Superchain ERC20 Token

A cross-chain compatible ERC20 token implementation designed for the Optimism ecosystem. This token can be bridged across different chains in the Optimism Superchain using the L2 Standard Bridge.

Features

• ERC20 token with cross-chain capabilities
• Compatible with Optimism's L2 Standard Bridge
• Built with Solady for gas optimization
• Supports ERC165 interface detection
• Implements ISemver for version tracking
• Fully audited and tested codebase

Contract Architecture

Core Contracts

1. BTBFinance.sol

   • Main token contract that inherits from SuperchainERC20
   • Implements token-specific logic (name, symbol, decimals)
   • Manages token supply and ownership
   • Uses Solady's Ownable for efficient ownership management

2. SuperchainERC20.sol

   • Abstract base contract for cross-chain functionality
   • Implements IERC7802 for cross-chain token standards
   • Handles bridge minting and burning through L2 Standard Bridge
   • Version tracking through ISemver
   • Current version: 1.0.0-beta.8

Interfaces

1. IERC7802.sol

   • Standard interface for cross-chain token operations
   • Defines crosschainMint and crosschainBurn functions
   • Includes event definitions for cross-chain operations

2. ISemver.sol

   • Interface for semantic versioning
   • Enables version tracking across contract upgrades

Libraries

1. Predeploys.sol (from @eth-optimism/contracts-bedrock)

   • Contains L2 predeploy addresses
   • Used for L2 Standard Bridge integration

2. CommonErrors.sol

   • Common error definitions
   • Includes Unauthorized() error

Technical Details

Dependencies

{
  "@eth-optimism/contracts-bedrock": "latest",
  "@openzeppelin/contracts": "^5.0.1",
  "@rari-capital/solmate": "^6.4.0",
  "solady": "^0.0.294",
  "ethers": "^6.9.0"
}

Solidity Version

• Solidity 0.8.25 with optimizer enabled
• Uses IR-based code generation (viaIR: true)

Important Contract Addresses

The contract uses several predefined addresses from the Optimism ecosystem:

• L2 Standard Bridge: 0x4200000000000000000000000000000000000010
• L2 Cross Domain Messenger: 0x4200000000000000000000000000000000000007

Cross-Chain Functionality

The token implements cross-chain capabilities through:

1. CrosschainMint Function

   function crosschainMint(address _to, uint256 _amount) external

   • Restricted to L2 Standard Bridge
   • Used for receiving tokens from other chains

2. CrosschainBurn Function

   function crosschainBurn(address _from, uint256 _amount) external

   • Restricted to L2 Standard Bridge
   • Used when sending tokens to other chains

Development Setup

1. Clone the Repository

   git clone <repository-url>
   cd SuperChainToken

2. Install Dependencies

   npm install

3. Environment Setup Create a .env file with:

   PRIVATE_KEY=your_private_key
   OP_SEPOLIA_RPC_URL=https://sepolia.optimism.io
   ETHERSCAN_API_KEY=your_etherscan_api_key

4. Compile Contracts

   npx hardhat compile

5. Run Tests

   npx hardhat test

6. Deploy

   npx hardhat run scripts/deploy.ts --network op-sepolia

Security Considerations

1. Access Control

   • Bridge operations restricted to L2 Standard Bridge
   • Owner functions protected by Solady's Ownable
   • No direct mint/burn functions exposed

2. Audited Codebase

   • All contracts have been audited
   • No modifications to core contract logic
   • Using well-tested dependencies

3. Error Handling

   • Custom error definitions for gas efficiency
   • Clear error messages for debugging

File Structure

SuperChainToken/
├── contracts/
│   ├── BTBFinance.sol
│   ├── interfaces/
│   │   ├── L2/
│   │   │   ├── IERC7802.sol
│   │   │   └── SuperchainERC20.sol
│   │   └── universal/
│   │       └── ISemver.sol
│   └── libraries/
│       └── errors/
│           └── CommonErrors.sol
├── scripts/
│   └── deploy.ts
├── test/
├── .env
├── .gitignore
├── hardhat.config.ts
└── package.json

License

MIT