I''ve read a number of posts on the prevention of cheating and they all seem to agree that the less the client knows and does the better. But what if it is necessary for the client to handle more of the game code / state? Take the case of a procedurally generated galaxy where you have a couple of thousand users each in a completly separate area on different planets engaged in combat with hordes of aliens. Instead of the server running what would literally be a couple thousand separate games, the client is allowed to handle the movement / combat in these unique zones and reports the results back to the server. Now, a system like that is begging to be hacked, so what preventions can be used? One method is for the server to analyse the battle reports and reject any ridiculous results(but I really did kill 1000 aliens with my bare hands). I heard that NeverWinter Nights will be using a system like this to limit exp and treasure gained over a set time period. Since only a relatively few people have the ability and desire to hack games, the trouble only really starts once their trainers and scripts are "published" on the internet. So, what if every single client was given a unique patch (based on CD-Key) to make the exe unique. That way the hack would only work on the specific client.exe that the hacker had access to and would be useless on every other client. Each time the user downloaded a new version, the patch would be customized around his CD-Key. Would this system be feasible, reasonable etc? All comments appreciated... Korvan