Research And Implementation Of Electronic Health Records System Based On Hyperledger Fabric And Cloud Storage

The informationization construction in the medical field has gradually entered a new stage with the development and popularization of the Internet.The EHR electronic health records stores,manages and transmits patient's medical records and history of medical treatment by using electronic information technology.Under the traditional medical model,EHR is stored in the centralized database of medical institutions using plaintext,which not only has the possibility of leaking medical records,but also reduces the liquidity and shareability of medical records between patients,hospitals and medical data companies.Compared with the existing blockchain medical projects,this system has the advantages of fast access,large medical record storage and medical records privacy protection.This thesis uses Hyperledger Fabric as the underlying architecture support for client applications,and adopts cloud storage technology to deeply study the functions of storage and transmission of medical records in electronic medical records system,transaction and privacy protection,and key technologies in it.And to develop the electronic medical records client program and smart contract development,research and explore the application of blockchain in the medical field.In-depth study of the EHR system business scenario,design the EHR system architecture model and divide the functional modules.Firstly,according to the responsibilities of patients,medical institutions and enterprises,the organizational structure of the EHR system in the blockchain network is designed and the specific tasks and operations of each node in the transaction endorsement process are analyzed.Then the EHR system architecture is given according to this,and the client is provided.The program is divided into four modules: login,encryption and decryption,Chaincode interface and transmission program.Finally,the functional modules of EHR system are introduced.In-depth research and implementation of the medical storing in chain and transmission,medical records privacy protection and trading functions,while the transmission efficiency and storage efficiency of medical records were optimized.Through the research on the medical file Storing in blockchain and transmission,this thesis proposes to store the medical file index information in the blockchain account and build the HDFS storage medical records file between the cloud servers.The index information is defined as the Records structure,which contains information such as the digital summary of the medical records file and the cloud storage path.In the process of medical records transmission,in order to improve the transmission efficiency and effectively utilize the storage capacity of Data Node block,this thesis adopts the scheme of small file segmentation,large file merging and combined with breakpoint continuous transmission technology.By using offset offset to give the breakpoint retransmission implementation process,at the same time,the client program is written to realize small file merging,large file blocking function and test comparison of the optimized program transfer rate and block block storage usage.Seven representative medical records were selected and divided into two groups for testing.The average transmission rate after file consolidation was increased by 4.52% and 8.65%,respectively.Compared with the IO request between the OS and the hard disk management system before optimization.In the process of strengthening patient's medical records privacy protection and realizing medical records transaction and access,firstly,the research on the possible leakage of privacy is carried out.The thesis summarizes and proposes to encrypt the medical records file using AES symmetric encryption algorithm and encrypt the AES with RSA asymmetric encryption algorithm public key.The key scheme,the AESEncryptor and RSAEncryptor classes are written to realize the encryption and decryption function of the medical records file and the AES key;then the smart contract development and transaction endorsement process is deeply studied,and the basic operation interface of the smart contract access Records is defined,including initialization.Patient's medical records,specified patient medical records query,patient's medical records transaction and patient medical records deletion interface;then configure the blockchain network,generate the initial block,generate CA certificate,create organization and channel,start Peer and Orderer node and deploy Smart contracts,etc.;finally,by writing the Invoke CC class to call the Chaincode API,the Transaction transaction entity class records transaction status information,and the Account class records account related information,etc.,to implement the business process of the client medical records transaction and access function.