Research On Data Validation Mechanism In Privacy-Preserving Scenarios On A Consortium Blockchain

With the high efficiency,low overhead,and high scalability,the consortium blockchain has been gradually and deeply applied to all walks of life.Since the data on the chain is open to the members of the consortium blockchain network,the transaction information written directly into the ledger will reveal the commercial privacy of both parties.Therefore,the business application data should be encrypted when published as a transaction on the consortium blockchain.However,third parties still need to verify sensitive private data relationships on the consortium blockchain for private transaction information.The current research is mainly based on public blockchains regarding the verifiability of privacy transaction information in the blockchain.Nevertheless,the differences in consensus mechanism and operation process with the consortium blockchains make the existing solutions cannot be directly applied to the consortium blockchain.No research has yet focused on the verifiability of private data in encrypted transactions for consortium blockchain business applications.Therefore,how to effectively meet the verifiability of encrypted business application data on the consortium blockchain is an urgent issue to be addressed.As the transactions in business applications also involve the flow of money among various roles,various privacy trading applications also have the demand to directly utilize the privacy tokens in the chain to hide the transaction amount and account balance.It can better protect the privacy of money among traders and further leverage the advantages of the consortium blockchain.Most of the existing privacy-protection currencies belong to the UTXO model,which is less scalable and has a higher overhead in storage and computation.At the same time,the current privacy token model based on the account model also suffers from various shortcomings such as the offline transmission of information,low encrypted efficiency,and insufficient scalability.Therefore,there is no more apparent solution on the consortium blockchain for privacy-preserving transaction information,both to do direct transactions using in-chain privacy tokens for transactions in a privacy context and to verify the legitimacy of account balance changes before ensuring they can be paid.In response to the problems above,this thesis investigates the verification mechanism of transaction privacy data based on zero-knowledge proof technology in the privacy-preserving scenario of a consortium blockchain.This thesis designs and implements an encrypted transaction privacy data verification model and account model privacy token transaction model adapted to the consortium blockchain,which mainly includes the following points:1.Vmpp Frame,a privacy data verification model for encrypted transactions based on zero-knowledge proof,is proposed to effectively satisfy the verifiability of encrypted business application data on the consortium blockchain.The model takes the typical order financing application scenario as an example on the consortium blockchain,designs the relationship between privacy data based on the business scenario,and constructs the corresponding zeroknowledge proof arithmetic circuit.Furthermore,it is encapsulated into a zero-knowledge proof library for application in the consortium blockchain network.Using the zero-knowledge proof to generate various sensitive data relationship credentials in the transaction,the third-party investor only needs to verify the data relationship with the zero-knowledge proof credential.It achieves the goal of verifying the transaction data relationship in an encrypted state while protecting the privacy of both parties to the transaction.This thesis also analyzes the security of the zero-knowledge proof arithmetic circuit constructed by the order data.Finally,the experimental results show that the Vmpp Frame has high performance in both calculation and processing.2.Vmpp Token,an account model privacy token transaction model based on zeroknowledge proof,is proposed.It addresses the problem of how to directly use privacy tokens on the consortium blockchain for trading in a privacy context and verifying the legitimacy of account balance changes before ensuring that the transactions can be paid.The model is based on the relationship between the account balance and the transaction amount.By participants using the zero-knowledge proof to generate the data relationship credentials for each privacy token transaction,it enables each endorsing peer node only needs to verify the data relationship for the zero-knowledge proof credentials before writing into the ledger.It achieves the goal of guaranteeing the legitimacy and effectiveness of various transactions while protecting the transaction privacy of each participant.This thesis also analyzes the security of the zeroknowledge proof arithmetic circuit constructed by token recharge,token transfer out,and in.Finally,the experimental results show that Vmpp Token has a higher performance in calculation and processing than the Block Maze scheme.3.A prototype system for privacy data verifiability of encrypted transactions supporting privacy tokens on the consortium blockchain is designed and implemented.The design details of the system are described in three aspects: the zero-knowledge proof processing module,the consortium blockchain transaction processing module,and the interactive interface processing module,respectively.In addition,the system can run and demonstrate with an interactive interface.The running results show that the system realizes that the verifier can verify the encrypted sensitive transaction information without decryption and support privacy transactions using the tokens in the chain by constructing zero-knowledge proof credentials for transaction privacy information.