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arXiv · 1208.0532

Real-time monitoring of single-photon detectors against eavesdropping in quantum key distribution systems

T. Ferreira da Silva·G. B. Xavier·G. P. Temporão·J. P. von der Weid
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Abstract

By employing real-time monitoring of single-photon avalanche photodiodes we demonstrate how two types of practical eavesdropping strategies, the after-gate and time-shift attacks, may be detected. Both attacks are identified with the detectors operating without any special modifications, making this proposal well suited for real-world applications. The monitoring system is based on accumulating statistics of the times between consecutive detection events, and extracting the afterpulse and overall efficiency of the detectors in real-time using mathematical models fit to the measured data. We are able to directly observe changes in the afterpulse probabilities generated from the after-gate and faint after-gate attacks, as well as different timing signatures in the time-shift attack. We also discuss the applicability of our scheme to other general blinding attacks.

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T. Ferreira da Silva, G. B. Xavier, G. P. Temporão, J. P. von der Weid. 2012-08-02. Real-time monitoring of single-photon detectors against eavesdropping in quantum key distribution systems. https://doi.org/10.1364/oe.20.018911

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