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 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 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 > wrote: > > > > > > > >> > > > >> > > > >> > > > >> On 1 April 2013 20:28, Petr Praus 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 > 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 >