75. Study of Proxy Re-cryptography in Group Key Management for Group Communications System

This paper presents a group key management mechanism PTGKM based on hierarchical and domain structure in Near-Space Network. The mechanism combines hierarchical and domain structure with the use of proxy re-cryptography algorithms. It has the following characteristics: (1) the core backbone network node cannot obtain the new group key. It only participates in the distribution of the new group key. So the mechanism solves the problem of a single point of failure of group key management based on hierarchical and domain structure; (2) The mechanism restricts the impact of group membership change in its domain, which improves the scalability of group key management scheme; (3) The inter-domain switching algorithm effectively reduces the rekeying overhead of the high mobile nodes’ frequent switching between different domains; (4) The mechanism adapts to the characteristics of Near-Space Network and meets the forward security and backward security. The analysis results show that, PTGKM mechanism is applicable to near space environment and has good scalability and reliability.