Distributed Group Key Management Using Multilinear Forms 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. Since centralized key management schemes have the drawbacks of the single point of failure and performance bottleneck, distributed key management schemes are proposed to solve the problem. In this paper, we propose a distributed key management scheme using multilinear forms for multi-privileged group communications. The identifications are assigned to service groups (SGs) and session keys (SKs). Based on the relationship of SGs and SKs, a derivation technique is designed to allow the SG servers to efficiently determine the affected SKs on their own according to the identification of the SG in which membership changes. For one leaving/switching operation, a uniform rekeying material is negotiated between the related SGs by using multilinear forms. As a consequence, the affected SGs can deduce all the affected SKs through the previous keys or with the rekeying material by using one-way function. The security analysis shows that the proposed scheme is secure. The performance evaluation shows the proposed scheme reduces the communication cost greatly.