论文标题
改善高损耗通道的连贯的单向量子键分布
Improved coherent one-way quantum key distribution for high-loss channels
论文作者
论文摘要
连贯的单向（牛）量子密钥分布（QKD）是一种高度实用的量子通信协议，目前已在现成的产品中部署。但是，尽管具有简单性和广泛使用，但Cow-QKD的安全性仍然是一个开放的问题。这在很大程度上是由于其基于信号阶段分布的独特安全功能，这使得使用标准安全性证明技术很难分析。在这里，为了克服这个问题，我们提出了一个简单的cow-qkd变体，并在无限键限制中证明了其安全性。所提出的修改仅涉及每个编码信号之后的额外真空尾信号和用于被动测量基础选择的平衡梁拆分。值得注意的是，我们协议的最终关键速率与Cow-QKD关键率的现有上限和相干状态BB84协议的安全密钥率相当。因此，我们的发现表明，在高损失光学网络中的cow-QKD系统的安全部署确实是可行的，并且适用于其硬件和软件的最低适应性。
The coherent one-way (COW) quantum key distribution (QKD) is a highly practical quantum communication protocol that is currently deployed in off-the-shelves products. However, despite its simplicity and widespread use, the security of COW-QKD is still an open problem. This is largely due to its unique security feature based on inter-signal phase distribution, which makes it very difficult to analyze using standard security proof techniques. Here, to overcome this problem, we present a simple variant of COW-QKD and prove its security in the infinite-key limit. The proposed modifications only involve an additional vacuum tail signal following every encoded signal and a balanced beam-splitter for passive measurement basis choice. Remarkably, the resulting key rate of our protocol is comparable with both the existing upper-bound on COW-QKD key rate and the secure key rate of the coherent-state BB84 protocol. Our findings therefore suggest that the secured deployment of COW-QKD systems in high loss optical networks is indeed feasible with minimal adaptations applied to its hardware and software.
