IonCube Loader is a software tool, that is necessary to run files that are protected with ionCube PHP Encoder. The latter is an app used to make PHP code human unreadable, to protect it from reverse engineering and illegal use. Plenty of script-driven apps, particularly message boards, cms and e-commerce solutions are protected with ionCube PHP Encoder, which means that if you purchase a script and you notice that ionCube is among the hosting environment requirements, you need to make sure that your web hosting server has the instrument pre-installed. Though it is not that hard to set it up when you have your own server, it's almost impossible to do that on a shared hosting server due to the fact that the PHP environment should be precompiled and all of the clients on the server shall be affected.
