S/MIME capable mail application for OS X

Is there a mail application for Mac OS X with S/MIME support and keychain integration other than Apple's Mail.app?

Thunderbird has S/MIME but no keychain access (please correct me).
MailMate has keychain access but no S/MIME.
Postbox, although it claims to has good system integration, it does not as keychain access, but mozillastyle cryptowallet.
Sparrow does not have S/MIME.

Max Ried

Posted 2011-06-09T10:00:02.477

Reputation: 1 521

1Just curious: what is it you don't like about Mail's signing/encryption? (And if you're using Time Machine then you might want to use a mail program that uses small files to store the messages, rather than one huge file to store multiple messages.) – Arjan – 2011-06-10T16:57:15.500

Answers

Outlook 2011 is the only application of which I am aware that uses Apple's keychain to store digital certificates for S/MIME.

Art Taylor

Posted 2011-06-09T10:00:02.477

Reputation: 198

Yeah, beside Mail.app. Is implementing S/MIME that complicated? – Max Ried – 2011-06-10T16:59:57.070

No. In fact, if you are willing to pay, or are looking for an enterprise solution, Symantec (who I believe acquired both Verisign and PGP) has a proxy-like solution for transparent S/MIME. Of course, it doesn't use the OS X keychain. I suspect the easiest approach would be to take one of the open-source MUAs you do like and has S/MIME support and hijack its keystore to use Keychain. Out of curiosity, why is Mail.app inadequate? – Art Taylor – 2011-06-10T19:18:28.567

1E.g. Mail.app has no mailing list support, no custom mail header filtering. I'm missing some advanced features. It's OK as a basic mail client for the stereotypic apple customership. – Max Ried – 2011-06-10T20:19:32.897

Makes sense. I go a little nuts trying to use it without Mail Act-On and MailTags, along with a few other plugins. I use server-side IMAP folder filtering for mailing lists, but that's an annoying manual process. – Art Taylor – 2011-06-10T20:58:36.433

Have a look at this -- I believe it takes care of what you're asking about, though it's actually an add-on to Mail.app, as opposed to a stand-alone mail client with built-in encryption functionality. It was a dead project about a year ago, and Snow Leopard support wasn't available but some folks picked it up and turned it into a friendly install package. My testing shows it to be pretty stable.

http://www.gpgtools.org/installer/index.html

You can also install individual components from the suite if you want to. Specifically I installed gpgmail (see link below), because I already had a gpg keychain manager in place. But if I were starting from ground zero, I'd probably go with the overall gpgtools installer.

http://www.gpgtools.org/gpgmail/

jon

Posted 2011-06-09T10:00:02.477

Reputation: 26

2Excuse me, but I'm looking for S/MIME. – Max Ried – 2011-06-10T16:44:19.763

The GnuPG project actually supports S/MIME since version 2.0. http://www.gnupg.org/ Maybe it's still not what you're looking for, but wanted to point that out in case it's helpful. Were you referring specifically to integration with Apple's keychain application, or just some type of keychain manager (as Art seems to be alluding to)?

– jon – 2011-06-10T18:23:46.243

Apple's keychain. It's the most convenient way on OS X. – Max Ried – 2011-06-10T18:49:07.393