Practical free-space quantum key distribution

W. T. Buttler, Richard Hughes, Paul G. Kwiat +6 more

A working free-space quantum key distribution system has been developed and tested over an outdoor optical path of $\ensuremath{\sim}1\mathrm{km}$ at Los Alamos National Laboratory under nighttime conditions. Results show that free-space quantum key distribution can provide secure real-time key distribution between parties who have a need to communicate secretly. Finally, we examine the feasibility of surface to satellite quantum key distribution.

Alberto Carrasco-Casado, Verónica Fernández, Natalia Denisenko

Fabian Beutel, Jasper Rödiger, Nicolas Perlot +2 more

Richard Hughes, J. E. Nordholt, George L. Morgan +1 more

We have demonstrated quantum key distribution (QKD) over a 10-km, 1-airmass atmospheric range during daylight and at night. Secret random bit sequences of the quality required for the cryptographic keys used to initialize secure communications devices were transferred at practical rates with realistic security. We infer from these results that free-space QKD will be practical over much longer ranges under these and other atmospheric and instrumental conditions.

Tapster, Gorman, Benton +3 more

Richard Hughes, J. E. Nordholt, Derek Derkacs +1 more

We have demonstrated quantum key distribution (QKD) (Bennett C H and Brassard G 1984 Proc. IEEE Int. Conf. on Computers, Systems, and Signal Processing (Bangalore, India) p 175) over a 10 km, 1-airmass atmospheric range during daylight and at night. Secret random bit sequences of the quality required for the cryptographic keys used to initialize secure communications devices were transferred at practical rates with realistic security. By identifying the physical parameters that determine the system's secrecy efficiency, we infer that free-space QKD will be practical over much longer ranges under these and other atmospheric and instrumental conditions.