Efficient secure group management for SSM

We propose an approach to channel key management in the architecture S-SSM, we designed to secure SSM communication. S-SSM defines two mechanisms for access control and content protection. The first one is carried out through subscriber authentication and access permission. The second is realized through the management of a unique key, called the channel key, k_ch, shared among the sender and subscribers. The management of k_ch is based on a novel distributed encryption scheme that enables an entity to efficiently add and remove a subscriber without affecting other subscribers.