International Association for Cryptologic Research
Recently, the researcher proposed a new group key agreement protocol for imbalanced mobile networks, called HB-12 protocol. They claimed that their protocol can satisfy requirements: contributiveness, message integrity, resilience against passive attack and forward/backward secrecy for joining/removing operation. Recently, Islam and Biswas proposed a pairing-free identity-based authenticated group key agreement protocol for imbalanced mobile networks. However, in this paper, the authors point out that this protocol cannot resist passive attack and cannot provide forward secrecy for joining operation and backward secrecy for leaving operation.