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 00B68721 for ; Tue, 23 May 2017 20:42:49 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.7.6 Received: from mail-oi0-f50.google.com (mail-oi0-f50.google.com [209.85.218.50]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 10BC51AE for ; Tue, 23 May 2017 20:42:47 +0000 (UTC) Received: by mail-oi0-f50.google.com with SMTP id l18so217290798oig.2 for ; Tue, 23 May 2017 13:42:47 -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=LUwFdzxNwy735+9DJO6Ybx3uHZMlQzUQFG561J7DmI8=; b=Y6ZfSY7r4RVvIjLKqaWHv0xSJzcUKS34/5sNnkCpzBG2tDg201oXv+Bw4/4tZld8Ot 0B2KXdqCP+/UOSSZ2uLqDvlor7lmjdqv47QIJOHpWOPUxUd5mSAwzn9L0ANjDlcdNQpo iSP3DM+TXGfJy9lUxAVXa50psQv+7D5KK6VvMN/fK0N5UDQL29dG+b89J+P6uMJj7TWP KWnuSEXkrOOyh/q9jW6B6DE4RCHlqgw9aj6LNDp0qLW3RaTse4ahnhSiU31uZKdC+mxr /5a07jFIQA+kPJK+jmls2pva5qyRx1iQkvUMq+vnARI4uc1+TyL0ipljKqxiIoeY3a87 4LwQ== 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=LUwFdzxNwy735+9DJO6Ybx3uHZMlQzUQFG561J7DmI8=; b=sve8RtQpyMSWkux6fuLvpVm/Y7cXRr5n/uc8hmu/dSPN11terWEnjAn5ReD06qGQHw dcn2X5BVYXPyXkGjU5b1RwTRTZ0OZSLm0br9SSe/U4Pemis0gpyiLJ2T3Qc+bd88g6k4 UuSP4mpZnPxMzzLT1QzJJ+JegmPGp5sUYWkyrhrMtTe6m6tjNcwsVpsGAaEbkqplSXPU Yg7ucSiskMBRl3rjgykSJTSH6xPGbbSHOR2dsrt/6w5nADSWzDLcaCHnLUuSqd5WPhV+ GACtc7VWZNYL7hZCcEo8WJKoUHurNXT+lXoaTekpVyFZy25aMrMZjPFuxgFRP4+cPORb i0Gg== X-Gm-Message-State: AODbwcCjKUGOuFw0sNvERKAesbaatBE9Rb2JRd7kNY2PP/NTTg7UP6Bz 6ZC35rZ7he6pb8yS7OxY7ZCTd644aA== X-Received: by 10.202.85.70 with SMTP id j67mr16262097oib.160.1495572167245; Tue, 23 May 2017 13:42:47 -0700 (PDT) MIME-Version: 1.0 Received: by 10.182.130.166 with HTTP; Tue, 23 May 2017 13:42:46 -0700 (PDT) In-Reply-To: References: From: James Hilliard Date: Tue, 23 May 2017 16:42:46 -0400 Message-ID: To: Andrew Chow Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-1.2 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_ENVFROM_END_DIGIT,FREEMAIL_FROM, RCVD_IN_DNSWL_NONE,RCVD_IN_SORBS_SPAM 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] Reduced signalling threshold activation of existing segwit deployment 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: Tue, 23 May 2017 20:42:49 -0000 That is incorrect, it is compatible with the current segwit implementation because it triggers a mandatory signalling period that will activate segwit on existing nodes. On Tue, May 23, 2017 at 4:39 PM, Andrew Chow via bitcoin-dev wrote: > Hi James, > > From what I understand, this proposal is incompatible with the current > segwit implementation with regards to the NODE_WITNESS service bit. I > believe it could cause network partitioning if the service bit is not > changed. > > Andrew > > > On 5/22/2017 6:40 PM, James Hilliard via bitcoin-dev wrote: >> I would like to propose an implementation that accomplishes the first >> part of the Barry Silbert proposal independently from the second: >> >> "Activate Segregated Witness at an 80% threshold, signaling at bit 4" >> in a way that >> >> The goal here is to minimize chain split risk and network disruption >> while maximizing backwards compatibility and still providing for rapid >> activation of segwit at the 80% threshold using bit 4. >> >> By activating segwit immediately and separately from any HF we can >> scale quickly without risking a rushed combined segwit+HF that would >> almost certainly cause widespread issues. >> >> Draft proposal: >> https://github.com/jameshilliard/bips/blob/bip-segsignal/bip-segsignal.mediawiki >> >> Proposal text: >> 
>>   BIP: segsignal
>>   Layer: Consensus (soft fork)
>>   Title: Reduced signalling threshold activation of existing segwit deployment
>>   Author: James Hilliard 
>>   Status: Draft
>>   Type: Standards Track
>>   Created: 2017-05-22
>>   License: BSD-3-Clause
>>            CC0-1.0
>>
>> >> ==Abstract== >> >> This document specifies a method to activate the existing BIP9 segwit >> deployment with a majority hashpower less than 95%. >> >> ==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== >> >> Segwit increases the blocksize, fixes transaction malleability, and >> makes scripting easier to upgrade as well as bringing many other >> [https://bitcoincore.org/en/2016/01/26/segwit-benefits/ benefits]. >> >> This BIP provides a way for a simple majority of miners to coordinate >> activation of the existing segwit deployment with less than 95% >> hashpower. For a number of reasons a complete redeployment of segwit >> is difficulty to do until the existing deployment expires. This is due >> to 0.13.1+ having many segwit related features active already, >> including all the P2P components, the new network service flag, the >> witness-tx and block messages, compact blocks v2 and preferential >> peering. A redeployment of segwit will need to redefine all these >> things and doing so before expiry would greatly complicate testing. >> >> ==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 a "version bits" with an 80%(this can be >> adjusted if desired) activation threshold BIP9 with the name >> "segsignal" and using bit 4. >> >> This BIP will have a start time of midnight June 1st, 2017 (epoch time >> 1496275200) and timeout on midnight November 15th 2017 (epoch time >> 1510704000). 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);
>> }
>>
>> // SEGSIGNAL mandatory segwit signalling.
>> if ( VersionBitsState(pindex->pprev, chainparams.GetConsensus(),
>> Consensus::DEPLOYMENT_SEGSIGNAL, versionbitscache) == THRESHOLD_ACTIVE
>> &&
>>      !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:segsignal-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. Miners will need to upgrade their nodes to >> support segsignal otherwise they may build on top of an invalid block. >> While this bip is active users should either upgrade to segsignal 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. >> >> 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. >> >> ==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-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