</code><dd>Error in the certificate.
<br><dt><code>GNUTLS_E_CERTIFICATE_KEY_MISMATCH:</code><dd>The certificate and the given key do not match.
<br><dt><code>GNUTLS_E_COMPRESSION_FAILED:</code><dd>Compression of the TLS record packet has failed.
<br><dt><code>GNUTLS_E_CONSTRAINT_ERROR:</code><dd>Some constraint limits were reached.
<br><dt><code>GNUTLS_E_DB_ERROR:</code><dd>Error in Database backend.
<br><dt><code>GNUTLS_E_DECOMPRESSION_FAILED:</code><dd>Decompression of the TLS record packet has failed.
<br><dt><code>GNUTLS_E_DECRYPTION_FAILED:</code><dd>Decryption has failed.
<br><dt><code>GNUTLS_E_DH_PRIME_UNACCEPTABLE:</code><dd>The Diffie Hellman prime sent by the server is not acceptable (not long enough).
<br><dt><code>GNUTLS_E_ENCRYPTION_FAILED:</code><dd>Encryption has failed.
<br><dt><code>GNUTLS_E_ERROR_IN_FINISHED_PACKET:</code><dd>An error was encountered at the TLS Finished packet calculation.
<br><dt><code>GNUTLS_E_EXPIRED:</code><dd>The requested session has expired.
<br><dt><code>GNUTLS_E_FATAL_ALERT_RECEIVED:</code><dd>A TLS fatal alert has been received.
<br><dt><code>GNUTLS_E_FILE_ERROR:</code><dd>Error while reading file.
<br><dt><code>GNUTLS_E_GOT_APPLICATION_DATA:</code><dd>TLS Application data were received, while expecting handshake data.
<br><dt><code>GNUTLS_E_HASH_FAILED:</code><dd>Hashing has failed.
<br><dt><code>GNUTLS_E_IA_VERIFY_FAILED:</code><dd>Verifying TLS/IA phase checksum failed
<br><dt><code>GNUTLS_E_ILLEGAL_SRP_USERNAME:</code><dd>The SRP username supplied is illegal.
<br><dt><code>GNUTLS_E_INCOMPATIBLE_GCRYPT_LIBRARY:</code><dd>The gcrypt library version is too old.
<br><dt><code>GNUTLS_E_INCOMPATIBLE_LIBTASN1_LIBRARY:</code><dd>The tasn1 library version is too old.
<br><dt><code>GNUTLS_E_INIT_LIBEXTRA:</code><dd>The initialization of GnuTLS-extra has failed.
<br><dt><code>GNUTLS_E_INSUFFICIENT_CREDENTIALS:</code><dd>Insufficient credentials for that request.
<br><dt><code>GNUTLS_E_INTERNAL_ERROR:</code><dd>GnuTLS internal error.
<br><dt><code>GNUTLS_E_INTERRUPTED:</code><dd>Function was interrupted.
<br><dt><code>GNUTLS_E_INVALID_PASSWORD:</code><dd>The given password contains invalid characters.
<br><dt><code>GNUTLS_E_INVALID_REQUEST:</code><dd>The request is invalid.
<br><dt><code>GNUTLS_E_INVALID_SESSION:</code><dd>The specified session has been invalidated for some reason.
<br><dt><code>GNUTLS_E_KEY_USAGE_VIOLATION:</code><dd>Key usage violation in certificate has been detected.
<br><dt><code>GNUTLS_E_LARGE_PACKET:</code><dd>A large TLS record packet was received.
<br><dt><code>GNUTLS_E_LIBRARY_VERSION_MISMATCH:</code><dd>The GnuTLS library version does not match the GnuTLS-extra library version.
<br><dt><code>GNUTLS_E_LZO_INIT_FAILED:</code><dd>The initialization of LZO has failed.
<br><dt><code>GNUTLS_E_MAC_VERIFY_FAILED:</code><dd>The Message Authentication Code verification failed.
<br><dt><code>GNUTLS_E_MEMORY_ERROR:</code><dd>Internal error in memory allocation.
<br><dt><code>GNUTLS_E_MPI_PRINT_FAILED:</code><dd>Could not export a large integer.
<br><dt><code>GNUTLS_E_MPI_SCAN_FAILED:</code><dd>The scanning of a large integer has failed.
<br><dt><code>GNUTLS_E_NO_CERTIFICATE_FOUND:</code><dd>The peer did not send any certificate.
<br><dt><code>GNUTLS_E_NO_CIPHER_SUITES:</code><dd>No supported cipher suites have been found.
<br><dt><code>GNUTLS_E_NO_COMPRESSION_ALGORITHMS:</code><dd>No supported compression algorithms have been found.
<br><dt><code>GNUTLS_E_NO_TEMPORARY_DH_PARAMS:</code><dd>No temporary DH parameters were found.
<br><dt><code>GNUTLS_E_NO_TEMPORARY_RSA_PARAMS:</code><dd>No temporary RSA parameters were found.
<br><dt><code>GNUTLS_E_OPENPGP_FINGERPRINT_UNSUPPORTED:</code><dd>The OpenPGP fingerprint is not supported.
<br><dt><code>GNUTLS_E_OPENPGP_GETKEY_FAILED:</code><dd>Could not get OpenPGP key.
<br><dt><code>GNUTLS_E_OPENPGP_KEYRING_ERROR:</code><dd>Error loading the keyring.
<br><dt><code>GNUTLS_E_OPENPGP_TRUSTDB_VERSION_UNSUPPORTED:</code><dd>The specified GnuPG TrustDB version is not supported. TrustDB v4 is supported.
<br><dt><code>GNUTLS_E_PKCS1_WRONG_PAD:</code><dd>Wrong padding in PKCS1 packet.
<br><dt><code>GNUTLS_E_PK_DECRYPTION_FAILED:</code><dd>Public key decryption has failed.
<br><dt><code>GNUTLS_E_PK_ENCRYPTION_FAILED:</code><dd>Public key encryption has failed.
<br><dt><code>GNUTLS_E_PK_SIGN_FAILED:</code><dd>Public key signing has failed.
<br><dt><code>GNUTLS_E_PK_SIG_VERIFY_FAILED:</code><dd>Public key signature verification has failed.
<br><dt><code>GNUTLS_E_PULL_ERROR:</code><dd>Error in the pull function.
<br><dt><code>GNUTLS_E_PUSH_ERROR:</code><dd>Error in the push function.
<br><dt><code>GNUTLS_E_RANDOM_FAILED:</code><dd>Failed to acquire random data.
<br><dt><code>GNUTLS_E_RECEIVED_ILLEGAL_EXTENSION:</code><dd>An illegal TLS extension was received.
<br><dt><code>GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER:</code><dd>An illegal parameter has been received.
<br><dt><code>GNUTLS_E_RECORD_LIMIT_REACHED:</code><dd>The upper limit of record packet sequence numbers has been reached. Wow!
<br><dt><code>GNUTLS_E_REHANDSHAKE:</code><dd>Rehandshake was requested by the peer.
<br><dt><code>GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE:</code><dd>The requested data were not available.
<br><dt><code>GNUTLS_E_SHORT_MEMORY_BUFFER:</code><dd>The given memory buffer is too short to hold parameters.
<br><dt><code>GNUTLS_E_SRP_PWD_ERROR:</code><dd>Error in password file.
<br><dt><code>GNUTLS_E_SRP_PWD_PARSING_ERROR:</code><dd>Parsing error in password file.
<br><dt><code>GNUTLS_E_SUCCESS:</code><dd>Success.
<br><dt><code>GNUTLS_E_TOO_MANY_EMPTY_PACKETS:</code><dd>Too many empty record packets have been received.
<br><dt><code>GNUTLS_E_UNEXPECTED_HANDSHAKE_PACKET:</code><dd>An unexpected TLS handshake packet was received.
<br><dt><code>GNUTLS_E_UNEXPECTED_PACKET:</code><dd>An unexpected TLS packet was received.
<br><dt><code>GNUTLS_E_UNEXPECTED_PACKET_LENGTH:</code><dd>A TLS packet with unexpected length was received.
<br><dt><code>GNUTLS_E_UNKNOWN_CIPHER_SUITE:</code><dd>Could not negotiate a supported cipher suite.
<br><dt><code>GNUTLS_E_UNKNOWN_CIPHER_TYPE:</code><dd>The cipher type is unsupported.
<br><dt><code>GNUTLS_E_UNKNOWN_COMPRESSION_ALGORITHM:</code><dd>Could not negotiate a supported compression method.
<br><dt><code>GNUTLS_E_UNKNOWN_HASH_ALGORITHM:</code><dd>The hash algorithm is unknown.
<br><dt><code>GNUTLS_E_UNKNOWN_PKCS_BAG_TYPE:</code><dd>The PKCS structure's bag type is unknown.
<br><dt><code>GNUTLS_E_UNKNOWN_PKCS_CONTENT_TYPE:</code><dd>The PKCS structure's content type is unknown.
<br><dt><code>GNUTLS_E_UNKNOWN_PK_ALGORITHM:</code><dd>An unknown public key algorithm was encountered.
<br><dt><code>GNUTLS_E_UNSUPPORTED_CERTIFICATE_TYPE:</code><dd>The certificate type is not supported.
<br><dt><code>GNUTLS_E_UNSUPPORTED_VERSION_PACKET:</code><dd>A record packet with illegal version was received.
<br><dt><code>GNUTLS_E_UNWANTED_ALGORITHM:</code><dd>An algorithm that is not enabled was negotiated.
<br><dt><code>GNUTLS_E_WARNING_ALERT_RECEIVED:</code><dd>A TLS warning alert has been received.
<br><dt><code>GNUTLS_E_WARNING_IA_FPHF_RECEIVED:</code><dd>Received a TLS/IA Final Phase Finished message
<br><dt><code>GNUTLS_E_WARNING_IA_IPHF_RECEIVED:</code><dd>Received a TLS/IA Intermediate Phase Finished message
<br><dt><code>GNUTLS_E_X509_UNKNOWN_SAN:</code><dd>Unknown Subject Alternative name in X.509 certificate.
<br><dt><code>GNUTLS_E_X509_UNSUPPORTED_ATTRIBUTE:</code><dd>The certificate has unsupported attributes.
<br><dt><code>GNUTLS_E_X509_UNSUPPORTED_CRITICAL_EXTENSION:</code><dd>Unsupported critical extension in X.509 certificate.
<br><dt><code>GNUTLS_E_X509_UNSUPPORTED_OID:</code><dd>The OID is not supported.
</dl>
<div class="node">
<p><hr>
<a name="Certificate-to-XML-convertion-functions"></a>
Next: <a rel="next" accesskey="n" href="#All-the-supported-ciphersuites-in-GnuTLS">All the supported ciphersuites in GnuTLS</a>,
Previous: <a rel="previous" accesskey="p" href="#Function-reference">Function reference</a>,
Up: <a rel="up" accesskey="u" href="#Top">Top</a>
</div>
<h2 class="chapter">10 Certificate to <acronym>XML</acronym> convertion functions</h2>
<p><a name="index-Certificate-to-XML-convertion-444"></a>
This appendix contains some example output of the XML convertion
functions:
<ul>
<li><a href="#gnutls_005fx509_005fcrt_005fto_005fxml">gnutls_x509_crt_to_xml</a>
<li><a href="#gnutls_005fopenpgp_005fkey_005fto_005fxml">gnutls_openpgp_key_to_xml</a>
</ul>
<ul class="menu">
<li><a accesskey="1" href="#An-X_002e509-certificate">An X.509 certificate</a>
<li><a accesskey="2" href="#An-OpenPGP-key">An OpenPGP key</a>
</ul>
<div class="node">
<p><hr>
<a name="An-X.509-certificate"></a>
<a name="An-X_002e509-certificate"></a>
Next: <a rel="next" accesskey="n" href="#An-OpenPGP-key">An OpenPGP key</a>,
Up: <a rel="up" accesskey="u" href="#Certificate-to-XML-convertion-functions">Certificate to XML convertion functions</a>
</div>
<h3 class="section">10.1 An <acronym>X.509</acronym> certificate</h3>
<pre class="smallexample"> <?xml version="1.0" encoding="UTF-8"?>
<gnutls:x509:certificate version="1.1">
<certificate type="SEQUENCE">
<tbsCertificate type="SEQUENCE">
<version type="INTEGER" encoding="HEX">02</version>
<serialNumber type="INTEGER" encoding="HEX">01</serialNumber>
<signature type="SEQUENCE">
<algorithm type="OBJECT ID">1.2.840.113549.1.1.4</algorithm>
<parameters type="ANY">
<md5WithRSAEncryption encoding="HEX">0500</md5WithRSAEncryption>
</parameters>
</signature>
<issuer type="CHOICE">
<rdnSequence type="SEQUENCE OF">
<unnamed1 type="SET OF">
<unnamed1 type="SEQUENCE">
<type type="OBJECT ID">2.5.4.6</type>
<value type="ANY">
<X520countryName>GR</X520countryName>
</value>
</unnamed1>
</unnamed1>
<unnamed2 type="SET OF">
<unnamed1 type="SEQUENCE">
<type type="OBJECT ID">2.5.4.8</type>
<value type="ANY">
<X520StateOrProvinceName>Attiki</X520StateOrProvinceName>
</value>
</unnamed1>
</unnamed2>
<unnamed3 type="SET OF">
<unnamed1 type="SEQUENCE">
<type type="OBJECT ID">2.5.4.7</type>
<value type="ANY">
<X520LocalityName>Athina</X520LocalityName>
</value>
</unnamed1>
</unnamed3>
<unnamed4 type="SET OF">
<unnamed1 type="SEQUENCE">
<type type="OBJECT ID">2.5.4.10</type>
<value type="ANY">
<X520OrganizationName>GNUTLS</X520OrganizationName>
</value>
</unnamed1>
</unnamed4>
<unnamed5 type="SET OF">
<unnamed1 type="SEQUENCE">
<type type="OBJECT ID">2.5.4.11</type>
<value type="ANY">
<X520OrganizationalUnitName>GNUTLS dev.</X520OrganizationalUnitName>
</value>
</unnamed1>
</unnamed5>
<unnamed6 type="SET OF">
<unnamed1 type="SEQUENCE">
<type type="OBJECT ID">2.5.4.3</type>
<value type="ANY">
<X520CommonName>GNUTLS TEST CA</X520CommonName>
</value>
</unnamed1>
</unnamed6>
<unnamed7 type="SET OF">
<unnamed1 type="SEQUENCE">
<type type="OBJECT ID">1.2.840.113549.1.9.1</type>
<value type="ANY">
<Pkcs9email>gnutls-dev@gnupg.org</Pkcs9email>
</value>
</unnamed1>
</unnamed7>
</rdnSequence>
</issuer>
<validity type="SEQUENCE">
<notBefore type="CHOICE">
<utcTime type="TIME">010707101845Z</utcTime>
</notBefore>
<notAfter type="CHOICE">
<utcTime type="TIME">020707101845Z</utcTime>
</notAfter>
</validity>
<subject type="CHOICE">
<rdnSequence type="SEQUENCE OF">
<unnamed1 type="SET OF">
<unnamed1 type="SEQUENCE">
<type type="OBJECT ID">2.5.4.6</type>
<value type="ANY">
<X520countryName>GR</X520countryName>
</value>
</unnamed1>
</unnamed1>
<unnamed2 type="SET OF">
<unnamed1 type="SEQUENCE">
<type type="OBJECT ID">2.5.4.8</type>
<value type="ANY">
<X520StateOrProvinceName>Attiki</X520StateOrProvinceName>
</value>
</unnamed1>
</unnamed2>
<unnamed3 type="SET OF">
<unnamed1 type="SEQUENCE">
<type type="OBJECT ID">2.5.4.7</type>
<value type="ANY">
<X520LocalityName>Athina</X520LocalityName>
</value>
</unnamed1>
</unnamed3>
<unnamed4 type="SET OF">
<unnamed1 type="SEQUENCE">
<type type="OBJECT ID">2.5.4.10</type>
<value type="ANY">
<X520OrganizationName>GNUTLS</X520OrganizationName>
</value>
</unnamed1>
</unnamed4>
<unnamed5 type="SET OF">
<unnamed1 type="SEQUENCE">
<type type="OBJECT ID">2.5.4.11</type>
<value type="ANY">
<X520OrganizationalUnitName>GNUTLS dev.</X520OrganizationalUnitName>
</value>
</unnamed1>
</unnamed5>
<unnamed6 type="SET OF">
<unnamed1 type="SEQUENCE">
<type type="OBJECT ID">2.5.4.3</type>
<value type="ANY">
<X520CommonName>localhost</X520CommonName>
</value>
</unnamed1>
</unnamed6>
<unnamed7 type="SET OF">
<unnamed1 type="SEQUENCE">
<type type="OBJECT ID">1.2.840.113549.1.9.1</type>
<value type="ANY">
<Pkcs9email>root@localhost</Pkcs9email>
</value>
</unnamed1>
</unnamed7>
</rdnSequence>
</subject>
<subjectPublicKeyInfo type="SEQUENCE">
<algorithm type="SEQUENCE">
<algorithm type="OBJECT ID">1.2.840.113549.1.1.1</algorithm>
<parameters type="ANY">
<rsaEncryption encoding="HEX">0500</rsaEncryption>
</parameters>
</algorithm>
<subjectPublicKey type="BIT STRING" encoding="HEX" length="1120">
30818902818100D00B49EBB226D951F5CC57072199DDF287683D2DA1A0E
FCC96BFF73164777C78C3991E92EDA66584E7B97BAB4BE68D595D225557
E01E7E57B5C35C04B491948C5C427AD588D8C6989764996D6D44E17B65C
CFC86F3B4842DE559B730C1DE3AEF1CE1A328AFF8A357EBA911E1F7E8FC
1598E21E4BF721748C587F50CF46157D950203010001</subjectPublicKey>
</subjectPublicKeyInfo>
<extensions type="SEQUENCE OF">
<unnamed1 type="SEQUENCE">
<extnID type="OBJECT ID">2.5.29.35</extnID>
<critical type="BOOLEAN">FALSE</critical>
<extnValue type="SEQUENCE">
<keyIdentifier type="OCTET STRING" encoding="HEX">
EFEE94ABC8CA577F5313DB76DC1A950093BAF3C9</keyIdentifier>
</extnValue>
</unnamed1>
<unnamed2 type="SEQUENCE">
<extnID type="OBJECT ID">2.5.29.37</extnID>
<critical type="BOOLEAN">FALSE</critical>
<extnValue type="SEQUENCE OF">
<unnamed1 type="OBJECT ID">1.3.6.1.5.5.7.3.1</unnamed1>
<unnamed2 type="OBJECT ID">1.3.6.1.5.5.7.3.2</unnamed2>
<unnamed3 type="OBJECT ID">1.3.6.1.4.1.311.10.3.3</unnamed3>
<unnamed4 type="OBJECT ID">2.16.840.1.113730.4.1</unnamed4>
</extnValue>
</unnamed2>
<unnamed3 type="SEQUENCE">
<extnID type="OBJECT ID">2.5.29.19</extnID>
<critical type="BOOLEAN">TRUE</critical>
<extnValue type="SEQUENCE">
<cA type="BOOLEAN">FALSE</cA>
</extnValue>
</unnamed3>
</extensions>
</tbsCertificate>
<signatureAlgorithm type="SEQUENCE">
<algorithm type="OBJECT ID">1.2.840.113549.1.1.4</algorithm>
<parameters type="ANY">
<md5WithRSAEncryption encoding="HEX">0500</md5WithRSAEncryption>
</parameters>
</signatureAlgorithm>
<signature type="BIT STRING" encoding="HEX" length="1024">
B73945273AF2A395EC54BF5DC669D953885A9D811A3B92909D24792D36A44EC
27E1C463AF8738BEFD29B311CCE8C6D9661BEC30911DAABB39B8813382B32D2
E259581EBCD26C495C083984763966FF35D1DEFE432891E610C85072578DA74
23244A8F5997B41A1F44E61F4F22C94375775055A5E72F25D5E4557467A91BD
4251</signature>
</certificate>
</gnutls:x509:certificate>
</pre>
<div class="node">
<p><hr>
<a name="An-OpenPGP-key"></a>
Previous: <a rel="previous" accesskey="p" href="#An-X_002e509-certificate">An X.509 certificate</a>,
Up: <a rel="up" accesskey="u" href="#Certificate-to-XML-convertion-functions">Certificate to XML convertion functions</a>
</div>
<h3 class="section">10.2 An <acronym>OpenPGP</acronym> key</h3>
<pre class="smallexample"> <?xml version="1.0"?>
<gnutls:openpgp:key version="1.0">
<OPENPGPKEY>
<MAINKEY>
<KEYID>BD572CDCCCC07C3</KEYID>
<FINGERPRINT>BE615E88D6CFF27225B8A2E7BD572CDCCCC07C35</FINGERPRINT>
<PKALGO>DSA</PKALGO>
<KEYLEN>1024</KEYLEN>
<CREATED>1011533164</CREATED>
<REVOKED>0</REVOKED>
<KEY ENCODING="HEX"/>
<DSA-P>0400E72E76B62EEFA9A3BD594093292418050C02D7029D6CA2066E
FC34C86038627C643EB1A652A7AF1D37CF46FC505AC1E0C699B37895B4BCB
3E53541FFDA4766D6168C2B8AAFD6AB22466D06D18034D5DAC698E6993BA5
B350FF822E1CD8702A75114E8B73A6B09CB3B93CE44DBB516C9BB5F95BB66
6188602A0A1447236C0658F</DSA-P>
<DSA-Q>00A08F5B5E78D85F792CC2072F9474645726FB4D9373</DSA-Q>
<DSA-G>03FE3578D689D6606E9118E9F9A7042B963CF23F3D8F1377A273C0
F0974DBF44B3CABCBE14DD64412555863E39A9C627662D77AC36662AE4497
92C3262D3F12E9832A7565309D67BA0AE4DF25F5EDA0937056AD5BE89F406
9EBD7EC76CE432441DF5D52FFFD06D39E5F61E36947B698A77CB62AB81E4A
4122BF9050671D9946C865E</DSA-G>
<DSA-Y>0400D061437A964DDE318818C2B24DE008E60096B60DB8A684B85A
838D119FC930311889AD57A3B927F448F84EB253C623EDA73B42FF78BCE63
A6A531D75A64CE8540513808E9F5B10CE075D3417B801164918B131D3544C
8765A8ECB9971F61A09FC73D509806106B5977D211CB0E1D04D0ED96BCE89
BAE8F73D800B052139CBF8D</DSA-Y>
</MAINKEY>
<USERID>
<NAME>OpenCDK test key (Only intended for test purposes!)</NAME>
<EMAIL>opencdk@foo-bar.org</EMAIL>
<PRIMARY>0</PRIMARY>
<REVOKED>0</REVOKED>
</USERID>
<SIGNATURE>
<VERSION>4</VERSION>
<SIGCLASS>19</SIGCLASS>
<EXPIRED>0</EXPIRED>
<PKALGO>DSA</PKALGO>
<MDALGO>SHA1</MDALGO>
<CREATED>1011533164</CREATED>
<KEYID>BD572CDCCCC07C3</KEYID>
</SIGNATURE>
<SUBKEY>
<KEYID>FCB0CF3A5261E06</KEYID>
<FINGERPRINT>297B48ACC09C0FF683CA1ED1FCB0CF3A5261E067</FINGERPRINT>
<PKALGO>ELG</PKALGO>
<KEYLEN>1024</KEYLEN>
<CREATED>1011533167</CREATED>
<REVOKED>0</REVOKED>
<KEY ENCODING="HEX"/>
<ELG-P>0400E20156526069D067D24F4D71E6D38658E08BE3BF246C1ADCE0
8DB69CD8D459C1ED335738410798755AFDB79F1797CF022E70C7960F12CA6
896D27CFD24A11CD316DDE1FBCC1EA615C5C31FEC656E467078C875FC509B
1ECB99C8B56C2D875C50E2018B5B0FA378606EB6425A2533830F55FD21D64
9015615D49A1D09E9510F5F</ELG-P>
<ELG-G>000305</ELG-G>
<ELG-Y>0400D0BDADE40432758675C87D0730C360981467BAE1BEB6CC105A
3C1F366BFDBEA12E378456513238B8AD414E52A2A9661D1DF1DB6BB5F33F6
906166107556C813224330B30932DB7C8CC8225672D7AE24AF2469750E539
B661EA6475D2E03CD8D3838DC4A8AC4AFD213536FE3E96EC9D0AEA65164B5
76E01B37A8DCA89F2B257D0</ELG-Y>
</SUBKEY>
<SIGNATURE>
<VERSION>4</VERSION>
<SIGCLASS>24</SIGCLASS>
<EXPIRED>0</EXPIRED>
<PKALGO>DSA</PKALGO>
<MDALGO>SHA1</MDALGO>
<CREATED>1011533167</CREATED>
<KEYID>BD572CDCCCC07C3</KEYID>
</SIGNATURE>
</OPENPGPKEY>
</gnutls:openpgp:key>
</pre>
<div class="node">
<p><hr>
<a name="All-the-supported-ciphersuites-in-GnuTLS"></a>
Next: <a rel="next" accesskey="n" href="#Internal-architecture-of-GnuTLS">Internal architecture of GnuTLS</a>,
Previous: <a rel="previous" accesskey="p" href="#Certificate-to-XML-convertion-functions">Certificate to XML convertion functions</a>,
Up: <a rel="up" accesskey="u" href="#Top">Top</a>
</div>
<h2 class="chapter">11 All the supported ciphersuites in <acronym>GnuTLS</acronym></h2>
<p><a name="ciphersuites"></a>
<a name="index-Ciphersuites-445"></a>
<p><table summary="">
<tr align="left"><td valign="top" width="45%"><code>TLS_RSA_NULL_MD5</code>
</td><td valign="top" width="20%">0x00 0x01
</td><td valign="top" width="35%">RFC 2246
<p><br></td></tr><tr align="left"><td valign="top" width="45%"><code>TLS_ANON_DH_3DES_EDE_CBC_SHA</code>
</td><td valign="top" width="20%">0x00 0x1B
</td><td valign="top" width="35%">RFC 2246
<p><br></td></tr><tr align="left"><td valign="top" width="45%"><code>TLS_ANON_DH_ARCFOUR_MD5</code>
</td><td valign="top" width="20%">0x00 0x18
</td><td valign="top" width="35%">RFC 2246
<p><br></td></tr><tr align="left"><td valign="top" width="45%"><code>TLS_ANON_DH_AES_128_CBC_SHA</code>
</td><td valign="top" width="20%">0x00 0x34
</td><td valign="top" width="35%">RFC 2246
<p><br></td></tr><tr align="left"><td valign="top" width="45%"><code>TLS_ANON_DH_AES_256_CBC_SHA</code>
</td><td valign="top" width="20%">0x00 0x3A
</td><td valign="top" width="35%">RFC 2246
<p><br></td></tr><tr align="left"><td valign="top" width="45%"><code>TLS_RSA_ARCFOUR_SHA</code>
</td><td valign="top" width="20%">0x00 0x05
</td><td valign="top" width="35%">RFC 2246
<p><br></td></tr><tr align="left"><td valign="top" width="45%"><code>TLS_RSA_ARCFOUR_MD5</code>
</td><td valign="top" width="20%">0x00 0x04
</td><td valign="top" width="35%">RFC 2246
<p><br></td></tr><tr align="left"><td valign="top" width="45%"><code>TLS_RSA_3DES_EDE_CBC_SHA</code>
</td><td valign="top" width="20%">0x00 0x0A
</td><td valign="top" width="35%">RFC 2246
<p><br></td></tr><tr align="left"><td valign="top" width="45%"><code>TLS_RSA_EXPORT_ARCFOUR_40_MD5</code>
</td><td valign="top" width="20%">0x00 0x03
</td><td valign="top" width="35%">RFC 2246
<p><br></td></tr><tr align="left"><td valign="top" width="45%"><code>TLS_DHE_DSS_3DES_EDE_CBC_SHA</code>
</td><td valign="top" width="20%">0x00 0x13
</td><td valign="top" width="35%">RFC 2246
<p><br></td></tr><tr align="left"><td valign="top" width="45%"><code>TLS_DHE_RSA_3DES_EDE_CBC_SHA</code>
</td><td valign="top" width="20%">0x00 0x16
</td><td valign="top" width="35%">RFC 2246
<p><br></td></tr><tr align="left"><td valign="top" width="45%"><code>TLS_RSA_AES_128_CBC_SHA</code>
</td><td valign="top" width="20%">0x00 0x2F
</td><td valign="top" width="35%">RFC 3268
<p><br></td></tr><tr align="left"><td valign="top" width="45%"><code>TLS_RSA_AES_256_CBC_SHA</code>
</td><td valign="top" width="20%">0x00 0x35
</td><td valign="top" width="35%">RFC 3268
<p><br></td></tr><tr align="left"><td valign="top" width="45%"><code>TLS_DHE_DSS_AES_256_CBC_SHA</code>
</td><td valign="top" width="20%">0x00 0x38
</td><td valign="top" width="35%">RFC 3268
<p><br></td></tr><tr align="left"><td valign="top" width="45%"><code>TLS_DHE_DSS_AES_128_CBC_SHA</code>
</td><td valign="top" width="20%">0x00 0x32
</td><td valign="top" width="35%">RFC 3268
<p><br></td></tr><tr align="left"><td valign="top" width="45%"><code>TLS_DHE_RSA_AES_256_CBC_SHA</code>
</td><td valign="top" width="20%">0x00 0x39
</td><td valign="top" width="35%">RFC 3268
<p><br></td></tr><tr align="left"><td valign="top" width="45%"><code>TLS_DHE_RSA_AES_128_CBC_SHA</code>
</td><td valign="top" width="20%">0x00 0x33
</td><td valign="top" width="35%">RFC 3268
<p><br></td></tr><tr align="left"><td valign="top" width="45%"><code>TLS_SRP_SHA_3DES_EDE_CBC_SHA</code>
</td><td valign="top" width="20%">0x00 0x50
</td><td valign="top" width="35%">draft-ietf-tls-srp
<p><br></td></tr><tr align="left"><td valign="top" width="45%"><code>TLS_SRP_SHA_AES_128_CBC_SHA</code>
</td><td valign="top" width="20%">0x00 0x53
</td><td valign="top" width="35%">draft-ietf-tls-srp
<p><br></td></tr><tr align="left"><td valign="top" width="45%"><code>TLS_SRP_SHA_AES_256_CBC_SHA</code>
</td><td valign="top" width="20%">0x00 0x56
</td><td valign="top" width="35%">draft-ietf-tls-srp
<p><br></td></tr><tr align="left"><td valign="top" width="45%"><code>TLS_SRP_SHA_RSA_3DES_EDE_CBC_SHA</code>
</td><td valign="top" width="20%">0x00 0x51
</td><td valign="top" width="35%">draft-ietf-tls-srp
<p><br></td></tr><tr align="left"><td valign="top" width="45%"><code>TLS_SRP_SHA_DSS_3DES_EDE_CBC_SHA</code>
</td><td valign="top" width="20%">0x00 0x52
</td><td valign="top" width="35%">draft-ietf-tls-srp
<p><br></td></tr><tr align="left"><td valign="top" width="45%"><code>TLS_SRP_SHA_RSA_AES_128_CBC_SHA</code>
</td><td valign="top" width="20%">0x00 0x54
</td><td valign="top" width="35%">draft-ietf-tls-srp
<p><br></td></tr><tr align="left"><td valign="top" width="45%"><code>TLS_SRP_SHA_DSS_AES_128_CBC_SHA</code>
</td><td valign="top" width="20%">0x00 0x55
</td><td valign="top" width="35%">draft-ietf-tls-srp
<p><br></td></tr><tr align="left"><td valign="top" width="45%"><code>TLS_SRP_SHA_RSA_AES_256_CBC_SHA</code>
</td><td valign="top" width="20%">0x00 0x57
</td><td valign="top" width="35%">draft-ietf-tls-srp
<p><br></td></tr><tr align="left"><td valign="top" width="45%"><code>TLS_SRP_SHA_DSS_AES_256_CBC_SHA</code>
</td><td valign="top" width="20%">0x00 0x58
</td><td valign="top" width="35%">draft-ietf-tls-srp
<p><br></td></tr><tr align="left"><td valign="top" width="45%"><code>TLS_DHE_DSS_ARCFOUR_SHA</code>
</td><td valign="top" width="20%">0x00 0x66
</td><td valign="top" width="35%">draft-ietf-tls-56-bit-ciphersuites
<p><br></td></tr><tr align="left"><td valign="top" width="45%"><code>TLS_PSK_ARCFOUR_SHA</code>
</td><td valign="top" width="20%">0x00 0x8A
</td><td valign="top" width="35%">draft-ietf-tls-psk
<p><br></td></tr><tr align="left"><td valign="top" width="45%"><code>TLS_PSK_3DES_EDE_CBC_SHA</code>
</td><td valign="top" width="20%">0x00 0x8B
</td><td valign="top" width="35%">draft-ietf-tls-psk
<p><br></td></tr><tr align="left"><td valign="top" width="45%"><code>TLS_PSK_AES_128_CBC_SHA</code>
</td><td valign="top" width="20%">0x00 0x8C
</td><td valign="top" width="35%">draft-ietf-tls-psk
<p><br></td></tr><tr align="left"><td valign="top" width="45%"><code>TLS_PSK_AES_256_CBC_SHA</code>
</td><td valign="top" width="20%">0x00 0x8D
</td><td valign="top" width="35%">draft-ietf-tls-psk
<br></td></tr></table>
<div class="node">
<p><hr>
<a name="Internal-architecture-of-GnuTLS"></a>
Next: <a rel="next" accesskey="n" href="#Copying-This-Manual">Copying This Manual</a>,
Previous: <a rel="previous" accesskey="p" href="#All-the-supported-ciphersuites-in-GnuTLS">All the supported ciphersuites in GnuTLS</a>,
Up: <a rel="up" accesskey="u" href="#Top">Top</a>
</div>
<h2 class="chapter">12 Internal architecture of GnuTLS</h2>
<p><a name="index-Internal-architecture-446"></a>
<p>This chapter is to give a brief description of the
way <acronym>GnuTLS</acronym> works. The focus is to give an idea
to potential developers and those who want to know what
happens inside the black box.
<h3 class="section">12.1 The TLS protocol</h3>
<p>The main needs for the TLS protocol to be used are
shown in the image below.
<div class="block-image"><img src="arch/client-server-use-case.png" alt="arch/client-server-use-case.png"></div>
<p>This is being accomplished by the following object diagram.
Note that since <acronym>GnuTLS</acronym> is being developed in C
object are just structures with attributes. The operations listed
are functions that require the first parameter to be that object.
<img src="arch/objects.png" alt="arch/objects.png">
<h3 class="section">12.2 TLS Handshake protocol</h3>
<p>The <acronym>GnuTLS</acronym> 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 the following
figure.
<div class="block-image"><img src="arch/handshake-state.png" alt="arch/handshake-state.png"></div>
<p>Also the way the input is processed varies per ciphersuite. Several
implementations of the internal handlers are available and
<a href="#gnutls_005fhandshake">gnutls_handshake</a> only multiplexes the input to the appropriate
handler. For example a <acronym>PSK</acronym> ciphersuite has a different
implementation of the <code>process_client_key_exchange</code> than a
certificate ciphersuite.
<div class="block-image"><img src="arch/handshake-sequence.png" alt="arch/handshake-sequence.png"></div>
<h3 class="section">12.3 TLS authentication methods</h3>
<p>In <acronym>GnuTLS</acronym> 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
only to implement the functions as seen in the figure below.
<div class="block-image"><img src="arch/mod_auth_st.png" alt="arch/mod_auth_st.png"></div>
<p>The functions that need to be implemented are the ones responsible for interpreting
the handshake protocol messages. It is common for such functions to read data from
one or more <code>credentials_t</code> structures<a rel="footnote" href="#fn-17" name="fnd-17"><sup>17</sup></a> and write data, such as certificates, usernames etc. to <code>auth_info_t</code> structures.
<p>Simple examples of existing authentication methods can be seen in <code>auth_psk.c</code>
for PSK ciphersuites and <code>auth_srp.c</code> for SRP ciphersuites. After implementing these functions
the structure holding its pointers has to be registered in <code>gnutls_algorithms.c</code>
in the <code>_gnutls_kx_algorithms</code> structure.
<h3 class="section">12.4 TLS Extension handling</h3>
<p>As with authentication methods, the TLS extensions handlers can be implemented
using the following interface.
<div class="block-image"><img src="arch/extensions_st.png" alt="arch/extensions_st.png"></div>
<p>Here there are two functions, one for receiving the extension data
and one for sending. These functions have to check internally whether
they operate in client or server side.
<p>A simple example of an extension handler can be seen in <code>ext_srp.c</code>
After implementing these functions, together with the extension number they
handle, they have to be registered in <code>gnutls_extensions.c</code> in the
<code>_gnutls_extensions</code> structure.
<h3 class="section">12.5 Certificate handling</h3>
<p>What is provided by the certificate handling functions
is summarized in the following diagram.
<div class="block-image"><img src="arch/certificate-user-use-case.png" alt="arch/certificate-user-use-case.png"></div>
<div class="node">
<p><hr>
<a name="Copying-This-Manual"></a>
Next: <a rel="next" accesskey="n" href="#Concept-Index">Concept Index</a>,
Previous: <a rel="previous" accesskey="p" href="#Internal-architecture-of-GnuTLS">Internal architecture of GnuTLS</a>,
Up: <a rel="up" accesskey="u" href="#Top">Top</a>
</div>
<h2 class="appendix">Appendix A Copying This Manual</h2>
<ul class="menu">
<li><a accesskey="1" href="#GNU-Free-Documentation-License">GNU Free Documentation License</a>: License for copying this manual.
</ul>
<div class="node">
<p><hr>
<a name="GNU-Free-Documentation-License"></a>
Up: <a rel="up" accesskey="u" href="#Copying-This-Manual">Copying This Manual</a>
</div>
<h3 class="appendixsec">A.1 GNU Free Documentation License</h3>
<p><a name="index-FDL_002c-GNU-Free-Documentation-License-447"></a><div align="center">Version 1.2, November 2002</div>
<pre class="display"> Copyright © 2000,2001,2002 Free Software Foundation, Inc.
51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.
</pre>
<ol type=1 start=0>
<li>PREAMBLE
<p>The purpose of this License is to make a manual, textbook, or other
functional and useful document <dfn>free</dfn> in the sense of freedom: to
assure everyone the effective freedom to copy and redistribute it,
with or without modifying it, either commercially or noncommercially.
Secondarily, this License preserves for the author and publisher a way
to get credit for their work, while not being considered responsible
for modifications made by others.
<p>This License is a kind of “copyleft”, which means that derivative
works of the document must themselves be free in the same sense. It
complements the GNU General Public License, which is a copyleft
license designed for free software.
<p>We have designed this License in order to use it for manuals for free
software, because free software needs free documentation: a free
program should come with manuals providing the same freedoms that the
software does. But this License is not limited to software manuals;
it can be used for any textual work, regardless of subject matter or
whether it is published as a printed book. We recommend this License
principally for works whose purpose is instruction or reference.
<li>APPLICABILITY AND DEFINITIONS
<p>This License applies to any manual or other work, in any medium, that
contains a notice placed by the copyright holder saying it can be
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world-wide, royalty-free license, unlimited in duration, to use that
work under the conditions stated herein. The “Document”, below,
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copy, modify or distribute the work in a way requiring permission
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<p>A “Modified Version” of the Document means any work containing the
Document or a portion of it, either copied verbatim, or with
modifications and/or translated into another language.
<p>A “Secondary Section” is a named appendix or a front-matter section
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<p>The “Invariant Sections” are certain Secondary Sections whose titles
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<p>The “Cover Texts” are certain short passages of text that are listed,
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<p>A “Transparent” copy of the Document means a machine-readable copy,
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<h4 class="appendixsubsec">A.1.1 ADDENDUM: How to use this License for your documents</h4>
<p>To use this License in a document you have written, include a copy of
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<!-- Local Variables: -->
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<div class="node">
<p><hr>
<a name="Concept-Index"></a>
Next: <a rel="next" accesskey="n" href="#Function-and-Data-Index">Function and Data Index</a>,
Previous: <a rel="previous" accesskey="p" href="#Copying-This-Manual">Copying This Manual</a>,
Up: <a rel="up" accesskey="u" href="#Top">Top</a>
</div>
<h2 class="unnumbered">Concept Index</h2>
<ul class="index-cp" compact>
<li><a href="#index-Alert-protocol-7">Alert protocol</a>: <a href="#The-TLS-Alert-Protocol">The TLS Alert Protocol</a></li>
<li><a href="#index-Anonymous-authentication-20">Anonymous authentication</a>: <a href="#Anonymous-authentication">Anonymous authentication</a></li>
<li><a href="#index-Callback-functions-1">Callback functions</a>: <a href="#Callback-functions">Callback functions</a></li>
<li><a href="#index-Certificate-authentication-23">Certificate authentication</a>: <a href="#More-on-certificate-authentication">More on certificate authentication</a></li>
<li><a href="#index-Certificate-requests-27">Certificate requests</a>: <a href="#PKCS-_002310-certificate-requests">PKCS #10 certificate requests</a></li>
<li><a href="#index-Certificate-to-XML-convertion-444">Certificate to XML convertion</a>: <a href="#Certificate-to-XML-convertion-functions">Certificate to XML convertion functions</a></li>
<li><a href="#index-certtool-39">certtool</a>: <a href="#Invoking-certtool">Invoking certtool</a></li>
<li><a href="#index-Ciphersuites-445">Ciphersuites</a>: <a href="#All-the-supported-ciphersuites-in-GnuTLS">All the supported ciphersuites in GnuTLS</a></li>
<li><a href="#index-Client-Certificate-authentication-9">Client Certificate authentication</a>: <a href="#The-TLS-Handshake-Protocol">The TLS Handshake Protocol</a></li>
<li><a href="#index-Compression-algorithms-6">Compression algorithms</a>: <a href="#Compression-algorithms-used-in-the-record-layer">Compression algorithms used in the record layer</a></li>
<li><a href="#index-Digital-signatures-31">Digital signatures</a>: <a href="#Digital-signatures">Digital signatures</a></li>
<li><a href="#index-Error-codes-443">Error codes</a>: <a href="#Error-codes-and-descriptions">Error codes and descriptions</a></li>
<li><a href="#index-Example-programs-32">Example programs</a>: <a href="#How-to-use-GnuTLS-in-applications">How to use GnuTLS in applications</a></li>
<li><a href="#index-FDL_002c-GNU-Free-Documentation-License-447">FDL, GNU Free Documentation License</a>: <a href="#GNU-Free-Documentation-License">GNU Free Documentation License</a></li>
<li><a href="#index-Function-reference-40">Function reference</a>: <a href="#Function-reference">Function reference</a></li>
<li><a href="#index-gnutls_002dcli-36">gnutls-cli</a>: <a href="#Invoking-gnutls_002dcli">Invoking gnutls-cli</a></li>
<li><a href="#index-gnutls_002dcli_002ddebug-37">gnutls-cli-debug</a>: <a href="#Invoking-gnutls_002dcli_002ddebug">Invoking gnutls-cli-debug</a></li>
<li><a href="#index-g_t_0040acronym_007bGnuTLS_002dextra_007d-functions-381"><acronym>GnuTLS-extra</acronym> functions</a>: <a href="#GnuTLS_002dextra-functions">GnuTLS-extra functions</a></li>
<li><a href="#index-gnutls_002dserv-38">gnutls-serv</a>: <a href="#Invoking-gnutls_002dserv">Invoking gnutls-serv</a></li>
<li><a href="#index-Handshake-protocol-8">Handshake protocol</a>: <a href="#The-TLS-Handshake-Protocol">The TLS Handshake Protocol</a></li>
<li><a href="#index-Inner-Application-_0028_0040acronym_007bTLS_002fIA_007d_0029-functions-422">Inner Application (<acronym>TLS/IA</acronym>) functions</a>: <a href="#TLS-Inner-Application-_0028TLS_002fIA_0029-functions">TLS Inner Application (TLS/IA) functions</a></li>
<li><a href="#index-Internal-architecture-446">Internal architecture</a>: <a href="#Internal-architecture-of-GnuTLS">Internal architecture of GnuTLS</a></li>
<li><a href="#index-Maximum-fragment-length-13">Maximum fragment length</a>: <a href="#TLS-Extensions">TLS Extensions</a></li>
<li><a href="#index-g_t_0040acronym_007bOpenPGP_007d-functions-384"><acronym>OpenPGP</acronym> functions</a>: <a href="#OpenPGP-functions">OpenPGP functions</a></li>
<li><a href="#index-g_t_0040acronym_007bOpenPGP_007d-Keys-30"><acronym>OpenPGP</acronym> Keys</a>: <a href="#The-OpenPGP-trust-model">The OpenPGP trust model</a></li>
<li><a href="#index-g_t_0040acronym_007bOpenPGP_007d-Keys-19"><acronym>OpenPGP</acronym> Keys</a>: <a href="#Certificate-authentication">Certificate authentication</a></li>
<li><a href="#index-g_t_0040acronym_007bOpenPGP_007d-Server-33"><acronym>OpenPGP</acronym> Server</a>: <a href="#Echo-Server-with-OpenPGP-authentication">Echo Server with OpenPGP authentication</a></li>
<li><a href="#index-OpenSSL-34">OpenSSL</a>: <a href="#Compatibility-with-the-OpenSSL-library">Compatibility with the OpenSSL library</a></li>
<li><a href="#index-PCT-17">PCT</a>: <a href="#On-SSL-2-and-older-protocols">On SSL 2 and older protocols</a></li>
<li><a href="#index-g_t_0040acronym_007bPKCS_007d-_002310-28"><acronym>PKCS</acronym> #10</a>: <a href="#PKCS-_002310-certificate-requests">PKCS #10 certificate requests</a></li>
<li><a href="#index-g_t_0040acronym_007bPKCS_007d-_002312-29"><acronym>PKCS</acronym> #12</a>: <a href="#PKCS-_002312-structures">PKCS #12 structures</a></li>
<li><a href="#index-g_t_0040acronym_007bPSK_007d-authentication-22"><acronym>PSK</acronym> authentication</a>: <a href="#Authentication-using-PSK">Authentication using PSK</a></li>
<li><a href="#index-Record-protocol-4">Record protocol</a>: <a href="#The-TLS-record-protocol">The TLS record protocol</a></li>
<li><a href="#index-Resuming-sessions-10">Resuming sessions</a>: <a href="#The-TLS-Handshake-Protocol">The TLS Handshake Protocol</a></li>
<li><a href="#index-Server-name-indication-15">Server name indication</a>: <a href="#TLS-Extensions">TLS Extensions</a></li>
<li><a href="#index-g_t_0040acronym_007bSRP_007d-authentication-21"><acronym>SRP</acronym> authentication</a>: <a href="#Authentication-using-SRP">Authentication using SRP</a></li>
<li><a href="#index-srptool-35">srptool</a>: <a href="#Invoking-srptool">Invoking srptool</a></li>
<li><a href="#index-SSL-2-16">SSL 2</a>: <a href="#On-SSL-2-and-older-protocols">On SSL 2 and older protocols</a></li>
<li><a href="#index-Symmetric-encryption-algorithms-5">Symmetric encryption algorithms</a>: <a href="#Encryption-algorithms-used-in-the-record-layer">Encryption algorithms used in the record layer</a></li>
<li><a href="#index-TLS-Extensions-11">TLS Extensions</a>: <a href="#TLS-Extensions">TLS Extensions</a></li>
<li><a href="#index-g_t_0040acronym_007bTLS_007d-Inner-Application-_0028_0040acronym_007bTLS_002fIA_007d_0029-functions-421"><acronym>TLS</acronym> Inner Application (<acronym>TLS/IA</acronym>) functions</a>: <a href="#TLS-Inner-Application-_0028TLS_002fIA_0029-functions">TLS Inner Application (TLS/IA) functions</a></li>
<li><a href="#index-TLS-Layers-2">TLS Layers</a>: <a href="#TLS-layers">TLS layers</a></li>
<li><a href="#index-Transport-protocol-3">Transport protocol</a>: <a href="#The-transport-layer">The transport layer</a></li>
<li><a href="#index-Verifying-certificate-paths-25">Verifying certificate paths</a>: <a href="#Verifying-X_002e509-certificate-paths">Verifying X.509 certificate paths</a></li>
<li><a href="#index-g_t_0040acronym_007bX_002e509_007d-certificates-24"><acronym>X.509</acronym> certificates</a>: <a href="#The-X_002e509-trust-model">The X.509 trust model</a></li>
<li><a href="#index-g_t_0040acronym_007bX_002e509_007d-certificates-18"><acronym>X.509</acronym> certificates</a>: <a href="#Certificate-authentication">Certificate authentication</a></li>
<li><a href="#index-g_t_0040acronym_007bX_002e509_007d-Functions-227"><acronym>X.509</acronym> Functions</a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
</ul><div class="node">
<p><hr>
<a name="Function-and-Data-Index"></a>
Next: <a rel="next" accesskey="n" href="#Bibliography">Bibliography</a>,
Previous: <a rel="previous" accesskey="p" href="#Concept-Index">Concept Index</a>,
Up: <a rel="up" accesskey="u" href="#Top">Top</a>
</div>
<h2 class="unnumbered">Function and Data Index</h2>
<ul class="index-fn" compact>
<li><a href="#index-gnutls_005falert_005fget-42"><code>gnutls_alert_get</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005falert_005fget_005fname-41"><code>gnutls_alert_get_name</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005falert_005fsend-44"><code>gnutls_alert_send</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005falert_005fsend_005fappropriate-43"><code>gnutls_alert_send_appropriate</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fanon_005fallocate_005fclient_005fcredentials-45"><code>gnutls_anon_allocate_client_credentials</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fanon_005fallocate_005fserver_005fcredentials-46"><code>gnutls_anon_allocate_server_credentials</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fanon_005ffree_005fclient_005fcredentials-47"><code>gnutls_anon_free_client_credentials</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fanon_005ffree_005fserver_005fcredentials-48"><code>gnutls_anon_free_server_credentials</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fanon_005fset_005fparams_005ffunction-49"><code>gnutls_anon_set_params_function</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fanon_005fset_005fserver_005fdh_005fparams-50"><code>gnutls_anon_set_server_dh_params</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fanon_005fset_005fserver_005fparams_005ffunction-51"><code>gnutls_anon_set_server_params_function</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fauth_005fclient_005fget_005ftype-52"><code>gnutls_auth_client_get_type</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fauth_005fget_005ftype-53"><code>gnutls_auth_get_type</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fauth_005fserver_005fget_005ftype-54"><code>gnutls_auth_server_get_type</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fbye-55"><code>gnutls_bye</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcertificate_005factivation_005ftime_005fpeers-56"><code>gnutls_certificate_activation_time_peers</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcertificate_005fallocate_005fcredentials-57"><code>gnutls_certificate_allocate_credentials</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcertificate_005fclient_005fget_005frequest_005fstatus-58"><code>gnutls_certificate_client_get_request_status</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcertificate_005fclient_005fset_005fretrieve_005ffunction-59"><code>gnutls_certificate_client_set_retrieve_function</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcertificate_005fexpiration_005ftime_005fpeers-60"><code>gnutls_certificate_expiration_time_peers</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcertificate_005ffree_005fca_005fnames-61"><code>gnutls_certificate_free_ca_names</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcertificate_005ffree_005fcas-62"><code>gnutls_certificate_free_cas</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcertificate_005ffree_005fcredentials-63"><code>gnutls_certificate_free_credentials</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcertificate_005ffree_005fcrls-64"><code>gnutls_certificate_free_crls</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcertificate_005ffree_005fkeys-65"><code>gnutls_certificate_free_keys</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcertificate_005fget_005fours-66"><code>gnutls_certificate_get_ours</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcertificate_005fget_005fpeers-67"><code>gnutls_certificate_get_peers</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcertificate_005fsend_005fx509_005frdn_005fsequence-68"><code>gnutls_certificate_send_x509_rdn_sequence</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcertificate_005fserver_005fset_005frequest-69"><code>gnutls_certificate_server_set_request</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcertificate_005fserver_005fset_005fretrieve_005ffunction-70"><code>gnutls_certificate_server_set_retrieve_function</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcertificate_005fset_005fdh_005fparams-71"><code>gnutls_certificate_set_dh_params</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcertificate_005fset_005fopenpgp_005fkey-390"><code>gnutls_certificate_set_openpgp_key</code></a>: <a href="#OpenPGP-functions">OpenPGP functions</a></li>
<li><a href="#index-gnutls_005fcertificate_005fset_005fopenpgp_005fkey_005ffile-385"><code>gnutls_certificate_set_openpgp_key_file</code></a>: <a href="#OpenPGP-functions">OpenPGP functions</a></li>
<li><a href="#index-gnutls_005fcertificate_005fset_005fopenpgp_005fkey_005fmem-386"><code>gnutls_certificate_set_openpgp_key_mem</code></a>: <a href="#OpenPGP-functions">OpenPGP functions</a></li>
<li><a href="#index-gnutls_005fcertificate_005fset_005fopenpgp_005fkeyring_005ffile-387"><code>gnutls_certificate_set_openpgp_keyring_file</code></a>: <a href="#OpenPGP-functions">OpenPGP functions</a></li>
<li><a href="#index-gnutls_005fcertificate_005fset_005fopenpgp_005fkeyring_005fmem-388"><code>gnutls_certificate_set_openpgp_keyring_mem</code></a>: <a href="#OpenPGP-functions">OpenPGP functions</a></li>
<li><a href="#index-gnutls_005fcertificate_005fset_005fopenpgp_005fkeyserver-389"><code>gnutls_certificate_set_openpgp_keyserver</code></a>: <a href="#OpenPGP-functions">OpenPGP functions</a></li>
<li><a href="#index-gnutls_005fcertificate_005fset_005fopenpgp_005ftrustdb-391"><code>gnutls_certificate_set_openpgp_trustdb</code></a>: <a href="#OpenPGP-functions">OpenPGP functions</a></li>
<li><a href="#index-gnutls_005fcertificate_005fset_005fparams_005ffunction-72"><code>gnutls_certificate_set_params_function</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcertificate_005fset_005frsa_005fexport_005fparams-73"><code>gnutls_certificate_set_rsa_export_params</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcertificate_005fset_005fverify_005fflags-74"><code>gnutls_certificate_set_verify_flags</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcertificate_005fset_005fverify_005flimits-75"><code>gnutls_certificate_set_verify_limits</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcertificate_005fset_005fx509_005fcrl-78"><code>gnutls_certificate_set_x509_crl</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcertificate_005fset_005fx509_005fcrl_005ffile-76"><code>gnutls_certificate_set_x509_crl_file</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcertificate_005fset_005fx509_005fcrl_005fmem-77"><code>gnutls_certificate_set_x509_crl_mem</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcertificate_005fset_005fx509_005fkey-81"><code>gnutls_certificate_set_x509_key</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcertificate_005fset_005fx509_005fkey_005ffile-79"><code>gnutls_certificate_set_x509_key_file</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcertificate_005fset_005fx509_005fkey_005fmem-80"><code>gnutls_certificate_set_x509_key_mem</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcertificate_005fset_005fx509_005fsimple_005fpkcs12_005ffile-82"><code>gnutls_certificate_set_x509_simple_pkcs12_file</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcertificate_005fset_005fx509_005ftrust-85"><code>gnutls_certificate_set_x509_trust</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcertificate_005fset_005fx509_005ftrust_005ffile-83"><code>gnutls_certificate_set_x509_trust_file</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcertificate_005fset_005fx509_005ftrust_005fmem-84"><code>gnutls_certificate_set_x509_trust_mem</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcertificate_005ftype_005fget-87"><code>gnutls_certificate_type_get</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcertificate_005ftype_005fget_005fname-86"><code>gnutls_certificate_type_get_name</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcertificate_005ftype_005fset_005fpriority-88"><code>gnutls_certificate_type_set_priority</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcertificate_005fverify_005fflags-26"><code>gnutls_certificate_verify_flags</code></a>: <a href="#Verifying-X_002e509-certificate-paths">Verifying X.509 certificate paths</a></li>
<li><a href="#index-gnutls_005fcertificate_005fverify_005fpeers-90"><code>gnutls_certificate_verify_peers</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcertificate_005fverify_005fpeers2-89"><code>gnutls_certificate_verify_peers2</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcheck_005fversion-91"><code>gnutls_check_version</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcipher_005fget-94"><code>gnutls_cipher_get</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcipher_005fget_005fkey_005fsize-92"><code>gnutls_cipher_get_key_size</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcipher_005fget_005fname-93"><code>gnutls_cipher_get_name</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcipher_005fset_005fpriority-95"><code>gnutls_cipher_set_priority</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcipher_005fsuite_005fget_005fname-96"><code>gnutls_cipher_suite_get_name</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcompression_005fget-98"><code>gnutls_compression_get</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcompression_005fget_005fname-97"><code>gnutls_compression_get_name</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcompression_005fset_005fpriority-99"><code>gnutls_compression_set_priority</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcredentials_005fclear-100"><code>gnutls_credentials_clear</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fcredentials_005fset-101"><code>gnutls_credentials_set</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fdb_005fcheck_005fentry-102"><code>gnutls_db_check_entry</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fdb_005fget_005fptr-103"><code>gnutls_db_get_ptr</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fdb_005fremove_005fsession-104"><code>gnutls_db_remove_session</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fdb_005fset_005fcache_005fexpiration-105"><code>gnutls_db_set_cache_expiration</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fdb_005fset_005fptr-106"><code>gnutls_db_set_ptr</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fdb_005fset_005fremove_005ffunction-107"><code>gnutls_db_set_remove_function</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fdb_005fset_005fretrieve_005ffunction-108"><code>gnutls_db_set_retrieve_function</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fdb_005fset_005fstore_005ffunction-109"><code>gnutls_db_set_store_function</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fdeinit-110"><code>gnutls_deinit</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fdh_005fget_005fgroup-111"><code>gnutls_dh_get_group</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fdh_005fget_005fpeers_005fpublic_005fbits-112"><code>gnutls_dh_get_peers_public_bits</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fdh_005fget_005fprime_005fbits-113"><code>gnutls_dh_get_prime_bits</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fdh_005fget_005fpubkey-114"><code>gnutls_dh_get_pubkey</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fdh_005fget_005fsecret_005fbits-115"><code>gnutls_dh_get_secret_bits</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fdh_005fparams_005fcpy-116"><code>gnutls_dh_params_cpy</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fdh_005fparams_005fdeinit-117"><code>gnutls_dh_params_deinit</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fdh_005fparams_005fexport_005fpkcs3-118"><code>gnutls_dh_params_export_pkcs3</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fdh_005fparams_005fexport_005fraw-119"><code>gnutls_dh_params_export_raw</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fdh_005fparams_005fgenerate2-120"><code>gnutls_dh_params_generate2</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fdh_005fparams_005fimport_005fpkcs3-121"><code>gnutls_dh_params_import_pkcs3</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fdh_005fparams_005fimport_005fraw-122"><code>gnutls_dh_params_import_raw</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fdh_005fparams_005finit-123"><code>gnutls_dh_params_init</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fdh_005fset_005fprime_005fbits-124"><code>gnutls_dh_set_prime_bits</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005ferror_005fis_005ffatal-125"><code>gnutls_error_is_fatal</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005ferror_005fto_005falert-126"><code>gnutls_error_to_alert</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fextra_005fcheck_005fversion-382"><code>gnutls_extra_check_version</code></a>: <a href="#GnuTLS_002dextra-functions">GnuTLS-extra functions</a></li>
<li><a href="#index-gnutls_005ffingerprint-127"><code>gnutls_fingerprint</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005ffree-128"><code>gnutls_free</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fglobal_005fdeinit-129"><code>gnutls_global_deinit</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fglobal_005finit-130"><code>gnutls_global_init</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fglobal_005finit_005fextra-383"><code>gnutls_global_init_extra</code></a>: <a href="#GnuTLS_002dextra-functions">GnuTLS-extra functions</a></li>
<li><a href="#index-gnutls_005fglobal_005fset_005flog_005ffunction-131"><code>gnutls_global_set_log_function</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fglobal_005fset_005flog_005flevel-132"><code>gnutls_global_set_log_level</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fglobal_005fset_005fmem_005ffunctions-133"><code>gnutls_global_set_mem_functions</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fhandshake-138"><code>gnutls_handshake</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fhandshake_005fget_005flast_005fin-134"><code>gnutls_handshake_get_last_in</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fhandshake_005fget_005flast_005fout-135"><code>gnutls_handshake_get_last_out</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fhandshake_005fset_005fmax_005fpacket_005flength-136"><code>gnutls_handshake_set_max_packet_length</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fhandshake_005fset_005fprivate_005fextensions-137"><code>gnutls_handshake_set_private_extensions</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fhex_005fdecode-139"><code>gnutls_hex_decode</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fhex_005fencode-140"><code>gnutls_hex_encode</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fia_005fallocate_005fclient_005fcredentials-423"><code>gnutls_ia_allocate_client_credentials</code></a>: <a href="#TLS-Inner-Application-_0028TLS_002fIA_0029-functions">TLS Inner Application (TLS/IA) functions</a></li>
<li><a href="#index-gnutls_005fia_005fallocate_005fserver_005fcredentials-424"><code>gnutls_ia_allocate_server_credentials</code></a>: <a href="#TLS-Inner-Application-_0028TLS_002fIA_0029-functions">TLS Inner Application (TLS/IA) functions</a></li>
<li><a href="#index-gnutls_005fia_005fenable-425"><code>gnutls_ia_enable</code></a>: <a href="#TLS-Inner-Application-_0028TLS_002fIA_0029-functions">TLS Inner Application (TLS/IA) functions</a></li>
<li><a href="#index-gnutls_005fia_005fendphase_005fsend-426"><code>gnutls_ia_endphase_send</code></a>: <a href="#TLS-Inner-Application-_0028TLS_002fIA_0029-functions">TLS Inner Application (TLS/IA) functions</a></li>
<li><a href="#index-gnutls_005fia_005fextract_005finner_005fsecret-427"><code>gnutls_ia_extract_inner_secret</code></a>: <a href="#TLS-Inner-Application-_0028TLS_002fIA_0029-functions">TLS Inner Application (TLS/IA) functions</a></li>
<li><a href="#index-gnutls_005fia_005ffree_005fclient_005fcredentials-428"><code>gnutls_ia_free_client_credentials</code></a>: <a href="#TLS-Inner-Application-_0028TLS_002fIA_0029-functions">TLS Inner Application (TLS/IA) functions</a></li>
<li><a href="#index-gnutls_005fia_005ffree_005fserver_005fcredentials-429"><code>gnutls_ia_free_server_credentials</code></a>: <a href="#TLS-Inner-Application-_0028TLS_002fIA_0029-functions">TLS Inner Application (TLS/IA) functions</a></li>
<li><a href="#index-gnutls_005fia_005fgenerate_005fchallenge-430"><code>gnutls_ia_generate_challenge</code></a>: <a href="#TLS-Inner-Application-_0028TLS_002fIA_0029-functions">TLS Inner Application (TLS/IA) functions</a></li>
<li><a href="#index-gnutls_005fia_005fget_005fclient_005favp_005fptr-431"><code>gnutls_ia_get_client_avp_ptr</code></a>: <a href="#TLS-Inner-Application-_0028TLS_002fIA_0029-functions">TLS Inner Application (TLS/IA) functions</a></li>
<li><a href="#index-gnutls_005fia_005fget_005fserver_005favp_005fptr-432"><code>gnutls_ia_get_server_avp_ptr</code></a>: <a href="#TLS-Inner-Application-_0028TLS_002fIA_0029-functions">TLS Inner Application (TLS/IA) functions</a></li>
<li><a href="#index-gnutls_005fia_005fhandshake-434"><code>gnutls_ia_handshake</code></a>: <a href="#TLS-Inner-Application-_0028TLS_002fIA_0029-functions">TLS Inner Application (TLS/IA) functions</a></li>
<li><a href="#index-gnutls_005fia_005fhandshake_005fp-433"><code>gnutls_ia_handshake_p</code></a>: <a href="#TLS-Inner-Application-_0028TLS_002fIA_0029-functions">TLS Inner Application (TLS/IA) functions</a></li>
<li><a href="#index-gnutls_005fia_005fpermute_005finner_005fsecret-435"><code>gnutls_ia_permute_inner_secret</code></a>: <a href="#TLS-Inner-Application-_0028TLS_002fIA_0029-functions">TLS Inner Application (TLS/IA) functions</a></li>
<li><a href="#index-gnutls_005fia_005frecv-436"><code>gnutls_ia_recv</code></a>: <a href="#TLS-Inner-Application-_0028TLS_002fIA_0029-functions">TLS Inner Application (TLS/IA) functions</a></li>
<li><a href="#index-gnutls_005fia_005fsend-437"><code>gnutls_ia_send</code></a>: <a href="#TLS-Inner-Application-_0028TLS_002fIA_0029-functions">TLS Inner Application (TLS/IA) functions</a></li>
<li><a href="#index-gnutls_005fia_005fset_005fclient_005favp_005ffunction-438"><code>gnutls_ia_set_client_avp_function</code></a>: <a href="#TLS-Inner-Application-_0028TLS_002fIA_0029-functions">TLS Inner Application (TLS/IA) functions</a></li>
<li><a href="#index-gnutls_005fia_005fset_005fclient_005favp_005fptr-439"><code>gnutls_ia_set_client_avp_ptr</code></a>: <a href="#TLS-Inner-Application-_0028TLS_002fIA_0029-functions">TLS Inner Application (TLS/IA) functions</a></li>
<li><a href="#index-gnutls_005fia_005fset_005fserver_005favp_005ffunction-440"><code>gnutls_ia_set_server_avp_function</code></a>: <a href="#TLS-Inner-Application-_0028TLS_002fIA_0029-functions">TLS Inner Application (TLS/IA) functions</a></li>
<li><a href="#index-gnutls_005fia_005fset_005fserver_005favp_005fptr-441"><code>gnutls_ia_set_server_avp_ptr</code></a>: <a href="#TLS-Inner-Application-_0028TLS_002fIA_0029-functions">TLS Inner Application (TLS/IA) functions</a></li>
<li><a href="#index-gnutls_005fia_005fverify_005fendphase-442"><code>gnutls_ia_verify_endphase</code></a>: <a href="#TLS-Inner-Application-_0028TLS_002fIA_0029-functions">TLS Inner Application (TLS/IA) functions</a></li>
<li><a href="#index-gnutls_005finit-141"><code>gnutls_init</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fkx_005fget-143"><code>gnutls_kx_get</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fkx_005fget_005fname-142"><code>gnutls_kx_get_name</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fkx_005fset_005fpriority-144"><code>gnutls_kx_set_priority</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fmac_005fget-146"><code>gnutls_mac_get</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fmac_005fget_005fname-145"><code>gnutls_mac_get_name</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fmac_005fset_005fpriority-147"><code>gnutls_mac_set_priority</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fmalloc-148"><code>gnutls_malloc</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fopenpgp_005fkey_005fcheck_005fhostname-392"><code>gnutls_openpgp_key_check_hostname</code></a>: <a href="#OpenPGP-functions">OpenPGP functions</a></li>
<li><a href="#index-gnutls_005fopenpgp_005fkey_005fdeinit-393"><code>gnutls_openpgp_key_deinit</code></a>: <a href="#OpenPGP-functions">OpenPGP functions</a></li>
<li><a href="#index-gnutls_005fopenpgp_005fkey_005fexport-394"><code>gnutls_openpgp_key_export</code></a>: <a href="#OpenPGP-functions">OpenPGP functions</a></li>
<li><a href="#index-gnutls_005fopenpgp_005fkey_005fget_005fcreation_005ftime-395"><code>gnutls_openpgp_key_get_creation_time</code></a>: <a href="#OpenPGP-functions">OpenPGP functions</a></li>
<li><a href="#index-gnutls_005fopenpgp_005fkey_005fget_005fexpiration_005ftime-396"><code>gnutls_openpgp_key_get_expiration_time</code></a>: <a href="#OpenPGP-functions">OpenPGP functions</a></li>
<li><a href="#index-gnutls_005fopenpgp_005fkey_005fget_005ffingerprint-397"><code>gnutls_openpgp_key_get_fingerprint</code></a>: <a href="#OpenPGP-functions">OpenPGP functions</a></li>
<li><a href="#index-gnutls_005fopenpgp_005fkey_005fget_005fid-398"><code>gnutls_openpgp_key_get_id</code></a>: <a href="#OpenPGP-functions">OpenPGP functions</a></li>
<li><a href="#index-gnutls_005fopenpgp_005fkey_005fget_005fkey_005fusage-399"><code>gnutls_openpgp_key_get_key_usage</code></a>: <a href="#OpenPGP-functions">OpenPGP functions</a></li>
<li><a href="#index-gnutls_005fopenpgp_005fkey_005fget_005fname-400"><code>gnutls_openpgp_key_get_name</code></a>: <a href="#OpenPGP-functions">OpenPGP functions</a></li>
<li><a href="#index-gnutls_005fopenpgp_005fkey_005fget_005fpk_005falgorithm-401"><code>gnutls_openpgp_key_get_pk_algorithm</code></a>: <a href="#OpenPGP-functions">OpenPGP functions</a></li>
<li><a href="#index-gnutls_005fopenpgp_005fkey_005fget_005fversion-402"><code>gnutls_openpgp_key_get_version</code></a>: <a href="#OpenPGP-functions">OpenPGP functions</a></li>
<li><a href="#index-gnutls_005fopenpgp_005fkey_005fimport-403"><code>gnutls_openpgp_key_import</code></a>: <a href="#OpenPGP-functions">OpenPGP functions</a></li>
<li><a href="#index-gnutls_005fopenpgp_005fkey_005finit-404"><code>gnutls_openpgp_key_init</code></a>: <a href="#OpenPGP-functions">OpenPGP functions</a></li>
<li><a href="#index-gnutls_005fopenpgp_005fkey_005fto_005fxml-405"><code>gnutls_openpgp_key_to_xml</code></a>: <a href="#OpenPGP-functions">OpenPGP functions</a></li>
<li><a href="#index-gnutls_005fopenpgp_005fkey_005fverify_005fring-406"><code>gnutls_openpgp_key_verify_ring</code></a>: <a href="#OpenPGP-functions">OpenPGP functions</a></li>
<li><a href="#index-gnutls_005fopenpgp_005fkey_005fverify_005fself-407"><code>gnutls_openpgp_key_verify_self</code></a>: <a href="#OpenPGP-functions">OpenPGP functions</a></li>
<li><a href="#index-gnutls_005fopenpgp_005fkey_005fverify_005ftrustdb-408"><code>gnutls_openpgp_key_verify_trustdb</code></a>: <a href="#OpenPGP-functions">OpenPGP functions</a></li>
<li><a href="#index-gnutls_005fopenpgp_005fkeyring_005fcheck_005fid-409"><code>gnutls_openpgp_keyring_check_id</code></a>: <a href="#OpenPGP-functions">OpenPGP functions</a></li>
<li><a href="#index-gnutls_005fopenpgp_005fkeyring_005fdeinit-410"><code>gnutls_openpgp_keyring_deinit</code></a>: <a href="#OpenPGP-functions">OpenPGP functions</a></li>
<li><a href="#index-gnutls_005fopenpgp_005fkeyring_005fimport-411"><code>gnutls_openpgp_keyring_import</code></a>: <a href="#OpenPGP-functions">OpenPGP functions</a></li>
<li><a href="#index-gnutls_005fopenpgp_005fkeyring_005finit-412"><code>gnutls_openpgp_keyring_init</code></a>: <a href="#OpenPGP-functions">OpenPGP functions</a></li>
<li><a href="#index-gnutls_005fopenpgp_005fprivkey_005fdeinit-413"><code>gnutls_openpgp_privkey_deinit</code></a>: <a href="#OpenPGP-functions">OpenPGP functions</a></li>
<li><a href="#index-gnutls_005fopenpgp_005fprivkey_005fget_005fpk_005falgorithm-414"><code>gnutls_openpgp_privkey_get_pk_algorithm</code></a>: <a href="#OpenPGP-functions">OpenPGP functions</a></li>
<li><a href="#index-gnutls_005fopenpgp_005fprivkey_005fimport-415"><code>gnutls_openpgp_privkey_import</code></a>: <a href="#OpenPGP-functions">OpenPGP functions</a></li>
<li><a href="#index-gnutls_005fopenpgp_005fprivkey_005finit-416"><code>gnutls_openpgp_privkey_init</code></a>: <a href="#OpenPGP-functions">OpenPGP functions</a></li>
<li><a href="#index-gnutls_005fopenpgp_005fsend_005fkey-149"><code>gnutls_openpgp_send_key</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fopenpgp_005fset_005frecv_005fkey_005ffunction-417"><code>gnutls_openpgp_set_recv_key_function</code></a>: <a href="#OpenPGP-functions">OpenPGP functions</a></li>
<li><a href="#index-gnutls_005fopenpgp_005ftrustdb_005fdeinit-418"><code>gnutls_openpgp_trustdb_deinit</code></a>: <a href="#OpenPGP-functions">OpenPGP functions</a></li>
<li><a href="#index-gnutls_005fopenpgp_005ftrustdb_005fimport_005ffile-419"><code>gnutls_openpgp_trustdb_import_file</code></a>: <a href="#OpenPGP-functions">OpenPGP functions</a></li>
<li><a href="#index-gnutls_005fopenpgp_005ftrustdb_005finit-420"><code>gnutls_openpgp_trustdb_init</code></a>: <a href="#OpenPGP-functions">OpenPGP functions</a></li>
<li><a href="#index-gnutls_005fpem_005fbase64_005fdecode-151"><code>gnutls_pem_base64_decode</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fpem_005fbase64_005fdecode_005falloc-150"><code>gnutls_pem_base64_decode_alloc</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fpem_005fbase64_005fencode-153"><code>gnutls_pem_base64_encode</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fpem_005fbase64_005fencode_005falloc-152"><code>gnutls_pem_base64_encode_alloc</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fperror-154"><code>gnutls_perror</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fpk_005falgorithm_005fget_005fname-155"><code>gnutls_pk_algorithm_get_name</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fpkcs12_005fbag_005fdecrypt-228"><code>gnutls_pkcs12_bag_decrypt</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fpkcs12_005fbag_005fdeinit-229"><code>gnutls_pkcs12_bag_deinit</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fpkcs12_005fbag_005fencrypt-230"><code>gnutls_pkcs12_bag_encrypt</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fpkcs12_005fbag_005fget_005fcount-231"><code>gnutls_pkcs12_bag_get_count</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fpkcs12_005fbag_005fget_005fdata-232"><code>gnutls_pkcs12_bag_get_data</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fpkcs12_005fbag_005fget_005ffriendly_005fname-233"><code>gnutls_pkcs12_bag_get_friendly_name</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fpkcs12_005fbag_005fget_005fkey_005fid-234"><code>gnutls_pkcs12_bag_get_key_id</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fpkcs12_005fbag_005fget_005ftype-235"><code>gnutls_pkcs12_bag_get_type</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fpkcs12_005fbag_005finit-236"><code>gnutls_pkcs12_bag_init</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fpkcs12_005fbag_005fset_005fcrl-237"><code>gnutls_pkcs12_bag_set_crl</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fpkcs12_005fbag_005fset_005fcrt-238"><code>gnutls_pkcs12_bag_set_crt</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fpkcs12_005fbag_005fset_005fdata-239"><code>gnutls_pkcs12_bag_set_data</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fpkcs12_005fbag_005fset_005ffriendly_005fname-240"><code>gnutls_pkcs12_bag_set_friendly_name</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fpkcs12_005fbag_005fset_005fkey_005fid-241"><code>gnutls_pkcs12_bag_set_key_id</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fpkcs12_005fdeinit-242"><code>gnutls_pkcs12_deinit</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fpkcs12_005fexport-243"><code>gnutls_pkcs12_export</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fpkcs12_005fgenerate_005fmac-244"><code>gnutls_pkcs12_generate_mac</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fpkcs12_005fget_005fbag-245"><code>gnutls_pkcs12_get_bag</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fpkcs12_005fimport-246"><code>gnutls_pkcs12_import</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fpkcs12_005finit-247"><code>gnutls_pkcs12_init</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fpkcs12_005fset_005fbag-248"><code>gnutls_pkcs12_set_bag</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fpkcs12_005fverify_005fmac-249"><code>gnutls_pkcs12_verify_mac</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fpkcs7_005fdeinit-250"><code>gnutls_pkcs7_deinit</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fpkcs7_005fdelete_005fcrl-251"><code>gnutls_pkcs7_delete_crl</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fpkcs7_005fdelete_005fcrt-252"><code>gnutls_pkcs7_delete_crt</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fpkcs7_005fexport-253"><code>gnutls_pkcs7_export</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fpkcs7_005fget_005fcrl_005fcount-254"><code>gnutls_pkcs7_get_crl_count</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fpkcs7_005fget_005fcrl_005fraw-255"><code>gnutls_pkcs7_get_crl_raw</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fpkcs7_005fget_005fcrt_005fcount-256"><code>gnutls_pkcs7_get_crt_count</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fpkcs7_005fget_005fcrt_005fraw-257"><code>gnutls_pkcs7_get_crt_raw</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fpkcs7_005fimport-258"><code>gnutls_pkcs7_import</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fpkcs7_005finit-259"><code>gnutls_pkcs7_init</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fpkcs7_005fset_005fcrl-261"><code>gnutls_pkcs7_set_crl</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fpkcs7_005fset_005fcrl_005fraw-260"><code>gnutls_pkcs7_set_crl_raw</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fpkcs7_005fset_005fcrt-263"><code>gnutls_pkcs7_set_crt</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fpkcs7_005fset_005fcrt_005fraw-262"><code>gnutls_pkcs7_set_crt_raw</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fprf-157"><code>gnutls_prf</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fprf_005fraw-156"><code>gnutls_prf_raw</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fprotocol_005fget_005fname-158"><code>gnutls_protocol_get_name</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fprotocol_005fget_005fversion-159"><code>gnutls_protocol_get_version</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fprotocol_005fset_005fpriority-160"><code>gnutls_protocol_set_priority</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fpsk_005fallocate_005fclient_005fcredentials-161"><code>gnutls_psk_allocate_client_credentials</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fpsk_005fallocate_005fserver_005fcredentials-162"><code>gnutls_psk_allocate_server_credentials</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fpsk_005ffree_005fclient_005fcredentials-163"><code>gnutls_psk_free_client_credentials</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fpsk_005ffree_005fserver_005fcredentials-164"><code>gnutls_psk_free_server_credentials</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fpsk_005fserver_005fget_005fusername-165"><code>gnutls_psk_server_get_username</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fpsk_005fset_005fclient_005fcredentials-167"><code>gnutls_psk_set_client_credentials</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fpsk_005fset_005fclient_005fcredentials_005ffunction-166"><code>gnutls_psk_set_client_credentials_function</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fpsk_005fset_005fparams_005ffunction-168"><code>gnutls_psk_set_params_function</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fpsk_005fset_005fserver_005fcredentials_005ffile-169"><code>gnutls_psk_set_server_credentials_file</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fpsk_005fset_005fserver_005fcredentials_005ffunction-170"><code>gnutls_psk_set_server_credentials_function</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fpsk_005fset_005fserver_005fdh_005fparams-171"><code>gnutls_psk_set_server_dh_params</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fpsk_005fset_005fserver_005fparams_005ffunction-172"><code>gnutls_psk_set_server_params_function</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005frecord_005fcheck_005fpending-173"><code>gnutls_record_check_pending</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005frecord_005fget_005fdirection-174"><code>gnutls_record_get_direction</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005frecord_005fget_005fmax_005fsize-175"><code>gnutls_record_get_max_size</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005frecord_005frecv-176"><code>gnutls_record_recv</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005frecord_005fsend-177"><code>gnutls_record_send</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005frecord_005fset_005fmax_005fsize-178"><code>gnutls_record_set_max_size</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005frehandshake-179"><code>gnutls_rehandshake</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005frsa_005fexport_005fget_005fmodulus_005fbits-180"><code>gnutls_rsa_export_get_modulus_bits</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005frsa_005fexport_005fget_005fpubkey-181"><code>gnutls_rsa_export_get_pubkey</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005frsa_005fparams_005fcpy-182"><code>gnutls_rsa_params_cpy</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005frsa_005fparams_005fdeinit-183"><code>gnutls_rsa_params_deinit</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005frsa_005fparams_005fexport_005fpkcs1-184"><code>gnutls_rsa_params_export_pkcs1</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005frsa_005fparams_005fexport_005fraw-185"><code>gnutls_rsa_params_export_raw</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005frsa_005fparams_005fgenerate2-186"><code>gnutls_rsa_params_generate2</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005frsa_005fparams_005fimport_005fpkcs1-187"><code>gnutls_rsa_params_import_pkcs1</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005frsa_005fparams_005fimport_005fraw-188"><code>gnutls_rsa_params_import_raw</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005frsa_005fparams_005finit-189"><code>gnutls_rsa_params_init</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fserver_005fname_005fget-190"><code>gnutls_server_name_get</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fserver_005fname_005fset-191"><code>gnutls_server_name_set</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fsession_005fget_005fclient_005frandom-192"><code>gnutls_session_get_client_random</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fsession_005fget_005fdata-194"><code>gnutls_session_get_data</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fsession_005fget_005fdata2-193"><code>gnutls_session_get_data2</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fsession_005fget_005fid-195"><code>gnutls_session_get_id</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fsession_005fget_005fmaster_005fsecret-196"><code>gnutls_session_get_master_secret</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fsession_005fget_005fptr-197"><code>gnutls_session_get_ptr</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fsession_005fget_005fserver_005frandom-198"><code>gnutls_session_get_server_random</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fsession_005fis_005fresumed-199"><code>gnutls_session_is_resumed</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fsession_005fset_005fdata-200"><code>gnutls_session_set_data</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fsession_005fset_005fptr-201"><code>gnutls_session_set_ptr</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fset_005fdefault_005fexport_005fpriority-202"><code>gnutls_set_default_export_priority</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fset_005fdefault_005fpriority-203"><code>gnutls_set_default_priority</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fsign_005falgorithm_005fget_005fname-204"><code>gnutls_sign_algorithm_get_name</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fsrp_005fallocate_005fclient_005fcredentials-205"><code>gnutls_srp_allocate_client_credentials</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fsrp_005fallocate_005fserver_005fcredentials-206"><code>gnutls_srp_allocate_server_credentials</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fsrp_005fbase64_005fdecode-208"><code>gnutls_srp_base64_decode</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fsrp_005fbase64_005fdecode_005falloc-207"><code>gnutls_srp_base64_decode_alloc</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fsrp_005fbase64_005fencode-210"><code>gnutls_srp_base64_encode</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fsrp_005fbase64_005fencode_005falloc-209"><code>gnutls_srp_base64_encode_alloc</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fsrp_005ffree_005fclient_005fcredentials-211"><code>gnutls_srp_free_client_credentials</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fsrp_005ffree_005fserver_005fcredentials-212"><code>gnutls_srp_free_server_credentials</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fsrp_005fserver_005fget_005fusername-213"><code>gnutls_srp_server_get_username</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fsrp_005fset_005fclient_005fcredentials-215"><code>gnutls_srp_set_client_credentials</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fsrp_005fset_005fclient_005fcredentials_005ffunction-214"><code>gnutls_srp_set_client_credentials_function</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fsrp_005fset_005fserver_005fcredentials_005ffile-216"><code>gnutls_srp_set_server_credentials_file</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fsrp_005fset_005fserver_005fcredentials_005ffunction-217"><code>gnutls_srp_set_server_credentials_function</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fsrp_005fverifier-218"><code>gnutls_srp_verifier</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fstrerror-219"><code>gnutls_strerror</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005ftransport_005fget_005fptr-221"><code>gnutls_transport_get_ptr</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005ftransport_005fget_005fptr2-220"><code>gnutls_transport_get_ptr2</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005ftransport_005fset_005flowat-222"><code>gnutls_transport_set_lowat</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005ftransport_005fset_005fptr-224"><code>gnutls_transport_set_ptr</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005ftransport_005fset_005fptr2-223"><code>gnutls_transport_set_ptr2</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005ftransport_005fset_005fpull_005ffunction-225"><code>gnutls_transport_set_pull_function</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005ftransport_005fset_005fpush_005ffunction-226"><code>gnutls_transport_set_push_function</code></a>: <a href="#Core-functions">Core functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrl_005fcheck_005fissuer-264"><code>gnutls_x509_crl_check_issuer</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrl_005fdeinit-265"><code>gnutls_x509_crl_deinit</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrl_005fexport-266"><code>gnutls_x509_crl_export</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrl_005fget_005fcrt_005fcount-267"><code>gnutls_x509_crl_get_crt_count</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrl_005fget_005fcrt_005fserial-268"><code>gnutls_x509_crl_get_crt_serial</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrl_005fget_005fdn_005foid-269"><code>gnutls_x509_crl_get_dn_oid</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrl_005fget_005fissuer_005fdn-271"><code>gnutls_x509_crl_get_issuer_dn</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrl_005fget_005fissuer_005fdn_005fby_005foid-270"><code>gnutls_x509_crl_get_issuer_dn_by_oid</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrl_005fget_005fnext_005fupdate-272"><code>gnutls_x509_crl_get_next_update</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrl_005fget_005fsignature_005falgorithm-273"><code>gnutls_x509_crl_get_signature_algorithm</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrl_005fget_005fthis_005fupdate-274"><code>gnutls_x509_crl_get_this_update</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrl_005fget_005fversion-275"><code>gnutls_x509_crl_get_version</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrl_005fimport-276"><code>gnutls_x509_crl_import</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrl_005finit-277"><code>gnutls_x509_crl_init</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrl_005fset_005fcrt-279"><code>gnutls_x509_crl_set_crt</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrl_005fset_005fcrt_005fserial-278"><code>gnutls_x509_crl_set_crt_serial</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrl_005fset_005fnext_005fupdate-280"><code>gnutls_x509_crl_set_next_update</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrl_005fset_005fthis_005fupdate-281"><code>gnutls_x509_crl_set_this_update</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrl_005fset_005fversion-282"><code>gnutls_x509_crl_set_version</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrl_005fsign-284"><code>gnutls_x509_crl_sign</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrl_005fsign2-283"><code>gnutls_x509_crl_sign2</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrl_005fverify-285"><code>gnutls_x509_crl_verify</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrq_005fdeinit-286"><code>gnutls_x509_crq_deinit</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrq_005fexport-287"><code>gnutls_x509_crq_export</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrq_005fget_005fattribute_005fby_005foid-288"><code>gnutls_x509_crq_get_attribute_by_oid</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrq_005fget_005fchallenge_005fpassword-289"><code>gnutls_x509_crq_get_challenge_password</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrq_005fget_005fdn-292"><code>gnutls_x509_crq_get_dn</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrq_005fget_005fdn_005fby_005foid-290"><code>gnutls_x509_crq_get_dn_by_oid</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrq_005fget_005fdn_005foid-291"><code>gnutls_x509_crq_get_dn_oid</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrq_005fget_005fpk_005falgorithm-293"><code>gnutls_x509_crq_get_pk_algorithm</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrq_005fget_005fversion-294"><code>gnutls_x509_crq_get_version</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrq_005fimport-295"><code>gnutls_x509_crq_import</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrq_005finit-296"><code>gnutls_x509_crq_init</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrq_005fset_005fattribute_005fby_005foid-297"><code>gnutls_x509_crq_set_attribute_by_oid</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrq_005fset_005fchallenge_005fpassword-298"><code>gnutls_x509_crq_set_challenge_password</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrq_005fset_005fdn_005fby_005foid-299"><code>gnutls_x509_crq_set_dn_by_oid</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrq_005fset_005fkey-300"><code>gnutls_x509_crq_set_key</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrq_005fset_005fversion-301"><code>gnutls_x509_crq_set_version</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrq_005fsign-303"><code>gnutls_x509_crq_sign</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrq_005fsign2-302"><code>gnutls_x509_crq_sign2</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fcheck_005fhostname-304"><code>gnutls_x509_crt_check_hostname</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fcheck_005fissuer-305"><code>gnutls_x509_crt_check_issuer</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fcheck_005frevocation-306"><code>gnutls_x509_crt_check_revocation</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fcpy_005fcrl_005fdist_005fpoints-307"><code>gnutls_x509_crt_cpy_crl_dist_points</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fdeinit-308"><code>gnutls_x509_crt_deinit</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fexport-309"><code>gnutls_x509_crt_export</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fget_005factivation_005ftime-310"><code>gnutls_x509_crt_get_activation_time</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fget_005fauthority_005fkey_005fid-311"><code>gnutls_x509_crt_get_authority_key_id</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fget_005fca_005fstatus-312"><code>gnutls_x509_crt_get_ca_status</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fget_005fcrl_005fdist_005fpoints-313"><code>gnutls_x509_crt_get_crl_dist_points</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fget_005fdn-316"><code>gnutls_x509_crt_get_dn</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fget_005fdn_005fby_005foid-314"><code>gnutls_x509_crt_get_dn_by_oid</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fget_005fdn_005foid-315"><code>gnutls_x509_crt_get_dn_oid</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fget_005fexpiration_005ftime-317"><code>gnutls_x509_crt_get_expiration_time</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fget_005fextension_005fby_005foid-318"><code>gnutls_x509_crt_get_extension_by_oid</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fget_005fextension_005foid-319"><code>gnutls_x509_crt_get_extension_oid</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fget_005ffingerprint-320"><code>gnutls_x509_crt_get_fingerprint</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn-323"><code>gnutls_x509_crt_get_issuer_dn</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn_005fby_005foid-321"><code>gnutls_x509_crt_get_issuer_dn_by_oid</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fget_005fissuer_005fdn_005foid-322"><code>gnutls_x509_crt_get_issuer_dn_oid</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fget_005fkey_005fid-324"><code>gnutls_x509_crt_get_key_id</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fget_005fkey_005fpurpose_005foid-325"><code>gnutls_x509_crt_get_key_purpose_oid</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fget_005fkey_005fusage-326"><code>gnutls_x509_crt_get_key_usage</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fget_005fpk_005falgorithm-327"><code>gnutls_x509_crt_get_pk_algorithm</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fget_005fpk_005fdsa_005fraw-328"><code>gnutls_x509_crt_get_pk_dsa_raw</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fget_005fpk_005frsa_005fraw-329"><code>gnutls_x509_crt_get_pk_rsa_raw</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fget_005fserial-330"><code>gnutls_x509_crt_get_serial</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fget_005fsignature_005falgorithm-331"><code>gnutls_x509_crt_get_signature_algorithm</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fget_005fsubject_005falt_005fname-332"><code>gnutls_x509_crt_get_subject_alt_name</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fget_005fsubject_005fkey_005fid-333"><code>gnutls_x509_crt_get_subject_key_id</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fget_005fversion-334"><code>gnutls_x509_crt_get_version</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fimport-335"><code>gnutls_x509_crt_import</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005finit-336"><code>gnutls_x509_crt_init</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005flist_005fimport-337"><code>gnutls_x509_crt_list_import</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005flist_005fverify-338"><code>gnutls_x509_crt_list_verify</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fset_005factivation_005ftime-339"><code>gnutls_x509_crt_set_activation_time</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fset_005fauthority_005fkey_005fid-340"><code>gnutls_x509_crt_set_authority_key_id</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fset_005fca_005fstatus-341"><code>gnutls_x509_crt_set_ca_status</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fset_005fcrl_005fdist_005fpoints-342"><code>gnutls_x509_crt_set_crl_dist_points</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fset_005fcrq-343"><code>gnutls_x509_crt_set_crq</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fset_005fdn_005fby_005foid-344"><code>gnutls_x509_crt_set_dn_by_oid</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fset_005fexpiration_005ftime-345"><code>gnutls_x509_crt_set_expiration_time</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fset_005fextension_005fby_005foid-346"><code>gnutls_x509_crt_set_extension_by_oid</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fset_005fissuer_005fdn_005fby_005foid-347"><code>gnutls_x509_crt_set_issuer_dn_by_oid</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fset_005fkey-350"><code>gnutls_x509_crt_set_key</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fset_005fkey_005fpurpose_005foid-348"><code>gnutls_x509_crt_set_key_purpose_oid</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fset_005fkey_005fusage-349"><code>gnutls_x509_crt_set_key_usage</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fset_005fserial-351"><code>gnutls_x509_crt_set_serial</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fset_005fsubject_005falternative_005fname-352"><code>gnutls_x509_crt_set_subject_alternative_name</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fset_005fsubject_005fkey_005fid-353"><code>gnutls_x509_crt_set_subject_key_id</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fset_005fversion-354"><code>gnutls_x509_crt_set_version</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fsign-356"><code>gnutls_x509_crt_sign</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fsign2-355"><code>gnutls_x509_crt_sign2</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fto_005fxml-357"><code>gnutls_x509_crt_to_xml</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fverify-359"><code>gnutls_x509_crt_verify</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fcrt_005fverify_005fdata-358"><code>gnutls_x509_crt_verify_data</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fdn_005foid_005fknown-360"><code>gnutls_x509_dn_oid_known</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fprivkey_005fcpy-361"><code>gnutls_x509_privkey_cpy</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fprivkey_005fdeinit-362"><code>gnutls_x509_privkey_deinit</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fprivkey_005fexport-366"><code>gnutls_x509_privkey_export</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fprivkey_005fexport_005fdsa_005fraw-363"><code>gnutls_x509_privkey_export_dsa_raw</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fprivkey_005fexport_005fpkcs8-364"><code>gnutls_x509_privkey_export_pkcs8</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fprivkey_005fexport_005frsa_005fraw-365"><code>gnutls_x509_privkey_export_rsa_raw</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fprivkey_005ffix-367"><code>gnutls_x509_privkey_fix</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fprivkey_005fgenerate-368"><code>gnutls_x509_privkey_generate</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fprivkey_005fget_005fkey_005fid-369"><code>gnutls_x509_privkey_get_key_id</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fprivkey_005fget_005fpk_005falgorithm-370"><code>gnutls_x509_privkey_get_pk_algorithm</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fprivkey_005fimport-374"><code>gnutls_x509_privkey_import</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fprivkey_005fimport_005fdsa_005fraw-371"><code>gnutls_x509_privkey_import_dsa_raw</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fprivkey_005fimport_005fpkcs8-372"><code>gnutls_x509_privkey_import_pkcs8</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fprivkey_005fimport_005frsa_005fraw-373"><code>gnutls_x509_privkey_import_rsa_raw</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fprivkey_005finit-375"><code>gnutls_x509_privkey_init</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fprivkey_005fsign_005fdata-376"><code>gnutls_x509_privkey_sign_data</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005fprivkey_005fverify_005fdata-377"><code>gnutls_x509_privkey_verify_data</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005frdn_005fget-380"><code>gnutls_x509_rdn_get</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005frdn_005fget_005fby_005foid-378"><code>gnutls_x509_rdn_get_by_oid</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
<li><a href="#index-gnutls_005fx509_005frdn_005fget_005foid-379"><code>gnutls_x509_rdn_get_oid</code></a>: <a href="#X_002e509-certificate-functions">X.509 certificate functions</a></li>
</ul><!-- texi2dvi has problem if unnumbered is put there. However makeinfo works great. -->
<!-- STUPID texinfo. -->
<!-- @node @mybibnode{} -->
<!-- @unnumbered @mybibnode{} -->
<div class="node">
<p><hr>
<a name="Bibliography"></a>
Previous: <a rel="previous" accesskey="p" href="#Function-and-Data-Index">Function and Data Index</a>,
Up: <a rel="up" accesskey="u" href="#Top">Top</a>
</div>
<h2 class="unnumbered">Bibliography</h2>
<dl>
<!-- %**else if -->
<dt><a name="CBCATT"></a>[CBCATT]<dd>
Bodo Moeller, "Security of CBC Ciphersuites in SSL/TLS: Problems and Countermeasures",
2002, Available from <a href="http://www.openssl.org/~bodo/tls-cbc.txt">http://www.openssl.org/~bodo/tls-cbc.txt</a>.
<!-- %**else if -->
<br><dt><a name="GPGH"></a>[GPGH]<dd>
Mike Ashley, "The GNU Privacy Handbook", 2002,
Available from <a href="http://www.gnupg.org/gph/en/manual.pdf">http://www.gnupg.org/gph/en/manual.pdf</a>.
<!-- %**else if -->
<br><dt><a name="GUTPKI"></a>[GUTPKI]<dd>
Peter Gutmann, "Everything you never wanted to know about PKI but were forced to find out",
Available from <a href="http://www.cs.auckland.ac.nz/~pgut001/">http://www.cs.auckland.ac.nz/~pgut001/</a>.
<!-- %**else if -->
<br><dt><a name="RFC2246"></a>[RFC2246]<dd>
Tim Dierks and Christopher Allen, "The TLS Protocol Version 1.0",
January 1999, Available from <a href="http://kaizi.viagenie.qc.ca/ietf/rfc/rfc2246.txt">http://kaizi.viagenie.qc.ca/ietf/rfc/rfc2246.txt</a>.
<!-- %**else if -->
<br><dt><a name="RFC4346"></a>[RFC4346]<dd>
Tim Dierks and Eric Rescorla, "The TLS Protocol Version 1.1",
Match 2006, Available from <a href="http://kaizi.viagenie.qc.ca/ietf/rfc/rfc4346.txt">http://kaizi.viagenie.qc.ca/ietf/rfc/rfc4346.txt</a>.
<!-- %**else if -->
<br><dt><a name="RFC2440"></a>[RFC2440]<dd>
Jon Callas, Lutz Donnerhacke, Hal Finney and Rodney Thayer,
"OpenPGP Message Format", November 1998, Available from <a href="http://kaizi.viagenie.qc.ca/ietf/rfc/rfc2440.txt">http://kaizi.viagenie.qc.ca/ietf/rfc/rfc2440.txt</a>.
<!-- %**else if -->
<br><dt><a name="RFC2511"></a>[RFC2511]<dd>
Michael Myers, Carlisle Adams, Dave Solo and David Kemp,
"Internet X.509 Certificate Request Message Format", March 1999, Available from <a href="http://kaizi.viagenie.qc.ca/ietf/rfc/rfc2511.txt">http://kaizi.viagenie.qc.ca/ietf/rfc/rfc2511.txt</a>.
<!-- %**else if -->
<br><dt><a name="RFC2817"></a>[RFC2817]<dd>
Rohit Khare and Scott Lawrence, "Upgrading to TLS Within HTTP/1.1",
May 2000, Available from <a href="http://kaizi.viagenie.qc.ca/ietf/rfc/rfc2817.txt">http://kaizi.viagenie.qc.ca/ietf/rfc/rfc2817.txt</a>
<!-- %**else if -->
<br><dt><a name="RFC2818"></a>[RFC2818]<dd>
Eric Rescola, "HTTP Over TLS", May 2000,
Available from <a href="http://kaizi.viagenie.qc.ca/ietf/rfc/rfc2818.txt">http://kaizi.viagenie.qc.ca/ietf/rfc/rfc2818.txt</a>.
<!-- %**else if -->
<br><dt><a name="RFC2945"></a>[RFC2945]<dd>
Tom Wu, "The SRP Authentication and Key Exchange System",
September 2000, Available from <a href="http://kaizi.viagenie.qc.ca/ietf/rfc/rfc2945.txt">http://kaizi.viagenie.qc.ca/ietf/rfc/rfc2945.txt</a>.
<!-- %**else if -->
<br><dt><a name="RFC2986"></a>[RFC2986]<dd>
Magnus Nystrom and Burt Kaliski, "PKCS 10 v1.7: Certification Request Syntax Specification",
November 2000, Available from <a href="http://kaizi.viagenie.qc.ca/ietf/rfc/rfc2986.txt">http://kaizi.viagenie.qc.ca/ietf/rfc/rfc2986.txt</a>.
<!-- %**else if -->
<br><dt><a name="RFC3280"></a>[RFC3280]<dd>
Russell Housley, Tim Polk, Warwick Ford and David Solo,
"Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile",
April 2002, Available from <a href="http://kaizi.viagenie.qc.ca/ietf/rfc/rfc3280.txt">http://kaizi.viagenie.qc.ca/ietf/rfc/rfc3280.txt</a>.
<!-- %**else if -->
<br><dt><a name="RFC3749"></a>[RFC3749]<dd>
Scott Hollenbeck, "Transport Layer Security Protocol Compression Methods",
May 2004, Available from <a href="http://kaizi.viagenie.qc.ca/ietf/rfc/rfc3749.txt">http://kaizi.viagenie.qc.ca/ietf/rfc/rfc3749.txt</a>.
<!-- %**else if -->
<br><dt><a name="PKCS12"></a>[PKCS12]<dd>
RSA Laboratories, "PKCS 12 v1.0: Personal Information Exchange Syntax",
June 1999, Available from <a href="http://www.rsa.com">http://www.rsa.com</a>.
<!-- %**else if -->
<br><dt><a name="RESCOLA"></a>[RESCOLA]<dd>
Eric Rescola, "SSL and TLS: Designing and Building Secure Systems", 2001
<!-- %**else if -->
<br><dt><a name="SSL3"></a>[SSL3]<dd>
Alan Freier, Philip Karlton and Paul Kocher, "The SSL Protocol Version 3.0",
November 1996, Available from <a href="http://wp.netscape.com/eng/ssl3/draft302.txt">http://wp.netscape.com/eng/ssl3/draft302.txt</a>.
<!-- %**else if -->
<br><dt><a name="STEVENS"></a>[STEVENS]<dd>
Richard Stevens, "UNIX Network Programming, Volume 1", Prentice Hall PTR,
January 1998
<!-- %**else if -->
<br><dt><a name="TLSEXT"></a>[TLSEXT]<dd>
Simon Blake-Wilson, Magnus Nystrom, David Hopwood, Jan Mikkelsen and Tim Wright,
"Transport Layer Security (TLS) Extensions", June 2003,
Available from <a href="http://kaizi.viagenie.qc.ca/ietf/rfc/rfc3546.txt">http://kaizi.viagenie.qc.ca/ietf/rfc/rfc3546.txt</a>.
<!-- %**else if -->
<br><dt><a name="TLSPGP"></a>[TLSPGP]<dd>
Nikos Mavrogiannopoulos, "Using OpenPGP keys for TLS authentication",
April 2004, Internet draft, work in progress. Available from <a href="http://www.normos.org/ietf/draft/draft-ietf-tls-openpgp-keys-05.txt">http://www.normos.org/ietf/draft/draft-ietf-tls-openpgp-keys-05.txt</a>.
<!-- %**else if -->
<br><dt><a name="TLSSRP"></a>[TLSSRP]<dd>
David Taylor, Trevor Perrin, Tom Wu and Nikos Mavrogiannopoulos,
"Using SRP for TLS Authentication", August 2005,
Internet draft, work in progress. Available from <a href="http://www.normos.org/ietf/draft/draft-ietf-tls-srp-08.txt">http://www.normos.org/ietf/draft/draft-ietf-tls-srp-08.txt</a>.
<!-- %**else if -->
<br><dt><a name="TLSPSK"></a>[TLSPSK]<dd>
Pasi Eronen and Hannes Tschofenig,
"Pre-shared key Ciphersuites for TLS", December 2005,
Available from <a href="http://kaizi.viagenie.qc.ca/ietf/rfc/rfc4279.txt">http://kaizi.viagenie.qc.ca/ietf/rfc/rfc4279.txt</a>.
<!-- %**else if -->
<br><dt><a name="TOMSRP"></a>[TOMSRP]<dd>
Tom Wu, "The Stanford SRP Authentication Project",
Available at <a href="http://srp.stanford.edu/">http://srp.stanford.edu/</a>.
<!-- %**else if -->
<br><dt><a name="WEGER"></a>[WEGER]<dd>
Arjen Lenstra and Xiaoyun Wang and Benne de Weger, "Colliding X.509 Certificates",
Cryptology ePrint Archive, Report 2005/067,
Available at <a href="http://eprint.iacr.org/">http://eprint.iacr.org/</a>.
</dl>
<div class="footnote">
<hr>
<a name="texinfo-footnotes-in-document"></a><h4>Footnotes</h4><p class="footnote"><small>[<a name="fn-1" href="#fnd-1">1</a>]</small> A copy of the license is included in the
distribution</p>
<p class="footnote"><small>[<a name="fn-2" href="#fnd-2">2</a>]</small> <a href="http://www.openssl.org/">http://www.openssl.org/</a></p>
<p class="footnote"><small>[<a name="fn-3" href="#fnd-3">3</a>]</small> <a href="ftp://ftp.gnupg.org/gcrypt/alpha/gnutls/libtasn1/">ftp://ftp.gnupg.org/gcrypt/alpha/gnutls/libtasn1/</a></p>
<p class="footnote"><small>[<a name="fn-4" href="#fnd-4">4</a>]</small> <a href="ftp://ftp.gnupg.org/gcrypt/alpha/gnutls/opencdk/">ftp://ftp.gnupg.org/gcrypt/alpha/gnutls/opencdk/</a></p>
<p class="footnote"><small>[<a name="fn-5" href="#fnd-5">5</a>]</small> <a href="ftp://ftp.gnupg.org/gcrypt/alpha/libgcrypt/">ftp://ftp.gnupg.org/gcrypt/alpha/libgcrypt/</a></p>
<p class="footnote"><small>[<a name="fn-6" href="#fnd-6">6</a>]</small> The first message in a <acronym>TLS</acronym> handshake</p>
<p class="footnote"><small>[<a name="fn-7" href="#fnd-7">7</a>]</small> 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>
<p class="footnote"><small>[<a name="fn-8" href="#fnd-8">8</a>]</small> AES,
or Advanced Encryption Standard, is actually the RIJNDAEL algorithm.
This is the algorithm that replaced DES.</p>
<p class="footnote"><small>[<a name="fn-9" href="#fnd-9">9</a>]</small> <code>ARCFOUR_128</code> is a compatible
algorithm with RSA's RC4 algorithm, which is considered to be a trade
secret.</p>
<p class="footnote"><small>[<a name="fn-10" href="#fnd-10">10</a>]</small> You should use
<a href="#gnutls_005fhandshake_005fset_005fprivate_005fextensions">gnutls_handshake_set_private_extensions</a> to enable private
extensions.</p>
<p class="footnote"><small>[<a name="fn-11" href="#fnd-11">11</a>]</small> MAC stands for Message Authentication Code. It can be described as a keyed hash algorithm. See RFC2104.</p>
<p class="footnote"><small>[<a name="fn-12" href="#fnd-12">12</a>]</small> It really depends on the group used. Primes with
lesser bits are always faster, but also easier to break. Values less
than 768 should not be used today</p>
<p class="footnote"><small>[<a name="fn-13" href="#fnd-13">13</a>]</small> <acronym>SRP</acronym> is described in <!-- %**else if -->
[RFC2945] (See <a href="#Bibliography">RFC2945</a>.)
</p>
<p class="footnote"><small>[<a name="fn-14" href="#fnd-14">14</a>]</small> See also the Server Name Indication extension on
<a href="#serverind">serverind</a>.</p>
<p class="footnote"><small>[<a name="fn-15" href="#fnd-15">15</a>]</small> See LDAP, IMAP etc.</p>
<p class="footnote"><small>[<a name="fn-16" href="#fnd-16">16</a>]</small> in <acronym>SRP</acronym> authentication</p>
<p class="footnote"><small>[<a name="fn-17" href="#fnd-17">17</a>]</small> such as the <code>gnutls_certificate_credentials_t</code> structures</p>
<p><hr></div>
</body></html>
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