Quantum private query with authentication

The quantum privacy query (QPQ) is the quantum version of private query, which refers to that a user (Alice) to purchase data from a database owner (Bob) under the condition of ensuring the privacy of both parties. Specifically, Alice should not access data other than those she bought, and Bob cannot know what data Alice has obtained. The existing QPQ protocols focus on privacy protection and ignore other attacks from outside attackers, such as impersonation, man-in-the-middle and tampering. Undoubtedly, these attacks can destroy the QPQ process. In this paper, we present a secure QPQ protocol that can resist external active attacks. By designing an identity authentication mechanism and integrating it into the existing quantum key distribution-based QPQ protocol, the proposed protocol implements mutual identity authentication in the oblivious key agreement phase to resist impersonation and “man-in-the-middle” attacks. Besides, the mutual authentication process also generates a shared key between Alice and Bob to achieve the data source authentication and integrity protection against tampering attack in the data retrieval phase. The security analysis demonstrates that the proposed protocol not only retains the privacy protection strength of the original QPQ protocol, but also has strong resistance to external attacks.