git@vger.kernel.org mailing list mirror (one of many)
 help / color / mirror / code / Atom feed
From: "Philip Oakley" <philipoakley@iee.org>
To: "Stefan Beller" <sbeller@google.com>,
	"Junio C Hamano" <gitster@pobox.com>
Cc: "David Lang" <david@lang.hm>,
	"Ian Jackson" <ijackson@chiark.greenend.org.uk>,
	"Joey Hess" <id@joeyh.name>, <git@vger.kernel.org>
Subject: Re: SHA1 collisions found
Date: Fri, 24 Feb 2017 20:33:39 -0000	[thread overview]
Message-ID: <E817E45267184196A3832C3220075D14@PhilipOakley> (raw)
In-Reply-To: CAGZ79kaZWe-8pMZnQv7uZtr8wXWawFeJjUa68-b0oa4yFo-HcA@mail.gmail.com

From: "Stefan Beller" <sbeller@google.com>
> On Fri, Feb 24, 2017 at 10:14 AM, Junio C Hamano <gitster@pobox.com> 
> wrote:
>
>> you are inviting people to start using
>>
>>     md5,54ddf8d47340e048166c45f439ce65fd
>>
>> as object names.
>
> which might even be okay for specific subsets of operations.
> (e.g. all local work including staging things, making local "fixup" 
> commits)
>
> The addressing scheme should not be too hardcoded, we should rather
> treat it similar to the cipher schemes in pgp. The additional complexity 
> that
> we have is the longevity of existence of things, though.
>

One potential nicety of using the md5 is that it is a known `toy problem` 
solution that could be used to explore how things might be made to work, 
without any expectation that the temporary code is in any way an 
experimental part of regular code. Maybe. It's good to have a toy problem to 
work on.

There are other issue to be considered as well, such as validating a 
transition of identical blobs and trees (at some point there will for some 
users be a forced update of hash of unchanged code), which probably requires 
two way traversal.

Philip 


  parent reply	other threads:[~2017-02-24 20:33 UTC|newest]

Thread overview: 136+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-02-23 16:43 SHA1 collisions found Joey Hess
2017-02-23 17:00 ` David Lang
2017-02-23 17:02 ` Junio C Hamano
2017-02-23 17:12   ` David Lang
2017-02-23 20:49     ` Jakub Narębski
2017-02-23 20:57       ` Jeff King
2017-02-23 17:18   ` Junio C Hamano
2017-02-23 17:35   ` Joey Hess
2017-02-23 17:52     ` Linus Torvalds
2017-02-23 18:21       ` Joey Hess
2017-02-23 18:31         ` Joey Hess
2017-02-23 19:13           ` Morten Welinder
2017-02-24 15:52             ` Geert Uytterhoeven
2017-02-23 18:40         ` Linus Torvalds
2017-02-23 18:46           ` Jeff King
2017-02-23 19:09             ` Linus Torvalds
2017-02-23 19:32               ` Jeff King
2017-02-23 19:47                 ` Linus Torvalds
2017-02-23 19:57                   ` Jeff King
     [not found]                     ` <alpine.LFD.2.20.1702231428540.30435@i7.lan>
2017-02-23 22:43                       ` Jeff King
2017-02-23 22:50                         ` Linus Torvalds
2017-02-23 23:05                         ` Jeff King
2017-02-23 23:05                           ` [PATCH 1/3] add collision-detecting sha1 implementation Jeff King
2017-02-23 23:15                             ` Stefan Beller
2017-02-24  0:01                               ` Jeff King
2017-02-24  0:12                                 ` Linus Torvalds
2017-02-24  0:16                                   ` Jeff King
2017-02-23 23:05                           ` [PATCH 2/3] sha1dc: adjust header includes for git Jeff King
2017-02-23 23:06                           ` [PATCH 3/3] Makefile: add USE_SHA1DC knob Jeff King
2017-02-24 18:36                             ` HW42
2017-02-24 18:57                               ` Jeff King
2017-02-23 23:14                           ` SHA1 collisions found Linus Torvalds
2017-02-28 18:41                           ` Junio C Hamano
2017-02-28 19:07                             ` Junio C Hamano
2017-02-28 19:20                               ` Jeff King
2017-03-01  8:57                                 ` Dan Shumow
2017-02-28 19:34                               ` Linus Torvalds
2017-02-28 19:52                                 ` Shawn Pearce
2017-02-28 22:56                                   ` Linus Torvalds
2017-02-28 21:22                                 ` Dan Shumow
2017-02-28 22:50                                   ` Marc Stevens
2017-02-28 23:11                                     ` Linus Torvalds
2017-03-01 19:05                                       ` Jeff King
2017-02-23 20:47               ` Øyvind A. Holm
2017-02-23 20:46             ` Joey Hess
2017-02-23 18:42         ` Jeff King
2017-02-23 17:52     ` David Lang
2017-02-23 19:20   ` David Lang
2017-02-23 17:19 ` Linus Torvalds
2017-02-23 17:29   ` Linus Torvalds
2017-02-23 18:10   ` Joey Hess
2017-02-23 18:29     ` Linus Torvalds
2017-02-23 18:38     ` Junio C Hamano
2017-02-24  9:42 ` Duy Nguyen
2017-02-25 19:04   ` brian m. carlson
2017-02-27 13:29     ` René Scharfe
2017-02-28 13:25       ` brian m. carlson
2017-02-24 15:13 ` Ian Jackson
2017-02-24 17:04   ` ankostis
2017-02-24 17:23   ` Jason Cooper
2017-02-25 23:22     ` ankostis
2017-02-24 17:32   ` Junio C Hamano
2017-02-24 17:45     ` David Lang
2017-02-24 18:14       ` Junio C Hamano
2017-02-24 18:58         ` Stefan Beller
2017-02-24 19:20           ` Junio C Hamano
2017-02-24 20:05             ` ankostis
2017-02-24 20:32               ` Junio C Hamano
2017-02-25  0:31                 ` ankostis
2017-02-26  0:16                   ` Jason Cooper
2017-02-26 17:38                     ` brian m. carlson
2017-02-26 19:11                       ` Linus Torvalds
2017-02-26 21:38                         ` Ævar Arnfjörð Bjarmason
2017-02-26 21:52                           ` Jeff King
2017-02-27 13:00                             ` Transition plan for git to move to a new hash function Ian Jackson
2017-02-27 14:37                               ` Why BLAKE2? Markus Trippelsdorf
2017-02-27 15:42                                 ` Ian Jackson
2017-02-27 19:26                               ` Transition plan for git to move to a new hash function Tony Finch
2017-02-28 21:47                               ` brian m. carlson
2017-03-02 18:13                                 ` Ian Jackson
2017-03-04 22:49                                   ` brian m. carlson
2017-03-05 13:45                                     ` Ian Jackson
2017-03-05 23:45                                       ` brian m. carlson
2017-02-24 20:05             ` SHA1 collisions found Junio C Hamano
2017-02-24 20:33           ` Philip Oakley [this message]
2017-02-24 23:39     ` Jeff King
2017-02-25  0:39       ` Linus Torvalds
2017-02-25  0:54         ` Linus Torvalds
2017-02-25  1:16         ` Jeff King
2017-02-26 18:55           ` Junio C Hamano
2017-02-25  6:10         ` Junio C Hamano
2017-02-26  1:13           ` Jason Cooper
2017-02-26  5:18             ` Jeff King
2017-02-26 18:30               ` brian m. carlson
2017-03-02 21:46               ` Brandon Williams
2017-03-03 11:13                 ` Jeff King
2017-03-03 14:54                   ` Ian Jackson
2017-03-03 22:18                     ` Jeff King
2017-03-02 19:55         ` Linus Torvalds
2017-03-02 20:43           ` Junio C Hamano
2017-03-02 21:21             ` Linus Torvalds
2017-03-02 21:54               ` Joey Hess
2017-03-02 22:27                 ` Linus Torvalds
2017-03-03  1:50                   ` Mike Hommey
2017-03-03  2:19                     ` Linus Torvalds
2017-03-03 11:04           ` Jeff King
2017-03-03 21:47           ` Stefan Beller
2017-02-25  1:00       ` David Lang
2017-02-25  1:15         ` Stefan Beller
2017-02-25  1:21         ` Jeff King
2017-02-25  1:39           ` David Lang
2017-02-25  1:47             ` Jeff King
2017-02-25  1:56               ` David Lang
2017-02-25  2:28             ` Jacob Keller
2017-02-25  2:26           ` Jacob Keller
2017-02-25  5:39             ` grarpamp
2017-02-24 23:43     ` Ian Jackson
2017-02-25  0:06       ` Ian Jackson
2017-02-25 18:50     ` brian m. carlson
2017-02-25 19:26       ` Jeff King
2017-02-25 22:09         ` Mike Hommey
2017-02-26 17:38           ` brian m. carlson
2017-02-24 22:47 ` Jakub Narębski
2017-02-24 22:53   ` Santiago Torres
2017-02-24 23:05     ` Jakub Narębski
2017-02-24 23:24       ` Øyvind A. Holm
2017-02-24 23:06   ` Jeff King
2017-02-24 23:35     ` Jakub Narębski
2017-02-25 22:35     ` Lars Schneider
2017-02-26  0:46       ` Jeff King
2017-02-26 18:22         ` Junio C Hamano
2017-02-26 18:57     ` Thomas Braun
2017-02-26 21:30       ` Jeff King
2017-02-27  9:57         ` Geert Uytterhoeven
2017-02-27 10:43           ` Jeff King
2017-02-27 12:39             ` Morten Welinder

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

  List information: http://vger.kernel.org/majordomo-info.html

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=E817E45267184196A3832C3220075D14@PhilipOakley \
    --to=philipoakley@iee.org \
    --cc=david@lang.hm \
    --cc=git@vger.kernel.org \
    --cc=gitster@pobox.com \
    --cc=id@joeyh.name \
    --cc=ijackson@chiark.greenend.org.uk \
    --cc=sbeller@google.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
Code repositories for project(s) associated with this public inbox

	https://80x24.org/mirrors/git.git

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).