The parameter used is property of the block just like the block height is a property and is already evaluated in scripts, so no new kind of dependency or encapsulation break. The transaction itself was not invalid in a re-org but evtl. others spending it if the difficulty on that fork is different, this is however intended as then on that fork the other was the winner. Tamas Blummer > On May 23, 2019, at 21:03, Jorge Timón wrote: > > The complains I could imagine about this, (apart from being a very > specific use case) are the same complains I heard about op_expiry. > Namely, that in a reorg, the same tx, having been valid in a given > block could potentially become invalid in some other block mining it. > I guess in this case the situation is less likely in this case than > with op_expiry, but it is still possible. > Another complain I could imagine is this kind of forces the > implementation to break some existing encapsulations, but I guess > those are just implementation details not that relevant here. > I personally don't have strong feelings towards this proposal one way > or the other, I'm just imagining what other people may complain about. > > On Thu, May 23, 2019 at 8:33 PM Tamas Blummer via bitcoin-dev > wrote: >> >> Difficulty change has profound impact on miner’s production thereby introduce the biggest risk while considering an investment. >> Commodity markets offer futures and options to hedge risks on traditional trading venues. Some might soon list difficulty futures. >> >> I think we could do much better than them natively within Bitcoin. >> >> A better solution could be a transaction that uses nLocktime denominated in block height, such that it is valid after the difficulty adjusted block in the future. >> A new OP_DIFFICULTY opcode would put onto stack the value of difficulty for the block the transaction is included into. >> The output script may then decide comparing that value with a strike which key can spend it. >> The input of the transaction would be a multi-sig escrow of those who entered the bet. >> The winner would broadcast. >> >> Once signed by both the transaction would not carry any counterparty risk and would not need an oracle to settle according to the bet. >> >> I plan to draft a BIP for this as I think this opcode would serve significant economic interest of Bitcoin economy, and is compatible with Bitcoin’s aim not to introduce 3rd party to do so. >> >> Do you see a fault in this proposal or want to contribute? >> >> Tamas Blummer >> >> _______________________________________________ >> bitcoin-dev mailing list >> bitcoin-dev@lists.linuxfoundation.org >> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev