Spectral side channels in quantum key distribution under laser damage

Fuente: arXiv
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Main Authors: Gao, Binwu, Liu, Junxuan, Borisova, Ekaterina, Tan, Hao, Zhong, Mingyang, Chen, Zihao, Peng, Qingquan, Shi, Weixu, Ponosova, Anastasiya, Makarov, Vadim, Huang, Anqi
Format: Preprint
Published: 2025
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author Gao, Binwu
Liu, Junxuan
Borisova, Ekaterina
Tan, Hao
Zhong, Mingyang
Chen, Zihao
Peng, Qingquan
Shi, Weixu
Ponosova, Anastasiya
Makarov, Vadim
Huang, Anqi
author_facet Gao, Binwu
Liu, Junxuan
Borisova, Ekaterina
Tan, Hao
Zhong, Mingyang
Chen, Zihao
Peng, Qingquan
Shi, Weixu
Ponosova, Anastasiya
Makarov, Vadim
Huang, Anqi
contents In the transmitter of a quantum key distribution (QKD) system, a dense wavelength-division multiplexer (DWDM) is typically used to combine quantum and synchronization signals and is directly connected to the quantum channel. As a result, it becomes the first optical component exposed to laser-injection attacks. Therefore, understanding the behavior of DWDMs under such attacks is essential for assessing the practical security of QKD systems. In this work, we systematically investigate the characteristics of DWDMs under high-power laser illumination. Our experimental results show that certain DWDM samples exhibit pronounced changes in their spectral features once the injected laser power surpasses a specific threshold. Taking the Trojan-horse attack as an illustrative example, we further perform a theoretical analysis of the resulting spectral side channel and show that it can reduce the maximum secure transmission distance to below 66.9% of its original value. By combining experimental observations with theoretical modeling, this study advances the understanding of the influence of DWDMs on the practical security of QKD systems.
format Preprint
id arxiv_https___arxiv_org_abs_2512_11701
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Spectral side channels in quantum key distribution under laser damage
Gao, Binwu
Liu, Junxuan
Borisova, Ekaterina
Tan, Hao
Zhong, Mingyang
Chen, Zihao
Peng, Qingquan
Shi, Weixu
Ponosova, Anastasiya
Makarov, Vadim
Huang, Anqi
Quantum Physics
In the transmitter of a quantum key distribution (QKD) system, a dense wavelength-division multiplexer (DWDM) is typically used to combine quantum and synchronization signals and is directly connected to the quantum channel. As a result, it becomes the first optical component exposed to laser-injection attacks. Therefore, understanding the behavior of DWDMs under such attacks is essential for assessing the practical security of QKD systems. In this work, we systematically investigate the characteristics of DWDMs under high-power laser illumination. Our experimental results show that certain DWDM samples exhibit pronounced changes in their spectral features once the injected laser power surpasses a specific threshold. Taking the Trojan-horse attack as an illustrative example, we further perform a theoretical analysis of the resulting spectral side channel and show that it can reduce the maximum secure transmission distance to below 66.9% of its original value. By combining experimental observations with theoretical modeling, this study advances the understanding of the influence of DWDMs on the practical security of QKD systems.
title Spectral side channels in quantum key distribution under laser damage
topic Quantum Physics
url https://arxiv.org/abs/2512.11701