LayerZero Cross Chain Protocol

This repository contains two Solidity smart contracts that demonstrate cross-chain communication using the LayerZero protocol. These contracts are designed to operate on different Ethereum test networks and allow for message passing and token bridging between chains.

Table of Contents

1. Overview
2. Contracts
   • LayerZeroTestContract
   • LayerZeroTokenContract
3. Deployment Information
4. Usage
   • Message Sending
   • Token Bridging
5. Setup and Installation

Overview

The contracts leverage the LayerZero protocol to enable cross-chain communication. They demonstrate basic functionalities such as sending and receiving messages and transferring tokens across different chains.

LayerZeroTestContract

This contract allows sending and receiving string messages between chains. It utilizes LayerZero's NonblockingLzApp to ensure that cross-chain messages are received even if the transaction reverts.

LayerZeroTokenContract

This contract extends the ERC20 standard and the NonblockingLzApp to facilitate token bridging between chains. It allows users to burn tokens on the source chain and mint them on the destination chain.

Contracts

LayerZeroTestContract

Constructor

• constructor(address _endpoint): Initializes the contract with the LayerZero endpoint address and sets the destination chain ID based on the endpoint.

Functions

• _nonblockingLzReceive: Overrides the parent function to update the data variable with the received message.
• send(string memory _message): Encodes and sends the provided message to the destination chain.
• trustAddress(address _otherContract): Sets the trusted remote contract address for cross-chain communication.

LayerZeroTokenContract

Constructor

• constructor(address _endpoint): Initializes the contract with the LayerZero endpoint address, sets the destination chain ID, and mints an initial supply of tokens to the deployer.

Functions

• _nonblockingLzReceive: Overrides the parent function to mint tokens to the specified account on the destination chain.
• bridge(uint _amount): Burns the specified amount of tokens on the source chain and sends a message to mint them on the destination chain.
• trustAddress(address _otherContract): Sets the trusted remote contract address for cross-chain communication.

Deployment Information

• Optimism (Chain ID: 10232)

  • Endpoint: 0x55370E0fBB5f5b8dAeD978BA1c075a499eB107B8

• Arbitrum (Chain ID: 10231)

  • Endpoint: 0x6098e96a28E02f27B1e6BD381f870F1C8Bd169d3

Usage

Message Sending (LayerZeroTestContract)

1. Deploy the Contract: Deploy the contract on the desired network with the appropriate endpoint.
2. Send Message: Call the send function with the desired message. The message will be encoded and sent to the destination chain.
3. Receive Message: The _nonblockingLzReceive function on the destination chain will decode and store the received message.

Token Bridging (LayerZeroTokenContract)

1. Deploy the Contract: Deploy the contract on both the source and destination chains with the appropriate endpoints.
2. Bridge Tokens: Call the bridge function with the desired token amount. The tokens will be burned on the source chain and a message will be sent to mint them on the destination chain.
3. Mint Tokens: The _nonblockingLzReceive function on the destination chain will decode the message and mint the tokens to the specified address.

Setup and Installation

1. Clone the Repository:

   git clone https://github.com/anurag-iitk/layerzero-cross-chain.git
   cd layerzero-cross-chain

2. Install Dependencies: Make sure you have Node.js installed. Run the following command to install the required dependencies:

   npm install

3. Compile the Contracts: Use Hardhat to compile the contracts:

   npx hardhat compile

4. Deploy the Contracts: You can deploy the contracts using the Hardhat deployment scripts. Configure the network settings in hardhat.config.ts and run:

   npx hardhat run ignition/modules/deploy.ts --network <network-name>