I've been experimenting with different forms of protected headers.
I tried modifying the Multilayer PGP/MIME Message with Protected Headers and Legacy Display Part , which has this structure:
A└┬╴multipart/encrypted B ├─╴application/pgp-encrypted C └─╴application/octet-stream ↧ (decrypts to) D └┬╴multipart/signed E ├┬╴multipart/mixed ← Cryptographic Payload F │├─╴text/plain ← Legacy Display Part G │└─╴text/plain H └─╴application/pgp-signature
I'm attaching here two different versions of this structure.
The "normal" variant comes directly from draft -02, following the recommendations there:Its interior (after decryption) is:
The "inline" variant where the original body (part G above) has an additional header of Content-Disposition: inline:Its interior (after decryption) is:
(i'm experimenting with this "inline" variant to try see whether it is an improvement for other systems, see the screenshots project).
However, the "inline" variant actually doesn't render part G at all. Here are the two screenshots:
I'm not sure what it is about the addition of this inner header which makes Outlook appear to swallow the internal part.