PHP custom crypt and decrypt function

crypto.php

//Source: https://stackoverflow.com/questions/15194663/encrypt-and-decrypt-md5

function encryptIt( $q ) {
  $cryptKey = 'блалалаѝк777амайка';
  $qEncoded = base64_encode( mcrypt_encrypt( MCRYPT_RIJNDAEL_256, md5( $cryptKey ), $q, MCRYPT_MODE_CBC, md5( md5( $cryptKey ) ) ) );
  return( $qEncoded );
}

function decryptIt( $q ) {
  $cryptKey = 'блалалаѝк777амайка';
  $qDecoded = rtrim( mcrypt_decrypt( MCRYPT_RIJNDAEL_256, md5( $cryptKey ), base64_decode( $q ), MCRYPT_MODE_CBC, md5( md5( $cryptKey ) ) ), "\0");
  return( $qDecoded );
}