[guardian-dev] detecting mobile phone location

[Lee Azzarello]

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On 2/11/14, 9:20 AM, Matej Kovacic wrote:
> Hi,
> 
> I have a contact with one of the human rights activists in Sudan.
> The person told me a story, that some Somalian indigenous people,
> who are opressed by the Sudanian regime did the test with mobile
> phones.
> 
> They turned the mobile phone on, put it on some corner and went
> several hundert meters away. In an hour airplane came and bombed
> the house.
> 
> I am quite curious how is that possible if there is no mobile
> signal there. Of course, I don't know the details, it is possible,
> that mobile signal is there. As far as I know, it is possible to
> connect to a base station from up to 30 km away, but I am not sure
> how triangulation works if there is only one base station nearby.
> 
> Now they have a question: how to protect from this? They came with
> an idea that they will simply remove SIM card and communicate via
> wi-fi. System would create with meshing network where each mobile
> phone would be a relay node.
> 
> There is an application from Swiss mountain rescue service called
> Uepaa (http://www.uepaa.ch), which is doing similar thing.
> 
> There is also interestin slovenian project doing this with home
> wi-fi routers: https://wlan-si.net/en/ and
> https://nodes.wlan-si.net/.
> 
> However, I am not sure how safe is this (removing SIM card),
> because even if you remove SIM card, you are still able to make an
> emergency call, which means you still see the network and network
> still can see you. I think all radio part should be completely
> switched off / removed.
> 
> However, there is a problem how to do this...?
> 
> Any idea how to privide safe communications in such a case?
> Because encryption is not a solution, problem is location privacy.

Radio Direction Finding (RDF) has a rich history that predates mobile
phones. A solution to provide safe communications when a radio is an
active target for an air strike is not to use a radio to communicate.

At the very least use the radio only for some kind of store and
forward system whereby the user may transmit a message and immediately
power down the radio after transmission.

- -lee


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