一种区块链交易信息的隐私保护方案

针对区块链用户交易的隐私性问题，提出了一种基于多项式承诺的交易隐私保护方案(transaction privacy protection scheme based on polynomial commitments, TPP-PC)。利用多项式在随机点处的承诺值对交易金额进行隐藏和绑定，实现对用户交易金额的隐私性保护，并且降低承诺开销；采用智能合约和零知识证明，在无可信第三方的情况下，在智能合约处利用零知识证明验证交易的合法性，有效防止交易金额在传输过程中被篡改，达到交易金额始终正确的效果；通过Paillier同态加密算法，实现在密文状态下完成账户更新，保证交易金额在存储过程中的安全。通过对方案正确性、安全性和性能的分析，表明方案既能对交易数据进行加密，又能实现用户链下交易信息的隐私，有效防止恶意者篡改数据，保证交易双方交易信息的安全性，综合优势较明显。

A privacy protection scheme for blockchain transaction information

In view of the privacy problem of blockchain user transactions, this paper proposes a transaction privacy protection scheme based on polynomial commitments (TPP-PC). This scheme uses the commitment value of polynomial at random point to hide and bind the transaction amount, so as to protect the privacy of user transaction amount. In the absence of a trusted third party, zero-knowledge proofs are used to verify the legitimacy of transaction at smart contract, to effectively prevent the transaction amount from being tampered during transmission, and to achieve the effect that the transaction amount is always correct. Through the Paillier homomorphic encryption algorithm, the account is updated in the ciphertext state to ensure the security of transaction amount in the storage process. Through the correctness, security and experimental analysis of the scheme, it shows that the scheme can not only encrypt transaction data, but also realize the privacy of user transaction information under the chain, effectively preventing malicious persons from tampering with data, and ensuring the security of transaction information between both parties. It has obvious comprehensive advantages.