Generate a number that lies between 0 and q-1.
| public static randomNumber ( phpseclib\Math\BigInteger $q ) : phpseclib\Math\BigInteger | ||
| $q | phpseclib\Math\BigInteger | Max number. |
| return | phpseclib\Math\BigInteger | Generated number. |
/**
* 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;
}
$g = new Math_BigInteger($this->_key->key['g'], 256);
$p = new Math_BigInteger($this->_key->key['p'], 256);
$y = new Math_BigInteger($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) {
$tmp = crypt_random_string($psLen - $psLen2);
$ps .= str_replace("", '', $tmp);
}
$em = new Math_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;
}
