Lottery DApp

A block-chain based Lottery System made using Truffle

Features

• The owner of the Lottery contract sets a SHA3 hash of the winning guess between 1 and 1'000'000

• In order to participate a user sends required amount in ETH to the contract and gets 1 participation token per ETH in return

• The users makes guess using the makeGuess() function of the contract, 1 token is deducted for each guess

• The Lottery contract has a closeGame() function that the owner can invoke to stop any further guessing

• The unused tokens are not reimbursed

• A function winnerAddress() returns the address of the winner once the game is closed

• Once the game is closed the winner can call getPrice() to collect 50% of the ETH in the contract

• The getPrice() function sends the remaining 50% of ETH to the owner of the contract

• The owner receives all the money that contract holds if there are no correct guesses

Setup

• Clone repo: git clone [email protected]:ankitkataria/Lottery-DApp.git

• Change directory to cloned copy and run: npm install

• Install truffle: npm install -g truffle

• Download Ganache AppImage

• Run ganache AppImage

• Set the winning guess in migrations/2_add_lottery_contract.js

• Compile truffle contracts: truffle compile

• Migrate truffle contract to blockchain: truffle migrate

• Run server: npm run dev

• Open http://localhost:8080 in browser

Todo

• Add current lottery state to local storage
• Add functionality to reimburse tokens once game is closed

References

• Ethereum White Paper
• Truffle Docs
• CrypotZombies
• Bitcoin Paper