From: Duy Nguyen <pclouds@gmail.com>
To: "brian m. carlson" <sandals@crustytoothpaste.net>,
"Git Mailing List" <git@vger.kernel.org>,
"Jeff King" <peff@peff.net>, "Derrick Stolee" <stolee@gmail.com>,
"Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
Subject: Re: [PATCH v2 10/13] Add a base implementation of SHA-256 support
Date: Tue, 16 Oct 2018 16:59:23 +0200 [thread overview]
Message-ID: <CACsJy8D_9cwE_Xf7d3rWj_aq8uNUY0wpz8ydLLgvdpV0rQYbrg@mail.gmail.com> (raw)
In-Reply-To: <20181015233035.GB432229@genre.crustytoothpaste.net>
On Tue, Oct 16, 2018 at 1:31 AM brian m. carlson
<sandals@crustytoothpaste.net> wrote:
>
> On Mon, Oct 15, 2018 at 04:59:12PM +0200, Duy Nguyen wrote:
> > On Mon, Oct 15, 2018 at 4:23 AM brian m. carlson
> > <sandals@crustytoothpaste.net> wrote:
> > >
> > > SHA-1 is weak and we need to transition to a new hash function. For
> > > some time, we have referred to this new function as NewHash. Recently,
> > > we decided to pick SHA-256 as NewHash.
> > >
> > > Add a basic implementation of SHA-256 based off libtomcrypt, which is in
> > > the public domain. Optimize it and restructure it to meet our coding
> > > standards. Place it in a directory called "sha256" where it and any
> > > future implementations can live so as to avoid a proliferation of
> > > implementation directories.
> > >
> > > Wire up SHA-256 in the list of hash algorithms, and add a test that the
> > > algorithm works correctly.
> > >
> > > Note that with this patch, it is still not possible to switch to using
> > > SHA-256 in Git. Additional patches are needed to prepare the code to
> > > handle a larger hash algorithm and further test fixes are needed.
> >
> > At some point I assume SHA-256 will become functional and be part of a
> > git release without all file formats updated to support multiple
> > hashes. Should we somehow discourage the user from using it because it
> > will break when all file formats are finally updated?
>
> In order to activate SHA-256 in the codebase, currently you need a patch
> to force it on. Otherwise, the code is simply inert and does nothing
> (other than in the test-tool). I've included the patch below so you can
> see what it does (or if you want to play around with it).
>
> Without this patch, Git remains fully SHA-1 and can't access any of the
> SHA-256 code. I have some very preliminary patches that do wire up
> extensions.objectFormat (branch object-id-part15 [sic]) but I haven't
> picked them up in a while. (I need to finish test fixes first.)
Ah, I thought that extensions.objectFormat and setup changes already
landed (I think I saw that series on this list). Sorry for the noise.
--
Duy
next prev parent reply other threads:[~2018-10-16 14:59 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-15 2:18 [PATCH v2 00/13] Base SHA-256 implementation brian m. carlson
2018-10-15 2:18 ` [PATCH v2 01/13] sha1-file: rename algorithm to "sha1" brian m. carlson
2018-10-16 15:17 ` Duy Nguyen
2018-10-17 22:53 ` brian m. carlson
2018-10-15 2:18 ` [PATCH v2 02/13] sha1-file: provide functions to look up hash algorithms brian m. carlson
2018-10-17 13:32 ` SZEDER Gábor
2018-10-15 2:18 ` [PATCH v2 03/13] hex: introduce functions to print arbitrary hashes brian m. carlson
2018-10-16 1:54 ` Junio C Hamano
2018-10-17 23:49 ` brian m. carlson
2018-10-15 2:18 ` [PATCH v2 04/13] cache: make hashcmp and hasheq work with larger hashes brian m. carlson
2018-10-16 15:44 ` Duy Nguyen
2018-10-15 2:18 ` [PATCH v2 05/13] t: add basic tests for our SHA-1 implementation brian m. carlson
2018-10-15 2:18 ` [PATCH v2 06/13] t: make the sha1 test-tool helper generic brian m. carlson
2018-10-15 2:18 ` [PATCH v2 07/13] sha1-file: add a constant for hash block size brian m. carlson
2018-10-15 2:18 ` [PATCH v2 08/13] t/helper: add a test helper to compute hash speed brian m. carlson
2018-10-15 2:18 ` [PATCH v2 09/13] commit-graph: convert to using the_hash_algo brian m. carlson
2018-10-15 15:10 ` Derrick Stolee
2018-10-15 2:18 ` [PATCH v2 10/13] Add a base implementation of SHA-256 support brian m. carlson
2018-10-15 14:59 ` Duy Nguyen
2018-10-15 23:30 ` brian m. carlson
2018-10-16 14:59 ` Duy Nguyen [this message]
2018-10-17 16:12 ` SZEDER Gábor
2018-10-17 23:04 ` brian m. carlson
2018-10-15 2:18 ` [PATCH v2 11/13] sha256: add an SHA-256 implementation using libgcrypt brian m. carlson
2018-10-15 2:18 ` [PATCH v2 12/13] hash: add an SHA-256 implementation using OpenSSL brian m. carlson
2018-10-16 15:36 ` Duy Nguyen
2018-10-15 2:19 ` [PATCH v2 13/13] commit-graph: specify OID version for SHA-256 brian m. carlson
2018-10-15 15:11 ` Derrick Stolee
2018-10-16 2:00 ` Junio C Hamano
2018-10-16 22:39 ` brian m. carlson
2018-10-16 15:35 ` Duy Nguyen
2018-10-16 16:01 ` Derrick Stolee
2018-10-16 16:09 ` Duy Nguyen
2018-10-16 22:44 ` brian m. carlson
2018-10-17 14:31 ` Duy Nguyen
2018-10-18 0:06 ` brian m. carlson
2018-10-18 13:03 ` Derrick Stolee
2018-10-19 22:21 ` brian m. carlson
2018-10-17 12:21 ` Derrick Stolee
2018-10-17 22:38 ` brian m. carlson
2018-10-16 2:00 ` [PATCH v2 00/13] Base SHA-256 implementation Junio C Hamano
2018-10-16 4:01 ` Junio C Hamano
2018-10-16 22:45 ` brian m. carlson
2018-10-16 15:39 ` Duy Nguyen
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