An improved protocol for server-aided authenticated group key establishment

Abstract

Protocols for group key establishment enable a group of parties to build a secure multicast channel over insecure public networks. In this paper, we present a group key transfer protocol designed for use in the model where a trusted key generation center shares a long-term secret with each of its registered users. Our protocol is an improved version of the group key transfer protocol proposed recently by Harn and Lin. Improvement is made in three different aspects: security, efficiency and correctness. Our main contribution is in showing that Harn and Lin's protocol does not achieve implicit key authentication but can be fixed without causing any efficiency degradation. © 2011 Springer-Verlag.