Wang Yuang, Zou Shanhua, Mao Yun, Guo Ying
School of Automation, Central South University, Changsha 410083, China.
School of Internet of Things Engineering, Wuxi Taihu University, Wuxi 214064, China.
Entropy (Basel). 2020 May 19;22(5):571. doi: 10.3390/e22050571.
Underwater quantumkey distribution (QKD) is tough but important formodern underwater communications in an insecure environment. It can guarantee secure underwater communication between submarines and enhance safety for critical network nodes. To enhance the performance of continuous-variable quantumkey distribution (CVQKD) underwater in terms ofmaximal transmission distance and secret key rate as well, we adopt measurement-device-independent (MDI) quantum key distribution with the zero-photon catalysis (ZPC) performed at the emitter of one side, which is the ZPC-based MDI-CVQKD. Numerical simulation shows that the ZPC-involved scheme, which is a Gaussian operation in essence, works better than the single photon subtraction (SPS)-involved scheme in the extreme asymmetric case. We find that the transmission of the ZPC-involved scheme is longer than that of the SPS-involved scheme. In addition, we consider the effects of temperature, salinity and solar elevation angle on the system performance in pure seawater. The maximal transmission distance decreases with the increase of temperature and the decrease of sunlight elevation angle, while it changes little over a broad range of salinity.
水下量子密钥分发（QKD）对于不安全环境下的现代水下通信而言困难但重要。它能够保证潜艇之间安全的水下通信，并增强关键网络节点的安全性。为了在最大传输距离和密钥率方面提升连续变量量子密钥分发（CVQKD）在水下的性能，我们采用了测量设备无关（MDI）量子密钥分发，其中零光子催化（ZPC）在一侧的发射端执行，即基于ZPC的MDI-CVQKD。数值模拟表明，本质上是高斯操作的涉及ZPC的方案在极端不对称情况下比涉及单光子减法（SPS）的方案表现更好。我们发现涉及ZPC的方案的传输距离比涉及SPS的方案更长。此外，我们考虑了温度、盐度和太阳仰角对纯海水中系统性能的影响。最大传输距离随着温度的升高和太阳仰角的降低而减小，而在较宽的盐度范围内变化不大。
