Viaccess PC2.3 is a Conditional Access System developed by France Telecom. It is sometimes referred to as Viaccess 1, since it was the first Conditional Access System with the Viaccess name to be used to protect Digital Media Broadcast (DMB) content from unauthorized viewing. Viaccess 2.3 is one of five Viaccess systems in use. However, the Viaccess system is not secure and has been compromized by hackers. Using software hacks, set-top-boxes can be flashed to decrypt transmissions protected by Viaccess PC2.3 without the user having to pay a single cent in subscription fees. Viaccess PC2.3 was succeeded by Viacess PC2.4 but it also got it's own modifications
Viaccess PC2.3 Modifications
While the Viacess PC2.3 Conditional Access System is insecure, there are two main modifications of it. The first is TPS-Crypt. TPS-Crypt is a modified Viaccess PC2.3 with support for Advanced Encryption System (AES) Keys. This modification is technically insecure, but with the AES keys updating every 12 minutes, in most cases it is not viable to use a hacked receiver for unauthorized viewing. Crackers did get around this by creating a system that can predict keys accurately, but getting such a system to run on a satellite receiver is impossible most of the time.
The second main Viaccess PC2.3 modification is ThalesCrypt, which came along after the TPS-Crypt system was rendered insecure. It is an over-encryption mechanism of the original protocol encryption keys, and its used by Canal Satellite France.