IonCube Loader is a tool, that's needed to run files that are protected with ionCube PHP Encoder. The aforementioned is an app designed to make PHP code human unreadable, in order to protect it from reverse engineering and / or illegal use. Numerous script-driven applications, in particular discussion forums, content management systems and electronic commerce solutions are encoded with ionCube PHP Encoder, which means that if you get a script and you notice that ionCube is on the list of website hosting environment requirements, you need to make sure that your web hosting server has the tool pre-installed. Although it's not that hard to set it up when you have your own server, it is close to impossible to do that on a shared hosting server because the PHP environment will have to be precompiled and all of the clients on the server will be affected.