Multi-keyword privacy query for outsourced data in cloud environments

This paper presents a quantum cryptography technology and proposes a practical quantum scheme designed to address the challenge of multi-keyword privacy queries in outsourced data. This scheme completes the privacy query by utilizing the secure two-party computing set similarity protocol, secure two-party quantum logic multiplication protocol, and quantum privacy query protocol that we developed. These mechanisms can ensure the security of data stored remotely in the cloud and preserve the privacy of the query condition. Both the secure two-party computing set similarity and quantum logic multiplication protocols achieve information-theoretical security with the assistance of a noncolluding quantum cloud. Moreover, the quantum privacy query protocol is designed to withstand quantum attacks, thereby ensuring the security within the proposed scheme is quantum secure. Furthermore, all basic protocols employ single photons as quantum resources, with the Toffoli gate representing the most complex operation and single-photon measurement constituting the required measurement. Therefore, this scheme is practical and feasible under existing technical conditions. Finally, we validated the accuracy and feasibility of the key links of this scheme on IBM's quantum system using Qiskit.