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.