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

Summary Three‐party password‐authenticated key exchange (3PAKE) protocols allow two clients to agree on a secret session key through a server via a public channel. 3PAKE protocols have been designed using different arithmetic aspects including chaotic maps. Recently, Lee et al. proposed a 3PAKE protocol using Chebyshev chaotic maps and claimed that their protocol has low computation and communication cost and can also resist against numerous attacks. However, this paper shows that in spite of the computation and communication efficiency of the Lee et al. protocol, it is not secure against the modification attack. To conquer this security weakness, we propose a simple countermeasure, which maintains the computation and communication efficiency of the Lee et al. protocol. Copyright © 2014 John Wiley & Sons, Ltd.