Research On Secure Access Mechanism Of Medical Data For Heterogeneous Platform

The continuous development of information technology has brought about the popularity of digital medical care such as mobile health care and electronic medical records.Collaborative treatment of diseases and multi-platform medical research and analysis are of great significance to patient treatment and medical research.In the collaborative use of medical data,the clinical data and group medical information contained therein will cause irreparable losses if they are illegally used.How to safely store medical data and multi-party computing and secure access to data based on heterogeneous platform are the key and difficult problems to fully utilize medical data resources.Blockchain technology has the characteristics of decentralization,immutability and openness and transparency.It is a new kind of solution to the multi-party trust problem at present,and can provide more secure underlying support for the access and flow process of medical data on heterogeneous platforms.Therefore,based on blockchain technology,this thesis studies the secure access control mechanism of medical data on heterogeneous platforms.The main work contents are as follows:(1)In view of the information security issues in the distribution and use of medical data on heterogeneous platforms,a blockchain-based medical data secure storage model is proposed,which contains a secure multi-party computing method with transparent process.In this model,the authentication and initialization of relevant parties of the data are completed by using the block chain of the federation.Symmetry encryption is used for common storage requirements,and homomorphic encryption is carried out for the data requiring multi-party computation.The ciphertext of the data is stored in IPFS to obtain CID.Then the data owner identity,CID and homomorphic cryptographic public key are stored on the chain.The computing service provider invokes the smart contract to perform homomorphic operations and records the calculation results on the chain.In the above process,medical data is always circulated and stored in the form of high-intensity ciphertext,which ensures the privacy of medical data.The validity and efficiency of the model are verified by experiments and analysis.(2)Aiming at the problem of insufficient security and flexibility of data access control in medical environment,a fine-grained secure access control model based on block chain was proposed by combining block chain with ABAC model.Firstly,the model obtains the CP-ABE private key according to the attribute set and initiates an access application to the blockchain.Then,after the smart contract verification,the AES key encrypted by Cp-ABE is returned.When the attribute set of the data requester meets the access control requirements,the AES key can be decrypted and obtained,and then the data ciphertext packet downloaded from the distributed storage system can be decrypted and the data access rights can be obtained.The access request must be verified by the time limit information and attribute revocation in the smart contract,which solves the reliability and flexibility problems in the access control of medical data on heterogeneous platforms to a certain extent.The validity and safety of the model are verified by experiments and analysis.