From: Carl Ellison <cme@cybercash.com>
Date: Wed, 22 Jan 1997 21:10:47 -0800 (PST)
To: dccp@eff.org
Subject: P.S. David Kahn's editorial today
Message-ID: <199701230510.VAA04818@toad.com>
MIME-Version: 1.0
Content-Type: text/plain


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I just sent the following P.S. to newsday.com

			----------------------

There is another reason to have cellular phones which encrypt only the 
over-the-air portion of a call, besides the fact that we can leave normal 
wiretap access procedures in place and not surrender civilian crypto keys to 
the government.

If I have a cellular phone which encrypts over the air (between the phone 
and the base station) and I call you, while you have a normal wired phone, 
our call is protected by cryptography from interception off the air.

If I use an AT&T Clipper-style cellular phone, as David suggested, and I 
call you on a normal wired phone, we can't encrypt the conversation and it 
is vulnerable to interception.  The protection works *only* if both parties 
have encrypting phones while interoperate.

  - Carl

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+------------------------------------------------------------------+
|Carl M. Ellison       cme@acm.org    http://www.clark.net/pub/cme |
|   PGP 2.6.2: 61 E2 DE 7F CB 9D 79 84  E9 C8 04 8B A6 32 21 A2    |
+-Officer, officer, arrest that man. He's whistling a dirty song.--+