Research And Implementation On Blockchain Privacy Protection Scheme Based On Homomorphic Encryption And Zero-knowledge Proof

As a decentralized distributed public ledger technology in P2 P networks,blockchain has attracted extensive attention in recent years.However,due to the openness of blockchain,there are significant privacy costs associated with completely removing trusted centers.Many existing cryptocurrencies do not provide the anonymity and confidentiality of transactions,meaning the addresses of both parties and the amount of transactions are publicly accessible.As concerns over privacy issues have grown,many academic studies have sought to enhance the privacy protection of blockchain by leveraging encryption technology.This paper studies and analyzes the existing privacy protection technology,and proposes a new solution based on the existing technology :(1)Improve the El-Gamal homomorphic encryption algorithm,and apply it to the data encryption in the blockchain.Two generators are used to encrypt the ciphertext,so that the ciphertext has the format of Pedersen commitment,which is easy to construct the zero-knowledge proof.At the same time,by using elliptic curve group instead of the module group,the problem of the original algorithm under the chosen-plaintext attack is solved.(2)Combined with the Bulletproof zero-knowledge proofs and Sigma zeroknowledge protocol,the validation of the encrypted transactions,including the correctness of ciphertext encryption and the correctness of the transaction amount and account balance range,can be realized without other useful information leakage.(3)Design the blockchain transaction scheme based on homomorphic encryption and zeroknowledge proof,realize the privacy protection of transaction data in the blockchain,build a complete encrypted account model and transaction model,design and implement data encryption and decryption module,design and implement the transaction generation and verification module.