📅 Original date posted:2016-08-16
📝 Original message: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.
Having said that, a better approach may be a separate CHECKBOOLVERIFY opcode
that fails unless the top item on the stack is a minimally encoded true or
false value, to allow script writers to opt into this behavior; it's not always
ideal.
--
https://petertodd.org 'peter'[:-1]@petertodd.org
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Peter Todd [ARCHIVE] /
npub1m2…a2np2
2023-06-07 17:52:55
in reply to nevent1q…ggh4
Author Public Key
npub1m230cem2yh3mtdzkg32qhj73uytgkyg5ylxsu083n3tpjnajxx4qqa2np2Published at
2023-06-07 17:52:55Event JSON
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"content": "📅 Original date posted:2016-08-16\n📝 Original message:On Tue, Aug 16, 2016 at 07:37:19PM +0000, Luke Dashjr via bitcoin-dev wrote:\n\u003e On Tuesday, August 16, 2016 5:53:08 PM Johnson Lau via bitcoin-dev wrote:\n\u003e \u003e A new BIP is prepared to deal with OP_IF and OP_NOTIF malleability in\n\u003e \u003e P2WSH:\n\u003e \u003e https://github.com/jl2012/bips/blob/minimalif/bip-minimalif.mediawiki\n\u003e \u003e https://github.com/bitcoin/bitcoin/pull/8526\n\u003e \n\u003e I am not sure this makes sense. SegWit transactions are already non-malleable \n\u003e due to skipping the witness data in calculating the transaction id. What is \n\u003e the benefit to this?\n\nSegWit txids aren't malleable, but segwit transactions as a whole still are.\nFor instance, I could mess with a segwit transaction by replacing part of the\nwitness that is used as an argument to an OP_IF with a much larger push,\npotentially making the transaction larger, thus making it not get mined due to\nthe higher fee. There are also potential legal issues if someone replaces a\npush with data where posession in your jurisdiction is illegal.\n\nHaving said that, a better approach may be a separate CHECKBOOLVERIFY opcode\nthat fails unless the top item on the stack is a minimally encoded true or\nfalse value, to allow script writers to opt into this behavior; it's not always\nideal.\n\n-- \nhttps://petertodd.org 'peter'[:-1]@petertodd.org\n-------------- next part --------------\nA non-text attachment was scrubbed...\nName: signature.asc\nType: application/pgp-signature\nSize: 455 bytes\nDesc: Digital signature\nURL: \u003chttp://lists.linuxfoundation.org/pipermail/bitcoin-dev/attachments/20160816/98322ba5/attachment.sig\u003e",
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