MD-S³C³: A Medical Data Secure Sharing Scheme With Cloud and Chain Cooperation

In medical data sharing, the data access control authorities of the sharing entities and computing capabilities of the sharing platforms are asymmetric. This asymmetry leads to poor patient control over their data, privacy disclosure, and difficulties in tracking data sharing. This aarticle proposes a cooperation model of cloud and chain (CMCC) for the secure sharing of medical data. In the CMCC, the power equivalence of blockchain nodes limits the control authority asymmetry between doctors and patients in medical data sharing. Moreover, a cloud server is used to store medical data, and some of the node-side computations are handed over to the cloud, which addresses the asymmetric computing capability asymmetry between the cloud and ordinary nodes. Based on the CMCC, a secure medical data sharing scheme based on proxy re-encryption mechanism is proposed. This scheme realizes secure medical data sharing, especially the patient's complete control of the data. The security and performance analysis show that the proposed scheme outperforms the existing ones.