Multiparty Quantum Private Comparsion with Individually Dishonest Third Parties for Strangers

TL;DR

This paper introduces a novel quantum private comparison protocol with two third parties, enabling strangers to securely compare secrets and detect fraudulent results, thus enhancing trustworthiness in quantum comparisons.

Contribution

A new quantum private comparison protocol with dual third parties is proposed, allowing fraud detection and enabling strangers to securely compare secrets.

Findings

Participants can detect fake comparison results immediately.

The protocol allows strangers to compare secrets privately.

Enhanced trustworthiness in quantum private comparison protocols.

Abstract

This study explores a new security problem existing in various state-of-the-art quantum private comparison (QPC) protocols, where a malicious third-party (TP) announces fake comparison (or intermediate) results. In this case, the participants could eventually be led to a wrong direction and the QPC will become fraudulent. In order to resolve this problem, a new level of trustworthiness for TP is defined and a new QPC protocol is proposed, where a second TP is introduced to monitor the first one. Once a TP announces a fake comparison (or intermediate) result, participants can detect the fraud immediately. Besides, due to the introduction of the second TP, the proposed protocol allows strangers to compare their secrets privately, whereas the state-of-the-art QPCs require the involved clients to know each other before running the protocol.