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arXiv · 2303.12355

Security boundaries of an optical power limiter for protecting quantum key distribution systems

Qingquan Peng·Binwu Gao·Konstantin Zaitsev·Dongyang Wang·Jiangfang Ding·Yingwen Liu·Qin Liao·Ying Guo·Anqi Huang·Junjie Wu
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Abstract

Unauthorized light injection has always been a vital threat to the practical security of a quantum key distribution (QKD) system. An optical power limiter (OPL) based on the thermo-optical defocusing effect has been proposed and implemented, limiting the injected hacking light. As a hardware countermeasure, the performance of the OPL under various light-injection attacks shall be tested to clarify the security boundary before being widely deployed. To investigate the OPL's security boundary in quantum cryptography, we comprehensively test and analyse the behavior of OPL under continuous-wave (c.w.) light-injection attacks and pulse illumination attacks with pulses' repetition rate at $0.5$-$\hertz$, $40$-$\mega\hertz$, and $1$-$\giga\hertz$. The testing results illuminate the security boundary of the OPL, which allows one to properly employ the OPL in the use cases. The methodology of testing and analysis proposed here is applicable to other power-limitation components in a QKD system.

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Qingquan Peng, Binwu Gao, Konstantin Zaitsev, Dongyang Wang, Jiangfang Ding, Yingwen Liu, Qin Liao, Ying Guo, Anqi Huang, Junjie Wu. 2023-03-22. Security boundaries of an optical power limiter for protecting quantum key distribution systems. https://doi.org/10.1103/physrevapplied.21.014026

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