Cryptanalysis of Chaos-Based 2-Party Key Agreement Protocol with Provable Security

Abstract

In a public communication environment, a remote user authentication scheme for establishing a secure session between a user and a server is a very important factor. Authentication schemes, which originate from a password-based authentication scheme, apply some mathematical algorithms to securely share session keys between users and servers. In a remote user authentication scheme, safety is a very important factor, but it is also important to reduce computational cost. Therefore, even if a mathematical algorithm is applied, it is necessary to select an algorithm that consumes a small amount of computation. Recently, Luo et al. proposed a chaos-based two-party key exchange protocol and claimed that the proposed scheme solved the off-line password guessing attack and was safe from other common attacks. They used a Chebyshev chaotic maps. This algorithm is used in many authentication schemes because it consumes a small amount of computation. However, we find that Luo et al.’s scheme is still insecure. In this paper, we show the problems of Chebyshev chaotic maps and demonstrate how an attacker can attempt some attacks.