So, one CA to rule then all? There's a scenario (simplified for illustration, but entirely possible) that's normally not a huge risk because there are many CAs, and they are private, for-profit companies that have an economic incentive to protect you and your certificate's ability to assure end users that a conversation's privacy won't be compromised. 1) browser requests site via SSL 2) MITM says, "let's chat - here'…
We will look for ways to mitigate the risk of misissuing for any reason, including because someone tries to coerce us to misissue. One approach to this that's interesting is Certificate Transparency. http://www.certificate-transparency.org/ There's also HPKP, TACK, and DANE, plus the prospect of having more distributed cert scans producing databases of all the publicly visible certs that people are encountering on th…
Only one "root CA" to trust per TLD, and it's free if you own a TLD that supports DNSSEC (most do these days).
Now we just need the DANE check built into the browser without any plugins that require installation.