Mailvelope - PGP for webmails - gets safer with latest update and security audit

I will add that the author addressed most of the complains - you can write, encrypt and decrypt mails in a window completely separate from the window, that appears with a click in the webmail window.

It is protected from clickjacking by secret token that the user can set up in settings that will appear in the new window. See http://www.mailvelope.com/help#security