Quantum secure direct communication (QSDC) can realize the direct and secure transmission of information instead of sharing secure keys between two parties. Similar to quantum key distribution (QKD), in practical applications, QSDC may suffer from attacks from imperfect detector. Measurement-device–independent QSDC (MDI-QSDC) can remove all attacks at detector's side and close all loopholes in the detection system. However, existing MDI-QSDC protocols have relatively low capacity. In this paper, we propose a high-capacity MDI-QSDC protocol of multiple degrees of freedom of a single photon. Compared with original MDI-QSDC protocols, our protocol has larger channel capacity which can use a single photon to transmit multi-bit of secure information. This protocol may have potential application in future quantum secure communication.

中文翻译：

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与测量设备无关的单个光子多个自由度的量子安全直接通信

量子安全直接通信（QSDC）可以实现信息的直接安全传输，而无需在两方之间共享安全密钥。与量子密钥分发（QKD）类似，在实际应用中，QSDC可能会受到不完善检测器的攻击。独立于测量设备的QSDC（MDI-QSDC）可以消除检测器侧的所有攻击并掩盖检测系统中的所有漏洞。但是，现有的MDI-QSDC协议具有相对较低的容量。在本文中，我们提出了单个光子具有多个自由度的大容量MDI-QSDC协议。与原始MDI-QSDC协议相比，我们的协议具有更大的信道容量，可以使用单个光子传输多位安全信息。该协议在未来的量子安全通信中可能具有潜在的应用。