A technical point about SIGHASH_NOINPUT: It seems like a more general and
technically simpler to implement idea would be to have a boolean specifying
whether the inputs listed must be all of them (the way it works normally)
or a subset of everything. It feels like a similar boolean should be made
for outputs as well. Or maybe a single boolean should apply to both. In any
case, one could always use SIGHASH_SUBSET and not specify any inputs and
that would have the same effect as SIGHASH_NOINPUT.

On Mon, May 7, 2018 at 12:40 PM, Christian Decker via bitcoin-dev <
bitcoin-dev@lists.linuxfoundation.org> wrote:

> Given the general enthusiasm, and lack of major criticism, for the
> `SIGHASH_NOINPUT` proposal, I'd like to formally ask the BBEs (benevolent
> BIP editors) to be assigned a BIP number. I have hacked together a
> simple implementation of the hashing implementation in Bitcoin Core [1]
> though I think it's unlikely to sail through review, and given the lack
> of ground-work on witness V1 scripts, I can't really test it now, and
> only the second commit is part of the implementation itself.
>
> One issue that was raised off list was that some fork coins have used
> sighash 0x40 as FORKID. This does not conflict with this proposal since
> the proposal only applies to segwit transactions, which the fork coins
> have explicitly disabled :-)
>
> I'm looking forward to discussing how to we can move forward to
> implementing this proposal, and how we can combine multiple proposals
> into the next soft-fork.
>
> Cheers,
> Christian
>
> [1] https://github.com/cdecker/bitcoin/tree/noinput
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