Research On Blockchain-Based Over-Loan Prevent Mechanism And Privacv Protection Technology

When lending at a bank,the creditworthiness and repayment ability of borrowers have become the criteria for whether borrowers can successfully borrow from banks.At present,whether Banks or other lending institutions,credit investigation on borrowers mainly comes from credit investigation agencies,which are responsible for collecting personal information and other credit data of borrowers,and generating credit investigation reports of borrowers.However,in these processes,the data is transmitted in a plaintext,this transmission method would leak the privacy of banks and borrowers.And storing data centrally in a local database is vulnerable to hackers and faces the risk of data being modified and deleted.Therefore,it is necessary to protect the privacy data of customers and banks when sharing data,and at the same time solve the problems of data correctness and accuracy."Blockchain" was proposed by Nakamoto in "Bitcoin-A Peer-to-Peer Electronic Cash System" published in 2008.Blockchain was originally proposed as the core underlying technology of Bitcoin,and it gradually expanded to e-government,e-contracts,Internet of Things,traceability,copyright certification,etc.Blockchain technology is non-tamperable and open and transparent.Therefore,based on the blockchain technology and cryptographic technologies,a blockchain-based over-loan prevent mechanism is proposed to solve the problems of data sharing and privacy leakage in the bank credit industry.This article has the following three innovations:(1)Aiming at the problem of data privacy leakage,this article proposes a blockchain-based over-loan prevention(BBOLP)mechanism.In this mechanism,the borrower hides the loan/repayment amount in the proof,and others can judge the validity of the data through the proof,that is,the borrower does not over loans,but cannot obtain other information,so that it makes the data publicly verifiable under privacy protection.At the same time,the data is stored on the blockchain can achieve public access to the data,reduce the communication between the bank and the credit bureau,solve the problem of a single point of failure in the local central database,and improve the credibility of the data.(2)Aiming at the problem that the communication volume will increase linearly when the length of binary string is long in the BBOLP mechanism,this article uses the Bulletproofs algorithm to improve the BBOLP mechanism,reduce the communication volume of participants,and propose a low-communication-volume BBOLP mechanism.In the BBOLP,the loan/repayment amount needs to be divided into bits before generating the range proof,the commitment of each bit of the binary string is used to generate the two-ring signature public key groups,then a ring signature is generated.When the length of the binary string is large enough,the ring signature generated will also be large,and therefore,excessive resources will be consumed during communication.The range proof is the main part of the total communication volume.The size of the range proof can be reduced to a logarithmic level by the Bulletproofs algorithm when generating a range proof,so that it can reduce the communication volume of BBOLP mechanism effectively.