@offchainlabs/stablecoin-evm v1.0.0-orbit-alpha.0
Circle's Stablecoin Smart Contracts on EVM-compatible blockchains
This repository contains the smart contracts used by Circle's stablecoins on EVM-compatible blockchains. All contracts are written in Solidity and managed by the Hardhat framework.
Table of contents
Setup
Development Environment
Requirements:
- Node 16.14.0
- Yarn 1.22.19
- Foundry@f625d0f
$ git clone git@github.com:circlefin/stablecoin-evm.git
$ cd stablecoin-evm
$ nvm use
$ npm i -g yarn@1.22.19 # Install yarn if you don't already have it
$ yarn install # Install npm packages and other dependencies listed in setup.shIDE
We recommend using VSCode for the project here with these extensions installed.
Development
TypeScript type definition files for the contracts
Types are automatically generated as a part of contract compilation:
$ yarn compileTo generate typing without re-compiling, run
$ yarn hardhat typechainLinting and Formatting
To check code for problems:
$ yarn static-check # Runs a static check on the repo.or run the checks individually:
$ yarn typecheck # Type-check TypeScript code
$ yarn lint # Check JavaScript and TypeScript code
$ yarn lint --fix # Fix problems where possible
$ yarn solhint # Check Solidity codeTo auto-format code:
$ yarn fmtTesting
Run all tests:
$ yarn testTo run tests in a specific file, run:
$ yarn test [path/to/file]To run tests and generate test coverage, run:
$ yarn coverageTo check the size of contracts in the repo, run the following command.
$ yarn contract-size # Ignores testsDeployment
- Create a copy of the file
.env.example, and name it.env. Fill in appropriate values in the.envfile. This file must not be checked into the repository.
cp .env.example .env- Create a
blacklist.remote.jsonfile and populate it with a list of addresses to be blacklisted. This file must not be checked into the repository.
echo "[]" > blacklist.remote.json- Simulate a deployment by running the following command
yarn forge:simulate scripts/deploy/deploy-fiat-token.s.sol --rpc-url <testnet OR mainnet>- Validate that all transactions to be broadcasted are filled in with the correct values
- Deploy the contracts by running the following command
yarn forge:broadcast scripts/deploy/deploy-fiat-token.s.sol --rpc-url <testnet OR mainnet>- Verify the contracts on an Etherscan flavored block explorer by running the
following command. Ensure that
ETHERSCAN_KEYis set in the.envfile.
yarn forge:verify scripts/deploy/deploy-fiat-token.s.sol --rpc-url <testnet OR mainnet>Contracts
The FiatToken contracts adheres to OpenZeppelin's
Proxy Upgrade Pattern
(permalink).
There are 2 main contracts - an implementation contract
(FiatTokenV2_2.sol) that contains the main
logic for FiatToken's functionalities, and a proxy contract
(FiatTokenProxy.sol) that redirects
function calls to the implementation contract. This allows upgrading FiatToken's
functionalities, as a new implementation contact can be deployed and the Proxy
can be updated to point to it.
FiatToken features
The FiatToken offers a number of capabilities, which briefly are described
below. There are more detailed design docs in the doc
directory.
ERC20 compatible
The FiatToken implements the ERC20 interface.
Pausable
The entire contract can be frozen, in case a serious bug is found or there is a
serious key compromise. No transfers can take place while the contract is
paused. Access to the pause functionality is controlled by the pauser address.
Upgradable
A new implementation contract can be deployed, and the proxy contract will
forward calls to the new contract. Access to the upgrade functionality is
guarded by a proxyOwner address. Only the proxyOwner address can change the
proxyOwner address.
Blacklist
The contract can blacklist certain addresses which will prevent those addresses
from transferring or receiving tokens. Access to the blacklist functionality is
controlled by the blacklister address.
Minting/Burning
Tokens can be minted or burned on demand. The contract supports having multiple
minters simultaneously. There is a masterMinter address which controls the
list of minters and how much each is allowed to mint. The mint allowance is
similar to the ERC20 allowance - as each minter mints new tokens their allowance
decreases. When it gets too low they will need the allowance increased again by
the masterMinter.
Ownable
The contract has an Owner, who can change the owner, pauser, blacklister,
or masterMinter addresses. The owner can not change the proxyOwner
address.