Breaking Rate-Distance Limitation of Measurement-Device-Independent Quantum Secret Sharing

TL;DR

This paper introduces a measurement-device-independent quantum secret sharing protocol that significantly enhances key rate and transmission distance, overcoming previous rate-distance bounds and enabling scalable multiparty quantum networks.

Contribution

The authors propose a novel protocol based on spatial multiplexing that breaks rate-distance bounds and improves secret key rate by over two orders of magnitude, with security analysis including participant attacks.

Findings

Over ten parties in a network can achieve improved rate-distance performance.

Secret key rate is increased by more than 100 times compared to existing protocols.

Applying the protocol to digital signatures yields a rate improvement of over 10^7.

Abstract

Currently most progresses on quantum secret sharing suffer from rate-distance bound, and thus the key rates are limited. In addition to the limited key rate, the technical difficulty and the corresponding cost together prevent large-scale deployment. Furthermore, the performance of most existing protocols is analyzed in the asymptotic regime without considering participant attacks. Here we report a measurement-device-independent quantum secret sharing protocol with improved key rate and transmission distance. Based on spatial multiplexing, our protocol shows it can break rate-distance bounds over network under at least ten communication parties. Compared with other protocols, our work improves the secret key rate by more than two orders of magnitude and has a longer transmission distance. We analyze the security of our protocol in the composable framework considering participant attacks and evaluate its performance in the finite-size regime. In addition, we investigate applying our protocol to digital signatures where the signature rate is improved more than $10^7$ times compared with existing protocols. We anticipate that our quantum secret sharing protocol will provide a solid future for multiparty applications on the quantum network.