This repo contains the solidity smart contracts for the DLC.Link infrastructure and the dlcBTC token.
Learn more about DLCs and dlcBTC.
A DLC is a contract on Bitcoin that enables users to move/lock Bitcoin conditionally. The possible outcomes of a DLC are predefined and stored by the DLC.Link Attestor Layer. Bitcoin locked in such a way can be represented then on any EVM chain using these smart contracts. The outcome - that is, the value that will be 'attested' to - is supplied by smart contracts too.
This way, any EVM chain can essentially move native Bitcoin in a safe, "bridgeless" way. Ethereum can leverage the power of DLCs and the trust-minimised Attestor Layer that DLC.Link provides.
dlcBTC is a token that represents Bitcoin locked in DLCs. It is minted when Bitcoin is locked in a DLC and burned when the DLC is settled.
Learn more about the whole architecture on the documentation site here: https://docs.dlc.link/architecture/tech-stack
Some of the contracts in this repository are upgradeable. They can be changed by a multisig of dlcBTC team and external members. The upgrade process is timelocked, meaning that the upgrade will only happen after a certain time has passed (minimum 7 days). This is to ensure that the community has time to review the changes and react if necessary.
npm run test
*optionally, REPORT_GAS=true npm run test to see gas usage.
Modify the hardhat.config.js for more testing / deployment options.
npm run coverage
In the root folder, run:
npm run analyze
In the scripts directory you will find various helper scripts.
Create a .env based on the .env.template fields.
Be sure to set the correct HARDHAT_NETWORK for the scripts to work properly. (Set 'localhost' when using hardhat).
The easiest way to use them is by running the package:
# If the following throws a 'command not found: dlc-link-eth' error, try running 'npm link' after 'npm i' to set up the symlink for your $PATH
# To see help:
dlc-link-eth --help
# For example for contract deployment and admin scripts:
dlc-link-eth contract-adminTo start a local hardhat node to test against:
npx hardhat nodeNote that properly testing the entire DLC creation flow requires more of the DLC.Link infrastructure running -- but contract-integration can still be tested thoroughly and easily using the testing framework.
We are happy to have support and contribution from the community. Please find us on Discord and see below for developer details.
For reference, you can find samples of the deployed contract by checking the deploymentFiles directory in this project.
Add a .env file with the following fields:
# Infura key
INFURA_PROJECT_ID=
# Deployer private key
KEY=
# optional
KEY2=
# optional
KEY3=
# Etherscan API KEY (optional)
# only needed for submitting the contract to etherscan
ETHERSCAN_API_KEY=
# Network to use e.g. localhost(for hardhat)/goerli/sepolia/mainnet
HARDHAT_NETWORK=
# Coinmarketcap API KEY (optional, for gas calculations)
COINMARKETCAP_API_KEY=
# Report gas usage after test run (optional) boolean
REPORT_GAS=
# SAFE key signer (optional)
SCRIPT_KEY=
Discreet Log Contracts (DLCs) facilitate conditional payments on Bitcoin between two or more parties. By creating a Discreet Log Contract, two parties can form a monetary contract redistributing their funds to each other without revealing any details to the blockchain. Its appearance on the Bitcoin blockchain will be no different than an ordinary multi-signature output, so no external observer can learn its existence or details from the public ledger. A DLC is similar to a 2-of-3 multisig transaction where the third participant is an “oracle”. An oracle is a 3rd party source of data or information that the parties to the DLC trust as the source of truth for the contract. The oracle is incentivized to be a fair arbiter of the contract.
DLC.Link is building infrastructure to empower decentralized applications and smart contract developers to easily leverage the power of DLCs. We provide companies and applications with a traditional REST API and a smart contract interface to create and manage DLCs for their use cases.
DLCs require an oracle to attest to a specific outcome among the predefined set of outcomes. That means trust.
Why power DLC oracles with smart contracts? By using a smart contract for this task, the implementation of the logic, as well as the data being used, is stamped on the chain, and is visible and reviewable by everyone.
Unlike other DLC Oracle server solutions, DLC.link allows the DLCs to be configured with a simple interface, API or via smart contract, and to act on a wide-set of events and data sources through our decentralized infrastructure.
There are two types of events / data sources supported by DLC.link.
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Off-chain pricing data, such as the current price of BTC, ETH, etc. In fact, any numeric data from Chainlink Oracle Network is supported.
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On-chain events, such as a completed transaction, a function call, etc.