一步量子保密直接通信。

One-step quantum secure direct communication.

机构信息

College of Electronic and Optical Engineering & College of Microelectronics, Nanjing University of Posts and Telecommunications, Nanjing 210003, China; Institute of Quantum Information and Technology, Nanjing University of Posts and Telecommunications, Nanjing 210003, China.

School of Science, Nanjing University of Posts and Telecommunications, Nanjing 210003, China.

出版信息

Sci Bull (Beijing). 2022 Feb 26;67(4):367-374. doi: 10.1016/j.scib.2021.11.002. Epub 2021 Nov 4.

DOI:10.1016/j.scib.2021.11.002

PMID:36546088

Abstract

Quantum secure direct communication (QSDC) attracts much attention for it can transmit secret messages directly without sharing a key. In this article, we propose a one-step QSDC protocol, which only requires to distribute polarization-spatial-mode hyperentanglement for one round. In this QSDC protocol, the eavesdropper cannot obtain any message, so that this protocol is unconditionally secure in principle. This protocol is a two-way quantum communication and has high capacity for it can transmit two bits of secret messages with one pair of hyperentanglement. With entanglement fidelities of both polarization and spatial-mode degrees of freedom being 0.98, the maximal communication distance of this one-step QSDC can reach about 216 km. QSDC can also be used to generate the key. In this regard, the key generation rate is estimated about 2.5 times of that in the entanglement-based QKD with the communication distance of 150 km. With the help of future quantum repeaters, this QSDC protocol can provide unconditionally secure communication over arbitrarily long distance.

摘要

量子安全直接通信（QSDC）吸引了广泛的关注，因为它可以在不共享密钥的情况下直接传输秘密消息。在本文中，我们提出了一种单步 QSDC 协议，该协议只需要分发一轮偏振-空间模式超纠缠。在这个 QSDC 协议中，窃听者无法获得任何消息，因此该协议在原则上是无条件安全的。该协议是一种双向量子通信，具有较高的容量，因为它可以使用一对超纠缠传输两个比特的秘密消息。当偏振和空间模式自由度的纠缠保真度分别为 0.98 时，这种单步 QSDC 的最大通信距离可达约 216km。QSDC 也可用于生成密钥。在这方面，估计在 150km 通信距离的基于纠缠的 QKD 的密钥生成率约为其 2.5 倍。在未来量子中继器的帮助下，该 QSDC 协议可以在任意长的距离上提供无条件安全的通信。