PGP Partitioned
PGP Partitioned is a format optionally used by Symantec in it's Endpoint security solution.
It's not an official standard, it does not have a content type. There is just some mailing thread describing it. (partitioned) PGP Partitioned is basically a word for "PGP/Inline Mail Body and each attachment encrypted / signed separately "
It can usually be identified by a "PGPexch.htm.pgp" Attachment containing the body of the mail as a HTML Page.
Symantec's PGP Desktop can be configured to send PGP/MIME. This should be preferred.
Critique
- PGP Partitioned is not standardized in an RFC.
- It does not properly handle encoding as it uses PGP/Inline.
- Attachments and the Text are encrypted / signed as different PGP Messages.
E.g. for a Signed and Encrypted Message with 10 Attachments a receiving MUA would have to show 10 different decryption and verification states. To do this securely and user friendly is nearly impossible.
An attacker could add or remove attachments to a mail or change the encoding specified in the mail header making this format inherently insecure.