From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sog-mx-3.v43.ch3.sourceforge.com ([172.29.43.193] helo=mx.sourceforge.net) by sfs-ml-2.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1YbWoS-0001MZ-72 for bitcoin-development@lists.sourceforge.net; Fri, 27 Mar 2015 16:08:48 +0000 X-ACL-Warn: Received: from resqmta-ch2-12v.sys.comcast.net ([69.252.207.44]) by sog-mx-3.v43.ch3.sourceforge.com with esmtps (TLSv1:AES128-SHA:128) (Exim 4.76) id 1YbWoR-0005t5-Ax for bitcoin-development@lists.sourceforge.net; Fri, 27 Mar 2015 16:08:48 +0000 Received: from resomta-ch2-01v.sys.comcast.net ([69.252.207.97]) by resqmta-ch2-12v.sys.comcast.net with comcast id 8g871q00326dK1R01g8iEo; Fri, 27 Mar 2015 16:08:42 +0000 Received: from crushinator.localnet ([IPv6:2601:6:4800:47f:1e4e:1f4d:332c:3bf6]) by resomta-ch2-01v.sys.comcast.net with comcast id 8g8h1q0072JF60R01g8hd7; Fri, 27 Mar 2015 16:08:41 +0000 From: Matt Whitlock To: bitcoin-development@lists.sourceforge.net Date: Fri, 27 Mar 2015 12:08:40 -0400 Message-ID: <1476737.qrsdQayLJV@crushinator> User-Agent: KMail/4.14.6 (Linux/3.18.7-gentoo; KDE/4.14.6; x86_64; ; ) In-Reply-To: <20150327155730.GB20754@amethyst.visucore.com> References: <55034205.4030607@localhost.local> <2210650.iUsfZECcCc@crushinator> <20150327155730.GB20754@amethyst.visucore.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Spam-Score: 0.0 (/) X-Spam-Report: Spam Filtering performed by mx.sourceforge.net. See http://spamassassin.org/tag/ for more details. -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [69.252.207.44 listed in list.dnswl.org] 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: 1YbWoR-0005t5-Ax Subject: Re: [Bitcoin-development] "network disruption as a service" and proof of local storage 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: Fri, 27 Mar 2015 16:08:48 -0000 On Friday, 27 March 2015, at 4:57 pm, Wladimir J. van der Laan wrote: > On Fri, Mar 27, 2015 at 11:16:43AM -0400, Matt Whitlock wrote: > > I agree that someone could do this, but why is that a problem? Isn't the goal of this exercise to ensure more full nodes on the network? In order to be able to answer the challenges, an entity would need to be running a full node somewhere. Thus, they have contributed at least one additional full node to the network. I could certainly see a case for a company to host hundreds of lightweight (e.g., EC2) servers all backed by a single copy of the block chain. Why force every single machine to have its own copy? All you really need to require is that each agency/participant have its own copy. > > They would not even have to run one. It could just pass the query to a random other node, and forward its result :) Ah, easy way to fix that. In fact, in my first draft of my suggestion, I had the answer, but I removed it because I thought it was superfluous. Challenge: "Send me: SHA256(SHA256(concatenation of N pseudo-randomly selected bytes from the block chain | prover's nonce | verifier's nonce))." The nonces are from the "version" messages exchanged at connection startup. A node can't pass the buck because it can't control the nonce that a random other node chooses.