Getting Started

Build privacy-preserving smart contracts using Fully Homomorphic Encryption.

What is FHEVM?

FHEVM (Fully Homomorphic Encryption Virtual Machine) enables computations on encrypted data without decrypting it. This means smart contracts can process sensitive information (balances, votes, bids) while keeping the actual values hidden from everyone - including validators and node operators.

Key benefits:

• Private state variables that remain encrypted on-chain

• Confidential transactions without revealing amounts

• Sealed-bid auctions where bids stay hidden until reveal

• Private voting where individual votes are never exposed

Prerequisites

• Node.js 18.0 or higher

• npm 9.0 or higher

Verify your installation:

node --version  # Should be v18.x or higher
npm --version   # Should be 9.x or higher

Quick Start

npx create-labz

No installation required. Select a template and start building.

Or specify directly:

npx create-labz counter my-project
cd my-project
npm install
npx hardhat test

Project Structure

After running create-labz, you get:

my-project/
├── contracts/
│   └── Counter.sol       # FHEVM smart contract
├── test/
│   └── Counter.test.ts   # TypeScript test suite
├── deploy/
│   └── deploy.ts         # Deployment script
├── hardhat.config.ts     # Hardhat configuration
├── tsconfig.json         # TypeScript configuration
├── package.json          # Dependencies
└── .gitignore

Running Tests

cd my-project
npm install
npx hardhat test

Tests run on a local FHEVM mock environment. You'll see encrypted operations being performed and verified.

Deployment

Deploy to Zama devnet:

npx hardhat run deploy/deploy.ts --network zama

For other networks, configure them in hardhat.config.ts.

Templates

Category	Examples
Basics	Counter, Add, Multiply, Bitwise, Boolean
Encryption	Single value, Multiple values
Decryption	User decrypt, Public decrypt
Access Control	FHE.allow, FHE.allowThis, FHE.allowTransient
Input Proofs	Proof validation patterns
Anti-Patterns	Common mistakes to avoid
Handles	Handle lifecycle, Symbolic execution
OpenZeppelin	ERC7984, Wrappers, Vesting, AMM
Advanced	Auction, Voting, Lottery, Poker, Dark Pool

Difficulty Levels

• Beginner - Simple concepts, minimal code

• Intermediate - Multiple FHE operations combined

• Advanced - Complex patterns with decryption flows

Resources

• FHEVM Documentation

• Lab-Z GitHub

• OpenZeppelin Confidential Contracts