> over the web So this confuses a few things. Technically you are right in that TLS applies to the transport layer (layer 4) while both web and email are appli

> over the web So this confuses a few things. Technically you are right in that TLS applies to the transport layer (layer 4) while both web and email are application layer (layer 7), but then the question is how to apply it for email in practice that differs from manual key exchange? Web mail uses web (port 80 or 443) to communicate to a web server email application where the email is blasted out as regular email (most likely as SMTP over port 25). Since the first leg is regular web traffic regular web rules apply, but only to that first leg. Applications like Outlook and Thunderbird are not webmail and do not use web traffic to send/receive email.