In this survey, we describe a general key exchange protocol based on semidirect product of (semi)groups (more specifically, on extensions of (semi)groups by automorphisms), and then focus on practical instances of this general idea. This protocol can be based on any group or semigroup, in particular on any non-commutative group. One of its special cases is the standard Diffie-Hellman protocol, ...

Dragon y is a password authenticated key exchange protocol that has been submitted to the Internet Engineering Task Force as a candidate standard for general internet use. We analyzed the security of this protocol and devised an attack that is capable of extracting both the session key and password from an honest party. This attack was then implemented and experiments were performed to determin...

Group key exchange (GKE) protocols can be used to guarantee confidentiality and group authentication in a variety of group applications. The notion of provable security subsumes the existence of an abstract formalization (security model) that considers the environment of the protocol and identifies its security goals. The first security model for GKE protocols was proposed by Bresson, Chevassut...

Recently, Tseng and Wu pointed out that the second protocol of Biswas’s two-party keys scheme based on the Diffie-Hellman technique has a security weakness and proposed a new protocol to remedy the weakness. In this article, we point out that Tseng-Wu’s protocol is vulnerable to a man-in-the-middle attack. An attacker could intercept, delete, or modify the communicated messages between two comm...

Cryptographic key exchange is considered to be a challenging problem in Delay Tolerant Networks (DTNs) operating in deep space environments. The difficulties and challenges are attributed to the peculiarities and constraints of the harsh communication conditions DTNs typically operate in, rather than the actual features of the underlying key management cryptographic protocols and solutions. In ...

In this paper we show that the password-based Diffie-Hellman key exchange protocols due to Byun and Lee suffer from dictionary attacks.

Key exchange is considered to be a challenging problem in Delay Tolerant Networks (DTNs) operating in space environments. In this paper we investigate the options for integrating key exchange protocols with the Bundle Protocol. We demonstrate this by using a one-pass key establishment protocol. In doing so, we also highlight the peculiarities, issues and opportunities a DTN network maintains, w...

In mathematics,spciticially in abstract algebra and its applications, discrete loga-rithms are group -theoretic analogues of ordinary logarithms. The problem of computing both problems are difficult, alogrithms from one problem are often adapted to the other, and the difficulty of both problems has been exploited to construct various cryptographic system. This work describes an application of t...

We present a password-authenticated group key exchange protocol where each user has his/her own password. Advantage of such protocol is in short passwords, which can be easily memorized. On the other hand these protocols face the low password entropy. In the first part we define security model based on models of Abdalla, Fouque and Pointcheval and Bellare, Pointcheval, Rogaway. We construct the...

Dragonfly is a password authenticated key exchange protocol that has been submitted to the Internet Engineering Task Force as a candidate standard for general internet use. We analyzed the security of this protocol and devised an attack that is capable of extracting both the session key and password from an honest party. This attack was then implemented and experiments were performed to determi...