On Tue, Apr 29, 2008 at 9:21 AM, Andreas Ericsson <ae@xxxxxx> wrote: > Russ Dill wrote: > If the server is hacked and objects are replaced, they will either > no longer match their cryptographic signature, meaning they'll be > new objects or git will determine that they are corrupt, or they We were assuming here that once SHA-1 is broken really determined hackers will be able to come up with objects that -do- match the SHA-1, so the above is not relevant. > *will* match an existing object, but then that object won't be > propagated to other repositories since git refuses to overwrite > already existing objects. [...] What about new users cloning the repo? They're just out of luck? I don't think this argument holds, if we want to 'advertise' that git is cryptographically secure we can do so only as long as our hashing algorithm is. (As such, should SHA-1 ever be fully broken we'd need to either switch to another algorithm or stop advertising being cryptographically secure.) > [...] Either way, gits refusal to overwrite > objects it already has plays a part in making malicious actions > futile, since malicious code is only worth something if it's > propagated and actually used. Of course this is true, it makes it a lot harder to do damage, but it doesn't eliminate the problem, it's just a free 'extra protection'. Yes, malicious code is only worth something if it's propagated and actually used, no, it is not impossible to do so in git if/when SHA-1 turns out to have collisions every other file. -- Cheers, Sverre Rabbelier -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
