How to Pass Information to server safely?

[eluser]Devyn[/eluser]
Hi,

Following is the prototype of my app and please have a look at it.
http://staging-colorfulcloud.aptanacloud...eart_game/

If you check on the link of a cell, you'll see a session id followed by the value of card you choose.
For eg, following is the link of Player 4's C10 card.
http://staging-colorfulcloud.aptanacloud...d8c2d2/C10

My question if how can I pass that "C10" value to the server without user interruption(I mean I want to hide that value from user to prevent hacking).
The URL style is not fixed and it can be changed according to method.
I'm now storing that session data into database.

Please guide me and I really need your help, guys!
Thanks in advance!