Quantum Multi-Party Private Set Intersection Using Single Photons

Multi-party private set intersection (MP-PSI), an essential branch of secure multiparty computation (SMC), enables multiple users to collaboratively determine the intersection of their private sets without revealing any private information except for the set intersection. Although MP-PSI has many practical applications, none of the existing MP-PSI protocols are quantum-proof security. Compared to classical and post-quantum cryptography, quantum cryptography, which relies on quantum mechanics, can provide a superior solution to resist various quantum attacks and achieve quantum-proof security. In this paper, we propose a multi-party quantum private set intersection (MP-QPSI) protocol, which can compute the set intersection with one protocol execution. The proposed protocol can not only keep the private sets undisclosed to the participants and third party (TP), but also prevent external attacks from outsider eavesdroppers. It utilizes easy-to-implement technologies such as single photons, single-particle measurements, and rotation operations. To validate the feasibility of the proposed protocol, a quantum circuit for the simulation experiment is designed and executed on IBM Quantum Experience. Compared to previous studies, our protocol demonstrates improved performance in terms of security and feasibility.