Re: [exim] Storing messages in Maildir format with symmetric…

On 23/11/2022 00:16, Dengler, Gabriel via Exim-users wrote:
> I want to store the incoming e-mails using the Maildir file format encrypted by using some symmetric encryption using the user's password

It seems like a generally valuable concept - but I'd think that assymetric encryption
of the data-at-rest is more appropriate than symmetric. The MDA (exim, here, receiving
a message and delivering to file) shou be able to encrypt for the destination user
but NOT decrypt. So it should have access to a public key and not a private key
for the destination mailbox - and this is entirely separate from notions of
SMTP authentication.

Where to implement it in the code? Probably pretty late in the appendfile
transport; about where it's doing actual writes to the file fd - and using
a public key supplied via a transport option (which the config pulls
from a database lookup using the username, or localpart, or whatever)
and perhaps another giving the cipher scheme.
--
Cheers,
Jeremy