Re: Hash algorithm analysis

Hi Brian,

On Fri, 20 Jul 2018, brian m. carlson wrote:

On Mon, Jun 11, 2018 at 12:29:42PM -0700, Jonathan Nieder wrote:

quoted

My understanding of the discussion so far:

Keccak team encourages us[1] to consider a variant like K12 instead of
SHA3.

AGL explains[2] that the algorithms considered all seem like
reasonable choices and we should decide using factors like
implementation ease and performance.

If we choose a Keccak-based function, AGL also[3] encourages using a
variant like K12 instead of SHA3.

Dscho strongly prefers[4] SHA-256, because of
- wide implementation availability, including in future hardware
- has been widely analyzed
- is fast

Yves Orton and Linus Torvalds prefer[5] SHA3 over SHA2 because of how
it is constructed.

I know this discussion has sort of petered out, but I'd like to see if
we can revive it.  I'm writing index v3 and having a decision would help
me write tests for it.

To summarize the discussion that's been had in addition to the above,
Ævar has also stated a preference for SHA-256 and I would prefer BLAKE2b
over SHA-256 over SHA3-256, although any of them would be fine.

Are there other contributors who have a strong opinion?  Are there
things I can do to help us coalesce around an option?

Do you really want to value contributors' opinion more than
cryptographers'? I mean, that's exactly what got us into this hard-coded
SHA-1 mess in the first place.

And to set the record straight: I do not have a strong preference of the
hash algorithm. But cryprographers I have the incredible luck to have
access to, by virtue of being a colleague, did mention their preference.

I see no good reason to just blow their advice into the wind.

Ciao,
Dscho