Secure Offline PHP Application

I want to build php application works though lan based system. I will install lamp and php project in server. From server ip address, i will access project on different computers though lan. But i won't allow others can see my functions and code in server. I want convert php to some encrypted format and run it which can't decrypte by users. Is there any methods to solve my problem and secure my project. I heard that php project can be converted to dll and run it. Please help me.