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# Rust Bitcoin Library

Library with support for de/serialization, parsing and executing on data
structures and network messages related to Bitcoin and other blockchain-based
currencies.

[Documentation](https://docs.rs/bitcoin/)

Supports (or should support)

* De/serialization of Bitcoin protocol network messages
* De/serialization of blocks and transactions
* Script de/serialization
* Private keys and address creation, de/serialization and validation (including full BIP32 support)
* Pay-to-contract support as in Appendix A of the [Blockstream sidechains whitepaper](https://www.blockstream.com/sidechains.pdf)

For JSONRPC interaction with Bitcoin Core, it is recommended to use [rust-jsonrpc](https://github.com/apoelstra/rust-jsonrpc)
which uses the underlying [strason library](https://github.com/apoelstra/strason)
which parses decimal numbers as strings, preventing precision errors.

# Known limitations

## Consensus

This library **must not** be used for consensus code (i.e. fully validating
blockchain data). It technically supports doing this, but doing so is very
ill-advised because there are many deviations, known and unknown, between
this library and the Bitcoin Core reference implementation. In a consensus
based cryptocurrency such as Bitcoin it is critical that all parties are
using the same rules to validate data, and this library is simply unable
to implement the same rules as Core.

Given the complexity of both C++ and Rust, it is unlikely that this will
ever be fixed, and there are no plans to do so. Of course, patches to
fix specific consensus incompatibilities are welcome.

## Documentation

Currently the [documentation](https://www.wpsoftware.net/rustdoc/bitcoin/)
is very sparse. Patches to add usage examples and to expand on existing
docs would be extremely appreciated.

# Contributing
Contributions are generally welcome. If you intend to make larger changes please discuss them in an issue before PRing 
them to avoid duplicate work and architectural mismatches. If you have any questions or ideas you want to discuss
please join us in [#rust-bitcoin](http://webchat.freenode.net/?channels=%23rust-bitcoin) on freenode.

## Installing Rust
Rust can be installed using your package manager of choice or [rustup.rs](https://rustup.rs). The former way is
considered more secure since it typically doesn't involve trust in the CA system. But you should be aware that the version
of Rust shipped by your distribution might be out of date. Generally this isn't a problem for `rust-bitcoin` since
we support much older versions (>=1.22) than the current stable one.

## Building
The library can be built and tested using [`cargo`](https://github.com/rust-lang/cargo/):

```
git clone git@github.com:rust-bitcoin/rust-bitcoin.git
cd rust-bitcoin
cargo build
```

You can run tests with:

```
cargo test
```

Please refer to the [`cargo` documentation](https://doc.rust-lang.org/stable/cargo/) for more detailed instructions. 

## Pull Requests
Every PR needs at least two reviews to get merged. During the review phase maintainers and contributors are likely to
leave comments and request changes. Please try to address them, otherwise your PR might get closed without merging after
a longer time of inactivity. If your PR isn't ready for review yet please mark it by prefixing the title with `WIP: `.

## Policy on Altcoins/Altchains

Patches which add support for non-Bitcoin cryptocurrencies by adding constants
to existing enums (e.g. to set the network message magic-byte sequence) are
welcome. Anything more involved will be considered on a case-by-case basis,
as the altcoin landscape includes projects which [frequently appear and
disappear, and are poorly designed anyway](https://download.wpsoftware.net/bitcoin/alts.pdf)
and keeping the codebase maintainable is a large priority.

In general, things that improve cross-chain compatibility (e.g. support for
cross-chain atomic swaps) are more likely to be accepted than things which
support only a single blockchain.


# Release Notes

See CHANGELOG.md