[![Status](https://travis-ci.org/apoelstra/rust-bitcoin.png?branch=master)](https://travis-ci.org/apoelstra/rust-bitcoin)

# 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://www.wpsoftware.net/rustdoc/bitcoin/)

Supports (or should support)

* De/serialization of Bitcoin protocol network messages
* De/serialization of blocks and transactions
* Script de/serialization and execution
* Blockchain validation and utxoset building
* 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)

# Usage

To use rust-bitcoin, just add the following to your Cargo.toml.

```toml
[dependencies]
bitcoin = "0.3"
```

# 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.

## Memory Usage

Currently this library's UTXO-set support is limited to an in-RAM hash tree.
It can be serialized and deserialized to disk to avoid recomputing it all
the time, but needs to be in memory to be used, which currently requires
several gigabytes of RAM.

Patches are welcome. This is a priority but not a high one, due to lack of
developer time.

## 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.


# 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.