centre-tokens

Fiat tokens on the CENTRE network.

Setup

Requirements:

• Node >= v12
• Yarn

$ git clone git@github.com:centrehq/centre-tokens.git
$ cd centre-tokens
$ npm i -g yarn       # Install yarn if you don't already have it
$ yarn install        # Install dependencies
$ yarn setup          # Setup Git hooks

TypeScript type definition files for the contracts

To generate type definitions:

$ yarn compile && yarn typechain

Linting and Formatting

To check code for problems:

$ yarn typecheck      # Type-check TypeScript code
$ yarn lint           # Check JavaScript and TypeScript code
$ yarn lint --fix     # Fix problems where possible
$ yarn solhint        # Check Solidity code
$ yarn slither        # Run Slither

To auto-format code:

$ yarn fmt

Testing

First, make sure Ganache is running.

$ yarn ganache

Run all tests:

$ yarn test

To run tests in a specific file, run:

$ yarn test [path/to/file]

To run tests and generate test coverage, run:

$ yarn coverage

Deployment

Create a copy of the file config.js.example, and name it config.js. Enter the BIP39 mnemonic phrase, the INFURA API key to use for deployment, and the addresses of proxy admin, owner, master minter, blacklister, and pauser in config.js. This file must not be checked into the repository. To prevent accidental check-ins, config.js is in .gitignore.

Run yarn migrate --network NETWORK, where NETWORK is either mainnet or ropsten.

Contracts

The implementation uses 2 separate contracts - a proxy contract (FiatTokenProxy.sol) and an implementation contract (FiatToken.sol). This allows upgrading the contract, as a new implementation contact can be deployed and the Proxy updated to point to it.

FiatToken

The FiatToken offers a number of capabilities, which briefly are described below. There are more detailed design docs in the doc folder.

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.