I'd like to ask how to protect my code that is running on a client server from being altered and/or copied.
It's running on Ubuntu Server with the standard Apache Php Mysql stack.
Any software needed would preferably be open-source.
I'd also like to terminate the application when there is a license problem.
Doing this using my code is possible but since it's php the client could alter the code to prevent this from happening.
Best Answer
If you need to protect some magnificent algorithm you could have the code sitting on your own server with an authenticated API to access it, then distribute programs that use that API and sell credentials to use that API. It would then be possible to control code access as you pleased. This would be a sort of a software as a service type system that can be very effective in combating software piracy.
However this system has many potential flaws, one of which is it will be very difficult to persuade customers to trust this system knowing that if your company removes it's servers then they also lose theirs along with any investment of time/money into using the service.
Also the cost/maintenance would be substantial considering you would need to be able to support the combined traffic of all your customers received.
It would probably be easier to provide updates/support so people continue to pay for your services. I think it would be worth considering advice given on how to disable copying data from a webpage that any sort of protection that can easily be broken may not be worth the development effort and may annoy legitimate users and instead add value to continuing to pay for a licence.