Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 4ED1FBC5 for ; Wed, 7 Jun 2017 14:10:52 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.7.6 Received: from mail-qt0-f170.google.com (mail-qt0-f170.google.com [209.85.216.170]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 0D7818E for ; Wed, 7 Jun 2017 14:10:49 +0000 (UTC) Received: by mail-qt0-f170.google.com with SMTP id u19so8020496qta.3 for ; Wed, 07 Jun 2017 07:10:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:sender:in-reply-to:references:from:date:message-id :subject:to:cc; bh=WS8Wpgr9R3DokMbKWKk9p94IEOrh+vqmcJqBg5QVUPk=; b=GstHcURphHe+MaiMpgHJoT1g0pdbyTo1f/jahuOyqSJR95VyorHe7IkCmuGz4rUEpn B1HE5e0iC7B8+UniUCQLpHjO/czjpYvH+JgbuXdISbXMyPI3I6Zg9Kk3lxJZPbcLjw2l Rbs2A89X7g+PSXBBnBzpye6n3/DgPWFA1vkkzzp7Ylp6R/Spgt95SV0yuEapc4/UajRu IjSkLejJaxQMReEWueDiYbkwWMrAuklyxdFhtIkUv4nOMPYaxhAEu/fLEhZwiGFcvUF/ 6dz6mGsNk/7VAUR3JY6+GU4aU3Qe0vpy7zutz+AM1lLZkcM0SBWz8bVn0WJByReMFSvS AgDA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:sender:in-reply-to:references:from :date:message-id:subject:to:cc; bh=WS8Wpgr9R3DokMbKWKk9p94IEOrh+vqmcJqBg5QVUPk=; b=aUdKmWwjOqjU9DfiMroFCYBStzpiiDAlq/oo3Y3MwwlskZm0erTg2RPYF3dB+Kuci5 edh4DugFQLNXyTnqq4g9rXF6nZa7bRHt2W/JjNWauTPZwQrx2+2rIL5Sv3XqOF8+Xx77 YHc+Sr8VgJ4YQyVhOvD8OwW7xcF+iyKXVrJ5g9eRu2K5H+/j7QHScxzDKU0K8syIdW2l 7LhiI2NvuzRVV6lVwc7X7/YZB3KtrdMpTk4Svh0byEx2mK3/b86/dG05Jjzb0Mrwemz5 6z5ClQ0X8BTi1K6pH0EjVEv+ppLm8sWnNYweZTAlTG+kDy+vi2p3QNV2Bw45R+ATO97T Y+cA== X-Gm-Message-State: AKS2vOzM3HdZHxrYW9NEA+Xv6KzaZr2takhR25Ty0GAy2oW4OMHh4tBt KX8gokd/m0MY2tS87noq04zvJCX+cw== X-Received: by 10.200.43.217 with SMTP id n25mr40829842qtn.190.1496844648661; Wed, 07 Jun 2017 07:10:48 -0700 (PDT) MIME-Version: 1.0 Sender: earonesty@gmail.com Received: by 10.237.48.102 with HTTP; Wed, 7 Jun 2017 07:10:48 -0700 (PDT) In-Reply-To: References: <0CDEF5A2-0BAF-46E4-8906-39D4724AF3F2@taoeffect.com> From: Erik Aronesty Date: Wed, 7 Jun 2017 10:10:48 -0400 X-Google-Sender-Auth: iIPRHkp6eTn_O8eDNios1NyVeuM Message-ID: To: James Hilliard Content-Type: multipart/alternative; boundary="001a1140e91491472e05515f4dbf" X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, FREEMAIL_FROM, HTML_MESSAGE, RCVD_IN_DNSWL_NONE 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: Wed, 07 Jun 2017 14:13:11 +0000 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 14:10:52 -0000 --001a1140e91491472e05515f4dbf Content-Type: text/plain; charset="UTF-8" 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 defend 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 concern themselves with this release. On Wed, Jun 7, 2017 at 6:13 AM, James Hilliard via bitcoin-dev < bitcoin-dev@lists.linuxfoundation.org> 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 that > non-signalling blocks will be orphaned and the rest will rapidly > update to splitprotection/BIP148. The purpose of this BIP is to reduce > chain split risk for BIP148 since it's looking like BIP148 is going to > be run by a non-insignificant percentage of the economy at a minimum. > > On Wed, Jun 7, 2017 at 12:20 AM, Tao Effect wrote: > > See thread on replay attacks for why activating regardless of threshold > 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 gives > Core > > more leverage in negotiations. > > > > If they don't activate with 80%, Core can release another BIP to reduce > 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/014497.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 active > > 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 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 > > 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. > > > > 
> > 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
> >
> > > > ==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 === > > > > 
> > // 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");
> >   }
> > }
> >
> > > > 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 > > > > > > > _______________________________________________ > bitcoin-dev mailing list > bitcoin-dev@lists.linuxfoundation.org > https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev > --001a1140e91491472e05515f4dbf Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
This is, by far, the safest way for miners to quickly= defend against a chain split, much better than a -bip148 option.=C2=A0=C2= =A0 This allows miners to defend themselves, with very little risk, since t= he defense is only activated if the majority of miners do so. I would move = for a very rapid deployment.=C2=A0=C2=A0 Only miners would need to upgrade.= =C2=A0=C2=A0 Regular users would not have to concern themselves with this r= elease.

On Wed, Jun 7, 2017 at 6:13 AM, James Hilliard via bitcoin-dev <bitcoin-dev@lists.linuxfoundation.org> 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 that<= br> non-signalling blocks will be orphaned and the rest will rapidly
update to splitprotection/BIP148. The purpose of this BIP is to reduce
chain split risk for BIP148 since it's looking like BIP148 is going to<= br> be run by a non-insignificant percentage of the economy at a minimum.

On Wed, Jun 7, 2017 at 12:20 AM, Tao Effect <contact@taoeffect.com> wrote:
> See thread on replay attacks for why activating regardless of threshol= d is a
> bad idea [1].
>
> BIP91 OTOH seems perfectly reasonable. 80% instead of 95% makes it mor= e
> difficult for miners to hold together in opposition to Core. It gives = Core
> more leverage in negotiations.
>
> If they don't activate with 80%, Core can release another BIP to r= educe it
> to 75%.
>
> Each threshold reduction makes it both more likely to succeed, but als= o
> increases the likelihood of harm to the ecosystem.
>
> Cheers,
> Greg
>
> [1]
> https://lists.linu= xfoundation.org/pipermail/bitcoin-dev/2017-June/014497.html >
> --
> Please do not email me anything that you are not comfortable also shar= ing
> with the NSA.
>
> On Jun 6, 2017, at 6:54 PM, James Hilliard <james.hilliard1@gmail.com>
> wrote:
>
> This is a BIP8 style soft fork so mandatory signalling will be active<= br> > 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 bef= ore the
> deadline, and brought online immediately after, creating potential hav= oc?
>
> (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 shar= ing
> with the NSA.
>
> On Jun 6, 2017, at 5:56 PM, James Hilliard via bitcoin-dev
> <bitcoin-d= ev@lists.linuxfoundation.org> wrote:
>
> Due to the proposed calendar(https://segwit2x.github.io/) f= or 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<= br> > 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
>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 CC0-1.0
> </pre>
>
> =3D=3DAbstract=3D=3D
>
> This document specifies a coordination mechanism for a simple majority=
> of miners to prevent a chain split ahead of BIP148 activation.
>
> =3D=3DDefinitions=3D=3D
>
> "existing segwit deployment" refer to the BIP9 "segwit&= quot; 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 risk.=
>
> This BIP provides a way for a simple majority of miners to coordinate<= br> > 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.
>
> =3D=3DSpecification=3D=3D
>
> While this BIP is active, all blocks must set the nVersion header top<= br> > 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 segwit=
> is locked-in.
>
> =3D=3D=3D Reference implementation =3D=3D=3D
>
> <pre>
> // Check if Segregated Witness is Locked In
> bool IsWitnessLockedIn(const CBlockIndex* pindexPrev, const
> Consensus::Params& params)
> {
>=C2=A0 =C2=A0LOCK(cs_main);
>=C2=A0 =C2=A0return (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 &&
>=C2=A0 =C2=A0 !IsWitnessLockedIn(pindex->pprev, chainparams.Get= Consensus()) &&
> // Segwit is not locked in
>=C2=A0 =C2=A0 !IsWitnessEnabled(pindex->pprev, chainparams.GetC= onsensus()) ) //
> and is not active.
> {
>=C2=A0 =C2=A0bool fVersionBits =3D (pindex->nVersion & VERSIONBI= TS_TOP_MASK) =3D=3D
> VERSIONBITS_TOP_BITS;
>=C2=A0 =C2=A0bool fSegbit =3D (pindex->nVersion &
> VersionBitsMask(chainparams.GetConsensus(),
> Consensus::DEPLOYMENT_SEGWIT)) !=3D 0;
>=C2=A0 =C2=A0if (!(fVersionBits && fSegbit)) {
>=C2=A0 =C2=A0 =C2=A0 =C2=A0return state.DoS(0, error("ConnectBlock= (): relayed block must
> signal for segwit, please upgrade"), REJECT_INVALID, "bad-no= -segwit");
>=C2=A0 =C2=A0}
> }
>
> // BIP148 mandatory segwit signalling.
> int64_t nMedianTimePast =3D pindex->GetMedianTimePast();
> if ( (nMedianTimePast >=3D 1501545600) &&=C2=A0 // Tue 01 A= ug 2017 00:00:00 UTC
>=C2=A0 =C2=A0 (nMedianTimePast <=3D 1510704000) &&=C2=A0 // = Wed 15 Nov 2017 00:00:00 UTC
>=C2=A0 =C2=A0 (!IsWitnessLockedIn(pindex->pprev, chainparams.Ge= tConsensus()) &&
> // Segwit is not locked in
>=C2=A0 =C2=A0 =C2=A0!IsWitnessEnabled(pindex->pprev, chainparam= s.GetConsensus())) )
> // and is not active.
> {
>=C2=A0 =C2=A0bool fVersionBits =3D (pindex->nVersion & VERSIONBI= TS_TOP_MASK) =3D=3D
> VERSIONBITS_TOP_BITS;
>=C2=A0 =C2=A0bool fSegbit =3D (pindex->nVersion &
> VersionBitsMask(chainparams.GetConsensus(),
> Consensus::DEPLOYMENT_SEGWIT)) !=3D 0;
>=C2=A0 =C2=A0if (!(fVersionBits && fSegbit)) {
>=C2=A0 =C2=A0 =C2=A0 =C2=A0return state.DoS(0, error("ConnectBlock= (): relayed block must
> signal for segwit, please upgrade"), REJECT_INVALID, "bad-no= -segwit");
>=C2=A0 =C2=A0}
> }
> </pre>
>
> https://= github.com/bitcoin/bitcoin/compare/0.14...jameshilliard:splitprot= ection-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 midnight=
> November 15th, 2017. This deployment is also compatible with the
> existing BIP148 deployment. This BIP is compatible with BIP91 only if<= br> > 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 miners<= br> > once activated, this ensures that miners are aware of new rules being<= br> > enforced. This technique can be leveraged to lower the signalling
> threshold of a soft fork while it is in the process of being deployed<= br> > 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&= quot;
> deployment, this BIP can cause the existing "segwit" deploym= ent 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.
>
> =3D=3DReferences=3D=3D
>
> *[https://lists.<= wbr>linuxfoundation.org/pipermail/bitcoin-dev/2017-March/013714.h= tml
> Mailing list discussion]
> *[https://github.com/bit= coin/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 malleabi= lity]]
> *[[bip-0148.mediawiki|BIP148 Mandatory activation of segwit deployment= ]]
> *[[bip-0149.mediawiki|BIP149 Segregated Witness (second deployment)]]<= br> > *[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 Commons > CC0 1.0 Universal.
> _______________________________________________
> bitcoin-dev mailing list
> bitcoin-dev@l= ists.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

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