Multi-Chain Transaction Signing Demo

This repository contains a demo application that demonstrates the process of signing transactions on multiple blockchain networks using a single NEAR account. The application supports signing transactions on Ethereum (ETH), Binance Smart Chain (BNB), and Bitcoin (BTC) testnets.

Features

• Sign transactions on ETH, BNB, and BTC testnets using a NEAR account
• Derive addresses for each supported chain based on a derivation path
• Check account balances on each supported chain
• Send transactions on each supported chain

Prerequisites

• Node.js
• NPM package manager
• A NEAR testnet account - Instructions to create an account: https://docs.near.org/tools/near-cli

Setup

Clone the repository:

Install the dependencies:

npm i

Set up the environment variables: Create a .env file in the root directory of the project and add the following variables:

NEXT_PUBLIC_NEAR_ACCOUNT_ID=your-near-testnet-account-id
NEXT_PUBLIC_NEAR_PRIVATE_KEY=your-near-testnet-private-key

Replace your-near-testnet-account-id with your NEAR testnet account ID and your-near-testnet-private-key with your NEAR testnet private key.

Running the Application

To start the development server, run the following command:

npm run dev

Open your browser and navigate to http://localhost:3000/multi-chain to access the application.

Usage

• Select the desired chain (ETH, BNB, or BTC) from the dropdown menu.
• Enter the derivation path for the selected chain.
• Click the "Check Balance" button to fetch the account balance on the selected chain.
• Enter the recipient's address in the "Address" field.
• Enter the amount to send in the "Value" field.
• Click the "Send Transaction" button to initiate the transaction.

Code Structure

The main components of the application are located in the following files:

• pages/index.tsx: The main page of the application that handles user interactions and state management.
• utils/chain/EVM.ts: Contains the EVM class that provides functions for interacting with Ethereum and Binance Smart Chain.
• utils/chain/Bitcoin.ts: Contains the Bitcoin class that provides functions for interacting with the Bitcoin testnet.
• utils/contract/signer.ts: Contains functions for signing transactions using the smart contract.
• utils/kdf.ts: Contains functions for key derivation.