Practical security of twin-field quantum key distribution with optical phase-locked loop under wavelength-switching attack

Fuente: arXiv
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Main Authors: Peng, Qingquan, Chen, Jiu-Peng, Xing, Tianyi, Wang, Dongyang, Wang, Yizhi, Liu, Yang, Huang, Anqi
Format: Preprint
Published: 2024
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_version_ 1866913650553389056
author Peng, Qingquan
Chen, Jiu-Peng
Xing, Tianyi
Wang, Dongyang
Wang, Yizhi
Liu, Yang
Huang, Anqi
author_facet Peng, Qingquan
Chen, Jiu-Peng
Xing, Tianyi
Wang, Dongyang
Wang, Yizhi
Liu, Yang
Huang, Anqi
contents The twin-field class quantum key distribution (TF-class QKD) has experimentally demonstrated the ability to surpass the fundamental rate-distance limit without requiring a quantum repeater, as a revolutional milestone. In TF-class QKD implementation, an optical phase-locked loop (OPLL) structure is commonly employed to generate a reference light with correlated phase, ensuring coherence of optical fields between Alice and Bob. In this configuration, the reference light, typically located in the untrusted station Charlie, solely provides wavelength reference for OPLL and does not participate in quantum-state encoding. However, the reference light may open a door for Eve to enter the source stations that are supposed to be well protected. Here, by identifying vulnerabilities of an acousto-optic modulator (AOM) in the OPLL scheme, we propose and demonstrate a wavelength-switching attack on a TF-class QKD system. This attack involves Eve deliberately manipulating the wavelength of the reference light to increase mean photon number of prepared quantum states, while maintaining stable interference between Alice and Bob as required by TF-class QKD protocols. The maximum observed increase in mean photon number is 8.7%, which has been theoretically proven to compromise the security of a TF-class QKD system. Moreover, we have shown that with well calibration of the modulators, the attack can be eliminated. Through this study, we highlight the importance of system calibration in the practical security in TF-class QKD implementation.
format Preprint
id arxiv_https___arxiv_org_abs_2408_09318
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Practical security of twin-field quantum key distribution with optical phase-locked loop under wavelength-switching attack
Peng, Qingquan
Chen, Jiu-Peng
Xing, Tianyi
Wang, Dongyang
Wang, Yizhi
Liu, Yang
Huang, Anqi
Quantum Physics
Optics
81P94
The twin-field class quantum key distribution (TF-class QKD) has experimentally demonstrated the ability to surpass the fundamental rate-distance limit without requiring a quantum repeater, as a revolutional milestone. In TF-class QKD implementation, an optical phase-locked loop (OPLL) structure is commonly employed to generate a reference light with correlated phase, ensuring coherence of optical fields between Alice and Bob. In this configuration, the reference light, typically located in the untrusted station Charlie, solely provides wavelength reference for OPLL and does not participate in quantum-state encoding. However, the reference light may open a door for Eve to enter the source stations that are supposed to be well protected. Here, by identifying vulnerabilities of an acousto-optic modulator (AOM) in the OPLL scheme, we propose and demonstrate a wavelength-switching attack on a TF-class QKD system. This attack involves Eve deliberately manipulating the wavelength of the reference light to increase mean photon number of prepared quantum states, while maintaining stable interference between Alice and Bob as required by TF-class QKD protocols. The maximum observed increase in mean photon number is 8.7%, which has been theoretically proven to compromise the security of a TF-class QKD system. Moreover, we have shown that with well calibration of the modulators, the attack can be eliminated. Through this study, we highlight the importance of system calibration in the practical security in TF-class QKD implementation.
title Practical security of twin-field quantum key distribution with optical phase-locked loop under wavelength-switching attack
topic Quantum Physics
Optics
81P94
url https://arxiv.org/abs/2408.09318