Rust Bitcoin

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

Documentation

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)
• PSBT v0 de/serialization and all but the Input Finalizer role. Use rust-miniscript to finalize.

For JSONRPC interaction with Bitcoin Core, it is recommended to use rust-bitcoincore-rpc.

It is recommended to always use cargo-crev to verify the trustworthiness of each of your dependencies, including this one.

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.

Support for 16-bit pointer sizes

16-bit pointer sizes are not supported and we can't promise they will be. If you care about them please let us know, so we can know how large the interest is and possibly decide to support them.

Documentation

Currently can be found on docs.rs/bitcoin. 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 #bitcoin-rust on libera.chat.

For more information please see ./CONTRIBUTING.md.

Minimum Supported Rust Version (MSRV)

This library should always compile with any combination of features on Rust 1.48.0.

To build with the MSRV you will need to pin serde (if you have the feature enabled)

# serde 1.0.157 uses syn 2.0 which requires edition 2021
cargo update -p serde --precise 1.0.156

before building. (And if your code is a library, your downstream users will need to run these commands, and so on.)

Installing Rust

Rust can be installed using your package manager of choice or 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 than the current stable one (see MSRV section).

Building

The cargo feature std is enabled by default. At least one of the features std or no-std or both must be enabled.

Enabling the no-std feature does not disable std. To disable the std feature you must disable default features. The no-std feature only enables additional features required for this crate to be usable without std. Both can be enabled without conflict.

The library can be built and tested using 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 for more detailed instructions.

Building the docs

We build docs with the nightly toolchain, you may wish to use the following shell alias to check your documentation changes build correctly.

alias build-docs='RUSTDOCFLAGS="--cfg docsrs" cargo +nightly rustdoc --features="$FEATURES" -- -D rustdoc::broken-intra-doc-links'

Testing

Unit and integration tests are available for those interested, along with benchmarks. For project developers, especially new contributors looking for something to work on, we do:

• Fuzz testing with Hongfuzz
• Mutation testing with Mutagen
• Code verification with Kani

There are always more tests to write and more bugs to find, contributions to our testing efforts extremely welcomed. Please consider testing code a first class citizen, we definitely do take PRs improving and cleaning up test code.

Unit/Integration tests

Run as for any other Rust project cargo test --all-features.

Benchmarks

We use a custom Rust compiler configuration conditional to guard the bench mark code. To run the bench marks use: RUSTFLAGS='--cfg=bench' cargo +nightly bench.

Mutation tests

We have started doing mutation testing with mutagen. To run these tests first install the latest dev version with cargo +nightly install --git https://github.com/llogiq/mutagen then run with RUSTFLAGS='--cfg=mutate' cargo +nightly mutagen.

Code verification

We have started using kani, install with cargo install --locked kani-verifier (no need to run cargo kani setup). Run the tests with cargo kani.

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: .

CI Pipeline

The CI pipeline requires approval before being run on each MR.

In order to speed up the review process the CI pipeline can be run locally using act. The fuzz and Cross jobs will be skipped when using act due to caching being unsupported at this time. We do not actively support act but will merge PRs fixing act issues.

Githooks

To assist devs in catching errors before running CI we provide some githooks. If you do not already have locally configured githooks you can use the ones in this repository by running, in the root directory of the repository:

git config --local core.hooksPath githooks/

Alternatively add symlinks in your .git/hooks directory to any of the githooks we provide.

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 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

Release notes are done per crate, see:

• bitcoin CHANGELOG
• hashes CHANGELOG
• internals CHANGELOG

Licensing

The code in this project is licensed under the Creative Commons CC0 1.0 Universal license. We use the SPDX license list and SPDX IDs.