39 lines
2.1 KiB
Markdown
39 lines
2.1 KiB
Markdown
blockchain
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==========
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[](http://copyfree.org)
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### Bitcoin Chain Processing Overview
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Before a block is allowed into the block chain, it must go through an intensive
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series of validation rules. The following list serves as a general outline of
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those rules to provide some intuition into what is going on under the hood, but
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is by no means exhaustive:
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- Reject duplicate blocks
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- Perform a series of sanity checks on the block and its transactions such as
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verifying proof of work, timestamps, number and character of transactions,
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transaction amounts, script complexity, and merkle root calculations
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- Compare the block against predetermined checkpoints for expected timestamps
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and difficulty based on elapsed time since the checkpoint
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- Save the most recent orphan blocks for a limited time in case their parent
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blocks become available
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- Stop processing if the block is an orphan as the rest of the processing
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depends on the block's position within the block chain
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- Perform a series of more thorough checks that depend on the block's position
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within the block chain such as verifying block difficulties adhere to
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difficulty retarget rules, timestamps are after the median of the last
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several blocks, all transactions are finalized, checkpoint blocks match, and
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block versions are in line with the previous blocks
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- Determine how the block fits into the chain and perform different actions
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accordingly in order to ensure any side chains which have higher difficulty
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than the main chain become the new main chain
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- When a block is being connected to the main chain (either through
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reorganization of a side chain to the main chain or just extending the
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main chain), perform further checks on the block's transactions such as
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verifying transaction duplicates, script complexity for the combination of
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connected scripts, coinbase maturity, double spends, and connected
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transaction values
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- Run the transaction scripts to verify the spender is allowed to spend the
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coins
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- Insert the block into the block database |