For Liars and Loafers, Cellphones Offer an Alibi

[Thomas Shaddack]

> At 12:41 AM 6/27/04 -0500, J.A. Terranson wrote:
> >On Sat, 26 Jun 2004, Major Variola (ret) wrote:
> >
> >> At 11:56 PM 6/26/04 -0500, J.A. Terranson wrote:
> >> >
> >> >Hrmmm... Cell Phone.  TEMPEST Case.
> >> >
> >> >What's wrong with this picture???
> >>
> >> 1. You can't receive calls.  Only make outgoing, from a location
> >> which is known to fascists.
> >
> >Let's try again.  TEMPEST sheilding and outgoing calls are not
> >compatible.
>
> Of course outgoing is impossible inside the TEMPEST box.
> But you don't reveal the intermediate locations you drove
> through to get to where you broadcast.

For this purpose, plain power-off should be enough.

The "RF fingerprinting" I mentioned earlier is a different grade of threat
though; against that, shielding is necessary.

> >> 2. Use it for your toll-road-transponder too.
> >
> >And you own one, why?
>
> I don't, because I'm a cheapo and professional paranoid.  But in my
> 'hood, there are many tollroad which use them.  Otherwise you have
> to stop and toss coins.  Of course your license and face are video'd
> anyway.
>
> If I had one, I would box it unless I was driving on a toll road.

There are two kinds of tags, active and passive. Active ones have their
own power supply on board and transmit on their own, passive ones need
external field to feed them with power.

A good thing could be a detector of the passive tag readers; similar to
car radar detectors, just on different frequencies.

A detector of active tag readers should be possible to design as well;
the receivers are usually designed on the superheterodyne principle, and
the leaks of their oscillators can be detected from distance. In some
countries/states police uses detectors of radar detectors working on this
principle, and there is also some project of advertisement corps to
receive the leaks from the car radios and figure out the major demography
of the population using a given road and set the "most suitable" face of
the billboards on that road for that particular target group. So the
technology is already out there, just has to be opensourced for public
benefit.

Shame on my lack of RF skills necessary to do this :(((