Re: [saag] Revision of "Attacks on Cryptographic Hashes in Internet Protocols"

Paul Hoffman <paul.hoffman@vpnc.org> Wed, 14 November 2012 22:33 UTC

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From: Paul Hoffman <paul.hoffman@vpnc.org>
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Date: Wed, 14 Nov 2012 14:33:43 -0800
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To: Andrey Jivsov <openpgp@brainhub.org>
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Subject: Re: [saag] Revision of "Attacks on Cryptographic Hashes in Internet Protocols"
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On Nov 14, 2012, at 1:40 PM, Andrey Jivsov <openpgp@brainhub.org> wrote:

> SHA-2 is well-supported today, but there are no solid reasons why SHA-3 will not be supported equally well in the future.

In that future, we can re-look at support for it in IETF protocols. For now, algorithm agility might be sufficient.

> Let's say there is a protocols that is hardwired to SHA1 or MD5. Are we telling people thinking about its improvement to go with the SHA-2?

Yes.

> What about newly designed protocols?

The same.

> If you are a maintainer, what would you prefer: worry about explaining to others that "my SHA-2 use doesn't depend on collision resistance and is not vulnerable to extension attacks", v.s. I "use SHA-3".

Nowhere did we say that you should not use SHA-3. In fact, we said the opposite. We said there was no need to push that.

> I suggest that the document at least softens the statements on SHA-2 v.s. SHA-3. Ideally, I would like to see a path on which we move to the universally supported SHA-3 and, hopefully, the hardware manufacturers are comfortable to jump in.

That's one view; we took a different one. So far, we have had good support in the IETF community for our view, but at some point that might change.

--Paul Hoffman