Fuse V2 Bridge

Wrapped asset bridge allows bridging ERC20 tokens and native gas tokens (e.g. ETH) from existing EVM chains (e.g. Ethereum, Avalanche, BSC, etc.) to subnets or brand new EVM chains where those assets do not exist natively. It supports mapping the same wrapped token to multiple tokens on other chains. E.g. moving native USDC from Ethereum or Avalanche to NewChainX will result in the same wrapped asset on NewChainX.

Getting Started

Setup

Clone the repository
run yarn

Test

yarn test

Run the full suite of unit tests.

Coverage

yarn coverage

Get the coverage report.

Deployment and configuration

Deploy OriginalTokenBridge.sol on existing EVM chains.
Deploy WrappedTokenBridge.sol on the new EVM chain.
Call setTrustedRemoteAddress in WrappedTokenBridge contract and in each OriginalTokenBridge contract.
For each token you want to bridge (e.g., USDC, WETH, etc), deploy WrappedERC20 contract on the new EVM chain. Make sure to set decimals in the WrappedERC20 to the number of decimals used in the original token you want to bridge (e.g., 6 decimals for USDC, 18 decimals for WETH). If you want to add an additional functionality to the wrapped token, inherit it from WrappedERC20 and add a custom logic to the derived contract.
For each token you want to bridge, call registerToken(address token, uint8 sharedDecimals) function in OriginalTokenBridge and registerToken(address localToken, uint16 remoteChainId, address remoteToken) function in WrappedTokenBridge. Each wrapped token can be mapped to multiple original tokens on different chains (e.g. USDC on the new chain is mapped to USDC on Ethereum and USDC on Avalanche).

Bridging from a native asset EVM chain to a new EVM chain

Call estimateBridgeFee(bool useZro, bytes calldata adapterParams) in OriginalTokenBridge contract.
Call bridge(address token, uint amountLD, address to, LzLib.CallParams calldata callParams, bytes memory adapterParams) in OriginalTokenBridge contract to bridge ERC20 tokens passing nativeFee obtained earlier as a value. This will lock ERC20 tokens in OriginalTokenBridge contract and send a LayerZero message to the WrappedTokenBridge on another chain to mint wrapped tokens. To bridge ETH use bridgeNative(uint amountLD, address to, LzLib.CallParams calldata callParams, bytes memory adapterParams) function and pass a sum of nativeFee and amount as a value.

Bridging from a new EVM chain to a native asset EVM

Call estimateBridgeFee(uint16 remoteChainId, bool useZro, bytes calldata adapterParams) in WrappedTokenBridge.
Call bridge(address localToken, uint16 remoteChainId, uint amount, address to, bool unwrapWeth, LzLib.CallParams calldata callParams, bytes memory adapterParams) supplying nativeFee obtained earlier as a value. This will burn wrapped tokens and send a LayerZero message to OriginalTokenBridge contract on another chain to unlock original tokens.

Using Scripts

To deploy fresh contracts plese delete the contents of the deployments folder.

Populate the env MNENOIC in the env file and run the following commands in order.

npx hardhat deployBridges --original-networks "polygon,gnosis" --wrapped-network "fuse"

Now populate the Bridge address on Fuse in the env file and proceed.

npx hardhat deployTestTokens --original-networks "fuse"
npx hardhat setTrustedRemote --original-networks "gnosis" --wrapped-network "fuse"
npx hardhat registerTokens --original-networks "gnosis" --wrapped-network "fuse" --tokens "USDC,USDT,WETH"

New tokens can be added by adding them in constants and updating the list in deploy/WrappedERC20.js

Deployed Proxy Contracts

Polygon

OriginalTokenBridge: 0x8f5D6332eD11338D2dA4fAAC6675e9A6757BeC8b
WrappedTokenBridge: 0xe453d6649643F1F460C371dC3D1da98F7922fe51

Gnosis

OriginalTokenBridge: 0xb0F9cE8598c623Ff42e52388F9b452B7CDc409a1
WrappedTokenBridge: 0x4014115fB4816Bc8343d8e69d2708Fa738dCaa15

Optimism

OriginalTokenBridge: 0x081dF5af5d022D4A4a4520D4D0D336B8432fDBBb
WrappedTokenBridge: 0xEEd9154F63f6F0044E6b00dDdEFD895b5B4ED580

Arbitrum