Great thanks for the suggestions

I guess i didnt think about how many times it will have to cipher everything :s, and would probably cause more problems, i have thought of another way to this... i was think that when the client first makes a connection it sends 2 CRC's or Hash strings, 1 being the players username and the other being a random hash, then these will be stored in both the communication will be ignoured unless these 2 match?

Encryption is'nt really what im worried about since nothing secure needs to be sent, except in the first message, all other communications will only be that of position data.

Yeah the game is far from complete, its just a case of getting it out of the way ops:
And because my world engine and scene editor are heavily mixed in with the server/clients i thought it would be good to get it done now.