Anonymous group gifting with encrypted contributions powered by iExec TEE and Zama FHE

ETHRome 2025 Hackathon Project

Live Demo • Documentation

SecSanta enables groups to create anonymous gift contribution pools where individual amounts remain cryptographically hidden until finalization:

1. Create a pool for a recipient (birthdays, farewells, celebrations)
2. Contributors join with encrypted contributions - amounts stay hidden from everyone
3. Auto-finalize when threshold is met - funds transfer to recipient
4. Privacy preserved - individual amounts never revealed, only the total

Traditional group gifting platforms expose contribution amounts, creating:

• Social pressure - people see what others contribute
• Bias and inequality - larger contributions visible
• Privacy concerns - financial information leaked

Two privacy modes powered by cutting-edge cryptography:

🔐 iExec Mode (Arbitrum Sepolia)

• Client-side AES-256 encryption via DataProtector SDK
• Encrypted data stored as NFTs on-chain
• TEE (Trusted Execution Environment) computation
• Contributions remain encrypted forever

🔐 Zama FHE Mode (Sepolia)

• Fully Homomorphic Encryption on smart contracts
• On-chain encrypted computation
• KMS oracle decryption at finalization
• Confidential ERC20 tokens (BCT)

Category: Confidential DeFi using DataProtector

Our Implementation:

• ✅ DataProtector SDK integration for client-side encryption
• ✅ Smart contract deployed on Arbitrum Sepolia (0xEC5Db14bFE52cF395a8778D32c25E59a2bD364B8)
• ✅ Encrypted contribution data stored as NFTs
• ✅ Real blockchain transactions with verification links
• ✅ Pool creation, contribution, and finalization all on-chain
• ✅ Transaction proofs visible on Arbiscan

Key Files:

• fe/lib/iexec-dataprotector.ts - DataProtector integration
• fe/lib/contract-service.ts - Smart contract interactions
• fe/contracts/SecSantaPool.sol - Contribution pool contract

Category: FHE-based confidential applications

Our Implementation:

• ✅ Zama fhEVM Relayer SDK integration
• ✅ BirthdayConfidentialToken (BCT) deployed on Sepolia (0xCee0c15B42EEb44491F588104bbC46812115dBB0)
• ✅ ContributionPool contract with FHE operations (0xE45d459Fc44c2B5326Bcef9F10028Bc252Bc2fd0)
• ✅ On-chain encrypted arithmetic (homomorphic addition)
• ✅ KMS oracle decryption at finalization
• ✅ Confidential token transfers using operator approvals

Key Files:

• fe/lib/zama-service.ts - Zama FHE integration
• fe/lib/zama-pool-service.ts - Pool service for FHE mode
• backend/contracts/BirthdayConfidentialToken.sol - Confidential ERC20
• backend/contracts/ContributionPool.sol - FHE contribution pool

cd fe
npm install
npm run dev

Open http://localhost:3000

Privacy Mode Toggle: Use the debug panel to switch between iExec and Zama modes

• Next.js 14 with App Router
• TypeScript for type safety
• RainbowKit + Wagmi v2 for Web3 integration
• Tailwind CSS for styling

iExec Mode (Arbitrum Sepolia):

• SecSantaPool contract manages ETH contributions
• iExec DataProtector stores encrypted amounts as NFTs

Zama Mode (Sepolia):

• BirthdayConfidentialToken (BCT) - FHE-enabled ERC20
• ContributionPool - Manages encrypted contributions with euint64

• ✅ Dual privacy modes (iExec TEE + Zama FHE)
• ✅ Encrypted contributions with cryptographic guarantees
• ✅ Individual amounts never revealed publicly
• ✅ Verifiable on-chain transactions

• ✅ Clean, modern interface
• ✅ Mobile-responsive design
• ✅ Transaction verification links (Arbiscan/Etherscan)
• ✅ Real-time pool progress tracking
• ✅ One-click pool finalization

• ✅ Deployed smart contracts on testnets
• ✅ Full integration with both privacy SDKs
• ✅ Comprehensive error handling
• ✅ Transaction proof system
• ✅ Live demo on Vercel

• Architecture Diagrams - Complete system flows with Mermaid diagrams
• Setup Guide - Installation and configuration
• Integration Details - Smart contract integration
• Demo Guide - How to demo the project

Live App: https://secsanta.vercel.app

Deployed Contracts:

• iExec Pool (Arbitrum Sepolia): 0xEC5Db14bFE52cF395a8778D32c25E59a2bD364B8
• Zama Token (Sepolia): 0xCee0c15B42EEb44491F588104bbC46812115dBB0
• Zama Pool (Sepolia): 0xE45d459Fc44c2B5326Bcef9F10028Bc252Bc2fd0

MIT License

ETHRome 2025 - Pushing the boundaries of privacy-preserving DeFi

Technologies: Next.js • iExec DataProtector • Zama fhEVM • RainbowKit • Wagmi • Solidity