Secure Cross-domain Medical Data Sharing based on Distributed Cloud and Blockchain Services

Electronic Health Record (EHR) provides critical medical data. Sharing EHRs can add services and value for hospitals and patients and effectively improve medical services’ quality. In the process of cross-hospital diagnosis, EHRs cannot be shared across domains because they are separately stored in various hospitals, which may prevent timely diagnosis and lead to data isolation in medical data. Insecure storage and sharing also endanger the privacy of patients’ data, which likely leads to the disclosure of privacy-sensitive information or unauthorized access. To address these challenges, we propose a secure, cross-domain medical data-sharing scheme with data confidence protection. Specifically, we use a distributed cloud to realize cross-domain sharing of medical data, addressing the data isolation caused by the difference in hospital geographical locations. We combine a symmetric encryption algorithm with attribute encryption based on ciphertext policy (CP-ABE) to ensure the confidentiality and privacy of shared data, delivering fine-grained access control of shared medical data. Further, we introduce a key blockchain to store the ciphertext of the decryption key, the storage index of the data ciphertext, and store the ciphertext of the original data off-blockchain. Experiments show that the proposed scheme can perform better than existing cloud server-based data-sharing schemes.