On Sep 21, 6:18pm, Jeff Thompson wrote:
Subject: S/MIME "security hole" fix
Concerning the the "gaping security hole" of using S/MIME's
multipart/alternative approach with a remote message validation
server:
Since the remote validation server is S/MIME-aware (it is checking the
signature), then it can also check if the message it is verifying is
multipart/alternative. If it is, then it can simply confirm that the
data in the "clear" part is the same as the data inside the PKCS
part.
This would be a good thing to suggest in the S/MIME spec, thus closing
the "security hole."
Jeff,
I'm not sure this is as easy as it sounds. If the clear text part is
encoded to be exactly the same as the signed part then yes it's pretty
easy but then the goal of having easy to read clear text is missed by a
mile. When the clear text part is treated as normal RFC822 messages
then plenty can (legally) happen to the text during transmission
that will make an exact comparison (which is what is required) impossible.
Yet Another Steve
--
Steven Miller is miller(_at_)wingra(_dot_)com