Scalable Group Key Management Protocol Based on Key Material Transmitting Tree

The group key management is one of the most crucial problems in group communication. In dynamic and large-scale groups, the overhead of key generating and key updating is usually relevant to the group size, which becomes a performance bottleneck in achieving scalability. Therefore, scalable group key management protocol, which is independent from group size, is the basis for wide applications of group communication. The paper proposes a novel group key management protocol, which designates un-trusted routers over Internet as transmitting nodes to organize a key material transmitting tree for transmitting key material. Members in group that are partitioned into subgroups attach to different transmitting nodes, and compute SEK using received key material and own secret parameter. The overhead of key management can be shared by the transmitting nodes which can not reveal the data of group communications, and the overhead for key management of each transmitting node is independent of the group size. In addition, the new protocol conduces to constant computation and communication overhead during key updating.