A Password-Based Mutual Authenticated Key Exchange Scheme by Blockchain for WBAN

With the continuous development of Internet of Things technologies, Wireless Body Area Networks (WBAN) have shown great application potentials in the healthcare industry. However, adversaries may masquerade as legitimate users and sensitive medical data may be intercepted during transmission. Therefore, proper authentication and secure communications are required in WBAN. Password-based authenticated key exchange (PAKE) is an attractive solution for this problem due to its simplicity and low costs, i.e. the user and the server can use their shared password to perform authentication and to establish a session key for secure information exchange. However, many existing PAKE protocols are suffering some limitations. First, some schemes only consider one-way authentication, while masquerade is still possible on the server side. Second, some schemes are vulnerable to the offline dictionary attack, and the consequence is that the user’s password with limited entropy can be leaked. Third, some schemes need to employ secure channels, making them less practical in real-world applications. In this paper, we propose a password-based mutual authenticated key exchange scheme by Blockchain for WBAN, in which all these issues are addressed. In particular, mutual authentication is realized, and the adversary cannot launch the offline dictionary attack. Moreover, these features are achieved without employing a secure channel. Therefore, it achieves a good balance between usability and security. Security and performance analyses demonstrate that it satisfies the desirable security requirements and is very efficient for practical applications.