Re: [bitcoin-dev] OP_CODESEPARATOR Re: BIP Proposal: The Great Consensus Cleanup

From: Dustin Dettmer <dustinpaystaxes@gmail•com>
To: Bitcoin Protocol Discussion <bitcoin-dev@lists•linuxfoundation.org>
Subject: Re: [bitcoin-dev] OP_CODESEPARATOR Re: BIP Proposal: The Great Consensus Cleanup
Date: Sun, 10 Mar 2019 11:28:25 -0700	[thread overview]
Message-ID: <CABLeJxS1sK8x-dgkOJ5f4=vjB4xja6EVeca-aHbeqOyS7SwWWQ@mail.gmail.com> (raw)
In-Reply-To: <PS2P216MB0179EEBB4E8EBF86EB25EACD9D4F0@PS2P216MB0179.KORP216.PROD.OUTLOOK.COM>

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What about putting it in a deprecated state for some time. Adjust the
transaction weight so using the op code is more expensive (10x, 20x?) and
get the word out that it will be removed in the future.

You could even have nodes send a reject code with the message
“OP_CODESEPARATOR is depcrecated.”

On Sun, Mar 10, 2019 at 7:55 AM LORD HIS EXCELLENCY JAMES HRMH via
bitcoin-dev <bitcoin-dev@lists•linuxfoundation.org> wrote:

>
> Opinion: Lock in a blockheight to get rid of it 10 years in the future.
> Use it as press that Bitcoin is going to lose $1,000,000 if some mystery
> person does not put their transaction through by then, try for global
> presses. Use the opportunity to get rid of it while you are able. Once
> gazetted anything is public knowledge.
>
> Regards,
> LORD HIS EXCELLENCY JAMES HRMH
>
> ------------------------------
> *From:* bitcoin-dev-bounces@lists•linuxfoundation.org <
> bitcoin-dev-bounces@lists•linuxfoundation.org> on behalf of Matt Corallo
> via bitcoin-dev <bitcoin-dev@lists•linuxfoundation.org>
> *Sent:* Saturday, 9 March 2019 7:14 AM
> *To:* Sjors Provoost
> *Cc:* Bitcoin Protocol Discussion
> *Subject:* Re: [bitcoin-dev] OP_CODESEPARATOR Re: BIP Proposal: The Great
> Consensus Cleanup
>
> Aside from the complexity issues here, note that for a user to be
> adversely affect, they probably have to have pre-signed lock-timed
> transactions. Otherwise, in the crazy case that such a user exists, they
> should have no problem claiming the funds before activation of a soft-fork
> (and just switching to the swgwit equivalent, or some other equivalent
> scheme). Thus, adding additional restrictions like tx size limits will
> equally break txn.
>
> > On Mar 8, 2019, at 14:12, Sjors Provoost <sjors@sprovoost•nl> wrote:
> >
> >
> >> (1) It has been well documented again and again that there is desire to
> remove OP_CODESEPARATOR, (2) it is well-documented OP_CODESEPARATOR in
> non-segwit scripts represents a rather significant vulnerability in Bitcoin
> today, and (3) lots of effort has gone into attempting to find practical
> use-cases for OP_CODESEPARATOR's specific construction, with no successes
> as of yet. I strongly, strongly disagree that the highly-unlikely remote
> possibility that someone created something before which could be rendered
> unspendable is sufficient reason to not fix a vulnerability in Bitcoin
> today.
> >>
> >>> I suggest an alternative whereby the execution of OP_CODESEPARATOR
> increases the transactions weight suitably as to temper the vulnerability
> caused by it.  Alternatively there could be some sort of limit (maybe 1) on
> the maximum number of OP_CODESEPARATORs allowed to be executed per script,
> but that would require an argument as to why exceeding that limit isn't
> reasonable.
> >>
> >> You could equally argue, however, that any such limit could render some
> moderately-large transaction unspendable, so I'm somewhat skeptical of this
> argument. Note that OP_CODESEPARATOR is non-standard, so getting them mined
> is rather difficult in any case.
> >
> > Although I'm not a fan of extra complicity, just to explore these two
> ideas a bit further.
> >
> > What if such a transaction:
> >
> > 1. must have one input; and
> > 2. must be smaller than 400 vbytes; and
> > 3. must spend from a UTXO older than fork activation
> >
> > Adding such a contextual check seems rather painful, perhaps comparable
> to nLockTime. Anything more specific than the above, e.g. counting the
> number of OP_CODESEPARATOR calls, seems like guess work.
> >
> > Transaction weight currently doesn't consider OP codes, it only
> considers if bytes are part of the witness. Changing that to something more
> akin to Ethereums gas pricing sounds too complicated to even consider.
> >
> >
> > I would also like to believe that whoever went through the trouble of
> using OP_CODESEPARATOR reads this list.
> >
> > Sjors
> >
>
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