Controllable Sharing And Management Scheme Of Medical Data Based On Double-chain

In recent years,the medical field has gradually entered the digital era,and electronic medical records have begun to replace the traditional paper medical records.The centralized storage architecture commonly adopted by medical institutions is no longer suitable for the explosive growth of data,which has caused the phenomenon of data silos on the one hand;on the other hand,there are conditions such as leakage of patient privacy data,so how to share medical data under the premise of security and control and break the data silos has become an urgent problem for electronic medical record system.The decentralization,tamper-evident and traceability of blockchain technology provides a new direction to solve the above problems.Therefore,this paper is based on blockchain technology for the safe storage and controlled sharing of medical data,and the specific work is as follows:(1)A controlled and secure sharing model of medical data based on dualblockchain is proposed to address the problems of traditional medical data sharing systems such as difficult cross-institutional sharing and difficult supervision.It adopts a double-chain structure to ensure secure data sharing across institutions and uses onchain and off-chain cooperative storage to solve the problems of excessive pressure on a single chain and limited storage space on the chain.Subsequently,the concepts of patient directory and derivative chain are proposed to enable the tracking of on-chain data as well as to realize fast indexing of data.Finally,fine-grained access control of data is achieved using attribute-based encryption and symmetric encryption.The comparison analysis shows that the scheme in this paper not only relieves the pressure of single chain,improves the interoperability and sharing of data,but also provides fast indexing function.Simulation experiments show that the scheme in this paper performs well in terms of time efficiency and query latency.(2)According to the master node selection problem and efficiency problem of the PBFT consensus algorithm adopted in the above scheme.A multi-storey practical Byzantine fault-tolerant consensus algorithm(Multi-Storey PBFT,MS-PBFT)is proposed by combining the characteristics of the federated chain and the model framework in the above scheme.The initial points and reputation values are introduced to score the nodes according to their performance as well as their performance in the consensus process,and the nodes are divided according to the points to ensure the performance as well as the reliability of the nodes participating in the consensus.And by stratifying the consensus nodes,the communication time between nodes is reduced and the consensus efficiency is improved by reaching local consensus and then global consensus;node election and impeachment mechanisms are set to improve the reliability of nodes.The simulation experiments show that the scheme in this paper outperforms the traditional PBFT algorithm in improving data throughput,reducing consensus delay and ensuring node reliability.