From what I've seen its just a matter of passing a string with the checksums to the server that it expects to see, but I've not dug any further then that. Lets face it, this game is opensource, and its going to have hacks added to it, regardless of our conversations on the forums.
Thank goodness most people reading this are not C programmers. Unfortunately though, some of these things (like the helmet hack) are just so easy anyone can do them.