按需披露的区块链隐私保护机制

隐私保护已经成为区块链技术真正从理论到现实应用必须解决的关键问题。实际应用中存在一种按需披露的隐私保护需求，受组播安全通信机制的启发，提出一种按需披露的区块链隐私保护机制（PPM-ODB，privacy protection mechanism of on-demand disclosure on blockchain）。该机制通过改进基于RSA的匿名多接收者加密方案来实现隐私信息一对多的加解密、知情者的匿名性保护和隐私泄露的可追溯，通过采用 Quorum 链隐私保护机制来实现密钥在隐私信息拥有者和知情者间的安全高效分发。实验证明了PPM-ODB 机制可保证隐私数据的保密性，及其在时间和存储开销上的优越性，并建议知情者的个数少于100，以获得良好的用户体验。

Privacy protection mechanism of on-demand disclosure on blockchain

Privacy protection has become the key problem that blockchain technology must solve from theory to practice.There is a privacy protection requirement of on-demand disclosure in practical applications.Inspired by multicast secure communication mechanism,a privacy protection mechanism of on-demand disclosure on blockchain was proposed.This mechanism improves the RSA based anonymous multi receiver encryption scheme to realize the disclosure of the private data on the blockchain only to the permitted informed,the anonymity protection of the informed and the traceability of the privacy disclosure.The Quorum blockchain privacy protection mechanism is adopted to realize the safe and efficient distribution of the key between the owner of the private information and the informed.Finally,it is proved that PPM-ODB mechanism can guarantee the privacy of privacy data and its superiority in time and storage cost,and it is suggested that the number of informed people should be less than 100 to obtain a good user experience.