Constant-round password-based authenticated key exchange protocol for dynamic groups

Abstract

In this paper, we extend the work of Abdalla et al. to take into account the notion of dynamicity in the membership and present an improved compiler that transforms any provably secure password-based authenticated 2-party key exchange into a more attractive password-based authenticated group key exchange. The resulting protocol is a provably secure and efficient dynamic password-based authenticated group key exchange protocol in a constant number of rounds. To the best of our knowledge, our proposal is the first solution to design constant-round password-based authenticated group key exchange protocols for dynamic groups. Furthermore, its security result does not assume the Random Oracle model or the ideal cipher model. © 2008 Springer-Verlag Berlin Heidelberg.