Tecmint: ionCube is a commercial software suite consisting of a PHP encoder, package foundry, bundler, a real time site intrusion detection and error reporting application as well as a loader.
PHP encoder is an application for PHP software protection: used to secure, encrypt and license PHP source code. ionCube loader is an extension used to load PHP files protected and encoded using PHP encoder. It is mostly used in commercial software applications to protect their source code and prevent it from being visible.