Encipherment and Conditional Access

We aim at modeling conditional access in any television environment (terrestrial broadcasting, cable and satellite). After defining the subject by saying what conditional access is, two models are presented. They correspond to two different systems, wide-spread in Europe: — The first model distributes control words. It is illustrated by “Discret 1”, a proprietary system used by about 3 500 000 subscribers of Canal-Plus in France. — The second model distributes authorizations. It is illustrated by “Eurocrypt”, an open system used by about 800 000 receivers throughout Europe: Filmnet and Kinnevik (600 000), Canal-Plus (60 000), France Telecom (50 000), Polycom, Maxat, KabelKanal,… — The emergence of digital signals technically facilitates the design of open systems. The use of a strong cryptography becomes justified. The encipherment techniques appear at three different levels: — for scrambling the program components, — for controlling the access rights, — for managing the access rights and for updating the authorization keys. — This modelisation emphasizes the impact of standardization and the reserves for further evolution. The knowledge harvested on existing systems allows to determine the axes for additional developments, specifically in relation with digital television.

Published

1994-01

Content type

Original Research

DOI

10.5594/M001282

ISBN

978-1-61482-945-4