Security of quantum key distribution with intensity correlations
Abstract
The decoy-state method in quantum key distribution (QKD) is a popular technique to approximately achieve the performance of ideal single-photon sources by means of simpler and practical laser sources. In high-speed decoy-state QKD systems, however, intensity correlations between succeeding pulses leak information about the users' intensity settings, thus invalidating a key assumption of this approach. Here, we solve this pressing problem by developing a general technique to incorporate arbitrary intensity correlations to the security analysis of decoy-state QKD. This technique only requires to experimentally quantify two main parameters: the correlation range and the maximum relative deviation between the selected and the actually emitted intensities. As a side contribution, we provide a non-standard derivation of the asymptotic secret key rate formula from the non-asymptotic one, in so revealing a necessary condition for the significance of the former.
Cite
@article{arxiv.2105.11165,
title = {Security of quantum key distribution with intensity correlations},
author = {Víctor Zapatero and Álvaro Navarrete and Kiyoshi Tamaki and Marcos Curty},
journal= {arXiv preprint arXiv:2105.11165},
year = {2025}
}
Comments
21 pages, 4 figures