summaryrefslogtreecommitdiff
path: root/9e/9e4016749f0314af1180c6bbb84fa16f34091e
blob: ce67c5c932000eba728a36f1f93ca722da4509fd (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
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
>
>