: These programs attempt to generate valid product keys on the fly. In the context of the first ETS, a user on a forum noted that the game's product key check never contacted a central database to verify the key's legitimacy. This meant that a keygen or any number of generic keys could work. A classic example of such a code, found on an online Q&A site, is NPPXO-NKW6Q-HW2XN-FC4WV-S3ADT .