Communication security has to evolve to a higher plane in the face of the threat from the massive computing power of the emerging quantum computers. Quantum secure direct communication (QSDC) constitutes a promising branch of quantum communication, which is provably secure and overcomes the threat of quantum computing, whilst conveying secret messages directly via the quantum channel. In this survey, we highlight the motivation and the status of QSDC research with special emphasis on its theoretical basis and experimental verification. We will detail the associated point-to-point communication protocols and show how information is protected and transmitted. Finally, we discuss the open challenges as well as the future trends of QSDC networks, emphasizing again that QSDC is not a pure quantum key distribution (QKD) protocol, but a fully-fledged secure communication scheme.

中文翻译：

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量子安全直连通信的演进：迈向Qinternet之路


面对新兴量子计算机海量算力的威胁，通信安全必须向更高层面发展。量子安全直接通信（QSDC）构成了量子通信的一个有前途的分支，它是可证明安全的，克服了量子计算的威胁，同时通过量子通道直接传送秘密消息。在本次调查中，我们强调了QSDC研究的动机和现状，特别强调其理论基础和实验验证。我们将详细介绍相关的点对点通信协议，并展示如何保护和传输信息。最后，我们讨论了 QSDC 网络的开放挑战以及未来趋势，再次强调 QSDC 不是纯粹的量子密钥分发（QKD）协议，而是一种成熟的安全通信方案。