From: Bill Stewart <stewarts@ix.netcom.com>
Date: Wed, 31 Jan 1996 22:40:27 +0800
To: prmoyer@magpage.com (Philip R. Moyer)
Subject: Re: encrypted cellphones
Message-ID: <199601310810.AAA00261@ix10.ix.netcom.com>
MIME-Version: 1.0
Content-Type: text/plain


At 07:18 PM 1/30/96 -0500, prmoyer@magpage.com (Philip R. Moyer) wrote:
>Well, I'm discouraged.  I'm looking for strongly encrypted cellular telephones,
>but I can't seem to find many.  
Are you looking for cellphones, or cordless phones?  There aren't a lot of
strongly encrypted cordless phones out there, but there may be some.
Digital spread spectrum is probably the best that's easy to find;
other kinds of "digital" phones usually pick a not-too-busy frequency
and transmit digitized voice, which is mildly secure against other people
using your base unit to make their phone calls, but doesn't protect your
privacy against anyone with digital-capable equipment.

The middle ground between cordless phones and cellphones includes
cordless phones with ranges of about a mile (AT&T and some other vendors
have sold them); they're typically in the $300-500 range, and use
spread spectrum to avoid interference to/from other phones.
It also includes phone services that can handle portable phones that
you have to stay in one place to use (i.e. once you start your phone call,
if you go out of range your call gets dropped rather than handed off 
to another cell.)  I'm not aware of commercial service like this in the US,
but there are wireless PBXs that work this way (which can be cheaper than
stringing phone wires around buildings.)

Cellphones, of course, can only (usefully) use encryption if the
cellular service provider uses it (i.e. if the end that's listening
to your radio transmission can decode it :-)  American cell-phone 
providers don't.  The GSM phones used in much of the world have encryption,
but it's apparently not very strong.

>I would really like to avoid using a GAK enabled product,
>if there's any way to avoid it (even if it means paying lots of extra $$$).

I'm not aware of any GAKed cordless phones, though I supposed there could be
such.
US cellular phones don't need GAK because the government's strong-armed the
standards committees into using appallingly trivial crypto - none of this
strong 40-bit RC for you :-)
#--
#				Thanks;  Bill
# Bill Stewart, stewarts@ix.netcom.com, Pager/Voicemail 1-408-787-1281
# http://www.idiom.com/~wcs