Fwd: [cryptography] The Compromised Internet

Eugen Leitl eugen at leitl.org
Thu Sep 26 08:02:18 PDT 2013


On Thu, Sep 26, 2013 at 09:20:43AM +0200, Lodewijk andré de la porte wrote:
> 2013/9/26 Eugen Leitl <eugen at leitl.org>
> 
> >  It's really hard to jam the sky, especially in VIS range.
> >
> 
> "Huh. Guys, what's that on our radio scanner? Someone calls us?"

They want to pick up a parabolic dish, a LoS laser or a
phased array tracking a point source overhead, all sending
at maybe 5-10 W power? 

Sure, if your sky is thick with mapping drones. Sounds like
a fifth world problem.

> Hard to jam, easy to trace. Even regular Dutch police forces have
> triangulation tactics to find pirate radio stations.

Isotropic radiators with high power are easy to spot.
Dynamic tight beams need at least a passing point of alignment
to get a position fix on the ground station. NSA sigint
used that microwave LoS interception, but this wouldn't
scale for millions of users and very brief low-power
bursts during random alignment events.
 
> This is where I'm more enthusiastic about near-optical connections. A
> laser, invisible spectrum ofc, and a small black surface (iow:detector) are
> all it takes. It will still be visible (at night) with special hardware.
> Street lanterns (depending on the type) might make them invisible at night
> too. Bandwidth is wonderful, and there's plenty of spectrum to duplicate
> bandwidth too. Quite like fiber, except for the ideal transmission.

Or maybe you just buy http://www.ubnt.com/airfiber or the lower-grade
gear for LoS.
 
> And that highlights the problems. You have to keep the laser pointed, that
> means not diffracted by thermic differences or blocked by dust and other
> particles (like, you know, leaves). This might be less trouble than it'd
> seem at first, and even better it can be automated by a lens system.
> 
> A just graduated ship's lieutenant laughed at me for suggesting laser
> communication as the future. "No spying, very high speed, very wide
> bandwidth!" and he effectively answered "Line of sight, irreliable, no need
> for speed and just use satellite".
> 
> A yagi pointed skywards should be hidable inside the house, so I guess he's
> somewhat right.

Phased arrays which are flat or half domes are compact and don't
look like anything from air. If you're clever, you can integrate
these into a PV panel. 
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