Many group key agreement protocols (GKA) for secure group communication (SGC) based on the Diffie-Hellman key exchange principle have been proposed in literature. All of these protocols require member serialization and/or existence of a central entity. In this paper, we propose a simple group Diffie-Hellman key agreement protocol which removes these two limitations. Moreover, the new protocol n...

The Diffie-Hellman key agreement protocol, is a procedure that allows establishing a shared secret over an insecure connection and was developed by Whitfield Diffie and Martin Hellman in 1976, . This procedure is, often slightly modified, still used today by several applications. Before going into more detail on these applications, let’s have a look at the basic key-exchange method between two ...

A generalization of the original Diffie-Hellman key exchange in (Z/pZ) found a new depth when Miller [21] and Koblitz [9] suggested that such a protocol could be used with the group over an elliptic curve. In this paper, we extend such a generalization to the setting of a semigroup action (G-action) on a finite set. We define these extended protocols, show how it is related to the general Diffi...

We offer a public key exchange protocol in the spirit of Diffie-Hellman, but weuse (small) matrices over a group ring of a (small) symmetric group as the platform. This“nested structure” of the platform makes computation very efficient for legitimate parties.We discuss security of this scheme by addressing the Decision Diffie-Hellman (DDH) andComputational Diffie-Hellman (CDH) p...

With the advance of multicast communication infrastructures several works address the task of sharing a session key among a group of users. Some of theses works extend the Diffie-Hellman protocol to the multi-party setting but can not by lack of adequate formal models provide stringent arguments to support the security of their protocols. Fortunately, formal models and formal treatments have re...

In 1976, Diffie and Hellman in their path breaking paper [5] proposed a two party key agreement protocol based on finite field. Diffie – Hellman Key Exchange Protocol [DH protocol] has unique importance in two party wireless communication scenarios. After this protocol several protocols have been proposed bases on DH protocol but the Man in the middle attack raises a serious security concern on...

We present a cryptographically sound formal method for proving correctness of key exchange protocols. Our main tool is a fragment of a symbolic protocol logic. We demonstrate that proofs of key agreement and key secrecy in this logic imply simulatability in Shoup’s secure multi-party framework for key exchange. As part of the logic, we present cryptographically sound abstractions of CMA-secure ...

Many authentication and key exchange protocols are built using an accepted set of standard concepts such as Diffie-Hellman key exchange, nonces to avoid replay, certificates from an accepted authority, and encrypted or signed messages. We introduce a basic framework for deriving security protocols from such simple components. As a case study, we examine the structure of a family of key exchange...

We revisit the password-based group key exchange protocol due to Lee et al. (2004), which carries a claimed proof of security in the Bresson et al. model under the intractability of the Decisional Diffie–Hellman problem (DDH) and Computational Diffie–Hellman (CDH) problem. We reveal a previously unpublished flaw in the protocol and its proof, whereby we demonstrate that the protocol violates th...