Abstract: Blockchain is widely used because of its distributed processing, multiparty consensus, and immutable data. However, the open and transparent processing method will leak the privacy of users, and it is particularly important to use encryption technology to prevent the leakage of sensitive information. This paper proposes a privacy protection scheme for blockchain transactions based on threshold homomorphic encryption algorithm. Firstly, the confidentiality of sensitive transaction data is guaranteed by homomorphic encryption of the user’s account balance and transfer amount; Then, the corresponding transaction confirmation and transaction verification methods are designed. Finally, the security analysis and experimental verification of the proposed scheme are carried out, and the results show that the scheme has good stability and scalability, and is suitable for the general account model blockchain system.

Key words: threshold homomorphic encryption, blockchain, transaction, privacy protection, account model

摘要： 区块链因其分布式处理、多方共识、数据不可篡改的特性而被广泛应用.然而公开透明的处理模式会泄露用户的隐私，如何使用加密技术防止敏感信息泄露显得尤为重要.提出基于门限同态加密算法的区块链交易隐私保护方案.首先，通过对用户的账户余额和转账金额进行同态加密，保证敏感交易数据的机密性；然后，设计相应的交易确认和交易验证方法；最后，对该方案进行了安全性分析和实验验证，结果表明，该方案具有良好的稳定性和扩展性，适用于通用的账户模型区块链系统.

关键词: 门限同态加密, 区块链, 交易, 隐私保护, 账户模型