Minesweeper FHE

A Fully Homomorphic Encryption (FHE) powered Minesweeper game built on fhEVM using Solidity. The game board remains encrypted on-chain, allowing players to reveal cells without exposing the full state. This project demonstrates the use of FHE for privacy-preserving gameplay in smart contracts.

Template

This project was build using the fhevm-hardhat-template

Contract Address

Contract Address on Sepolia: 0x898Cba70b3853DB431f7668068Ad38B7ce05D3f4

Usage

Pre Requisites

Install pnpm

Before being able to run any command, you need to create a .env file and set a BIP-39 compatible mnemonic as the MNEMONIC environment variable. You can follow the example in .env.example or start with the following command:

cp .env.example .env

If you don't already have a mnemonic, you can use this website to generate one. An alternative, if you have foundry installed is to use the cast wallet new-mnemonic command.

Then, install all needed dependencies - please make sure to use Node v20 or more recent:

pnpm install

Compile

Compile the smart contracts with Hardhat:

pnpm compile

TypeChain

Compile the smart contracts and generate TypeChain bindings:

pnpm typechain

Test

Run the tests with Hardhat - this will run the tests on a local hardhat node in mocked mode (i.e the FHE operations and decryptions will be simulated by default):

pnpm test

Test Logs

❯ npx hardhat test


  FHEMinesweeper
    ✔ should allow a player to start a game (40ms)
    ✔ should prevent starting a new game while one is active (67ms)
    ✔ should prevent wrong coordinates when requesting cell reveal (45ms)
Revealed cell value: 0
    ✔ should allow a player to request cell reveal and check if it's a mine or not (293ms)
    ✔ should prevent revealing a cell in an inactive game
Revealed cell at (0, 0) has value: 0
Revealed cell at (0, 1) has value: 0
Revealed cell at (0, 2) has value: 0
Revealed cell at (0, 3) has value: 0
Revealed cell at (0, 4) has value: 0
Revealed cell at (0, 5) has value: 0
Revealed cell at (0, 6) has value: 0
Revealed cell at (0, 7) has value: 0
Revealed cell at (1, 0) has value: 0
Revealed cell at (1, 1) has value: 0
Revealed cell at (1, 2) has value: 0
Revealed cell at (1, 3) has value: 0
Revealed cell at (1, 4) has value: 0
Revealed cell at (1, 5) has value: 0
Game lost! A mine was revealed.
X:  1 Y:  6
    ✔ should lose the game when a mine is revealed (233ms)


  6 passing (710ms)

Lint Solidity

Lint the Solidity code:

pnpm lint:sol

Lint TypeScript

Lint the TypeScript code:

pnpm lint:ts

Clean

Delete the smart contract artifacts, the coverage reports and the Hardhat cache:

pnpm clean

Coverage

Test Coverage for FHEMinesweeper.sol:

File	Statements	Branches	Functions	Lines
FHEMinesweeper.sol	96%	78.57%	100%	94.74%

To analyze the coverage of the tests, you can use this command:

pnpm coverage

Then open the file coverage/index.html. You can see there which line or branch for each contract which has been covered or missed by your test suite. This allows increased security by pointing out missing branches not covered yet by the current tests.

License

This project is licensed under MIT.