Efficient and secure conditional access system for pay-TV systems

摘要

In Digital TV service, subscribers get the access of channels of their interest. In Conditional Access Systems (CAS), multimedia content is delivered securely using the Control Word (CW). To frequent update of the CW, a large number of messages are exchanged in the conventional key distribution systems. In this paper, a centralized key distribution scheme based on dynamicity of the groups and with freedom of channel package composition is proposed. Scheme has also efficient mechanism of load balancing at Group Controller (GC) side. To speed up the search of the channel package in the existing database, Optimal Binary Search Tree (OBST) data structure and Finite State Machine (FSM) are used. Scheme also provides the efficient leaving and joining mechanism for single user as well as batch users.