mycrypt-test.php

<?php
require_once 'mycrypt.php';

$str = '3ryfbyevfibsd';
$enc = encrypt($str);
$dec = decrypt($enc);

header("Content-Type: text/plain");

echo $str ."\n";
echo bin2hex($enc) ."\n";
echo $dec ."\n";
?>

mycrypt.php

<?php
// Encryption Routines
define('ENCRYPTION_KEY', 'artofwar');
define('ENCRYPTION_ALGORITHM', 'rijndael-256');
define('ENCRYPTION_MODE', 'ecb');
define('ENCRYPTION_IV_SOURCE', MCRYPT_DEV_RANDOM); // Change to MCRYPT_RAND if Windows

define('MYCRYPT_ENC', 1);
define('MYCRYPT_DEC', 2);

function encrypt($string) {
  return mycrypt($string, MYCRYPT_ENC);
}
function decrypt($string) {
  return mycrypt($string, MYCRYPT_DEC);
}
function mycrypt($string, $meth) {
  $aes = mcrypt_module_open(ENCRYPTION_ALGORITHM, '', ENCRYPTION_MODE, '');
  if (!$aes) die('Unable to initialize encryption engine');
  
  $iv = mcrypt_create_iv(mcrypt_enc_get_iv_size($aes), MCRYPT_DEV_RANDOM);
  $key = substr(md5(ENCRYPTION_KEY), 0,
          mcrypt_enc_get_key_size($aes));
  
  mcrypt_generic_init($aes, $key, $iv);
  
  switch ($meth) {
    case MYCRYPT_ENC:
      $ret = mcrypt_generic($aes, $string);
      break;
    case MYCRYPT_DEC:
      $ret = rtrim(mdecrypt_generic($aes, $string), '\0');
      break;
  }
  
  mcrypt_generic_deinit($aes);
  mcrypt_module_close($aes);
  
  return $ret;
}
?>