From: cmca@alpha.c2.org (Chris McAuliffe)
Date: Thu, 14 Mar 1996 05:53:56 +0800
To: perry@piermont.com
Subject: Re: Remailer passphrases
In-Reply-To: <199603121951.OAA02237@jekyll.piermont.com>
Message-ID: <199603122332.PAA04146@eternity.c2.org>
MIME-Version: 1.0
Content-Type: text/plain


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[To: perry@piermont.com]
[cc: cypherpunks@toad.com]
[Subject: Re: Remailer passphrases ]
[In-reply-to: Your message of Tue, 12 Mar 96 14:51:47 EST.]
             <199603121951.OAA02237@jekyll.piermont.com> 

"Perry E. Metzger" <perry@piermont.com> enscribed:
>Bill Frantz writes:
>> One of the reasons classical (government) crypto users change keys
>> frequently is to minimize the amount of data compromised by a broken key. 
>> We keep hearing about NSA decrypting 20 year old cyphertext and showing
>> more of the workings of the atomic spy rings operating in the 40s and 50s. 
>> If an opponent can rubber hose the key, her job is easy.  If she has to
>> perform cryptoanalysis, it is much harder.  Remailers should regularly
>> change their keys to avoid compromising previously recorded traffic.  (They
>> can have a long lived key for signing their traffic keys.)

>Signed Diffie-Hellman key exchanges have the property known as
>"Perfect Forward Secrecy". Even if the opponent gets your public keys
>it still will not decrypt any traffic for him at all -- it just lets
>him pretend to be you. Thats one reason why protocols like Photuris
>and Oakley use the technique.

True, but when the problem at hand is sending mail to a remailer, the
technique is of little or no value, since there is no initial exchange,
right? So this is a misleading argument. At least it is related to
cryptography and The Cypherpunk Agenda(tm)!

Chris McAuliffe <cmca@alpha.c2.org> (No, not that one.)

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