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

Mikhael Sayat

doi:10.1002/qute.202500135

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

2025-06-11

Mikhael Sayat *

Sebastian P. Kish

Ping Koy Lam

Nicholas J. Rattenbury

John Cater

DOI：10.1002/qute.202500135

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Abstract

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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 can be within reach. In this work, the structures of existing QKD networks are analyzed, and how they can be fit into a general overarching three-layer QKD network architecture for the endeavor of a global QKD network. Such a network can comprise different links in fiber and free-space. The finite size limit secret key rates (SKRs) with multidimensional reconciliation are 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, fiber, and underwater links in descending order. The different links and nodes are classified and secret key distribution is 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.

Keywords:

network routing

quantum communications

quantum networks

quantum key distribution