FC2Video

The NIST quantum key distribution (QKD) system uses single photons, the smallest particles of light, in different orientations to produce a continuous binary code, or "key," for encrypting information. The rules of quantum mechanics ensure that anyone intercepting the key is detected, thus providing highly secure key exchange. The laboratory system produced this "raw" key at a rate of more than 4 million bits per second (4 million bps) over 1 kilometer (km) of optical fiber, twice the speed of NIST's previous record, reported just last month.** The system also worked successfully, although more slowly, over 4 km of fiber.

more info
http://www.nist.gov/public_affairs/releases/quantumfiber.htm
captioned video avaliable