We use a recent numerical security proof approach to calculate tight secure key rates in the presence of collective attacks for a continuous-variable (CV) eight-state phase-shift keying (8PSK) protocol with heterodyne detection in the asymptotic limit. The results are compared to achievable secure key rates of a QPSK protocol obtained with the same security proof technique. Furthermore, we investigate the influence of radial postselection on the secure key rate and examine a recently suggested strategy to reduce the computational requirements on the error-correction phase for four-state phase-shift-keying protocols. Based on our investigations, we suggest different strategies to reduce the raw key of 8PSK protocols significantly, only on the cost of a slightly lower secure key rate. This can be used to lower the computational effort of the error-correction phase, a known bottleneck in many practical implementations, considerably.
Cite
@article{arxiv.2107.06110,
title = {Tight Secure Key Rates for CV-QKD with 8PSK Modulation},
author = {Florian Kanitschar and Christoph Pacher},
journal= {arXiv preprint arXiv:2107.06110},
year = {2022}
}
Comments
12 pages, 8 figures, 2 tables; V2: typos corrected. arXiv admin note: text overlap with arXiv:2104.09454