I love hacking, as I really like finding badly written games, which have zero security. I understand how those things work, I understand how you hack a game. Thus, I know how you can protect your game from being hacked.
Because you might not choose me, but I still like to help, I'll tell you something VERY important: never ever trust the client side. Ever. If you implement your security only on the client side - your game will be hacked. There's no exceptions. So the security should be put on the server side.
Feel free to ask me to hack your games, to make sure they are secure.