Re: RFC v3: Another proposed hash function transition plan

[Jonathan Nieder <jrnieder@gmail.com>]

Hi,

Johannes Schindelin wrote:

> Sorry, you are asking cryptography experts to spend their time on the Git
> mailing list. I tried to get them to speak out on the Git mailing list.
> They respectfully declined.
>
> I can't fault them, they have real jobs to do, and none of their managers
> would be happy for them to educate the Git mailing list on matters of
> cryptography, not after what happened in 2005.

Fortunately we have had a few public comments from crypto specialists:

https://public-inbox.org/git/91a34c5b-7844-3db2-cf29-411df5bcf886@noekeon.org/
https://public-inbox.org/git/CAL9PXLzhPyE+geUdcLmd=pidT5P8eFEBbSgX_dS88knz2q_LSw@mail.gmail.com/
https://public-inbox.org/git/CAL9PXLxMHG1nP5_GQaK_WSJTNKs=_qbaL6V5v2GzVG=9VU2+gA@mail.gmail.com/
https://public-inbox.org/git/59BFB95D.1030903@st.com/
https://public-inbox.org/git/59C149A3.6080506@st.com/

[...]
> Let's be realistic. Git is pretty important to us, but it is not important
> enough to sway, say, Intel into announcing hardware support for SHA3.

Yes, I agree with this.  (Adoption by Git could lead to adoption by
some other projects, leading to more work on high quality software
implementations in projects like OpenSSL, but I am not convinced that
that would be a good thing for the world anyway.  There are downsides
to a proliferation of too many crypto primitives.  This is the basic
argument described in more detail at [1].)

[...]
> On Tue, 26 Sep 2017, Jason Cooper wrote:

>> For my use cases, as a user of git, I have a plan to maintain provable
>> integrity of existing objects stored in git under sha1 while migrating
>> away from sha1.  The same plan works for migrating away from SHA2 or
>> SHA3 when the time comes.
>
> Please do not make the mistake of taking your use case to be a template
> for everybody's use case.

That said, I'm curious at what plan you are alluding to.  Is it
something that could benefit others on the list?

Thanks,
Jonathan

[1] https://www.imperialviolet.org/2017/05/31/skipsha3.html