Cryptanalysis and Improvement of an ´Efficient Remote Mutual Authentication and Key Agreement´

A smart card based scheme is practical and widely used in remote mutual authentication. In 2006, Shieh-Wang pointed out the weakness of Juangpsilas remote mutual authentication scheme using smart card and further proposed a novel one to improve Juangpsilas. The advantages in Shieh-Wangpsilas scheme include effective mutual authentication, freely chosen password, no verification tables, low computational cost, session key agreement and no synchronized clocks. However, in 2007, Yoon-Yoo showed that Shieh-Wangpsilas scheme does not provide perfect forward secrecy, and is vulnerable to a privileged insiderpsilas attack. Furthermore, the current paper demonstrates that Shieh-Wangpsilas scheme is also vulnerable to the parallel session attack and lack of wrong password detection and then presents a more efficient and secure scheme to resolve all the above problems including those that Yoon-Yoo has pointed out with less computational cost increase.