Quantum key distribution over distances as long as 30 km
C. Marand, Paul D. Townsend · Optics Letters · 1995
We report the secure transmission of cryptographic keys over as long as 30 km of optical fiber, using an interferometric quantum cryptography scheme. Low error rates in the range 1.2–4% were obtained for the quantum transmissions, and error-free secret keys were distilled from the raw data by use of secure error-correction and privacy-amplification protocols.