Hello :-)
I've been working on implementing OpenPGP.js in Roundcube for the past couple of days. It's still an unfinished project in development, but since there's such high demand for the result I ought I'd ask you guys for some early feedback.
For those of you who don't know: OpenPGP.js is a fork of the previous GPG4Browsers. The intent is to port all OpenPGP functionality into JavaScript so that third party software isn't required for PGP activity. It uses HTML5 web storage and standard PKI keyrings (private keys excluded).
So far the plugin, rc_openpgpjs, has a "temporary"(?) user interface for key management and selection. Its consciously using a pretty rough UI at the moment because the new design for Roundcube is just around the corner, but just not finished enough yet to start working on. Also the Enigma plugin interface looked in trouble in Larry.
Speaking of Enigma: I'm sure someone will ask why I extend that instead. With all due respect to its authors and fans, Enigma has been stuck in development for 2 years, and PGP support has been planned for Roundcube for 6 years. I'm not sure whether Enigma is really relevant or not. Also I can not support a plugin that implements encryption as a server side solution. The main goal of encryption is to ensure that the data can not be accessed by unauthorized people. I believe that people hosting other people's mail should be treated as unauthorized, and giving private keys away to somebody else really fights against the entire purpose. And then arises the exact same problem that Hushmail users are experiencing: http://www.wired.com/threatlevel/2007/11/encrypted-e-mai/
Even though most Roundcube users probably host their own email I'm quite sure most people don't have problems with a client sided solution instead. That said, I'm not opposed to the Enigma plugin in any way. I was only too lazy to bother learning its structure and layout, which turned out to not be entirely supported by the Larry design. I wouldn't mind a merge later on.
Anyhow! Check it out, and tell me what you think. I strongly welcome UI recommendations, patches or any other tip about how I should progress. It's still in early development, but most of the key management features are implemented and so is the decryption of emails. Nothing about the UI is finished.
https://github.com/qnrq/rc_openpgpjs
Cheers!
/Nik