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📅 Original date posted:2017-11-02 📝 Original message:Just ...

2023-06-07T18:07:23Z

In reply to nevent1q…9nra
_________________________

📅 Original date posted:2017-11-02
📝 Original message:Just going to throw in my support for a POW change, not any particular implementation, but the idea.

Bitcoin is technically owned by China now. That's not acceptable.

- Greg

--
Please do not email me anything that you are not comfortable also sharing with the NSA.

> On Oct 31, 2017, at 10:48 PM, Devrandom via bitcoin-dev <bitcoin-dev at lists.linuxfoundation.org <mailto:bitcoin-dev at lists.linuxfoundation.org>> wrote:
>
> Hi all,
>
> Feedback is welcome on the draft below. In particular, I want to see if there is interest in further development of the idea and also interested in any attack vectors or undesirable dynamics.
>
> (Formatted version available here: https://github.com/devrandom/btc-papers/blob/master/aux-pow.md <https://github.com/devrandom/btc-papers/blob/master/aux-pow.md>; )
>
> # Soft-fork Introduction of a New POW
>
> ## Motivation:
>
> - Mitigate mining centralization pressures by introducing a POW that does not have economies of scale
> - Introduce an intermediary confirmation point, reducing the impact of mining power fluctuations
>
> Note however that choice of a suitable POW will require deep analysis. Some pitfalls include: botnet mining, POWs that seem ASIC resistant but are not, unexpected/covert optimization.
>
> In particular, unexpected/covert optimizations, such as ASCIBOOST, present a potential centralizing and destabilizing force.
>
> ## Design
>
> ### Aux POW intermediate block
>
> Auxiliary POW blocks are introduced between normal blocks - i.e. the chain alternates between the two POWs.
> Each aux-POW block points to the previous normal block and contains transactions just like a normal block.
> Each normal block points to the previous aux-POW block and must contain all transactions from the aux-POW block.
> Block space is not increased.
>
> The new intermediate block and the pointers are introduced via a soft-fork restriction.
>
> ### Reward for aux POW miners
>
> The reward for the aux POW smoothly increases from zero to a target value (e.g. 1/2 of the total reward) over time.
> The reward is transferred via a soft-fork restriction requiring a coinbase output to an address published in the
> aux-POW block.
>
> ### Aux POW difficulty adjustment
>
> Difficulty adjustments remain independent for the two POWs.
>
> The difficulty of the aux POW is adjusted based on the average time between normal block found
> to aux block found.
>
> Further details are dependent on the specific POW.
>
> ### Heaviest chain rule change
>
> This is a semi-hard change, because non-upgraded nodes can get on the wrong chain in case of attack. However,
> it might be possible to construct an alert system that notifies non-upgraded nodes of an upcoming rule change.
> All blocks are still valid, so this is not a hardforking change.
>
> The heaviest chain definition changes from sum of `difficulty` to sum of:
>
> mainDifficulty ^ x * auxDifficulty ^ y
>
> where we start at:
>
> x = 1; y = 0
>
> and end at values of x and y that are related to the target relative rewards. For example, if the target rewards
> are equally distributed, we will want ot end up at:
>
> x = 1/2; y = 1/2
>
> so that both POWs have equal weight. If the aux POW is to become dominant, x should end small relative to y.
>
>
> ## Questions and Answers
>
> - What should be the parameters if we want the aux POW to have equal weight? A: 1/2 of the reward should be transferred
> to aux miners and x = 1/2, y = 1/2.
>
> - What should be the parameters if we want to deprecate the main POW? A: most of the reward should be transferred to
> aux miners and x = 0, y = 1. The main difficulty will tend to zero, and aux miners will just trivially generate the
> main block immediately after finding an aux block, with identical content.
>
> - Wasted bandwidth to transfer transactions twice? A: this can be optimized by skipping transactions already
> transferred.
>
> - Why would miners agree to soft-fork away some of their reward? A: they would agree if they believe that
> the coins will increase in value due to improved security properties.
>
> ## Open Questions
>
> - After a block of one type is found, we can naively assume that POW will become idle while a block of the other type is being mined. In practice, the spare capacity can be used to find alternative ("attacking") blocks or mine other coins. Is that a problem?
> - Is selfish mining amplified by this scheme for miners that have both types of hardware?
>
> ## POW candidates
>
> - SHA256 (i.e. use same POW, but introduce an intermediate block for faster confirmation)
> - Proof of Space and Time (Bram Cohen)
> - Equihash
> - Ethash
>
> ## Next Steps
>
> - evaluate POW candidates
> - evaluate difficulty adjustment rules
> - simulate miner behavior to identify if there are incentives for detrimental behavior patterns (e.g. block withholding / selfish mining)
> - Protocol details
>
> ## Credits
>
> Bram Cohen came up with a similar idea back in March:
> https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2017-March/013744.html <https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2017-March/013744.html>_______________________________________________
> bitcoin-dev mailing list
> bitcoin-dev at lists.linuxfoundation.org <mailto:bitcoin-dev at lists.linuxfoundation.org>
> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev

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📅 Original date posted:2017-10-09 📝 Original message:Dear ...

2023-06-07T18:06:58Z

In reply to nevent1q…ngvr
_________________________

📅 Original date posted:2017-10-09
📝 Original message:Dear list,

In previous arguments over Drivechain (and Drivechain-like proposals) I promised that better scaling proposals — that do not sacrifice Bitcoin's security — would come along.

I planned to do a detailed writeup, but have decided to just send off this email with what I have, because I'm unlikely to have time to write up a detailed proposal.

The idea is very simple, and I'm sure others have mentioned either exactly it, or similar ideas (e.g. burning coins) before.

This is a generic sharding protocol for all blockchains, including Bitcoin.

Users simply say: "My coins on Chain A are going to be sent to Chain B".

Then they burn the coins on Chain A, and create a minting transaction on Chain B. The details of how to ensure that coins do not get lost needs to be worked out, but I'm fairly certain the folks on this list can figure out those details.

- Thin clients, nodes, and miners, can all very easily verify that said action took place, and therefore accept the "newly minted" coins on B as valid.
- Users client software now also knows where to look for the other coins (if for some reason it needs to).

This doesn't even need much modification to the Bitcoin protocol as most of the verification is done client-side.

It is fully decentralized, and there's no need to give our ownership of our coins to miners to get scale.

My sincere apologies if this has been brought up before (in which case, I would be very grateful for a link to the proposal).

Cheers,
Greg Slepak

--
Please do not email me anything that you are not comfortable also sharing with the NSA.

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📅 Original date posted:2017-10-09 📝 Original message:Dear ...

2023-06-07T18:06:58Z

In reply to nevent1q…u9np
_________________________

📅 Original date posted:2017-10-09
📝 Original message:Dear list,

In previous arguments over Drivechain (and Drivechain-like proposals) I promised that better scaling proposals — that do not sacrifice Bitcoin's security — would come along.

I planned to do a detailed writeup, but have decided to just send off this email with what I have, because I'm unlikely to have time to write up a detailed proposal.

The idea is very simple (and by no means novel*), and I'm sure others have mentioned either exactly it, or similar ideas (e.g. burning coins) before.

This is a generic sharding protocol for all blockchains, including Bitcoin.

Users simply say: "My coins on Chain A are going to be sent to Chain B".

Then they burn the coins on Chain A, and create a minting transaction on Chain B. The details of how to ensure that coins do not get lost needs to be worked out, but I'm fairly certain the folks on this list can figure out those details.

- Thin clients, nodes, and miners, can all very easily verify that said action took place, and therefore accept the "newly minted" coins on B as valid.
- Users client software now also knows where to look for the other coins (if for some reason it needs to).

This doesn't even need much modification to the Bitcoin protocol as most of the verification is done client-side.

It is fully decentralized, and there's no need to give our ownership of our coins to miners to get scale.

My sincere apologies if this has been brought up before (in which case, I would be very grateful for a link to the proposal).

Cheers,
Greg Slepak

* This idea is similar in spirit to Interledger.

--
Please do not email me anything that you are not comfortable also sharing with the NSA.

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📅 Original date posted:2017-06-07 📝 Original message:See ...

2023-06-07T18:02:34Z

In reply to nevent1q…xlwz
_________________________

📅 Original date posted:2017-06-07
📝 Original message: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 <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 <james.hilliard1 at gmail.com <mailto:james.hilliard1 at gmail.com>> 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 <contact at taoeffect.com <mailto:contact at 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 at lists.linuxfoundation.org <mailto:bitcoin-dev at lists.linuxfoundation.org>> wrote:
>>
>> Due to the proposed calendar(https://segwit2x.github.io/ <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 at gmail.com <mailto:james.hilliard1 at 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 <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 at lists.linuxfoundation.org
>> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
>>
>>

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📅 Original date posted:2017-06-06 📝 Original message:What ...

2023-06-07T18:02:31Z

In reply to nevent1q…3tq8
_________________________

📅 Original date posted:2017-06-06
📝 Original message: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 at lists.linuxfoundation.org <mailto:bitcoin-dev at lists.linuxfoundation.org>> wrote:
>
> Due to the proposed calendar(https://segwit2x.github.io/ <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 at gmail.com <mailto:james.hilliard1 at 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 <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 <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 <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 <https://bitcoincore.org/en/2016/01/26/segwit-benefits/%20Segwit%20benefits>;]
>
> ==Copyright==
>
> This document is dual licensed as BSD 3-clause, and Creative Commons
> CC0 1.0 Universal.
> _______________________________________________
> bitcoin-dev mailing list
> bitcoin-dev at lists.linuxfoundation.org <mailto:bitcoin-dev at lists.linuxfoundation.org>
> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev <https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev>;

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📅 Original date posted:2017-06-06 📝 Original message:Hey ...

2023-06-07T18:02:24Z

In reply to nevent1q…77g7
_________________________

📅 Original date posted:2017-06-06
📝 Original message:Hey Greg,

It wasn't my intention to insult anyone (a bit defensive?).

Maybe this is yet another example of a recurring criticism of Core: that core doesn't community these issues very well to journalists / reports / media / community outside of this list.

Because outside of this list it's been all about those 148 coins, and almost zero mention of replay attacks.

> BIP149 is arguably something of another matter in particular because
> it has a time-frame that allows dealing with replay and other issues--
> and particularly because it has a time-frame that can allow for the
> avoidance of a meaningful fork at all.

Are there other, more reasonable / feasible ways of addressing replay attacks in Bitcoin / BIP149 scenario?

Cheers,
Greg

--
Please do not email me anything that you are not comfortable also sharing with the NSA.

> On Jun 6, 2017, at 4:02 PM, Gregory Maxwell <greg at xiph.org <mailto:greg at xiph.org>> wrote:
>
> On Tue, Jun 6, 2017 at 10:39 PM, Tao Effect via bitcoin-dev
> <bitcoin-dev at lists.linuxfoundation.org <mailto:bitcoin-dev at lists.linuxfoundation.org>> wrote:
>> I believe the severity of replay attacks is going unvoiced and is not
>> understood within the bitcoin community because of their lack of experience
>> with them.
>
> Please don't insult our community-- the issues with replay were
> pointed out by us to Ethereum in advance and were cited specifically
> in prior hardfork discussions long before Ethereum started editing
> their ledger for the economic benefit of its centralized
> administrators.
>
> The lack of extensive discussion on these issues you're seeing is
> rather symptomatic of engineers that take stability seriously not
> taking BIP148 seriously; not symptomatic of people not knowing about
> them. The same concerns also applies to all these HF proposals (which
> for some reason you don't mention), arguably even stronger. The same
> basic pattern exists: There are people that just don't care about the
> technical issues who have made up their minds, and so you don't see
> technical discussion. Those people who do see the issues already
> called out the proposals as being ill-advised. Replay isn't even the
> largest of the technical issues (network partitioning, for example, is
> a much larger one).
>
> BIP149 is arguably something of another matter in particular because
> it has a time-frame that allows dealing with replay and other issues--
> and particularly because it has a time-frame that can allow for the
> avoidance of a meaningful fork at all.

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📅 Original date posted:2017-06-06 📝 Original message:This ...

2023-06-07T18:02:23Z

In reply to nevent1q…s5uv
_________________________

📅 Original date posted:2017-06-06
📝 Original message:This is just me putting in my formal objection to BIP148 and BIP149 based on my experience with the ETH/ETC hard fork and involvement in that drama.

First, it's important to note that ETC/ETH HF is a very different situation from BIP148 and all other soft-forks. To those on this mailing list, the reasons should be self-evident (one results in two incompatible chains, the other doesn't).

However, replay attacks are common to both possibilities (i.e. when BIP148 has <51% hash power).

I believe the severity of replay attacks is going unvoiced and is not understood within the bitcoin community because of their lack of experience with them.

I further believe that replay attacks are the #1 issue with BIP148, BIP149, etc., superseding wipeout attacks in severity.

These are not baseless beliefs, they're born out of experience and I think anyone will reach the same conclusion upon study.

In a nutshell, replay attacks mean that all talk of there being potentially "two coins" as a result of BIP148 is basically nonsense.

Replay attacks effectively eliminate that possibility.

When users go to "sell their legacy coins", they've just sold their 148 coins, and vice versa.

Both of the coin-splitting techniques given so far by the proponents BIP148 are also untenable:

- Double-spending to self with nLockTime txns is insanely complicated, risky, not guaranteed to work, extremely time consuming, and would likely result in a massive increase in backlogged transactions and increased fees.

- Mixing with 148 coinbase txns destroys fungibility.

Without a coin, there is no real threat from BIP148. Without that threat, there is no point to BIP148, and the miners know this.

These and other concerns are outlined and explained in more detail in this conversation I had yesterday with John Light:

https://www.youtube.com/watch?v=33rL3-p8cPw <https://www.youtube.com/watch?v=33rL3-p8cPw>;

Cheers,
Greg Slepak

--
Please do not email me anything that you are not comfortable also sharing with the NSA.

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📅 Original date posted:2017-06-06 📝 Original message:This ...

2023-06-07T18:02:23Z

In reply to nevent1q…ren3
_________________________

📅 Original date posted:2017-06-06
📝 Original message:This is just me putting in my formal objection to BIP148 and BIP149 based on my experience with the ETH/ETC hard fork and involvement in that drama.

First, it's important to note that ETC/ETH HF is a very different situation from BIP148 and all other soft-forks. To those on this mailing list, the reasons should be self-evident (one results in two incompatible chains, the other doesn't).

However, replay attacks are common to both possibilities (i.e. when BIP148 has <51% hash power).

I believe the severity of replay attacks is going unvoiced and is not understood within the bitcoin community because of their lack of experience with them.

I further believe that replay attacks are the #1 issue with BIP148, BIP149, etc., superseding wipeout attacks in severity.

These are not baseless beliefs, they're born out of experience and I think anyone will reach the same conclusion upon study.

In a nutshell, replay attacks mean that all talk of there being potentially "two coins" as a result of BIP148 is basically nonsense.

Replay attacks effectively eliminate that possibility.

When users go to "sell their legacy coins", they've just sold their 148 coins, and vice versa.

Both of the coin-splitting techniques given so far by the proponents BIP148 are also untenable:

- Double-spending to self with nLockTime txns is insanely complicated, risky, not guaranteed to work, extremely time consuming, and would likely result in a massive increase in backlogged transactions and increased fees.

- Mixing with 148 coinbase txns destroys fungibility.

Without a coin, there is no real threat from BIP148. Without that threat, there is no point to BIP148, and the miners know this.

These and other concerns are outlined and explained in more detail in this conversation I had yesterday with John Light:

https://www.youtube.com/watch?v=33rL3-p8cPw <https://www.youtube.com/watch?v=33rL3-p8cPw>;

Cheers,
Greg Slepak

--
Please do not email me anything that you are not comfortable also sharing with the NSA.

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