Is there any way i encode a file and give it to my clients without them asking their servers to install zend/codeguard... decoder modules ? Those things are completely useless because many client servers don't have the decoder. I need encryption to protect the system core file that will ensure people don't remove the copyright line without having the script stop working, i want this because nearly nobody linked back in my previous scripts so this time i will force them
Nope, it's impossible. All you can do is obfuscate, which is not really a protection at all. Well, it's not really impossible if they stil have older versions of PHP. I believe ioncube can be loaded at runtime until about PHP 5.2.x via dl() Anyway, most servers have ioncube or zend installed, i'm not sure which hosts you've found that don't?
Use ioncube, which does not require a server module to be "installed". You can distribute the decoder with the application, and it can be loaded as your web page is loaded.
Any other solution you find is just going to require the server to have something else installed. You might as well go with something already in use. Unless you develop something of your own. It's always easier to change a business model than it is the way people react to a model.