| public static decryptPacket ( $epacket, $symmetric_algorithm, $key ) |
function decrypt($packet)
{
if (!is_object($packet)) {
$packet = OpenPGP_Message::parse($packet);
}
if ($packet instanceof OpenPGP_SecretKeyPacket || $packet instanceof Crypt_RSA || $packet instanceof ArrayAccess && $packet[0] instanceof OpenPGP_SecretKeyPacket) {
$keys = $packet;
$message = $this->message;
} else {
$keys = $this->key;
$message = $packet;
}
if (!$keys || !$message) {
return NULL;
}
// Missing some data
if (!$keys instanceof Crypt_RSA) {
$keys = new self($keys);
}
foreach ($message as $p) {
if ($p instanceof OpenPGP_AsymmetricSessionKeyPacket) {
if ($keys instanceof Crypt_RSA) {
$sk = self::try_decrypt_session($keys, substr($p->encyrpted_data, 2));
} else {
if (strlen(str_replace('0', '', $p->keyid)) < 1) {
foreach ($keys->key as $k) {
$sk = self::try_decrypt_session(self::convert_private_key($k), substr($p->encyrpted_data, 2));
if ($sk) {
break;
}
}
} else {
$key = $keys->private_key($p->keyid);
$sk = self::try_decrypt_session($key, substr($p->encrypted_data, 2));
}
}
if (!$sk) {
continue;
}
$r = OpenPGP_Crypt_Symmetric::decryptPacket(OpenPGP_Crypt_Symmetric::getEncryptedData($message), $sk[0], $sk[1]);
if ($r) {
return $r;
}
}
}
return NULL;
/* Failed */
}
/**
*/
public function decrypt($msg, $key)
{
$decryptor = new OpenPGP_Crypt_RSA($key->message);
$elgamal = null;
foreach ($msg->message as $val) {
if ($val instanceof OpenPGP_AsymmetricSessionKeyPacket) {
$pkey = $decryptor->key($val->keyid);
if (!$pkey instanceof OpenPGP_PublicKeyPacket) {
continue;
}
switch ($pkey->algorithm) {
case 1:
case 2:
return new Horde_Pgp_Element_Message($decryptor->decrypt($msg->message));
case 16:
$elgamal = new Horde_Pgp_Crypt_Elgamal($pkey);
/* Put encrypted data into a packet object to take
* advantage of built-in MPI read methods. */
$edata = new OpenPGP_Packet();
$edata->input = $val->encrypted_data;
$sk_data = $elgamal->decrypt($edata->read_mpi() . $edata->read_mpi());
$sk = substr($sk_data, 1, strlen($sk_data) - 3);
/* Last 2 bytes are checksum */
$chk = unpack('n', substr($sk_data, -2));
$chk = reset($chk);
$sk_chk = 0;
for ($i = 0, $j = strlen($sk); $i < $j; ++$i) {
$sk_chk = ($sk_chk + ord($sk[$i])) % 65536;
}
if ($sk_chk != $chk) {
throw new RuntimeException();
}
return new Horde_Pgp_Element_Message(OpenPGP_Crypt_Symmetric::decryptPacket(OpenPGP_Crypt_Symmetric::getEncryptedData($msg->message), ord($sk_data[0]), $sk));
}
}
}
throw new RuntimeException();
}
