Robust Shot Noise Measurement for Continuous Variable Quantum Key Distribution

TL;DR

This paper presents a practical real-time shot noise measurement method for CVQKD systems, enhancing security against hacking attacks that manipulate noise estimates, thereby improving the robustness of quantum key distribution.

Contribution

The paper introduces a new method for real-time shot noise measurement in CVQKD that can effectively counteract saturation and wavelength hacking attacks.

Findings

Method successfully defeats saturation attack

Method effectively counters wavelength attack

Provides experimental validation of security enhancement

Abstract

We study a practical method to measure the shot noise in real time in Continuous Variable Quantum Key Distribution (CVQKD) systems. The amount of secret key that can be extracted from the raw statistics depends strongly on this quantity since it affects in particular the computation of the excess noise (i.e. noise in excess of the shot noise) added by an eavesdropper on the quantum channel. Some powerful quantum hacking attacks relying on faking the estimated value of the shot noise to hide an intercept and resend strategy were proposed. Here, we provide experimental evidence that our method can defeat the saturation attack and the wavelength attack.