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Cyphernomicon 18.3

Loose Ends and Miscellaneous Topics:
Quantum Cryptography

   18.3.1. "What is quantum cryptography?"
           + Two main flavors:
             + secure channels exploiting the Uncertainty Principle
               + Brassard, Bennett, fiber optic lines, short distances,
                  detects tapping
                 + Quantum cryptography
                   - bits can be exchanged-albeit at fairly low
                      efficiencies-over a channel
                   - with detection of taps, via the change of
                   + Stephen Wiesner wrote a 1970 paper, half a decade
                      before the P-K work, which outlined this-not
                      published until much later
                     - speculate that the NSA knew about this and
                        quashed the publication
             + factoring of numbers using a strange Many World
               - Shor
               + hearkens to my spoof about Russians
                 - I never knew I hit so close to the mark!
   18.3.2. "What about _quantum cryptography_?"
           + Exploiting Uncertainty Principle to make untappable
              communication lines. (More precisely, tapped lines give
              indication of having been tapped.)
             - Bennett and Brassard
             - faint flashes of light in a fiber optic cable used;
                polarized photons
             - Alice and  Bob go through a protocol that involves them
                picking Linear or Circular Polarization (LP or CP); can't
                be simultaneously measured...
           - Not likely to be important for a long time.
           - An additional tool, or crypto primitive building block.

Next Page: 18.4 Chaotic Cryptography
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