EMRShareChain: A Privacy-Preserving EMR Sharing System Model Based on the Consortium Blockchain

Electronic medical record (EMR) Sharing can reduce duplicate medical tests, reduce treatment costs and improve the quality of medical services. However, most medical organizations currently use the internal network to track patients but don't implement data sharing with other medical organizations. Meanwhile, the EMR is also highly vulnerable to theft and tampering by malicious attackers. To solve the above problems, we design a privacy-preserving EMR sharing system model based on consortium blockchain, called EMRShareChain. In EMRShareChain, multiple medical organizations firstly spontaneously build up a medical consortium. The EMR generated by a patient's treatment at a medical organization is encrypted and stored securely in the cloud, and the index of the EMR is stored in the blockchain. With the above storage method, not only the risk of EMR leakage is reduced, but also the EMR cannot be tampered with arbitrarily. Then, other organizations in the medical consortium can find the patient's relevant EMR in the blockchain by keywords in the index and keyword searchable encryption, and obtain the EMR key and EMR storage address generated by the conditional proxy re-encryption after the patient's authorization to achieve access to the EMR and data sharing. In addition, an improved PBFT consensus algorithm (I-PBFT) based on comprehensive scoring mechanism is proposed to improve the blockchain block-out efficiency and stability, making it more suitable for medical scenarios. Finally, a prototype implementation of the above model is carried out based on the Hyperledger Fabric framework. The Hyperledger fabric chaincode is accessible at https://github.com/xl13455/EMRShareChain and code can be downloaded.