Privacy protection method for blockchain transaction data based on homomorphic encryption and zero-knowledge proof

All users have access to the details of all transactions through the public ledger thanks to the distributed characteristics of the blockchain. However, attackers may infer the identities of the parties through detailed transaction data, and impair the privacy of users. Among these data, the transaction value is one of the most important transaction data. Therefore, for the privacy protection during blockchain transactions, this paper, based on the homomorphic encryption technology, enabled the committer peer to update the ledger during the transaction without knowing the balance of the parties' accounts and the transaction value. Meanwhile, the zero-knowledge proof scheme was introduced. It was proved by interval range that the committer peer can verify the validity of the transaction without knowing the transaction value.