Securing Fiber Using Light Polarization

screenbert writes: "A new and novel way of communicating over fiber optics is being developed by physicists supported by the Office of Naval Research. Rather than using the amplitude and frequency of electromagnetic waves, they're using the polarization of the wave to carry the signal. Such a method offers a novel and elegant method of secure communication over fiber optic lines. This press release has more information. Of course I always thought that fiber was always pretty secure anyway since it's a lot harder to tap than copper."

Comments

Quantum Cryptography

[kovacsp]

Quantum cryptography uses the polarization of light to transmit provably secure information. The trick is that when you receive polarized light, if you pick the wrong polarization there's a 50% chance that the light will spontaneously flip to that polarization. Thus, unless you know the correct polarization sequence (the key), as you receive the light, you will not be able to intercept the communications under even the best of circumstances.

This isn't exactly new either. Its been around since at least the 70's.

More info:
http://www.cs.mcgill.ca/~crepeau/CRYPTO/Biblio-Q C. html
http://www.cyberbeach.net/~jdwyer/quantum_cr ypto/q uantum1.htm