Free-space quantum key distribution at night

W. T. Buttler, R. J. Hughes, P. G. Kwiat, S. K. Lamoreaux, G. G. Luther, G. L. Morgan, J. E. Nordholt, C. G. Peterson, C. M. Simmons

Research output: Contribution to journalConference articlepeer-review


An experimental free-space quantum key distribution (QKD) system has been tested over an outdoor optical path of ∼ 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 two-dimensional 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.

Original languageEnglish (US)
Pages (from-to)14-22
Number of pages9
JournalProceedings of SPIE - The International Society for Optical Engineering
StatePublished - 1998
Externally publishedYes
EventPhotonic Quantum Computing II - Orlando, FL, United States
Duration: Apr 15 1998Apr 16 1998


  • Bennett 92
  • Cryptography
  • Eavesdropping
  • Error Detection
  • Information Security
  • Parity Check
  • Privacy Amplification
  • Quantum Cryptography
  • Quantum Key Distribution
  • Satellite

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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