Anyone care to explain how it works? I don't really want code...I'm just interested on how Blizzard does it.

I may be wrong here, but I'll see if I can explain it.

When you connect to Battle.net and view the packets you will notice the server sends values for A, B, C. Since these are fairly large numbers I'm assuming that it could be a prime factor encryption it uses (www.rsasecurity.com). But, I could be way off. Skywing should know the general gist since BNLS hashes the key correctly ;).

hehe thats CR, and it uses a customized checksum. the cdkey is decoded using some screwball complex method into several values that are hashed using modified a SHA-1 algorithm.

[color=red] * Camel points out that c0ol explained _decoding_ cd key[/color]

cd key _hashing_ uses the same function (Broken SHA-1) that you will use whenever you hash something for bnet (unless WAR3 uses a different hashing method, which is unlikely). to hash the cd key you need to first decode the cd key, and then send the values returned through your Broken SHA-1 function.

also note that the old cd key packet (0x36) used a different _hashing_ method--it's basicly the same exact thing, except for a few minor changes that drasticly change the end result.

isnt that what i said?

[quote author=c0ol link=board=17;threadid=1011;start=0#msg7594 date=1050096944]
isnt that what i said?
[/quote]
i was just elaborating

Well the general CD key thing lol.