A Physician's Privacy-Preserving Authentication and Key Agreement Protocol Based on Decentralized Identity for Medical Data Sharing in IoMT

As well known, Internet of Medical Things (IoMT) produces large amounts of medical data and promotes the medical data sharing which serves the data user (i.e., physicians) to boost the clinical treatment and medical research. To protect data user's privacy and data security during the sharing of medical data, the data user must have a self-sovereign decentralized identity (DID) and data access authority. In existing solutions, data user's privacy protection and authentication-key-agreement (AKA) for protecting data security are worked independently, which easily results in typical security attacks (e.g., phishing inquiry attacks and ephemeral secret leakage attacks) during data access and system computing overload. To solve the challenge, a new credential-embedded AKA (CAKA) scheme is proposed, which can seamlessly combine DID-credentials into AKA. First, CAKA supports bilateral authentication by allowing a digital user to authenticate its service provider, which can enhance the security of unilateral scheme (such as CanDID, IEEE S&P, 2021) and prevent phishing query attacks. Second, for secure data session communication, the user's DID-credentials are used as the kernel of the session key (SK) generation. In security analysis and performance metrics comparisons, the results indicate that CAKA holds a significant advantage, especially, the storage costs, communication costs, and computation costs consumed in CAKA are at least 43% reduction, compared to the alternatives. In simulation experiments of CAKA, the results show that DID authentication and SK agreement are both less than 15 ms, that means CAKA is a practical and promising solution to medical data sharing.