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# Farcaster Core Library

The Farcaster atomic swaps project core library aim to implement in Rust the following functionalities needed to build a swap node:

- [x] Swap deals (contains all necessary information to start a swap)
- [x] Swap roles and trade roles (who does what during the swap)
- [x] Transaction templates implementing on-chain behaviours (arbitration engine, e.g. on Bitcoin blockchain)
- [x] Signature and cryptographic utilities
  - [x] ECDSA adaptor signatures
  - [x] Cross-group discrete logarithm proof system
  - [ ] Schnorr adaptor signature
- [x] Messages exchanged between [farcaster nodes](https://github.com/farcaster-project/farcaster-node), i.e. the peer-to-peer messages also called _protocol messages_.

## Documentation

Check out the documentation of this library on [docs.rs/farcaster_core](https://docs.rs/farcaster_core). All possible improvements, such as adding usage examples and expanding on existing docs would be extremely appreciated.

## Core framework

This library's purpose is twofold: providing a flexible framework to add specific blockchain support and implementing these specific blockchains (currently _bitcoin_ and _monero_). The framework is split in modules at the root of the crate:

- `blockchain`: generic types and traits for declaring assets/chains and on-chain behavior.
- `consensus`: encoding and decoding implementation for all types in the crate, used to serialize and deserialize messages exchanged.
- `crypto`: traits and generic types to define cryptographic interactions (wallet capability, commit/reveal scheme, signature and key types, etc).
- `trade`: generic types and utilities for handling the trade setup, e.g. creating a deal.
- `protocol`: generic types related to the execution of the protocol and messages exchanged between peers.
- `role`: role definitions (trade and swap) and trait for the generic framework.
- `script`: generic types for transaction data management.
- `swap`: swap related types and swap concrete instances (e.g. _bitcoin-monero_).
- `transaction`: transaction traits for building and validating the arbitrating set of transactions, i.e. the on-chain engine that implements the protocol's game-theoretic mechanism.

The blockchain specific support is added under the the following modules:

- `bitcoin`: support for Bitcoin, implementation of all required traits from the framework, e.g. the `Arbitrating` blockchain role.
- `monero`: support for Monero, implementation of all required traits from the framework, e.g. the `Accordant` blockchain role.
- `swap/btcxmr`: definition of a swap between `bitcoin` and `monero` modules with re-export of the majority of generic types with fixed types associated to `bitcoin` and `monero`.

### Features

The `experimental` a,d `taproot` features are enabled by default.

- **experimental**: enables experimental cryptography, i.e. not battle tested nor peer reviewed, use it at your own risks.
- **taproot**: [work in progress] enables support for Bitcoin Taproot on-chain scripts as the arbitrating engine method.

### Adding blockchain support

Check `bitcoin`, `monero`, and `swap/btcxmr` modules to see and example of swap pair. For more details on high level context see the [RFCs](https://github.com/farcaster-project/RFCs).

## Releases and Changelog

See [CHANGELOG.md](CHANGELOG.md) and [RELEASING.md](RELEASING.md).

## About

This work is part of the Farcaster cross-chain atomic swap project, see [Farcaster Project](https://github.com/farcaster-project).

## Licensing

The code in this project is licensed under the [LGPL-3.0 License](LICENSE)