Gasless Transaction Forwarder

Project Overview

This project implements a Gasless Transaction Forwarder, allowing users to send ERC-20 and ERC-721 transactions without holding ETH. The system consists of a forwarder smart contract, a backend relay service, and a frontend interface for users to interact with the system.

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Table of Contents

• Architecture
• Features
• Setup Guide
• Project Structure
• Privacy Measures
• Technologies Used
• Security Considerations
• Our Team
• Deployment

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Architecture

The solution consists of three main components:

1. Smart Contracts (Solidity):

   • GaslessForwarder.sol: The core contract that relays transactions on behalf of users.
   • MockRecipient.sol: A sample contract for testing the forwarder's functionality.

2. Backend (Go):

   • Responsible for relaying signed transactions to the blockchain.
   • Handles user requests for balance and transaction history.

3. Frontend (React/React Native):

   • Provides a simple UI for users to input transaction details and submit them for forwarding.

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Features

• Gasless Transactions: Users can send transactions without needing ETH.
• Multi-token Support: Supports both ERC-20 and ERC-721 tokens.
• User-friendly UI: Simple interface to input and track transactions.
• Security: Implements signature verification to ensure transaction authenticity.
• Auditable: Designed to achieve a high Solidity Shield audit score.

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Setup Guide

Environment Variables

Contracts

Create a .env file in the contracts directory with the following content:

SEPOLIA_URL=https://sepolia.infura.io/v3/02084dda02bc47f78913a11ea476be56
DEPLOYER_PRIVATE_KEY=your_secret_deployer_private_key
ETHERSCAN_API_KEY=K1PCV6JTTPBVJBGNBPRNWED435CVBH5AJD

Backend

Create a .env file in the backend directory with the following content:

INFURA_RPC_URL=https://sepolia.infura.io/v3/02084dda02bc47f78913a11ea476be56
FORWARDER_CONTRACT_ADDRESS=0x8336Fe9c782C385D888DA4C3549Aa3AADb801FAC
RELAYER_PRIVATE_KEY=you_relayer_private_secret_key
PORT=4000
PRIVATE_KEY=you_relayer_private_secret_key
CHAIN_ID=11155111
ERC721_CONTRACT_ADDRESS=0x8336Fe9c782C385D888DA4C3549Aa3AADb801FAC
ETHERSCAN_API_KEY=K1PCV6JTTPBVJBGNBPRNWED435CVBH5AJD

Prerequisites

Ensure you have the following installed:

• Node.js (v18+)
• Go (v1.19+)
• Hardhat (for smart contract deployment)
• MetaMask (for frontend testing)

1. Clone the repository

git clone <repo_url>
cd Gasless-Forwarder-main

2. Smart Contracts

cd contracts
npm install
npx hardhat compile
npx hardhat test
npx hardhat run scripts/deploy.js --network <network>

3. Backend

cd backend
go mod tidy
go run main.go

4. Frontend

cd frontend
npm install
npm run dev

5. React Native App

cd "React Native App"
npm install
npx expo start

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Project Structure

Gasless-Forwarder-main/
│-- contracts/              # Solidity smart contracts
│-- backend/                # Go backend service
│-- frontend/               # React frontend
│-- React Native App/       # Mobile frontend (React Native)
│-- README.md               # Project documentation
│-- LICENSE                 # License file

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Privacy Measures

• Off-chain Signing: Users sign transactions off-chain to avoid exposing private keys.
• Data Minimization: Only necessary transaction data is stored.
• Secure Relayer: Ensures transactions are relayed securely without tampering.

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Technologies Used

• Frontend: React, React Native, TailwindCSS
• Backend: Go, Gin framework
• Smart Contracts: Solidity, Hardhat
• Blockchain: Ethereum, MetaMask integration
• Security: ECDSA signature verification

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Security Considerations

• Signature Verification: Ensures transactions are authorized by the sender.
• Reentrancy Protection: Smart contracts are safeguarded against reentrancy attacks.
• Gas Optimization: Efficient contract design to minimize gas costs.

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Project Demonstration

Watch our project demonstration video here: YouTube

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Deployment

Watch our project demonstration video here: YouTube

• Backend: Deployed on Railway.app
• Frontend: Deployed on Vercel

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Acknowledgment

Special thanks to HACKIITK for organizing this hackathon.

Our Team

We are a dedicated team of blockchain developers, cloud/backend developers, full stack developers, software engineers, and security experts passionate about decentralized finance and improving blockchain accessibility. Our goal is to create seamless, secure, and efficient blockchain solutions.

• Shivam

• Ritik Gupta

• Sanskar Soni

• Parth Agarwal

• Ashish Verma

  

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