Free-space quantum key distribution at night
W. T. Buttler, Richard Hughes, Paul G. Kwiat, S. K. Lamoreaux, G. G. Luther, George L. Morgan, J. E. Nordholt, Charles G. Peterson, Charles M. Simmons · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1998
An experimental free-space quantum key distribution (QKD) system has been tested over an outdoor optical path of approximately 1 km under nighttime conditions at Los Alamos National Laboratory. This system employs the Bennett 92 protocol; here we give a brief overview of this protocol, and describe our experimental implementation of it. An analysis of the system efficiency is presented as well as a description of our error detection protocol, which employs a 2D parity check scheme. Finally, the susceptibility of this system to eavesdropping by various techniques is determined, and the effectiveness of privacy amplification procedures is discussed. Our conclusions are that free-space QKD is both effective and secure; possible applications include the rekeying of satellites in low earth orbit.