[TLS] Collisions (Re: Nico's suggestions - Re: Consensus Call: FNV vs SHA1)

Nicolas Williams <Nicolas.Williams@oracle.com> Mon, 10 May 2010 21:41 UTC

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Date: Mon, 10 May 2010 16:39:25 -0500
From: Nicolas Williams <Nicolas.Williams@oracle.com>
To: Stefan Santesson <stefan@aaa-sec.com>
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Cc: Paul Hoffman <paul.hoffman@vpnc.org>, tls@ietf.org
Subject: [TLS] Collisions (Re: Nico's suggestions - Re: Consensus Call: FNV vs SHA1)
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On Mon, May 10, 2010 at 11:32:24PM +0200, Stefan Santesson wrote:
> I'm OK with everything Nico suggests with respect to FNV (If Joe is fine
> with an informational reference to a web page)

There are many examples of informational references to non-IETF,
non-standard documents.  For example, BCP0106 (remember the RNG thread?)
has an informational reference to "Turbid" in the form of a URL that is
clearly not stable in the same way that an RFC number is.  If you look
around you'll find many information references in RFC to I-Ds (usually
labeled "work in progress").

> On the last question I think the correct answer is: Yes it is possible to do
> a variant of the protocol without a hash function but it does not make the
> protocol any better. Rather it make it worse. Both in terms of functionality
> and complexity.

That's just a statement without an argument; I'm unconvinced.  Convince
us.  If you can show that collisions don't result in failure to complete
a TLS handshake successfully then all will be fine, so start there.
Else I think you should explain how a collision-free protocol would be
worse than the current proposal, then we could weigh the two approaches.

Nico
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