Hacking high-speed quantum-key-distribution systems by tailoring the blinding pulse
Phys. Rev. Applied 25, 024053 – Published 18 February, 2026
DOI: https://doi.org/10.1103/nqz3-z1zb
Abstract
Currently, quantum-key-distribution (QKD) systems are evolving toward high-speed implementations to meet the demands of large-scale data encryption. High-performance, high-speed gated single-photon detectors (SPDs) are essential for enabling such systems. However, the practical security of these detectors remains a critical concern. Recently, an attack targeting high-speed sine-gated SPDs was reported, in which the detector was blinded by deceiving the width discrimination mechanism. Inspired by this work, we further optimize the attack strategy by customizing the blinding pulse and modifying the temporal offset between the blinding pulse and the gate signal, thereby achieving a more effective attack. Experimental and simulation results show that in short-distance communication scenarios, the additional quantum bit error rate (QBER) introduced by our proposed attack strategy is less than 0.5%. Of note, we propose and evaluate three practical countermeasures to defend against such attacks, which include auxiliary conventional discrimination monitoring, avalanche current monitoring, and temporal distribution analysis of detection events. These defense strategies enhance the robustness of high-speed SPDs and contribute to the development of more secure and reliable QKD systems.
