Received: from sog-mx-2.v43.ch3.sourceforge.com ([172.29.43.192] helo=mx.sourceforge.net) by sfs-ml-2.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1UySLw-000381-Cm for bitcoin-development@lists.sourceforge.net; Sun, 14 Jul 2013 19:53:04 +0000 Received-SPF: pass (sog-mx-2.v43.ch3.sourceforge.com: domain of googlemail.com designates 209.85.215.175 as permitted sender) client-ip=209.85.215.175; envelope-from=john.dillon892@googlemail.com; helo=mail-ea0-f175.google.com; Received: from mail-ea0-f175.google.com ([209.85.215.175]) by sog-mx-2.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1UySLu-0007IU-J8 for bitcoin-development@lists.sourceforge.net; Sun, 14 Jul 2013 19:53:04 +0000 Received: by mail-ea0-f175.google.com with SMTP id z7so7242471eaf.6 for ; Sun, 14 Jul 2013 12:52:56 -0700 (PDT) MIME-Version: 1.0 X-Received: by 10.14.211.67 with SMTP id v43mr56230848eeo.55.1373831576267; Sun, 14 Jul 2013 12:52:56 -0700 (PDT) Received: by 10.223.12.131 with HTTP; Sun, 14 Jul 2013 12:52:56 -0700 (PDT) In-Reply-To: <20130714194205.GA27202@vps7135.xlshosting.net> References: <20130705140140.GA23949@netbook.cypherspace.org> <201307141933.13754.luke@dashjr.org> <20130714194205.GA27202@vps7135.xlshosting.net> Date: Sun, 14 Jul 2013 19:52:56 +0000 Message-ID: From: John Dillon To: Pieter Wuille Content-Type: text/plain; charset=ISO-8859-1 X-Spam-Score: -1.4 (-) X-Spam-Report: Spam Filtering performed by mx.sourceforge.net. See http://spamassassin.org/tag/ for more details. -1.5 SPF_CHECK_PASS SPF reports sender host as permitted sender for sender-domain 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (john.dillon892[at]googlemail.com) -0.0 SPF_PASS SPF: sender matches SPF record 0.2 FREEMAIL_ENVFROM_END_DIGIT Envelope-from freemail username ends in digit (john.dillon892[at]googlemail.com) -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature X-Headers-End: 1UySLu-0007IU-J8 Cc: Bitcoin Dev , 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 19:53:04 -0000 -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 On Sun, Jul 14, 2013 at 7:42 PM, Pieter Wuille wrote: > On Sun, Jul 14, 2013 at 07:33:06PM +0000, Luke-Jr wrote: >> 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. You said it better than I did. Essentially I am worried about the chain being strangled at birth, merge-mining makes doing so cost nothing for the attacker. With zerocoin this is a particularly dangerous possibility due to those in the Bitcoin community who would like to see Bitcoin continue to have poor privacy properties. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) iQEcBAEBCAAGBQJR4wF9AAoJEEWCsU4mNhiPtCgH/3QLvFer3QHNU7AP+nehwcgK QS3xLv60lvm+pYLVAp9xFyJ5SCHVGTPvWRBmoldk8xxh9ORHlNEsnrcx9ZONTJ4F ja4Alp9MLZK5S8dKk2juJNdKziyRkQci/nNwuqepX5JjCIRNZq1lcW4Be4W7InPt Ltrvp7lA03uNuAXxtlYnko4mEY5l1NiBp4BvhGZ6+GRdCltPeIk2m0NwLDHWd31t qFLnnPSw0/9FGVs7lOaWuxbMGwPzGrIu6TXm17dqgBsl+8JuP6zHFE1ccqIxKyb6 Tdf4yNvhsvE+qlTnmcQNxM9nMHL4uqBZqJR174fAKQzcNGzVLloqbmRqKzuw5o4= =leUJ -----END PGP SIGNATURE-----