Abstract. In this paper we introduce very simple deterministic randomness extractors for Diffie-Hellman distributions. More specifically we show that the k most significant bits or the k least significant bits of a random element in a subgroup of Zp are indistinguishable from a random bit-string of the same length. This allows us to show that under the Decisional Diffie-Hellman assumption we ca...

This paper addresses an interesting security problem in wireless ad hoc networks: the Dynamic Group Key Agreement key establishment. For secure group communication in an Ad hoc network, a group key shared by all group members is required. This group key should be updated when there are membership changes (when the new member joins or current member leaves) in the group. In this paper, We propos...

Oblivious transfer (OT) is a basic building block in many cryptographic protocols. In this paper, we exploit some well-known authenticated Diffie-Hellman-based key exchange protocols to build three authenticated 1-out-of-2 oblivious transfers. We show that our proposed protocols are secure in the semi-honest model. We also compare our schemes with three similar 1-out-of-2 OT protocols and show ...

This paper studies various computational and decisional DiffieHellman problems by providing reductions among them in the high granularity setting. We show that all three variations of computational DiffieHellman problem: square Diffie-Hellman problem, inverse Diffie-Hellman problem and divisible Diffie-Hellman problem, are equivalent with optimal reduction. Also, we are considering variations o...

In response to the need for secure one-round authenticated key exchange protocols providing both perfect forward secrecy and full deniability, we put forward a new paradigm for constructing protocols from a Diffie-Hellman type protocol plus a non-interactive designated verifier proof of knowledge (DV-PoK) scheme. We define the notion of DV-PoK which is a variant of non-interactive zero-knowledg...

A generalization of the original Diffie-Hellman key exchange in (Z/pZ) found a new depth when Miller [27] and Koblitz [16] suggested that such a protocol could be used with the group over an elliptic curve. In this paper, we propose a further vast generalization where abelian semigroups act on finite sets. We define a Diffie-Hellman key exchange in this setting and we illustrate how to build in...

Dynamic group Diffie-Hellman protocols for Authenticated Key Exchange (AKE) are designed to work in a scenario in which the group membership is not known in advance but where parties may join and may also leave the multicast group at any given time. While several schemes have been proposed to deal with this scenario no formal treatment for this cryptographic problem has ever been suggested. In ...

A generalization of the original Diffie-Hellman key exchange in (Z/pZ) found a new depth when Miller [27] and Koblitz [16] suggested that such a protocol could be used with the group over an elliptic curve. In this paper, we propose a further vast generalization where abelian semigroups act on finite sets. We define a Diffie-Hellman key exchange in this setting and we illustrate how to build in...