Research On Verifiable Privacy Set Intersection Protocol In Cloud Environment

As cloud computing continues to develop and mature,more and more users outsource local private data to cloud server for computing.At the same time,cloud data is maliciously tampered with,and security issues such as user privacy leakage have become increasingly serious.The private set intersection(PSI)protocol can protect user privacy while realizing cloud outsourced set intersection computation,which provides a reliable guarantee for promoting cloud security computing to a certain extent.However,existing private set intersection protocols are dedicated to preventing user privacy leakage,ignoring issues such as verifiability of cloud computing results and resistance to collusion attacks.On the one hand,the cloud server may tamper with and return incorrect computation results for the purpose of economic benefits or saving computing resources.On the other hand,in order to meet a wider range of practical application scenarios,the two-party computation is extended to multi-party computation,and the risk of the cloud server and users collusion leading to privacy leakage of other honest users also increases.Therefore,in order to solve the two major problems of user privacy leakage and computation result tampering,the following two verifiable private set intersection protocols are proposed in this paper:(1)Two-party private set intersection protocol based on re-encryptionIn this paper,a two-party private set intersection protocol based on re-encryption is proposed,which preliminarily realizes privacy protection and verifiable computation results.Specifically,the user first expands a single subset into multiple subsets,and implicitly embeds a label set for each subset,and only performs the intersection computation on the subsets with the same label.Therefore,fine-grained operations are realized,which is beneficial to broaden practical application value of the protocol.Secondly,the user encrypts the set elements using the re-encryption technology,and the cloud server calculates the intersection of the set on the re-encrypted ciphertext.During this process,no plaintext information about the user data can be obtained,thereby realizing privacy protection.Finally,the user verifies whether the computation result is correct by judging whether the algebraic equation of the co-prime of the polynomials is established,so as to realize the unforgeability of the intersection computation results.(2)Multi-party private set intersection protocol based on pseudo-random functionOn the basis of the two-party private set intersection protocol to achieve verifiably,antileakage and other security properties,the protocol is further extended to multi-party computation.Therefore,a multi-party private set intersection protocol based on pseudo-random function is proposed,which aims to resist collusion attacks,protect user privacy and ensure the correctness of the computation results.Specifically,users construct pseudo-random functions and use oblivious key-value storage to encode elements,and only retain the mapping relationship of key-value pairs to prevent privacy leakage caused by collusion attacks between cloud servers and users.Secondly,the user can verify the computation results by judging whether the intersection is within the valid range by copying the set elements and inserting the virtual set.Finally,symmetric encryption and lightweight XOR operations are used to reduce computational overhead and performance analysis demonstrates that the protocol is efficient.