PGP encryption is one of the most frequently requested features for Roundcube and for good reasons more and more people start caring about end-to-end encryption in their everyday communication. But unfortunately webmail applications currently can’t fully participate in this game and doing PGP encryption right in web-based applications isn’t a simple task. Although there are ways and even some basic implementations, all of them have their pros and cons. And yet the ultimate solution is still missing.
Browser extensions to the rescue
In our opinion, the way to go is with a browser extension to do the important work and guard the keys. A crucial point is to keep the encryption component under the user’s full control which in the browser and http world can only be provided with a native browser plugin. And the good news is, there are working extensions available today. The most prominent one probably is Mailvelope which detects encrypted message bodies in various webmail applications and also hooks into the message composition to send signed and encrypted email messages with your favorite webmail app. Plus another very promising tool for end-to-end encryption is coming our way: p≡p. A browser extension is at least planned in the longer term. And even Google just started their own project with the recently announced end-to-end Chrome extension.
That’s a good start indeed. However, the encryption capabilities of those extensions only cover the message body but leave out attachments or even pgp/mime messages. Mostly because there extension has limited knowledge about webmail app and there’s no interaction between the web app and the extension. On the other side, the webmail app isn’t aware of the encryption features available in the user’s browser and therefore suppresses certain parts of a message like signatures. A direct interaction between the webmail and the encryption extension could help adding the missing pieces like encrypted attachment upload and message signing. All we need to do is to introduce the two components to each others.