From: jalicqui@prairienet.org (Jeff Licquia)
Date: Wed, 18 Jan 95 11:42:18 PST
To: cypherpunks@toad.com
Subject: Re: EE Times on PRZ
Message-ID: <9501181942.AA27518@firefly.prairienet.org>
MIME-Version: 1.0
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Strick wrote:
>THUS SPAKE jalicqui@prairienet.org (Jeff Licquia):
># Another quote from the article posted elsewhere said that, "PGP, which is
># based on the Diffie-Hellman public-key technology developed in the 1970s..."
># This is technically true, since all public-key work (including RSA) is based
># to some extent on DH.  It could be, however, that the author is confusing
>
>DH uses "discrete log" as the hard problem, and very straightforward
>mathematics.
>
>RSA uses "factoring" as the hard problem, and a very clever back door.
>
>How do you decide if one is based on the other?

Sorry, I wasn't perfectly clear.  Of course, RSA is not based on
Diffie-Hellman specifically; what I mean is that all public-key work is
based on that general paper, which "invented" public-key cryptography.  I
think this very confusion may be plaguing the writer of the aforementioned
article.

># public-key technology with Diffie-Hellman public-key in particular, which
># (as I understand it) is not particularly secure.
>
>It's still up in the air, isn't it, whether the discrete log or 
>factoring is the harder to crack.   My intuition is they're the
>same hard.

It was my impression that DH had a further weakness not related to the
difficulty of the hard problem.  As my copy of Schneider is at home, I must
defer to ignorance at this point.