At 11:52 AM 7/25/96 -0700, abostick@netcom.com (Alan Bostick) wrote:
As has been mentioned earlier, all an attacker has to do is encourage some of the light to exit the fiber, by bending it, contacting it with a detector, etc. If the detector is sensitive enough, the loss induced by this is minimal. This sort of tapping is exactly the sort of thing quantum cryptography is supposed to prevent, or at least identify.
So far, so good.
Nothing short of quantum methods is going to spot the tap, unless you happen to come across the tap by inspecting the entire length of the fiber.
Pressurized conduit is a favorite paranoid technique - if the Bad Guy cuts open the conduit to get at the fiber, your alarm system notices the pressure drop and goes off. For slightly less paranoid scenarios, you can use heavy narrow conduit with epoxied joints, and the extra alarm wire or two to help detect cutting. For substantially more paranoid types, you can always fill your conduit with some sort of flammable substance that reats with air... # Thanks; Bill # Bill Stewart, +1-415-442-2215 stewarts@ix.netcom.com # <A HREF="http://idiom.com/~wcs"> # Dispel Authority!
-----BEGIN PGP SIGNED MESSAGE----- On Fri, 26 Jul 1996, Bill Stewart wrote:
Pressurized conduit is a favorite paranoid technique - if the Bad Guy cuts open the conduit to get at the fiber, your alarm system notices the pressure drop and goes off. For slightly less paranoid scenarios, you can use heavy narrow conduit with epoxied joints, and the extra alarm wire or two to help detect cutting. For substantially more paranoid types, you can always fill your conduit with some sort of flammable substance that reats with air...
for that matter, string fibers in bundles as such _ _/ \_ / \_/ \ \_/ \_/ / \_/ \ \_/ \_/ \_/ where the middle one carries the real signal, and the outer ones cary fake signals, and use them for interruption detection. --Deviant Legalize free-enterprise murder: why should governments have all the fun? -----BEGIN PGP SIGNATURE----- Version: 2.6.2 iQEVAwUBMfkxiTAJap8fyDMVAQFRBgf+NmGLsJnPRQdJTgyb+7EBwQsqy7hlDAzZ MKC1cuQY6Z4UfVBO3PR5BTygKLRp2bjhH8DIiLKP5ILk3rh8ujVfE4qlFtdQj7t0 Mq4MO5x5EmBx4fQxJfzLshPBUlkjh7jBZ9y/VQVdpWmNrf++js913O4VGQwXRI0Y 9pf3P3UaPqtgkcCmTnxmaCFgxAr5l1gwSPEcmNDmx8AfhZBd2Od/3/v6xsO2uxCz yWV3b1X5i2DxKVjx4aWlqH9uvfn8dJSw9Efi0UAnA1vX5Hn2OGufYyI05MHXsEUf Cutjtd3q/s5OSrXkAN8hjZrQ2m/34wqhtowHZ2bFJIX/vsi5hk8c1Q== =8r2J -----END PGP SIGNATURE-----
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