LotteryDapp — Secure, Fair Blockchain Lottery
Overview
LotteryDapp is a blockchain-based lottery where players join by paying an entry fee.
At set intervals, a random winner is picked using Chainlink VRF, ensuring results are provably fair.
No central authority controls the draw or payouts — all logic runs in a public smart contract.
Key Features
- Provably Fair Randomness — Winner selected via Chainlink VRF.
- Automated Draws — Supports Chainlink Keepers or manual triggers.
- Simple Entry — Call
enter()with the entry fee to join. - Full Pot Payout — Winner receives the collected funds.
- Event Tracking — Emits events for entries, draws, and payouts.
- Live Frontend — React.js UI showing pot size, players, and past winners.
Security Highlights
- Randomness Integrity — No block-based randomness; VRF prevents prediction or manipulation.
- Safe Payouts — Uses Checks-Effects-Interactions pattern with optional pull payments.
- Access Control — Only authorized admin can change key settings; ownership can be renounced.
- Gas Safety — No unbounded loops; player limit keeps transactions efficient.
- Recovery Mode — Handles oracle failure with refund or manual draw options.
Limitations
- Sybil Risk — One address = one entry, but users can create multiple addresses.
- Oracle Dependency — Requires Chainlink VRF for randomness; fallback needed if unavailable.
Tech Stack
- Solidity — Core lottery logic.
- Hardhat — Development & testing.
- Ethers.js — Blockchain interaction.
- React.js — Frontend UI.
- Chainlink VRF + Keepers — Randomness & automation.