On Thu, 22 Nov 2001, Roy M. Silvernail wrote: > Using a GPS coordinate set as keying material? Hope it's just
Given that a GPS receiver gets ephemeris data, almanach data and pseudorandom code from each currently visible sat it has probably to do with the latter. Consider S/A (which may or may not be switched off now, I haven't checked): if you've got a secret part of the key you can refine your position despite deliberate degradation (selective availability) than the party without the key. > additional keying material. Knowing the intended destination of > something like a movie in transit to a theater seems pretty easy, and > the set of GPS coordinates encompassing your average multiplex would > seem to be pretty small compared to the usual keyspaces discussed > here.
