Region Limited Outsourcing Private Set Intersection

Private set intersection(PSI)is an essential cryptographic protocol that has many real world applications.As cloud computing power and popularity have been swiftly growing,it is desirable to leverage the cloud to store private datasets and delegate PSI computation to it.Although a set of efficient PSI protocols have been designed,none of them supports outsourced datasets,cloud computing,and zoning.However,designing a reliable and efficient private set intersection protocol under data outsourcing still faces many problems:(1)How to provide an authorized computing environment with complete data outsourcing.In traditional PSI protocol,each party has full control over their own dataset.In data outsourcing PSI protocol,the dataset is outsourced and the client has to delegate its control to the cloud server.Therefore,an enforceable authorization mechanism needs to be established to ensure that computations can only take place with the consent of all data owners.(2)How to provide location verification in the PSI protocol where client data is completely outsourced.Because the existing data outsourcing PSI protocol does not provide location verification,it is impossible to limit the region where the client is located.(3)In the PSI protocol in which client data is completely outsourced,how to ensure the security of outsourced data and PSI calculation.Because cloud servers infer information about set elements and intersections over time.Therefore,it is necessary to ensure that the cloud server cannot obtain the data in the collection and the calculation results during the PSI calculation process.Combined with the existing technology,this thesis first designs a privacy-preserving set intersection protocol that supports distance limitation under client-side data outsourcing,which provides a secure data outsourcing private set intersection calculation while realizing distance limitation.Aiming at the security requirement of complete outsourcing of client data,this thesis constructs a system model that supports distance-limited private set intersection protocol under client data outsourcing,designs an adversary model of the protocol,and proposes the design goals that the protocol should meet.In order to realize the PSI calculation of distance limitation and data outsourcing,this protocol adopts the distance limitation protocol,so that the cloud server can verify whether the location of the client satisfies the distance limitation and outsource the data to the cloud server.Using a set of point-valued polynomials ensures that PSI calculations can only be performed if both clients are authorized.Finally,this protocol uses additive homomorphic encryption algorithm to ensure outsourced data security and PSI computing security.Then,this thesis proposes an efficient private set intersection protocol that supports region verification under data outsourcing,and limits the region where the client is located under the premise of limiting the distance between the client.Aiming at the system model and adversary model of an efficient outsourced private set intersection protocol based on region verification,the design goals of this protocol are proposed.And introduced the zone authentication protocol in the protocol,which completed the limitation of the client’s zone.At the same time,it changes the way that client data outsourcing hides its polynomial,and does not use any public key encryption with high computational cost.The client can decompose its original polynomial into a smaller degree polynomial,find the roots of the polynomial faster,and improve the efficiency of PSI calculation.Finally,the security analysis of the two protocols proposed in this thesis is carried out,and the performance evaluation and analysis of the two protocols are carried out through the simulation test.The analysis results show that the outsourced privacy-preserving set intersection protocols designed in this thesis all meet the corresponding design goals.At the same time,compared with related works,the protocol proposed in this thesis has higher security and better performance.