Backflashes in fast-gated avalanche photodiodes in quantum key distribution

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. Whilst 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 characterise 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 their origin is the InP multiplication region in the APD.

References in corpus (18)

• Quantum cryptography: Public key distribution and coin tossing
• Field test of quantum key distribution in the Tokyo QKD Network
• Hacking commercial quantum cryptography systems by tailored bright illumination
• Full-field implementation of a perfect eavesdropper on a quantum cryptography system
• Quantum cryptography without detector vulnerabilities using optically-seeded lasers
• Integrating quantum key distribution with classical communications in backbone fiber network
• Unconditional Security of Practical Quantum Key Distribution
• 10~Mb/s quantum key distribution
• Avoiding the Detector Blinding Attack on Quantum Cryptography
• Metropolitan quantum key distribution with silicon photonics
• The breakdown flash of Silicon Avalance Photodiodes - backdoor for eavesdropper attacks?
• GHz-gated InGaAs/InP single-photon detector with detection efficiency exceeding 55% at 1550 nm
• Resilience of gated avalanche photodiodes against bright illumination attacks in quantum cryptography
• Room temperature single-photon detectors for high bit rate quantum key distribution
• Backflash light characterization to prevent QKD zero-error hacking
• Eavesdropping and countermeasures for backflash side channel in quantum cryptography
• Integration of quantum key distribution and gigabit-capable passive optical network based on wavelength-division multiplexing
• Breakdown flash at telecom wavelengths in InGaAs avalanche photodiodes

Cited by in corpus (4)

• Preparing a commercial quantum key distribution system for certification against implementation loopholes
• Detection of ultra-weak laser pulses by free-running single-photon detectors: modeling dead time and dark counts effects
• Wide-spectrum security of quantum key distribution
• Backflash Attack on Coherent One-Way Quantum Key Distribution