📅 Original date posted:2019-05-27
📝 Original message:On Sun, May 26, 2019 at 5:07 PM Aymeric Vitte via bitcoin-dev <
bitcoin-dev at lists.linuxfoundation.org> wrote:
> I realized recently that my segwit implementation was not correct,
> basically some time ago, wrongly reading the specs (and misleaded by
> what follows), I thought that scriptsig would go into witness data as it
> was, but that's not the case, op_pushdata is replaced by varlen
>
> Now reading correctly the specs, they seem to be not totally correct,
> then the first question is: why OP_0 is 00 in witness data and not 0100?
> Does this apply to other op_codes? This does not look logical at all
>
>
op_pushdata allows for unsigned integers and thus it uses the extra byte to
specify that.
A varint (varlen) is unsigned. 0 and anything <= 252 is one byte length,
so 00.
> The second question is: why for non segwit inputs there is a 00 length
> in segwit data, what is the rational for that? It should just be nothing
> since you don't need this to reconciliate things
>
>
Because you don't have the number of witnesses as you have for
inputs/outputs. The witness data length is assumed to be the same as the
inputs length. And then for non-segwit inputs you need the 00 to specify
that it is empty.
Hope that helps.
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Kostas Karasavvas [ARCHIVE] /
npub1tq…y3e9m
2023-06-07 20:18:23
in reply to nevent1q…vxed
Author Public Key
npub1tqac06nxg94veg9atxfktrfdwpl2a4snw2xdrt52ek5893jnnkkqey3e9mPublished at
2023-06-07 20:18:23Event JSON
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"content": "📅 Original date posted:2019-05-27\n📝 Original message:On Sun, May 26, 2019 at 5:07 PM Aymeric Vitte via bitcoin-dev \u003c\nbitcoin-dev at lists.linuxfoundation.org\u003e wrote:\n\n\u003e I realized recently that my segwit implementation was not correct,\n\u003e basically some time ago, wrongly reading the specs (and misleaded by\n\u003e what follows), I thought that scriptsig would go into witness data as it\n\u003e was, but that's not the case, op_pushdata is replaced by varlen\n\u003e\n\u003e Now reading correctly the specs, they seem to be not totally correct,\n\u003e then the first question is: why OP_0 is 00 in witness data and not 0100?\n\u003e Does this apply to other op_codes? This does not look logical at all\n\u003e\n\u003e\nop_pushdata allows for unsigned integers and thus it uses the extra byte to\nspecify that.\n\nA varint (varlen) is unsigned. 0 and anything \u003c= 252 is one byte length,\nso 00.\n\n\n\u003e The second question is: why for non segwit inputs there is a 00 length\n\u003e in segwit data, what is the rational for that? It should just be nothing\n\u003e since you don't need this to reconciliate things\n\u003e\n\u003e\nBecause you don't have the number of witnesses as you have for\ninputs/outputs. The witness data length is assumed to be the same as the\ninputs length. And then for non-segwit inputs you need the 00 to specify\nthat it is empty.\n\nHope that helps.\n-------------- next part --------------\nAn HTML attachment was scrubbed...\nURL: \u003chttp://lists.linuxfoundation.org/pipermail/bitcoin-dev/attachments/20190527/b1ee6569/attachment.html\u003e",
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