LOCK-11 was designed on an established principle that relied on two levels of security. A user had to have a valid ID and password, as usual, but in addition that ID and password would only work when entered from authorized terminals, an approach called terminal-based security . To defeat the system, a hacker would need not only to have knowledge of an account ID and password, but would also have to enter that information from the correct terminal. The method was well established, and the inventors of LOCK-11 were convinced it would keep the bad guys out. We decided we were going to teach them a lesson, and earn three hundred bucks to boot.