Bian Yiming, Huang Luyu, Zhang Yichen
State Key Laboratory of Information Photonics and Optical Communications, School of Electronic Engineering, Beijing University of Posts and Telecommunications, Beijing 100876, China.
Entropy (Basel). 2021 Feb 27;23(3):294. doi: 10.3390/e23030294.
We propose a unidimensional two-way continuous-variable quantum key distribution protocol with coherent states, where the sender modulates a single quadrature of the coherent states rather than both quadratures to simplify the structure of a two-way system. Security analysis is performed with a general attack strategy, known as two-mode attack, which helps to reduce limitations in the analysis. The performance of the protocol under all accessible two-mode attacks at fixed distance is illustrated. Further, two typical two-mode attack strategies are obtained from it, which are one-mode attack strategy and optimal two-mode attack strategy. Between them, the one-mode attack is the simplest form of the two-mode attack, while the optimal two-mode attack is the most complicated one. Simulations show that though the system is simplified, the performance of the two-way protocol with unidimensional modulation is still comparable to that of the counterpart with Gaussian modulation even against the optimal two-mode attack when Eve's ability is maximized. Thus, the proposed protocol simplifies the two-way system while guaranteeing its performance to a certain extent. Especially in a practical system with short transmission distance and high excess noise, the protocol has a good application prospect.
我们提出了一种基于相干态的一维双向连续变量量子密钥分发协议，其中发送方调制相干态的单个正交分量而非两个正交分量，以简化双向系统的结构。采用一种称为双模攻击的通用攻击策略进行安全性分析，这有助于减少分析中的局限性。阐述了该协议在固定距离下所有可及双模攻击下的性能。此外，从中得到了两种典型的双模攻击策略，即单模攻击策略和最优双模攻击策略。其中，单模攻击是双模攻击的最简单形式，而最优双模攻击是最复杂的一种。仿真表明，尽管系统得到了简化，但即使在伊芙能力最大化且面对最优双模攻击的情况下，一维调制的双向协议性能仍与高斯调制的对应协议相当。因此，所提出的协议在一定程度上简化了双向系统，同时保证了其性能。特别是在传输距离短且过量噪声高的实际系统中，该协议具有良好的应用前景。
