Research On Big Health Data Storage And Sharing Scheme Based On Blockchain

In daily life,the importance of health for human beings is self-evident.Health data has the characteristics of variety,large quantity and strong privacy.In the current system,organizations hold health data generated by their own users,and data is not shared between organizations,leading to the problem of data silos.It is a very challenging problem to solve the mutual trust among organizations and realize the safe and efficient sharing of health data while ensuring user privacy and data security.In view of the above problems,this thesis collectively refers to daily health data,sports health data and medical health data as big health data.Taking big health as the research scenario,a blockchain-based big health data storage and sharing model is proposed to realize the safe storage and sharing of residents’ health data.This thesis mainly includes the following aspects of research:（1）A blockchain based big health data storage and sharing model is proposed.The health data is encrypted and stored in the corresponding server,and the hash summary and storage location of the data are stored in each node consortium chain;The access records generated by cross domain data sharing between heterogeneous networks are uniformly stored in the big health consortium chain.The model ensures the security,integrity and consistency of data in the process of storage and sharing.（2）Due to the large number of nodes involved in the research scenario in this thesis,the Practical Byzantine Fault Tolerance（PBFT）algorithm is not fully applicable to the research scenario in this thesis.In order to reduce the probability of dishonest nodes serving as master nodes,improve the consensus efficiency of consensus nodes and the fault-tolerance rate of nodes in the blockchain network,Node Credit Practical Byzantine Fault Tolerance（NCPBFT）is proposed in this thesis.The credibility of nodes is calculated from two dimensions of direct credit and recommendation credit,and the credit threshold is set.By classifying nodes and grouping by consensus,the fault-tolerant rate and consensus efficiency of each network are improved,which makes the model suitable for the scenario studied in this thesis.（3）A cross-domain data sharing scheme based on block chain is proposed to avoid problems such as user private key disclosure and association of different health data in the process of cross-domain sharing of big health data and improve the efficiency of data sharing.Unidirectional multi-hop re-encryption technology is used to ensure the integrity and privacy of data in the process of cross-domain sharing.By using this encryption technology,the node can re-encrypt the data after re-encryption,satisfying the situation of multiple users accessing the same data successively.（4）The access control mechanism based on block chain and edge computing is proposed to solve the problems such as opaque data access flow process,untraceable access flow and multiple access with one authorization.The smart contract technology is used to transform the customized custom attribute-based access control policy of data into the form of smart contract,so as to control the access of data users more intelligently.By introducing edge computing,edge nodes perform decryption operation,which saves computing power consumption of blockchain nodes and reduces sharing delay.Finally,the internal data sharing records of the network are stored in the log blockchain,and the cross domain data sharing records are stored in the grand Health Alliance.The blockchain technology is used to ensure that the access records are traceable and tamper proof.Data sharing records are stored in the log blockchain to ensure that access records are traceable and tamper-proof.