Abstract

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.

© 2002 Optical Society of America