Researches On Private Set Intersection Computation Protocols Under The Cloud Environments

Secure Multi-Party Computation(MPC or SMC)is a general cryptographic prim-itive,which is a technique that allows distributed participants to cooperatively compute arbitrary functions while outputting correct computation results without revealing the input information of the participants,and is one of the current research hotspots in the se-curity field.As one of the main research directions of SMC,the Private Set Intersection(PSI)protocol has many applications in production life,such as fast screening of new crowns,fast matching of users’ address books,calculation of advertising effectiveness,gene sequence matching,etc.The PSI protocol can ensure that each participant can ob-tain the intersection set without revealing their own privacy set.The PSI protocol can ensure that each participant can obtain the intersection set without disclosing their own private set of data.At the same time,with the rapid development of technologies re-lated to cloud computing,PSI is also able to use cloud servers for computing.However,the current cloud-assisted PSI protocol has the following drawbacks: inefficiency,the set intersection information still needs to be stored locally,the PSI operation has to be performed again after each data update,and the intersection calculation cannot be fully delegated to the cloud.The purpose of this paper is to explore how the computational and storage functions of the cloud server can be utilized,and how the intersection com-putation can be safely implemented under untrustworthy scenarios without disclosing private information,covering the following research.· Design and implementation of a lightweight cloud-assisted privacy set intersection computation protocol ED-PSI,which consists of cryptographic tools such as OT extension protocol,OPRF,pseudo-random functions and heterodyne operations.Subsequently,in order to demonstrate the improvement of both computational and communication overheads of the protocol,simulation experiments are conducted using C++ code,in which Boost1.67,lib OTe library and MIRACL,a cryptographic library for multi-precision integers and rational numbers,are used.In addition,security proofs and correctness arguments of the protocol are given under a semi-honest model to ensure that the intersection set is obtained correctly.· Based on the above protocols to explore the ideal functionality of cloud servers,a functional cloud-assisted PSI protocol OA-PSI is given.The main feature of this protocol is the ability to perform different authentication operations for users with specific privileges and thus obtain the set intersection.This paper defines the concept of authentication types and gives specific mathematical expressions that sequentially guarantee the intersection calculation between users with differ-ent privileges.Finally,the correctness analysis and formal security proof of the protocol are given in detail to ensure that the protocol can correctly obtain the set intersection without compromising privacy.