Experimental coherent-state quantum secret sharing with finite pulses

TL;DR

This paper presents a practical three-user quantum secret sharing protocol using phase encoding, ensuring security against coherent attacks in finite-key regimes and validated over 5 km fiber with secure key rates up to 432 bps.

Contribution

The work introduces a novel three-user QSS protocol with symmetric basis procedures, addressing security loopholes and demonstrating practicality in real optical fiber systems.

Findings

Secure key rates from 432 to 192 bps under finite-key conditions.

Validated protocol over 5 km fiber with 30-dB channel loss.

Enhanced security against coherent attacks using Kato's concentration inequality.

Abstract

Quantum secret sharing (QSS) plays a significant role in multiparty quantum communication and is a crucial component of future quantum multiparty computing networks. Therefore, it is highly valuable to develop a QSS protocol that offers both information-theoretic security and validation in real optical systems under a finite-key regime. In this work, we propose a three-user QSS protocol based on phase-encoding technology. By adopting symmetric procedures for the two players, our protocol resolves the security loopholes introduced by asymmetric basis choice without prior knowledge of the identity of the malicious player. Kato's concentration inequality is exploited to provide security against coherent attacks with the finite-key effect. Moreover, the practicality of our protocol has been validated under a 30-dB channel loss with a transmission distance of 5-km fiber. Our protocol achieves secure key rates ranging from 432 to 192 bps by choosing different pulse intensities and basis selection probabilities. Offering enhanced security and practicality, our protocol stands as an essential element for the realization of quantum multiparty computing networks.