Ioncube loader is a PHP module to load files that were protected with the Ioncube Encoder software. Ioncube is often used by commercial PHP software vendors to protect their software, so it is likely that you come across an Ioncube encoded file sooner or later when you install extensions for CMS or Shop software written in PHP. In this tutorial, I will explain the installation of the Ioncube loader module in detail for CentOS, Debian, and Ubuntu.