Webmailer with encrytion
 

Hey there,
one of my customers is asking for a webmailer that supports digital signing and PGP/GnuPG encryption of mails.
As I saw there is an open ticket for a roundcube plugin on this, but up to now there are only some technical thoughts on how to realize such a plugin.

Do you know a (usable) webmailer that supports those features?

No, unfortunately not (which doesn't mean that there is no such webmailer).

The problem is the private cert.
It needs to be available locally on the client that encrypts the mail. In case of the a webmail app the private cert would be hosted on the server running roundcube.
That is the obstacle they have not overcome. Alternatives are not there yet. I hope the Roundcube Team will make some progress in this direction. There is some chatter in the dev mailinglist. You can subscribe on the roundcube homepage.