On Fri, May 01, 2026 at 02:14:35PM -0700, jeremy wrote: > *> 64-byte transactions can only contain a scriptPubKey that lets anyone > spend the funds, or one that burns them.* > This is not strictly correct. Here are a few examples of current and future > uses for 64-byte transactions: > > *Current Uses:* > - A transaction that donates to a future miner from a segwit (any version) > output via a spend to something like <512> OP_CSV (-> push2 bytes 512 csv > -> 0x02 0x00 0x02 0xb2) > - That same output which is used as a connector output for things that > should be claimed by a miner at a future time
This is an anyone can spend transaction. "Donation to a miner" and "anyone can spend" are synonyms. The script "OP_NOP <512> OP_CSV" would avoid the 64-byte special case if anyone were to want to do this. Note that these are not standard transactions and will generally not relay today. > - Pay-to-Anchor / ephemeral anchor outputs -- while typically p2a is for > txns you want to add a subsidy ability, a 64-byte txn could be used to shim > a keyed anchor to a p2a output after a certain delay. This only applies if you're donating an entire output to the miner, in order to accelerate / increase the effective feerate of the transaction that created that output. You would get a higher feerate by RBFing the original transaction to delete the output -- that is, rather than generating the transaction as "I'll have a feerate of X or X+Y, by signing two transactions, one creating an output, and one spending that output to miner fees (possibly with a timelock)", you do "I'll have a feerate of X or X+Y+Z, by signing two transactions, one at at feerate X, one at feerate X+Y+Z (possibly with a timelock)". If there's some case where the two transaction approach does become desirable, despite it's inefficiency, introducing an alternative 5-byte P2A scriptPubKey would only be a policy change. Cheers, aj -- You received this message because you are subscribed to the Google Groups "Bitcoin Development Mailing List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion visit https://groups.google.com/d/msgid/bitcoindev/afWLq1DWaQPWLe45%40erisian.com.au.
