In the recent decade, it has been discovered that QKD systems are extremely vulnerable to side-channel attacks. In particular, by exploiting the internal working knowledge of practical detectors, it is possible to bring them to an operating region whereby only certain target detectors are sensitive to detections. Crucially, the adversary can use this loophole to learn everything about the secret key without introducing any error to the quantum channel. In this work, as a step towards overcoming detector blinding attacks, we focus on an experimentally convenient countermeasure, where the efficiency of the detectors is randomly varied.
@article{arxiv.1408.6398,
title = {Random Variation of Detector Efficiency: A Countermeasure against Detector Blinding Attacks for Quantum Key Distribution},
author = {Charles Ci Wen Lim and Nino Walenta and Matthieu Legre and Nicolas Gisin and Hugo Zbinden},
journal= {arXiv preprint arXiv:1408.6398},
year = {2015}
}