Improved Authenticated Key Agreement Scheme for Fog-Driven IoT Healthcare System

The Internet of things (IoT) has been widely used for various applications including medical and transportation systems, among others. Smart medical systems have become the most effective and practical solutions to provide users with low-cost, noninvasive, and long-term continuous health monitoring. Recently, Jia et al. proposed an authentication and key agreement scheme for smart medical systems based on fog computing and indicated that it is safe and can withstand a variety of known attacks. Nevertheless, we found that it consists of several flaws, including known session-specific temporary information attacks and lack of per-verification. The opponent can readily recover the session key and user identity. In this paper, we propose a secure authentication and key agreement scheme, which compensates for the imperfections of the previously proposed. For a security evaluation of the proposed authentication scheme, informal security analysis and the Burrows–Abadi–Needham (BAN) logic analysis are implemented. In addition, the ProVerif tool is used to normalize the security verification of the scheme. Finally, the performance comparisons with the former schemes show that the proposed scheme is more applicable and secure.