mcrypt is no longer included in newer version of PHP or Debian 10
mcrypt, used by jirafeau to cipher the files is no longer included in PHP 7.2 or 7.3 In Debian 10, PHP 7.3 is the default PHP and can't use mcrypt.
Maybe you should use libraries from OpenSSL ?
Deprecated features in PHP 7.1.x
ext/mcrypt
The mcrypt extension has been abandonware for nearly a decade now, and was also fairly complex to use. It has therefore been deprecated in favour of OpenSSL, where it will be removed from the core and into PECL in PHP 7.2.
Thanks for your time and work,
Frédéric