It's pretty obvious that Dave is suggesting an alternate tie-breaker: > It also makes an empty block far less attractive because it is easily > replaced, all the way until the next block locks it in.
I do see a problem with the proposal. Right now, when a miner sees a new block with the most work and there are no ties, it is always a good idea to build on top of it (unless they're in the middle of building a private chain, or other pathological cases). With this new heuristic (assuming it is actually followed by a good chunk of people), a miner can reasonably know whether or not they can safely mine a sibling of the block instead. When enough widely propagated transactions exist, and the block to orphan is small, there's minimal risk in mining a sibling block instead of a child block (the only extra risk is in someone else mining a child block right around the time we suceed in mining a siblish block, where we'll definitely be orphaned instead of ~50% of the time). Because the risk can be measured and is sometimes very small, it will then be profitable for a miner to orphan a small non-empty block and double-spend some confirmed transactions whenever the block confirming them is easily replaced. This lowers the security of 1-conf transactions. Mind you, that risk doesn't apply if we prefer non-empty blocks to empty blocks and leave it at that, or only switch if the new block doesn't double spend transactions in the old one, so it's a fixable issue. On 11 September 2015 at 12:32, Jorge Timón <bitcoin-dev@lists.linuxfoundation.org> wrote: > > On Sep 11, 2015 12:27 PM, "Dave Scotese via bitcoin-dev" > <bitcoin-dev@lists.linuxfoundation.org> wrote: >> >> Rather than (promising to, and when they don't actually, at least >> pretending to) use the first-seen block, I propose that a more sophisticated >> method of choosing which of two block solutions to accept. > > There's already a criterion to chose: the one with more work (in valid > blocks) on top of it. > > > _______________________________________________ > bitcoin-dev mailing list > bitcoin-dev@lists.linuxfoundation.org > https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev > _______________________________________________ bitcoin-dev mailing list bitcoin-dev@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
