Revocable Attribute-Based Encryption with Efficient and Secure Verification in Smart Health Systems

By leveraging Internet of Things (IoT) technology, patients can utilize medical devices to upload their collected personal health records (PHRs) to the cloud for analytical processing or transmission to doctors, which embodies smart health systems and greatly enhances the efficiency and accessibility of healthcare management. However, the highly sensitive nature of PHRs necessitates efficient and secure transmission mechanisms. Revocable and verifiable attribute-based encryption (ABE) enables dynamic fine-grained access control and can verify the integrity of outsourced computation results via a verification tag. However, most existing schemes have two vital issues. First, in order to achieve the verifiable function, they need to execute the secret sharing operation twice during the encryption process, which significantly increases the computational overhead. Second, during the revocation operation, the verification tag is not updated simultaneously, so revoked users can infer plaintext through the unchanged tag. To address these challenges, we propose a revocable ABE scheme with efficient and secure verification, which not only reduces local computational load by optimizing the encryption algorithm and outsourcing complex operations to the cloud server, but also updates the tag when revocation operation occurs. We present a rigorous security analysis of our proposed scheme, and show that the verification tag retains its verifiability even after being dynamically updated. Experimental results demonstrate that local encryption and decryption costs are stable and low, which fully meets the real-time and security requirements of smart health systems.