Research On Bitcoin Key Management Scheme Based On Elliptic Curve Digital Signature

Bitcoin has many advantages such as anonymous transactions,low transaction fees,and convenient cross-border transfers.It has gradually become widely popular around the world,and has made huge room for development in investment management.However,bitcoin loss caused by hacking,system failure or human error has caused serious economic losses to individuals or businesses.Bitcoin security has become the focus of Bitcoin users.The traditional method of storing bitcoin keys in a single location makes it easy for hackers to steal all user funds anonymously and irreversibly.Joint control of bitcoin can effectively solve this problem.If an attacker wants to steal the user's bitcoin,he needs to destroy at least a threshold number of devices.Therefore,for various application scenarios,this thesis proposes three joint management schemes of Bitcoin keys with different functional advantages:First,in view of the security management of bitcoin keys for individual merchants,a strongly anonymous bitcoin key management scheme based on Two-party ECDSA is proposed.The Diffie-Hellman protocol is used to generate the Bitcoin key,the Coin Shuffle protocol is used to create the Bitcoin transaction,and the Two-party ECDSA is used to digitally sign the transaction,thereby enhancing the user's anonymity while also achieving the user's double authentication of the Bitcoin key.In addition,the scheme also designed an accountability mechanism to enhance the robustness of the scheme.Security analysis shows that this solution can resist multiple attacks such as man-in-the-middle attacks and de-anonymous attacks,and the transactions created are not different from standard Bitcoin transactions and are fully compatible with existing Bitcoin systems.Secondly,in order to solve the problem of Bitcoin key security management for small and medium-sized enterprises or groups,a key update scheme for bitcoin key management based on threshold ECDSA is proposed.This scheme utilizes the threshold ECDSA to achieve joint signature of Bitcoin transactions,thereby preventing a single malicious member from illegally using group funds.In addition,all members can regularly update their private keys,making it necessary for an attacker to steal at least a threshold number of private keys in a limited time to steal Bitcoin,which greatly increases the difficulty of the attacker.Security analysis shows that under the premise of effectively ensuring the anonymity of all members,the entire solution also has four security features: decentralization,the legality of a Bitcoin address,the unforgeability of digital signatures,and resistance to collusion attacks.Finally,for the security management of keys for individuals or groups that need to store large amounts of bitcoin funds,a key management center KMC can be introduced to assist in managing user's funds.A joint cryptographic key management scheme based on blind ECDSA is proposed.To ensure that the user's address is anonymous to KMC,a "one-way" DH protocol is used to generate a Bitcoin address;a blind ECDSA is used to generate a signature for a Bitcoin transaction.Security analysis shows that the address generated by the scheme is legitimate,and the signature is blind and unforgeable.In addition,this solution also continues to use multiple addresses to expand the number of KMCs to n,to achieve users' multiple protection of Bitcoin funds.