/**
* Encrypt data.
*
* @param string $text Plaintext.
*
* @return array Array of MPI values (c1, c2).
*/
public function encrypt($text)
{
$p_len = strlen($this->_key->key['p']);
$length = $p_len - 11;
if ($length <= 0) {
return false;
}
$g = new BigInteger($this->_key->key['g'], 256);
$p = new BigInteger($this->_key->key['p'], 256);
$y = new BigInteger($this->_key->key['y'], 256);
$out = array();
foreach (str_split($text, $length) as $m) {
// EME-PKCS1-v1_5 encoding
$psLen = $p_len - strlen($m) - 3;
$ps = '';
while (($psLen2 = strlen($ps)) != $psLen) {
$tmp = Random::String($psLen - $psLen2);
$ps .= str_replace("", '', $tmp);
}
$em = new BigInteger(chr(0) . chr(2) . $ps . chr(0) . $m, 256);
// End EME-PKCS1-v1_5 encoding
$k = Horde_Pgp_Crypt_DSA::randomNumber($p);
$c1 = $g->modPow($k, $p);
$c2_base = $y->modPow($k, $p)->multiply($em)->divide($p);
$c2 = $c2_base[1];
$out[] = str_pad($c1->toBytes(), $p_len, chr(0), STR_PAD_LEFT);
$out[] = str_pad($c2->toBytes(), $p_len, chr(0), STR_PAD_LEFT);
}
return $out;
}
/**
* Generate a number that lies between 0 and q-1.
*
* @param \phpseclib\Math\BigInteger $q Max number.
*
* @return \phpseclib\Math\BigInteger Generated number.
*/
public static function randomNumber($q)
{
$bytes = strlen($q->toBytes()) + 8;
$ints = $bytes + 1 >> 2;
$cstring = Crypt\Random::String($ints);
$random = '';
for ($i = 0; $i < $ints; ++$i) {
$random .= pack('N', $cstring[$i]);
}
$c = new BigInteger(substr($random, 0, $bytes), 256);
$one = new BigInteger(1);
$result_base = $c->divide($q->subtract($one));
return $result_base[1]->add($one);
}
/**
* 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)));
}
