anti-cheat for online multiplayer first person shooter

I want an anti-cheat created for a Quake3/idTech3 game from 2003. There is a lot of information out there, available to be browsed as a resource to assist you. There are plenty of cheats and some source code for cheats out there as well. The game also had it's source release. I need it for a specific mod which hasn't been updated since 2006. I can possibly get in touch with one of the developers of that mod as well as the latest patch for the game itself. if that would help. I have a decent amount of knowledge when it comes to this topic as well, but I can't go and make my own anti-cheat. I'm leaving the skills required default since it doesn't really matter how it's done as long as it gets done, but the game is in C++ I believe.