BC-PC-Share: Blockchain-Based Patient-Centric Data Sharing Scheme for PHRs in Cloud Computing

Sharing of personal health records (PHR) in cloud computing is an essential functionality in the healthcare system. However, how to securely, efficiently and flexibly share PHRs data of the patient in a multi-receiver setting has not been well addressed. For instance, since the trust domain of the cloud server is not identical to the data owner or data user, the semi-trust cloud service provider may intentionally destroy or tamper shared PHRs data of user or only transform partial ciphertext of the shared PHRs or even return wrong computation results to save its storage and computation resource, to pursue maximum economic interest or other malicious purposes. Thus, the PHRs data storing or sharing via the cloud server should be performed with consistency and integrity verification. Fortunately, the emergence of blockchain technology provides new ideas and prospects for ensuring the consistency and integrity of shared PHRs data. To this end, in this work, we leverage the consortium blockchain technology to enhance the trustworthiness of each participant and propose a blockchain-based patient-centric data sharing scheme for PHRs in cloud computing (BC-PC-Share). Different from the state-of-art schemes, our proposal can achieve the following desired properties: (1) Realizing patient-centric PHRs sharing with a public verification function, i.e., which can ensure that the returned shared data is consistent with the requested shared data and the integrity of the shared data is not compromised. (2) Supporting scalable and fine-grained access control and sharing of PHRs data with multiple domain users, such as hospitals, medical research institutes, and medical insurance companies. (3) Achieving efficient user decryption by leveraging the transformation key technique and efficient user revocation by introducing time-controlled access. The security analysis and simulation experiment demonstrate that the proposed BC-PC-Share scheme is a feasible and promising solution for PHRs data sharing via consortium blockchain.