/**
 * PKCS padding works by adding n padding bytes of value n to make the total 
 * length of the data a multiple of the block size. Padding is always added 
 * so if the data is already a multiple of the block size n will equal the 
 * block size. For example if the block size is 8 and 11 bytes are to be 
 * encrypted then 5 padding bytes of value 5 will be added.
 *
 * @param $text, The text that you want to encrypt
 * @param $blocksize, The block size of you algorithm e.g. 128 / 8 = 16
 */
function pkcs5_pad ($text, $blocksize)
{
    $pad = $blocksize - (strlen($text) % $blocksize);
    return $text . str_repeat(chr(11), $pad);
}

/**
 * Encryption
 *
 * @param $text, The text that you want to encrypt.
 * @param $crypt = 1 if you want to crypt, or 0 if you want to decrypt.
 */
function bakery_mix($text, $crypt) {
  $key = variable_get('bakery_key', '');

  $td = mcrypt_module_open('rijndael-128', '', 'ecb', '');
  $iv = mcrypt_create_iv(mcrypt_enc_get_iv_size($td), MCRYPT_RAND);

  $key = substr($key, 0, mcrypt_enc_get_key_size($td));

  mcrypt_generic_init($td, $key, $iv);

  if($crypt) {
    $encrypted_data = mcrypt_generic($td, pkcs5_pad($text));
  }
  else {
    $encrypted_data = mdecrypt_generic($td, trim($text));
  }

  mcrypt_generic_deinit($td);
  mcrypt_module_close($td);

  return $encrypted_data;
}