Deploying and validating a metropolitan QKD secure network: architecture and field performance
Abstract
The advent of cryptographically relevant quantum computers poses an existential threat to classical public-key infrastructure. Quantum Key Distribution (QKD) addresses this challenge by providing information-theoretic security for key establishment, independently of any computational hardness assumption. In this work, the deployment and experimental validation of a metropolitan-scale quantum-secure network between data centers in Milan is reported. The network operates over installed fiber infrastructure and implements a layered architecture integrating QKD hardware, standards-compliant Key Management (KM), and centralized Software-Defined Networking (SDN) orchestration. Dynamic path reconfiguration via active optical switching and trusted-node routing allow automated fail-over solutions. Application-layer validation across diverse protocols and workloads confirms the seamless interoperability of all system components. These results establish the technical and operational readiness of metropolitan QKD networks for production deployment, and offer a replicable blueprint for building quantum-secure communication infrastructure at metropolitan scale.
Cite
@article{arxiv.2607.11727,
title = {Deploying and validating a metropolitan QKD secure network: architecture and field performance},
author = {Claudia De Lazzari and Nicola Biagi and Damiano Giani and Marco Russo and Fernando Chirici and Francesco Stocco and Saverio Francesconi and Giacomo Ferranti and Alessandro Soureal and Antonella Sanguineti and Bartolomeo Montrucchio and Christian Laurenzi and Oliviero Testa and Guglielmo Morgari and Antonio Manzalini and Tommaso Occhipinti and Alessandro Zavatta and Davide Bacco},
journal= {arXiv preprint arXiv:2607.11727},
year = {2026}
}