One Round Group Key Exchange With Forward Security in the Standard Model

Constructing a one round Group Key Exchange (GKE) protocol that provides forward secrecy is an open problem in the literature. In this paper, the authors investigate whether or not the security of one round GKE protocols can be enhanced with any form of forward secrecy without increasing the number of rounds. They apply the key evolving approach used for forward secure encryption/signature schemes and then model the notion of forward security for the first time for key exchange protocols. This notion is slightly weaker than forward secrecy, considered traditionally for key exchange protocols. They then revise an existing one round GKE protocol to propose a GKE protocol with forward security.