Cycle-based limitation for cryptographic keys to be used in multimedia subscription services

If the results of the latest studies of ABI Research for Internet usage are to be believed, worldwide twelve million TV consumers will be using Internet Protocol Television (IPTV) instead of the traditional TV broadcasting by the end of 2010. Furthermore, analysts of Informa Telecoms & Media are forecasting the worldwide grow in revenue of IPTV to be ten billion US dollar by 2010. The revolution that is described by these figures implies on the one hand an enormous increase in sales values but on the other hand causes problems in handling the data volume. Moreover, IPTV will be attracting criminal attacks like Pay-TV has in traditional broadcasting. Therefore, not only efficient encoding of media data has to be applied to save transmission capacity, but also security mechanisms should be established to prevent unauthorised access. Interesting and promising encryption schemes which can be seamlessly integrated have been proposed in the past. Unfortunately, most of these outstanding solutions missed to cover key generation and management. This paper will unveil methods for both qualitative and cycle-based conditional access (CA).