Re: [Bitcoin-development] bitcoin pull requests

[Melvin Carvalho <melvincarvalho@gmail.com>]

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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 ...
>>>>
>>>>
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>

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