Just off the top of my head, isn't this what pgp (and therefore gpg) do? Excaept I don't know if they can use the verisign cert, but I'd think they would.

And there are perl interfaces to gpg, though I haven't used them.

how about SMIME? smime

You may still have to handle the mechanics of getting the email sent to an SMTP server: SMTP or MIME.

--Bob Niederman, http://bob-n.com