Secure Group Communications Using Twisted Group Rings

Abstract

In this paper we introduce a Group Key Management protocol following the idea of the classical protocol that extends the well-known Diffie–Hellman key agreement to a group of users. The protocol is defined in a non-commutative setting, more precisely, in a twisted dihedral group ring. The protocol is defined for an arbitrary cocycle, extending previous key agreements considered for two users. The main objective of this work is to show that there is no lack of security derived from the fact that a larger amount of public information is known by an external observer.