[43939] in Cypherpunks
Re: Cypherpunk Certification Authority
daemon@ATHENA.MIT.EDU (Mark Chen)
Sat Nov 25 21:21:36 1995
From: chen@intuit.com (Mark Chen)
To: adam@homeport.org (Adam Shostack)
Date: Sat, 25 Nov 1995 18:27:29 -0800 (PST)
Cc: cypherpunks@toad.com (cypherpunks)
In-Reply-To: <199511252105.QAA08724@homeport.org> from "Adam Shostack" at Nov 25, 95 04:05:28 pm
> | C) Don't settle for less than X.509 ver 3, because this allows the
> | certificate to carry within it a reference to the location of the CRL
> | list. Use that feature.
>
> Does X.509 version 3 fix the problem that Ross Anderson points
> out in his 'Robustness Principles' paper? (Crypto '95 proceedings, or
> ftp.cl.cam.ac.uk/users/rja14/robustness.ps.Z)
I don't believe that it does.
For those who missed it, the problem is that the encryptor in an
encrypt-before-signing protocol is able to use his knowledge of the
factorization of the encryption modulus to compute a discrete log, and
forge another message for which the signature is also valid (after
registering the new exponent).
- Mark -
--
Mark Chen
chen@intuit.com
415/329-6913
finger for PGP public key
D4 99 54 2A 98 B1 48 0C CF 95 A5 B0 6E E0 1E 1D
