Technology
Quantum Key Distribution over Metropolitan Optical Networks
Quick fact
In QKD, any attempt to eavesdrop on the key transmission necessarily disturbs the quantum states, alerting the legitimate users — this is guaranteed by quantum mechanics, not by computational assumptions.
Why this is interesting
Imagine encrypting a message with a key that is mathematically impossible to copy — because the laws of physics prevent it. How can we send such unbreakable keys across a city's fiber-optic network?