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EasyPG Assistant user's manual
******************************

EasyPG Assistant is an Emacs user interface to GNU Privacy Guard (GnuPG, see Using the GNU Privacy Guard).

EasyPG Assistant is a part of the package called EasyPG, an all-in-one GnuPG interface for Emacs.  EasyPG also contains the library interface called EasyPG Library.

This file describes EasyPG Assistant 1.0.0.

Copyright © 2007--2020 Free Software Foundation, Inc.

     Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, with the Front-Cover Texts being ``A GNU Manual,'' and with the Back-Cover Texts as in (a) below.  A copy of the license is included in the section entitled ``GNU Free Documentation License''.

     (a) The FSF's Back-Cover Text is: ``You have the freedom to copy and modify this GNU manual.''

Overview
********

EasyPG Assistant provides the following features.

  * Key management.

  * Cryptographic operations on regions.

  * Cryptographic operations on files.

  * Dired integration.

  * Mail-mode integration.

  * Automatic encryption/decryption of *.gpg files.

Quick start
***********

EasyPG Assistant commands are prefixed by epa-.  For example,

  * To browse your keyring, type M-x epa-list-keys

  * To create a cleartext signature of the region, type M-x epa-sign-region

  * To encrypt a file, type M-x epa-encrypt-file

EasyPG Assistant provides several cryptographic features which can be integrated into other Emacs functionalities.  For example, automatic encryption/decryption of *.gpg files.

Commands
********

This chapter introduces various commands for typical use cases.

Key management
==============

Probably the first step of using EasyPG Assistant is to browse your keyring.  M-x epa-list-keys is corresponding to gpg --list-keys from the command line.

 -- Command: epa-list-keys name mode
     Show all keys matched with NAME from the public keyring.

The output looks as follows.

       u A5B6B2D4B15813FE Daiki Ueno <ueno@unixuser.org>

A character on the leftmost column indicates the trust level of the key.  If it is u, the key is marked as ultimately trusted.  The second column is the key ID, and the rest is the user ID.

You can move over entries by TAB.  If you type RET or click button1 on an entry, you will see more detailed information about the key you selected.

      u Daiki Ueno <ueno@unixuser.org>
      u A5B6B2D4B15813FE 1024bits DSA
             Created: 2001-10-09
             Expires: 2007-09-04
             Capabilities: sign certify
             Fingerprint: 8003 7CD0 0F1A 9400 03CA  50AA A5B6 B2D4 B158 13FE
      u 4447461B2A9BEA2D 2048bits ELGAMAL_E
             Created: 2001-10-09
             Expires: 2007-09-04
             Capabilities: encrypt
             Fingerprint: 9003 D76B 73B7 4A8A E588  10AF 4447 461B 2A9B EA2D

To browse your private keyring, use M-x epa-list-secret-keys.

 -- Command: epa-list-secret-keys name
     Show all keys matched with NAME from the private keyring.

In *Keys* buffer, several commands are available.  The common use case is to export some keys to a file.  To do that, type m to select keys, type o, and then supply the filename.

Below are other commands related to key management.  Some of them take a file as input/output, and others take the current region.

 -- Command: epa-insert-keys keys
     Insert selected KEYS after the point.  It will let you select keys before insertion.  By default, it will encode keys in the OpenPGP armor format.

 -- Command: epa-import-keys file
     Import keys from FILE to your keyring.

 -- Command: epa-import-keys-region start end
     Import keys from the current region between START and END to your keyring.

 -- Command: epa-import-armor-in-region start end
     Import keys in the OpenPGP armor format in the current region between START and END.  The difference from epa-import-keys-region is that epa-import-armor-in-region searches armors in the region and applies epa-import-keys-region to each of them.

 -- Command: epa-delete-keys allow-secret
     Delete selected keys.  If ALLOW-SECRET is non-nil, it also delete the secret keys.

Cryptographic operations on regions
===================================

 -- Command: epa-decrypt-region start end
     Decrypt the current region between START and END.  It replaces the region with the decrypted text.

 -- Command: epa-decrypt-armor-in-region start end
     Decrypt OpenPGP armors in the current region between START and END.  The difference from epa-decrypt-region is that epa-decrypt-armor-in-region searches armors in the region and applies epa-decrypt-region to each of them.  That is, this command does not alter the original text around armors.

 -- Command: epa-verify-region start end
     Verify the current region between START and END.  It sends the verification result to the minibuffer or a popup window.  It replaces the region with the signed text.

 -- Command: epa-verify-cleartext-in-region
     Verify OpenPGP cleartext blocks in the current region between START and END.  The difference from epa-verify-region is that epa-verify-cleartext-in-region searches OpenPGP cleartext blocks in the region and applies epa-verify-region to each of them.  That is, this command does not alter the original text around OpenPGP cleartext blocks.

 -- Command: epa-sign-region start end signers type
     Sign the current region between START and END.  By default, it creates a cleartext signature.  If a prefix argument is given, it will let you select signing keys, and then a signature type.

 -- Command: epa-encrypt-region start end recipients sign signers
     Encrypt the current region between START and END.  It will let you select recipients.  If a prefix argument is given, it will also ask you whether or not to sign the text before encryption and if you answered yes, it will let you select the signing keys.

Cryptographic operations on files
=================================

 -- Command: epa-decrypt-file file &optional output
     Decrypt FILE.  If you do not specify the name OUTPUT to use for the decrypted file, this function prompts for the value to use.

 -- Command: epa-verify-file file
     Verify FILE.

 -- Command: epa-sign-file file signers type
     Sign FILE.  If a prefix argument is given, it will let you select signing keys, and then a signature type.

 -- Command: epa-encrypt-file file recipients
     Encrypt FILE.  It will let you select recipients.

Dired integration
=================

EasyPG Assistant extends Dired Mode for GNU Emacs to allow users to easily do cryptographic operations on files.  For example,

     M-x dired
     (mark some files)
     : e (or M-x epa-dired-do-encrypt)
     (select recipients by 'm' and click [OK])

The following keys are assigned.

: d
     Decrypt marked files.

: v
     Verify marked files.

: s
     Sign marked files.

: e
     Encrypt marked files.

Mail-mode integration
=====================

EasyPG Assistant provides a minor mode epa-mail-mode to help user compose inline OpenPGP messages.  Inline OpenPGP is a traditional style of sending signed/encrypted emails by embedding raw OpenPGP blobs inside a message body, not using modern MIME format.

NOTE: Inline OpenPGP is not recommended and you should consider to use PGP/MIME.  See Inline OpenPGP in E-mail is bad, Mm'kay? (https://josefsson.org/inline-openpgp-considered-harmful.html).

Once epa-mail-mode is enabled, the following keys are assigned. You can do it by C-u 1 M-x epa-mail-mode or through the Customize interface.  Try M-x customize-variable epa-global-mail-mode.

C-c C-e C-d and C-c C-e d
     Decrypt OpenPGP armors in the current buffer.

C-c C-e C-v and C-c C-e v
     Verify OpenPGP cleartext signed messages in the current buffer.

C-c C-e C-s and C-c C-e s
     Compose a signed message from the current buffer, using your default key.  With a prefix argument, select the key to use interactively.

C-c C-e C-e and C-c C-e e
     Compose an encrypted message from the current buffer. By default it tries to build the recipient list from to, cc, and bcc fields of the mail header.  To include your key in the recipient list, use encrypt-to option in ~/.gnupg/gpg.conf.  This function translates recipient addresses using the epa-mail-aliases list.  You can also use that option to ignore specific recipients for encryption purposes.

     With prefix argument, asks you to select the recipients interactively, whether to sign, and which key(s) to sign with.

Encrypting/decrypting gpg files
===============================

By default, every file whose name ends with .gpg will be treated as encrypted.  That is, when you open such a file, the decrypted text is inserted in the buffer rather than encrypted one. Similarly, when you save the buffer to a foo.gpg file, encrypted data is written.

The file name pattern for encrypted files can be controlled by epa-file-name-regexp.

 -- Variable: epa-file-name-regexp
     Regexp which matches filenames treated as encrypted.

You can disable this behavior with M-x epa-file-disable, and then get it back with M-x epa-file-enable.

 -- Command: epa-file-disable
     Disable automatic encryption/decryption of *.gpg files.

 -- Command: epa-file-enable
     Enable automatic encryption/decryption of *.gpg files.

By default, epa-file will try to use symmetric encryption, aka password-based encryption.  If you want to use public key encryption instead, do M-x epa-file-select-keys, which pops up the key selection dialog.

 -- Command: epa-file-select-keys
     Select recipient keys to encrypt the currently visiting file with public key encryption.

You can also change the default behavior with the variable epa-file-select-keys.

 -- Variable: epa-file-select-keys
     Control whether or not to pop up the key selection dialog.

For frequently visited files, it might be a good idea to tell Emacs which encryption method should be used through see File Variables (the Emacs Manual).  Use the epa-file-encrypt-to local variable for this.

For example, if you want an Elisp file to be encrypted with a public key associated with an email address ueno@unixuser.org, add the following line to the beginning of the file.

     ;; -*- epa-file-encrypt-to: ("ueno@unixuser.org") -*-

Instead, if you want the file always (regardless of the value of the epa-file-select-keys variable) encrypted with symmetric encryption, change the line as follows.

     ;; -*- epa-file-encrypt-to: nil -*-

Other variables which control the automatic encryption/decryption behavior are below.

 -- Variable: epa-file-cache-passphrase-for-symmetric-encryption
     If non-nil, cache passphrase for symmetric encryption.  The default value is nil.

 -- Variable: epa-file-inhibit-auto-save
     If non-nil, disable auto-saving when opening an encrypted file. The default value is t.

GnuPG version compatibility
***************************

As of February 2016, there are three active branches of GnuPG: 2.1, 2.0, and 1.4.  All those branches should work flawlessly with Emacs with basic use-cases.  They have, however, some incompatible characteristics, which might be visible when used from Emacs.

  * The key store format used by GnuPG 2.1 is incompatible with 1.4.  That means, a key created with GnuPG 2.1 is not visible with 1.4.

  * GnuPG 2.1 uses a fixed address for the Unix domain socket used to communicate with gpg-agent.  The GPG_AGENT_INFO environment variable, which is used by GnuPG 2.0 and 1.4, is ignored.  That means, if your system has both GnuPG 2.1 and 1.4, the gpg command from GnuPG 1.4 is not able to use gpg-agent provided by 2.1 (at least out of box).

  * GnuPG 2.1 (2.1.5 or later) has a mechanism to direct the Pinentry password prompt to the Emacs minibuffer (To enable this feature, add allow-emacs-pinentry to ~/.gnupg/gpg-agent.conf and let gpg-agent reload the configuration, with: gpgconf --reload gpg-agent), which would be useful when you use Emacs remotely or from a text-only terminal. That feature is not available in other versions, and more specifically, with 2.0 (as of 2.0.29), there is no way to avoid the graphical prompt.

Caching Passphrases
*******************

Typing passphrases is a troublesome task if you frequently open and close the same file.  GnuPG and EasyPG Assistant provide mechanisms to remember your passphrases for a limited time.  Using these, you only need to re-enter the passphrase occasionally. However, the configuration is a bit confusing since it depends on your GnuPG installationsee GnuPG version compatibility, encryption method (symmetric or public key), and whether or not you want to use gpg-agent.  Here are some questions:

 1. Do you use GnuPG version 2.1 or 2.0 instead of GnuPG version 1.4?

 2. Do you use symmetric encryption rather than public key encryption?

 3. Do you want to use gpg-agent?

Here are configurations depending on your answers:

1   2   3   Configuration
Yes   Yes   Yes   Set up gpg-agent.
Yes   Yes   No   You can't, without gpg-agent.
Yes   No   Yes   Set up gpg-agent.
Yes   No   No   You can't, without gpg-agent.
No   Yes   Yes   Set up elisp passphrase cache.
No   Yes   No   Set up elisp passphrase cache.
No   No   Yes   Set up gpg-agent.
No   No   No   You can't, without gpg-agent.

To set up gpg-agent, follow the instruction in GnuPG manual. see Invoking GPG-AGENT (gnupg).

To set up elisp passphrase cache, set epa-file-cache-passphrase-for-symmetric-encryption. See Encrypting/decrypting gpg files.

Bug Reports
***********

Bugs and problems with EasyPG Assistant are actively worked on by the Emacs development team.  Feature requests and suggestions are also more than welcome.  Use M-x report-emacs-bug, see Bugs (Reporting Bugs).

When submitting a bug report, please try to describe in excruciating detail the steps required to reproduce the problem.  Also try to collect necessary information to fix the bug, such as:

  * the GnuPG version.  Send the output of gpg --version.

  * the GnuPG configuration.  Send the contents of ~/.gnupg/gpg.conf.

Before reporting the bug, you should set epg-debug in the ~/.emacs file and repeat the bug.  Then, include the contents of the  *epg-debug* buffer.  Note that the first letter of the buffer name is a whitespace.

GNU Free Documentation License
******************************

     [file doclicense.texi not included]