Repeater-like asynchronous measurement-device-independent quantum conference key agreement

TL;DR

This paper introduces a novel asynchronous measurement-device-independent quantum conference key agreement protocol that enables scalable, secure, and efficient multipartite quantum communication over long distances without complex phase locking.

Contribution

It proposes a new asynchronous protocol for quantum conference key agreement that simplifies implementation and achieves performance comparable to single-repeater schemes.

Findings

Linear scaling of conference key rate among multiple parties

Achieves intercity transmission with composable security under finite-key conditions

Eliminates the need for complex global phase locking techniques

Abstract

Quantum conference key agreement enables secure communication among multiple parties by leveraging multipartite entanglement, which is expected to play a crucial role in future quantum networks. However, its practical implementation has been severely limited by the experimental complexity and low efficiency associated with the requirement for synchronous detection of multipartite entangled states. In this work, we propose a measurement-device-independent quantum conference key agreement protocol that employs asynchronous Greenberger-Horne-Zeilinger state measurement. Our protocol enables a linear scaling of the conference key rate among multiple parties, demonstrating performance comparable to that of the single-repeater scheme in quantum networks. Additionally, we achieve intercity transmission distances with composable security under finite-key conditions. By adopting the generalized asynchronous pairing strategy, our approach eliminates the need for complex global phase locking techniques. Furthermore, by integrating asynchronous pairing with ring-interference network structure, our method provides insights for various quantum tasks beyond quantum communication, including multiparty computing and quantum repeaters.