An efficient fault-tolerant group key agreement protocol

Wen-Guey Tzeng

Kuo‐Hsuan Huang, Yu‐Fang Chung, Hsiu-Hui Lee +2 more

Yuh‐Min Tseng

Zi‐Yao Cheng, Yun Liu, Chin‐Chen Chang +1 more

SUMMARY A fault‐tolerant group key agreement is an essential infrastructure for Internet communication among all involved participants; it can establish a secure session key no matter how many malicious participants exit simultaneously in an effort to disrupt the key agreement process. Recently, Zhao et al. proposed an efficient fault‐tolerant group key agreement protocol named efficient group key agreement that can resist denial‐of‐service attacks, reply attacks, man‐in‐middle attacks, and common modulus attacks; it can also preserve forward secrecy with lower computational cost than previous protocols. We show that it is still vulnerable to active attacks by malicious participants and modify the corresponding security weakness adaptively. Furthermore, we propose an efficient fault‐tolerant group key agreement based on a binary tree structure and enhance it to a dynamic setting where participants can leave or join the group arbitrarily according to their preferences with instant session key refreshment. Additionally, our session key refreshment is based on secure key updating to protect forward/backward confidentiality and is resistant to active/passive attacks. The performance analysis shows that our proposed protocol has lower computational cost and little additional communication cost exploiting dynamic setting. Copyright © 2013 John Wiley & Sons, Ltd.

Lansheng Han

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.

Jens-Matthias Bohli