Re: Question about signing attachments separately

Karen missed Mark's point. If you have a MIME entity such as a
multipart/mixed,
you have the option of treating that as a single entity and signing it, or
signing each sub-entity. I believe the current S/MIME spec is silent on this
choice, but I suspect that some implementations may not handle signatures on
non-nested subentities very well.

--Paul Hoffman, Director
--Internet Mail Consortium