Countermeasure against Detector Blinding Attack with Secret Key Leakage Estimation

TL;DR

This paper proposes a statistical countermeasure against detector blinding attacks in quantum key distribution, analyzing its effectiveness against pulsed DBA and enabling estimation of compromised bits.

Contribution

It extends previous countermeasures to pulsed DBA, demonstrating increased detection sensitivity and enabling estimation of adversarial impact.

Findings

Approximately 25 dB increase in trigger pulse energy difference under pulsed DBA

Enhanced ability to evaluate the feasibility of SPAD detection probability variations as a countermeasure

Capability to estimate the fraction of compromised bits during pulsed DBA

Abstract

We present a countermeasure against the detector blinding attack (DBA) utilizing statistical analysis of error and double-click events accumulated during a quantum key distribution session under randomized modulation of single-photon avalanche diode (SPAD) detection efficiencies via gate voltage manipulation. Building upon prior work demonstrating the ineffectiveness of this countermeasure against continuous-wave (CW) DBA, we extend the analysis to evaluate its performance against pulsed DBA. Our findings reveal an approximately 25 dB increase in the trigger pulse energies difference between high and low gate voltage applied under pulsed DBA conditions compared to CW DBA. This heightened difference enables a re-evaluation of the feasibility of utilizing SPAD detection probability variations as a countermeasure and makes it possible to estimate the fraction of bits compromised by an adversary during pulsed DBA.