Re: [TLS] New draft: draft-rescorla-tls13-new-flows-01

[Martin Thomson <[e-mail]>]

You could put half of the first round trip in DNS, but that's a fairly
major change to the protocol.  Note however that the ServerParameters
described in the draft is something that could be discovered through
other channels, definitely.  No one is checking where
PredictedParameters came from, just that it is correct.

On 19 February 2014 14:10, Kurt Roeckx <[e-mail]> wrote:
> The only reason I can find in your document is to prevent replay,
> but I currently don't see how this is a problem.

If I had any reason to believe that your first flight included
non-idempotent HTTP requests of interest to me (e.g., transfer $X to
account Y) then replay protection is extremely interesting.

> I'd also like to point out that you might be leaking the site
> you're connecting to via DNS.

There's already been a fair amount of discussion on why some people
are interested in protecting SNI, and that point was addressed there.
I'll point out that confidentiality protection for DNS queries is
being discussed.