Two groups have demonstrated device-independent quantum key distribution, which represents a major step towards secure quantum communication. Martijn Boerkamp explains
The quantum internet connects quantum-information-processing nodes (e.g., quantum computers) through quantum communication channels (e.g., optical fibers) to send, compute, and receive information encoded in quantum states. It has features the current Internet cannot provide such as unhackable communications and distributed quantum computing. In this article, quantum circuits are presented to simulate core quantum internet mechanisms, including quantum entanglement, quantum teleportation, entanglement swapping used in quantum repeaters, and quantum key distribution, to facilitate the learning of the core mechanisms. By observing the simulation results of the quantum circuits, readers can readily comprehend how the quantum internet achieves unhackable information transmission with unconditional security and how it enables large-scale distributed quantum computing and quantum cloud computing by coupling several quantum computers located worldwide.