| Blockchain is a chain database based on time order on the distributed peer-to-peer network.It uses cryptography to realize the security of each link,and is a new technology to solve the privacy risk and security vulnerability in the distributed peer-to-peer network.The technology can reduce the cost of financial transactions and is expected to change the existing financial trading mode.At the same time,blockchain technology has a broad application prospect in the fields of Internet of things,smart grid,supply chain,copyright protection,government affairs publicity and so on.Blockchain is built on peer-to-peer network without trusted center.Users in blockchain access account assets with account private key,which provides privacy protection for users,and also makes users in blockchain face two types of account wallet security problems: wallet theft and wallet loss.If the wallet is stolen,the thief can transfer the account assets with the private key in the wallet.Due to the irrevocability of the blockchain,the account assets cannot be retrieved.If the user loses the wallet associated with the account,because there is no trusted center on the blockchain to keep the user wallet,the private key stored in the wallet cannot be recovered after the wallet is lost,and the user will not be able to access the account and lose control over the account.Therefore,in view of the security of blockchain wallet,two blockchain wallet protection schemes are proposed in this paper(1)In view of the problem that blockchain wallet cannot be recovered after losing,a scheme of blockchain wallet backup based on threshold secret sharing mechanism is proposed.The scheme can realize the recovery function of wallet after losing without trusted third party participation,and ensure the security of block chain user account assets.According to the threshold secret sharing idea,the scheme divides the secret of blockchain wallet into fragments combined with the password set by the user,and then it is kept by other members of the network,so as to realize the distributed backup and storage of blockchain wallet.The threshold threshold is 1/3 of the total number of users in the blockchain according to the practical Byzantine fault tolerance mechanism.As long as the system can reach an agreement based on the practical Byzantine fault tolerance algorithm and operate normally,the user can complete the distribution and collection of wallet fragments,and realize the backup of wallet and the reconstruction of the private key of the wallet.(2)In order to solve the problem of blockchain wallet theft and loss,a new scheme of blockchain wallet signature based on the elliptic curve digital signature without credible center threshold is proposed.The scheme can protect blockchain wallets from the threat of wallet theft and wallet loss.In the scheme,the participants cooperate to generate public-private key and their private key fragments without the participation of trusted center.Only the participants who exceed the threshold threshold can sign the transaction effectively.Only the account private key fragment is saved by a single participant.Malicious attackers need to collect the private key fragments exceeding the threshold threshold.If the participant improperly keeps wallet fragments and causes them to lose,it will not lead to inaccessible blockchain accounts,and the lost wallet fragments can be recovered by using threshold key.The results show that the scheme can meet the security requirements,effectively guarantee the security of blockchain wallet and enhance the availability of blockchain products. |
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