Scalable key exchange transformation: from two-party to group

A modular method which derives a scalable construction of a group key exchange (GKE) scheme from a two-party key exchange (KE) one is presented. By combining the method presented with the compiler by Katz and Yung (see Advances in Cryptology-CRYPTO 2003, Springer-Verlag, LNCS, 2729, p.110-125) a scalable compiler can be obtained that transforms any two-party KE protocol secure against a passive eavesdropper to an authenticated GKE one secure against a stronger active adversary.