A common conditional access interface for digital video broadcasting decoders

A set of standards has been designed by the Digital Video Broadcasting (DVB) project in Europe for the broadcasting of digital television services on satellite, cable, MMDS and terrestrial networks. These standards are based on the ISO MPEG 2 specifications and include source coding, channel coding, modulation, service information and interfaces for consumer decoders. A conditional access system is used when there is a need to control the access to a broadcast service, mainly for commercial reasons. It has been decided not to standardize the conditional access (CA) system, but only the mechanisms for interoperation of different CA systems on DVB decoders. Mechanisms had to be found in order to allow the reception of DVB programmes using different CA systems with a single decoder. The DVB common interface described in the paper has first been specified for that purpose. Decoder manufacturers will provide DVB decoders with the DVB common interface and CA system providers will provide detachable CA modules. This solution allows broadcasters to use modules containing solutions from different suppliers in the same broadcast system, thus increasing their choice and anti-piracy options