[niftich]

The draft work which proposes what amounts to an ALPN protocol-name echo as an implicit signal to some heretofore unspecified compliance with ACME workarounds is a mistake. Even the suggestion to "scan alexa's top sites" to see if accidentally-clashing behavior is observed in the wild is naive at best, mind-numbingly misguided at worst.

Like you suggest, it's important to be explicit, and if they wish to lean on yet another protocol, now is an opportunity to enumerate the exact behaviors they want. It's good that this work has begun, but I hope it won't be rushed.

[mdhardeman]

Agree 100%. I actually just joined the ACME mailing list to comment along those lines.

I hope that wasn't against protocol.

It will do favor to no-one to rush this. It's broken bad enough that it needs a fresh cycle of iteration and testing.

The Alexa scan idea is weak. Of course no one advertises "acme" as an ALPN name now. There's no incentive to today. If the proposal Mr. Rudenberg made were accepted, there'd be plenty of incentive for these same broken shared hosts to advertise an ALPN identifier of "acme". It just wouldn't be coupled with any incentive to fix the other issues.

On that topic, the proposed edit does not even attempt to define what circumstances/facts/assertions a presenter of the ALPN "acme" is hypothetically promising. No attempt is even made to extract a gentleman's agreement that a shared host vulnerable to the attacks which have been described would not advertise this ALPN. Of course, there's no real point to trying to extract that. The shared host would have no incentive to hold up their end of that promise.

But if this proposal as suggested moved forward without further revision, there would be incentive to make your TLS endpoint with "acme" tomorrow, whether or not your infrastructure is secure against the actual attack vectors that have effectively disqualified TLS-SNI-01 and TLS-SNI-02 at the present.