Research On Bitcoin Mixing Mechanism For Transaction Privacy Protection And Supervision

Bitcoin is the first widely used encrypted digital currency and is the first blockchain application.In recent years,due to its anonymity,rapid cross-border transactions,high reliability of transactions,non-destructive and non-centralized features,it has become a payment method used by users and merchants,and some countries have even determined the legal status of Bitcoin.However,its transaction data is completely disclosed in the blockchain,and any user can obtain all transaction data,which brings about leakage of legitimate transaction privacy(total user's funds,capital flow,transaction behavior).At the same time,the illegal trade of criminals using Bitcoin for criminal activities needs effective supervision.Therefore,bitcoin transaction privacy has become the focus of research at home and abroad.This paper summarizes the deficiencies of existing Bitcoin transaction privacy protection methods,such as poor compatibility,weak protection,and lack of illicit trade regulation.Aiming at the above problems,a new mining method was designed,which proved the limitation of the existing methods.Then put forward a privacy protection program,to achieve the purpose of privacy protection and supervision.The innovations in this article mainly include two aspects:(1)A new address clustering analysis method is proposed for private address mining.It not only can realize address clustering for non-mixed currency transactions,but also supports address clustering for sending and sending mixed currency transactions.This method exploits the deficiencies in the Shared Sending Mixture Coupon protocol to identify shared send transactions from a large number of transaction records and decompose them inversely into non-mixed currency transactions.The experimental results based on real Bitcoin transaction data show that the current Bitcoin transaction accounts for about 2.6% of the shared sending transactions;the address clustering analysis method proposed in this paper improves the accuracy by approximately 40.94% compared to the existing methods.(2)For bitcoin transaction privacy protection,a centralized blending scheme based on bilinear partially blind signature and stealth address is proposed.It not only protects the privacy of users' transactions,but also supports trust institutions to implement transaction supervision.In order to solve the privacy problem of user transactions,the scheme hides the relationship between the public address of the user transaction and the actual use address by adding a coin currency service node to the existing bitcoin system,thereby realizing the unlinkability of input and output of the transaction.The program uses a set of fixed amounts to protect the transaction amount.The use of improved privacy address technology to achieve the protection of the recipient's address.In order to strengthen the supervision of Bitcoin,a third-party organization was introduced to implement user and coinage service node authentication.Theoretical analysis proves the privacy protection effect of the scheme.The experimental results show that the scheme improves the speed of authentication and blind signature by nearly 10 times compared with the existing RSA-based scheme.