2019/04/17 by Yi Zheng, Peng Huang, Anqi Huang +2
Computer Science · Mathematics · Physics and Astronomy · #Attenuation #Computer science #Computer security #Continuous variable #Distribution (mathematics) #Environmental science #Key (lock) #Mathematical analysis #Mathematics #Physics #Quantum #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum Mechanics and Applications #Quantum key distribution #Quantum mechanics #Statistics #Variable (mathematics) #physics.optics #quant-ph
paper · pdf · doi:10.1103/physreva.100.012313
published as Phys. Rev. A 100, 012313 (2019) · 9 pages, 8 figures
arxiv created 2019/04/17 · openalex publication_date 2019/07/09 · arxiv updated 2019/07/17 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
In a practical continuous-variable quantum key distribution (CVQKD) system, the optical attenuator can adjust the Gaussian-modulated coherent states and the local oscillator signal to an optimal value for guaranteeing the security of the system and optimizing the performance of the system. However, the performance of the optical attenuator may deteriorate due to the intentional and unintentional damage of the device. In this paper, we investigate the practical security of a CVQKD system with reduced optical attenuation. We find that the secret key rate of the system may be overestimated based on the investigation of parameter estimation under the effects of reduced optical attenuation. This opens a security loophole for Eve to successfully perform an intercept-resend attack in a practical CVQKD system. To close this loophole, we add an optical fuse at Alice's output port and design a scheme to monitor the level of optical attenuation in real time, which can make the secret key rate of the system evaluated precisely. The analysis shows that these countermeasures can effectively resist this potential attack.