Blockchain-based EHR Privacy Preserving And Sharing Scheme

With the development of information and network technologies,an increasingly large volume of data has been generated and collected.And data provides important support for quantitative progress in the national economy,life and military affairs.And it can be said that data has penetrated into all aspects of our lives.While enjoying the convenience of data resources,we are also exposed to the risk of privacy leakage.The exposure of personal information may not only cause financial risk,but it may endanger personal life in serious cases.The Electronic Health Record(EHR),as a scientific record of the residents' health management(disease control,health protection,health promotion,etc)process,stores a large amount of personal sensitive information.Thus its safety protection cannot be ignored.At present,access control is the core of data privacy and security protection.Blockchain is a distributed architecture.The information recorded on the ledger is publicly verifiable and cannot be modified,providing a new solution for privacy protection and data sharing.The idea is now an extremely hot research direction.This article proposes a blockchain-based privacy preserving and sharing scheme for medical information.In view of information fragmentation and misalignment of information ownership in the existing EHR management system,the characteristic of openness and tamper-resistance of blockchain ledger and user-defined access policy are used to realize the data owner's control and other's secure access to data.Aiming at the problem of consensus efficiency in blockchain,an advanced Po S consensus algorithm improves the synchronization speed of the ledgers and enhances the sharing efficiency.Finally,a systematic analysis of security and efficiency of the blockchain-based medical information storage and sharing system is conducted.The results show that the blockchain-based information storage and sharing system solves the problem of user information fragmentation storage,and achieves cross-institutional sharing of EHR,having advantages of safety and efficiency.This article proposes an authoritative time distribution and synchronization scheme based on blockchain.Based on the analysis of traditional time synchronization protocol,this paper designs a time synchronization system based on blockchain,which solves the problems of low error-tolerance rate and low synchronization efficiency of the original system.The method that time synchronization party actively requests is utilized to reduce the overhead of consensus nodes.Finally,the results of analyzing and simulating reflects this scheme can resist the attacks of malicious nodes to the time nodes,which has advantages of security and high efficiency.This article focuses on blockchain-based privacy preserving and sharing schemes.It mainly proposes privacy protection and sharing schemes for medical information and authoritative time distribution and synchronization schemes.Using the distributed architecture of blockchain and its open and non-derogable nature of blockchain ledger,valuable information is recorded on ledger.The former solution addresses the problems of distribution of medical information fragmentation,misplaced user ownership of information,and fine-grained access to information.The latter solution is to achieve the distribution and synchronization of authoritative time,solving the problem of proliferation of forgery time information in the Internet of Things,and abnormal collaboration caused by different node time.