Subject: Re: [PATCH v3 10/12] Add a base implementation of SHA-256 support

From: Jakub Narebski <[email-masked]>
Date: Sat, 27 Oct 2018 16:34:03 +0200

"brian m. carlson" <[email-masked]> writes:

> 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.

Even if we have decided to not repeat the reasoning behind the need to
switch away from SHA-1, and the choice of SHA-256 as NewHash, I think we
should provide _references_ to those discussion (either to the mailing
list via public-inbox, or via Git Rev News articles).

So the above paragraph would be:

  SHA-1 is weak and we need to transition to a new hash function [1].  For
  some time, we have referred to this new function as NewHash.  Recently,
  we decided to pick SHA-256 as NewHash [2].

  [1]: <some URL>
  [2]: <some URL>

>
> 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.  Pull in the update and final functions from the SHA-1 block
> implementation, as we know these function correctly with all compilers.
> This implementation is slower than SHA-1, but more performant
> implementations will be introduced in future commits.
>
> 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.
>
> Signed-off-by: brian m. carlson <[email-masked]>

Best,
-- 
Jakub Narębski