Received: from sog-mx-4.v43.ch3.sourceforge.com ([172.29.43.194] helo=mx.sourceforge.net) by sfs-ml-3.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1UySBR-0003uQ-9B for bitcoin-development@lists.sourceforge.net; Sun, 14 Jul 2013 19:42:13 +0000 X-ACL-Warn: Received: from vps7135.xlshosting.net ([178.18.90.41]) by sog-mx-4.v43.ch3.sourceforge.com with esmtp (Exim 4.76) id 1UySBP-0001rt-IM for bitcoin-development@lists.sourceforge.net; Sun, 14 Jul 2013 19:42:13 +0000 Received: by vps7135.xlshosting.net (Postfix, from userid 1000) id 1EF6C33CB93; Sun, 14 Jul 2013 21:42:06 +0200 (CEST) Date: Sun, 14 Jul 2013 21:42:06 +0200 From: Pieter Wuille To: Luke-Jr Message-ID: <20130714194205.GA27202@vps7135.xlshosting.net> References: <20130705140140.GA23949@netbook.cypherspace.org> <201307141933.13754.luke@dashjr.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201307141933.13754.luke@dashjr.org> X-PGP-Key: http://sipa.ulyssis.org/pubkey.asc User-Agent: Mutt/1.5.21 (2010-09-15) X-Spam-Score: 0.8 (/) X-Spam-Report: Spam Filtering performed by mx.sourceforge.net. See http://spamassassin.org/tag/ for more details. 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (pieter.wuille[at]gmail.com) 0.0 DKIM_ADSP_CUSTOM_MED No valid author signature, adsp_override is CUSTOM_MED -0.4 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain 1.2 NML_ADSP_CUSTOM_MED ADSP custom_med hit, and not from a mailing list X-Headers-End: 1UySBP-0001rt-IM 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 X-BeenThere: bitcoin-development@lists.sourceforge.net X-Mailman-Version: 2.1.9 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 14 Jul 2013 19:42:13 -0000 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