Research On Access Control And Security Sharing Of Electronic Health Records Based On Blockchain

With the continuous development of science and technology and the support of policies aimed at promoting economic development,medical data has explored more application scenarios in terms of accessing and sharing,and is gradually becoming digitalized.However,although the combination of electronic health records(EHR)and blockchain has led to the proper use of their advantages,if users cannot use the data in the blockchain network reasonably and legally,it will directly threaten the privacy and integrity of the data,and even affect the performance of the whole system.In addition,the data in the blockchain cannot be interoperable and cannot be shared to the maximum extent in different business areas,thus causing the problem of data silos.To address the above problems,this paper takes blockchain as the basic application platform and electronic health record as the data interaction carrier for research and analysis.With the support and introduction of technologies such as smart contracts and cross-chain services,the blockchain system is prompted to have strong scalability and efficient data management level,and the encryption technology and consensus mechanism in the blockchain network guarantee the security of data in the sharing process and the orderly processing of transactions.The specific work of this thesis is shown as follows:First,a PBFT(Practical Byzantine Fault Tolerance,PBFT)based POS(Proof of Stake,POS)hybrid consensus optimization for secure data sharing scheme is proposed.The combined consensus process of PBFT and POS,combined with a decentralized verifiable cryptographic election algorithm,is investigated to optimize the consensus election and synchronization process.The scheme provides the low latency and high throughput features of PBFT mechanism for blockchain networks and enables a large number of nodes in the system to participate in the whole consensus process in a fair and dynamic manner.A comparison test of the optimization algorithm in terms of latency and throughput shows that the optimization algorithm has excellent characteristics such as low latency and high throughput.Second,a smart contract-based data security sharing scheme is designed and implemented.The scheme provides an effective innovation point: under the AI(Artificial Intelligence,AI)-enabled blockchain model,the smart contract is further intelligent,avoiding the disadvantages of smart contract condition-driven,providing powerful analysis and decision making and vulnerability prediction for the data in the blockchain network,and guaranteeing the secure data sharing.By building the corresponding smart contracts,the data trust problem in the blockchain network and the single point of failure and privacy problems brought by its centralized authorization are solved.Finally,the performance analysis of smart contracts and AI-driven intelligent contracts shows that the AI-driven intelligent contracts possess excellent performance that is much higher than that of ordinary smart contracts.Third,a data access control scheme based on cross-chain technology and edge computing is designed.The scheme proposes a data access control model based on Hyperledger Fabric as a platform,which uses edge computing nodes to manage data and combines CP-ABE(Ciphertext policy attribute based encryption,CP-ABE)and XACML(e Xtensible Access Control Markup Language(XACML)provides flexible and stable encryption protection and fine-grained access control for data,and introduces hybrid cross-chain technology to achieve strong scalability of the model.Finally,experimental tests on system performance and scalability of the model show that the model has good operational stability and high data processing performance,and can provide reasonable record and permission control when users access EHR(Electronic Health Records,EHR)data.