An Insider-Resistant Group Key Exchange Protocol without Signatures

The well-known method for a group key exchange (GKE) protocol to be against insider attack is to make use of signatures. However, using signatures considerably degrades the performance of the GKE protocol. In this paper, we propose a new method to resist insider attack. The underlying tool of our method is a two-party authenticated key exchange (AKE) protocol, which can be used to authenticate all other participants´ session identifiers instead of using signatures. Based on the two- party AKE protocol, we propose an efficient insider-resistant GKE protocol without signatures. We show that our proposal is provably secure against insider attack if the underlying two-party AKE protocol is secure.