Operators who host infrastructure can and should be monitoring issuance in CT logs for domains they operate, which will allow them to identify and react to any unexpected issuance for those domains.
> If the installed version of Chrome has not applied security updates and has been unable to obtain an updated CT log list from the Component Updater for 70 days or more, then CT enforcement will be disabled.
That means a global adversary need merely block the update channel to targeted devices and wait. How will a Smart TV behave?
> Certificate transparency is cool, but it's not clear it really works for many classes of devices
Smart TVs aren't some gotcha I'm throwing in at the end. It's literally the first thing I said about CT. CT works ok for mobile phones, laptops, and other devices where you can make certain assumptions about multiple networks and frequent updates. If you want a technology that doesn't require these assumptions, you want DNSSec.
I want a version of Web PKI strong enough that I can turn off my tablet for a year, turn it back on in a coffee shop, apply automatic updates, and not have my web traffic monitored, even if I'm gay and the coffee shop is in Saudi Arabia.
From what I can see, DNSSec+CAA+.com+US CA+US hosting for the Android update server does the trick. No version of CT does.
It's late and I maybe haven't been super constructive here, but I think when you try to write out the actual assumptions behind CT as the whole solution, you realize you've got something that mostly works assuming assuming assuming - and worse, we'll never do any better, because those assumptions are fundamental technical limits. DNSSec may be ugly but at least its problems (like validators failing open) are just deployment issues, not fundamental technical issues.
I'm sick and tired of using technologies that provide security or correctness subject to a long list of preconditions and ways for folks to tell me I'm using it wrong. To build secure systems, we need technology that provides correct security without so much asterisks and fine print.