1a16477ff288e8fd440f4b783a12c949db1a6f
1 Return-Path: <pete@petertodd.org> 2 Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org 3 [172.17.192.35]) 4 by mail.linuxfoundation.org (Postfix) with ESMTPS id AE28D895 5 for <bitcoin-dev@lists.linuxfoundation.org>; 6 Tue, 4 Aug 2015 21:47:17 +0000 (UTC) 7 X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 8 Received: from outmail149084.authsmtp.net (outmail149084.authsmtp.net 9 [62.13.149.84]) 10 by smtp1.linuxfoundation.org (Postfix) with ESMTP id 1F9A2EA 11 for <bitcoin-dev@lists.linuxfoundation.org>; 12 Tue, 4 Aug 2015 21:47:16 +0000 (UTC) 13 Received: from mail-c235.authsmtp.com (mail-c235.authsmtp.com [62.13.128.235]) 14 by punt18.authsmtp.com (8.14.2/8.14.2/) with ESMTP id t74LlFD8002450; 15 Tue, 4 Aug 2015 22:47:15 +0100 (BST) 16 Received: from [25.114.14.211] ([24.114.75.173]) (authenticated bits=0) 17 by mail.authsmtp.com (8.14.2/8.14.2/) with ESMTP id t74LlARP007838 18 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); 19 Tue, 4 Aug 2015 22:47:12 +0100 (BST) 20 In-Reply-To: <CABm2gDonaiD_VxGoRHjXC8Ut3jxRG-cHVfdL9Y4voZz5m=z7SA@mail.gmail.com> 21 References: <CABm2gDoxr4yY6XPZOEG0CF_iPO+b1H3_yFoKnYa68Y4b=Tcwrw@mail.gmail.com> 22 <CABsx9T0c10SDHCBy5=iPKVvsNPmKr2ejUxLp0rJPZmPRPQpfig@mail.gmail.com> 23 <CABm2gDonaiD_VxGoRHjXC8Ut3jxRG-cHVfdL9Y4voZz5m=z7SA@mail.gmail.com> 24 MIME-Version: 1.0 25 Content-Transfer-Encoding: 8bit 26 Content-Type: text/plain; 27 charset=UTF-8 28 From: Peter Todd <pete@petertodd.org> 29 Date: Tue, 04 Aug 2015 21:29:56 +0000 30 To: =?ISO-8859-1?Q?Jorge_Tim=F3n?= <jtimon@jtimon.cc>, 31 =?ISO-8859-1?Q?Jorge_Tim=F3n_via_bitcoin-dev?= 32 <bitcoin-dev@lists.linuxfoundation.org>, 33 Gavin Andresen <gavinandresen@gmail.com> 34 Message-ID: <35CCF69C-D8FB-4E4E-BF58-FB61D07D60FB@petertodd.org> 35 X-Server-Quench: 5e907a79-3af2-11e5-b398-002590a15da7 36 X-AuthReport-Spam: If SPAM / abuse - report it at: 37 http://www.authsmtp.com/abuse 38 X-AuthRoute: OCd2Yg0TA1ZNQRgX IjsJECJaVQIpKltL GxAVKBZePFsRUQkR 39 bgdMdgYUGUATAgsB AmMbWVZeVFp7WGc7 aQ5PbARZfE1LQQRt 40 U1dNRFdNFUssBhh9 Wm98MhlycA1FcDBx Z0BlXj5eCU16chd6 41 S1NXRDsEeGZhPWUC AkNRfx5UcAFPdx8U a1UrBXRDAzANdhEy 42 HhM4ODE3eDlSNhEd aQYLNl8UWlsQVjA7 XRNKFD4zHFMMWyQ0 43 KVQ6KkQRB0YWNkkp YxMLXVUTMFkUNgxb EglTG2dcKlUATixj 44 EQJfUAYAC3VXRSBX AVsuAhJJDTxOMgAA 45 X-Authentic-SMTP: 61633532353630.1023:706 46 X-AuthFastPath: 0 (Was 255) 47 X-AuthSMTP-Origin: 24.114.75.173/465 48 X-AuthVirus-Status: No virus detected - but ensure you scan with your own 49 anti-virus system. 50 X-Spam-Status: No, score=-2.6 required=5.0 tests=BAYES_00,RCVD_IN_DNSWL_LOW 51 autolearn=ham version=3.3.1 52 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on 53 smtp1.linux-foundation.org 54 Cc: Bitcoin Dev <bitcoin-dev@lists.linuxfoundation.org> 55 Subject: Re: [bitcoin-dev] Consensus fork activation thresholds: Block.nTime 56 vs median time vs block.nHeight 57 X-BeenThere: bitcoin-dev@lists.linuxfoundation.org 58 X-Mailman-Version: 2.1.12 59 Precedence: list 60 List-Id: Bitcoin Development Discussion <bitcoin-dev.lists.linuxfoundation.org> 61 List-Unsubscribe: <https://lists.linuxfoundation.org/mailman/options/bitcoin-dev>, 62 <mailto:bitcoin-dev-request@lists.linuxfoundation.org?subject=unsubscribe> 63 List-Archive: <http://lists.linuxfoundation.org/pipermail/bitcoin-dev/> 64 List-Post: <mailto:bitcoin-dev@lists.linuxfoundation.org> 65 List-Help: <mailto:bitcoin-dev-request@lists.linuxfoundation.org?subject=help> 66 List-Subscribe: <https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev>, 67 <mailto:bitcoin-dev-request@lists.linuxfoundation.org?subject=subscribe> 68 X-List-Received-Date: Tue, 04 Aug 2015 21:47:17 -0000 69 70 -----BEGIN PGP SIGNED MESSAGE----- 71 Hash: SHA256 72 73 74 75 On 4 August 2015 16:02:53 GMT-04:00, "Jorge Timón via bitcoin-dev" <bitcoin-dev@lists.linuxfoundation.org> wrote: 76 >One thing I've noticed there seems to be disagreement on is whether 77 >miners' upgrade confirmation (aka voting) is necessary for 78 >uncontroversial hardforks or not. 79 80 To be clear, without a strong supermajority of miner support the fork risks attack. Requiring 95% approval - which is actually just a 50% majority vote as the majority can squelch the minority - is an obvious minimum safety requirement. 81 82 Another option is Hearn's proposal of using centralised checkpoints to override PoW consensus; obviously that raises serious questions, including legal issues. 83 84 For forks without miner approval miners have a number of options to defeat them. For instance, they can make their own fork with a new consensus algorithm that requires miners to prove they're attacking the unwanted chain - Garzik's recent 2MB blocks proposal is a hilarious, and probably accidental, example of such a design, with the original Bitcoin protocol rules having the effect of attacking the Garzik 2MB chain. 85 86 -----BEGIN PGP SIGNATURE----- 87 88 iQE9BAEBCAAnIBxQZXRlciBUb2RkIDxwZXRlQHBldGVydG9kZC5vcmc+BQJVwS7F 89 AAoJEMCF8hzn9Lnc47AH/3926JLE4Rn9Fil+wvfxhfmBqIm0wtfStPDAqsQMDIbh 90 kbxOw/Mai/AbqNUkYUWvoM2ZfJ/JNkA6HA977CE6huT1ozYVz8TJQmcqN/p1QXfX 91 w1559UsXXop2fepY1dbnyBUwB6w6VwBrfj3awYkJsblgcdHrEsAesYeAHphAkwL/ 92 kxQ0b+QmttaDCSK76hNloKVcN7AczdCSw1pux2rzmsG9zkwWJrIqR/prAO1nuk9Y 93 LgQUCvYkZiMmMD8kNx9ZVRG2Y951uLS6594Qy6ZoAMAdA6QxNsP4qyE7s8M2HAon 94 WjdS0UqTRyJuDVqpNav6WX4jTllK/UuHRUAOmBmYaRs= 95 =0cKq 96 -----END PGP SIGNATURE----- 97 98