Greenberger-Horne-Zeilinger-based quantum private comparison protocol with bit-flipping

TL;DR

This paper introduces a GHZ-based quantum private comparison protocol utilizing bit-flipping and quantum key distribution, enhancing security and efficiency while reducing quantum technology requirements.

Contribution

The proposed protocol is novel in using (n+1)-qubit GHZ states with bit-flipping and decoy photons, improving security against various attacks and simplifying quantum device needs.

Findings

Secure against external intercept-resend and measurement-resend attacks

TP cannot steal participants' data or manipulate outcomes

Existing attack methods are ineffective against this protocol

Abstract

By introducing a semi-honest third party (TP), we propose in this paper a novel QPC protocol using (n+1)- qubit (n \ge 2) Greenberger-Horne-Zeilinger (GHZ) states as information carriers. The parameter n not only determines the number of qubits contained in a GHZ state, but also determines the probability that TP can successfully steal the participants' data and the qubit efficiency. In the proposed protocol, we do not employ any other quantum technologies (e.g., entanglement swapping and unitary operation) except necessary technologies such as preparing quantum states and quantum measurements, which can reduce the need for quantum devices. We use the keys generated by quantum key distribution and bit-flipping for privacy protection, and decoy photons for eavesdropping checking, making both external and internal attacks invalid. Specifically, for external attacks, we take several well-known attack means (e.g., the intercept-resend attack and the measurement-resend attack) as examples to show that the attackers outside the protocol can not steal the participants' data successfully, in which we provide the security proof of the protocol against the entanglement-measurement attack. For internal attacks, we show that TP cannot steal the participants' data and the participants cannot steal each other's data. We also show that the existing attack means against QPC protocols are invalid for our protocol.