Evaluating the Eavesdropper Entropy via Bloch-Messiah Decomposition
Quantum Physics
2021-08-02 v1
Abstract
We explore the Bloch-Messiah decomposition of Gaussian unitary to analyze the Entangling Cloner Attack performed by an eavesdropper on a discrete modulated continuous variable QKD scenario. Such a decomposition allows to replace the nonlinear unitary resulting from eavesdropping and tracing out Bob's mode into an architecture of single-mode operations (squeezers, phase shifters and displacements) and a two-mode beam splitter. Based on such architecture we were able to get tighter upper bounds to the eavesdropper entropy for a discrete modulated CVQKD scheme. The new bounds are justified from the Gaussian extremality property valid for entangled-based equivalent protocols.
Cite
@article{arxiv.2107.14752,
title = {Evaluating the Eavesdropper Entropy via Bloch-Messiah Decomposition},
author = {Micael Andrade Dias and Francisco Marcos de Assis},
journal= {arXiv preprint arXiv:2107.14752},
year = {2021}
}
Comments
6 pages, 1 figure, Conference paper