[cryptography] [Cryptography] Help investigate cell phone snooping by police nationwide

Natanael natanael.l at gmail.com
Sun Jun 8 16:02:42 EDT 2014


Den 8 jun 2014 21:52 skrev "Jerry Leichter" <leichter at lrw.com>:
>
> On Jun 7, 2014, at 7:56 PM, Bill Cox <waywardgeek at gmail.com> wrote:
>>>
>>> Is there reliable evidence that putting mobiles in a fridge is any
>>> better illusory comsec than putting pillows around the door also
>>> comically exhibited to clueless journalists favored by Showman
>>> Snowden? Or at least as tall-taled by comical Glenn.
>>
>> It's called a Faraday cage.  I'd test it right now, but I think someone
hid my mobile phone in a fridge.
>
> The problem is that a refrigerator is not a Faraday cage.  Every
refrigerator I've ever used has rubber gasket between the door and the body
of the refrigerator.  It's typically 2-3 cm thick.  Cell phone wavelengths
vary with band, but range from somewhere around 30 cm down to around 8 cm.
 A refrigerator should attenuate the signal, probably quite a bit, but it's
not going to block completely.
>
> Of course, this assumes that the point of the exercise is to block the
RF.  A refrigerator will also, to some degree, block sounds.  Since nothing
inside the food box of a refrigerator typically generates any noise (and of
course it's not *sensitive* to noise either), there's no reason to design a
refrigerator to be soundproof.  So how much it will muffle outside sounds
is unclear.
>
> These things are easy to check experimentally, at least to a good enough
approximation to say whether they are likely to be effective for the task
at hand.  If it's important to you ... let us know how the experiments come
out.
>
>                                                         -- Jerry

That leaves my conclusion as that you should stuff the phone into pillows
in the microwave before you put the microwave in the fridge, and then
stuffing more pillows in there.

Then you wrap it all with a lot of layers of blankets and hold them in
place with aluminum foil.

Then you do the same separately for the battery. Because you removed the
battery first, right?

Should only take a single working day or so to achieve.
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