litecoin 0.32.8-rc.1

General purpose library for using and interoperating with Litecoin, including MWEB.
Documentation

Supports (or should support)

  • De/serialization of Litecoin protocol network messages (magic bytes 0xFBC0B6DB mainnet, 0xFDD2C8F1 testnet4)
  • De/serialization of blocks and transactions, including MWEB extension blocks and HogEx bridge transactions (segwit flag bits 0x01, 0x08, 0x09)
  • MimbleWimble wire types — kernels, outputs, inputs, peg-in / peg-out coins, compact varints
  • Script de/serialization
  • Litecoin address formats — legacy P2PKH (L… / m…), P2SH (M… / Q… / 2…), segwit v0–v16 bech32/bech32m with ltc / tltc / rltc HRPs, and MWEB stealth addresses (ltcmweb / tmweb)
  • Private keys (WIF prefix 0xB0 mainnet / 0xEF testnet) and BIP32 derivation
  • Litecoin signed-message prefix (\x19Litecoin Signed Message:\n)
  • PSBT v0 de/serialization and all but the Input Finalizer role; PSBT explicitly rejects Transactions carrying MWEB data, since BIP-174 has no field to round-trip it

Known limitations

Consensus

This library must not be used for consensus code (i.e. fully validating blockchain data). It technically supports parsing and re-serializing real Litecoin mainnet blocks (including those containing MWEB extensions and the regression block #2,644,351), but full validation requires matching Litecoin Core bit-for-bit — which this library does not attempt.

In a consensus based cryptocurrency 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. 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

API docs follow upstream rust-bitcoin's structure under the litecoin::* namespace. Most Bitcoin-named types map directly onto Litecoin equivalents; the MWEB-specific surface lives in litecoin::blockdata::mimblewimble and on the Block / Transaction extension fields.

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.

For more information please see ./CONTRIBUTING.md.

Minimum Supported Rust Version (MSRV)

This library should always compile with any combination of features on Rust 1.56.1.

To build with the MSRV you will likely need to pin a bunch of dependencies, see ./contrib/test.sh for the current list.

External dependencies

We integrate with a few external libraries, most notably serde. These are available via feature flags. To ensure compatibility and MSRV stability we provide two lock files as a means of inspecting compatible versions: Cargo-minimal.lock containing minimal versions of dependencies and Cargo-recent.lock containing recent versions of dependencies tested in our CI.

We do not provide any guarantees about the content of these lock files outside of "our CI didn't fail with these versions". Specifically, we do not guarantee that the committed hashes are free from malware. It is your responsibility to review them.

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 since we follow upstream rust-bitcoin's MSRV — much older than the current stable Rust (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-litecoin/rust-litecoin.git
cd rust-litecoin
cargo build

You can run tests with:

cargo test

Please refer to the cargo documentation for more detailed instructions.

Just

We support just for running dev workflow commands. Run just from your shell to see list available sub-commands.

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:

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.

Relationship to upstream rust-bitcoin

This is a fork. We pull from rust-bitcoin/rust-bitcoin periodically and re-apply the Litecoin-specific layer on top — chain identity, MWEB wire types, HogEx handling, LTC address HRPs, magic bytes, genesis, WIF prefix, signed-message prefix. The main crate is published as litecoin; subsidiary crates (bitcoin_hashes, bitcoin-internals, bitcoin-io, bitcoin-units, base58ck) keep their upstream names since they are shared crypto utilities.

Bug reports about the Litecoin layer belong here; bug reports about Bitcoin-shared code should generally be filed upstream first.

Release Notes

Release notes are done per crate, see:

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.