Quantum Key Distribution in the Iberian Peninsula

• URL: http://arxiv.org/abs/2510.12951v1
• Date: Tue, 14 Oct 2025 19:55:36 GMT
• Title: Quantum Key Distribution in the Iberian Peninsula
• Authors: Vicky Domínguez Tubío, Mario Badás Aldecocea, David L. Bakker, Gustavo C. Amaral, Diego López, Johannes Borregaard,
• Abstract summary: Quantum key distribution (QKD) provides information-theoretic security unattainable by classical means.<n>We propose and evaluate a satellite-based QKD setup linking Madrid with Barcelona, Bilbao, and Lisbon.<n>Our results show that key rates sufficient for real-world applications, such as secure communication between hospitals, are feasible with existing protocols.
• Score: 0.0
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: A promising use of quantum networking is quantum key distribution (QKD), which can provide information-theoretic security unattainable by classical means. While optical fiber-based QKD networks suffer from exponential loss, satellite-assisted quantum communication offers a scalable solution for long-distance secure key exchange. In this work, we propose and evaluate a satellite-based QKD setup covering the Iberian Peninsula, linking Madrid with Barcelona, Bilbao, and Lisbon. Our proposed setup uses a Low-Earth-Orbit (LEO) state-of-the-art satellite equipped with a spontaneous parametric down-conversion (SPDC) source to distribute entangled photon pairs to ground stations. Considering vibrations in the satellite, we optimize the beam waist to enhance the transmission probability and improve the secret key rate (SKR). Our results show that key rates sufficient for real-world applications, such as secure communication between hospitals, using hybrid classical-quantum protocols are feasible with existing protocols. Our results highlight the viability of near-term satellite-based QKD networks for national-scale secure communications.

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