An overview of security in Eurocrypt conditional access system

In accordance with a ruling of the European Economic Community (EEC), as from 1995, television receivers manufactured in Europe should incorporate D2-MAC decoder. One of the characteristics of this system is that it has a conditional access system (Eurocrypt) to make the services available to only those users who have previously subscribed to it. This proposed system of conditional access is described and later analyzed studying the cryptographical properties which characterise it. The encoding of the image, sound and data signals is based on stream cipher techniques. The cryptographic excellence of this type of encoding is determined by the suitable choice of encoding pseudo-random sequences. Although the system of encoding used-based on the Jennings (1980) generator is not very robust, the modifications which have been introduced and a suitable key management system, allows one to conclude that the standard D2-MAC conditional access system presents a robust cryptographic behaviour against cryptanalytical attacks, preventing fraudulent access by unauthorised users