File encryption

An encryption file is included with this section, and can be found here.

Even though all your important game information is stored on the server, the client can still edit your files to their advantage. One example may be editing the map files to remove all graphics that players can hide behind so they can see every player/NPC. Or they could go straight to the graphic files and clear them so those objects don't obstruct their view. You could also have partially-invisible characters that are very hard to see for cloaked characters, and the client can edit them so they are as clear as day.

As with most information on the client, theres no "preventing", just "obfuscating". You can have the client send the MD5 hash of every file to make sure they were not edited, but the client can just edit that packet to what the server wants to see.

There are plenty of routines out there for file encryption, varying in speed and security. Often, you will want to go with the faster routines such as XOR and RC4 encryption unless security becomes an issue. Your best bet with these files are just to encrypt them, and hope for the best. You don't want to spend too much time on this because even if the file is impossible to decrypt, you have to load it into memory at some point, and it can just be edited there.