I don't think (and wouldn't hope) this would be a flag-day thing where we stop using CA trust completely all at once and only use DANE afterward. DANE would become an option, disabled or secondary by default, that users could choose to use as a fallback if CA-based TLS validation fails. Eventually as adoption increased and the critical paths got cleaned up, DANE could become the default primary, with a fallback to CA trust if there's no valid response to a TLSA record request. Eventually as CA trust fell completely out of favor for most uses, it wouldn't be necessary for many clients to support it at all.

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tptacek 2 hours ago | parent [-]

See, this doesn't work either. One of the core jobs you have designing a secure transport is avoiding downgrade attacks, and the construction you just outlined is not only downgradable, it's explicitly downgradable, as a feature. That's not going to happen.

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kensey 2 hours ago | parent [-]

So the answer is just to use only the weaker option forever?

	▲	tptacek 2 hours ago \| parent [-]
		No? There's a very specific technical problem that makes DNSSEC hard to deploy effectively. You can't just define it away. You have to pursue solutions that solve that problem. There's a whole huge solution space to draw from, but people are so path-dependent and so predisposed to like the IETF that DNSSEC is just the only discussion we seem to be able to have. Fortunately, the WebPKI has been ratcheting (slowly) up security over the last 15 years, so when nothing else happens, which is what I predict, at least we'll be in a better place a decade from now.