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arXiv · 1509.08137

Quantum cryptography without detector vulnerabilities using optically-seeded lasers

L. C. Comandar·M. Lucamarini·B. Fröhlich·J. F. Dynes·A. W. Sharpe·S. Tam·Z. L. Yuan·R. V. Penty·A. J. Shields
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Abstract

Security in quantum cryptography is continuously challenged by inventive attacks targeting the real components of a cryptographic setup, and duly restored by new counter-measures to foil them. Due to their high sensitivity and complex design, detectors are the most frequently attacked components. Recently it was shown that two-photon interference from independent light sources can be exploited to avoid the use of detectors at the two ends of the communication channel. This new form of detection-safe quantum cryptography, called Measurement-Device-Independent Quantum Key Distribution (MDI-QKD), has been experimentally demonstrated, but with modest delivered key rates. Here we introduce a novel pulsed laser seeding technique to obtain high-visibility interference from gain-switched lasers and thereby perform quantum cryptography without detector vulnerabilities with unprecedented bit rates, in excess of 1 Mb/s. This represents a 2 to 6 orders of magnitude improvement over existing implementations and for the first time promotes the new scheme as a practical resource for quantum secure communications.

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L. C. Comandar, M. Lucamarini, B. Fröhlich, J. F. Dynes, A. W. Sharpe, S. Tam, Z. L. Yuan, R. V. Penty, A. J. Shields. 2015-10-01. Quantum cryptography without detector vulnerabilities using optically-seeded lasers. https://doi.org/10.1038/nphoton.2016.50

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