{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T02:21:12Z","timestamp":1760149272358,"version":"build-2065373602"},"reference-count":40,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2023,7,20]],"date-time":"2023-07-20T00:00:00Z","timestamp":1689811200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Natural Science Foundation of China","award":["62001041","62201012","2022RC08","IPOC2022ZT09","2022"],"award-info":[{"award-number":["62001041","62201012","2022RC08","IPOC2022ZT09","2022"]}]},{"name":"Fundamental Research Funds of BUPT","award":["62001041","62201012","2022RC08","IPOC2022ZT09","2022"],"award-info":[{"award-number":["62001041","62201012","2022RC08","IPOC2022ZT09","2022"]}]},{"name":"Fund of State Key Laboratory of Information Photonics and Optical Communications","award":["62001041","62201012","2022RC08","IPOC2022ZT09","2022"],"award-info":[{"award-number":["62001041","62201012","2022RC08","IPOC2022ZT09","2022"]}]},{"name":"stability Program of Science and Technology on Communication Security Laboratory","award":["62001041","62201012","2022RC08","IPOC2022ZT09","2022"],"award-info":[{"award-number":["62001041","62201012","2022RC08","IPOC2022ZT09","2022"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Symmetry"],"abstract":"<jats:p>Continuous-variable quantum key distribution (CV\u2013QKD) is a system that provides secret keys for symmetric key systems. In the application of CV\u2013QKD, the practical security of the system is crucial. In this article, we investigate the practical security issues caused by non\u2013ideal Gaussian modulation, which is caused by fitting defects of the amplitude modulator\u2019s (AM) modulation curve. We provide the effect of fitting error on parameter estimation. We also give the relationship between the fitting order and the secret key rate. The simulation results indicate that the system is completely unable to communicate during first\u2013order fitting. During second\u2013order fitting, the system\u2019s performance decreases by more than half. During third\u2013order fitting, the system\u2019s performance will be consistent with the ideal. Therefore, to ensure the performance of the CV\u2013QKD system, the fitting order must be at least three or higher.<\/jats:p>","DOI":"10.3390\/sym15071452","type":"journal-article","created":{"date-parts":[[2023,7,21]],"date-time":"2023-07-21T01:52:35Z","timestamp":1689904355000},"page":"1452","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Security Analysis of Imperfect Gaussian Modulation Caused by Amplitude Modulator in Continuous\u2013Variable Quantum Key Distribution"],"prefix":"10.3390","volume":"15","author":[{"given":"Zhenghua","family":"Li","sequence":"first","affiliation":[{"name":"State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2132-0065","authenticated-orcid":false,"given":"Xiangyu","family":"Wang","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8343-8029","authenticated-orcid":false,"given":"Ziyang","family":"Chen","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Advanced Optical Communication Systems and Networks, Department of Electronics, and Center for Quantum Information Technology, Peking University, Beijing 100871, China"}]},{"given":"Bingjie","family":"Xu","sequence":"additional","affiliation":[{"name":"Science and Technology on Communication Security Laboratory, Institute of Southwestern Communication, Chengdu 610041, China"}]},{"given":"Song","family":"Yu","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876, China"}]}],"member":"1968","published-online":{"date-parts":[[2023,7,20]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1800011","DOI":"10.1002\/qute.201800011","article-title":"Continuous-variable quantum key distribution with Gaussian modulation\u2014the theory of practical implementations","volume":"1","author":"Laudenbach","year":"2018","journal-title":"Adv. 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