{"ID":2844914,"CreatedAt":"2026-06-01T04:54:23.091178241Z","UpdatedAt":"2026-06-01T04:54:23.091178241Z","DeletedAt":null,"paper_url":"https://arxiv.org/abs/2511.05196","arxiv_id":"2511.05196","title":"Optimization of Information Reconciliation for Decoy-State Quantum Key Distribution over a Satellite Downlink Channel","abstract":"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.","short_abstract":"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, l...","url_abs":"https://arxiv.org/abs/2511.05196","url_pdf":"https://arxiv.org/pdf/2511.05196v1","authors":"[\"Thomas Scarinzi\",\"Davide Orsucci\",\"Marco Ferrari\",\"Luca Barletta\"]","published":"2025-11-07T12:32:01Z","proceeding":"quant-ph","tasks":"[\"quant-ph\",\"cs.CR\",\"cs.IT\"]","methods":"[]","has_code":false}