From: Wladimir <laanwj@gmail•com>
To: Roy Badami <roy@gnomon•org.uk>
Cc: Bitcoin Dev <bitcoin-development@lists•sourceforge.net>
Subject: Re: [Bitcoin-development] bitcoin pull requests
Date: Wed, 3 Apr 2013 05:41:26 +0200 [thread overview]
Message-ID: <CA+s+GJBLUTfu8q2zE4pJ+HO5u-GweGNKZebV=XRhBe7TCPggPg@mail.gmail.com> (raw)
In-Reply-To: <20130401225417.GV65880@giles.gnomon.org.uk>
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Maybe now that bitcoin is growing out of the toy phase it's an idea to
start gpg signing commits, like the Linux kernel (
https://lwn.net/Articles/466468/).
But I suppose then we can't use github anymore to merge as-is and need
manual steps?
Wladimir
On Tue, Apr 2, 2013 at 12:54 AM, Roy Badami <roy@gnomon•org.uk> wrote:
> And the moment I hit send I realised it's not necessarily true.
> Conceivably, a collision attack might help you craft two commits (one
> good, one bad) with the same hash.
>
> But I still maintain what I just posted is true: if someone gets
> malicious code into the repo, it's going to be by social engineering,
> not by breaking the cyrpto.
>
> roy
>
>
> On Mon, Apr 01, 2013 at 11:51:07PM +0100, Roy Badami wrote:
> > The attack Schneier is talking about is a collision attack (i.e. it
> > creates two messages with the same hash, but you don't get to choose
> > either of the messages). It's not a second preimage attack, which is
> > what you would need to be able to create a message that hashes to the
> > same value of an existing message.
> >
> > (And it neither have anything to do with the birthday paradox, BTW -
> > which relates to the chance of eventually finding two messages that
> > hash to the same value by pure change)
> >
> > If someone gets malicious code into the repo, it's going to be by
> > social engineering, not by breaking the cyrpto.
> >
> > roy
> >
> > On Tue, Apr 02, 2013 at 12:27:51AM +0200, Melvin Carvalho wrote:
> > > On 2 April 2013 00:10, Will <will@phase•net> wrote:
> > >
> > > > The threat of a SHA1 collision attack to insert a malicious pull
> request
> > > > are tiny compared with the other threats - e.g. github being
> compromised,
> > > > one of the core developers' passwords being compromised, one of the
> core
> > > > developers going rogue, sourceforge (distribution site) being
> compromised
> > > > etc etc... believe me there's a lot more to worry about than a SHA1
> > > > attack...
> > > >
> > > > Not meaning to scare, just to put things in perspective - this is
> why we
> > > > all need to peer review each others commits and keep an eye out for
> > > > suspicious commits, leverage the benefits of this project being open
> source
> > > > and easily peer reviewed.
> > > >
> > >
> > > Very good points, and I think you're absolutely right.
> > >
> > > But just running the numbers, to get the picture, based of scheiner's
> > > statistics:
> > >
> > > http://www.schneier.com/blog/archives/2012/10/when_will_we_se.html
> > >
> > > We're talking about a million terrahashes = 2^60 right?
> > >
> > > With the block chain, you only have a 10 minute window, but with source
> > > code you have a longer time to prepare.
> > >
> > > Couldnt this be done with an ASIC in about a week?
> > >
> > >
> > >
> > > >
> > > > Will
> > > >
> > > >
> > > > On 1 April 2013 23:52, Melvin Carvalho <melvincarvalho@gmail•com>
> wrote:
> > > >
> > > >>
> > > >>
> > > >>
> > > >> On 1 April 2013 20:28, Petr Praus <petr@praus•net> wrote:
> > > >>
> > > >>> An attacker would have to find a collision between two specific
> pieces
> > > >>> of code - his malicious code and a useful innoculous code that
> would be
> > > >>> accepted as pull request. This is the second, much harder case in
> the
> > > >>> birthday problem. When people talk about SHA-1 being broken they
> actually
> > > >>> mean the first case in the birthday problem - find any two
> arbitrary values
> > > >>> that hash to the same value. So, no I don't think it's a feasible
> attack
> > > >>> vector any time soon.
> > > >>>
> > > >>> Besides, with that kind of hashing power, it might be more
> feasible to
> > > >>> cause problems in the chain by e.g. constantly splitting it.
> > > >>>
> > > >>
> > > >> OK, maybe im being *way* too paranoid here ... but what if someone
> had
> > > >> access to github, could they replace one file with one they had
> prepared at
> > > >> some point?
> > > >>
> > > >>
> > > >>>
> > > >>>
> > > >>> On 1 April 2013 03:26, Melvin Carvalho <melvincarvalho@gmail•com>
> wrote:
> > > >>>
> > > >>>> I was just looking at:
> > > >>>>
> > > >>>> https://bitcointalk.org/index.php?topic=4571.0
> > > >>>>
> > > >>>> I'm just curious if there is a possible attack vector here based
> on the
> > > >>>> fact that git uses the relatively week SHA1
> > > >>>>
> > > >>>> Could a seemingly innocuous pull request generate another file
> with a
> > > >>>> backdoor/nonce combination that slips under the radar?
> > > >>>>
> > > >>>> Apologies if this has come up before ...
> > > >>>>
> > > >>>>
> > > >>>>
> ------------------------------------------------------------------------------
> > > >>>> Own the Future-Intel® Level Up Game Demo Contest 2013
> > > >>>> Rise to greatness in Intel's independent game demo contest.
> > > >>>> Compete for recognition, cash, and the chance to get your game
> > > >>>> on Steam. $5K grand prize plus 10 genre and skill prizes.
> > > >>>> Submit your demo by 6/6/13. http://p.sf.net/sfu/intel_levelupd2d
> > > >>>> _______________________________________________
> > > >>>> Bitcoin-development mailing list
> > > >>>> Bitcoin-development@lists•sourceforge.net
> > > >>>> https://lists.sourceforge.net/lists/listinfo/bitcoin-development
> > > >>>>
> > > >>>>
> > > >>>
> > > >>
> > > >>
> > > >>
> ------------------------------------------------------------------------------
> > > >> Own the Future-Intel® Level Up Game Demo Contest 2013
> > > >> Rise to greatness in Intel's independent game demo contest.
> > > >> Compete for recognition, cash, and the chance to get your game
> > > >> on Steam. $5K grand prize plus 10 genre and skill prizes.
> > > >> Submit your demo by 6/6/13. http://p.sf.net/sfu/intel_levelupd2d
> > > >> _______________________________________________
> > > >> Bitcoin-development mailing list
> > > >> Bitcoin-development@lists•sourceforge.net
> > > >> https://lists.sourceforge.net/lists/listinfo/bitcoin-development
> > > >>
> > > >>
> > > >
> >
> > >
> ------------------------------------------------------------------------------
> > > Own the Future-Intel® Level Up Game Demo Contest 2013
> > > Rise to greatness in Intel's independent game demo contest.
> > > Compete for recognition, cash, and the chance to get your game
> > > on Steam. $5K grand prize plus 10 genre and skill prizes.
> > > Submit your demo by 6/6/13. http://p.sf.net/sfu/intel_levelupd2d
> >
> > > _______________________________________________
> > > Bitcoin-development mailing list
> > > Bitcoin-development@lists•sourceforge.net
> > > https://lists.sourceforge.net/lists/listinfo/bitcoin-development
> >
> >
> >
> ------------------------------------------------------------------------------
> > Own the Future-Intel® Level Up Game Demo Contest 2013
> > Rise to greatness in Intel's independent game demo contest.
> > Compete for recognition, cash, and the chance to get your game
> > on Steam. $5K grand prize plus 10 genre and skill prizes.
> > Submit your demo by 6/6/13. http://p.sf.net/sfu/intel_levelupd2d
> > _______________________________________________
> > Bitcoin-development mailing list
> > Bitcoin-development@lists•sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/bitcoin-development
> >
>
>
> ------------------------------------------------------------------------------
> Own the Future-Intel® Level Up Game Demo Contest 2013
> Rise to greatness in Intel's independent game demo contest.
> Compete for recognition, cash, and the chance to get your game
> on Steam. $5K grand prize plus 10 genre and skill prizes.
> Submit your demo by 6/6/13. http://p.sf.net/sfu/intel_levelupd2d
> _______________________________________________
> Bitcoin-development mailing list
> Bitcoin-development@lists•sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/bitcoin-development
>
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next prev parent reply other threads:[~2013-04-03 3:41 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-01 8:26 Melvin Carvalho
2013-04-01 18:28 ` Petr Praus
2013-04-01 21:52 ` Melvin Carvalho
2013-04-01 22:10 ` Will
2013-04-01 22:27 ` Melvin Carvalho
2013-04-01 22:51 ` Roy Badami
2013-04-01 22:54 ` Roy Badami
2013-04-03 3:41 ` Wladimir [this message]
2013-04-03 3:51 ` Jeff Garzik
2013-04-03 15:52 ` grarpamp
2013-04-03 16:05 ` Gavin Andresen
2013-04-03 16:23 ` grarpamp
[not found] ` <CAAS2fgT06RHBO_0stKQAYLPB39ZAzaCVduFZJROjSzXUP4Db+g@mail.gmail.com>
2013-04-03 18:12 ` grarpamp
2013-04-04 9:11 ` Mike Hearn
2013-04-04 10:04 ` Mike Hearn
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