From: Kostas Karasavvas <kkarasavvas@gmail•com>
To: Aymeric Vitte <vitteaymeric@gmail•com>,
Bitcoin Protocol Discussion
<bitcoin-dev@lists•linuxfoundation.org>
Subject: Re: [bitcoin-dev] Two questions about segwit implementation
Date: Mon, 27 May 2019 10:26:21 +0300 [thread overview]
Message-ID: <CABE6yHsCf7Mz+wDq7wPUR3YT0ua2i4O20XjF1-GZD_zJ8BXkVQ@mail.gmail.com> (raw)
In-Reply-To: <e537e781-e10f-7299-fddb-67fab74124c0@gmail.com>
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On Sun, May 26, 2019 at 5:07 PM Aymeric Vitte via bitcoin-dev <
bitcoin-dev@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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prev parent reply other threads:[~2019-05-27 7:26 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-25 23:56 Aymeric Vitte
2019-05-26 14:33 ` Johnson Lau
2019-05-26 16:18 ` Aymeric Vitte
2019-05-26 16:28 ` Johnson Lau
2019-05-26 17:09 ` Aymeric Vitte
2019-05-26 17:24 ` Johnson Lau
2019-05-26 21:17 ` Aymeric Vitte
2019-05-26 17:54 ` Pieter Wuille
2019-05-26 19:34 ` Thomas Kerin
2019-05-27 7:26 ` Kostas Karasavvas [this message]
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