Question about Portal 2 on PS3

[Don86]

I've heard that there is some sort of cd-key required when two players play together with seperate platforms on PS3 and PC's Steam service.

Does the multiplayer on PS3's portal 2 requires some sort of cd-key/online pass if both players play it on PSN?

I'm thinking of passing the CD-Key or online pass(if there is one) to PC gamer friend of mine who games regularly on steam.

Thanks in advance!