Further improving digital certificate security
This compromise was detected by Google because they have hard-coded "certificate pins" in Chrome which specify which CAs the browser should expect to see when connecting to Google.This type of "pinning" is the only technique that we know of which has actually detected a CA-assisted MITM attack in the wild (a few times now).  So it works really well, but only if you're running Chrome, and only if you're connecting to Google (or the few other pinned sites hardcoded in Chrome).It doesn't scale well because not every website can (or is willing to) hardcode their CA information in browser binaries, the pinned information has to expire at some point (otherwise you can never change your CA), sites are still vulnerable to their own CAs, and it only works in browsers which are willing to maintain this hardcoded list of pins in their client binaries.Trevor Perrin and I developed a dynamic certificate pinning solution called TACK (http://tack.io) that is designed to address all of those issues.  It's a fully specified TLS extension; all we need are browsers to support it.If you're interested in whats been going on with the CA system, "SSL And The Future Of Authenticity" is a Defcon talk where I discuss some of the problems with CAs, and even interview the original SSL protocol author about them: https://www.youtube.com/watch?v=8N4sb-SEpcg