📅 Original date posted:2016-08-16
📝 Original message:On Tue, Aug 16, 2016 at 3:43 PM, Peter Todd via bitcoin-dev <
bitcoin-dev at lists.linuxfoundation.org> wrote:
> On Tue, Aug 16, 2016 at 07:37:19PM +0000, Luke Dashjr via bitcoin-dev
> wrote:
> > On Tuesday, August 16, 2016 5:53:08 PM Johnson Lau via bitcoin-dev wrote:
> > > A new BIP is prepared to deal with OP_IF and OP_NOTIF malleability in
> > > P2WSH:
> > > https://github.com/jl2012/bips/blob/minimalif/bip-minimalif.mediawiki
> > > https://github.com/bitcoin/bitcoin/pull/8526
> >
> > I am not sure this makes sense. SegWit transactions are already
> non-malleable
> > due to skipping the witness data in calculating the transaction id. What
> is
> > the benefit to this?
>
> SegWit txids aren't malleable, but segwit transactions as a whole still
> are.
> For instance, I could mess with a segwit transaction by replacing part of
> the
> witness that is used as an argument to an OP_IF with a much larger push,
> potentially making the transaction larger, thus making it not get mined
> due to
> the higher fee. There are also potential legal issues if someone replaces a
> push with data where posession in your jurisdiction is illegal.
>
If one's goal is to mess with an transaction to prevent it from being
mined, it is more effective to just not relay the transaction rather than
to mess with the witness. Given two transactions with the same txid and
different witness data, miners and good nodes ought to mine/relay the
version with the lower cost (smaller?) witness data.
Worries about "illegal data" appearing in the blockchain is not an issue
worth writing a soft-fork over.
There may be good reasons for this BIP, but I don't think the reasons give
above are good.
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Russell O'Connor [ARCHIVE] /
npub1dw…8plrw
2023-06-07 17:52:56
in reply to nevent1q…ergv
Author Public Key
npub1dw88wd5gqsqn6ufxhf9h03uk8087l7gfzdtez5csjlt6pupu4pwsj8plrwPublished at
2023-06-07 17:52:56Event JSON
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"content": "📅 Original date posted:2016-08-16\n📝 Original message:On Tue, Aug 16, 2016 at 3:43 PM, Peter Todd via bitcoin-dev \u003c\nbitcoin-dev at lists.linuxfoundation.org\u003e wrote:\n\n\u003e On Tue, Aug 16, 2016 at 07:37:19PM +0000, Luke Dashjr via bitcoin-dev\n\u003e wrote:\n\u003e \u003e On Tuesday, August 16, 2016 5:53:08 PM Johnson Lau via bitcoin-dev wrote:\n\u003e \u003e \u003e A new BIP is prepared to deal with OP_IF and OP_NOTIF malleability in\n\u003e \u003e \u003e P2WSH:\n\u003e \u003e \u003e https://github.com/jl2012/bips/blob/minimalif/bip-minimalif.mediawiki\n\u003e \u003e \u003e https://github.com/bitcoin/bitcoin/pull/8526\n\u003e \u003e\n\u003e \u003e I am not sure this makes sense. SegWit transactions are already\n\u003e non-malleable\n\u003e \u003e due to skipping the witness data in calculating the transaction id. What\n\u003e is\n\u003e \u003e the benefit to this?\n\u003e\n\u003e SegWit txids aren't malleable, but segwit transactions as a whole still\n\u003e are.\n\u003e For instance, I could mess with a segwit transaction by replacing part of\n\u003e the\n\u003e witness that is used as an argument to an OP_IF with a much larger push,\n\u003e potentially making the transaction larger, thus making it not get mined\n\u003e due to\n\u003e the higher fee. There are also potential legal issues if someone replaces a\n\u003e push with data where posession in your jurisdiction is illegal.\n\u003e\n\nIf one's goal is to mess with an transaction to prevent it from being\nmined, it is more effective to just not relay the transaction rather than\nto mess with the witness. Given two transactions with the same txid and\ndifferent witness data, miners and good nodes ought to mine/relay the\nversion with the lower cost (smaller?) witness data.\n\nWorries about \"illegal data\" appearing in the blockchain is not an issue\nworth writing a soft-fork over.\n\nThere may be good reasons for this BIP, but I don't think the reasons give\nabove are good.\n-------------- next part --------------\nAn HTML attachment was scrubbed...\nURL: \u003chttp://lists.linuxfoundation.org/pipermail/bitcoin-dev/attachments/20160816/06d324f7/attachment.html\u003e",
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