Outlook express messes up when it receives gpg-signed mail?

Ben Finney ben@benfinney.id.au
Fri Sep 5 04:53:01 2003

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On 03-Sep-2003, Chris Niekel wrote:
> [sending email to be read with MS Outlook]
> When I sent an unsigned message, the text gets displayed, but when I
> send a signed message, see sees an empty body, with two attachments.

The mail is sent as a MIME "multipart/signed" message, which is a valid
MIME message type.  The message body is "Content-Type: text/plain" and
the signature is "Content-Type: application/pgp-signature".

Every part of this is "Content-Disposition: inline", signalling that the
content, if understood, should be shown inline (not as an attachment).

It's quite valid for an MUA not to understand MIME at all, and show the
whole message, MIME guff and all.  The content is still readable, since
the body is "text/plain".

It's quite valid for a MUA process MIME, but to fail to understand a
Content-Type (such as "application/pgp-signature") and show those parts
as attachments.  This is what commonly occurs with the signature in MUAs
that don't know OpenPGP, and still allows the message body to be read
(since all MIME MUAs understand "text/plain").

What Outlook is doing wrong, then, is failing to display a "text/plain",
"inline"-disposition body.  There's no reason for it to do this; both
those are demonstrably understood by Outlook in other MIME messages.

 \         "If life deals you lemons, why not go kill someone with the |
  `\  lemons (maybe by shoving them down his throat)."  -- Jack Handey |
_o__)                                                                  |
Ben Finney <ben@benfinney.id.au>

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