At 12:04 AM 9/14/00 +0800, Enzo Michelangeli wrote:
>September 10 2000 BRITAIN
>
>Army calls up mobile phones
...
>They can also be listened to more easily than radios, although Clansman's
>antiquated technology makes it almost as vulnerable to interception. Mobiles
>can also be tracked easily and are far more expensive to operate.
I don't know much about the internals of current cellphones, but it's not
like it would be hard to build a secure cellphone service on top of
existing cellphone systems. You just design it so that each phone gets a
shared secret with some call center, and all calls go through the call
center, which does the symmetric key exchange for the two phones. (For
extra credit, you can do a PKI, which will work well in this environment.)
I suspect the real problem here is that once enough soldiers are using the
local cellphone system, an enemy can either selectively deny service (it
can't be too hard to listen for digital data, or even for data that
consistently doesn't compress well, and kill those calls), or can just blow
up, or cut power to the cellphone towers. This would be especially nasty
in the middle of some attack, where suddenly the communications system
stops working when you need to call for help or tell someone who's shooting
at you to knock it off.
I wonder how hard it is to maintain independent cellphone service via
temporary towers or something.
>Although the Ministry of Defence claims mobile phones are never used in
>combat areas there have been signs that this rule is not always adhered to.
>In Kosovo, British Army commanders borrowed journalists' mobile phones to
>speak to Serbian leaders during the conflict, according to confidential
>reports, because up to a third of personal radios were broken.
I think this is mainly an example of adding options for communications all
around. If there's a local wired phone system, cellphone systems,
satellite phone systems, and wireless LAN services all around, then it's
likely you can find *something* that works. (This works unless you've
already blown up all the infrastructure for that stuff.)
Of course, we need to have strong crypto deployed for all this stuff. It's
really going to suck some time in the future, when the bad guys intercept
the phone call for help from the British soldiers, and either get there
first or set up an ambush for the rescuing forces. (But, of course,
civilian communications don't need *real* security, right?)
--John Kelsey, [EMAIL PROTECTED]
