Abstract

Quantum key distribution (QKD) is a quantum technology which creates a common secret key between two distant users without any technological and computational assumptions about the eavesdropper. Nevertheless, not all the QKD protocols have tight upper and lower security bounds, thus the study of eavesdropping strategies and countermeasures is important. Using large number of symmetric coherent states is one of possible technologies in quantum key distribution against unambiguous state discrimination (USD) attack. Here we propose an attack based on heterodyne measurement, which is relatively simple for practical implementation and which becomes more powerful than USD attack when the number of states in the protocol is large enough. We study the performance of this attack for various symmetric coherent states QKD protocol parameters and for various distances between the legitimate users.

中文翻译：

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基于外差测量的对称相干态量子密码窃听策略

摘要

量子密钥分发 (QKD) 是一种量子技术，它在两个远程用户之间创建公共密钥，而无需对窃听者进行任何技术和计算假设。然而，并非所有 QKD 协议都有严格的安全上下界，因此对窃听策略和对策的研究很重要。使用大量对称相干态是量子密钥分发中对抗明确状态鉴别（USD）攻击的可能技术之一。在这里我们提出了一种基于外差测量的攻击，它在实际实现中相对简单，并且当协议中的状态数量足够大时，它比美元攻击更强大。