You have to set up Enigma plugin :
cp /……../roundcubemail/plugins/enigma/config.inc.php.dist /……../roundcubemail/plugins/enigma/config.inc.php
<?php
// Enigma Plugin options
// --------------------
// A driver to use for PGP. Default: "gnupg".
$config['enigma_pgp_driver'] = 'gnupg';
// A driver to use for S/MIME. Default: "phpssl".
$config['enigma_smime_driver'] = 'phpssl';
// Enables logging of enigma operations (including Crypt_GPG debug info)
$config['enigma_debug'] = true;
// Keys directory for all users. Default 'enigma/home'.
// Must be writeable by PHP process
$config['enigma_pgp_homedir'] = enigma/home;
// Location of gpg binary. By default it will be auto-detected.
// This is also a way to force gpg2 use if there are both 1.x and 2.x on the system.
$config['enigma_pgp_binary'] = '/usr/bin/gpg';
// Location of gpg-agent binary. By default it will be auto-detected.
// It's used with GnuPG 2.x.
$config['enigma_pgp_agent'] = '';
// Location of gpgconf binary. By default it will be auto-detected.
// It's used with GnuPG >= 2.1.
$config['enigma_pgp_gpgconf'] = '';
// Enables signatures verification feature.
$config['enigma_signatures'] = true;
// Enables messages decryption feature.
$config['enigma_decryption'] = true;
// Enables messages encryption and signing feature.
$config['enigma_encryption'] = true;
// Enable signing all messages by default
$config['enigma_sign_all'] = false;
// Enable encrypting all messages by default
$config['enigma_encrypt_all'] = false;
// Enable attaching a public key to all messages by default
$config['enigma_attach_pubkey'] = false;
// Default for how long to store private key passwords (in minutes).
// When set to 0 passwords will be stored for the whole session.
$config['enigma_password_time'] = 0;
// With this option you can lock composing options
// of the plugin forcing the user to use configured settings.
// The array accepts: 'sign', 'encrypt', 'pubkey'.
//
// For example, to force your users to sign every email,
// you should set:
// - enigma_sign_all = true
// - enigma_options_lock = array('sign')
// - dont_override = array('enigma_sign_all')
$config['enigma_options_lock'] = array();
Installation and settings Enigma plugin
Preferences > Settings > Encryption you’ll have the possibility to enable/disable encryption-related features.
The keys are stored on the server.
Figure 1. Encryption preferences section.
Goto Settings > PGP Keys. There you can generate a new key pair or import keys.
Figure 2. Key generation form.
Figure 3. Key information frame.
Composing messages
Figure 4. Encryption options in compose.
