PHP is obviously an Open Source project. Usually, its applications are also distributed with Open Source licenses, granting everybody access to their PHP source code.
However, some PHP application authors have the need to protect their source code, either to protect their intellectual property and not let others taking advantage of it for free, or to make it more viable to sell copies of commercial versions of their projects, or even for security purposes making it more difficult for unauthorized people to obtain ilicit access to the applications source code.
There are some free and commercial solutions for protecting PHP source code. However, most of these solutions require external PHP extensions to execute the protected code.
This class provides a solution that only requires PHP code to protect and execute PHP code.