Date: Tue, 16 May 2017 07:01:04 -0400
From: Peter Todd <pete@petertodd.org>
To: Gregory Maxwell <greg@xiph.org>
Message-ID: <20170516110104.GA5564@fedora-23-dvm>
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Cc: Bitcoin Dev <bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] Rolling UTXO set hashes
Precedence: list


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On Mon, May 15, 2017 at 11:59:58PM +0000, Gregory Maxwell via bitcoin-dev w=
rote:
> On Mon, May 15, 2017 at 11:04 PM, ZmnSCPxj via bitcoin-dev
> <bitcoin-dev@lists.linuxfoundation.org> wrote:
> > transactions is in the header, which would let lite nodes download a UT=
XO
> > set from any full node and verify it by verifying only block headers
> > starting from genesis.
>=20
> Ya, lite nodes with UTXO sets are one of the the oldest observed
> advantages of a commitment to the UTXO data:
>=20
> https://bitcointalk.org/index.php?topic=3D21995.0
>=20
> But it requires a commitment. And for most of the arguments for those
> you really want compact membership proofs.  The recent rise in
> interest in full block lite clients (for privacy reasons), perhaps
> complements the membership proofless usage.
>=20
> Pieter describes some uses for doing something like this without a
> commitment.  In my view, it's more interesting to first gain
> experience with an operation without committing to it (which is a
> consensus change and requires more care and consideration, which are
> easier if people have implementation experience).

To be clear, *none* of the previous (U)TXO commitment schemes require *mine=
rs*
to participate in generating a commitment. While that was previously though=
t to
be true by many, I've seen no counter-arguments to the argument I published=
 I
few months ago(1) that (U)TXO commitments did not require a soft-fork to
deploy.

1) "[bitcoin-dev] TXO commitments do not need a soft-fork to be useful",
   Peter Todd, Feb 23 2017,
   https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2017-February/01=
3591.html

--=20
https://petertodd.org 'peter'[:-1]@petertodd.org

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