Enhancing Healthcare Data Security Using PQ-ABE and Verifiable Secret Sharing Schemes

At present, the lack of data exchange and sharing between different hospitals leads to the formation of data silos. Additionally, regional healthcare data contain a significant amount of sensitive patient information, and the public access, sharing, and circulation of this data can result in malicious tampering, theft, misuse, and loss of ownership, ultimately compromising patient privacy. Due to the massive volume and unstructured nature of medical data, it becomes more challenging to defend against and trace targeted malicious attacks, such as data theft, tampering, and ransomware attacks. To address these issues, this paper proposes a blockchain-based electronic health record (EHR) sharing scheme with multi-level access control to ensure secure and privacy-preserving data sharing. The proposed scheme incorporates Post-Quantum Attribute-Based Encryption (PQ-ABE) to handle attribute management across decentralized authorities while resisting collusion attacks among users with different permissions. Additionally, Verifiable Secret Sharing is utilized to protect attribute privacy by splitting attributes into attribute names and attribute values, ensuring confidentiality. This paper creates an access policy update algorithm that adds policy blocks across a blockchain to generate a trackable record of policy changes using blockchain transparency, immutability, and audibility features. This approach enables distributed and trustworthy access control management under concealed policy conditions, ensuring data privacy protection and traceability of user actions. Security analysis and experimental results demonstrate that the proposed scheme effectively protects attribute privacy while reducing computational overhead.