Trusted source noise model of discrete-modulated continuous-variable quantum key distribution

TL;DR

This paper introduces a trusted source noise model for discrete-modulated continuous-variable quantum key distribution, improving security analysis and performance by accounting for intrinsic source noise that cannot be controlled by eavesdroppers.

Contribution

It develops a tailored trusted source noise model for the protocol, enhancing security analysis and practical deployment of quantum key distribution systems.

Findings

Mitigates negative impact of source noise on system performance

Maintains security while reducing influence of source and detector noise

Compatible with trusted detector noise models for better practical implementation

Abstract

Discrete-modulated continuous-variable quantum key distribution offers a pragmatic solution, greatly simplifying experimental procedures while retaining robust integration with classical optical communication. Theoretical analyses have progressively validated the comprehensive security of this protocol, paving the way for practical experimentation. However, imperfect source in practical implementations introduce noise. The traditional approach is to assume that eavesdroppers can control all of the source noise, which overestimates the ability of eavesdroppers and underestimates secret key rate. In fact, some parts of source noise are intrinsic and cannot be manipulated by eavesdropper, so they can be seen as trusted noise. We tailor a trusted model specifically for the discrete-modulated protocol and upgrade the security analysis accordingly. Simulation results demonstrate that this approach successfully mitigates negative impact of imperfect source on system performance while maintaining security of the protocol. Furthermore, our method can be used in conjunction with trusted detector noise model, effectively reducing the influence of both source and detector noise in experimental setup. This is a meaningful contribution to the practical deployment of discrete-modulated continuous-variable quantum key distribution systems.