Finite-size security of continuous-variable quantum key distribution with digital signal processing

In comparison to conventional discrete-variable (DV) quantum key distribution (QKD), continuous-variable (CV) QKD with homodyne/heterodyne measurements has distinct advantages of lower-cost implementation and affinity to wavelength division multiplexing. On the other hand, its continuous nature make...

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Bibliographic Details
Published inarXiv.org
Main Authors Matsuura, Takaya, Maeda, Kento, Sasaki, Toshihiko, Koashi, Masato
Format Paper Journal Article
LanguageEnglish
Published Ithaca Cornell University Library, arXiv.org 08.06.2020
Subjects
Continuity (mathematics)
Digital signal processing
Physics - Quantum Physics
Quantum cryptography
Security
Signal processing
Wavelength division multiplexing
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Summary:In comparison to conventional discrete-variable (DV) quantum key distribution (QKD), continuous-variable (CV) QKD with homodyne/heterodyne measurements has distinct advantages of lower-cost implementation and affinity to wavelength division multiplexing. On the other hand, its continuous nature makes it harder to accommodate to practical signal processing, which is always discretized, leading to lack of complete security proofs so far. Here we propose a tight and robust method of estimating fidelity of an optical pulse to a coherent state via heterodyne measurements. We then construct a binary phase modulated CV QKD protocol and prove its security in the finite-key-size regime against general coherent attacks, based on proof techniques of DV QKD. Such a complete security proof achieves a significant milestone in exploiting the benefits of CV QKD.
ISSN:2331-8422
DOI:10.48550/arxiv.2006.04661