Optimal Key Tree Structure in Secure Multicast
Multicast is often used to deliver packets to a group of users. To ensure security, a group key is used in secure multicast to encrypt group communication. Because of the dynamic group membership, the performance of key management becomes the core factor of secure multicast. This paper investigates key tree structure for group key management and proposes a new optimal key tree structure based on member updating probabilities. With this optimal tree structure, system costs can be properly reduced.It is verified by the experiment results that this key tree structure is better than other key tree structures based on member updating probabilities, and the bounds of this structure's average updating cost are analyzed.