Single Photon Quantum Key Distribution AchievedCategory: Science & Technology
Posted: August 15, 2012 02:19PM
Man has been telling secrets for probably as long as we have been able to tell each other anything, and for almost as long, we have been trying to eavesdrop. A war has since started to keep secrets hidden with codes, encryption, and other methods, but these methods still require sharing a key that cannot be protected (locking your keys in your car may keep people from breaking in, but then you cannot get in either). Quantum Key Distribution (QKD) however uses the laws of quantum physics to protect the keys, so if anyone who should not interact with them does, the legitimate parties know.
As reported by the Institute of Physics, researchers in Wuerzburg, Munich, and Stuttgart have successfully transmitted a quantum key using a single photon source from two semiconductor nanostructures. Previous attempts to send such keys have often relied on lasers which randomly emit photons. This means multiple photons could be produced, and thereby multiple keys, which would enable an eavesdropper to listen in without being detected. Single photon sources prevent there from being duplicate keys and increase security.
Sadly this technology is not quite ready for real-world use, as this experiment only sent the photons 40 cm. That is not far enough to be of much use right now, but numerous teams around the world are working on this and related technology.