Applicability of Squeezed- and Coherent-State Continuous-Variable Quantum Key Distribution over Satellite Links
Department of Optics, Palacky University, 771 46 Olomouc, Czech Republic
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Author to whom correspondence should be addressed.
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These authors contributed equally to this work.
Entropy 2021, 23(1), 55; https://doi.org/10.3390/e23010055
Received: 13 December 2020 / Revised: 27 December 2020 / Accepted: 29 December 2020 / Published: 31 December 2020
(This article belongs to the Special Issue Quantum Cryptography II)
We address the applicability of quantum key distribution with continuous-variable coherent and squeezed states over long-distance satellite-based links, considering low Earth orbits and taking into account strong varying channel attenuation, atmospheric turbulence and finite data ensemble size effects. We obtain tight security bounds on the untrusted excess noise on the channel output, which suggest that substantial efforts aimed at setup stabilization and reduction of noise and loss are required, or the protocols can be realistically implemented over satellite links once either individual or passive collective attacks are assumed. Furthermore, splitting the satellite pass into discrete segments and extracting the key from each rather than from the overall single pass allows one to effectively improve robustness against the untrusted channel noise and establish a secure key under active collective attacks. We show that feasible amounts of optimized signal squeezing can substantially improve the applicability of the protocols allowing for lower system clock rates and aperture sizes and resulting in higher robustness against channel attenuation and noise compared to the coherent-state protocol.
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Keywords:
quantum cryptography; quantum optics; quantum key distribution; continuous variables; coherent states; squeezed states; satellite; low Earth orbit
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MDPI and ACS Style
Derkach, I.; Usenko, V.C. Applicability of Squeezed- and Coherent-State Continuous-Variable Quantum Key Distribution over Satellite Links. Entropy 2021, 23, 55. https://doi.org/10.3390/e23010055
AMA Style
Derkach I, Usenko VC. Applicability of Squeezed- and Coherent-State Continuous-Variable Quantum Key Distribution over Satellite Links. Entropy. 2021; 23(1):55. https://doi.org/10.3390/e23010055
Chicago/Turabian StyleDerkach, Ivan; Usenko, Vladyslav C. 2021. "Applicability of Squeezed- and Coherent-State Continuous-Variable Quantum Key Distribution over Satellite Links" Entropy 23, no. 1: 55. https://doi.org/10.3390/e23010055
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