Koehler-Sidki, A, Dynes, James F, Paraiso, T K et al. (4 more authors) (2020) Backflashes from fast-gated avalanche photodiodes in quantum key distribution. Applied Physics Letters. 154001. ISSN 0003-6951
Abstract
InGaAs single-photon avalanche photodiodes (APDs) are key enablers for high-bit rate quantum key distribution. However, the deviation of such detectors from ideal models can open side-channels for an eavesdropper, Eve, to exploit. The phenomenon of backflashes, whereby APDs reemit photons after detecting a photon, gives Eve the opportunity to passively learn the information carried by the detected photon without the need to actively interact with the legitimate receiver, Bob. While this has been observed in slow-gated detectors, it has not been investigated in fast-gated APDs where it has been posited that this effect would be lessened. Here, we perform the first experiment to characterize the security threat that backflashes provide in a GHz-gated self-differencing APD using the metric of information leakage. We find that, indeed, the information leakage is lower than that reported for slower-gated detectors, and we show that its effect on the secure key rate is negligible. We also relate the rate of backflash events to the APD dark current, thereby suggesting that their origin is the InP multiplication region in the APD.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | Uploaded in accordance with the publisher’s self-archiving policy. Further copying may not be permitted; contact the publisher for details |
Dates: |
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Institution: | The University of York |
Academic Units: | The University of York > Faculty of Sciences (York) > Physics (York) |
Depositing User: | Pure (York) |
Date Deposited: | 27 Oct 2020 11:10 |
Last Modified: | 16 Oct 2024 17:02 |
Published Version: | https://doi.org/10.1063/1.5140548 |
Status: | Published |
Refereed: | Yes |
Identification Number: | 10.1063/1.5140548 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:167266 |