Date: Sun, 14 Jul 2013 21:42:06 +0200
From: Pieter Wuille <pieter.wuille@gmail.com>
To: Luke-Jr <luke@dashjr.org>
Message-ID: <20130714194205.GA27202@vps7135.xlshosting.net>
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	<201307141933.13754.luke@dashjr.org>
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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

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 invalid
> > 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.
> 
> Invalid blocks are rejected by validating clients in all circumstances.

I don't think that's what John means.

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.

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.

-- 
Pieter