Research On Blockchain Data Privacy Protection Algorithm Based On Differential Privacy

With the development of the information age,digital services bring convenience to people’s life but also cause problems such as data tampering and privacy leakage.Blockchain is widely used in various fields as a digital service technology with characteristics of"decentralization,non-tampering and traceability".However,while it provides data transparency and decentralization,it also has the problem of data privacy protection.Differential privacy,as a privacy protection strategy,has been applied in many fields in recent years,and it can protect the privacy information of individuals without destroying data characteristics.In this paper,a data publishing framework is constructed around blockchain and differential privacy,and the details of the research are as follows:(1)A blockchain data privacy protection scheme based on differential privacy is proposed for the privacy protection of shared data in blockchain networks.By integrating the differential privacy mechanism into the blockchain smart contract layer,we realize that the chain code is automatically invoked to add noise to the data during the user’s data upload,and the invocation of noisy data is completed by using the private ledger of the federated chain Hyperledger Fabric in a permission-controlled way,and the original data is stored separately from the noisy data.The noise data saved in the private ledger can be used to complete the data denoising function to respond to the data verification requests of users,and finally reach the consensus state of the blockchain network,and finally the privacy protection performance of the system is measured by the throughput and privacy consumption of the blockchain network.(2)A reuse noise response answering(RRAP)blockchain network model framework for permission chains is proposed to address the problem that the interactive differential privacy data publishing framework may degrade the privacy protection level after responding to a large number of queries.The interactive differential privacy publishing framework consumes the privacy budget with each answer to a query request from a user,which leads to a reduction in the privacy protection level when the consumption level reaches a critical value.Combined with the traceability feature of blockchain,the historically answered query questions and noisy answers are recorded in the private ledger of the federated chain,and the current queries are matched with the historical records by means of permission management,and the previous answer data can be fully or partially reused depending on the noise variance value,which can effectively guarantee the privacy level.Finally,it is further demonstrated through experiments that the adopted network model can effectively protect the privacy performance.