3942a116e4
First, it removes the documentation section from all the README.md files and instead puts a web-based godoc badge and link at the top with the other badges. This is being done since the local godoc tool no longer ships with Go by default, so the instructions no longer work without first installing godoc. Due to this, pretty much everyone uses the web-based godoc these days anyways. Anyone who has manually installed godoc won't need instructions. Second, it makes sure the ISC license badge is at the top with the other badges and removes the textual reference in the overview section. Finally, it's modifies the Installation section to Installation and Updating and adds a '-u' to the 'go get' command since it works for both and thus is simpler.
108 lines
4.7 KiB
Markdown
108 lines
4.7 KiB
Markdown
blockchain
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==========
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[]
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(https://travis-ci.org/btcsuite/btcd) [![ISC License]
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(http://img.shields.io/badge/license-ISC-blue.svg)](http://copyfree.org)
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[]
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(http://godoc.org/github.com/btcsuite/btcd/blockchain)
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Package blockchain implements bitcoin block handling and chain selection rules.
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The test coverage is currently only around 60%, but will be increasing over
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time. See `test_coverage.txt` for the gocov coverage report. Alternatively, if
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you are running a POSIX OS, you can run the `cov_report.sh` script for a
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real-time report. Package blockchain is licensed under the liberal ISC license.
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There is an associated blog post about the release of this package
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[here](https://blog.conformal.com/btcchain-the-bitcoin-chain-package-from-bctd/).
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This package has intentionally been designed so it can be used as a standalone
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package for any projects needing to handle processing of blocks into the bitcoin
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block chain.
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## Installation and Updating
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```bash
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$ go get -u github.com/btcsuite/btcd/blockchain
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```
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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
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## Examples
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* [ProcessBlock Example]
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(http://godoc.org/github.com/btcsuite/btcd/blockchain#example-BlockChain-ProcessBlock)
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Demonstrates how to create a new chain instance and use ProcessBlock to
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attempt to attempt add a block to the chain. This example intentionally
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attempts to insert a duplicate genesis block to illustrate how an invalid
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block is handled.
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* [CompactToBig Example]
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(http://godoc.org/github.com/btcsuite/btcd/blockchain#example-CompactToBig)
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Demonstrates how to convert the compact "bits" in a block header which
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represent the target difficulty to a big integer and display it using the
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typical hex notation.
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* [BigToCompact Example]
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(http://godoc.org/github.com/btcsuite/btcd/blockchain#example-BigToCompact)
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Demonstrates how to convert how to convert a target difficulty into the
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compact "bits" in a block header which represent that target difficulty.
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## GPG Verification Key
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All official release tags are signed by Conformal so users can ensure the code
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has not been tampered with and is coming from the btcsuite developers. To
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verify the signature perform the following:
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- Download the public key from the Conformal website at
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https://opensource.conformal.com/GIT-GPG-KEY-conformal.txt
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- Import the public key into your GPG keyring:
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```bash
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gpg --import GIT-GPG-KEY-conformal.txt
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```
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- Verify the release tag with the following command where `TAG_NAME` is a
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placeholder for the specific tag:
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```bash
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git tag -v TAG_NAME
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```
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## License
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Package blockchain is licensed under the [copyfree](http://copyfree.org) ISC
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License.
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