Multiway Tree-Based Group Key Management Using Chinese Remainder Theorem for Multi-Privileged Group Communications

Key management becomes more difficult in multi-privileged communications due to the dynamic membership and the complex relations between users and resources. In this paper, we propose a novel key management scheme in which the key graph is based on multiway trees. Chinese remainder theorem is employed to combine some encrypted rekeying materials into a short message for rekeying. As a result, users can update affected keys through the rekeying material and one-way function by themselves. The security analysis shows forward and backward security can be maintained. Compared with some existing schemes, our proposed scheme can reduce rekeying overhead efficiently.