[Cryptography] jammers, nor not

[Tom Mitchell]

On Tue, Feb 28, 2017 at 9:32 AM, Donald Eastlake <d3e3e3 at gmail.com> wrote:

> On Tue, Feb 28, 2017 at 9:06 AM, mok-kong shen
> <mok-kong.shen at t-online.de> wrote:
> > ....
> >
> > I vaguely remember to have read in a book that in US a permission
> > is needed to have a Faraday-shielded conference room.
>
> I think your vague memory is wrong because that is not true.


Quantifying the level of shielding deployed or needed is hard.
It is almost easy to build a shielded room or home inadvertently.

In a home..
Tall silvered mirrors are RF opaque and RF reflective for the most part.
Stucco construction is RF opaque and dissipative for the most part more if
wet.
Aluminum and copper screens on windows are RF opaque.
Aluminized vapor barriers of insulation hobble RF signal qualities.

https://en.wikipedia.org/wiki/Tempest_(codename)   <--- classified makes
this incomplete.

It is almost easy to build your own...
Products like:

Super Shield™ Nickel Conductive Coating
COPPER SHIELD - 45% COPPER ABLATIVE  <-- marine
Conductive Shielding Paint <-- guitar making pickup shielding
RFI-EMI Aluminum Shielding Sheet, Polyester w/Al, W/L/T

make it easy to shield largish volumes.
My favorite is Stainless steel wool for shielding.
  PestPlug is made from 100% RUST FREE Steel Wool
Aluminum foil is not as effective as one might guess.
Tin foil hats have been tested.
https://www.theatlantic.com/health/archive/2012/09/tin-foil-hats-actually-make-it-easier-for-the-government-to-track-your-thoughts/262998/

It is hard to get it right..
If you are serious there is a lot of work, testing and retesting involved.


-- 
  T o m    M i t c h e l l
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