Hackers break Quantum Encryption using MiTM

From PopSci:

Quantum Hackers Use Lasers to Crack Powerful Encryption Without Leaving a Trace

Quantum cryptography is one of the most secure known means of transmitting data, due to the fact that even if a third party does intercept a quantum signal, that interference changes the encryption key, making the tampering apparent to parties at both ends. But a handful of quantum hackers at Norwegian University of Science and Technology in Trondheim recently performed successful hacks of two commercial quantum cryptographic systems -- and they did so without leaving a trace.

Quantum encryption is based on the notion that you cannot take measurements of a quantum system without in some way disturbing it. A sender uses standard values of zeros and ones. That key is encoded into a beam of light using two different quantum states of photons. The receiver has a detector that measures the quantum states of the incoming photons. Anyone who messes with the signal in between will change it in some way, making it apparent to the sender and receiver that someone tampered with the signal.

http://www.popsci.com/technology/article/2010-08/quantum-hackers-use-lasers-crack-quantum-encryption-scheme-leaving-no-trace