Finite-key Analysis for Quantum Conference Key Agreement with Asymmetric Channels

TL;DR

This paper introduces a high-efficiency quantum conference key agreement protocol for asymmetric channels, utilizing a send-or-not-sending twin-field scheme and finite-key analysis to enhance transmission distance and security.

Contribution

It proposes a novel tripartite QCKA protocol that removes symmetry constraints and provides a rigorous finite-key security proof for asymmetric channels.

Findings

Significantly improves conference key rates over asymmetric channels

Achieves longer transmission distances in quantum networks

Provides a composable security proof against general attacks

Abstract

As an essential ingredient of quantum networks, quantum conference key agreement (QCKA) provides unconditional secret keys among multiple parties, which enables only legitimate users to decrypt the encrypted message. Recently, some QCKA protocols employing twin-field was proposed to promote transmission distance. These protocols, however, suffer from relatively low conference key rate and short transmission distance over asymmetric channels, which demands a prompt solution in practice. Here, we consider a tripartite QCKA protocol utilizing the idea of sending-or-not-sending twin-field scheme and propose a high-efficiency QCKA over asymmetric channels by removing the symmetry parameters condition. Besides, we provide a composable finite-key analysis with rigorous security proof against general attacks by exploiting the entropic uncertainty relation for multiparty system. Our protocol greatly improves the feasibility to establish conference keys over asymmetric channels.