Research On Blockchain-based Medical Data Storage And Sharing Scheme

With the explosive growth of medical data,smart medical care plays an increasingly important role in people’s lives.The safe storage and sharing of medical data is the key to improving the quality of medical services.The development of cloud-assisted electronic medical system effectively solves the shortcomings of traditional medical management systems.However,there are still some challenging issues.First,it is difficult to ensure the integrity of the electronic health record(EHR)during the data outsourcing process.Secondly,it is difficult to ensure the privacy and traceability of electronic medical records during the data sharing process.Finally,there is a big contradiction between access control and data sharing.On the one hand,in view of the sensitivity and confidentiality,the protection of medical data is retained.Strict access control will inevitably lead to inefficient data sharing,which is not conducive for research institutions to obtain medical value from available data sets;on the other hand,in view of the volatility of data value,reduce access control efforts to achieve good data sharing,Inevitably accompanied by data abuse and privacy leakage.In this thesis,a blockchain-based e Health system called BCES is proposed to ensure that the manipulation of EHRs can be audited.In BCES,each legitimate query manipulation of data consumers,together with each legitimate outsourcing manipulation of hospitals,will be written into the blockchain as a transaction for permanent storage,which ensures the traceability.At the same time,the attributes-based proxy re-encryption is adopted to achieve fine-grained access control of medical data,and any behavior that threatens the integrity of EHRs will be discovered by the auditor.Due to the traceable and tamper-resistant characteristic of blockchain,any entity that had an illegal manipulation of EHRs will be held accountable to the evidence of our constructed Proof-Chain.Specifically,the contributions of this thesis are as follows:1)Aiming at the drawbacks of existing medical systems,we designed a novel and efficient blockchain-based e Health system-BCES.In this scheme,the characteristics of the blockchain are fully utilized to ensure that all kinds of users’ manipulation logs of EHRs are traceable and transparent.Moreover,the structure of the Proof-Chain retains a reasonable channel of accountability for vulnerable patient groups.2)Flexible access control strategies are designed for the secure sharing of EHR.The introduction of attributes allows users to customize the authorization group,and the introduction of proxy nodes allows patients to successfully complete data authorization without requiring large computing power.3)Benefits from the security characteristics of the blockchain,our scheme can resist a variety of attacks,such as substitution attack,migration attack,collusion attack and replay attack,etc.And meanwhile,a performance evaluation is conducted to show the feasibility and efficiency of our scheme.4)Based on the above theoretical foundation,the design and implementation of the BCES platform system is completed,which preliminarily proves that the program has a certain realistic application prospect.