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			37 lines
		
	
	
		
			2.0 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
	
	
<pre>
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  BIP: 34
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  Title: Block v2, Height in Coinbase
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  Author: Gavin Andresen <gavinandresen@gmail.com>
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  Status: Accepted
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  Type: Standards Track
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  Created: 2012-07-06
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</pre>
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==Abstract==
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Bitcoin blocks and transactions are versioned binary structures. Both currently use version 1. This BIP introduces an upgrade path for versioned transactions and blocks. A unique value is added to newly produced coinbase transactions, and blocks are updated to version 2.
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==Motivation==
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# Clarify and exercise the mechanism whereby the bitcoin network collectively consents to upgrade transaction or block binary structures, rules and behaviors.
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# Enforce block and transaction uniqueness, and assist unconnected block validation.
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==Specification==
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# Treat transactions with a version greater than 1 as non-standard (official Satoshi client will not mine or relay them).
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# Add height as the first item in the coinbase transaction's scriptSig, and increase block version to 2. The format of the height is "serialized CScript" -- first byte is number of bytes in the number (will be 0x03 on main net for the next 300 or so years), following bytes are little-endian representation of the number.  Height is the height of the mined block in the block chain, where the genesis block is height zero (0).
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# 75% rule: If 750 of the last 1,000 blocks are version 2 or greater, reject invalid version 2 blocks. (testnet3: 51 of last 100)
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# 95% rule ("Point of no return"): If 950 of the last 1,000 blocks are version 2 or greater, reject all version 1 blocks. (testnet3: 75 of last 100)
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==Backward compatibility==
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All older clients are compatible with this change. Users and merchants should not be impacted. Miners are strongly recommended to upgrade to version 2 blocks. Once 95% of the miners have upgraded to version 2, the remainder will be orphaned if they fail to upgrade.
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==Implementation==
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https://github.com/bitcoin/bitcoin/pull/1526
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==Result==
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Block number 227,835 (timestamp 2013-03-24 15:49:13 GMT) was the last version 1 block.
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