Towards National Quantum Communication in Europe: Planning and Sizing Terrestrial QKD Networks

2026-04-08

AI Summary

This study addresses the challenge of planning national-scale terrestrial quantum key distribution (QKD) networks to secure critical infrastructure communications across European countries. It proposes a reproducible estimation framework grounded in a minimal set of explicit assumptions, integrating synthetic network modeling, Monte Carlo simulations, trusted-node relay analysis, and hop-length distribution. Using Austria as a case study, the authors develop a structured model and derive scalable cross-national extrapolation rules applicable to EU member states. The work provides the first-order estimates for EuroQCI-aligned national QKD backbone deployments, including required numbers of nodes, total fiber length, and core component counts, thereby enabling preliminary cost assessments and informed infrastructure planning.

Abstract

The European Union is developing the European Quantum Communication Infrastructure (EuroQCI) as a pan-European network to provide secure communication capabilities across Member States, including governmental and critical-infrastructure domains. While the strategic objective is defined at EU level, the required scale and structure of national quantum key distribution (QKD) networks remain largely unspecified. This work addresses the question of how to plan and size national terrestrial QKD networks to support critical infrastructure and public authorities. We propose a reproducible planning methodology that estimates network size, total fiber length, and the number of required QKD components based on a small set of explicit assumptions. The approach is demonstrated for Austria, where a synthetic but structured network model is constructed and evaluated using Monte Carlo simulation. The model focuses on terrestrial QKD infrastructure and explicitly excludes space-based segments. It estimates endpoint counts, trusted repeater node requirements, and hop-length distributions under realistic operational constraints. The Austrian case is then used as a baseline to derive scaling rules for other EU Member States based on population and geographic extent. The results provide first-order planning estimates for national QKD backbone sizes across Europe. These estimates are not intended as deployment designs but as planning-level references that support early-stage cost assessment and infrastructure dimensioning under the EuroQCI framework.

Problem

• Quantum Key Distribution
• National QKD Network
• Network Planning
• EuroQCI
• Critical Infrastructure

Innovation

• Quantum Key Distribution (QKD)
• Network Planning
• EuroQCI
• Trusted Repeater
• Monte Carlo Simulation