Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id AE28D895 for ; Tue, 4 Aug 2015 21:47:17 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from outmail149084.authsmtp.net (outmail149084.authsmtp.net [62.13.149.84]) by smtp1.linuxfoundation.org (Postfix) with ESMTP id 1F9A2EA for ; Tue, 4 Aug 2015 21:47:16 +0000 (UTC) Received: from mail-c235.authsmtp.com (mail-c235.authsmtp.com [62.13.128.235]) by punt18.authsmtp.com (8.14.2/8.14.2/) with ESMTP id t74LlFD8002450; Tue, 4 Aug 2015 22:47:15 +0100 (BST) Received: from [25.114.14.211] ([24.114.75.173]) (authenticated bits=0) by mail.authsmtp.com (8.14.2/8.14.2/) with ESMTP id t74LlARP007838 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Tue, 4 Aug 2015 22:47:12 +0100 (BST) In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 From: Peter Todd Date: Tue, 04 Aug 2015 21:29:56 +0000 To: =?ISO-8859-1?Q?Jorge_Tim=F3n?= , =?ISO-8859-1?Q?Jorge_Tim=F3n_via_bitcoin-dev?= , Gavin Andresen Message-ID: <35CCF69C-D8FB-4E4E-BF58-FB61D07D60FB@petertodd.org> X-Server-Quench: 5e907a79-3af2-11e5-b398-002590a15da7 X-AuthReport-Spam: If SPAM / abuse - report it at: http://www.authsmtp.com/abuse X-AuthRoute: OCd2Yg0TA1ZNQRgX IjsJECJaVQIpKltL GxAVKBZePFsRUQkR bgdMdgYUGUATAgsB AmMbWVZeVFp7WGc7 aQ5PbARZfE1LQQRt U1dNRFdNFUssBhh9 Wm98MhlycA1FcDBx Z0BlXj5eCU16chd6 S1NXRDsEeGZhPWUC AkNRfx5UcAFPdx8U a1UrBXRDAzANdhEy HhM4ODE3eDlSNhEd aQYLNl8UWlsQVjA7 XRNKFD4zHFMMWyQ0 KVQ6KkQRB0YWNkkp YxMLXVUTMFkUNgxb EglTG2dcKlUATixj EQJfUAYAC3VXRSBX AVsuAhJJDTxOMgAA X-Authentic-SMTP: 61633532353630.1023:706 X-AuthFastPath: 0 (Was 255) X-AuthSMTP-Origin: 24.114.75.173/465 X-AuthVirus-Status: No virus detected - but ensure you scan with your own anti-virus system. X-Spam-Status: No, score=-2.6 required=5.0 tests=BAYES_00,RCVD_IN_DNSWL_LOW autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on smtp1.linux-foundation.org Cc: Bitcoin Dev Subject: Re: [bitcoin-dev] Consensus fork activation thresholds: Block.nTime vs median time vs block.nHeight 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, 04 Aug 2015 21:47:17 -0000 -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 On 4 August 2015 16:02:53 GMT-04:00, "Jorge Timón via bitcoin-dev" wrote: >One thing I've noticed there seems to be disagreement on is whether >miners' upgrade confirmation (aka voting) is necessary for >uncontroversial hardforks or not. 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. Another option is Hearn's proposal of using centralised checkpoints to override PoW consensus; obviously that raises serious questions, including legal issues. 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. -----BEGIN PGP SIGNATURE----- iQE9BAEBCAAnIBxQZXRlciBUb2RkIDxwZXRlQHBldGVydG9kZC5vcmc+BQJVwS7F AAoJEMCF8hzn9Lnc47AH/3926JLE4Rn9Fil+wvfxhfmBqIm0wtfStPDAqsQMDIbh kbxOw/Mai/AbqNUkYUWvoM2ZfJ/JNkA6HA977CE6huT1ozYVz8TJQmcqN/p1QXfX w1559UsXXop2fepY1dbnyBUwB6w6VwBrfj3awYkJsblgcdHrEsAesYeAHphAkwL/ kxQ0b+QmttaDCSK76hNloKVcN7AczdCSw1pux2rzmsG9zkwWJrIqR/prAO1nuk9Y LgQUCvYkZiMmMD8kNx9ZVRG2Y951uLS6594Qy6ZoAMAdA6QxNsP4qyE7s8M2HAon WjdS0UqTRyJuDVqpNav6WX4jTllK/UuHRUAOmBmYaRs= =0cKq -----END PGP SIGNATURE-----