Block witholding attacks are only possible if you have a majority of hashpower. If you only have 20% hashpower, you can't do this attack. Currently, this attack is only a theoretical attack, as the ones with all the hashpower today are not engaging in this behavior. Even if someone who had a lot of hashpower decided to pull off this attack, they wouldn't be able to disrupt much. Once that time comes, then I think this problem should be solved, until then it should be a low priority. There are more important things to work on in the meantime.
On 12/19/15, Peter Todd via bitcoin-dev <bitcoin-dev@lists.linuxfoundation.org> wrote: > At the recent Scaling Bitcoin conference in Hong Kong we had a chatham > house rules workshop session attending by representitives of a super > majority of the Bitcoin hashing power. > > One of the issues raised by the pools present was block withholding > attacks, which they said are a real issue for them. In particular, pools > are receiving legitimate threats by bad actors threatening to use block > withholding attacks against them. Pools offering their services to the > general public without anti-privacy Know-Your-Customer have little > defense against such attacks, which in turn is a threat to the > decentralization of hashing power: without pools only fairly large > hashing power installations are profitable as variance is a very real > business expense. P2Pool is often brought up as a replacement for pools, > but it itself is still relatively vulnerable to block withholding, and > in any case has many other vulnerabilities and technical issues that has > prevented widespread adoption of P2Pool. > > Fixing block withholding is relatively simple, but (so far) requires a > SPV-visible hardfork. (Luke-Jr's two-stage target mechanism) We should > do this hard-fork in conjunction with any blocksize increase, which will > have the desirable side effect of clearly show consent by the entire > ecosystem, SPV clients included. > > > Note that Ittay Eyal and Emin Gun Sirer have argued(1) that block > witholding attacks are a good thing, as in their model they can be used > by small pools against larger pools, disincentivising large pools. > However this argument is academic and not applicable to the real world, > as a much simpler defense against block withholding attacks is to use > anti-privacy KYC and the legal system combined with the variety of > withholding detection mechanisms only practical for large pools. > Equally, large hashing power installations - a dangerous thing for > decentralization - have no block withholding attack vulnerabilities. > > 1) http://hackingdistributed.com/2014/12/03/the-miners-dilemma/ > > -- > 'peter'[:-1]@petertodd.org > 00000000000000000188b6321da7feae60d74c7b0becbdab3b1a0bd57f10947d > _______________________________________________ bitcoin-dev mailing list bitcoin-dev@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
