Minimum redundancy tree for key distribution in secure multicast

This paper proposes a "minimum redundancy tree" (MRT) for key distribution in secure multicast. The MRT is optimal in terms of minimum rekeying costs by keeping the minimum average number of keys to be updated for each member and maintaining minimum average tree height for each member. We also propose to combine MRT and subgrouping to generate multiple MRTs such that the rekeying costs can be further minimized when compared to that of other key management schemes.