Security Model Of Medical Health Data Based On Blockchain With Privacy-Preserving

Medical health data accurately record the drugs and allergies used by each person,medical treatment information,diseases,surgeries,and vital signs.More secure storage and sharing has become a research focus in the field of electronic medical system.In practical applications,medical institutions use the cloud servers to store and share medical data.Medical institutions can upload patients' electronic medical records from the cloud,which greatly improves the efficiency of storing,retrieving and sharing medical data,but at the same time,the specific medical institution with a patients' electronic medical record can control some sensitive data not to be shared.On the other hand,the patient's electronic medical records are stored by medical institutions on semi-trusted third-party servers.If an attacker attacks a third-party server or the medical institution tempted by high-value sensitive information,all medical data on the server will be fully disclosed.Therefore,considering various types of security and privacy leakage,it is found that establish a security model can largely solve the problem of secure storage and sharing which is decentralized,traceable and tamper-proof.In this thesis,the security storage and sharing methods of medical health data from three aspects: the security model of medical health data,the consensus mechanism of medical institution alliance and the privacy-preserving of medical health data.The specific work is as follows:1.The problem of the security model of medical health data is studied.Considering the sharing difficulties among different medical institutions,the medical health data security model based on blockchain is proposed.By classifying medical institutions,alliance groups with different functions are formed.In the model,the ciphertext of original medical health data is stored in distributed database and other important information of data is stored in blockchain.Improved new models and methods of separate storage can help share health data securely.2.The problem of the consensus mechanism of medical institution alliance is studied.A security sharing method based on improved consensus mechanism is proposed to deal with the problem that low security and poor consistency in the process of medical health data sharing.In this method,the advantages and disadvantages of the five common consensus mechanisms and the roles of the two alliance groups are considered comprehensively.The model chooses to use thehybrid consensus mechanism which combines DPOS mechanism with the PBFT mechanism to improve the security and consistency in the process of medical health data sharing.Though the security analysis,consistency analysis and comparative analysis of the hybrid consensus mechanism,the results show that the model can perfectly solve the cross-agency security storage sharing of medical data among independence among the independent medical institutions by using the hybrid consensus mechanism.3.The problem of the privacy of medical health data is studied.In order to solve the problem that the single encryption mechanism for encrypting medical health data has the risk of privacy leakage,the security model of medical health data based on blockchain and privacy-preserving is proposed.By combining blockchain with cloud storage,the model adopts the hierarchical management mode and combines attribute encryption with proxy re-encryption to protect the privacy of medical health data.Compared with other schemes,the scheme in this model is more secure and practical by the security proof,privacy-preserving analysis.