Provably Fair Decentralized Lottery

👤 Author

Mohd Shariq

• GitHub: @Shariq103

This is a Provably Fair Smart Contract Lottery built using Solidity and Foundry. It leverages Chainlink VRF for verifiable randomness and Chainlink Automation for time-based triggers, ensuring a completely decentralized and automated gaming experience.

Key Features

• Truly Random: Uses Chainlink VRF (Verifiable Random Function) to select a winner. No one (not even the developer) can manipulate the result.
• Automated: Uses Chainlink Automation (Keepers) to automatically trigger the winner selection after a set interval.
• Decentralized: The logic lives entirely on the blockchain (Sepolia/Ethereum).
• Gas Efficient: Optimized code structure following best practices.
• Robust Testing: Includes comprehensive Unit and Integration tests using Foundry.

Technology Stack

• Language: Solidity ^0.8.19
• Framework: Foundry (Forge, Cast, Anvil)
• Oracle Services: Chainlink VRF v2.5 & Chainlink Automation
• Network: Sepolia Testnet

Architecture

1. Enter: Players join by paying an entrance fee (ETH).
2. Wait: The lottery runs for a specific time interval.
3. Trigger: Chainlink Automation checks if the time is up.
4. Request: The contract requests a random number from Chainlink VRF.
5. Fulfill: Chainlink VRF returns a random number, and the contract calculates the winner.
6. Payout: The winner automatically receives the entire pot balance.

Getting Started

Prerequisites

• Git
• Foundry
• Make (Optional, for using Makefiles)

Installation

1. Clone the repository:

   git clone [https://github.com/](https://github.com/)[YOUR_USERNAME]/foundry-smart-contract-lottery.git
   cd foundry-smart-contract-lottery

2. Install Dependencies:

   make install
   # or
   forge install

3. Compile the contracts:

   forge build

🧪 Testing

This project includes both Unit and Integration tests to ensure reliability.

Run Unit Tests:

forge test

foundry-Lottery-Raffle