john:
> We need to ensure that emails sent by some of our users are encrypted
> (medical records, reports, etc) before they are sent.
>
> We only accept out going mail from our local users by submission (port
> 587).
>
> I realize that this is really the job of the MUA, but I would like to
> check that emails are in fact encrypted before being sent. If an
> unencrypted email is encountered transmission would be denied with a
> suitable message/code. One other thing that we might also need to do is
> to move the supplied subject into the body of the message and substitute
> a generic heading, this to prevent the patient name showing up in plain
> text.
"Enforcing encryption" and "hiding the subject in the body" are not
built-in features of Postfix (or other conventional MTA). It is what
one would expect to find in specialized MIME or PGP gateways. There
are a few listed at the www.postfix.org site, but the list isn't
updated frequently.
Wietse