On Fri, Apr 03, 2020 at 02:10:22PM -0400, Wietse Venema wrote:
> >
> > As an incoming MTA, after Postfix receive messages, which part takes the
> > duty of saving messages to disk?
>
> The cleanup(8) daemon writes incoming mail to a queue file.
>
> There are about a dozen other daemons that read from a queue file.
Is the OP looking to encrypt queue files, or to encrypt message bodies
using recipient public keys?
For the latter, there are various systems that make it possible to
encrypt email in transit, so that by the time it is delivered to a
mailbox (and perhaps somewhat earlier) the content can only be read by
the recipient.
Suitably capable disks support encryption via keys held in the disk
controller, so that if the disk is ever separated from the machine, its
content should be unreadable.
--
Viktor.
