How are the Baltimore riots going?/Any way we can help?

Mirimir mirimir at
Sat May 2 17:21:16 PDT 2015

On 05/02/2015 03:40 AM, Douglas Lucas wrote:
> On 05/01/2015 03:26 PM, Mirimir wrote:
>> Protesters, or at least key organizers, need to
>> be running apps to detect and block IMSI catchers. And everyone not
>> using them needs to put their phones in Faraday bags. So they also need
>> to know how to make Faraday bags from aluminum foil and duct tape.
> Good links to walkthroughs on both these would be greatly appreciated.

I don't use smartphones, and so don't know what works best. Searching on
"detect IMSI catcher" yields hits for Android, but I see no apps for
iOS. AIMSICD looks like a good app. Maybe someone who knows this stuff
well can recommend one.

For the Faraday bag, see
<>. It's easy to
test. Just put the phone in the bag, and call it. If it rings, there are

The hardest aspect is getting good electrical contact on all seams,
including the access flap. The maximum dimension of any hole in the bag
must be small, less than an inch. A gap at the seam that's an inch long,
even if it's very narrow, will leak a lot.

The other thing to keep in mind is that aluminum foil gets brittle with
bending, and will crack. So you need multiple layers, and the layers
must be in electrical contact. Narrow strips of double-stick tape
between layers are OK to provide structural stability. But it's a trade-off.

> I was at Freddie Gray et al./May Day protest tonight (Friday; see tweets
> There was one point, a
> key intersection we were marching through halfway into the march, where
> cell reception inexplicably dropped for a few minutes. There was also,
> early on, someone in an Austin Police Department hat taking
> pictures/video from the balcony of a firefighter's station, suggesting
> that the cops were clued in, which would make sense given the organizing
> happening on facebook etc., which of course sounds like horrors to
> crypto snobs but in terms of mobilizing large populations is the only
> current, repeatedly practiced answer and an effective, if dangerous, one.

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