Research On Data Privacy Blockchain Based On Full Homomorphic Encryption

The transaction data on the Public Blockchain can be seen on the whole network.By collecting the transaction records on the Public Blockchain and analyzing a large number of transaction information,there is a great probability that the actual transfer route of the transaction amount can be traced,and even the real users can be traced.In order to obtain some information that may damage the privacy of users,which is not conducive to the legitimate privacy protection of individuals or organizations.Therefore,the encryption of data information on the Blockchain is very important for the privacy protection of users on the Blockchain.Taking user transaction as an example,in view of the fact that the transaction model of traditional Blockchain cannot protect the users'data privacy,this paper introduces the Zero-Knowledge Proof technology into the transaction protocol of Blockchain based on the Fully Homomorphic Encryption without Bootstrapping,and designs the Blockchain to protect data privacy.The research content of this paper mainly includes the following two aspects:?1?The paper researches the Blockchain Transaction Protocol based on Fully Homomorphic Encryption,including Equal Transaction Protocol and Full Transaction Protocol.The way of Fully Homomorphic Encryption hides transaction amount and account balance on basis of the traditional transaction model of Blockchain.Equal Transaction Protocol of Blockchain based on the Fully Homomorphic Encryption,Zero-Knowledge Proof is used to prove that the ciphertext of two transaction amounts encrypted by the Fully Homomorphic Encryption Algorithm under different keys contains same plaintext.Full Transaction Protocol of Blockchain based on Fully Homomorphic Encryption,it constructs a Non-interactive Minimum Necessary Zero-Knowledge Proof by using the Interval Membership,which enables the miner to verify that the account balance of transaction initiator is greater than or equal to the transaction amount before the transaction without decryption.?2?The paper researches data privacy Blockchain based on Fully Homomorphic Encryption.Based on the Blockchain Transaction Protocol of Fully Homomorphic Encryption,the Blockchain of data privacy protection based on Smart Contract is constructed.The constructed Blockchain to protect data privacy is a verification process deployed on Blockchain,the Smart Contract on Blockchain will be triggered to execute correctly after transaction information is verified,and the Smart Contract will update the ciphertext of account balance from both parties according to the execution result.The use of Fully Homomorphic Encryption Algorithm can make any third party of transaction on the Blockchain to complete the verification of change operation,it also can make the Smart Contract on the Blockchain to process ciphertext,and not know the plaintext,which significantly improves the security of user data privacy.The Blockchain of privacy can hide the input,output and transaction details of the traditional Blockchain transaction system.When Hash length is k,the probability that the privacy Blockchain can be broken is 2^-k.That is to say,the security strength of Blockchain is 2^k.In this paper,Equal amount and Full amount Blockchain Transaction Protocols based on Fully Homomorphic Encryption are proposed,and data privacy protection Blockchain based on Fully Homomorphic Encryption is constructed,which can effectively protect the data privacy of users on the Blockchain and extend the application scenario of the Blockchain.