After some difficulty fairbirx was released recently. Shortly after many early adopters had their blocks invalidated. There has been some speculation that an unknown attacker executed a 51% attack effectivly stealing approximatly 1,600 blocks. Lolcust and I were talking about this and decided that making our conversation public might do some good. So I'm posting our conversation below.
Additional info:
Fairbrix Source is here:
https://github.com/coblee/FairbrixWindows binaries here:
http://www.mediafire.com/?9gc2If you use IRC a fairbirx channel is on freenode at #fairbrix
Here is the conversation between Lolcust and I:
OneMINER:
I was wondering how an accidental 51% attack would occur. If I have some huge farm of CPUs and I start hashing for a coin I do work on the NEXT BLOCK right? Why would a legit miner with legit software start a chain over accidentally?
Based on what I know (and thats not much). The accidental argument sounds like BS. Please correct me if I'm wrong.
Thanks.
Lolcust:
FBX is tiny. As in, below 20% of TBX (and TBX isn't big yet).
I find it far from implausible that the net got fragmented in an uncanny way and then reconstituted in a manner that orphaned everything.
In fact, I would not call it "impossible" that it was one of those dudes with "fixed up configs" reasserting dominance (in case of a fork, the chain with highest sum of work asserts dominance, and someone who mined for all the time that re-launch was prepared definitely has higher sum of work)
Only competent chain analysis will reveal the truth, but again, the only reason GG "relaunch" did not result in pwnt chain re-asserting itself was that I changed the start-message thingamabobbles for GG2, so that the "oldnet" couldn't chat with "newnet"
OneMINER:
I respect your opinion but frankly that's ridiculous. Fracturing net? So fractured that traffic doesn't get rerouted? I think not. Also if a person edited the faulty software so that it was compatible with the newer software why would the program try to start a new chain again? If it can communicate with other nodes it would download the chain and hash at it like a normal miner. The fact that it orphaned blocks is proof that it communicates with other nodes.
I ask you to reconsider your comments and if you so choose to throw your weight at killing off this chain. Allowing thieves to attack crypto coins and profit from it is unjust and immoral. If you feel like it I think discussing this in public might also be a good idea.
Thanks.
Lolcust:
Quote from: OneMINER on Today at 09:52:44 PM
I respect your opinion but frankly that's ridiculous. Fracturing net? So fractured that traffic doesn't get rerouted? I think not. Also if a person edited the faulty software so that it was compatible with the newer software why would the program try to start a new chain again? If it can communicate with other nodes it would download the chain and hash at it like a normal miner. The fact that it orphaned blocks is proof that it communicates with other nodes.
Um, well yeah, fracturing is not likely. A "bigger" (in the "more work" sense) chain with same pcharstarts being built during the time that you were re-launching ? Not entirely unlikely.
Did you change the pchar-thingies?
Quote from: OneMINER on Today at 09:52:44 PM
I ask you to reconsider your comments and if you so choose to throw your weight at killing off this chain.
Well, best course of action is to analyze the affected chain. I think we should contact Theymos (theymos is known to have a blockchain-analysis hobby)
Also, I didn't quite get the "throw weight to kill it off" part... whom must I kill ?
Quote from: OneMINER on Today at 09:52:44 PM
Allowing thieves to attack crypto coins and profit from it is unjust and immoral. If you feel like it I think discussing this in public might also be a good idea.
Well, assuming it was indeed a 51-er theft, the attacker has so far failed to generate a profit since no exchange accepts fairbrix.
And discussing it in public is quite a good idea, IMHO. I think you can post this exchange in a thread of your choice (maybe a new one, since this is an interesting and distinct incident) and we can continue from there.
*Edit* If you have an opinion on the matter please post it but keep it on topic. Please ignore and do not comment on the posts that have nothing to do with fairbirx, 51% attacks or other such things. Thank you.