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

"brian m. carlson" [off-list ref] 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 <redacted>

Best,
-- 
Jakub Narębski