Dynamic Continuous Variable Quantum Key Distribution for Securing a Future Global Quantum Network

TL;DR

This paper explores the design and analysis of a global quantum network utilizing continuous variable quantum key distribution (CVQKD), focusing on network architecture, link performance, and dynamic routing for secure communication.

Contribution

It introduces a three-layer QKD network architecture, evaluates CVQKD link performance across various channels, and proposes a dynamic routing metric for secret key distribution in a global quantum network.

Findings

CVQKD achieves longer distances and higher SKRs in satellite and underwater links.

A graph-based model for secret key distribution was developed.

A dynamic routing metric improves secret key distribution efficiency.

Abstract

Continuous variable quantum key distribution (CVQKD) is a developing method to secure information exchange in future quantum networks. With the recent developments in quantum technology and greater access to space, a global quantum network secured by CVQKD could be within reach. In this work, the structures of existing QKD networks are analysed, and how they can be fit into a general overarching three-layer QKD network architecture for the endeavour of a global QKD network. Such a network could comprise of different links in fibre and free-space. The finite size limit secret key rates (SKRs) with multidimensional reconciliation were calculated for the different links for which CVQKD can be used in such a network. The results show that CVQKD generally achieves longer distances and larger SKRs in inter-satellite, satellite-to-ground, fibre, and underwater links in descending order. The different links and nodes were classified and secret key distribution was studied as a graph problem. The link capacity, a routing metric for secret key distribution, which considers a dynamic SKR based on dynamic links is presented. Its use in simulated CVQKD networks is presented for the aim of spatiotemporal secret key distribution through a dynamic CVQKD network.