KAP-AOT: A Novel Group Key Agreement Protocol Based on Considering Nodes´ Average Online Time

An effective group key agreement protocol is important for group-oriented applications. Some key tree approaches have been proposed by other researchers. The rekey cost of some of them scales with the logarithm of the group size for a join or leaving request, in which TGDH (tree based group Diffie-Hellman) is considered as one of the most effective and secure protocols. But the rekey cost is still considerable when the group size is very large and with nodes´ frequent joining and leaving (churn problem). In this paper, we present a novel group key agreement protocol KAP-AOT improved on TGDH protocol. Our protocol takes nodes´ average online time into consideration and is proved to be able to further reduce computation overhead of the rekey process.