[2425] in cryptography@c2.net mail archive
Re: Existing digital phone encryption
daemon@ATHENA.MIT.EDU (sinster@darkwater.com)
Tue Mar 31 14:07:07 1998
Date: Tue, 31 Mar 1998 10:59:07 -0800 (PST)
To: cryptography@c2.net
In-reply-to: <199803310926.TAA19773@avalon.qualcomm.com> (message from Greg
Rose on Tue, 31 Mar 1998 19:26:55 +1000)
From: sinster@darkwater.com
Sprach Greg Rose <ggr@qualcomm.com>:
> Jeff Simmons writes:
> >> >I've just gotten a digital cellular phone. One of many options is to
> >> >turn on digital encryption that supposedly kicks in whenever I talk to
> >> >another digital cell phone.
>
> There is a misapprehension here. Cell phones only
> ever talk to base stations;
[...]
That's not quite true. Nextel is selling a phone that not only operates
as a "traditional" cellphone (using their proprietary protocol), but it
can also work as sort of a channelled walkie talkie (broadcast with a DCS-like
channel identifier) or direct phone-to-phone radio (also broadcast, but
there's some kind of channel-sharing going on with destination identifiers
in the packet header). Range for direct communications are pretty short
(~ 1 mile), but you have the option of purchasing repeaters from Nextel
(which are effectively the same as the base stations that Nextel uses, but
they aren't hooked up to a landline) to extend the range. I'm not too
certain of the details.
I am certain, however, than these phones aren't usable outside of Nextel
areas (read: no roaming).
Theoretically Nextel phones have some kind of ultra-spiffy encryption thing
going on, but that news comes from their marketroids, so it's not trustworthy.
I haven't even attempted to look up the details of this.
These phones are used by a lot of tech companies in the SF Bay Area who have
multiple sites and want their IS personnel to be able to keep in touch easily
across sites. I've also heard of PacBell (phone company) and PG&E (gas and
electric utility company) using them in limited circumstances to keep in
contact with field people (though I don't know why PacBell wouldn't just use
buttsets in all cases, or since PacBell has recently gotten into the cellphone
service business, those).
Of course, pedantically speaking, when the nextel phones are operating
phone-to-phone, they aren't really cell phones.
--
Jon Paul Nollmann ne' Darren Senn sinster@darkwater.com
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