Efficient Certificateless Online/Offline Signature Scheme for Wireless Body Area Networks

Wireless body area networks (WBANs) have become more commonplace, including in healthcare settings. For example, in a healthcare WBAN deployment, body sensor units (BSUs) are used to sense and collect health-related and medical-related information prior to sending relevant information to the server for analysis that can subsequently inform treatment plan. Given the sensitivity of both data-at-rest and data-in-transit, data authentication is fundamental to the success of such systems. However, BSUs are generally resource constrained and, hence, conventional cryptographic algorithms are not practical. Therefore, in this article, we propose an efficient certificateless online/offline signature scheme and design a lightweight data authentication protocol for WBANs. We then evaluate the security and performance of our proposed scheme, where the security analysis demonstrates that the proposed scheme satisfies existential unforgeability under the random oracle model. Findings from the performance evaluation also demonstrate that our scheme incurs very low computational cost during the signing operations. In comparison to several other competing approaches, our proposed scheme achieves a significant reduction in computational cost (up to 89%) for the offline signer and supports batch verification to reduce the verifier's execution time. In addition, we also show that the signature size of our proposed scheme is similar to those of the conventional signature schemes.