Optical control of single-photon negative-feedback avalanche diode detector

TL;DR

This paper demonstrates optical control over NFAD detectors using bright light, enabling fake detections with high timing precision and revealing potential security vulnerabilities in quantum cryptography systems.

Contribution

It introduces a method to optically manipulate NFAD detectors and proposes a monitoring technique to detect blinding attacks, highlighting security concerns.

Findings

Fake detections with improved timing precision

Detection of blinding attacks via photocurrent monitoring

Potential security loopholes in quantum cryptography

Abstract

We experimentally demonstrate optical control of negative-feedback avalanche diode (NFAD) detectors using bright light. We deterministically generate fake single-photon detections with a better timing precision than normal operation. This could potentially open a security loophole in quantum cryptography systems. We then show how monitoring the photocurrent through the avalanche photodiode can be used to reveal the detector is being blinded.