DLC Dev Kit

A ready-to-go Discreet Log Contract node library built using BDK.

DLC Dev Kit is a self-custodial DLC node in library form. Its central goal is to provide a small, simple, and straightforward interface that enables users to easily set up and run a DLC node with an integrated on-chain wallet. While minimalism is at its core, DDK aims to be sufficiently modular and configurable to be useful for a variety of use cases.

Getting Started

The primary abstraction of the library is the DlcDevKit, which can be retrieved by setting up and configuring a Builder to your liking and calling finish(). DlcDevKit can then be controlled via commands such as start, stop, send_dlc_offer, accept_dlc_offer, etc.

use ddk::builder::{Builder, SeedConfig};
use ddk::logger::{LogLevel, Logger};
use ddk::oracle::kormir::KormirOracleClient;
use ddk::storage::sled::SledStorage;
use ddk::transport::lightning::LightningTransport;
use std::sync::Arc;

type ApplicationDdk = ddk::DlcDevKit<LightningTransport, SledStorage, KormirOracleClient>;

#[tokio::main]
async fn main() -> Result<(), ddk::error::Error> {
    let logger = Arc::new(Logger::console("ddk-example".to_string(), LogLevel::Info));

    let transport = Arc::new(LightningTransport::new(&[0u8; 32], 1776, logger.clone())?);
    let storage = Arc::new(SledStorage::new("/tmp/ddk-example", logger.clone())?);
    let oracle = Arc::new(KormirOracleClient::new("http://localhost:8082", None, logger.clone()).await?);

    let mut builder: Builder<LightningTransport, SledStorage, KormirOracleClient> = Builder::new();
    builder.set_seed_bytes(SeedConfig::Random)?;
    builder.set_esplora_host("https://mutinynet.com/api".to_string());
    builder.set_transport(transport);
    builder.set_storage(storage);
    builder.set_oracle(oracle);
    builder.set_logger(logger);

    let ddk: ApplicationDdk = builder.finish().await?;

    ddk.start()?;

    // ... open contracts, accept offers, etc.

    ddk.stop()?;
    Ok(())
}

Modularity

DDK is designed with a pluggable architecture, allowing you to choose or implement your own components:

• Transport: Communication layer for DLC messages between peers. Implementations include Lightning Network gossip and Nostr protocol messaging.
• Storage: Persistence backend for contracts and wallet data. Implementations include Sled (embedded) and PostgreSQL.
• Oracle: External data source for contract attestations. Implementations include HTTP and Nostr-based oracle clients.

You can create a custom DDK instance by implementing the required traits defined in ddk/src/lib.rs.

Crates

Crate	Description
ddk	The main DDK library with an integrated BDK wallet for building DLC applications.
ddk-node	A ready-to-go DLC node with a gRPC server and accompanying CLI.
ddk-payouts	Functions to build payout curves for DLC contracts.
ddk-manager	Core DLC contract creation and state machine management.
ddk-dlc	Low-level DLC transaction creation, signing, and verification.
ddk-messages	Serialization and structs for the DLC protocol messages.
ddk-trie	Data structures for storage and retrieval of numerical DLCs.
kormir	Oracle implementation for creating and attesting to DLC events.

Development

A bitcoin node, esplora server, and oracle server are required to run DDK. Developers can spin up a development environment with the justfile provided.

$ just deps

To run your own Kormir oracle server for development, see the Kormir repository.

See the ddk-node README for more development information.

Language Bindings

For Node.js and React Native bindings, see ddk-ffi.

Resources

• DLC Dev Kit Blog - Guides and API walkthroughs
• DLC Dev Kit: Beyond - Deep dive into the project
• What is a Discreet Log Contract? - Learn about DLCs
• DLC Specifications - Protocol specification
• rust-dlc - The original rust-dlc implementation

License

This project is licensed under the MIT License.