A novel quantum private query protocol and its application in private set intersection

As an important topic in quantum secure multiparty computing, quantum privacy query (QPQ) can solve the problem of information query between users and database owners without compromising privacy. In the existing research, most of them focus on its functions, not its applications. In this paper, a new QPQ protocol based on two-particle states is proposed. In our protocol, we use two-particle states combined with the Ctrl or Shift operations to give the user a partial key sequence and the database cannot recognize the user's key sequence. Meanwhile, we conduct simulation experiments at the IBM quantum experience and show that it is feasible. We discuss its application in the private set intersection (PSI), which is derived from QPQ. According to our analysis, the QPQ protocol and PSI protocol are secure.