On Fri, Oct 3, 2014 at 7:28 AM, Matt Whitlock <b...@mattwhitlock.name> wrote: > Is there a reason why we can't have the new opcode simply replace the top > stack item with the block height of the txout being redeemed?
This would not be soft-forking compatible. It also would be unsafe in that it would result in transactions which once mined could not be restored in a reorg through no fault of the participants, which makes the coins less fungible and differently safe to accept. It risks creating weird pressures around immediate block admission since a one additional block delay could forever censor such a transaction (E.g. increases the power of single miners to censor or steal). Avoiding this is a conscious decision in Bitcoin and also part of the justification for the 100 block maturity of newly generated coins. It also would require violating the script/transaction/block layering more substantially, complicating implementations, and making the validity of a script no longer a deterministic pure function of the transaction. Avoiding these issues is a conscious design in OP_CHECKLOCKTIMEVERIFY. I would strenuously oppose a proposal which failed in any of these respects. > Then arbitrary logic could be implemented, including "output cannot be spent > until a certain time" and also "output can ONLY be spent until a certain > time," as well as complex logic with alternative key groups with differing > time constraints. You can already achieve the not spendable after logic with a cancellation spend that moves the coin in the usual way. (Which doesn't even require the participant be online, with the help of some network service to queue unlocked transactions). > OP_CHECKLOCKTIMEVERIFY, as conceived, seems too limited, IMHO. It is intentionally so, and yet it covers the intended use cases; including ones with alternative key groups, they are just not exclusive. ------------------------------------------------------------------------------ Meet PCI DSS 3.0 Compliance Requirements with EventLog Analyzer Achieve PCI DSS 3.0 Compliant Status with Out-of-the-box PCI DSS Reports Are you Audit-Ready for PCI DSS 3.0 Compliance? Download White paper Comply to PCI DSS 3.0 Requirement 10 and 11.5 with EventLog Analyzer http://pubads.g.doubleclick.net/gampad/clk?id=154622311&iu=/4140/ostg.clktrk _______________________________________________ Bitcoin-development mailing list Bitcoinemail@example.com https://lists.sourceforge.net/lists/listinfo/bitcoin-development