Quantum cryptography systems may not be as secure as they are believed to be. According to V3.co.uk, researchers at the Norwegian University of Science and Technology were able to hack quantum network traffic using a 1 milliwatt laser.
As the article notes:
Quantum signals are touted as perfectly secure, since the act of observing the signal changes it and alerts the receiver to the interception.
However, researchers used the laser to trick the receiver into believing the message had not been tampered with. The attack worked on systems from Swiss firm ID Quantique and a MagiQ Technologies system built in the United States.