Differential Phase Shift Quantum Secret Sharing Using a Twin Field with Asymmetric Source Intensities

TL;DR

This paper introduces an improved differential phase shift quantum secret sharing protocol with asymmetric source intensities, significantly enhancing key rates and robustness over asymmetric channels, advancing practical quantum cryptography applications.

Contribution

The paper develops a novel asymmetric protocol with security proof and demonstrates its superior performance over existing methods in realistic conditions.

Findings

Key rate two orders of magnitude higher than original protocol

High robustness against finite-key effects

Effective over channels with large asymmetry

Abstract

As an essential application of quantum mechanics in classical cryptography, quantum secret sharing has become an indispensable component of quantum internet. Recently, a differential phase shift quantum secret sharing protocol using a twin field has been proposed to break the linear rate-distance boundary. However, this original protocol has a poor performance over channels with asymmetric transmittances. To make it more practical, we present a differential phase shift quantum secret sharing protocol with asymmetric source intensities and give the security proof of our protocol against individual attacks. Taking finite-key effects into account, our asymmetric protocol can theoretically obtain the key rate two orders of magnitude higher than that of the original protocol when the difference in length between Alice's channel and Bob's is fixed at 14 km. Moreover, our protocol can provide a high key rate even when the difference is quite large and has great robustness against finite-key effects. Therefore, our work is meaningful for the real-life applications of quantum secret sharing.