Secure Mobile Content Delivery Using Dynamic Group Key Agreement with Batch Verification

Abstract

Recently, the bilinear pairings such as the Weil and the Tate pairings defined on algebraic curves over a finite field have found applications in the design of cryptographic protocols. One useful application in mobile environments is for secure group communication over a public network. The members in the group need to establish a common group key that will be used to encrypt messages to be broadcast to the group. Furthermore, it is important to update the group key with low computational costs when the members join and leave the group. In this paper, we propose a pairing-based key exchange protocol for dynamic groups. The proposed protocol achieves low communication complexity and provides some computational savings by the batch verification of signatures. We show that the security of our scheme is guaranteed against an active adversary in the random oracle model under the bilinear Diffie-Hellman (BDH) assumption.