Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 7BA1BBDE for ; Wed, 7 Jun 2017 21:44:55 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.7.6 Received: from mail-oi0-f51.google.com (mail-oi0-f51.google.com [209.85.218.51]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 6835016C for ; Wed, 7 Jun 2017 21:44:54 +0000 (UTC) Received: by mail-oi0-f51.google.com with SMTP id o65so11275094oif.1 for ; Wed, 07 Jun 2017 14:44:54 -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:content-transfer-encoding; bh=KtGPL8Kfo3tF9c4pOwg5YYYtHS2LGHuNVb7vZ5Vcrnc=; b=jVb9GO2els6w3Eq1XOVQpBZaAW2SWuvWzWckk8a5fh7/WSvZ2/LnHGldVnQRx5dvn1 JUQ0Pq9IhdXLDSvyssuJtaD+8KPglaBC7RMR2CgaS/Ppc4ng+z73ofnEeHL2g6WXOt/H H4NFh+oPL/Cy4O8HfOXTq/9cqNLKMLqidfU8gLc9mxIPwGvjjElE90DINirbyIPJcXOF HobDWpgQEzKrtL6qonHbNSDLCXGPJENCtDIkMuTMvnKgZLfYCgMeOpQi0+zOA+/TWTad HpUTXS/QAkiMOXjFW1PA8kOF9TWnckixh1Ifg7wOJvtYT2uqCu+tSL6NZdxiUG+JltZo 6FZQ== 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:content-transfer-encoding; bh=KtGPL8Kfo3tF9c4pOwg5YYYtHS2LGHuNVb7vZ5Vcrnc=; b=E03bU+uVu51rFT79yuoCDLI24IDKKrPoYe96jif61hlFBpSSw9bGlBUbqyEIWdYJLd h3iR0d5REm811IIQY/3zzGRfTgourdMkTDGxhSXqT5/eewA3jtcdE5GEdmkeUMI37S/0 mQMXqGG5Ui77LHY7t59KS65oIK1XTDa34YH+bxMxZFWmU7BU3CiH7bPPvCYr++yGMPsV 1LElecw3FVDE/bhftMfswDtFChESeovGYEGXTBetMfU1s8LKq3YMfgmpuncTE0bKl2vp SAhQdLytr8Qcr7cMKGS2ek8clvI5vO5dEQMEBvLcN2abEOiLz+xhsLs8jXMtRgM8jHc5 jT0g== X-Gm-Message-State: AODbwcDT3hK05I9XQh+mXD/kVukfv4dtXGMxBNmy1XqUCB7hRFUrXmV6 1bB47EaUjcuJ7ylhLkesN4cqg5PQW7XB X-Received: by 10.202.87.87 with SMTP id l84mr753239oib.214.1496871893509; Wed, 07 Jun 2017 14:44:53 -0700 (PDT) MIME-Version: 1.0 Received: by 10.182.224.230 with HTTP; Wed, 7 Jun 2017 14:44:52 -0700 (PDT) In-Reply-To: References: <0CDEF5A2-0BAF-46E4-8906-39D4724AF3F2@taoeffect.com> From: James Hilliard Date: Wed, 7 Jun 2017 16:44:52 -0500 Message-ID: To: Jared Lee Richardson Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable 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 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 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 07 Jun 2017 21:44:55 -0000 Yes, this is the same as BIP148, there is no mandatory signalling after segwit is locked in. On Wed, Jun 7, 2017 at 4:43 PM, Jared Lee Richardson w= rote: >> Keep in mind that this is only temporary until segwit has locked in, > after that happens it becomes optional for miners again. > > I missed that, that does effectively address that concern. It appears > that BIP148 implements the same rule as would be required to prevent a > later chainsplit as well, no? > > This comment did bring to mind another concern about BIP148/91 though, > which I'll raise in the pull request discussion. Feel free to respond > to it there. > > Jared > > On Wed, Jun 7, 2017 at 2:21 PM, James Hilliard > wrote: >> Keep in mind that this is only temporary until segwit has locked in, >> after that happens it becomes optional for miners again. >> >> On Wed, Jun 7, 2017 at 4:09 PM, Jared Lee Richardson wrote: >>>> This is, by far, the safest way for miners to quickly defend against a= chain split, much better than a -bip148 option. This allows miners to de= fend themselves, with very little risk, since the defense is only activated= if the majority of miners do so. I would move for a very rapid deployment.= Only miners would need to upgrade. Regular users would not have to con= cern themselves with this release. >>> >>> FYI, even if very successful, this deployment and change may have a >>> severe negative impact on a small group of miners. Any miners/pools >>> who are not actively following the forums, news, or these discussions >>> may be difficult to reach and communicate with in time, particularly >>> with language barriers. Of those, any who are also either not >>> signaling segwit currently or are running an older software version >>> will have their blocks continuously and constantly orphaned, but may >>> not have any alarms or notifications set up for such an unexpected >>> failure. That may or may not be a worthy consideration, but it is >>> definitely brusque and a harsh price to pay. Considering the >>> opposition mentioned against transaction limits for the rare cases >>> where a very large transaction has already been signed, it seems that >>> this would be worthy of consideration. For the few miners in that >>> situation, it does turn segwit from an optional softfork into a >>> punishing hardfork. >>> >>> I don't think that's a sufficient reason alone to kill the idea, but >>> it should be a concern. >>> >>> Jared >>> >>> On Wed, Jun 7, 2017 at 7:10 AM, Erik Aronesty via bitcoin-dev >>> wrote: >>>> This is, by far, the safest way for miners to quickly defend against a= chain >>>> split, much better than a -bip148 option. This allows miners to defe= nd >>>> themselves, with very little risk, since the defense is only activated= if >>>> the majority of miners do so. I would move for a very rapid deployment= . >>>> Only miners would need to upgrade. Regular users would not have to c= oncern >>>> themselves with this release. >>>> >>>> On Wed, Jun 7, 2017 at 6:13 AM, James Hilliard via bitcoin-dev >>>> wrote: >>>>> >>>>> I think even 55% would probably work out fine simply due to incentive >>>>> structures, once signalling is over 51% it's then clear to miners tha= t >>>>> non-signalling blocks will be orphaned and the rest will rapidly >>>>> update to splitprotection/BIP148. The purpose of this BIP is to reduc= e >>>>> chain split risk for BIP148 since it's looking like BIP148 is going t= o >>>>> be run by a non-insignificant percentage of the economy at a minimum. >>>>> >>>>> On Wed, Jun 7, 2017 at 12:20 AM, Tao Effect w= rote: >>>>> > See thread on replay attacks for why activating regardless of thres= hold >>>>> > is a >>>>> > bad idea [1]. >>>>> > >>>>> > BIP91 OTOH seems perfectly reasonable. 80% instead of 95% makes it = more >>>>> > difficult for miners to hold together in opposition to Core. It giv= es >>>>> > Core >>>>> > more leverage in negotiations. >>>>> > >>>>> > If they don't activate with 80%, Core can release another BIP to re= duce >>>>> > it >>>>> > to 75%. >>>>> > >>>>> > Each threshold reduction makes it both more likely to succeed, but = also >>>>> > increases the likelihood of harm to the ecosystem. >>>>> > >>>>> > Cheers, >>>>> > Greg >>>>> > >>>>> > [1] >>>>> > >>>>> > https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2017-June/0= 14497.html >>>>> > >>>>> > -- >>>>> > Please do not email me anything that you are not comfortable also >>>>> > sharing >>>>> > with the NSA. >>>>> > >>>>> > On Jun 6, 2017, at 6:54 PM, James Hilliard >>>>> > wrote: >>>>> > >>>>> > This is a BIP8 style soft fork so mandatory signalling will be acti= ve >>>>> > after Aug 1st regardless. >>>>> > >>>>> > On Tue, Jun 6, 2017 at 8:51 PM, Tao Effect >>>>> > wrote: >>>>> > >>>>> > What is the probability that a 65% threshold is too low and can all= ow 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 caus= e >>>>> > 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 >>>>> > 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 anot= her >>>>> > option that miners can use to prevent a chain split ahead of the Au= g >>>>> > 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 ahea= d >>>>> > of BIP148 activation by signalling for splitprotection. Any miners >>>>> > already running BIP148 should be encouraged to use splitprotection. >>>>> > >>>>> > 
>>>>> > BIP: splitprotection
>>>>> > Layer: Consensus (soft fork)
>>>>> > Title: User Activated Soft Fork Split Protection
>>>>> > Author: James Hilliard 
>>>>> > Comments-Summary: No comments yet.
>>>>> > Comments-URI:
>>>>> > Status: Draft
>>>>> > Type: Standards Track
>>>>> > Created: 2017-05-22
>>>>> > License: BSD-3-Clause
>>>>> >          CC0-1.0
>>>>> >
>>>>> > >>>>> > =3D=3DAbstract=3D=3D >>>>> > >>>>> > This document specifies a coordination mechanism for a simple major= ity >>>>> > of miners to prevent a chain split ahead of BIP148 activation. >>>>> > >>>>> > =3D=3DDefinitions=3D=3D >>>>> > >>>>> > "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. >>>>> > >>>>> > =3D=3DMotivation=3D=3D >>>>> > >>>>> > The biggest risk of BIP148 is an extended chain split, this BIP >>>>> > provides a way for a simple majority of miners to eliminate that ri= sk. >>>>> > >>>>> > This BIP provides a way for a simple majority of miners to coordina= te >>>>> > 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. Si= nce >>>>> > 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 t= o >>>>> > run BIP148 in order to prevent a chain split. >>>>> > >>>>> > =3D=3DSpecification=3D=3D >>>>> > >>>>> > While this BIP is active, all blocks must set the nVersion header t= op >>>>> > 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. >>>>> > >>>>> > =3D=3DDeployment=3D=3D >>>>> > >>>>> > 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 seg= wit >>>>> > is locked-in. >>>>> > >>>>> > =3D=3D=3D Reference implementation =3D=3D=3D >>>>> > >>>>> > 
>>>>> > // 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) =3D=3D
>>>>> > THRESHOLD_LOCKED_IN);
>>>>> > }
>>>>> >
>>>>> > // SPLITPROTECTION mandatory segwit signalling.
>>>>> > if ( VersionBitsState(pindex->pprev, chainparams.GetConsensus(),
>>>>> > Consensus::DEPLOYMENT_SPLITPROTECTION, versionbitscache) =3D=3D
>>>>> > THRESHOLD_LOCKED_IN &&
>>>>> >    !IsWitnessLockedIn(pindex->pprev, chainparams.GetConsensus()) &&
>>>>> > // Segwit is not locked in
>>>>> >    !IsWitnessEnabled(pindex->pprev, chainparams.GetConsensus()) ) /=
/
>>>>> > and is not active.
>>>>> > {
>>>>> >   bool fVersionBits =3D (pindex->nVersion & VERSIONBITS_TOP_MASK) =
=3D=3D
>>>>> > VERSIONBITS_TOP_BITS;
>>>>> >   bool fSegbit =3D (pindex->nVersion &
>>>>> > VersionBitsMask(chainparams.GetConsensus(),
>>>>> > Consensus::DEPLOYMENT_SEGWIT)) !=3D 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 =3D pindex->GetMedianTimePast();
>>>>> > if ( (nMedianTimePast >=3D 1501545600) &&  // Tue 01 Aug 2017 00:00=
:00 UTC
>>>>> >    (nMedianTimePast <=3D 1510704000) &&  // Wed 15 Nov 2017 00:00:0=
0 UTC
>>>>> >    (!IsWitnessLockedIn(pindex->pprev, chainparams.GetConsensus()) &=
&
>>>>> > // Segwit is not locked in
>>>>> >     !IsWitnessEnabled(pindex->pprev, chainparams.GetConsensus())) )
>>>>> > // and is not active.
>>>>> > {
>>>>> >   bool fVersionBits =3D (pindex->nVersion & VERSIONBITS_TOP_MASK) =
=3D=3D
>>>>> > VERSIONBITS_TOP_BITS;
>>>>> >   bool fSegbit =3D (pindex->nVersion &
>>>>> > VersionBitsMask(chainparams.GetConsensus(),
>>>>> > Consensus::DEPLOYMENT_SEGWIT)) !=3D 0;
>>>>> >   if (!(fVersionBits && fSegbit)) {
>>>>> >       return state.DoS(0, error("ConnectBlock(): relayed block must
>>>>> > signal for segwit, please upgrade"), REJECT_INVALID, "bad-no-segwit=
");
>>>>> >   }
>>>>> > }
>>>>> >
>>>>> > >>>>> > >>>>> > https://github.com/bitcoin/bitcoin/compare/0.14...jameshilliard:spl= itprotection-v0.14.1 >>>>> > >>>>> > =3D=3DBackwards Compatibility=3D=3D >>>>> > >>>>> > This deployment is compatible with the existing "segwit" bit 1 >>>>> > deployment scheduled between midnight November 15th, 2016 and midni= ght >>>>> > 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. >>>>> > >>>>> > =3D=3DRationale=3D=3D >>>>> > >>>>> > Historically we have used IsSuperMajority() to activate soft forks >>>>> > such as BIP66 which has a mandatory signalling requirement for mine= rs >>>>> > once activated, this ensures that miners are aware of new rules bei= ng >>>>> > enforced. This technique can be leveraged to lower the signalling >>>>> > threshold of a soft fork while it is in the process of being deploy= ed >>>>> > 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 approac= h >>>>> > BIP148 activation it may be desirable for a majority of miners to h= ave >>>>> > a method that will ensure that there is no chain split. >>>>> > >>>>> > =3D=3DReferences=3D=3D >>>>> > >>>>> > >>>>> > *[https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2017-Marc= h/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 deploym= ent]] >>>>> > *[[bip-0149.mediawiki|BIP149 Segregated Witness (second deployment)= ]] >>>>> > *[https://bitcoincore.org/en/2016/01/26/segwit-benefits/ Segwit >>>>> > benefits] >>>>> > >>>>> > =3D=3DCopyright=3D=3D >>>>> > >>>>> > This document is dual licensed as BSD 3-clause, and Creative Common= s >>>>> > CC0 1.0 Universal. >>>>> > _______________________________________________ >>>>> > bitcoin-dev mailing list >>>>> > bitcoin-dev@lists.linuxfoundation.org >>>>> > https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev >>>>> > >>>>> > >>>>> > >>>>> _______________________________________________ >>>>> bitcoin-dev mailing list >>>>> bitcoin-dev@lists.linuxfoundation.org >>>>> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev >>>> >>>> >>>> >>>> _______________________________________________ >>>> bitcoin-dev mailing list >>>> bitcoin-dev@lists.linuxfoundation.org >>>> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev >>>>