I actually believe it's referring to Assassin's Creed 2. It had to check in with the central server to see if a legitimate copy was being played, and the way it was cracked was basically going through every possibility where the check can fire off, recording the request/response, and having the cracked version play back the appropriate response to the request. It basically had to be exhaustively played to get to a point where all the request/response combinations got recorded.