标题： 基于真实单光子纠缠态的二维交替量子行走的双重消息传递系统的量子密码协议 显示英文标题

标题： Quantum cryptographic protocols with dual messaging system via 2D alternate quantum walk of a genuine single-photon entangled state

摘要： 单光子纠缠态（或一般意义上的单粒子纠缠态（SPES））可以提供比其多光子（或多粒子）对应物更安全的量子信息编码和处理方式。 通过二维交替量子行走设置从初始可分离状态生成的SPES可以是三路纠缠态或者两路纠缠态。 本文表明，生成的真实三路和非局域两路SPES可以用作加密密钥，以同时安全地编码两个不同的消息。 我们详细描述了消息加密-解密步骤，并展示了基于三路和两路SPES的加密协议对窃听者攻击（如拦截和重发以及中间人攻击）的抗性。 我们还详细介绍了使用单光子实现这些协议的实验，其中三个自由度分别是轨道角动量、路径和偏振。 我们已经证明，这些协议对于量子通信任务具有无条件的安全性。 利用生成的SPES同时编码两个不同消息的能力展示了所提出的加密协议的多样性和效率。 这一能力可能显著提高量子通信系统的吞吐量。 显示英文摘要

摘要： A single-photon entangled state (or single-particle entangled state (SPES) in general) can offer a more secure way of encoding and processing quantum information than their multi-photon (or multi-particle) counterparts. The SPES generated via a 2D alternate quantum-walk setup from initially separable states can be either 3-way or 2-way entangled. This letter shows that the generated genuine three-way and nonlocal two-way SPES can be used as cryptographic keys to securely encode two distinct messages simultaneously. We detail the message encryption-decryption steps and show the resilience of the 3-way and 2-way SPES-based cryptographic protocols against eavesdropper attacks like intercept-and-resend and man-in-the-middle. We also detail the experimental realization of these protocols using a single photon, with the three degrees of freedom being OAM, path, and polarization. We have proved that the protocols have unconditional security for quantum communication tasks. The ability to simultaneously encode two distinct messages using the generated SPES showcases the versatility and efficiency of the proposed cryptographic protocol. This capability could significantly improve the throughput of quantum communication systems.