Until quantum repeaters become mature, quantum networks remain restricted either to limited areas of directly connected nodes or to nodes connected to a common node. We circumvent this limitation by conceiving quantum networks using secure classical repeaters combined with the quantum secure direct communication (QSDC) principle, which is a compelling form of quantum communication that directly transmits information over a quantum channel. The final component of this promising solution is our classical quantum-resistant algorithm. Explicitly, in these networks, the ciphertext gleaned from a quantum-resistant algorithm is transmitted using QSDC along the nodes, where it is read out by one node and then transmitted to the next node. At the repeaters, the information is protected by our quantum-resistant algorithm, which is secure even in the face of a quantum computer. Hence, our solution offers secure end-to-end communication across the entire network, since it is capable of both eavesdropping detection and prevention in the emerging quantum Internet. It is compatible with operational networks, and will enjoy the compelling services of the popular Internet, including authentication. Hence, it smoothens the transition from the classical Internet to the quantum Internet (Qinternet) by following a gradual evolutionary upgrade. It will act as an alternative network in quantum computing networks in the future. We have presented the first experimental demonstration of a secure classical-repeater-based hybrid quantum network constructed by a serial concatenation of an optical fiber and free-space communication link. In conclusion, secure repeater networks may indeed be constructed using existing technology and continue to support a seamless evolutionary pathway to the future Qinternet of quantum computers.

中文翻译：

---

依赖安全经典中继器的量子互联网的进化路径

在量子中继器成熟之前，量子网络仍然受限于直接连接节点的有限区域或连接到公共节点的节点。我们通过使用安全经典中继器与量子安全直接通信 (QSDC) 原理相结合的量子网络来规避这一限制，这是一种引人注目的量子通信形式，可通过量子通道直接传输信息。这个有前途的解决方案的最后一个组成部分是我们经典的抗量子算法。明确地说，在这些网络中，从抗量子算法收集的密文使用 QSDC 沿节点传输，由一个节点读出，然后传输到下一个节点。在中继器，信息受到我们的抗量子算法的保护，即使面对量子计算机也是安全的。因此，我们的解决方案提供了跨整个网络的安全端到端通信，因为它能够在新兴的量子互联网中进行窃听检测和预防。它与运营网络兼容，并将享受流行互联网的引人注目的服务，包括身份验证。因此，它通过逐步进化升级，平滑了从经典互联网到量子互联网（Qinternet）的过渡。它将作为未来量子计算网络中的替代网络。我们已经展示了由光纤和自由空间通信链路的串行连接构建的基于经典中继器的安全混合量子网络的首次实验演示。综上所述，