"Yet for high-speed transmissions under real-world conditions, the record is just 60 miles. Farther transmissions require a series of “trusted nodes,” relays th

"Yet for high-speed transmissions under real-world conditions, the record is just 60 miles. Farther transmissions require a series of “trusted nodes,” relays that are themselves vulnerable to hackers or physical tapping. China uses armed guards to secure the nodes in its 1,240-mile QKD network" Armed guards at the relays.. I wonder what they are transmitting on that cable. In any case it seems they take the thread of fiber tapping very seriously. I bet the US government have similar experiments only they don't talk about it.