A Lightweight Blockchain-Assisted Authentication and Key Agreement Protocol for Secure Internet of Medical Things

By leveraging the Internet of Things (IoT) network to enable real-time communication between doctors and patients, the Internet of Medical Things (IoMT) has significantly enhanced healthcare service delivery. Nevertheless, insecure communication channels expose IoMT systems to heightened energy consumption and potential data breaches. Although numerous authentication and key agreement protocols have been proposed to secure communication, many of them incur considerable computational and communication overhead on resource-constrained IoMT systems. Moreover, a substantial number of these protocols fail to effectively resist physical capture attacks and often lack scalability, which may result in excessive energy burdens in resource-limited scenarios. To address these challenges, we propose a lightweight blockchain-assisted authentication and key agreement protocol specifically designed for secure and resource-constrained IoMT systems. Considering the need for both scalability and low energy consumption in such systems, blockchain is employed to enable decentralized authentication managed by multiple gateway nodes. To further alleviate the risks arising from insecure communication, our protocol integrates a lightweight fuzzy extractor with physically unclonable functions, offering fault-tolerant authentication and hardware-level security assurances. Additionally, we introduce a dynamic pseudonym mechanism to guarantee identity anonymity and untraceability for both communicating parties during dynamic access sessions. Extensive security and performance evaluations demonstrate that the proposed protocol effectively withstands diverse attacks while maintaining lower computational and communication overhead compared with existing approaches.