Optimization of Information Reconciliation for Decoy-State Quantum Key Distribution over a Satellite Downlink Channel

Fuente: arXiv
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Main Authors: Scarinzi, Thomas, Orsucci, Davide, Ferrari, Marco, Barletta, Luca
Format: Preprint
Published: 2025
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author Scarinzi, Thomas
Orsucci, Davide
Ferrari, Marco
Barletta, Luca
author_facet Scarinzi, Thomas
Orsucci, Davide
Ferrari, Marco
Barletta, Luca
contents Quantum key distribution (QKD) is a cryptographic solution that leverages the properties of quantum mechanics to be resistant and secure even against an attacker with unlimited computational power. Satellite-based links are important in QKD because they can reach distances that the best fiber systems cannot. However, links between satellites in low Earth orbit (LEO) and ground stations have a duration of only a few minutes, resulting in the generation of a small amount of secure keys. In this context, we investigate the optimization of the information reconciliation step of the QKD post-processing in order to generate as much secure key as possible. As a first step, we build an accurate model of the downlink signal and quantum bit error rate (QBER) during a complete satellite pass, which are time-varying due to three effects: (i) the varying link geometry over time, (ii) the scintillation effect, and (iii) the different signal intensities adopted in the Decoy-State protocol. Leveraging the a-priori information on the instantaneous QBER, we improve the efficiency of information reconciliation (IR) (i.e., the error correction phase) in the Decoy-State BB84 protocol, resulting in a secure key that is almost 3\% longer for realistic scenarios.
format Preprint
id arxiv_https___arxiv_org_abs_2511_05196
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Optimization of Information Reconciliation for Decoy-State Quantum Key Distribution over a Satellite Downlink Channel
Scarinzi, Thomas
Orsucci, Davide
Ferrari, Marco
Barletta, Luca
Quantum Physics
Cryptography and Security
Information Theory
Quantum key distribution (QKD) is a cryptographic solution that leverages the properties of quantum mechanics to be resistant and secure even against an attacker with unlimited computational power. Satellite-based links are important in QKD because they can reach distances that the best fiber systems cannot. However, links between satellites in low Earth orbit (LEO) and ground stations have a duration of only a few minutes, resulting in the generation of a small amount of secure keys. In this context, we investigate the optimization of the information reconciliation step of the QKD post-processing in order to generate as much secure key as possible. As a first step, we build an accurate model of the downlink signal and quantum bit error rate (QBER) during a complete satellite pass, which are time-varying due to three effects: (i) the varying link geometry over time, (ii) the scintillation effect, and (iii) the different signal intensities adopted in the Decoy-State protocol. Leveraging the a-priori information on the instantaneous QBER, we improve the efficiency of information reconciliation (IR) (i.e., the error correction phase) in the Decoy-State BB84 protocol, resulting in a secure key that is almost 3\% longer for realistic scenarios.
title Optimization of Information Reconciliation for Decoy-State Quantum Key Distribution over a Satellite Downlink Channel
topic Quantum Physics
Cryptography and Security
Information Theory
url https://arxiv.org/abs/2511.05196