Which CD Key?

I want to have a separate key to play DayZ legitimately. Basically I want to buy the game on a new Steam account and change my key with that one. My question is, what key does DayZ run on, so which game do I need to purchase and use the key from, Arma 2 or OA? Hope that makes sense, lol.

Arma 2 OA /short

I thought that was it, just wanted to double check. Thank you

No problem, best of luck.