From: Anthony Towns <aj@erisian.com.au>
To: Bitcoin Development Mailing List <bitcoindev@googlegroups.com>
Subject: Re: [bitcoindev] [BIP-0054] 64-Byte Transactions and Potential Legitimate Uses
Date: Sat, 2 May 2026 15:29:15 +1000 [thread overview]
Message-ID: <afWLq1DWaQPWLe45@erisian.com.au> (raw)
In-Reply-To: <123e5545-2eda-4eca-9532-4f4cea2b83ecn@googlegroups.com>
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 bitcoindev+unsubscribe@googlegroups.com.
To view this discussion visit https://groups.google.com/d/msgid/bitcoindev/afWLq1DWaQPWLe45%40erisian.com.au.
next prev parent reply other threads:[~2026-05-02 9:47 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-01 21:14 [bitcoindev] [BIP-0054] 64-Byte Transactions and Potential Legitimate Uses jeremy
2026-05-01 22:03 ` eric
2026-05-14 13:50 ` 'Antoine Poinsot' via Bitcoin Development Mailing List
2026-05-02 5:29 ` Anthony Towns [this message]
2026-05-02 15:26 ` Chris Stewart
2026-05-02 18:09 ` jeremy
2026-05-06 11:10 ` 'Antoine Poinsot' via Bitcoin Development Mailing List
2026-05-06 21:35 ` jeremy
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=afWLq1DWaQPWLe45@erisian.com.au \
--to=aj@erisian.com.au \
--cc=bitcoindev@googlegroups.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox