I think I've failed to communicate. Yes, the pristine original message will be appropriately MIME-wrapped, with the list decorations becoming separate MIME parts, but the MUA is not expected to do anything except to present the MIME message to the final recipient.
Discussions on the Mailman list say that users hate wrapped messages, because in most MUAs they look really ugly.
Apart from the addition of tags, there isn't much change for DKIM. What changes is the algorithm used by DMARC in the special case where there exists a From-aligned but invalid signature and a Sender-aligned valid signature specifying the tf= tag and (if there's a consensus) an stf= tag.
I still don't see what the advantage is compared to a single message digest which requires no changes to DKIM, no changes to DMARC, and has already been implemented in a widely used list manager. The only downside is that it looks awful in most MUAs so users hate it, which I expect would also apply to your proposal.
R's, John _______________________________________________ dmarc mailing list [email protected] https://www.ietf.org/mailman/listinfo/dmarc
