From: "Luke-Jr" <luke@dashjr.org>
To: Pieter Wuille <pieter.wuille@gmail.com>
Date: Sun, 14 Jul 2013 20:16:41 +0000
User-Agent: KMail/1.13.7 (Linux/3.7.10-gentoo; KDE/4.10.4; x86_64; ; )
References: <20130705140140.GA23949@netbook.cypherspace.org>
	<201307141933.13754.luke@dashjr.org>
	<20130714194205.GA27202@vps7135.xlshosting.net>
In-Reply-To: <20130714194205.GA27202@vps7135.xlshosting.net>
MIME-Version: 1.0
Content-Type: multipart/signed; boundary="nextPart8338126.cSS8d676eV";
	protocol="application/pgp-signature"; micalg=pgp-sha256
Content-Transfer-Encoding: 7bit
Message-Id: <201307142016.48605.luke@dashjr.org>
Cc: bitcoin-development@lists.sourceforge.net, Jorge@vps7135.xlshosting.net
Subject: Re: [Bitcoin-development] libzerocoin released,
	what about a zerocoin-only alt-coin with either-or mining
Precedence: list

--nextPart8338126.cSS8d676eV
Content-Type: Text/Plain;
  charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable

On Sunday, July 14, 2013 7:42:06 PM Pieter Wuille wrote:
> On Sun, Jul 14, 2013 at 07:33:06PM +0000, Luke-Jr wrote:
> > > The issue is that unless there is a cost to mining a *invalid* block
> > > the merge mined coin has little protection from miners who mine inval=
id
> > > blocks, either maliciously or through negligence. If the coin isn't
> > > worth much, either because it's market value is low or the worth is
> > > negative to the malicious miner, your theories of value have nothing
> > > to do with the issue.
> >=20
> > Invalid blocks are rejected by validating clients in all circumstances.
>=20
> I don't think that's what John means.
>=20
> If you have hash power for the parent chain, mining invalid blocks for the
> merge-mined chain costs you nothing. Yes, they will be invalid, but you've
> lost nothing.

Nor gained anything. So the "lesser" chain maybe can't trust SPV.
But trusting SPV was already a bad idea anyway.

Note that the parent chain is not in any privileged position here either: a=
=20
merged-mined chain could provide the value to the miner he is interested in=
,=20
while he sees nothing of the parent chain. In short, merged mining is prett=
y=20
much unavoidable in any case.

> The basic assumption underlying mining security is that it is more
> profitable to collaborate with mining a chain (and profit from the block
> payout) than to attack it. In the case of merged mining, this assumption
> is not valid.

The basic assumption of SPV is that more people will be assisting rather th=
an=20
making invalid blocks. That motive doesn't necessarily need to be economic,=
=20
nor do proper validating clients rely on it. The only real assumption behin=
d=20
mining is that the majority will not be aiming to reverse transactions with=
=20
valid blocks.

P.S. How about a Zerocoin with no-reward/PoSacrifice merged mining as well =
as=20
(rewarded) Prime POW; maybe with no subsidy halving, to try a new economic=
=20
idea as well ;)

--nextPart8338126.cSS8d676eV
Content-Type: application/pgp-signature; name=signature.asc 
Content-Description: This is a digitally signed message part.

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2.0.20 (GNU/Linux)
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=
=2Jvs
-----END PGP SIGNATURE-----

--nextPart8338126.cSS8d676eV--