2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/217117A working free-space quantum key distribution (QKD) system has been developed and tested over an outdoor optical path of ~1 km at Los Alamos National Laboratory under nighttime conditions. Results show that QKD 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 QKD.5 pages, 2 figures, 2 tables. Submitted to Physics Review Letters, May 1998Quantum Physicstext