A pairing-free certificate-based key-insulated aggregate signature scheme for wireless medical sensor networks

Wireless medical sensor networks (WMSNs) realize remote monitoring of patients' health status through the combination of medical sensors and wireless communication. There is an urgent need to ensure the integrity, authenticity, authentication, and privacy of patients' medical data and improve treatment outcomes. Currently, many aggregate signature schemes have been developed to protect patients' medical data in WMSNs. Among them, the pairing operation and key exposure in some aggregate signature schemes can raise efficiency and security issues in medical data transmission, and some of them do not achieve equivalent security, which leads to healthcare professionals receiving inaccurate medical data. Aiming at these, this paper proposes a pairing-free certificate-based key-insulated aggregate signature scheme (CB-KIAS) in WMSNs, which introduces key-insulated technique that can effectively avoid the problem of key exposure. According to formal security proof, this scheme is unforgeable against adaptive-chosen message attacks and having the equivalent security of aggregate signature to ensure that the validity of the aggregate signature is equal to the validities of all single signatures to resist fully chosen-key attacks. The proposed CB-KIAS scheme, utilizing elliptic curves and the combination of online/offline cryptography mechanism, is effective and more suitable for resource-constrained medical sensors when compared with other related schemes.