离散调制连续变量量子密钥分发在无限维MEAT下的无条件安全性
Unconditional Security of Discrete-Modulated CV-QKD from Infinite-Dimensional MEAT
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中文总结 AI 辅助
本文首次为离散调制连续变量QKD建立了针对相干攻击的完整可组合有限尺寸安全性证明，引入无限维边际约束熵累积定理和降维技术，在超70公里距离上获得正密钥率，弥合了长期理论空白。
中文摘要 AI 辅助
离散调制（DM）连续变量（CV）量子密钥分发（QKD）是量子密码学中一种实验上颇具吸引力的方法，它利用最先进的电信基础设施，在大都市尺度距离上提供高密钥率。然而，这一实验前景与严格安全性之间一直存在根本性差距：二十多年来，DM CV-QKD一直缺乏针对相干攻击的完整可组合有限尺寸安全性证明。现有工作要么将对手限制为集体攻击，要么施加额外的有限维假设，要么仅适用于特定调制格式，要么无法恢复已知的渐近密钥率。在此，我们通过建立针对相干攻击的DM CV-QKD协议的首个完整可组合有限尺寸安全性证明，解决了这一长期存在的问题，该证明包含了不完美探测器以及固定长度和可变长度两种协议变体。我们的证明引入了两个具有更广泛意义的核心结果：一个无限维边际约束熵累积定理（iMEAT）和一个严格的降维技术，使无限维安全性界在数值上可处理。由此得到的密钥率恢复了已知的渐近密钥率，并优于基于集体攻击的既有有限尺寸界，同时在实验相关的块大小和参数下，在超过70公里的距离上产生正密钥率。因此，我们的工作弥合了长期存在的差距，为实验上颇具吸引力的一类CV-QKD协议奠定了严格的可组合安全性基础，并为其实际部署提供了途径。
英文摘要
Discrete-Modulated (DM) Continuous-Variable (CV) Quantum Key Distribution (QKD) is an experimentally attractive approach to quantum cryptography, offering high key rates over metropolitan-scale distances while relying on state-of-the-art telecom infrastructure. However, a fundamental gap has remained between this experimental promise and rigorous security: for more than two decades, DM CV-QKD has lacked a complete composable finite-size security proof against coherent attacks. Existing works either restrict the adversary to collective attacks, impose additional finite-dimensional assumptions, apply only to specific modulation formats, or fail to recover the known asymptotic rates. Here, we resolve this longstanding problem by establishing the first complete composable finite-size security proof for DM CV-QKD protocols against coherent attacks, incorporating imperfect detectors and both fixed- and variable-length protocol variants. Our proof introduces two central results of broader interest: an infinite-dimensional marginal-constrained entropy accumulation theorem (iMEAT) and a rigorous dimension-reduction technique that makes the infinite-dimensional security bounds numerically tractable. The resulting key rates recover the known asymptotic rates and outperform established finite-size bounds based on collective attacks, while yielding positive key rates beyond $70$km for experimentally relevant block sizes and parameters. Thus, our work closes a longstanding gap and places an experimentally attractive class of CV-QKD protocols on a rigorous composable security footing and provides a pathway towards their practical deployment.
发表机构
- University of Waterloo（滑铁卢大学）
- National University of Singapore（新加坡国立大学）
- Technische Universität Wien（维也纳工业大学）
- AIT Austrian Institute of Technology（奥地利技术研究院）
机构由 AI 辅助整理，请以论文原文为准。
