Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id E575CAE7 for ; Tue, 30 Jun 2015 23:44:15 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from zinan.dashjr.org (zinan.dashjr.org [192.3.11.21]) by smtp1.linuxfoundation.org (Postfix) with ESMTP id 85714141 for ; Tue, 30 Jun 2015 23:44:15 +0000 (UTC) Received: from ishibashi.localnet (unknown [IPv6:2001:470:5:265:61b6:56a6:b03d:28d6]) (Authenticated sender: luke-jr) by zinan.dashjr.org (Postfix) with ESMTPSA id C9F82108039B; Tue, 30 Jun 2015 23:43:18 +0000 (UTC) X-Hashcash: 1:25:150630:bitcoin-dev@lists.linuxfoundation.org::TbXcP1F9IXUUc3kI:+6mv X-Hashcash: 1:25:150630:peter@grigor.ws::dqmRWgxYNTb7jihC:ctaos From: Luke Dashjr To: bitcoin-dev@lists.linuxfoundation.org Date: Tue, 30 Jun 2015 23:43:17 +0000 User-Agent: KMail/1.13.7 (Linux/3.14.41-gentoo; KDE/4.14.3; x86_64; ; ) References: In-Reply-To: X-PGP-Key-Fingerprint: E463 A93F 5F31 17EE DE6C 7316 BD02 9424 21F4 889F X-PGP-Key-ID: BD02942421F4889F X-PGP-Keyserver: hkp://pgp.mit.edu MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Message-Id: <201506302343.18048.luke@dashjr.org> X-Spam-Status: No, score=-2.5 required=5.0 tests=BAYES_00,RP_MATCHES_RCVD autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on smtp1.linux-foundation.org Subject: Re: [bitcoin-dev] A possible solution for the block size limit: Detection and rejection of bloated blocks by full nodes. X-BeenThere: bitcoin-dev@lists.linuxfoundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Bitcoin Development Discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 30 Jun 2015 23:44:16 -0000 On Tuesday, June 30, 2015 11:41:29 PM Peter Grigor wrote: > The block size debate centers around one concern it seems. To wit: if block > size is increased malicious miners may publish unreasonably large "bloated" > blocks. The way a miner would do this is to generate a plethora of private, > non-propagated transactions and include these in the block they solve. > > It seems to me that these bloated blocks could easily be detected by other > miners and full nodes: they will contain a very high percentage of > transactions that aren't found in the nodes' own memory pools. This > signature can be exploited to allow nodes to reject these bloated blocks. > The key here is that any malicious miner that publishes a block that is > bloated with his own transactions would contain a ridiculous number of > transactions that *absolutely no other full node has in its mempool*. > > Simply put, a threshold would be set by nodes on the allowable number of > non-mempool transactions allowed in a solved block (say, maybe, 50% -- I > really don't know what it should be). If a block is published which > contains more that this threshold of non-mempool transactions then it is > rejected. > > If this idea works the block size limitation could be completely removed. This is easily defeated simply by broadcasting the bloat beforehand... Luke