rich1.0npub1m230cem2yh3mtdzkg32qhj73uytgkyg5ylxsu083n3tpjnajxx4qqa2np2https://nostr.ae/npub1m230cem2yh3mtdzkg32qhj73uytgkyg5ylxsu083n3tpjnajxx4qqa2np2njumphttps://nostr.ae📅 Original date posted:2015-12-19 📝 Original message: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 -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 650 bytes Desc: Digital signature URL: <http://lists.linuxfoundation.org/pipermail/bitcoin-dev/attachments/20151219/8c0d100a/attachment.sig>