OpenPGP_Crypt_Symmetric::getCipher PHP Method

    public static function getCipher($algo)
    {
        $cipher = NULL;
        switch ($algo) {
            case 2:
                $cipher = new Crypt_TripleDES(CRYPT_DES_MODE_CFB);
                $key_bytes = 24;
                $key_block_bytes = 8;
                break;
            case 3:
                /* Horde change
                   if(defined('MCRYPT_CAST_128')) {
                     $cipher = new MCryptWrapper(MCRYPT_CAST_128);
                   }
                   */
                $cipher = new Horde_Pgp_Crypt_Cast128();
                /* End Horde Change */
                break;
                /* Horde change */
            /* Horde change */
            case 4:
                $cipher = new Crypt_Blowfish(CRYPT_BLOWFISH_MODE_CFB);
                $key_bytes = 16;
                break;
                /* End Horde Change */
            /* End Horde Change */
            case 7:
                $cipher = new Crypt_AES(CRYPT_AES_MODE_CFB);
                $cipher->setKeyLength(128);
                break;
            case 8:
                $cipher = new Crypt_AES(CRYPT_AES_MODE_CFB);
                $cipher->setKeyLength(192);
                break;
            case 9:
                $cipher = new Crypt_AES(CRYPT_AES_MODE_CFB);
                $cipher->setKeyLength(256);
                break;
                /* Horde change */
            /* Horde change */
            case 10:
                $cipher = new Crypt_Twofish(CRYPT_TWOFISH_MODE_CFB);
                $key_bytes = 32;
                break;
                /* End Horde Change */
        }
        if (!$cipher) {
            return array(NULL, NULL, NULL);
        }
        // Unsupported cipher
        if (!isset($key_bytes)) {
            $key_bytes = isset($cipher->key_size) ? $cipher->key_size : $cipher->key_length;
        }
        if (!isset($key_block_bytes)) {
            $key_block_bytes = $cipher->block_size;
        }
        return array($cipher, $key_bytes, $key_block_bytes);
    }

 /**
  * Encrypt data.
  *
  * @param mixed $key   The list of public keys used to encrypt or a list
  *                     of passphrases.
  * @param mixed $data  The data to be PGP encrypted.
  * @param array $opts  Additional options:
  *   - cipher: (integer) Cipher algorithm.
  *   - compress: (integer) Compression algorithm.
  *
  * @param Horde_Pgp_Element_Message  Encrypted message.
  */
 protected function _encrypt($key, $data, $opts)
 {
     $msg = $this->_compressMessageOb($this->_getMessageOb($data), $opts['compress']);
     /* Following code adapted from OpenPGP_Crypt_Symmetric::encrypt(). */
     list($cipher, $key_bytes, $block_bytes) = OpenPGP_Crypt_Symmetric::getCipher($opts['cipher']);
     $prefix = crypt_random_string($block_bytes);
     $prefix .= substr($prefix, -2);
     $to_encrypt = $prefix . $msg->to_bytes();
     $mdc = new OpenPGP_ModificationDetectionCodePacket(hash('sha1', $to_encrypt . "Ó", true));
     /* This is the symmetric encryption session key. */
     $ckey = crypt_random_string($key_bytes);
     $cipher->setKey($ckey);
     /* This is the symmetrically encrypted version of plaintext. */
     $encrypted = array(new OpenPGP_IntegrityProtectedDataPacket($cipher->encrypt($to_encrypt . $mdc->to_bytes())));
     /* Now we need to encrypt the symmetric session key into the various
      * session key encrypted entities. */
     foreach ($key as $k) {
         /* Symmetric encryption. */
         if (is_string($k)) {
             $s2k = new OpenPGP_S2K(crypt_random_string(8, 2));
             // SHA-1
             $cipher->setKey($s2k->make_key($k, $key_bytes));
             $encrypted[] = new OpenPGP_SymmetricSessionKeyPacket($s2k, $cipher->encrypt(chr($opts['cipher']) . $ckey), $opts['cipher']);
             continue;
         }
         /* Public key encryption. */
         switch ($k->algorithm) {
             case 1:
             case 2:
             case 3:
                 $rsa = new OpenPGP_Crypt_RSA($k);
                 $pk = $rsa->public_key();
                 $pk->setEncryptionMode(CRYPT_RSA_ENCRYPTION_PKCS1);
                 break;
             case 16:
                 $pk = new Horde_Pgp_Crypt_Elgamal($k);
                 break;
         }
         $pk_encrypt = $pk->encrypt(chr($opts['cipher']) . $ckey . pack('n', OpenPGP_Crypt_Symmetric::checksum($ckey)));
         $esk = array();
         foreach (is_array($pk_encrypt) ? $pk_encrypt : array($pk_encrypt) as $val) {
             $esk[] = pack('n', OpenPGP::bitlength($val)) . $val;
         }
         $encrypted[] = new OpenPGP_AsymmetricSessionKeyPacket($k->algorithm, $k->fingerprint(), implode('', $esk));
     }
     return new Horde_Pgp_Element_Message(new OpenPGP_Message(array_reverse($encrypted)));
 }