I Don't Believe in Imaginary Property writes "Professor Johannes Skaar's Quantum Hacking group at NTNU have found a new way to break quantum encryption. Even though quantum encryption is theoretically perfect, real hardware isn't, and they exploit these flaws. Their technique relies on a particular way of blinding the single photon detectors so that they're able to perform an intercept-resend attack and get a copy of the secret key without giving away the fact that someone is listening. This attack is not merely theoretical, either. They have built an eavesdropping device and successfully attacked their own quantum encryption hardware. More details can be found in their conference presentation."