04:18:26 <m-relay> <l​eonarth_:matrix.org> Selfish mining / block withholding
04:18:27 <m-relay> <l​eonarth_:matrix.org> My understanding of how this attack vector works:
04:18:29 <m-relay> <l​eonarth_:matrix.org> - PoolX mines block 3000: doesn't broadcast it to the network
04:18:31 <m-relay> <l​eonarth_:matrix.org> - PoolX starts mining block 3001 while other pools are still doing useless work on block 3000
04:18:33 <m-relay> <l​eonarth_:matrix.org> - PoolY mines block 3000 and broadcasts it
04:18:35 <m-relay> <l​eonarth_:matrix.org> - PoolX mines block 3001 and immediately broadcasts both 3000,3001 blocks to the network creating a longer chain
04:18:37 <m-relay> <l​eonarth_:matrix.org> - PoolY block becomes orphaned as PoolX is ahead
04:18:39 <m-relay> <l​eonarth_:matrix.org> - PoolX gets reward from 2 blocks
04:18:41 <m-relay> <l​eonarth_:matrix.org> Countermeasures: we could design pattern recognition for this type of behavior and discard PoolX broadcast, e.g.: if the block broadcast time of block 3000 and block 3001 are too close then PoolX is mining too fast.
04:18:43 <m-relay> <l​eonarth_:matrix.org> Meaning PoolX is either:
04:18:45 <m-relay> <l​eonarth_:matrix.org> - mining too fast: achieved over 51% of network hashrate