Licensing system

Hello, I'm looking for something to protect my files/tool, i want to put a license key to them for free

You can do HMAC validation. Depends what language you're using but usually unique hash implementations are trivial.

I need to secure files, those are not written in Java :/

Really depends on how much time you have. One of my best experiences is to download files (e.g. DLLs in a win app) from a server and load them in memory. Then let your dependency file generate a checksum code relative to your server's unique HTTP header. If the thing does not match then you are dealing with an invalid license. In this way, you can generate unique hashes for every license request since there really is no pattern to crack a.k.a real polymorphism.

Try to make your app as most server dependable as possible.
So even if they get around license checking (most likely they will) they still can't use some of the functions.