From: "Peter Trei" <trei@process.com>
Date: Sat, 16 Dec 1995 13:45:21 +0800
To: cypherpunks@toad.com
Subject: Re: Motorola Secure Phone
Message-ID: <9512160230.AA27216@toad.com>
MIME-Version: 1.0
Content-Type: text/plain


Sameer wrote
> 
> 	My AT&T 900 (or is it 9000?) MHz digital cordless phone says
> the same thing. I figure it uses a weak cryptosystem. There is
> something about key setup when you return the handset to the base.
> 	(The phone was $200, FWIW)
 
> Dan wrote: 
> > I saw a new cordless phone made by Motorola in a retail outlet today
> > that is supposedly "Secure from eavesdroppers."  I asked the
> > salespeople for more technical info, but they weren't very helpful. 
> > Does anyone have any information on this?  I didn't notice any "Not
> > for Export" stickers on the box, and the ITAR does cover
> > spread-spectrum technology.  So is it analog or digital?  Is it just
> > doing simple analog tricks, or is it encrypting a bitstream?  Clipper
> > maybe?  I doubt it.  Any info appreciated.
> > 						Dan

    I've also got an ATT 9000. It's one of the digital 900Mhz phones, and
has no encryption.  It claims extra security due to being digital - your
average 14 year old's scanner is analog only. 

    There's a bunch of frequencies. The frequency to use, and 
(fairly small (16bit?) security code gets reset when the receiver is
put on it's stand. The code is used only for a handshake, so several
phones in the same area won't interfere by accident. It is not 
frequency agile - the same freq is used throughout the call. 

    It's a good phone - nice tone, long range, and it's secure
against jerks with scanners. Secure against serious eavesdroppers
it's not.

    When I bought it a year or so ago, I also looked at another phone
from (I think) Uniden, which *was* frequency agile. I was intrigued
enough to call the manufacturer, and confirmed that it did indeed
hop frequencies while the call was underway. How often, and
how the next frequency was determined was not known by the 
guy I talked to, and I balked at the $350 price. 

speaking for myself

Peter Trei
trei@process.com

Peter Trei
Senior Software Engineer
Purveyor Development Team                                
Process Software Corporation
http://www.process.com
trei@process.com