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Re: [TLS] FNV versus SHA-1 in cached info

Nicolas Williams <Nicolas.Williams@oracle.com> Fri, 07 May 2010 17:29 UTC

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Date: Fri, 07 May 2010 12:28:52 -0500
From: Nicolas Williams <Nicolas.Williams@oracle.com>
To: "Blumenthal, Uri - 0668 - MITLL" <uri@ll.mit.edu>
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Cc: Simon Josefsson <simon@josefsson.org>, "tls@ietf.org" <tls@ietf.org>
Subject: Re: [TLS] FNV versus SHA-1 in cached info
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On Fri, May 07, 2010 at 01:10:40PM -0400, Blumenthal, Uri - 0668 - MITLL wrote:
> For cryptographic purposes agility is critical, and it's obvious.
> 
> For non-cryptographic purposes - who cares. Let the implementers figure what
> works best and "codify" it. If it's SHA - fine. If it's FNV - fine. If it's
> MD4 - fine. No sense avoiding cryptographically broken algorithms for
> non-cryptographic use.

I agree, but it's important to have a rationale for this position.  I
stated one.  Simon and others have stated rationales for the opposite
position (that we should not use MD5 nor SHA-1 even when cryptographic
properties are not required).

It'd be nice if we didn't have to revisit this every time someone needs
a non-cryptographic hash function in an Internet protocol.

Nico
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