That conversation missed a second issue. Namely that there is no way to punish people if there is a double spend in a micro block that happens in key block which reorg'd away the first transaction. eg one miner mines a transaction in a micro block, another miner (either by not having seen the first yet, or being malicious - potentially the same miner) mines a key block which reorgs away the first micro block and then, in their first micro block, mines a double spend. This can happen at any time, so you end up having to fall back to regular full blocks for confirmation times :(. Also, Greg Slepak brought up a good point on twitter at https://twitter.com/taoeffect/status/654358023138209792. Noting that this model means users could no longer pick transactions in a mining pool which was set up in such a way (it could be tweaked to do so with separate rewards and pubkeys, but now the user can commit fraud at a much lower cost - their own pool reward, not the block's total reward). On October 14, 2015 11:28:51 AM PDT, Ittay via bitcoin-dev wrote: >On Wed, Oct 14, 2015 at 2:12 PM, Bryan Bishop >wrote: > >> On Wed, Oct 14, 2015 at 1:02 PM, Emin Gün Sirer >> wrote: >> > while the whitepaper has all the nitty gritty details: >> > http://arxiv.org/abs/1510.02037 >> >> Taking reward compensation back by fraud proofs is not enough to fix >> the problems associated with double spending (such as, everyone has >to >> wait for the "real" confirmations instead of the "possibly >> double-spend" confirmations). Some of this was discussed in -wizards >> recently: >> http://gnusha.org/bitcoin-wizards/2015-09-19.log > > >Fraud proof removes all the attacker's revenue. It's like the attacker >sacrifices an entire block for double spending in the current system. I >think Luke-Jr got it right at that discussion. > >Best, >Ittay > > >------------------------------------------------------------------------ > >_______________________________________________ >bitcoin-dev mailing list >bitcoin-dev@lists.linuxfoundation.org >https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev