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From: Johnson Lau <jl2012@xbt.hk>
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To: Aymeric Vitte <vitteaymeric@gmail.com>
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Cc: bitcoin-dev <bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] Two questions about segwit implementation
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This is not how it works. While the transaction creator may know which =
inputs are segwit, the validators have no way to tell until they look up =
the UTXO set.
In a transaction, all information about an input the validators have is =
the 36-byte outpoint (txid + index). Just by looking at the outpoint, =
there is no way to tell whether it is segwit-enabled or not. So there =
needs to be a way to tell the validator that =E2=80=9Cthe witness for =
this input is empty=E2=80=9D, and it is the =E2=80=9C00=E2=80=9D.
> On 27 May 2019, at 12:18 AM, Aymeric Vitte <vitteaymeric@gmail.com> =
wrote:
>=20
> =E2=80=A6=E2=80=A6. for the 00 number of witness
> data for non segwit inputs the one that is doing the transaction knows
> which inputs are segwit or not, then parsing the transaction you can
> associate the correct input to the correct witness data, without the
> need of 00, so I must be missing the use case
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