Delayed-choice quantum cryptography

Evan Jeffrey, Matthew Brenner, Paul Kwiat

Research output: Contribution to journalConference articlepeer-review


Quantum cryptography is a method of communicating securely, the secrecy of which is guaranteed by the laws of physics and information theory. Current implementations suffer from relatively short ranges and low data rates. We are developing a system that modifies the usual protocol by incorporating elements of special relativity. The result is that in principle, every detected photon can be used in the final key, thus doubling or tripling the possible data rate. Our delayed-choice quantum cryptography (DCQC) system works by storing the photon sent to Bob in a low-loss optical delay line until a classical signal from Alice informs him which measurement basis to use.

Original languageEnglish (US)
Pages (from-to)269-279
Number of pages11
JournalProceedings of SPIE - The International Society for Optical Engineering
StatePublished - 2004
EventQuantum Communications and Quantum Imaging - San Diego, CA, United States
Duration: Aug 6 2003Aug 8 2003

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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