Paper 2005/185

Security properties of two provably secure conference key agreement protocols

Qiang Tang and Chris J. Mitchell

Abstract

In this paper we exhibit security vulnerabilities in two authenticated group key agreement schemes based on the group key agreement protocol of Burmester and Desmedt. One scheme was proposed by Burmester and Desmedt, and uses a separate authentication scheme to achieve authentication among the participants. The other was generated using the general protocol compiler of Katz and Yung. We show that not only do they fail to achieve some of the claimed security goals, but they also suffer from other security vulnerabilities.