Ghalaii, Masoud, Bahrani, Sima, Liorni, Carlo et al. (9 more authors) (2022) Realistic Threat Models for Satellite-Based Quantum Key Distribution. [Preprint]
Abstract
The security of prepare-and-measure satellite-based quantum key distribution (QKD), under restricted eavesdropping scenarios, is addressed. We particularly consider cases where the eavesdropper, Eve, has limited access to the transmitted signal by Alice, and/or Bob's receiver station. This restriction is modeled by lossy channels between Alice/Bob and Eve, where the transmissivity of such channels can, in principle, be bounded by monitoring techniques. An artefact of such lossy channels is the possibility of having bypass channels, those which are not accessible to Eve, but may not necessarily be characterized by the users either. This creates interesting, {\it unexplored}, scenarios for analyzing QKD security. In this paper, we obtain generic bounds on the key rate in the presence of bypass channels and apply them to continuous-variable QKD protocols with Gaussian encoding with direct and reverse reconciliation. We find regimes of operation in which the above restrictions on Eve can considerably improve system performance. We also develop customised bounds for several protocols in the BB84 family and show that, in certain regimes, even the simple protocol of BB84 with weak coherent pulses is able to offer positive key rates at high channel losses, which would otherwise be impossible under an unrestricted Eve. In this case the limitation on Eve would allow Alice to send signals with larger intensities than the optimal value under an ideal Eve, which effectively reduces the effective channel loss. In all these cases, the part of the transmitted signal that does not reach Eve can play a non-trivial role in specifying the achievable key rate. Our work opens up new security frameworks for spaceborne quantum communications systems.
Metadata
Item Type: | Preprint |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | 39 pages, 17 figures |
Keywords: | quant-ph |
Dates: |
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Institution: | The University of York |
Academic Units: | The University of York > Faculty of Sciences (York) > Computer Science (York) The University of York > Faculty of Sciences (York) > Physics (York) |
Depositing User: | Pure (York) |
Date Deposited: | 08 Jun 2023 23:19 |
Last Modified: | 01 Apr 2025 23:12 |
Published Version: | https://doi.org/10.48550/arXiv.2212.04807 |
Status: | Published |
Publisher: | arXiv |
Identification Number: | 10.48550/arXiv.2212.04807 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:200251 |