Re: [TLS] What does it mean to not include 0-RTT message in the handshake hash?

Eric Rescorla <ekr@rtfm.com> Tue, 22 December 2015 02:41 UTC

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From: Eric Rescorla <ekr@rtfm.com>
Date: Mon, 21 Dec 2015 18:40:39 -0800
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To: Dave Garrett <davemgarrett@gmail.com>
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Subject: Re: [TLS] What does it mean to not include 0-RTT message in the handshake hash?
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On Mon, Dec 21, 2015 at 6:33 PM, Dave Garrett <davemgarrett@gmail.com>
wrote:

> On Monday, December 21, 2015 09:25:44 pm Christian Huitema wrote:
> > > I was just going over this text today and realized it's kind of
> confusing
> > > (and the whole "handshake_hash" abstraction is starting to be less
> useful
> > > in light of the PR#316 reframing of the authentication block).
> >
> > Yes, the "handshake hash" is indeed confusing. Specifying something like
> "all messages up to <some point>" is simple enough. But there are several
> such points, used at different stages. Server Hello, Server certificate
> verify, Server Finished, Client certificate verify, Client finished.. It
> would be a bit more clear to give each of them its own name.
>
> Along this same line, I'd suggest getting rid of "session_hash", at least
> as-is. Instead, just use "handshake_hash" for everything and specify what's
> included at each use. "Session hash" is just another term that has to be
> referenced, when it's just the final state of the handshake hash.


I tend to agree



> The term doesn't really add anything unless every separate stage of the
> handshake hash was named separately (in which case, "handshake_hash_*"
> naming might be more clear)


Yeah, that might work.

I'm putting the final touches on draft-11 and will see what I can do to
clarify this.

Thanks
-Ekr


>
>
> Dave
>