Getting Started

@cofhe/hardhat-plugin extends Hardhat with everything you need to build and test FHE-enabled contracts locally — mock contracts, a pre-configured CoFHE client, and test utilities.

What the plugin provides

• Mock contracts deployed automatically on every npx hardhat test / npx hardhat node run, simulating the full CoFHE coprocessor stack on the Hardhat network.
• hre.cofhe — a namespaced API for creating and connecting CoFHE clients with Hardhat signers.
• hre.cofhe.mocks — utilities for reading raw plaintext values and interacting with mock contracts directly in tests.
• Pre-configured networks — localcofhe, eth-sepolia, and arb-sepolia are injected automatically.

Installation

npm install @cofhe/hardhat-plugin

import '@cofhe/hardhat-plugin'; 
 
export default {
  solidity: '0.8.28',
};

Configuration

The plugin adds an optional cofhe key to your Hardhat config:

import '@cofhe/hardhat-plugin';
 
export default {
  solidity: '0.8.28',
  cofhe: {
    logMocks: true, // log FHE ops to the console (default: true)
    gasWarning: true, // warn when mock gas usage is high (default: true)
  },
};

Pre-configured networks

The following networks are injected automatically. You can override any of them by defining the same key under networks in your config.

For testnets, set PRIVATE_KEY (and optionally SEPOLIA_RPC_URL / ARBITRUM_SEPOLIA_RPC_URL) in your environment.

Auto-deployment

Mock contracts are deployed automatically before:

• npx hardhat test
• npx hardhat node

To skip auto-deployment (e.g., when running tests only against an external RPC):

COFHE_SKIP_MOCKS_DEPLOY=1 npx hardhat test

Next steps

• Client — Create and connect a CoFHE client in tests
• Mock Contracts — Read plaintext values and interact with mock contracts
• Logging — Inspect FHE operations in test output
• Testing — End-to-end test patterns