This has been a long time coming — properly encrypted Gmail — but it’s very welcome. Here’s the relevant extract from the Google security blog:
Today, we’re adding to that list the alpha version of a new tool. It’s called End-to-End and it’s a Chrome extension intended for users who need additional security beyond what we already provide.
“End-to-end” encryption means data leaving your browser will be encrypted until the message’s intended recipient decrypts it, and that similarly encrypted messages sent to you will remain that way until you decrypt them in your browser.
While end-to-end encryption tools like PGP and GnuPG have been around for a long time, they require a great deal of technical know-how and manual effort to use. To help make this kind of encryption a bit easier, we’re releasing code for a new Chrome extension that uses OpenPGP, an open standard supported by many existing encryption tools.
However, you won’t find the End-to-End extension in the Chrome Web Store quite yet; we’re just sharing the code today so that the community can test and evaluate it, helping us make sure that it’s as secure as it needs to be before people start relying on it. (And we mean it: our Vulnerability Reward Program offers financial awards for finding security bugs in Google code, including End-to-End.)
Once we feel that the extension is ready for primetime, we’ll make it available in the Chrome Web Store, and anyone will be able to use it to send and receive end-to-end encrypted emails through their existing web-based email provider.
We recognize that this sort of encryption will probably only be used for very sensitive messages or by those who need added protection. But we hope that the End-to-End extension will make it quicker and easier for people to get that extra layer of security should they need it.