Efficient Multiparty Quantum Key Distribution over Quantum Networks

TL;DR

This paper introduces efficient strategies for multiparty quantum key distribution over quantum networks, optimizing secret key rates by packing multiple entanglement structures, and demonstrates their effectiveness through extensive evaluations.

Contribution

It develops novel methods for N-party QKD by packing multiple trees and stars, directly incorporating network key rates, to maximize secret key generation.

Findings

Achieves high secret key rates in various network topologies.

Key rate degrades gracefully with increasing number of parties.

Strategies outperform existing approaches in simulations.

Abstract

Multiparty quantum key distribution (QKD) is useful for many applications that involve secure communication or collaboration among multiple parties. While it can be achieved using pairwise QKD, a more efficient approach is to achieve it using multipartite entanglement distributed over quantum networks that connect the multiple parties. Existing studies on multipartite entanglement distribution, however, are not designed for multiparty QKD, and hence do not aim to maximize secret key generation rate. In this paper, we design efficient strategies for multiparty QKD over quantum networks. For 3-party QKD, we derive closed-form expressions for analyzing key distribution over quantum networks. We then use it to develop an efficient strategy for 3-party QKD by packing multiple stars that connect the 3 parties. For the general form of N-party QKD, we develop an approach that packs multiple trees to connect the N parties, while directly incorporating the estimated key rates on network paths. Extensive evaluation of our strategies, in both grid and random graphs, under a wide range of settings, demonstrates that our schemes achieve high key rate, which degrades gracefully when increasing the number of parties.