Paper 2006/214

Password-Authenticated Constant-Round Group Key Establishment with a Common Reference String

Jens-Matthias Bohli and Maria Isabel Gonzalez Vasco and Rainer Steinwandt

Abstract

A provably secure password-authenticated protocol for group key establishment in the common reference string (CRS) model is presented. Our construction assumes the participating users to share a common password and combines smooth hashing as introduced by Cramer and Shoup with a construction of Burmester and Desmedt. Our protocol is constant-round. Namely, it is a three-round protocol that can be seen as generalization of a two-party proposal of Gennaro and Lindell.

Note: Updated protocol and extended proof.