hide or rename PGP/MIME signature "attachment"

[LeSpocky]

Without encryption plugin Roundcube shows a PGP/MIME signature as attachment. This is questionable from a technical point of view and confusing for users knowing nothing about encryption or working a lot with attachments.

Technically PGP/MIME sets the Content-Type: of a mail to multipart/signed. Unsigned mails with attachment usually have multipart/mixed set. Further: the content type of the signature itself is application/pgp-signature. So it should be easy to detect this. As far as the attachment symbol in the right most column of the mail list is concerned this already seems to be the case, so when looking for mails with attachment you won't find mails which are just signed.

However in mail view the signature is shown as attachment without type and the filename set in the mail which is signature.asc in many cases. With the above knowledge in mind this could be shown without the irrelevant file name but some descriptive name like »PGP signature« instead, minimizing confusion on user side.

[LeSpocky]

screenshot of PGP/MIME sigend mail

[LeSpocky]

Mails signed with mutt and PGP/MIME are put together a little different, but the problem ist similar. See a signature (with MIME boundaries before and after):

--2oS5YaxWCcQjTEyO
Content-Type: application/pgp-signature
Content-Disposition: inline

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.10 (GNU/Linux)

iEYEABECAAYFAlAW+7sACgkQj7p3RMyHENCCFQCbBF+IvqjUxXCcPD9P4SukbdOd
zbYAnjoQxbhNnN75nVSU2oyhJ5WWzn6J
=N/3g
-----END PGP SIGNATURE-----

--2oS5YaxWCcQjTEyO--

Content type is also application/pgp-signature. This is shown like an attachment with the name "Part 2" instead of naming it "PGP/MIME signature".

[alec]

With commit 830fd2ecbb67c395617e1cc38f343d12af0a2861 signatures are displayed as "Digital Signature". Would be nice to have a better icon for such attachments in Larry skin.

[thomasb]

Icon added in commit [11d7e6c825890]