Denning's Geo-crypto

[John Young]

Google shows one "geo-encryption" patented by CoinCard,
which may or may not be a component of Denning's geo-crypto.
Because CoinCard is a Canadian company, its geo-encryption
may have nothing to do with Denning's.

CoinCard uses a system composed of a swipe card and passive 
card reader to decrypt, described in a programmers' manual:

  http://www.coincard.com/download/ProgrammerManual.pdf

It looks as though these readers could be rigged for GPS 
transceiving to assure that encrypted data was physically 
located where intended by the sender, and/or the recipient's 
card could be programmed to be read only by that card reader.

Is this a novel system? How to spoof GPS location? Can
bin Laden be in several caves around the world each equipped
with a personal-ID GPS passive transceiver? Do caves
serve as acoustic resonators to emit recorded whispers up 
ventilating shafts?

What underling was wearing Rumfeld's personal tracker on
9/11? Why was the SecDef frantically trying to recover it before
Mrs. Rumfeld's private investigators? And his secondary
tracker?