do you know how i can encript my php code for free.

im interested in encrypting my php script but i have not found an open source software to do that. i found some encryption software but you have to buy them like zend for example

i have a linux server with you and i was wondering if you can guide me on where i can go to find encripting software for php. i want to protect my code and i really need to do this. but how do i do this? or where do i even start making my code encrypted. i hear its very hard to do but atleast if you can show me where to start encripting my code i can go from there. there are not alot of php encrypters out there and i've only found the ones you can pay for their software to encript.