hardhat-plugin/README.md

CoFHE Hardhat Plugin

A Hardhat plugin for Fully Homomorphic Encryption (FHE) development with CoFHE.

Installation

npm install fhe-hardhat-plugin
# or
yarn add fhe-hardhat-plugin
# or
pnpm add fhe-hardhat-plugin

Configuration

Add the plugin to your Hardhat config:

// hardhat.config.js or hardhat.config.ts
require("fhe-hardhat-plugin");
// or if using TypeScript
import "fhe-hardhat-plugin";

module.exports = {
  // ... other config
  fhe: {
    logMocks: true, // Optional: Set to true to log mock operations
  },
  // Network configuration is automatically added by the plugin
};

The plugin automatically adds network configurations for:

• Hardhat network with deployed mock contracts
• Ethereum Sepolia testnet
• Arbitrum Sepolia testnet

Features

Mock Contracts

This plugin uses fhe-mock-contracts to provide on-chain simulations of the CoFHE system. These mock contracts enable development and testing without requiring the actual off-chain FHE computation engine.

The mock contracts include:

• MockTaskManager: Manages FHE operations and stores plaintext values
• MockQueryDecrypter: Handles decryption requests
• MockZkVerifier: Simulates verification of encrypted inputs
• ACL: Handles access control

Key differences from the real CoFHE system:

• Operations are performed on-chain instead of off-chain
• Plaintext values are stored on-chain for testing and verification
• Decryption operations are simulated with mock delays
• Operations are logged using hardhat/console.sol

Mock Contracts Deployment

Mock contracts are automatically deployed when using the Hardhat network:

• Running tests: npx hardhat test
• Starting a local node: npx hardhat node

You can also manually deploy mock contracts:

npx hardhat deploy-mocks [--deploy-test-bed true|false] [--log-mocks true|false]

Options:

• --deploy-test-bed: Deploy the TestBed contract (default: true)
• --log-mocks: Log mock operations (default: true)

Utility Functions

The plugin exports several utility functions for working with mock contracts:

Mock Utilities

// Get plaintext value from a ciphertext hash
import { mock_getPlaintext } from "fhe-hardhat-plugin";
const plaintext = await mock_getPlaintext(provider, ctHash);

// Check if a plaintext exists for a ciphertext hash
import { mock_getPlaintextExists } from "fhe-hardhat-plugin";
const exists = await mock_getPlaintextExists(provider, ctHash);

// Test assertion for plaintext values
import { mock_expectPlaintext } from "fhe-hardhat-plugin";
await mock_expectPlaintext(provider, ctHash, expectedValue);

Network Utilities

// Get the CoFHE environment based on network name
import { getFHEEnvironmentFromNetwork } from "fhe-hardhat-plugin";
const environment = getFHEEnvironmentFromNetwork(networkName);

// Check if a CoFHE environment is permitted for a given network
import { isPermittedFHEEnvironment } from "fhe-hardhat-plugin";
const isPermitted = isPermittedFHEEnvironment(hre, environmentName);

// Initialize CoFHEjs with a Hardhat signer
import { fhe_initializeWithHardhatSigner } from "fhe-hardhat-plugin";
await fhe_initializeWithHardhatSigner(signer, options);

Usage in Tests

The plugin automatically deploys mock contracts when running tests:

import { expect } from "chai";
import { mock_expectPlaintext } from "fhe-hardhat-plugin";

describe("My FHE Contract", function() {
  it("should store encrypted value correctly", async function() {
    const [signer] = await ethers.getSigners();
    const myContract = await ethers.deployContract("MyFHEContract");

    // Interact with your contract
    const tx = await myContract.storeEncrypted(123);
    await tx.wait();

    // Get the ciphertext hash from event logs
    const ctHash = /* extract from logs */;

    // Verify plaintext value (only works on hardhat network)
    await mock_expectPlaintext(signer.provider, ctHash, 123n);
  });
});

License

MIT