-----BEGIN PGP SIGNED MESSAGE----- In article <Pine.BSF.3.91.960723170725.23791A-100000@mcfeely.bsfs.org>, Rabid Wombat <wombat@mcfeely.bsfs.org> wrote:
ob crypto/privacy: Anybody have a good idea for detecting a tap on exterior fiber? I'd expect an attacker to have to interupt connectivity, terminate both ends of a break, and insert an active device. Thoughts?
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. 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. - -- Alan Bostick | [Spielberg's] latest is TWISTER, a film that mailto:abostick@netcom.com | gives whole new meaning to the phrase "giant news:alt.grelb | sucking sound." -- Patrick Taggart http://www.alumni.caltech.edu/~abostick -----BEGIN PGP SIGNATURE----- Version: 2.6.2 iQB1AwUBMffDPeVevBgtmhnpAQHftwL9HTNe4VUHlpRkOAYW1nKFwyw3cqkM+xXt +zXOHuR52ffP1M2IZwTnPpBrBaXlCa6W+3uahnczVdJmAR/0MF5ksnh6bpjd+9IP KmqnBG52X8f+HazUEygNJkRD1oVGlMTH =FHZ5 -----END PGP SIGNATURE-----