Secure communications using quantum cryptography

Richard J. Hughes, William T. Buttler, Paul G. Kwiat, Gabriel G. Luther, George L. Morgan, Jane E. Nordholt, C. Glen Peterson, Charles M. Simmons

Research output: Contribution to journalConference articlepeer-review


The secure distribution of the secret random bit sequences known as "key" material, is an essential precursor to their use for the encryption and decryption of confidential communications. Quantum cryptography is an emerging technology for secure key distribution with single-photon transmissions: Heisenburg's uncertainty principle ensures that an adversary can neither successfully tap the key transmissions, nor evade detection (eavesdropping raises the key error rate above a threshold value). We have developed experimental quantum cryptography systems based on the transmission of non-orthogonal single-photon states to generate shared key material over multi-kilometer optical fiber paths and over line-of-sight links. In both cases, key material is built up using the transmission of a single-photon per bit of an initial secret random sequence. A quantum-mechanically random subset of this sequence is identified, becoming the key material after a data reconciliation stage with the sender. In our optical fiber experiment we have performed quantum key distribution over 24-km of underground optical fiber using single-photon interference states, demonstrating that secure, real-time key generation over "open" multi-km node-to-node optical fiber communications links is possible.

Original languageEnglish (US)
Pages (from-to)2-11
Number of pages10
JournalProceedings of SPIE - The International Society for Optical Engineering
StatePublished - 1997
Externally publishedYes
EventPhotonic Quantum Computing - Orlando, FL, United States
Duration: Apr 23 1997Apr 23 1997


  • Interferometry
  • Optical communications
  • Quantum cryptography

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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