From: Luke Dashjr <luke@dashjr.org>
To: Johnson Lau <jl2012@xbt.hk>
Date: Wed, 26 Apr 2017 20:01:10 +0000
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Cc: bitcoin-dev <bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] Segwit v2
Precedence: list

On Wednesday 26 April 2017 7:31:38 PM Johnson Lau wrote:
> I prefer not to do anything that requires pools software upgrade or wallet
> upgrade. So I prefer to keep the dummy marker, and not change the
> commitment structure as suggested by another post.

=46air enough, I guess. Although I think the dummy marker could actually be=
 non-
consensus critical so long as the hashing replaces it with a 0.

> For your second suggestion, I think we should keep scriptSig empty as that
> should be obsoleted. If you want to put something in scriptSig, you should
> put it in witness instead.

There are things scriptSig can do that witness cannot today - specifically =
add=20
additional conditions under the signature. We can always obsolete scriptSig=
=20
later, after segwit has provided an alternative way to do this.

> Maybe we could restrict witness to IsPushOnly() scriptPubKey, so miners
> can=E2=80=99t put garbage to legacy txs.

They already can malleate transactions and add garbage to the blocks. I don=
't=20
see the benefit here.

Luke