Research On Blockchain Data Privacy Protection Method Based On Zero Knowledge Proof

The rapid development of the Internet has promoted the development of human society,but on the other hand,privacy issues have become more serious because of the rapid development of the Internet.As the next-generation value Internet,blockchain is considered to be a very good tool for protecting privacy.However,in the current blockchain network,once the digital wallet address corresponds to the personal information of its owner,all account information and transaction information owner of the wallet will be glorified in the entire network and cannot be eliminated,which will lead to a more serious problem than the disclosure of privacy on the Internet.With the development of technology,an atomic exchange transaction method has been generated in cross-chain transactions on the blockchain.Both parties to the transaction exchange assets through smart contracts,and use Hashed-Time Lock Contract to avoid malicious transactions between the two parties.Atomic exchange can enable participants to exchange assets equally and freely,but atomic exchange cannot guarantee the anonymity of transactions,which will inevitably increase the risk of privacy leakage.Zero-knowledge proof is a kind of encryption technology in cryptography,which refers to the fact that the transaction originator does not need to present any useful knowledge,so that the recipient of the transaction can believe that they really have this knowledge.Therefore,combining zero-knowledge proof with blockchain can protect the privacy of users on the chain.Encryption with zeroknowledge proofs during transactions does not expose the private information of both parties to the transaction.The main work of this thesis is to design an anonymous scheme based on the atomic exchange of the blockchain.Using zero-knowledge proofs,the transaction protocol is improved to ensure the anonymity of the atomic exchange.It can be divided into the following two parts:(1)Smart contract is the execution mechanism of cross-chain atomic exchange.In this thesis,a new anonymous list design scheme is added to the contract input side of the smart contract to ensure the anonymity of the sender;At the same time,at the output of the smart contract,a one-time address is used to protect the identity information of the transaction recipient.According to the characteristics of blockchain decentralization,taking advantage of distributed nodes,it is designed to use distributed zero-knowledge proofs for challenge verification.(2)In the atomic exchange,there is a process of direct communication between the two parties of the transaction.Therefore,this thesis improves the protocol of the atomic exchange sender and receiver to pass the key.A new smart contract is added to pass the key,which guarantees the transaction sender and The anonymity and security of the receiver's key transfer process.