Carbon - EVM Contracts

This repository contains the Ethereum (and all EVM-compatible chain) deposit and wrapped native token (SWTH) contracts for Carbon via the Polynetwork bridge.

Setup

• Ensure you're using node v12, it does not work with node v14

1. Install Truffle ~5.1.5

npm install -g truffle@5.1.5

2. Install Ganache-CLI ^6.9.1

   npm install -g ganache-cli

3. Install Solhint ^2.1.0

   npm install -g solhint

4. Run Ganache-CLI with:

   ganache-cli -m "ladder soft balcony kiwi sword shadow volcano reform cricket wall initial normal" -p 7545 -l 8000000

5. Install node modules with npm install

6. Run truffle migrate to deploy the contracts to Ganache

7. Run truffle test to run test files

8. truffle test test/TestVault/*.js can be used to test files in a folder

LockProxy

The LockProxy contract at contracts/LockProxy.sol is a variation of PolyNetwork's LockProxy, and is intended to interact with the CCM (CrossChainManager) contract of the PolyNetwork.

The main purpose of the contract is to facilitate deposits and withdrawals into Switcheo TradeHub, which can be considered to be a side-chain.

Deposits

To perform a deposit, the asset to be deposited must first be registered. This is done through governance on Switcheo TradeHub, and will result in LockProxy.registerAsset being called by the CCM contract.

This registration associates an asset by its Ethereum address to a corresponding proxy address and asset hash on Switcheo TradeHub. For example, there could be an asset with asset hash 0x746f6b656e under Switcheo TradeHub proxy 0x213a5f9f0477b2cfc3a65120971a027e10f9a7ab. If we want this asset to represent an Ethereum token with Ethereum address: 0xc86e930a5f5cb9230aef750665161b0bfff55484, we would register 0xc86e930a5f5cb9230aef750665161b0bfff55484 and associate it to 0x213a5f9f0477b2cfc3a65120971a027e10f9a7ab and 0x746f6b656e using LockProxy.registerAsset.

After the asset is registered, LockProxy.lock can be called to perform a deposit. This would require the user to have ETH in their address and to call the function using their own address.

Wallet Contract

For the user's convenience, an alternative deposit flow that does not require the user to have ETH is provided. To use this flow, the LockProxy.getWalletAddress function can be called to get a fixed deposit address based on an Ethereum address controllable by the user and a Switcheo TradeHub address.

The user can then send ETH or any supported Ethereum tokens to the deposit address. Any Ethereum token that implements the ERC20 balanceOf and transfer functions should be supported.

After the tokens are in the deposit address, any Ethereum address can call LockProxy.createWallet to create a Wallet contract at the deposit address.

To transfer the funds from the Wallet to the LockProxy, LockProxy.lockFromWallet can be called by any Ethereum address, as long as the owner of the Wallet signs a message authorizing the deposit.

LockProxy.lockFromWallet has feeAddress and feeAmount parameters, and it is intended that the Ethereum address that calls createWallet and lockFromWallet would collect fees through specifying those parameters.

The possibility of having a separate "WalletFactory" contract and "LockProxy" contract was considered as this could allow a single wallet to interact with multiple "LockProxy" contracts if needed, while still maintaining a single deposit address.

However, this structure would be more complicated, and if a new "LockProxy" is required, then it is likely a new "Wallet" contract would be required as well. So, for simplicity, the "LockProxy" contract acts as the "WalletFactory".

Withdrawals

Withdrawals are initiated on Switcheo TradeHub, and would result in the LockProxy.unlock function being called by the CCM contract, the funds would then be transferred to the specified withdrawal address.

To send ETH, call is used instead of transfer. This follows the recommendation from this report, since the withdrawal address could be a contract.

Extensions

To allow the funds in the LockProxy to be used for future features, the addExtension method is provided. This method is intended to be called through the governance on Switcheo TradeHub.

A contract added as an extension can call LockProxy.transferToExtension which would transfer ETH to or approve tokens for the specified receivingAddress.

Extensions can be removed by the removeExtension method, also callable through Switcheo TradeHub governance.

Addresses

Ethereum

Devnet LockProxy (Rinkeby): check telegram chat

Mainnet LockProxy: 0x9a016ce184a22dbf6c17daa59eb7d3140dbd1c54

Redeploy to devnet

Update scripts/deploy_lockproxy.js, ccmProxyAddress and counterpartChainId when necessary.

npx hardhat run scripts/deploy_lockproxy.js

Update scripts/deploy_bridgeentrance.js, lockProxyAddress when necessary.

npx hardhat run scripts/deploy_bridgeentrance.js

Verify contract

Update addresses to verify

npx hardhat run scripts/verify.js

Get wallet byte code hash

npx hardhat run scripts/getwalletbytecodehash.js