Long-distance record -- 'Quantum keys' sent 200 kilometers

Particles of light serving as “quantum keys”—the latest in encryption technology—have been sent over a record-setting 200-kilometer fiber-optic link by researchers from the National Institute of Standards and Technology (NIST), NTT Corp. in Japan, and Stanford University. The experiment, using mostly standard components and transmitting at telecommunications frequencies, offers an approach for making practical inter-city terrestrial quantum communications networks as well as long-range wireless systems using communication satellites.