Deploying and validating a metropolitan QKD secure network: architecture and field performance

Claudia De Lazzari; Nicola Biagi; Damiano Giani; Marco Russo; Fernando Chirici; Francesco Stocco; Saverio Francesconi; Giacomo Ferranti; Alessandro Soureal; Antonella Sanguineti; Bartolomeo Montrucchio; Christian Laurenzi; Oliviero Testa; Guglielmo Morgari; Antonio Manzalini; Tommaso Occhipinti; Alessandro Zavatta; Davide Bacco

arXiv · 2607.11727

Deploying and validating a metropolitan QKD secure network: architecture and field performance

Claudia De Lazzari·Nicola Biagi·Damiano Giani·Marco Russo·Fernando Chirici·Francesco Stocco·Saverio Francesconi·Giacomo Ferranti·Alessandro Soureal·Antonella Sanguineti·Bartolomeo Montrucchio·Christian Laurenzi·Oliviero Testa·Guglielmo Morgari·Antonio Manzalini·Tommaso Occhipinti·Alessandro Zavatta·Davide Bacco

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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.

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BibTeX RIS

Claudia De Lazzari, Nicola Biagi, Damiano Giani, Marco Russo, Fernando Chirici, Francesco Stocco, Saverio Francesconi, Giacomo Ferranti, Alessandro Soureal, Antonella Sanguineti, Bartolomeo Montrucchio, Christian Laurenzi, Oliviero Testa, Guglielmo Morgari, Antonio Manzalini, Tommaso Occhipinti, Alessandro Zavatta, Davide Bacco. 2026-07-13. Deploying and validating a metropolitan QKD secure network: architecture and field performance. https://arxiv.org/abs/2607.11727

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