Efficient three‐party encrypted key exchange using trapdoor functions

Abstract

Three‐party encrypted key exchange (3PEKE) enables two communicating parties to securely exchange confidential and authenticated information over an insecure network via a trusted server. This investigation presents a novel efficient and secure 3PEKE protocol using a super‐poly‐to‐one trapdoor function. The proposed protocol employs the Diffie–Hellman key exchange and adopts the technique that the clients can publicly exchange the factors for generating the session key without the help of the server to reduce the numbers of transmissions. A round‐efficient version of the proposed 3PEKE protocol is also described. Compared with related approaches, the proposed protocol not only retains security requirements and possesses lower computational cost but also has fewer transmissions and realizes the lower bounds of communications. Copyright © 2013 John Wiley & Sons, Ltd.

Two-Round Password-Only Authenticated Key Exchange in the Three-Party Setting

“…• The recent protocol of Tsai and Chang [30] can run in two rounds (without key confirmation), but this protocol only works in a hybrid setting that requires both a cryptographic key and a password pre-established between each client and the server (see [4,29,[36][37][38][39][40][41][42][43][44] for other protocols designed to work in a hybrid setting). Table 1 summarizes the security properties and known weaknesses of published two-round three-party PAKE protocols with (claimed) proofs of security.…”

Cryptanalysis and improvement of a three‐party password‐based authenticated key exchange protocol with user anonymity using extended chaotic maps

“…Because each client needs to remember a separate password for each partner, for a large number of clients, it may overweigh the storage capacity of the clients. To avoid this problem, PAKE protocols have been developed for setting between three parties (in short, 3PAKE) . In a 3PAKE protocol, a trusted server mediates between two communication clients, and each client only has to share a memorable password with the server.…”

“…Generally, there are two main approaches to protect 3PAKE protocols against dictionary attacks. The first approach is to use either server's public key or symmetric cryptosystems, or a combination of both (e.g., ), and the second approach is without using server's public key or symmetric cryptosystems (e.g., ). Using server's public key and symmetric cryptosystems requires to construct a key management mechanism and constrain more complexity and computational cost to the protocol.…”