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From: Jeremy <jlrubin@mit.edu>
To: Jeremy <jlrubin@mit.edu>
Cc: Bitcoin development mailing list <bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] Note on Sequence Lock Upgrades Defect
Date: Sat, 4 Sep 2021 20:19:57 -0700	[thread overview]
Message-ID: <CAD5xwhjrcTMSkikYFaNmMJeAhmR2cwTEbt7G80-G9Xj3vNnbrA@mail.gmail.com> (raw)
In-Reply-To: <CAD5xwhiKU1fuhqmKsx28f1nuw9CmvbyrS=BtM4X-L+WPgWY3Wg@mail.gmail.com>

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In working on resolving this issue, one issue that has come up is what
sequence values get used by wallet implementations?

E.g., in Bitcoin Core a script test says

BIP125_SEQUENCE_NUMBER = 0xfffffffd  # Sequence number that is rbf-opt-in
(BIP 125) and csv-opt-out (BIP 68)

Are any other numbers currently expected by any wallet software to be
broadcastable with the DISABLE flag set? Does anyone use *this* number? Is
there any advantage of this number v.s. just 0? Do people commonly use
0xfffffffd? 0xfffffffe is special, but it seems the former has the
alternative of either 0 valued sequence lock (1<<22 or 0).

Are there any other sequence numbers that are not defined in a BIP that
might be used somewhere?

Cheers,

Jeremy
--
@JeremyRubin <https://twitter.com/JeremyRubin>
<https://twitter.com/JeremyRubin>


On Fri, Sep 3, 2021 at 8:32 PM Jeremy <jlrubin@mit.edu> wrote:

> Hi Bitcoin Devs,
>
> I recently noticed a flaw in the Sequence lock implementation with respect
> to upgradability. It might be the case that this is protected against by
> some transaction level policy (didn't see any in policy.cpp, but if not,
> I've put up a blogpost explaining the defect and patching it
> https://rubin.io/bitcoin/2021/09/03/upgradable-nops-flaw/
>
> I've proposed patching it here
> https://github.com/bitcoin/bitcoin/pull/22871, it is proper to widely
> survey the community before patching to ensure no one is depending on the
> current semantics in any live application lest this tightening of
> standardness rules engender a confiscatory effect.
>
> Best,
>
> Jeremy
>
> --
> @JeremyRubin <https://twitter.com/JeremyRubin>
> <https://twitter.com/JeremyRubin>
>

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  reply	other threads:[~2021-09-05  3:20 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-04  3:32 [bitcoin-dev] Note on Sequence Lock Upgrades Defect Jeremy
2021-09-05  3:19 ` Jeremy [this message]
2021-09-06  2:35 ` David A. Harding
2021-09-06  3:17   ` Jeremy
2021-09-06  6:16     ` darosior
2021-09-09  0:02 ` Antoine Riard
2021-09-09  1:04   ` Jeremy

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