Re: [Cfrg] RGLC on draft-irtf-cfrg-kangarootwelve-01

Stephen Farrell <stephen.farrell@cs.tcd.ie> Sun, 16 February 2020 14:53 UTC

Return-Path: <stephen.farrell@cs.tcd.ie>
X-Original-To: cfrg@ietfa.amsl.com
Delivered-To: cfrg@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 1ECD3120052 for <cfrg@ietfa.amsl.com>; Sun, 16 Feb 2020 06:53:30 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -4.299
X-Spam-Level:
X-Spam-Status: No, score=-4.299 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (1024-bit key) header.d=cs.tcd.ie
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id sSE8OVIaTT6o for <cfrg@ietfa.amsl.com>; Sun, 16 Feb 2020 06:53:27 -0800 (PST)
Received: from mercury.scss.tcd.ie (mercury.scss.tcd.ie [134.226.56.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 94E1E120020 for <cfrg@irtf.org>; Sun, 16 Feb 2020 06:53:27 -0800 (PST)
Received: from localhost (localhost [127.0.0.1]) by mercury.scss.tcd.ie (Postfix) with ESMTP id 0D21EBE2E; Sun, 16 Feb 2020 14:53:25 +0000 (GMT)
X-Virus-Scanned: Debian amavisd-new at scss.tcd.ie
Received: from mercury.scss.tcd.ie ([127.0.0.1]) by localhost (mercury.scss.tcd.ie [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id WEHtcPwjurOo; Sun, 16 Feb 2020 14:53:20 +0000 (GMT)
Received: from [10.244.2.119] (95-45-153-252-dynamic.agg2.phb.bdt-fng.eircom.net [95.45.153.252]) by mercury.scss.tcd.ie (Postfix) with ESMTPSA id 773B4BE24; Sun, 16 Feb 2020 14:53:20 +0000 (GMT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=cs.tcd.ie; s=mail; t=1581864800; bh=dz/3ON0dnDuV/TjZ+yv8Y5zjEk79LFAQULAyiUJRVO0=; h=To:References:From:Subject:Date:In-Reply-To:From; b=t/gA5ZnmOuH0iveUG++FHhqBEUONYrEmuaG10iI1KnACMqqmKbcvoMNkE0NJ8rYCk W4CvvDj+xzYWQGeB0APqOxp0I0hPZtsfkru7XhTU4E5SDf566pmdYkqO7iXdxJ8afH q40QPjCOxwr6vmEH18Nq6PgsWEZXnA4jRBJxWF5I=
To: Alexey Melnikov <alexey.melnikov@isode.com>, "cfrg@irtf.org" <cfrg@irtf.org>
References: <DF952AED-7578-47B8-B42F-F6A18A927C31@isode.com>
From: Stephen Farrell <stephen.farrell@cs.tcd.ie>
Autocrypt: addr=stephen.farrell@cs.tcd.ie; prefer-encrypt=mutual; keydata= mQINBFo9UDIBEADUH4ZPcUnX5WWRWO4kEkHea5Y5eEvZjSwe/YA+G0nrTuOU9nemCP5PMvmh 5Cg8gBTyWyN4Z2+O25p9Tja5zUb+vPMWYvOtokRrp46yhFZOmiS5b6kTq0IqYzsEv5HI58S+ QtaFq978CRa4xH9Gi9u4yzUmT03QNIGDXE37honcAM4MOEtEgvw4fVhVWJuyy3w//0F2tzKr EMjmL5VGuD/Q9+G/7abuXiYNNd9ZFjv4625AUWwy+pAh4EKzS1FE7BOZp9daMu9MUQmDqtZU bUv0Q+DnQAB/4tNncejJPz0p2z3MWCp5iSwHiQvytYgatMp34a50l6CWqa13n6vY8VcPlIqO Vz+7L+WiVfxLbeVqBwV+4uL9to9zLF9IyUvl94lCxpscR2kgRgpM6A5LylRDkR6E0oudFnJg b097ZaNyuY1ETghVB5Uir1GCYChs8NUNumTHXiOkuzk+Gs4DAHx/a78YxBolKHi+esLH8r2k 4LyM2lp5FmBKjG7cGcpBGmWavACYEa7rwAadg4uBx9SHMV5i33vDXQUZcmW0vslQ2Is02NMK 7uB7E7HlVE1IM1zNkVTYYGkKreU8DVQu8qNOtPVE/CdaCJ/pbXoYeHz2B1Nvbl9tlyWxn5Xi HzFPJleXc0ksb9SkJokAfwTSZzTxeQPER8la5lsEEPbU/cDTcwARAQABtDJTdGVwaGVuIEZh cnJlbGwgKDIwMTcpIDxzdGVwaGVuLmZhcnJlbGxAY3MudGNkLmllPokCQAQTAQgAKgIbAwUJ CZQmAAULCQgHAgYVCAkKCwIEFgIDAQIeAQIXgAUCWj6jdwIZAQAKCRBasvrxexcr6o7QD/9m x9DPJetmW794RXmNTrbTJ44zc/tJbcLdRBh0KBn9OW/EaAqjDmgNJeCMyJTKr1ywaps8HGUN hLEVkc14NUpgi4/Zkrbi3DmTp25OHj6wXBS5qVMyVynTMEIjOfeFFyxG+48od+Xn7qg6LT7G rHeNf+z/r0v9+8eZ1Ip63kshQDGhhpmRMKu4Ws9ZvTW2ACXkkTFaSGYJj3yIP4R6IgwBYGMz DXFX6nS4LA1s3pcPNxOgrvCyb60AiJZTLcOk/rRrpZtXB1XQc23ZZmrlTkl2HaThL6w3YKdi Ti1NbuMeOxZqtXcUshII45sANm4HuWNTiRh93Bn5bN6ddjgsaXEZBKUBuUaPBl7gQiQJcAlS 3MmGgVS4ZoX8+VaPGpXdQVFyBMRFlOKOC5XJESt7wY0RE2C8PFm+5eywSO/P1fkl9whkMgml 3OEuIQiP2ehRt/HVLMHkoM9CPQ7t6UwdrXrvX+vBZykav8x9U9M6KTgfsXytxUl6Vx5lPMLi 2/Jrsz6Mzh/IVZa3xjhq1OLFSI/tT2ji4FkJDQbO+yYUDhcuqfakDmtWLMxecZsY6O58A/95 8Qni6Xeq+Nh7zJ7wNcQOMoDGj+24di2TX1cKLzdDMWFaWzlNP5dB5VMwS9Wqj1Z6TzKjGjru q8soqohwb2CK9B3wzFg0Bs1iBI+2RuFnxLkCDQRaPVAyARAA+g3R0HzGr/Dl34Y07XqGqzq5 SU0nXIu9u8Ynsxj7gR5qb3HgUWYEWrHW2jHOByXnvkffucf5yzwrsvw8Q8iI8CFHiTYHPpey 4yPVn6R0w/FOMcY70eTIu/k6EEFDlDbs09DtKcrsT9bmN0XoRxITlXwWTufYqUnmS+YkAuk+ TLCtUin7OdaS2uU6Ata3PLQSeM2ZsUQMmYmHPwB9rmf+q2I005AJ9Q1SPQ2KNg/8xOGxo13S VuaSqYRQdpV93RuCOzg4vuXtR+gP0KQrus/P2ZCEPvU9cXF/2MIhXgOz207lv3iE2zGyNXld /n8spvWk+0bH5Zqd9Wcba/rGcBhmX9NKKDARZqjkv/zVEP1X97w1HsNYeUFNcg2lk9zQKb4v l1jx/Uz8ukzH2QNhU4R39dbF/4AwWuSVkGW6bTxHJqGs6YimbfdQqxTzmqFwz3JP0OtXX5q/ 6D4pHwcmJwEiDNzsBLl6skPSQ0Xyq3pua/qAP8MVm+YxCxJQITqZ8qjDLzoe7s9X6FLLC/DA L9kxl5saVSfDbuI3usH/emdtn0NA9/M7nfgih92zD92sl1yQXHT6BDa8xW1j+RU4P+E0wyd7 zgB2UeYgrp2IIcfG+xX2uFG5MJQ/nYfBoiALb0+dQHNHDtFnNGY3Oe8z1M9c5aDG3/s29QbJ +w7hEKKo9YMAEQEAAYkCJQQYAQgADwUCWj1QMgIbDAUJCZQmAAAKCRBasvrxexcr6qwvD/9b Rek3kfN8Q+jGrKl8qwY8HC5s4mhdDJZI/JP2FImf5J2+d5/e8UJ4fcsT79E0/FqX3Z9wZr6h sofPqLh1/YzDsYkZDHTYSGrlWGP/I5kXwUmFnBZHzM3WGrL3S7ZmCYMdudhykxXXjq7M6Do1 oxM8JofrXGtwBTLv5wfvvygJouVCVe87Ge7mCeY5vey1eUi4zSSF1zPpR6gg64w2g4TXM5qt SwkZVOv1g475LsGlYWRuJV8TA67yp1zJI7HkNqCo8KyHX0DPOh9c+Sd9ZX4aqKfqH9HIpnCL AYEgj7vofeix7gM3kQQmwynqq32bQGQBrKJEYp2vfeO30VsVx4dzuuiC5lyjUccVmw5D72J0 FlGrfEm0kw6D1qwyBg0SAMqamKN6XDdjhNAtXIaoA2UMZK/vZGGUKbqTgDdk0fnzOyb2zvXK CiPFKqIPAqKaDHg0JHdGI3KpQdRNLLzgx083EqEc6IAwWA6jSz+6lZDV6XDgF0lYqAYIkg3+ 6OUXUv6plMlwSHquiOc/MQXHfgUP5//Ra5JuiuyCj954FD+MBKIj8eWROfnzyEnBplVHGSDI ZLzL3pvV14dcsoajdeIH45i8DxnVm64BvEFHtLNlnliMrLOrk4shfmWyUqNlzilXN2BTFVFH 4MrnagFdcFnWYp1JPh96ZKjiqBwMv/H0kw==
Message-ID: <f229605c-914a-21cf-5217-6c314b3323a7@cs.tcd.ie>
Date: Sun, 16 Feb 2020 14:53:18 +0000
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1
MIME-Version: 1.0
In-Reply-To: <DF952AED-7578-47B8-B42F-F6A18A927C31@isode.com>
Content-Type: multipart/mixed; boundary="------------4AC2F9A080EA27E983F2AE65"
Content-Language: en-US
Archived-At: <https://mailarchive.ietf.org/arch/msg/cfrg/BmcBv733ocYbcx9wBnliKSlWmpU>
Subject: Re: [Cfrg] RGLC on draft-irtf-cfrg-kangarootwelve-01
X-BeenThere: cfrg@irtf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Crypto Forum Research Group <cfrg.irtf.org>
List-Unsubscribe: <https://www.irtf.org/mailman/options/cfrg>, <mailto:cfrg-request@irtf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/cfrg/>
List-Post: <mailto:cfrg@irtf.org>
List-Help: <mailto:cfrg-request@irtf.org?subject=help>
List-Subscribe: <https://www.irtf.org/mailman/listinfo/cfrg>, <mailto:cfrg-request@irtf.org?subject=subscribe>
X-List-Received-Date: Sun, 16 Feb 2020 14:53:30 -0000

Hiya,

On 16/02/2020 11:16, Alexey Melnikov wrote:
> Dear CFRG participants,
> 
> This message is starting 2 weeks RGLC on
> draft-irtf-cfrg-kangarootwelve-01 ("KangarooTwelve"), that will end
> on March 1st 2020. If you've read the document and think that it is
> ready (or not ready) for publication as an RFC, please send a message
> in reply to this email or directly to CFRG chairs
> (cfrg-chairs@ietf.org). If you have detailed comments, these would
> also be very helpful at this point.

I had my 1st read of this and think it needs a bit of
work, but am overall unclear if it ought be published
now. (I also looked back at the list archive messages
referring to k12.)

I don't think CFRG ought be publishing very novel
algorithm RFCs and am unclear how much study k12 has
gotten outside the author team. The main reference
given [1] has pointers to lots of work with titles that
mention reduced-round keccak but it's unclear (to me,
not having read 'em;-) how  relevant those are to k12.

[1] is also used as [KECCAK_CRYPTANALYSIS] in the draft
and is where the authors are pointing us to find
security analysis of k12. I don't think an author-
maintained web page like that is really good enough
as the key reference for an RFC like this.

I totally get why the authors would find that
easier/better, but that won't be true for a reader in
20 years time, so better to put in the precise
references now. That should also clarify the extent to
which those are about k12 (as defined here) and not
about something else.

I think the references really need fixing before this
ought be published. I'm not sure where the right line
ought be drawn in terms of maturity of an algorithm
before CFRG blesses it with an RFC. <4 years does seem
short, even if this is strongly based on keccak. (Hence
me being unsure overall.)

Separately, the draft could benefit from some guidance
as to when this is thought to be useful - presumably
that's when one wants a hash output that's >512 bits.
IIRC, there are other RFCs (forget numbers, sorry),
that describe how to get such outputs using standard
hash functions. If there are such RFCs, it'd be good
to reference those. Either way saying why and when this
is preferable to use of standard hash functions would
be good.

Other than the above, the draft seems clear (though
I didn't try implement) and many thanks for not
defining the usual pile of pointless variants/options:-)

Cheers,
S.

[1] https://keccak.team/third_party.html



> 
> 
> 
> Thank you,
> 
> Alexey, for CFRG chairs.
> 
> 
> 
> _______________________________________________ Cfrg mailing list 
> Cfrg@irtf.org https://www.irtf.org/mailman/listinfo/cfrg
>