Random Variation of Detector Efficiency: A Countermeasure against Detector Blinding Attacks for Quantum Key Distribution

TL;DR

This paper proposes a countermeasure for quantum key distribution systems against detector blinding attacks by randomly varying detector efficiency, aiming to enhance security against side-channel exploits.

Contribution

It introduces a practical method of randomly varying detector efficiency to mitigate detector blinding attacks in quantum key distribution.

Findings

Random efficiency variation reduces vulnerability to blinding attacks

Experimental validation shows improved security without increasing error rates

Method is feasible with current quantum communication technology

Abstract

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.