Hiya, On 23/10/2019 22:45, Christopher Wood wrote: > On Wed, Oct 23, 2019, at 2:12 PM, Stephen Farrell wrote: >> >> >> On 23/10/2019 17:13, Ben Schwartz wrote: >>> On the topic of radical suggestions, here's another one: >>> https://github.com/tlswg/draft-ietf-tls-esni/pull/186 >> >> How about a variant like this (which is maybe close to your most >> recent email, not quite sure): >> >> Names < N octets: pad those to N. >> >> Names >= N octets: hash those and pad to N. >> >> With N ~=64 I think that'd be ok, assuming we do some checking that >> N covers a sufficient percentage of names in real use. > > For this and other proposals, it seems there's different assumptions > being made. I'd prefer to not make any change absent further analysis > with clear guidance pointing towards a safe policy. Absent that, the > safest approach (260B) seems prudent.
Fixed at 260 octets is better that what we have and safest, yes. I think we could do better though, but agree that proposals for that need analysis. >> I think the WG could easily make the case that if some web site >> really does need/want to hide in the crowd, they just better not >> try do that with a gigantic DNS name. > > Why would such a site use ESNI at all? My hope is browsers and sites might all just use ESNI eventually. But I think we are ok to consider that over-sized names may face some implementation obstacles. I suspect, but don't know, that hash based approaches are liable to break server-internal APIs in various ways. But that might be ok, if the numbers are small enough. Cheers, S. PS: Despite raising the above variant, I still think "behave the same as DNS query padding as far as possible" is still the right approach to try next. Given DNS query padding works, that is I think, as safe as a fixed use of 260 octets. > > Best, Chris > > _______________________________________________ TLS mailing list > [email protected] https://www.ietf.org/mailman/listinfo/tls >
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