TPS-Crypt
TPS-Crypt is a Conditional Access System used to protect digital TV content from unauthorized viewing. It was developed by France Telecom, as it is a modification of the Viaccess PC2.3 Conditional Access System that incorporates Advanced Encryption System (AES) keys. Like Viaccess PC2.3 and another modification of it, ThalesCrypt, TPS-Crypt was eventually compromised by crackers to enable illegal viewing of pay TV content.
At the time the system was set to update the AES key on a daily basis, but it was found to only inconvenience illegal viewers little, and so the system was changed to update the key every 12 minutes. Since only TPS receivers could receive the key update, this was an effectively strategy. Crackers took one step further by managing to develop a system that successfully predicted key changes, but even though it would have been an effective hack, it wasn't possible to implement on most satellite receivers.