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| author | James Hilliard <james.hilliard1@gmail.com> | 2017-06-06 20:54:37 -0500 |
|---|---|---|
| committer | bitcoindev <bitcoindev@gnusha.org> | 2017-06-07 01:54:40 +0000 |
| commit | fc0ab8440690b57dcf87c3982e15f2cbdceb1f2b (patch) | |
| tree | 910cc7ec6ddc8769f8ba7be07044abfd0d01d2da | |
| parent | 089689d7be2b23eac5b3906463d4a04ce7861dfd (diff) | |
| download | pi-bitcoindev-fc0ab8440690b57dcf87c3982e15f2cbdceb1f2b.tar.gz pi-bitcoindev-fc0ab8440690b57dcf87c3982e15f2cbdceb1f2b.zip | |
Re: [bitcoin-dev] User Activated Soft Fork Split Protection
| -rw-r--r-- | 9e/9e4016749f0314af1180c6bbb84fa16f34091e | 281 |
1 files changed, 281 insertions, 0 deletions
diff --git a/9e/9e4016749f0314af1180c6bbb84fa16f34091e b/9e/9e4016749f0314af1180c6bbb84fa16f34091e new file mode 100644 index 000000000..ce67c5c93 --- /dev/null +++ b/9e/9e4016749f0314af1180c6bbb84fa16f34091e @@ -0,0 +1,281 @@ +Return-Path: <james.hilliard1@gmail.com> +Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org + [172.17.192.35]) + by mail.linuxfoundation.org (Postfix) with ESMTPS id 174ECB76 + for <bitcoin-dev@lists.linuxfoundation.org>; + Wed, 7 Jun 2017 01:54:40 +0000 (UTC) +X-Greylist: whitelisted by SQLgrey-1.7.6 +Received: from mail-oi0-f43.google.com (mail-oi0-f43.google.com + [209.85.218.43]) + by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 2A23C1DF + for <bitcoin-dev@lists.linuxfoundation.org>; + Wed, 7 Jun 2017 01:54:39 +0000 (UTC) +Received: by mail-oi0-f43.google.com with SMTP id p7so5949311oif.2 + for <bitcoin-dev@lists.linuxfoundation.org>; + Tue, 06 Jun 2017 18:54:39 -0700 (PDT) +DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; + h=mime-version:in-reply-to:references:from:date:message-id:subject:to + :cc; bh=dzqm6L1bgsIWuZ2GZ8eVmKLbC7heWqw7qU+diOCXCjA=; + b=U4sgU1N/GxalKHQzRU1f6fTBY33+gyoT8d++kkvAxL1NqPkh7l9eiUxtUlbxoodv9O + 27PW3MfdtMO0r8TJA29QPuoYe/EWMUQkJkR1I+SypjG5qshBqyGVpj1aykhL3JvWWRAE + oIW8DlY8AB6yn++oTa/AehcaYfm+67bTQ9B/lTjUdZntdpSLIKwCK7wYkJVXIy/ySjQ6 + rKFX3TkueCgV72qccvCJvRz40jP/r5u7t9/WdTxLJ8yIZSoH7PKfSpcsuUipyVUwl6RU + 6F7pxKQnEO17xSMQgWFUpywKPC/Kh8TYGAcFm7Qda3ZpT5EWv4ubfSaORJ/yGVmJ1vu3 + UTCQ== +X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; + d=1e100.net; s=20161025; + h=x-gm-message-state:mime-version:in-reply-to:references:from:date + :message-id:subject:to:cc; + bh=dzqm6L1bgsIWuZ2GZ8eVmKLbC7heWqw7qU+diOCXCjA=; + b=oFN0LuJ1to3PkOg2ZgiIO/FyoYbT5K3N48WHPB8rZAzxMMOe0aYXvhLMTjhZ2uSgYw + JIVFgC4TBSQABvplKwoh6Eyqv7AmMp9Pnmww0ENIlsXZ3M7p5aEg2biXI46W7mcy346+ + AJ6zYM/IfCsgDClmgnCi4qR0Mn2YiRBmNPckeBnz7p7l5PMnMXM61qu88NL0GZYNLCMd + deFVWv9iGSYwsI2u7ztTfjk6D6e5X6Rmi45ko7NDEdJSh9KbT7TG2ODnTyR61yKNLoZ/ + X9ebIaWRRzuBZs1NjBRZcyWbm9ZBYNTSb6htMGyI4fNHGCawt/Zb5jhnxB3TTYrkh2/k + 19Kw== +X-Gm-Message-State: AODbwcAL6ZBch8F+F7qXrPnnav9x0+61+nJrvAwreSnZWaBZvYtTs7Vr + zU2XtxpzpwRt6y2b2Vzeo14BXGMZmKSX +X-Received: by 10.202.87.21 with SMTP id l21mr13781219oib.214.1496800478362; + Tue, 06 Jun 2017 18:54:38 -0700 (PDT) +MIME-Version: 1.0 +Received: by 10.182.224.230 with HTTP; Tue, 6 Jun 2017 18:54:37 -0700 (PDT) +In-Reply-To: <AE5BA251-9DA6-4E34-A748-11C8CF91977C@taoeffect.com> +References: <CADvTj4qpH-t5Gx6qyn3yToyUE_GFaBE989=AWNHLKMpMNW3R+w@mail.gmail.com> + <AE5BA251-9DA6-4E34-A748-11C8CF91977C@taoeffect.com> +From: James Hilliard <james.hilliard1@gmail.com> +Date: Tue, 6 Jun 2017 20:54:37 -0500 +Message-ID: <CADvTj4q+oOS=DKfpiNQ6PAbksQfa1gKNfokr2Zc6PNGWqLyL4A@mail.gmail.com> +To: Tao Effect <contact@taoeffect.com> +Content-Type: text/plain; charset="UTF-8" +X-Spam-Status: No, score=-1.7 required=5.0 tests=BAYES_00,DKIM_SIGNED, + DKIM_VALID,DKIM_VALID_AU,FREEMAIL_ENVFROM_END_DIGIT,FREEMAIL_FROM, + RCVD_IN_DNSWL_NONE autolearn=no version=3.3.1 +X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on + smtp1.linux-foundation.org +Cc: Bitcoin Dev <bitcoin-dev@lists.linuxfoundation.org> +Subject: Re: [bitcoin-dev] User Activated Soft Fork Split Protection +X-BeenThere: bitcoin-dev@lists.linuxfoundation.org +X-Mailman-Version: 2.1.12 +Precedence: list +List-Id: Bitcoin Protocol Discussion <bitcoin-dev.lists.linuxfoundation.org> +List-Unsubscribe: <https://lists.linuxfoundation.org/mailman/options/bitcoin-dev>, + <mailto:bitcoin-dev-request@lists.linuxfoundation.org?subject=unsubscribe> +List-Archive: <http://lists.linuxfoundation.org/pipermail/bitcoin-dev/> +List-Post: <mailto:bitcoin-dev@lists.linuxfoundation.org> +List-Help: <mailto:bitcoin-dev-request@lists.linuxfoundation.org?subject=help> +List-Subscribe: <https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev>, + <mailto:bitcoin-dev-request@lists.linuxfoundation.org?subject=subscribe> +X-List-Received-Date: Wed, 07 Jun 2017 01:54:40 -0000 + +This is a BIP8 style soft fork so mandatory signalling will be active +after Aug 1st regardless. + +On Tue, Jun 6, 2017 at 8:51 PM, Tao Effect <contact@taoeffect.com> wrote: +> What is the probability that a 65% threshold is too low and can allow a +> "surprise miner attack", whereby miners are kept offline before the +> deadline, and brought online immediately after, creating potential havoc? +> +> (Nit: "simple majority" usually refers to >50%, I think, might cause +> confusion.) +> +> -Greg Slepak +> +> -- +> Please do not email me anything that you are not comfortable also sharing +> with the NSA. +> +> On Jun 6, 2017, at 5:56 PM, James Hilliard via bitcoin-dev +> <bitcoin-dev@lists.linuxfoundation.org> wrote: +> +> Due to the proposed calendar(https://segwit2x.github.io/) for the +> SegWit2x agreement being too slow to activate SegWit mandatory +> signalling ahead of BIP148 using BIP91 I would like to propose another +> option that miners can use to prevent a chain split ahead of the Aug +> 1st BIP148 activation date. +> +> The splitprotection soft fork is essentially BIP91 but using BIP8 +> instead of BIP9 with a lower activation threshold and immediate +> mandatory signalling lock-in. This allows for a majority of miners to +> activate mandatory SegWit signalling and prevent a potential chain +> split ahead of BIP148 activation. +> +> This BIP allows for miners to respond to market forces quickly ahead +> of BIP148 activation by signalling for splitprotection. Any miners +> already running BIP148 should be encouraged to use splitprotection. +> +> <pre> +> BIP: splitprotection +> Layer: Consensus (soft fork) +> Title: User Activated Soft Fork Split Protection +> Author: James Hilliard <james.hilliard1@gmail.com> +> Comments-Summary: No comments yet. +> Comments-URI: +> Status: Draft +> Type: Standards Track +> Created: 2017-05-22 +> License: BSD-3-Clause +> CC0-1.0 +> </pre> +> +> ==Abstract== +> +> This document specifies a coordination mechanism for a simple majority +> of miners to prevent a chain split ahead of BIP148 activation. +> +> ==Definitions== +> +> "existing segwit deployment" refer to the BIP9 "segwit" deployment +> using bit 1, between November 15th 2016 and November 15th 2017 to +> activate BIP141, BIP143 and BIP147. +> +> ==Motivation== +> +> The biggest risk of BIP148 is an extended chain split, this BIP +> provides a way for a simple majority of miners to eliminate that risk. +> +> This BIP provides a way for a simple majority of miners to coordinate +> activation of the existing segwit deployment with less than 95% +> hashpower before BIP148 activation. Due to time constraints unless +> immediately deployed BIP91 will likely not be able to enforce +> mandatory signalling of segwit before the Aug 1st activation of +> BIP148. This BIP provides a method for rapid miner activation of +> SegWit mandatory signalling ahead of the BIP148 activation date. Since +> the primary goal of this BIP is to reduce the chance of an extended +> chain split as much as possible we activate using a simple miner +> majority of 65% over a 504 block interval rather than a higher +> percentage. This BIP also allows miners to signal their intention to +> run BIP148 in order to prevent a chain split. +> +> ==Specification== +> +> While this BIP is active, all blocks must set the nVersion header top +> 3 bits to 001 together with bit field (1<<1) (according to the +> existing segwit deployment). Blocks that do not signal as required +> will be rejected. +> +> ==Deployment== +> +> This BIP will be deployed by "version bits" with a 65%(this can be +> adjusted if desired) activation threshold BIP9 with the name +> "splitprotecion" and using bit 2. +> +> This BIP starts immediately and is a BIP8 style soft fork since +> mandatory signalling will start on midnight August 1st 2017 (epoch +> time 1501545600) regardless of whether or not this BIP has reached its +> own signalling threshold. This BIP will cease to be active when segwit +> is locked-in. +> +> === Reference implementation === +> +> <pre> +> // Check if Segregated Witness is Locked In +> bool IsWitnessLockedIn(const CBlockIndex* pindexPrev, const +> Consensus::Params& params) +> { +> LOCK(cs_main); +> return (VersionBitsState(pindexPrev, params, +> Consensus::DEPLOYMENT_SEGWIT, versionbitscache) == +> THRESHOLD_LOCKED_IN); +> } +> +> // SPLITPROTECTION mandatory segwit signalling. +> if ( VersionBitsState(pindex->pprev, chainparams.GetConsensus(), +> Consensus::DEPLOYMENT_SPLITPROTECTION, versionbitscache) == +> THRESHOLD_LOCKED_IN && +> !IsWitnessLockedIn(pindex->pprev, chainparams.GetConsensus()) && +> // Segwit is not locked in +> !IsWitnessEnabled(pindex->pprev, chainparams.GetConsensus()) ) // +> and is not active. +> { +> bool fVersionBits = (pindex->nVersion & VERSIONBITS_TOP_MASK) == +> VERSIONBITS_TOP_BITS; +> bool fSegbit = (pindex->nVersion & +> VersionBitsMask(chainparams.GetConsensus(), +> Consensus::DEPLOYMENT_SEGWIT)) != 0; +> if (!(fVersionBits && fSegbit)) { +> return state.DoS(0, error("ConnectBlock(): relayed block must +> signal for segwit, please upgrade"), REJECT_INVALID, "bad-no-segwit"); +> } +> } +> +> // BIP148 mandatory segwit signalling. +> int64_t nMedianTimePast = pindex->GetMedianTimePast(); +> if ( (nMedianTimePast >= 1501545600) && // Tue 01 Aug 2017 00:00:00 UTC +> (nMedianTimePast <= 1510704000) && // Wed 15 Nov 2017 00:00:00 UTC +> (!IsWitnessLockedIn(pindex->pprev, chainparams.GetConsensus()) && +> // Segwit is not locked in +> !IsWitnessEnabled(pindex->pprev, chainparams.GetConsensus())) ) +> // and is not active. +> { +> bool fVersionBits = (pindex->nVersion & VERSIONBITS_TOP_MASK) == +> VERSIONBITS_TOP_BITS; +> bool fSegbit = (pindex->nVersion & +> VersionBitsMask(chainparams.GetConsensus(), +> Consensus::DEPLOYMENT_SEGWIT)) != 0; +> if (!(fVersionBits && fSegbit)) { +> return state.DoS(0, error("ConnectBlock(): relayed block must +> signal for segwit, please upgrade"), REJECT_INVALID, "bad-no-segwit"); +> } +> } +> </pre> +> +> https://github.com/bitcoin/bitcoin/compare/0.14...jameshilliard:splitprotection-v0.14.1 +> +> ==Backwards Compatibility== +> +> This deployment is compatible with the existing "segwit" bit 1 +> deployment scheduled between midnight November 15th, 2016 and midnight +> November 15th, 2017. This deployment is also compatible with the +> existing BIP148 deployment. This BIP is compatible with BIP91 only if +> BIP91 activates before it and before BIP148. Miners will need to +> upgrade their nodes to support splitprotection otherwise they may +> build on top of an invalid block. While this bip is active users +> should either upgrade to splitprotection or wait for additional +> confirmations when accepting payments. +> +> ==Rationale== +> +> Historically we have used IsSuperMajority() to activate soft forks +> such as BIP66 which has a mandatory signalling requirement for miners +> once activated, this ensures that miners are aware of new rules being +> enforced. This technique can be leveraged to lower the signalling +> threshold of a soft fork while it is in the process of being deployed +> in a backwards compatible way. We also use a BIP8 style timeout to +> ensure that this BIP is compatible with BIP148 and that BIP148 +> compatible mandatory signalling activates regardless of miner +> signalling levels. +> +> By orphaning non-signalling blocks during the BIP9 bit 1 "segwit" +> deployment, this BIP can cause the existing "segwit" deployment to +> activate without needing to release a new deployment. As we approach +> BIP148 activation it may be desirable for a majority of miners to have +> a method that will ensure that there is no chain split. +> +> ==References== +> +> *[https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2017-March/013714.html +> Mailing list discussion] +> *[https://github.com/bitcoin/bitcoin/blob/v0.6.0/src/main.cpp#L1281-L1283 +> P2SH flag day activation] +> *[[bip-0009.mediawiki|BIP9 Version bits with timeout and delay]] +> *[[bip-0016.mediawiki|BIP16 Pay to Script Hash]] +> *[[bip-0091.mediawiki|BIP91 Reduced threshold Segwit MASF]] +> *[[bip-0141.mediawiki|BIP141 Segregated Witness (Consensus layer)]] +> *[[bip-0143.mediawiki|BIP143 Transaction Signature Verification for +> Version 0 Witness Program]] +> *[[bip-0147.mediawiki|BIP147 Dealing with dummy stack element malleability]] +> *[[bip-0148.mediawiki|BIP148 Mandatory activation of segwit deployment]] +> *[[bip-0149.mediawiki|BIP149 Segregated Witness (second deployment)]] +> *[https://bitcoincore.org/en/2016/01/26/segwit-benefits/ Segwit benefits] +> +> ==Copyright== +> +> This document is dual licensed as BSD 3-clause, and Creative Commons +> CC0 1.0 Universal. +> _______________________________________________ +> bitcoin-dev mailing list +> bitcoin-dev@lists.linuxfoundation.org +> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev +> +> + |