Research On Blockchain Privacy Protection Based On Homomorphic Encryption And Zero Knowledge Proof

The privacy protection of blockchain is a hot topic in the field of blockchain technology research.The blockchain platform based on the Fabric project in the alliance chain is being applied in more and more enterprises.However,the ledgers in Fabric are transparent to the organizations involved in maintaining the blockchain.When the user uses the blockchain to complete the transaction process,the user's financial situation and the transaction amount and other private information are easily leaked,which is unacceptable in many fields,especially for industries such as the financial industry that pay great attention to user privacy.Therefore,privacy issues have gradually become one of the main obstacles to the promotion of blockchain applications.By analyzing the encryption characteristics of the existing Paillier algorithm and combining the problems in the transaction process in the blockchain,this paper studies the possibility of using the algorithm to solve the privacy problem of blockchain.The research results show that the algorithm used in the blockchain can encrypt the data in the user transaction process,but it can not prove the zero-knowledge of the transaction result,which is easy to generate the risk of the user maliciously trading.Therefore,this paper adds ciphertext domain that can be used for zero-knowledge proof for Paillier algorithm,and modifies the encryption and decryptio n process of Paillier algorithm.Then,according to the requirements of completing the zero-knowledge proof in the blockchain,we proposesd a homomorphic encryption algorithm??HEPZP(Homomorphic Encryption Based on Paillier and Zero-Knowledge Proof)algorithm.The algorithm can not only encrypt the transaction data in the blockchain,but also enable the smart contract to verify the legality of the transaction when the transaction data is ciphertext.In order to verify the rationality and operational efficiency of the algorithm,this paper took UTXO model in the transaction process as an example to test it,and analyzed the application effect of the algorithm in the blockchain privacy protection process in detail.The analysis results show that the algorithm can effectively protect the privacy of the user in the process of using the blockchain,and has better operating efficiency.At the same time,the algorithm can also ensure the security of the algorithm by increasing the length of the key.Therefore,the algorithm can be applied to scenarios that require privacy protection for blockchains.