Andy-Coder is a script written in PHP that helps you as a php-developer to code the source-code of your php-scripts in order to make it very difficult to read for users by exchanging 'speaking variables' with long numeric-variables based on numbers, selected by chance.
You can use it, for example, to code free trial-versions of your script. Just give it a try and download the free-trial version to see if the script can be useful for you.
Startpage - http://www.andreashuebner.com - with more free php-scripts