From: Junio C Hamano <gitster@pobox.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jeff King <peff@peff.net>,
Ian Jackson <ijackson@chiark.greenend.org.uk>,
Joey Hess <id@joeyh.name>, Git Mailing List <git@vger.kernel.org>
Subject: Re: SHA1 collisions found
Date: Thu, 02 Mar 2017 12:43:50 -0800 [thread overview]
Message-ID: <xmqqk287be9l.fsf@gitster.mtv.corp.google.com> (raw)
In-Reply-To: <CA+55aFwXaSAMF41Dz3u3nS+2S24umdUFv0+k+s18UyPoj+v31g@mail.gmail.com> (Linus Torvalds's message of "Thu, 2 Mar 2017 11:55:45 -0800")
Linus Torvalds <torvalds@linux-foundation.org> writes:
> Anyway, I do have a suggestion for what the "object version" would be,
> but I'm not even going to mention it, because I want people to first
> think about the _concept_ and not the implementation.
>
> So: What do you think about the concept?
My reaction heavily depends on how that "object version" thing
works. When I think I have "variant #1" of an object and say
have 860cd699c285f02937a2edbdb78e8231292339a5#1
is there any guarantee that the other end has a (small) set of
different objects all sharing the same SHA-1 and it thinks it has
"variant #1" only when it has the same thing as I have (otherwise,
it may have "variant #2" that is an unrelated object but happens to
share the same hash)? If so, I think I understand how things would
work within your "concept". But otherwise, I am not really sure.
Would "object version" be like a truncated SHA-1 over the same data
but with different IV or something, i.e. something that guarantees
anybody would get the same result given the data to be hashed?
next prev parent reply other threads:[~2017-03-02 20:45 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
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 [this message]
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=xmqqk287be9l.fsf@gitster.mtv.corp.google.com \
--to=gitster@pobox.com \
--cc=git@vger.kernel.org \
--cc=id@joeyh.name \
--cc=ijackson@chiark.greenend.org.uk \
--cc=peff@peff.net \
--cc=torvalds@linux-foundation.org \
/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).