useecho 🎙️

Tamper-Proof Audio Recording with Cryptographic Verification

useecho is a revolutionary audio recording app that creates unforgeable proof of authenticity using:

• Aqua Protocol for cryptographic file verification
• Privy for seamless email authentication
• Nostr for decentralized witnessing

🌟 Features

• Record Audio in 2-second chunks with real-time verification
• Silent Signing - No annoying popups every 2 seconds
• Automatic Witnessing - Every 10 chunks witnessed on Nostr network
• Verification - Anyone can verify the entire recording chain
• Mobile Responsive - Works perfectly on phones and tablets
• No Storage Required - Download and share your recordings

🚀 Quick Start

1. Install Dependencies

npm install

2. Configure Environment

Create .env.local file:

NEXT_PUBLIC_PRIVY_APP_ID=your_privy_app_id_here
NEXT_PUBLIC_NOSTR_RELAYS=wss://relay.damus.io,wss://relay.snort.social

Get your Privy App ID from https://dashboard.privy.io

3. Run Development Server

npm run dev

Open http://localhost:3000

🎯 How It Works

Recording Flow

1. Login with email via Privy
2. Derive Nostr Keys deterministically from your signature
3. Start Recording - Audio chunks every 2 seconds
4. Automatic Processing:
   • Each chunk → Aqua file revision (genesis/content)
   • Silent signature with Privy (no popups!)
   • Hash linked to previous chunk
   • Witness on Nostr every 10 chunks
5. Download - Get audio file + Aqua proof JSON

Verification Flow

1. Upload .webm audio file
2. Upload .aqua.json proof file
3. Verify entire chain:
   • Each chunk hash validated
   • Signatures verified
   • Chain integrity checked
   • Nostr witnesses confirmed

📁 Project Structure

useecho/
├── app/
│   ├── layout.tsx          # Root layout with Privy
│   ├── page.tsx            # Recording page
│   ├── verify/page.tsx     # Verification page
│   └── providers.tsx       # Client providers
├── components/
│   ├── Header.tsx          # App header
│   └── AudioRecorder.tsx   # Main recording component
├── lib/
│   ├── aqua/
│   │   ├── aquafier.ts    # Aqua SDK wrapper
│   │   └── types.ts       # Type definitions
│   ├── nostr/
│   │   └── keys.ts        # Nostr key derivation
│   └── utils.ts           # Utilities
└── hooks/
    ├── useRecording.ts    # Recording state
    └── useNostr.ts        # Nostr operations

🔧 Tech Stack

• Framework: Next.js 14 (App Router)
• Styling: TailwindCSS
• Auth: Privy (email-only)
• Blockchain: Aqua Protocol SDK
• Witnessing: Nostr (nostr-tools)
• Icons: Lucide React

🔐 Security

• Deterministic Keys: Nostr keys derived from Privy signature (no storage)
• Silent Signing: showWalletUIs: false for seamless UX
• Chain Integrity: Each chunk cryptographically linked
• Decentralized Witnessing: Nostr relays provide timestamped proof
• No Private Key Exposure: Keys regenerated per session

🎨 Features in Detail

Silent Signing

await signMessage({ message }, {
  uiOptions: { showWalletUIs: false } // No popup!
})

Nostr Key Derivation

const sig = await signMessage({ message })
const keys = await deriveNostrKeysFromSignature(sig)
// Keys recreated deterministically each session

Chunk Processing

• 2-second audio chunks
• Genesis revision for first chunk
• Content revisions for subsequent chunks
• Automatic prev_hash linking

Witnessing Strategy

• Witness every 10 chunks (every 20 seconds)
• Post to multiple Nostr relays
• Include chunk index and verification hash
• Timestamped proof of recording time

📱 Mobile Support

Fully responsive design:

• Touch-friendly buttons
• Adaptive layouts
• Works on iOS/Android browsers

🚧 Future Enhancements

• Save Privy→Nostr mapping on Base mainnet
• IPFS storage integration
• Live streaming verification
• Advanced audio formats
• Batch verification

🏆 Built For EthSafari Hackathon

High wow factor, low complexity - leveraging:

• Aqua Protocol's revision system
• Privy's embedded wallets
• Nostr's free witnessing

📄 License

MIT

🤝 Contributing

PRs welcome! This is a hackathon project but we'd love to see it grow.

---

Built with ❤️ using Aqua Protocol, Privy, and Nostr