Xu Shengjie, Li Yin, Wang Yijun, Mao Yun, Wu Xiaodong, Guo Ying
School of Automation, Central South University, Changsha 410083, China.
School of Economics and Mangement, Beihua University, Jilin 132013, China.
Entropy (Basel). 2021 Dec 19;23(12):1698. doi: 10.3390/e23121698.
We perform security analysis of a passive continuous-variable quantum key distribution (CV-QKD) protocol by considering the finite-size effect. In the passive CV-QKD scheme, Alice utilizes thermal sources to passively make preparation of quantum state without Gaussian modulations. With this technique, the quantum states can be prepared precisely to match the high transmission rate. Here, both asymptotic regime and finite-size regime are considered to make a comparison. In the finite-size scenario, we illustrate the passive CV-QKD protocol against collective attacks. Simulation results show that the performance of passive CV-QKD protocol in the finite-size case is more pessimistic than that achieved in the asymptotic case, which indicates that the finite-size effect has a great influence on the performance of the single-mode passive CV-QKD protocol. However, we can still obtain a reasonable performance in the finite-size regime by enhancing the average photon number of the thermal state.
我们通过考虑有限尺寸效应来对一种被动连续变量量子密钥分发（CV-QKD）协议进行安全性分析。在被动CV-QKD方案中，爱丽丝利用热光源被动地制备量子态，无需高斯调制。通过这种技术，可以精确制备量子态以匹配高传输速率。在此，同时考虑渐近情形和有限尺寸情形以进行比较。在有限尺寸场景中，我们针对集体攻击阐述被动CV-QKD协议。仿真结果表明，有限尺寸情况下被动CV-QKD协议的性能比渐近情况下更为悲观，这表明有限尺寸效应会对单模被动CV-QKD协议的性能产生很大影响。然而，通过提高热态的平均光子数，我们在有限尺寸情形下仍可获得合理的性能。
