From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id CC1974A6 for ; Sat, 25 Mar 2017 20:33:55 +0000 (UTC) X-Greylist: delayed 00:05:04 by SQLgrey-1.7.6 Received: from mout.gmx.net (mout.gmx.net [212.227.15.18]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 6357118A for ; Sat, 25 Mar 2017 20:33:54 +0000 (UTC) Received: from [192.168.50.29] ([24.86.172.170]) by mail.gmx.com (mrgmx001 [212.227.17.184]) with ESMTPSA (Nemesis) id 0LqylH-1cDqW43kzj-00eblM; Sat, 25 Mar 2017 21:28:48 +0100 Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 8.2 \(2104\)) From: Peter R In-Reply-To: Date: Sat, 25 Mar 2017 13:28:44 -0700 Content-Transfer-Encoding: quoted-printable Message-Id: <9C2A6867-470D-4336-8439-17F4E0CA4B17@gmx.com> References: <5b9ba6c4-6d8f-9c0b-2420-2be6c30f87b5@cannon-ciota.info> <35ba77db-f95a-4517-c960-8ad42a633ba0@gmail.com> To: Bitcoin Protocol Discussion X-Mailer: Apple Mail (2.2104) X-Provags-ID: V03:K0:VjSSe95/B1INjwMMhfQZYHKiqyhZ5lUZCziF5ietTg2irVFYWSG UkJzdSHyBeA2if+AN8uOj6UghWUXq38Dchzawd/3zbyMY9qJpd2Ki905aqLUo+wHGFl/KKN LudCEFsjO2Bntc2lcSv3NkEbrPGoNWqTvSTP5TrHG9h01BdmxnRB37Wb4LLGZzQuOS0Ocwk mUCsmWkx46jjOGK0WH4dQ== X-UI-Out-Filterresults: notjunk:1;V01:K0:Q1B3TRxz1AY=:JjXAye0BLc/hecCkgU78Ke YflUJjMYOsqjRIe0UVp5x7Jct0HQjn8m+QGcaAc2n3J8X2r8g/GNh+ULsU26KKkBtYgt3JEyT c0hnf6fc5nAoI5+7zrmulxcK03O97wbXva42xrj8SiXW/3WDe9X/riotBr0C6i20KXWaIfCAT d06CjWiNcTR15z0X4+wRAZhQInoz6enX3DANxedpy/7mmyF9AsmMgvPgzbLqu7ekM7j0UWKHb tUqMoZcZ5zSSlBX6/jbPdW7W3ThdNfdbVTbHG5+NQOQKl7rv8OuQy87f2+6pD7ABNsDDLOFwL tZKidxy7OO7MLUW0b3MDJ2hQDqFwjxq164r/CgObLZovvOoOnp/pmf8RKzgGox9uoYD1niJFT 2iAQSEo5r8zIHLEbOD/rjvyMw1FP/RZMhAf/H7oDBkVsxLyO1IvaMko1SFpgLZJNh0CyEtqMy Nqv278gZktaV6YnXZAguFi5d4KkL9IzkAqpas833XRvu71G9PO8eyohvP1PrmMhBWso+qfnXk VyWndj0Gsy05C0w22HuGg4dqmMp44hkAHu8Pm2gjHjduarbnvREeGews6rLVrYT6lo0khRvJQ Dr5YhWncn0dbdQIhnAe2Wyof89CIeqxCEjtWU+Nto1/TbcmQHI8TahVUwqAc7kEyceMOLjr7M C5/bP9B6ax5+ISHSfMfoJpL28ikOQMM+kCRk0O0AFO6IV556UzT3ePOdtJYvWlWn9wdzVWsyO /2dbLU4GuHEcxm/1dwcifhT6v/iQA0bFw1j8j9iEcHC/HRGcx0buD1Tb9MCoPeHISIJloEisP p7MweUD X-Spam-Status: No, score=-2.6 required=5.0 tests=BAYES_00,FREEMAIL_FROM, LOTS_OF_MONEY, RCVD_IN_DNSWL_LOW, T_MONEY_PERCENT autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on smtp1.linux-foundation.org X-Mailman-Approved-At: Sat, 25 Mar 2017 22:54:17 +0000 Subject: Re: [bitcoin-dev] Defending against empty or near empty blocks from malicious miner takeover? X-BeenThere: bitcoin-dev@lists.linuxfoundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Bitcoin Protocol Discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 25 Mar 2017 20:33:55 -0000 One of the purported benefits of a soft-forking change (a tightening of = the consensus rule set) is the reduced risk of a blockchain split = compared to a loosening of the consensus rule set. The way this works = is that miners who fail to upgrade to the new tighter ruleset will have = their non-compliant blocks orphaned by the hash power majority. This is = a strong incentive to upgrade and has historically worked well. If a = minority subset of the network didn=E2=80=99t want to abide by the new = restricted rule set, a reasonable solution would be for them to change = the proof-of-work and start a spin-off from the existing Bitcoin ledger = (https://bitcointalk.org/index.php?topic=3D563972.0). In the case of the coming network upgrade to larger blocks, a primary = concern of both business such as Coinbase and Bitpay, and most miners, = is the possibility of a blockchain split and the associated confusion, = replay risk, etc. By applying techniques that are known to be = successful for soft-forking changes, we can likewise benefit in a way = that makes a split less likely as we move towards larger blocks. Two = proposed techniques to reduce the chances of a split are: 1. That miners begin to orphan the blocks of non-upgraded miners once a = super-majority of the network hash power has upgraded. This would serve = as an expensive-to-ignore reminder to upgrade. 2. That, in the case where a minority branch emerges (unlikely IMO), = majority miners would continually re-org that minority branch with empty = blocks to prevent transactions from confirming, thereby eliminating = replay risk. Just like after a soft forking change, a minority that does not want to = abide by the current ruleset enforced by the majority could change the = proof-of-work and start a spin-off from the existing Bitcoin ledger, as = suggested by Emin. =20 Best regards, Peter R > On Mar 25, 2017, at 9:12 AM, CANNON via bitcoin-dev = wrote: >=20 > On 03/24/2017 07:00 PM, Aymeric Vitte wrote: >> I don't know what "Time is running short I fear" stands for and when = 50% >> is supposed to be reached >=20 > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA512 >=20 > On 03/24/2017 07:00 PM, Aymeric Vitte wrote: > I don't know what > "Time is running short I fear" stands for and when 50% > is supposed > to be reached >=20 > According to current hashrate distribution tracking site coin.dance, > very likely within less than four weeks according to current hashrate > takeover rate. >=20 > While a fork is very likely, that I dont really fear because worst > case scenario is that bitcoin still survives and the invalid chain > becomes an alt. My fear is the centralized mining power being used > to attack the valid chain with intentions on killing it. [1] >=20 > Shouldn't this 50% attack they are threatening be a concern? If it > is a concern, what options are on the table. If it is not a concern > please enlightent me as to why. >=20 >=20 > [1] Source: > = https://www.reddit.com/r/Bitcoin/comments/6172s3/peter_rizun_tells_miners_= to_force_a_hard_fork_by/ >=20 > Text: >=20 > The attack quoted from his article: > = https://medium.com/@peter_r/on-the-emerging-consensus-regarding-bitcoins-b= lock-size-limit-insights-from-my-visit-with-2348878a16d8 >=20 > [Level 2] Anti-split protection=E2=80=8A=E2=80=8AMiners will orphan = the > blocks of non-compliant miners prior to the first larger block > to serve as a reminder to upgrade. Simply due to the possibility > of having blocks orphaned, all miners would be motivated to > begin signalling for larger blocks once support definitively > passes 51%. If some miners hold out (e.g., they may not be > paying attention regarding the upgrade), then they will begin > to pay attention after losing approximately $15,000 of revenue > due to an orphaned block. >=20 > [Level 3] Anti-split protection=E2=80=8A=E2=80=8AIn the scenario = where Levels > 1 and 2 protection fails to entice all non-compliant miners to > upgrade, a small-block minority chain may emerge. To address the > risk of coins being spent on this chain (replay risk), majority > miners will deploy hash power as needed to ensure the minority > chain includes only empty blocks after the forking point. This > can easily be accomplished if the majority miners maintain a > secret chain of empty blocks=E2=80=8A=E2=80=8Abuilt off their last = empty > block=E2=80=8A=E2=80=8Apublishing only as much of this chain as = necessary > to orphan any non-empty blocks produced on the minority chain. >=20 >=20 >=20 >=20 > - -- > Cannon > PGP Fingerprint: 2BB5 15CD 66E7 4E28 45DC 6494 A5A2 2879 3F06 E832=20 > Email: cannon@cannon-ciota.info >=20 > NOTICE: ALL EMAIL CORRESPONDENCE NOT SIGNED/ENCRYPTED WITH PGP SHOULD=20= > BE CONSIDERED POTENTIALLY FORGED, AND NOT PRIVATE.=20 > If this matters to you, use PGP. > -----BEGIN PGP SIGNATURE----- >=20 > iQIcBAEBCgAGBQJY1pbaAAoJEAYDai9lH2mwOO0QANOWqGzPNlifWguc+Y5UQxQM > eAiztAayQBoAyLcFE7/qdtSNlUxbIAHG17fM+aNkehjYH2oN5ODJ+j7E2Yt6EoUH > h5t8MLhNRG/YGF1hJK8Io940EmdcjuNmohiZvrjIqEOYggmLU3hR6J4gsuGsQQhu > gY3sMS/TtT+gZNH8w53ePGrsVhuQR7yEMMr91/vM4+Q5abpwqLeYLnslaZDcd3XK > VB9vyyK08r34J1GQt/H4UvTvGs28MFKBkvueA/Sfyvnrih7+WSQLuSvhiFr+cW1B > TmSVYrB2DzyHN27jDCI2ty3ryNE4PMYcaeLfI2TTbsD/MuVU5lK0kM/1JajP4eRj > j+P03OipuQiy/dNU63w0Uka2PbdKhDC13hVtK/ttBbNppbjnGeB9PYSJCzOpInGw > NwAyz0rVS/llGsdctcII7Z6AUMGuJXzsosY8vjUroU+KFRDqIbDfC53sH7DaPh7u > YawwId5S5RnZsAGCUJ+qNcg0s728J1eDjofN291IS5sOKMzpI7KhaOhFxjnk1MpN > ZAlQeTlvG+sAdn61QMQK1NbFt0km+jcqyVh0+L01yB0K4VDi1YFJaSBOaYUELBXa > 8a6WhZf5nrl5UIpH7rRcPzzqchcdYczy5VRZp2UsU+HYeqLXlcN0a03yPpVQik9S > /T93MuZgmvSCry5MlccA > =3DR71g > -----END PGP SIGNATURE----- >=20 > _______________________________________________ > bitcoin-dev mailing list > bitcoin-dev@lists.linuxfoundation.org > https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev