A few years ago researchers found a way to eavesdrop on a commercial theoretically-secure quantum key distribution system. The trick was to replace the polarize

A few years ago researchers found a way to eavesdrop on a commercial theoretically-secure quantum key distribution system. The trick was to replace the polarized light pulses with bright pulses that overwhelmed the sensors, sidestepping the whole quantum business. The point is that even if a system is theoretically unbreakable, it's only as secure as the implementation, which may have nonobvious flaws. References, which explain this much better than I did: http://www.vad1.com/lab/full-eavesdropping-2011/ http://www.vad1.com/lab/full-eavesdropping-2011/ http://www.nature.com/ncomms/journal/v2/n6/full/ncomms1348.html http://www.nature.com/ncomms/journal/v2/n6/full/ncomms1348.h...