Włącz McRypt w PHP INI w XAMPP PHP.INI

First, you should download the suitable version for your system from here: https://pecl.php.net/package/mcrypt/1.0.3/windows

Then, you should copy php_mcrypt.dll to ../xampp/php/ext/ 
and then enable the extension by adding extension=mcrypt to your xampp/php/php.ini file.
  
It works for me.
Ankur