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From: Joan Daemen <jda@noekeon.org>
To: Johannes Schindelin <Johannes.Schindelin@gmx.de>,
	Gilles Van Assche <gilles.vanassche@st.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	demerphq <demerphq@gmail.com>,
	Brandon Williams <bmwill@google.com>,
	Junio C Hamano <gitster@pobox.com>,
	Jonathan Nieder <jrnieder@gmail.com>,
	Git Mailing List <git@vger.kernel.org>,
	Stefan Beller <sbeller@google.com>,
	Jonathan Tan <jonathantanmy@google.com>,
	Jeff King <peff@peff.net>, David Lang <david@lang.hm>,
	"brian m. carlson" <sandals@crustytoothpaste.net>,
	Keccak Team <keccak@noekeon.org>
Subject: Re: RFC v3: Another proposed hash function transition plan
Date: Fri, 29 Sep 2017 16:54:23 +0200
Message-ID: <acd96750-c165-650c-c67f-44465f2075f2@noekeon.org> (raw)
In-Reply-To: <alpine.DEB.2.21.1.1709291416290.40514@virtualbox>

Dear Johannes,

if ever there was a SHA-2 competition, it must have been held inside 
NSA:-) But maybe you are confusing with the SHA-3 competition. In any 
case, when considering SHA-2 vs SHA-3 for usage in git, you may have a 
look at arguments we give in the following blogpost:

https://keccak.team/2017/open_source_crypto.html

Kind regards,

Joan Daemen

On 29/09/17 15:17, Johannes Schindelin wrote:
> Hi Gilles,
>
> On Tue, 19 Sep 2017, Gilles Van Assche wrote:
>
>> On 19/09/17 00:16, Johannes Schindelin wrote:
>>>>> SHA-256 got much more cryptanalysis than SHA3-256 […].
>>>> I do not think this is true.
>>> Please read what I said again: SHA-256 got much more cryptanalysis
>>> than SHA3-256.
>> Indeed. What I meant is that SHA3-256 got at least as much cryptanalysis
>> as SHA-256. :-)
> Oh? I got the opposite impression... I got the impression that *everybody*
> in the field banged on all the SHA-2 candidates because everybody was
> worried that SHA-1 would be utterly broken soon, and I got the impression
> that after this SHA-2 competition, people were less worried?
>
> Besides, I would expect that the difference in age (at *least* 7 years by
> my humble arithmetic skills) to make a difference...
>
>>> I never said that SHA3-256 got little cryptanalysis. Personally, I
>>> think that SHA3-256 got a ton more cryptanalysis than SHA-1, and that
>>> SHA-256 *still* got more cryptanalysis. But my opinion does not count,
>>> really. However, the two experts I pestered with questions over
>>> questions left me with that strong impression, and their opinion does
>>> count.
>> OK, I respect your opinion and that of your two experts. Yet, the "much
>> more" part of your statement, in particular, is something that may
>> require a bit more explanations.
> I would also like to point out the ubiquitousness of SHA-256. I have been
> asked to provide SHA-256 checksums for the downloads of Git for Windows,
> but not SHA3-256...
>
> And this is a practically-relevant thing: the more users of an algorithm
> there are, the more high-quality implementations you can choose from. And
> this becomes relevant, say, when you have to switch implementations due to
> license changes (*cough, cough looking in OpenSSL's direction*). Or when
> you have to support the biggest Git repository on this planet and have to
> eek out 5-10% more performance using the latest hardware. All of a sudden,
> your consideration cannot only be "security of the algorithm" any longer.
>
> Having said that, I am *really* happy to have SHA3-256 as a valid fallback
> option in case SHA-256 should be broken.
>
> Ciao,
> Johannes


  reply index

Thread overview: 113+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-04  1:12 RFC: " Jonathan Nieder
2017-03-05  2:35 ` Linus Torvalds
2017-03-06  0:26   ` brian m. carlson
2017-03-06 18:24     ` Brandon Williams
2017-06-15 10:30       ` Which hash function to use, was " Johannes Schindelin
2017-06-15 11:05         ` Mike Hommey
2017-06-15 13:01           ` Jeff King
2017-06-15 16:30             ` Ævar Arnfjörð Bjarmason
2017-06-15 19:34               ` Johannes Schindelin
2017-06-15 21:59                 ` Adam Langley
2017-06-15 22:41                   ` brian m. carlson
2017-06-15 23:36                     ` Ævar Arnfjörð Bjarmason
2017-06-16  0:17                       ` brian m. carlson
2017-06-16  6:25                         ` Ævar Arnfjörð Bjarmason
2017-06-16 13:24                           ` Johannes Schindelin
2017-06-16 17:38                             ` Adam Langley
2017-06-16 20:52                               ` Junio C Hamano
2017-06-16 21:12                                 ` Junio C Hamano
2017-06-16 21:24                                   ` Jonathan Nieder
2017-06-16 21:39                                     ` Ævar Arnfjörð Bjarmason
2017-06-16 20:42                             ` Jeff King
2017-06-19  9:26                               ` Johannes Schindelin
2017-06-15 21:10             ` Mike Hommey
2017-06-16  4:30               ` Jeff King
2017-06-15 17:36         ` Brandon Williams
2017-06-15 19:20           ` Junio C Hamano
2017-06-15 19:13         ` Jonathan Nieder
2017-03-07  0:17   ` RFC v3: " Jonathan Nieder
2017-03-09 19:14     ` Shawn Pearce
2017-03-09 20:24       ` Jonathan Nieder
2017-03-10 19:38         ` Jeff King
2017-03-10 19:55           ` Jonathan Nieder
2017-09-28  4:43       ` [PATCH v4] technical doc: add a design doc for hash function transition Jonathan Nieder
2017-09-29  6:06         ` Junio C Hamano
2017-09-29  8:09           ` Junio C Hamano
2017-09-29 17:34           ` Jonathan Nieder
2017-10-02  8:25             ` Junio C Hamano
2017-10-02 19:41             ` Jason Cooper
2017-10-02  9:02         ` Junio C Hamano
2017-10-02 19:23         ` Jason Cooper
2017-10-03  5:40         ` Junio C Hamano
2017-10-03 13:08           ` Jason Cooper
2017-10-04  1:44         ` Junio C Hamano
2017-09-06  6:28     ` RFC v3: Another proposed hash function transition plan Junio C Hamano
2017-09-08  2:40       ` Junio C Hamano
2017-09-08  3:34         ` Jeff King
2017-09-11 18:59         ` Brandon Williams
2017-09-13 12:05           ` Johannes Schindelin
2017-09-13 13:43             ` demerphq
2017-09-13 22:51               ` Jonathan Nieder
2017-09-14 18:26                 ` Johannes Schindelin
2017-09-14 18:40                   ` Jonathan Nieder
2017-09-14 22:09                     ` Johannes Schindelin
2017-09-13 23:30               ` Linus Torvalds
2017-09-14 18:45                 ` Johannes Schindelin
2017-09-18 12:17                   ` Gilles Van Assche
2017-09-18 22:16                     ` Johannes Schindelin
2017-09-19 16:45                       ` Gilles Van Assche
2017-09-29 13:17                         ` Johannes Schindelin
2017-09-29 14:54                           ` Joan Daemen [this message]
2017-09-29 22:33                             ` Johannes Schindelin
2017-09-30 22:02                               ` Joan Daemen
2017-10-02 14:26                                 ` Johannes Schindelin
2017-09-18 22:25                     ` Jonathan Nieder
2017-09-26 17:05                   ` Jason Cooper
2017-09-26 22:11                     ` Johannes Schindelin
2017-09-26 22:25                       ` [PATCH] technical doc: add a design doc for hash function transition Stefan Beller
2017-09-26 23:38                         ` Jonathan Nieder
2017-09-26 23:51                       ` RFC v3: Another proposed hash function transition plan Jonathan Nieder
2017-10-02 14:54                         ` Jason Cooper
2017-10-02 16:50                           ` Brandon Williams
2017-10-02 14:00                       ` Jason Cooper
2017-10-02 17:18                         ` Linus Torvalds
2017-10-02 19:37                           ` Jeff King
2017-09-13 16:30             ` Jonathan Nieder
2017-09-13 21:52               ` Junio C Hamano
2017-09-13 22:07                 ` Stefan Beller
2017-09-13 22:18                   ` Jonathan Nieder
2017-09-14  2:13                     ` Junio C Hamano
2017-09-14 15:23                       ` Johannes Schindelin
2017-09-14 15:45                         ` demerphq
2017-09-14 22:06                           ` Johannes Schindelin
2017-09-13 22:15                 ` Junio C Hamano
2017-09-13 22:27                   ` Jonathan Nieder
2017-09-14  2:10                     ` Junio C Hamano
2017-09-14 12:39               ` Johannes Schindelin
2017-09-14 16:36                 ` Brandon Williams
2017-09-14 18:49                 ` Jonathan Nieder
2017-09-15 20:42                   ` Philip Oakley
2017-03-05 11:02 ` RFC: " David Lang
     [not found]   ` <CA+dhYEXHbQfJ6KUB1tWS9u1MLEOJL81fTYkbxu4XO-i+379LPw@mail.gmail.com>
2017-03-06  9:43     ` Jeff King
2017-03-06 23:40   ` Jonathan Nieder
2017-03-07  0:03     ` Mike Hommey
2017-03-06  8:43 ` Jeff King
2017-03-06 18:39   ` Jonathan Tan
2017-03-06 19:22     ` Linus Torvalds
2017-03-06 19:59       ` Brandon Williams
2017-03-06 21:53       ` Junio C Hamano
2017-03-07  8:59     ` Jeff King
2017-03-06 18:43   ` Junio C Hamano
2017-03-07 18:57 ` Ian Jackson
2017-03-07 19:15   ` Linus Torvalds
2017-03-08 11:20     ` Ian Jackson
2017-03-08 15:37       ` Johannes Schindelin
2017-03-08 15:40       ` Johannes Schindelin
2017-03-20  5:21         ` Use base32? Jason Hennessey
2017-03-20  5:58           ` Michael Steuer
2017-03-20  8:05             ` Jacob Keller
2017-03-21  3:07               ` Michael Steuer
2017-03-13  9:24 ` RFC: Another proposed hash function transition plan The Keccak Team
2017-03-13 17:48   ` Jonathan Nieder
2017-03-13 18:34     ` ankostis
2017-03-17 11:07       ` Johannes Schindelin

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