Research On Application Of Digital Signature In Bitcoin Security Transaction

Bitcoin transactions are implemented through digital signatures,and all transactions are recorded and stored in an open database called the blockchain.With the development of Internet finance in recent years,bitcoin has increasingly influenced and changed people's lifestyles and transaction methods based on its own decentralization,global circulation,and low transaction fees features.However,the rapid development of the Bitcoin system has also exposed many problems in Bitcoin transactions.First,because Bitcoin transactions are recorded and stored in an immutable blockchain,that is to say,Bitcoin transactions are irreversible.Once a user's wallet private key is stolen and Bitcoin is transferred,then the user's property is lost and cannot be recovered.Secondly,because the blockchain that stores bitcoin transaction records is an open and transparent database,now many illegal people have stolen users' private data from big data,machine learning and other related data mining algorithms to trace users' bitcoin funds.Therefore,how to ensure the security of the secret private key in the user's bitcoin wallet and protect the user's privacy during the transaction are two issues that need to be solved in the current development of the bitcoin system.Aiming at the above two issues,this paper mainly studies the application of digital signatures in Bitcoin secure transactions and completes the following tasks: 1.Aiming at the theft of the private key in the Bitcoin wallet,a Bitcoin wallet control scheme based on a weighted threshold signature is proposed.In the system,Bitcoin wallet users use a weighted secret sharing scheme to distribute secret shares to players in the system.When Bitcoin transaction transfers are required,players use threshold signatures to confirm transaction information,thereby realizing joint control of Bitcoin wallet.First of all,this scheme uses the secret sharing scheme to decentralize the user's private key,avoiding a single point of failure,can effectively prevent the theft of bitcoin private key,at the same time,it distributes different weighted shares of private key based on players' levels,which makes the scheme practical and flexible.Second,players use a secure multi-party computing tools to jointly generate a threshold signature when construct Bitcoin transactions.During this period,the user's Bitcoin private key will not be leaked,which enhances the security of Bitcoin transactions.We give the security and efficiency analysis of the scheme.2.Aiming at the problem of privacy disclosure of bitcoin transaction records,a multi-center bitcoin mixed coin scheme based on blind ring signature was proposed.By introducing multiple coin mixing service providers to provide users with obfuscation services,adding confusion to the Bitcoin transactions between users,to realize the unlinkability of transaction's input addresses and output addresses,and further enhance the anonymity of Bitcoin transactions.Using the blind ring signature technology,the user's privacy data and the identity information of the coin mixing service provider are protected separately,and two-way privacy preserving is achieved.In addition,the scheme uses bitcoin script,which is compatible with the existing system and realizes a fair transaction between users and coin mixing service providers.Finally,the simulation and efficiency analysis of the signature algorithm are given,as well as security proof.