From: Johnson Lau <jl2012@xbt.hk>
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Date: Thu, 10 May 2018 01:56:46 +0800
References: <87po25lmzs.fsf@rustcorp.com.au>
To: Rusty Russell <rusty@rustcorp.com.au>,
	bitcoin-dev <bitcoin-dev@lists.linuxfoundation.org>
In-Reply-To: <87po25lmzs.fsf@rustcorp.com.au>
Message-Id: <F8C553EE-9AF5-4348-90B7-3EC55FC46B4C@xbt.hk>
Subject: Re: [bitcoin-dev] Making OP_TRUE standard?
Precedence: list

You should make a =E2=80=9C0 fee tx with exactly one OP_TRUE output=E2=80=9D=
 standard, but nothing else. This makes sure CPFP will always be needed, =
so the OP_TRUE output won=E2=80=99t pollute the UTXO set

Instead, would you consider to use ANYONECANPAY to sign the tx, so it is =
possible add more inputs for fees? The total tx size is bigger than the =
OP_TRUE approach, but you don=E2=80=99t need to ask for any protocol =
change.

In long-term, I think the right way is to have a more flexible SIGHASH =
system to allow people to add more inputs and outputs easily.


> On 9 May 2018, at 7:57 AM, Rusty Russell via bitcoin-dev =
<bitcoin-dev@lists.linuxfoundation.org> wrote:
>=20
> Hi all,
>=20
>        The largest problem we are having today with the lightning
> protocol is trying to predict future fees.  Eltoo solves this =
elegantly,
> but meanwhile we would like to include a 546 satoshi OP_TRUE output in
> commitment transactions so that we use minimal fees and then use CPFP
> (which can't be done at the moment due to CSV delays on outputs).
>=20
> Unfortunately, we'd have to P2SH it at the moment as a raw 'OP_TRUE' =
is
> non-standard.  Are there any reasons not to suggest such a policy
> change?
>=20
> Thanks!
> Rusty.
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