Depends on what you mean.

Are you trying to protect the clients resources or just cheaters.

for cheating, ue encryption, and just update the encrytion with each update. Not only that, but create a bot to monitor suspicious activity, such as a report a player that levels really fast, and ip ban players that managed to level tremenously high in an impossible amount of time.

It's all about coming up with untamperable solutions that monitor activity and activly supports both the client and server in protecting against unfair play.