Identity-Based Symmetric Private Set Intersection

A private set intersection (PSI) protocol enables two parties to privately compute the intersection of their inputs. Most of its previous versions are unilateral, that is, only one party can learn the intersection and the other learns nothing. Many applications require that both parties can obtain the final result. What´s more, all of the previous PSI protocols are based on traditional PKI. In this paper, we first present the cryptographic primitive of identity-based symmetric private set intersection (IBSPSI) protocol and give the first construction. To get an efficient construction, we propose an identity-based proxyre-encryption scheme using combined public keys(IBR-CPK), which is the first identity-based proxy re-encryption without pairing. Our IBR-CPK scheme almost as efficient as traditional ECC. It is not only ensures the privacy of the information during the transmission process but also holds perfect additive homomorphism. The IBSPSI protocol that we construct based on IBR-CPK efficiently solves the unilateral PSI problem and simplifies the certificate management. We prove that our IBSPSI protocol achieves perfect privacy in the semi-honest model.