Private set intersection(PSI) enables parties to compute the intersection of their input sets privately, which has wide applications. Nowadays, with the development of cloud computing, several server-aided PSI protocols have been proposed. Unfortunately, all existing server-aided PSI protocols assume the server provider does not collude with any user and all the parties use the same encryption key, which have two main disadvantages: one is the protocols require user interaction to agree on a random key; the other is once one party is successfully attacked, all communications are compromised.In this work, we propose a two-server-aided PSI protocol under multiple keys, combining symmetric key proxy re-encryption (SKPRE) firstly introduced by Boneh etal. (CREPTO 2013) and social reputation system. By using two-server-aided model and SKPRE, our protocol can be suitable for multiparty set intersection, and each party uses a different key for encryption which is more secure than previous server-aided schemes. To prevent collusion, we assume each party has a reputation value updated according to his behavior in the current PSI protocol. The parties who defect the PSI protocol will be penalized for stimulating them to be cooperative and foresighted. Finally the protocol can be computed with complete fairness.Moreover, the protocol does not require public key infrastructures, eliminates user interaction and can outsource expensive computation from a weak computational client to a powerful server, which is suitable for mobile cloud computing.
['En Zhang', 'Fenghua Li', 'Ben Niu', 'Yanchao Wang']
Server-aided private set intersection based on reputation