Research On Secure Sharing Of Electronic Medical Record Data Based On Blockchain And Proxy Re-encryption

Electronic Medical Records(EMR)store patients’ personal information as well as medical information such as examination symptoms,diagnosis,medication use and medical prescriptions.This information is valuable to medical institutions and other organizations,and its sharing can provide a source of data for prescribing,research data for research institutions,and reference and basis for doctors to develop personalized treatment plans.However,at present,EMRs are mostly held internally by hospitals,and the level of interoperability of medical information systems among major hospitals is low,resulting in the inability to share patients’ medical cards,which not only wastes medical resources but also increases the financial burden on patients and may even delay their treatment.Therefore,how to carry out EMR security sharing among medical institutions and even more related institutions is currently a hot spot for research in the field of intelligent medical care.At the same time,electronic medical records store patients’ personal privacy information,and patients also need to be informed about the use of EMR,so how to protect privacy and control the use of EMR in sharing is a research challenge.To address the above problems,this paper proposes a new research scheme for secure sharing of electronic medical record data,and the main work of this paper is as follows:(1)In response to the problems that the master nodes of Byzantine fault-tolerant consensus algorithm commonly used in current coalition chains are selected arbitrarily,there is no good response mechanism for node joining or withdrawing and the consensus efficiency decreases when there are more nodes,the dynamic-layering Reputation-evaluation and K-medoids Practical Byzantine Fault Tolerant(DRKPBFT)algorithm based on reputation and clustering is proposed.The algorithm first divides the nodes into K consensus regions by K-medoids algorithm,which improves the traditional PBFT into a polycentric,multi-level Byzantine algorithm and improves the efficiency when more nodes participate in consensus.Then the reliable consensus nodes with high reputation value are selected according to the reputation evaluation algorithm in it,and Byzantine nodes with low reputation value are eliminated,which improves the probability of reliable nodes being the main nodes,reduces the waste of resources in the consensus process,and can dynamically adjust the number of nodes when they join or exit,which makes it more promising for realizing electronic medical record data sharing.(2)In order to solve the problems associated with the sharing of electronic medical record data in reality,a unidirectional multi-hop identity proxy re-encryption scheme based on type and conditional(TC-UMH-IPRE)is proposed.Compared with other proxy re-encryption schemes,the proposed scheme not only achieves basic properties such as anti-complicity,non-interactive,and ciphertext fixed length,but also supports conditional control and dynamic switching of the type of encrypted information(sharable and non-sharable).This scheme can not only protect patients’ privacy in the process of secure sharing of electronic medical records,but also effectively avoid the huge computational overhead caused by repeated authorization of electronic medical records.(3)A research scheme for secure sharing of electronic medical record data based on federated chain with proxy re-encryption is proposed.The scheme firstly constructs a federated chain and interplanetary file system(IPFS),combined with hybrid storage EMR,i.e.,IPFS stores encrypted EMR,and the returned IPFS index value is stored in the federated chain,which can prevent thirdparty servers from tampering with data and reduce the storage pressure of the blockchain,realizing "on-chain storage of evidence,off-chain storage ".Secondly,the combination of one-way multihop identity proxy re-encryption based on type and conditions and Distributed Key Generation(DKG)technology designs a multi-center medical data sharing protocol,which ensures that only data requesters permitted by patients can access the EMR,not only protecting patient privacy,but also realizing fine-grained and flexible patient control over the EMR.control of the EMR.Finally,the data requestor is required to chain the EMR operation records,which enables the evidence tracing of EMR usage and further ensures that users are informed of their own electronic medical record usage.