Re: [Cryptography] Help investigate cell phone snooping by police nationwide
(or as Snowden demonstrated, put in a fridge to avoid scrutiny and audio capture the best idea. non-serial tower associations are an anomaly alerted and acted upon.)
Faraday cages concept really depend on the freqs they are designed to inhibit, pressure, sound, radio, optic, etc. Given wide enough freqs, one cage does not service all. A fridge has plastec and magnetic gaskets, over maybe 2cm variant gap, so not a complete EM seal (at whichever specifical freqs). And grounding issue. But good at human sound deading. Microwave door shield is closer to cell phone freq shield. If you cannot simply remove the battery preferably, that is. As always, test first. And is easy to find phones to test all phone bands with. TEMPEST.
From: grarpamp <grarpamp@gmail.com>
(or as Snowden demonstrated, put in a fridge to avoid scrutiny and
audio capture the best idea. non-serial tower associations are an anomaly alerted and acted upon.)
Faraday cages concept really depend on the freqs they are designed
to inhibit, pressure, sound, radio, optic, etc. Given wide enough freqs, one cage does not service all. A fridge has plastec and magnetic gaskets, over maybe 2cm variant gap, so not a complete EM seal (at whichever specifical freqs). And grounding issue. But good at human sound deading. Microwave door shield is closer to cell phone freq shield. If you cannot simply remove the battery preferably, that is. As always, test first. And is easy to find phones to test all phone bands with. TEMPEST.
Why not wrap the phone in a couple of layers of aluminum foil? (Although, it won't shield against audio if that's being recorded even while an RF contact does not exist...) Jim Bell
On Sun, Jun 8, 2014 at 1:04 PM, jim bell <jamesdbell9@yahoo.com> wrote:
Why not wrap the phone in a couple of layers of aluminum foil? (Although, it won't shield against audio if that's being recorded even while an RF contact does not exist...)
The thread referred to refrigerators and microwaves. Yes even an ungrounded single layer aluminum foil bag with singlefold seam is able to block phones here. Test as desired. Unlike the former devices, foil is also light and easily carried for travel anywhere if battery is hardwired and/or you don't trust 'off' button. Also things like evercap and RF id/power may play in some devices.
The order of optimality: 1. no cell phone no how 2. cell phone with battery removed 3. disinformation feed 4. faraday cage for otherwise operational phone Film at 11, --dan
participants (4)
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dan＠geer.org -
grarpamp -
jim bell -
Peter Gutmann