Currently, many of the digital cell phones are using CDMA (code division multiple
access), or TDMA. TDMA (tone division multiple access) is an older technology
and CDMA is the preferred digital technology the cell phones use to communicate.
With CDMA the information is already sent in packets, it would not be
difficult,from the programming I've worked on in this area at least (VA) to
structure it the same way you would to PKI with network packets. Of course
Europe already has smart card phones being used.
--
Kevin Blanchard Operational Research Consultants, Inc.
[EMAIL PROTECTED] 1625 Prince Street, Suite 250
Phone: (703) 535-5344 Alexandria, Virginia 22314
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John Kelsey wrote:
> 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]
