Research On Transaction Content Privacy Protection Technology In Hyperledger Fabric

With the decentralized characteristics,blockchain technology has penetrated into many fields such as finance,medical treatment,and education.However,in order to achieve consistency consensus and verifiability of transaction,traditional blockchain system stipulates that all transaction parties and transaction data must be published to the entire network and stored in the blockchain ledger in the form of plain text.If malicious nodes use big data analysis and other technologies to analyze and broadcast these public transaction contents,they may obtain some additional private information.The privacy of user is difficult to ensure.In addition,many current blockchain systems cannot meet the legal supervision of transactions while achieving privacy.On the protection of transaction data privacy,this paper based on the actual application scenario of the Hyperledger fabric platform,designs auditable transaction data privacy protection schemes.First,based on the Hyperledger Fabric platform,this paper designs and implements a hierarchical auditable data privacy protection scheme based on content extraction signature.This scheme changes the signature method of the endorser in the fabric consensus process,and introduces the content extraction signature.In the case of hiding part of private data,this scheme still meets the verifiability of the endorsement signature and the privacy protection requirements.This scheme realizes the function of hierarchical supervision,provides a more flexible and secure privacy data protection mechanism,it has certain applicability in the data storage and information voucher application scenarios of the consortium blockchain.Second,in order to solve the lack of reliability supervision in the asset transaction scenario of the consortium chain,this paper proposes a privacy protection scheme for auditable transaction data based on zero-knowledge proof.This scheme allows the auditor to legally audit while hiding the transaction amount.At the same time,in order to prevent malicious users from defrauding the auditor and encrypting with invalid amounts,verifiable encryption technology is adopted to ensure the consistency between the ciphertext and the commitment.This scheme realizes the public verifiability of the ciphertext,and the auditor does not need to be online at all times.This scheme can be widely applied to digital asset transaction scenarios of the consortium blockchain.Third,in order to solve the transaction overhead caused by zero-knowledge proofs.The aggregation technology is used to aggregate multiple signatures in the transaction,which reduces the cost of each transaction and the computation of verification process.At the same time,signatures of multiple transactions in the block are aggregated into a fixed number,which reduces the transaction overhead in the block and effectively saves the ledger space.Finally,this paper implements the above schemes using Go language.The test results show that the hierarchical auditable data privacy protection scheme based on content extraction signature can selectively hide part of private data,and meet the verifiability of the signature.The private data ciphertext is uploaded to the blockchain,meets regulatory requirements.The auditable data privacy protection scheme based on zero-knowledge proof realizes the hiding of transaction amount and public verification of ciphertext,uses aggregation technology to reduce transaction overhead and improves transaction verification efficiency.