An efficient group key agreement protocol from bilinear pairings

A group key agreement protocol is designed to efficiently implement secure multicast channels for a group of parties communicating over an distrustful, open network by allowing them to agree on a common secret key. Recently some constant-round protocols have been proposed. However some of them are too expensive with computational complexity O(n), others with lower computational complexity doesn't ensure the participants to get the same session key. In this paper we propose a new constant-round protocol suited for groups consisting of many hosts with limited computational capability and a host with more computational power Then we prove its security.