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Re: [TLS] 0-RTT, server Application Data, and client Finished

Ilari Liusvaara <ilariliusvaara@welho.com> Wed, 27 January 2016 19:44 UTC

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Date: Wed, 27 Jan 2016 21:44:17 +0200
From: Ilari Liusvaara <ilariliusvaara@welho.com>
To: David Benjamin <davidben@chromium.org>
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Subject: Re: [TLS] 0-RTT, server Application Data, and client Finished
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On Wed, Jan 27, 2016 at 07:28:47PM +0000, David Benjamin wrote:
> On Tue, Jan 26, 2016 at 10:32 PM Martin Thomson <martin.thomson@gmail.com>
> wrote:
> >
> > I get your point, but I don't see that as a simplification.  In my
> > mind, post-handshake client authentication doesn't happen.  Or, I
> > don't see it being commonplace.
> 
> But the only cases where this flow is useful (server sends non-zero
> unauthenticated bytes at t=0.5 before the authenticated bytes at t=1.5) has
> all the same pitfalls of mid-stream auth (specifically that the stream's
> authentication switches partway through), so I don't see what avoiding
> mid-stream auth is supposed to gain.

I don't think the two situations have the same problems:
- "Server 0-RTT" has _recipient_ identity change.
- "Dynamic reauth" has _sender_ identity change.

You have more concrete examples of things going wrong with "server
0-RTT"? Because I have major problems coming up with troublesome
cases.


-Ilari

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