It looks overly complicated.
And ineffective. Any comments on the system? :)
Sure:a) What happens when I reinstall my computer? My key is now "useless", so how do I get to play the game I've legally paid for?
b) Anyone with a packet sniffer and a bit of imagination, could brute force themselves a nice list of keys in a relatively short time.
c) Once they've done that, they can run them through pattern recognition software, and get all the keys you have invalidating any future purchases.