Re: optical spread spectrum, I seem to remember either inventing or hearing
about a trick with quantum wells that ought to let you create something very
like a free-electron laser.
I nicknamed this a "caged-electron laser".
These ought to be insanely efficient and might even be structurable as phased
arrays, active countermeasures like the ones rumored to be in place on the B-2
and FB-117*, etc.
* I forget what that technology is called; it's the one where the material
itself is primed and constructed with wideband rectifiers, dipoles, and other
circuitry peppered through its bulk so as to return a spoof signal with zero
processing delay--anyone out there remember the name of it? ...only on the nano
level.
BTW, Crit is up, and it rocks.
Steve Witham wrote:
> I think it is necessary to have redundant information for clock syncing and
> error recovery. But, if the things we believe about cryptography are
> true--that there are "hard problems", for instance--then the overhead can
> be small and the result can still be impossible to distinguish from noise--
> even though there is redundancy, it's a hard problem to see it.
>
> There is that funny comment in A Fire Upon The Deep where (as we the
> readers are being treated to a boring slow-motion chase across the
> galaxy) two characters pass the time by debating the feasibility of public
> key cryptography (or any scheme except one-time pads generated with true
> randomness)...
>
> Quantum stuff throws wildcards into predictions about computability &
> also provides quantum crypto possibilities, so things could look different,
> even pretty soon.
>
> But as far as I know you can make redundant information look like noise.
>
> (later) Oh, PHIL started this thread!?
>
> Also, like Phil says, you can make your signal have any spectrum you want
> and probably be sloppy about things that people with only terahertz
> technology can't detect--if they're who you're trying to hide from.
>
> *The Diamond Age* had those nanites with light-wavelength communication
> that appeared as colored sparkles. You don't have to actually wiggle the
> nuclei to control photons. Light waves are pretty long in nanometers--
> ~600-1200nm?
>
> I guess interstellar stealth will be
> mainly developed to hide from *local* enemies--people from your own
> planet with technology similar to or somewhat better than yours.
> You could extend "Good fences make good neighbors" to "Interstellar
> civilizations only spread as far & fast as their crypto technology
> makes safe from internal corruption." (Which is verbose but you
> could probably pack it into <1024 bits.)
>
> I hereby signify my recognition that this is science fiction based on
> science fiction.
>
> --Steve
>
> --
> sw@tiac.net Steve Witham www.tiac.net/users/sw under deconstruction
> "...when activated, it pops a message off the bag
> and recurs with the tail of the bag."
> --Vijay Saraswat and Patrick Lincoln
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