From: David Lang <david@lang.hm>
Date: Fri, 24 Feb 2017 17:45:55 GMT
Subject: Re: SHA1 collisions found
Message-ID: <nycvar.QRO.7.75.62.1702240943540.6590@qynat-yncgbc>
In-Reply-To: <xmqq60jz5wbm.fsf@gitster.mtv.corp.google.com>

On Fri, 24 Feb 2017, Junio C Hamano wrote:

> *1* In the above toy example, length being 40 vs 64 is used as a
>    sign between SHA-1 and the new hash, and careful readers may
>    wonder if we should use sha-3,20769079d22... or something like
>    that that more explicity identifies what hash is used, so that
>    we can pick a hash whose length is 64 when we transition again.
>
>    I personally do not think such a prefix is necessary during the
>    first transition; we will likely to adopt a new hash again, and
>    at that point that third one can have a prefix to differenciate
>    it from the second one.

as the saying goes "in computer science the interesting numbers are 0, 1, and 
many", does it really simplify things much to support 2 hashes vs supporting 
more so that this issue doesn't have to be revisited? (other than selecting new 
hashes over time)

David Lang