From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id D466FC6A for ; Wed, 7 Jun 2017 21:21:31 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.7.6 Received: from mail-ot0-f173.google.com (mail-ot0-f173.google.com [74.125.82.173]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id D364916C for ; Wed, 7 Jun 2017 21:21:30 +0000 (UTC) Received: by mail-ot0-f173.google.com with SMTP id t31so13843979ota.1 for ; Wed, 07 Jun 2017 14:21:30 -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=qhKSuYzl5zGdblT2eyMiVnG4+f51x1pdkbrevdPvBsA=; b=IUF6j1fxNO+w6ZL2EPYpKTLkvxEWvV8i03hWbXTGghkfeE9pcPOpMDYergcTxzkJGq loAXi5Qnw4hVfDboHL5Gz792qo1vzOqEvX20KGj7uvAAxAnf8J5QitQxB3yY6S4g7xE4 /Rl346EMquY2UfNfg/ULXEr+Fg8fxJRCQgrP2eQ9XUnIxtDtNrdlp64ZA3RZD7NLdrYQ 9xHHMcrRep6EijsRvlbea2ZymQA8WyTMLnCLYLoma5Gl8SGT4/Xps2d4NKmvhmPWI7D1 +qWuGW8irbd6cyjRTe+UiUKbh/nyXquE4LDx3MzL2T+Qc9bjGi9lOscr7J2a06bBkyju AXhQ== 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=qhKSuYzl5zGdblT2eyMiVnG4+f51x1pdkbrevdPvBsA=; b=YxeXjK0UOibqkix5Qs3sN3AMGB22mJTyI5POYKfuw1QnO9HAFO4nskarVCvHtF1Agg XVBA89K+vHf5zoSQHlvS+wYwNViyDAVTI0AFNHGQ0VD/mfA0nAXnKxEFSV6JvwBxlibE vK6XTWfi27eUsx5sPvtkoSNX51lxTv6bTUC1/3ASNOwlQgZOKy2tyAgufaWrzxv8ZPEJ OjrCo8GIuYzvQ3Yf4Nq+hWgjXds2tulKopnvmhBl3kl/p3J8ArzKO/ifNCtxFLZnLbtp roWegwME1yE9s/b/0xHffYklcHHo0f9cRwqwkzHiELi5cDnnx9MfXqqfF1jYupQeA9qy +P+g== X-Gm-Message-State: AODbwcC5Dn5djMsF3z5B8tZLPqdODUA0LLYMzCQvgyqNqjPCjpjOLynn KQuvV5DFgbjAnYrbnn83SqYGqPS0q444 X-Received: by 10.157.7.164 with SMTP id 33mr10444510oto.120.1496870489954; Wed, 07 Jun 2017 14:21:29 -0700 (PDT) MIME-Version: 1.0 Received: by 10.182.224.230 with HTTP; Wed, 7 Jun 2017 14:21:29 -0700 (PDT) In-Reply-To: References: <0CDEF5A2-0BAF-46E4-8906-39D4724AF3F2@taoeffect.com> From: James Hilliard Date: Wed, 7 Jun 2017 16:21:29 -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 21:21:31 -0000 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 w= rote: >> This is, by far, the safest way for miners to quickly defend against a c= hain split, much better than a -bip148 option. This allows miners to defe= nd themselves, with very little risk, since the defense is only activated i= f 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 conce= rn 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 c= hain >> split, much better than a -bip148 option. This allows miners to defend >> themselves, with very little risk, since the defense is only activated i= f >> 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. >> >> 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 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 wro= te: >>> > See thread on replay attacks for why activating regardless of thresho= ld >>> > is a >>> > bad idea [1]. >>> > >>> > BIP91 OTOH seems perfectly reasonable. 80% instead of 95% makes it mo= re >>> > 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 redu= ce >>> > it >>> > to 75%. >>> > >>> > Each threshold reduction makes it both more likely to succeed, but al= so >>> > increases the likelihood of harm to the ecosystem. >>> > >>> > Cheers, >>> > Greg >>> > >>> > [1] >>> > >>> > https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2017-June/014= 497.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 anothe= r >>> > 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
>>> >
>>> > >>> > =3D=3DAbstract=3D=3D >>> > >>> > This document specifies a coordination mechanism for a simple majorit= y >>> > 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 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. Sinc= e >>> > 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 >>> > 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 it= s >>> > own signalling threshold. This BIP will cease to be active when segwi= t >>> > 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 00:00:0=
0 UTC
>>> >    (nMedianTimePast <=3D 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 =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:split= protection-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 midnigh= t >>> > 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 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 hav= e >>> > a method that will ensure that there is no chain split. >>> > >>> > =3D=3DReferences=3D=3D >>> > >>> > >>> > *[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-L= 1283 >>> > 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 deploymen= t]] >>> > *[[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 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 >> >> >> >> _______________________________________________ >> bitcoin-dev mailing list >> bitcoin-dev@lists.linuxfoundation.org >> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev >>