A denial-of-service attack on fiber-based continuous-variable quantum key distribution

In a fiber-based continuous-variable quantum key distribution (CVQKD) system, to perform the channel estimation, the channel transmittance is usually assumed to be a constant. Subsequently, when the channel parameters are intentionally manipulated, the employed parameter estimation method will lead to deviations of channel parameters and ultimately impacting the evaluation of the secret key rate. In this paper, we propose a denial-of-service attack strategy based on Eve's manipulation of the channel parameters. In particular, we analyze in detail the impact of this attack when the channel transmittance is attacked and obeys two-point distribution and uniform distribution. The result shows that in both cases, Eve's slight manipulation on the quantum channel will lead to large underestimation of the secure transmission distance by using the previous parameter estimation, which will lead to intentional terminations of the communication. To prevent this attack, a simple data post-selection should be added before parameter estimation.