Feasibility of quantum-secure communication in real-world networks

In a world that heavily relies on the secrecy of digital data, the ongoing trend in the development of quantum computers is raising new concerns about the vulnerabilities of the ubiquitous public-key cryptography, which forms the foundation of common banking systems and blockchain technology. While these cryptographic schemes rely on the computational complexity of specific mathematical problems, Quantum Key Distribution (QKD) is claimed to provide unconditionally secure communication “by the laws of physics”. On the other side, QKD's practical implementation is hindered by the severe decay of the information rates with the distance, which is intrinsic to the same quantum principles it relies on. The question driving this work is whether a real-world network, such as the one constituted by the Internet fiber infrastructure, might mitigate the rate-distance tradeoff enough to sustain a quantum-encrypted communication between trusted nodes.