I am currently building an iOS MMO and I'm leaning towards using TCP as my networking protocol over the higher level HTTP (for the speed difference and the fact that it does not require the client to poll constantly for updates.)
Now, through my research I know that with MMO and any client-server multiplayer games, you should never trust what the client sends to the server. As an extension of that, you wouldn't want anybody to read your packets to see the contents so it's harder for them to send correctly formatted data to the server. (Maybe I'm paranoid.)
The only problem is, where in HTTP there is great support for a secure channel in HTTPS through SSL where the setup occurs mainly server-side, I am not aware of a way to achieve the same thing on TCP. Is there any resource I could be referred that could help me achieving similar security, or at least good enough, on both the iOS side and server-side?
On a side note, if the answer involves doing the encryption and decryption on the client-side, would that severely impact the performance of my application?