区块链密码学隐私保护技术综述
Survey on blockchain privacy protection techniques in cryptography
Abstract
近年来，数据隐私问题日益明显，如何在区块链中实现有效的隐私保护是研究热点。针对区块链在隐私保护上的研究现状与发展态势，阐述了区块链在交易地址、预言机以及智能合约上的隐私保护方法，归纳出区块链在基本要素防护上的隐私策略。基于国内外高水平文献梳理分析了特殊密码学原语、后量子密码学两类区块链密码学防护方法及使用场景，综述其研究思路，并给出属性基加密、特殊数据签名、同态加密、安全多方计算、零知识证明、格密码等适用于区块链隐私保护的密码学技术的优缺点，得出区块链应用的隐私防护离不开密码学技术支持的结论。针对区块链隐私保护技术，从基本要素防护和密码学防护两个方面进行了分析，总结出仅从区块链的应用层、合约层出发难以有效解决隐私问题，还需要利用各类密码学技术根据需求和应用场景的不同进行优势互补。根据区块链隐私加密技术发展现状，从区块链基本要素防护和基于密码学的防护展开叙述。从内生性基本要素安全和外生性密码学隐私安全两个角度出发，先研究基本要素隐私防护，再深入分析区块链隐私密码学防护技术。在对应防护措施中以技术联合实际应用发展，考虑技术时效性的同时，衡量其隐私处理方面的优劣势以及潜在价值。展望了未来区块链隐私保护技术的发展方向，说明了需要重点解决的问题。
In recent years, the issue of data privacy has attracted increased attention, and how to achieve effective privacy protection in blockchain is a new research hotspot.In view of the current research status and development trend of blockchain in privacy protection, the privacy protection methods of blockchain in transaction address,prophecy machine and smart contract were explained, and the privacy strategies of blockchain in the protection of basic elements were summarized.Based on high-level literature at home and abroad, two types of blockchain cryptographic protection methods and usage scenarios were analyzed, including special cryptographic primitives and post-quantum cryptography.The advantages and disadvantages of seven cryptographic techniques applicable to current blockchain privacy protection were also reviewed, including attribute-based encryption, special data signature, homomorphic encryption, secure multi-party computation, zero-knowledge proofs, and lattice ciphers.It was concluded that the privacy protection of blockchain applications cannot be achieved without cryptographic technology.Meanwhile, the blockchain privacy protection technologies were analyzed in terms of both basic element protection and cryptographic protection.It was concluded that it was difficult to effectively solve the privacy problem only from the application and contract layers of the blockchain, and various cryptographic technologies should be used to complement each other according to different needs and application scenarios.In addition, according to the current development status of blockchain privacy cryptography, the narrative was developed from blockchain basic element protection and cryptography-based protection.From the perspectives of both endogenous basic element security and exogenous cryptographic privacy security, basic element privacy protection should be studied first, followed by an in-depth analysis of cryptographic protection techniques for blockchain privacy.The strengths and weaknesses and the potential value of the privacy handling aspects of the corresponding safeguards should be measured in terms of the development of technology in conjunction with practical applications, while considering the timeliness of the technology.Finally, an outlook on the future direction of blockchain privacy protection technologies was provided, indicating the issues that need to be addressed in focus.