Imagesource: https://fabiensanglard.net/

Anyone who grew up with technology from the 70s and 80s has certainly passed by pay TV decoders. 📺

My personal interest was first aroused when the analog version of Nagravision (I think in 1997) could be cracked in real time with the help of a Pentium II CPU and its MMX extension. The whole thing had its limitations, but found perfection in Xawtv under Linux, and was responsible for a good part of my very own cineastic pleasure. 🏴‍☠️

Fabien Sanglard recently looked at a predecessor system: Discreet11 - then used by Canal+, the first private payTV in France.

Discreet11 was an analogue encoding mechanism based on the SECAM standard used in France and was extremely efficient. Today, any pocket calculator could probably perform a line similarity analysis in real time, and decode the signal just like that. The problem with this is that Discreet11 is no more used today as terrestrial TV is still on air. 

But Fabien's article on the subject is really interesting. Especially because it also goes into additional mechanisms for securing the decryption and distribution process.