This project is a starter repository for developing FHE (Fully Homomorphic Encryption) smart contracts on the LuxFHE network using CoFHE (Confidential Computing Framework for Homomorphic Encryption).

Prerequisites

Node.js (v18 or later)
pnpm (recommended package manager)

Installation

Clone the repository:

git clone https://github.com/luxfheprotocol/fhe-hardhat-starter.git
cd fhe-hardhat-starter

Install dependencies:

pnpm install

Available Scripts

Development

pnpm compile - Compile the smart contracts
pnpm clean - Clean the project artifacts
pnpm test - Run tests on the local CoFHE network
pnpm test:hardhat - Run tests on the Hardhat network
pnpm test:localfhe - Run tests on the local CoFHE network

Local CoFHE Network

pnpm localfhe:start - Start a local CoFHE network
pnpm localfhe:stop - Stop the local CoFHE network
pnpm localfhe:faucet - Get test tokens from the faucet
pnpm localfhe:deploy - Deploy contracts to the local CoFHE network

Contract Tasks

pnpm task:deploy - Deploy contracts
pnpm task:addCount - Add to the counter
pnpm task:getCount - Get the current count
pnpm task:getFunds - Get funds from the contract

Project Structure

contracts/ - Smart contract source files
- Counter.sol - Example FHE counter contract
- Lock.sol - Example time-locked contract
test/ - Test files
ignition/ - Hardhat Ignition deployment modules

`fhe` and `fhe-hardhat-plugin`

This project uses fhe and the CoFHE Hardhat plugin to interact with FHE (Fully Homomorphic Encryption) smart contracts. Here are the key features and utilities:

fhe Features

Encryption/Decryption: Encrypt and decrypt values using FHE

import { fhe, Encryptable, FheTypes } from 'fhe/node'

// Encrypt a value
const [encryptedInput] = await fhe.encrypt(
	(step) => {
		console.log(`Encrypt step - ${step}`)
	},
	[Encryptable.uint32(5n)]
)

// Decrypt a value
const decryptedResult = await fhe.decrypt(encryptedValue, FheTypes.Uint32)

Unsealing: Unseal encrypted values from the blockchain

const unsealedResult = await fhe.unseal(encryptedValue, FheTypes.Uint32)

`fhe-hardhat-plugin` Features

Network Configuration: Automatically configures the fhe enabled networks

Wallet Funding: Automatically funds wallets on the local network

import { localfheFundWalletIfNeeded } from 'fhe-hardhat-plugin'
await localfheFundWalletIfNeeded(hre, walletAddress)

Signer Initialization: Initialize fhe with a Hardhat signer

import { fhe_initializeWithHardhatSigner } from 'fhe-hardhat-plugin'
await fhe_initializeWithHardhatSigner(signer)

Testing Utilities: Helper functions for testing FHE contracts

import { expectResultSuccess, expectResultValue, mock_expectPlaintext, isPermittedFHEEnvironment } from 'fhe-hardhat-plugin'

Environment Configuration

The plugin supports different environments:

MOCK: For testing with mocked FHE operations
LOCAL: For testing with a local CoFHE network (whitelist only)
TESTNET: For testing and tasks using arb-sepolia and eth-sepolia

You can check the current environment using:

if (!isPermittedFHEEnvironment(hre, 'MOCK')) {
	// Skip test or handle accordingly
}

Links and Additional Resources

`fhe`

fhe is the JavaScript/TypeScript library for interacting with FHE smart contracts. It provides functions for encryption, decryption, and unsealing FHE values.

Key Features

Encryption of data before sending to FHE contracts
Unsealing encrypted values from contracts
Managing permits for secure contract interactions
Integration with Web3 libraries (ethers.js and viem)

`fhe-mock-contracts`

fhe-mock-contracts provides mock implementations of CoFHE contracts for testing FHE functionality without the actual coprocessor.

Features

Mock implementations of core CoFHE contracts:
- MockTaskManager
- MockQueryDecrypter
- MockZkVerifier
- ACL (Access Control List)
Synchronous operation simulation with mock delays
On-chain access to unencrypted values for testing

Integration with Hardhat and fhe

Both fhe and fhe-hardhat-plugin interact directly with the mock contracts:

When imported in hardhat.config.ts, fhe-hardhat-plugin injects necessary mock contracts into the Hardhat testnet
fhe automatically detects mock contracts and adjusts behavior for test environments

Mock Behavior Differences

Symbolic Execution: In mocks, ciphertext hashes point to plaintext values stored on-chain
On-chain Decryption: Mock decryption adds simulated delays to mimic real behavior
ZK Verification: Mock verifier handles on-chain storage of encrypted inputs
Off-chain Decryption: When using fhe.unseal(), mocks return plaintext values directly from on-chain storage

License

MIT

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

README.md

LuxFHE CoFHE Hardhat Starter