Search

We describe a mechanical approach to derive identity-based (ID-based) protocols from existing Diffie–Hellman-based ones. As case studies, we present the ID-based versions of the Unified Model protocol, UMP-ID, Blake-Wilson et al. (1997)’s protocol, BJM-ID, and Krawczyk (2005)’s HMQV protocol, HMQV-ID. We describe the calculations required to be modified in existing proofs. We conclude with a comparative security and efficiency of the three proposed ID-based protocols (relative to other similar published protocols) and demonstrate that our proposed ID-based protocols are computationally efficient. [ABSTRACT FROM AUTHOR]

Abstract: In TCC ’07, Abdalla et al. presented a protocol compiler that transforms any authenticated 2-party key exchange protocol into an authenticated group key exchange (GKE) protocol. Abdalla et al.’s compiler is certainly elegant in its genericness, symmetry, simplicity and efficiency. However, this compiler is not as secure as claimed. Under a reasonable assumption, the GKE protocol constructed by the compiler (from a 2-party protocol) fails to achieve implicit key authentication. We here reveal this security problem with the compiler and show how to address it. [Copyright &y& Elsevier]

Abstract: Protocols for group key exchange are cryptographic algorithms that describe how a group of parties communicating over a public network can come up with a common secret key. Due to their critical role in building secure multicast channels, a number of group key exchange protocols have been proposed over the years in a variety of settings. However despite many impressive achievements, there seems to have been no previous systematic look at the growing problem of key exchange over integrated wired and wireless (IWW) networks which consist of two distinct types of users: users having low-performance mobile devices with some form of battery power and users having high-performance stationary computers with no power constraint. The contribution of the present work is to fill this deficiency by providing a secure and efficient protocol for resource-aware group key exchange over the rapidly expanding IWW networks. By evenly spreading much of the total amount of computation across high power users, our protocol avoids any potential performance bottleneck of the system while keeping the burden on low power users at minimal. Our protocol also achieves provable security against powerful active adversaries under the decisional Diffie–Hellman assumption. We provide a rigorous proof of security for the protocol in a well-defined formal model of communication and adversarial capabilities. [Copyright &y& Elsevier]

Abstract: Authentication and key exchange are fundamental for establishing secure communication channels over public insecure networks. Password-based protocols for authenticated key exchange are designed to work even when user authentication is done via the use of passwords drawn from a small known set of values. Recently, Wen et al. (H.-A. Wen, T.-F. Lee, T. Hwang, Provably secure three-party password-based authenticated key exchange protocol using Weil pairing, IEE Proceedings—Communications 152 (2) (2005) 138–143) proposed a new protocol for password-based authenticated key exchange in the three-party setting, where the clients trying to establish a common secret key do not share a password between themselves but only with a trusted server. Wen et al.’s protocol carries a claimed proof of security in a formal model of communication and adversarial capabilities. However, this work shows that the protocol for three-party key exchange is completely insecure and the claim of provable security is seriously incorrect. We conduct a detailed analysis of flaws in the protocol and its security proof, in the hope that no similar mistakes are made in the future. [Copyright &y& Elsevier]