Description:
------------
The implementation of Serpent in PHP not passes test from Serpent AES submission. As a result, the sting encrypted by PHP MCrypt can not be decrypted in other programming languages (I tried C# and Bouncy Castle support tried Java). If we use same key and iv, then PHP results for decrypt or encrypt differs from other programming languages.
More details: https://github.com/bcgit/bc-csharp/issues/13#issuecomment-38490830

Test script:
---------------
<?php
function crypt_test($algo, $mode, $key, $iv, $name, $plaintext, $expected) {
    $cipher = mcrypt_module_open($algo,'',$mode,'');
    mcrypt_generic_init($cipher, $key, $iv);
    $encrypted = mcrypt_generic($cipher, hex2bin($plaintext));

    printf("%s/%s %s:\n expected: %s\n   actual: %s\n", $algo, $mode, $name, bin2hex($encrypted), $expected);

    mcrypt_generic_deinit($cipher);
    mcrypt_module_close($cipher);
}

$key = hex2bin('00000000000000000000000000000000');
$iv = hex2bin('00000000000000000000000000000000');

crypt_test('serpent', 'ecb', $key, $iv, 'zeros', '00000000000000000000000000000000', 'e9ba668276b81896d093a9e67ab12036');
crypt_test('serpent', 'ecb', $key, $iv, 'I1', '80000000000000000000000000000000', '10b5ffb720b8cb9002a1142b0ba2e94a');
crypt_test('serpent', 'ecb', $key, $iv, 'I2', '40000000000000000000000000000000', '91a7847ef1cd87551b5b4bf6f8e96e2c');
crypt_test('serpent', 'ecb', $key, $iv, 'I3', '20000000000000000000000000000000', '5d32aece8383fb2ee22cb4a6061d1429');

?>

Expected result:
----------------
serpent/ecb zeros:
 expected: 3620b17ae6a993d09618b8768266bae9
   actual: 3620b17ae6a993d09618b8768266bae9
serpent/ecb I1:
 expected: a3b35de7c358ddd82644678c64b8bcbb
   actual: a3b35de7c358ddd82644678c64b8bcbb
serpent/ecb I2:
 expected: 04abcfe4e0af27ff92a2bb10949d7dd2
   actual: 04abcfe4e0af27ff92a2bb10949d7dd2
serpent/ecb I3:
 expected: 8f773194b78ef2b2740237ef12d08608
   actual: 8f773194b78ef2b2740237ef12d08608

Actual result:
--------------
serpent/ecb zeros:
 expected: 3620b17ae6a993d09618b8768266bae9
   actual: e9ba668276b81896d093a9e67ab12036
serpent/ecb I1:
 expected: a3b35de7c358ddd82644678c64b8bcbb
   actual: 10b5ffb720b8cb9002a1142b0ba2e94a
serpent/ecb I2:
 expected: 04abcfe4e0af27ff92a2bb10949d7dd2
   actual: 91a7847ef1cd87551b5b4bf6f8e96e2c
serpent/ecb I3:
 expected: 8f773194b78ef2b2740237ef12d08608
   actual: 5d32aece8383fb2ee22cb4a6061d1429