Research On Medical Data Access Control And Sharing Scheme Based On Blockchain

Smart healthcare plays an important role in people's lives.Access control and sharing of medical data with the great significance to the development of smart healthcare.However,the security problems in the sharing of medical data cannot be ignored.First of all,the data information in most medical institutions is managed by centralized storage,and there are many hidden security risks in centralized storage.Once the storage server is hacked,it will cause large-scale data loss and the privacy of users will be made public;then,electronic medical systems of different medical institutions are very different.It is very difficult to combine these medical systems with different architectures to achieve data sharing.Finally,most medical institutions implement access control by setting access permissions,and it takes a lot of time to perform data access.Permission verification reduces the efficiency of data sharing.The decentralization,traceability,anti-tampering,and anti-counterfeiting features of the blockchain have attracted the attention of the financial community,government departments,and academia,and become a key technology for the safe sharing of medical data.In order to solve the above problems,this paper has made detailed research on access control and sharing of medical data based on blockchain technology.The main research contents are as follows:(1)A medical data access control scheme based on attribute-based encryption is proposed.In the scheme,the decryption key of the data visitor is negotiated and generated by the data owner and the supervisory authority.The data visitor needs to submit the access attribute to the supervisory authority.The supervisory authority uses the access attribute to generate a part of the key to the visitor.Through comparative analysis,the scheme achieves access control to the internal nodes of medical institutions under the premise of ensuring data confidentiality and can also resist collusion attacks.(2)An improved practical Byzantine fault tolerance algorithm is proposed.The algorithm draws on the idea of a representative node integral up-down mechanism in the dynamic authorization Byzantine fault-tolerant algorithm,and introduces a simplified consistency protocol and a new node integral up-down mechanism.It includes three aspects,transaction delays,communication overhead,and throughput,the practical Byzantine fault-tolerant algorithm and the improved algorithm are compared and analyzed experimentally.The experimental results show that the throughput of the improved algorithm is significantly higher than the practical Byzantine fault-tolerant algorithm,and the communication volume between the nodes is much lower than the practical Byzantine fault-tolerant algorithm under the same number of system nodes.(3)A medical data access control and sharing scheme based on blockchain is proposed.In this plan,medical institutions are divided into several levels according to administrative regions.The internal nodes of medical institutions belong to the same chain.One chain is used for data sharing among medical institutions in the same region,and one chain is used for data sharing among medical institutions in different regions,that is,a three-chain structure.The internal nodes of the medical institution use symmetric encryption algorithms to ensure the confidentiality of medical data,and use the attribute-based encryption algorithm to encrypt the address index and symmetric encryption key corresponding to the cipher text of medical information and upload them to the blockchain to achieve access control and sharing of medical data.