An efficient pairing‐free identity‐based authenticated group key agreement protocol

Summary An authenticated group key agreement protocol allows participants to agree on a group key that will be subsequently used to provide secure group communication over an insecure network. In this paper, we give a security analysis on a pairing‐free identity‐based authenticated group key agreement because of Islam et al. We show that the protocol of Islam et al. cannot satisfy the minimal security requirements of the key agreement protocols. We propose an efficient pairing‐free identity‐based authenticated group key agreement for imbalanced mobile network. The proposed protocol can be implemented easily for practical application in mobile networks as it is free from bilinear. Under the difficulty of the InvCDH and CDH we demonstrate that the proposed protocol provides perfect forward secrecy, implicit key authentication and the dynamic functionality. As compared with the group key agreement protocols for imbalanced mobile network, the proposed protocol provides stronger security properties and high efficiency. Copyright © 2013 John Wiley & Sons, Ltd.