Encrypted Santa

A Secret Santa application built on Fhenix using Fully Homomorphic Encryption (FHE). Assignments are encrypted on-chain, ensuring no one can see who got whom until the reveal.

Features

• FHE-Encrypted Assignments: Secret Santa pairings are computed and stored encrypted on-chain
• Password-Protected Games: Optional password protection using encrypted comparison
• On-Chain Randomness: Participant entropy contributes to shuffle randomness
• Permit-Based Decryption: Only participants can decrypt their own assignments

Project Structure

packages/
├── hardhat/          # Smart contracts (Solidity + FHE)
└── nextjs/           # Frontend (Next.js + wagmi + cofhejs)

Getting Started

Prerequisites

• Node.js 18+
• Bun (recommended) or npm

Installation

bun install

Environment Setup

Copy the example env files:

cp packages/hardhat/.env.example packages/hardhat/.env
cp packages/nextjs/.env.example packages/nextjs/.env.local

Configure your environment variables:

• DEPLOYER_PRIVATE_KEY - Private key for contract deployment
• NEXT_PUBLIC_WALLET_CONNECT_PROJECT_ID - WalletConnect project ID

Development

Start the frontend:

cd packages/nextjs
bun dev

Deployment

Deploy contracts to Fhenix Helium testnet:

cd packages/hardhat
bun hardhat deploy --network testnet

How It Works

1. Create Game: Creator sets a name and optional password, providing initial entropy
2. Join Game: Players join with password (if required) and contribute entropy
3. Finalize: Creator finalizes the game, triggering the encrypted shuffle
4. Reveal: Participants decrypt their individual assignments using FHE permits

Tech Stack

• Blockchain: Fhenix (FHE-enabled EVM)
• Smart Contracts: Solidity with Fhenix FHE library
• Frontend: Next.js 14, TypeScript, Tailwind CSS
• Web3: wagmi, viem, cofhejs

License

MIT