Optimizing the Rekeying Cost for Contributory Group Key Agreement Schemes
Abstract—
Although a contributory group key agreement is a promising solution to achieve access control in collaborative and dynamic
group applications, the existing schemes have not achieved the performance lower bound in terms of time, communication, and
computation costs. In this paper, we propose a contributory group key agreement that achieves the performance lower bound by
utilizing a novel logical key tree structure, called PFMH, and the concept of phantom user position. In particular, the proposed scheme
only needs Oð1Þ rounds of the two-party Diffie-Hellman (DH) upon any single-user join event and Oðlog nÞ rounds of the two-party DH
upon any single-user leave event. Both the theoretical bound analysis and simulation show that the proposed scheme achieves a lower
rekeying cost than the existing tree-based contributory group key agreement schemes.