Opaque Attack on Three-Party Quantum Secret Sharing Based on Entanglement

TL;DR

This paper analyzes the security vulnerabilities of three-party quantum secret sharing schemes based on entanglement, revealing they are insecure under high channel losses and proposing a method to enhance their security for sharing quantum states.

Contribution

It introduces an opaque attack on entanglement-based QSS schemes and proposes a general approach to improve their security against such attacks.

Findings

QSS schemes are insecure below 50% transmission efficiency

Opaque attack allows dishonest agents to eavesdrop freely

Proposed security enhancement improves robustness for sharing quantum states

Abstract

Security of the three-party quantum secret sharing (QSS) schemes based on entanglement and a collective eavesdropping check is analyzed in the case of considerable quantum channel losses. An opaque attack scheme is presented for the dishonest agent to eavesdrop the message obtained by the other agent freely, which reveals that these QSS schemes are insecure for transmission efficiencies lower than 50%, especially when they are used to share an unknown quantum state. Finally, we present a general way to improve the security of QSS schemes for sharing not only a private key but also an unknown quantum state.