This paper indicates that Burmester et al.’s group key agreement protocol which based on the authenticated broadcast channel is unable to withstand the disruption attack and key-control attack of malicious participants in group.These two attacks lead that other honest participants will compute different session key and other honest participants compute the fixed session key which is determined previously by malicious participants

respectively.In this paper

a fault-tolerant group key agreement (FT-GKA) protocol is proposed.Even if there are malicious participants trying to attack the establishment of a session key

all other honest participants following the proposed protocol are still able to compute the correct session key using the digital signature technology.Paper proves the protocol can withstand the passive attack of adversary under the DDH assumption

and the protocol can withstand the interrupted attack and key-control attack from malicious participants under the DL assumption and the random oracle model.Furthermore

the proposed protocol possesses both constant number of rounds and lower computation overhead.