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70 lines
2.7 KiB
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70 lines
2.7 KiB
Plaintext
<pre>
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BIP: 149
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Layer: Consensus (soft fork)
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Title: Segregated Witness (second deployment)
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Author: Shaolin Fry <shaolinfry@protonmail.ch>
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Comments-Summary: No comments yet.
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Comments-URI: https://github.com/bitcoin/bips/wiki/Comments:BIP-0149
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Status: Withdrawn
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Type: Standards Track
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Created: 2017-04-14
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License: BSD-3-Clause
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CC0-1.0
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</pre>
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==Abstract==
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This document specifies a user activated soft fork for [[bip-0141.mediawiki|BIP141]], [[bip-0143.mediawiki|BIP143]] and [[bip-0147.mediawiki|BIP147]] using versionbits with guaranteed lock-in.
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==Motivation==
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Miners have been reluctant to signal the BIP9 segwit deployment despite a large portion of the Bitcoin ecosystem who want the soft fork activated. This BIP specifies a user activated soft fork (UASF) that deploys segwit again using versionbits with guaranteed lock-in on timeout if the BIP is not already locked-in or activated by the timeout. This ensures users have sufficient time to prepare and no longer require a miner supermajority, while still allowing for an earlier miner activated soft fork (MASF).
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==Reference implementation==
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The reference implementation will refuse to run on Bitcoin mainnet before 7 November 2017, and can only be run on testnet and regtest until then.
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https://github.com/bitcoin/bitcoin/compare/master...shaolinfry:uasegwit-flagday
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==Specification==
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This deployment will set service bit (1<<5) as NODE_UAWITNESS.
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==Deployment==
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This BIP should only be deployed if BIP9-segwit fails to lock-in or activate before timeout on 15 November 2017. This BIP cannot be deployed before 15 November 2017.
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This BIP will be deployed by BIP8 with the name "segwit" and using bit 1.
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For Bitcoin mainnet, the BIP8 starttime will be midnight 16 November 2017 UTC (Epoch timestamp 1510790400) and BIP8 timeout will be 4 July 2018 UTC (Epoch timestamp 1530662400).
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For Bitcoin testnet, segwit is already activated so no deployment is specified.
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==Backwards Compatibility==
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This deployment reuses the GBT deployment name "segwit" to maintain compatibility with existing mining software.
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This deployment is incompatible with the BIP9-segwit deployment and should not be run concurrently with it.
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==Rationale==
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The '''starttime''' of this BIP is after the BIP9-segwit timeout to remove compatibility issues with old nodes.
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==References==
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[https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2017-April/014234.html Mailing list discussion]
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[[bip-0008.mediawiki|BIP8]]
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[[bip-0009.mediawiki|BIP9]]
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[[bip-0141.mediawiki|BIP141]]
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[[bip-0143.mediawiki|BIP143]]
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[[bip-0147.mediawiki|BIP147]]
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==Copyright==
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This document is dual licensed as BSD 3-clause, and Creative Commons CC0 1.0 Universal.
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