[liberationtech] more on sat phone (in)security

[Bernard Tyers]

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Hi there,

Just a few points:

Martyn: while you are right on most cases about amateur radio, I agree with Jacob's main point (as I understand it, please correct me if I am incorrect) that there other technologies that can be used. It does not have to be "the most complex". It can be argued, the more complex the system, the more unusable it becomes due to more requirements.

Leaving the legal requirements for licensed amateur radio emissions to be in cleartext, the amateur radio spectrum is quite large. Again leaving aside the ITU regional differences the spectrum ranges from LF (130KHz approx) right up to EHF (250GHz). It gives you certain amount of area to hide in.

Jamming amateur radio frequencies is as trivial with the right equipment (and money) as jamming GSM, UMTS, satellite transmissions.

Concerning amateur operators not being appreciative of unlicensed; from experience amateur radio operators are very open to humanitarian missions using (and possibly misusing) their licensed spectrum. There are worldwide networks of ham operators who man, 24/365 voluntary radio emergency networks (REN) for passing humanitarian messages to/from involved parties. There is an article on wikipedia (light on technical facts unfortunately) which expands on the global nature of ham emcomm nets. [1]

The use of ham radio for clandestine uses has been documented for years, an example being during the invasion of Kuwait. [2], [3]

One approach (not amateur radio related), which I have not thought through from the point of view of technical feasibility, would be the approach used by numbers stations. They transmit their messages in seemingly random strings. It is true they use HF spectrum, use powerful transmitters and large antennae, but to my knowledge their messages have never been deciphered. Of course, it may be possible government agencies have, but it has not come to the media.

Some also use distributed antenna arrays, relaying the signal over hundreds of kilometres thus obscuring the source of the emission,and making jamming practically impossible (it is assumed). [4] Again this requires certain infrastructure to be in place.

If this approach was possible in a more portable nature, and the call finally being sent to the satellite after multiple relays, this may be an option.

The core of the issue here is that every RF emitting device is vulnerable to location discovery. The only secure approach to these technologies is not use them.  An approach could be to prepare the message in offline mode, go to a new location which gives you coverage. Go online with the device, send the message. Turn the device off, and leave immediately. And never go back to that location plus X Km radius. Of course you end up running out of areas to transmit from, but again they are the constraints.


regards,
Bernard


[1] http://en.wikipedia.org/wiki/Amateur_radio_emergency_communications
[2] http://en.wikipedia.org/wiki/History_of_amateur_radio
[3] https://www.meforum.org/238/the-kuwaiti-resistance
[4] http://en.wikipedia.org/wiki/Numbers_station#Attempted_jamming_of_number_stations


On 24 Feb 2012, at 06:04, Martyn Williams wrote:

> Jacob,
> 
> I don't see how using amateur radio wouldn't be an improvement over
> satellite phones. The antennas and power levels involved would almost
> certainly be larger.
> 
> Plus, where would you receive the signals? If you want to use mobile
> transceivers then your range is limited so receiving stations would have
> to be set up over the border.
> 
> If you want to transmit something back to, say, London then you're
> talking about a fixed station that requires an outdoor, fixed antenna
> and a battery backup system for uninterrupted use.
> 
> Jamming would be easy - anyone with an off-the-shelf transceiver could
> find your signal and key-up on top of you.
> 
> I would bet that amateur stations are easier to direction-find than
> satellite phones. In fact, direction finding is a popular hobby for some
> hams and methods, technologies and equipment is widely understood.
> 
> Licenses don't allow commercial use or encryption, although this might
> not be a problem. Presumably they wouldn't be licensed to operate in the
> countries anyway. Amateurs probably wouldn't appreciate unlicensed and
> unapproved use of their frequency bands by journalists.
> 
> Martyn
> 
> On 02/23/2012 05:36 PM, Jacob Appelbaum wrote:
>> On 02/23/2012 05:17 PM, Brian Conley wrote:
>>> Unfortunately they are often the only option. I think there needs to be a
>>> radical rethinking of international law as well as efforts to provide
>>> journalists ict support without relying on opposition activists which is
>>> inherently dangerous.
>> 
>> This is an education problem. You could always use a HAM radio - at
>> least it is well understood technology - right?
>> 
>> There are ALWAYS other options.
>> 
>> All the best,
>> Jacob

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