👻 Raven

The first P2P digital marketplace combining ZK-Proofs for Private Identities along with stealth payments for complete privacy and trust.

🎯 The Problem

Traditional P2P marketplaces face a critical dilemma:

• Trust: How do you verify sellers without compromising privacy?
• Privacy: How do you protect financial transactions from surveillance?
• Security: How do you prevent fraud while maintaining anonymity?

Current solutions force users to choose between trust and privacy. We solved both.

🚀 Our Solution

Hyena introduces Verified Anonymous E-Commerce - a revolutionary approach that combines:

🔐 Zero-Knowledge Identity Verification

• Aadhaar-based verification using Self SDK
• Proves identity elements like Uniqueness, Age & Region without revealing personal information
• One-time verification, permanent trust score

👻 Stealth Payment System

• Complete financial privacy using ERC-5564 stealth addresses
• Payments are untraceable to external observers
• Easy to Use using in Built Stealth Management

🛡️ Smart Contract Escrow

• Trustless transactions with automatic fund release
• PYUSD-based payments for stability
• Buyer & Seller protection with refund mechanisms

PYUSD For Payments

• Easy onboarding for PayPal users → mass crypto adoption
• Smooth Web2 → Web3 transition
• Market expansion for PayPal

🏗️ Architecture

┌─────────────────┐    ┌──────────────────┐    ┌─────────────────┐
│   Aadhaar ZK    │    │  Smart Contract  │    │ Stealth Payment │
│  Verification   │────│     Escrow       │────│     System      │
│                 │    │                  │    │                 │
│ • Identity Proof│    │ • Fund Security  │    │ • Private Txns  │
│ • Anonymous     │    │ • Buyer Protection│    │ • Unlinkable    │
└─────────────────┘    └──────────────────┘    └─────────────────┘

🔄 Workflow

Seller Journey

1. Identity Verification: Generate zero-knowledge proof using Aadhaar without revealing PII
2. Stealth Key Generation: Create spending/viewing key pairs for private payment reception
3. Listing Creation: Deploy escrow contract with API key and stealth meta-address
4. Payment Reception: Receive funds privately via generated stealth addresses

Buyer Journey

1. Browse Verified Listings: View services from Aadhaar-verified sellers
2. Escrow Funding: Lock PYUSD in smart contract with MetaMask transaction
3. API Access: Retrieve service credentials from escrow after payment
4. Transaction Completion: Confirm receipt to release funds to seller's stealth address

Smart Contract Flow

Create Escrow → Fund Escrow → Access API → Confirm Receipt → Release to Stealth
     ↓              ↓            ↓             ↓              ↓
  [CREATED]     [LOCKED]    [API_ACCESS]  [CONFIRMED]    [COMPLETED]

🧠 Technical Concepts

Zero-Knowledge Identity Verification

• Self SDK Integration: Generates cryptographic proofs of Indian citizenship without revealing personal data
• Nullifier System: Prevents double-verification while maintaining anonymity
• On-Chain Verification: Smart contracts validate ZK proofs without accessing sensitive information

Stealth Address Implementation

• ERC-5564 Standard: Implements standardized stealth address protocol
• Key Derivation: Uses ECDH (Elliptic Curve Diffie-Hellman) for shared secret generation
• Payment Privacy: Each transaction uses a unique, unlinkable address
• Scanning Mechanism: Sellers can detect payments using viewing keys without revealing spending keys

Escrow Smart Contract Design

• State Machine Pattern: Implements secure state transitions (Created → Locked → Completed)
• Reentrancy Protection: Uses OpenZeppelin's ReentrancyGuard for security
• Time-locked Refunds: Automatic refund mechanism after deadline expiry
• Gas Optimization: Efficient storage patterns and minimal external calls

Privacy-Preserving Architecture

• Metadata Protection: Transaction amounts and recipients are cryptographically hidden
• Unlinkability: External observers cannot connect multiple transactions to same user
• Forward Secrecy: Compromised keys don't reveal historical transaction data

✨ Key Features

• 🔒 Privacy-First: Stealth addresses ensure transaction privacy
• ✅ Trust Without KYC: Zero-knowledge Aadhaar verification
• 🛡️ Escrow Protection: Smart contract-based fund security
• 💰 Stable Payments: PYUSD integration for price stability
• 🌐 Decentralized: No central authority controls your data

🚀 Future Roadmap

Phase 1: Enhanced Privacy

• Multi-chain deployment (Polygon, Arbitrum)
• Advanced stealth payment features
• Mobile app development

Phase 2: Ecosystem Growth

• API marketplace expansion
• Reputation system integration
• Developer SDK release

Technical Stack

• Frontend: Next.js 15, TypeScript, Tailwind CSS
• Blockchain: Ethereum (Sepolia), Solidity smart contracts
• Privacy: Anon Aadhaar SDK, Fluidkey Stealth Account Kit
• Payments: PYUSD stablecoin integration
• Storage: Supabase,