Re: Johnny Mnemonic

From: Rob Warnock (rpw3_at_rpw3.org)
Date: 10/31/03 

Date: Fri, 31 Oct 2003 09:56:33 -0600

G. Orme <newsgroups@harmakhiss.org> wrote:
+---------------
| I just read the story and screenplay, that was made into the well known
| movie with Keanu Reeves. In the story Johnny takes 3 snapshots of a TV
| signal each from 3 different channels and uses that as a key to encode the
| data he carries, 320 gig of it.
| The same 3 snapshots are sent to the receiver separately for decryption
| later. Is this a sensible idea, I assume it is something the author William
| Gibson thought up.
+---------------

Maybe, but he's hardly the only one to use the idea. Vernor Vinge's
excellent SF novel "A Fire Upon The Deep" contains the same concept
as an oft-mentioned plot element, namely, that a simple way to improve
the security of physically distributing OTP material is to generate
*lots* more pad material than you really need, break it up, and send
it via several *different* transportation paths [different ships,
routes, couriers, etc.]. Alice & Bob then communicate by XOR'ing
sections of pads sent by different routes, and using *that* as the
actual pad for their OTP communications. Even if Eve intercepts & copies
one or more of the different versions, as long as she doesn't get *all*
of them the communication between Alice & Bob will still be secure.

Vinge suggests that "3" is a good number of different couriers/routes
to use. That seems like a minimally-adequate number. More would be better,
of course, but the costs go up proportionately, and some pairs of sources
and destinations may not *have* a plethora of alternate routes available
between them for the couriers/cargo to take.

[Another poster replied that Gibson had his character take all three
TV signals *himself*, which is of course a flagrant violation of the
"independent couriers & routes" principle Vinge espouses. I'll go with
Vinge's method, myself...]

-Rob

-----
Rob Warnock <rpw3@rpw3.org>
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