A robust remote user authentication scheme resistant to known session specific temporary information attack

Rapid growth of mobile and networking technologies, resulted in new paradigms of networking like Internet of Things (IoT) etc, which allows user to connect to insecure public communication channel through various devices and can access the services and data provided by remote server. Thus, remote user authentication and key agreement for wireless, wired, IoT communications becoming more challenging task. In this context many researchers have proposed authentication schemes. In 2013, An et al. proposed a dynamic ID-based remote user authentication scheme which is secure, even if the secret values stored in the smart card is revealed. In 2014, Troung et al claimed that An et al scheme is vulnerable to server forgery attack and proposed an improved scheme. In this manuscript, we validate that Troung et al's scheme is vulnerable to known session specific temporary information attack, replay and impersonation attack. Furthermore, we also propose the improved scheme to overcome these limitations without increase in the cost front.