安全求交集在隐私计算中的发展和应用.pptx

安全求交集在隐私计算中 的发展和应用 ; Roadmap 安全求交集(PSI)定义 PSI功能和分类 PSI必威体育精装版进展 PSI和其他隐私计算技术结合 References; Roadmap 安全求交集(PSI)定义 定义 我们还需要什么？ PSI功能和分类 PSI必威体育精装版进展 PSI和其他隐私计算技术结合 References; Private Set Intersection Alice has set X and Bob has set Y. After PSI computation, Alice learns X ∩ Y and nothing else Alice cannot know Bob’s elements that don’t belong to X ∩ Y Provable security; Normally different methods should point… Let’s do something else Assume there is a PSI protocol What else do we need from PSI?; Roadmap 安全求交集(PSI)定义 PSI功能和分类 PSI必威体育精装版进展 PSI和其他隐私计算技术结合 References; Only for two parties Alice and Bob Only semi-honest secure Attacker strictly follow protocol, but is curious for the other party’s secret information; Challenge 1: 隐藏非交集元素(hiding) Cryptographically secure“hiding” When two elements are not equal, some kind of“noise”must be attached such that unmatched elements cannot be exhaustively computed Challenge 2: 计算交集元素(comparing) When two elements are equal, their equality should be able to disclosed in some way Challenge 3: 效率高(efficiency) PSI protocol is practical for large-scale application; Hellman Key Exchange Diffie-Hellman Key Exchange PSI [3] Basic Idea:“double encryption”with commutative property Hiding:“Encryption”hides element Comparing: commutative property Efficiency Linear to communication cost Still a mainstream implementation of PSI Many enhancements on crypto primitives Design a crypto method that can meet all the requirements; (cont’d) Discrete Logarithm Problem (DLP): given g, x and y as three large positive integers, assume gx = y mod p, given y, g, p, how to find x is a “hard problem” It is efficient to compute gx mod p Efficiency It is hard to find x given y, g, p Hiding gxy mod p is equal to gyx mod p(communicative property) Comparing g, x , p and y need to satisfy a bunch of conditions of cryptography to make