Cryptanalysis of Lee et al.'s authenticated group key agreement

Authenticated key agreement protocols are to authenticate the users who will start a conversation and establish a common session key. In 2009, Cheng-chi Lee et al. proposed a new authenticated group key agreement based on a novel bilinear pairing to provide integrity of the transmitted messages. In this paper, we show that Cheng-chi Lee et al.'s protocol can only ensure the validity between the second step and the third step, and the intermediate message between the first step and the second step can be disturbed by attackers. That is, Cheng-chi Lee et al.'s protocol doesn't achieve their goal. (C) 2011 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of [CEIS 2011]