zkTruth — Proof of Capture
Fight misinformation with cryptographic proof of reality.
zkTruth is a decentralized camera application that cryptographically proves media authenticity using zero-knowledge proofs and blockchain timestamping on World Chain.
In a world where AI-generated deepfakes are indistinguishable from reality, zkTruth establishes trust at the point of capture — not after the fact.
The Problem
- 4.7B AI-generated images created in 2025 alone
- 67% of people can't distinguish real from AI content
- 96% of deepfakes are created without consent
No existing solution simultaneously verifies that content was captured by a real device, at a specific time and place, by a verified human, and has not been tampered with since capture.
How It Works
📸 CAPTURE → 🔐 VERIFY → ⛓ MINT & SHARE
1. Capture
Take a photo or video. GPS coordinates, UTC timestamp, and device metadata are embedded in real-time.
2. Verify
Authenticate with World ID using zero-knowledge proofs. Prove you're human without revealing your identity.
3. Mint & Share
SHA-256 content hash is minted as an ERC-721 NFT on World Chain (Chain ID: 480). Share your verified proof on any platform.
Key Features
| Feature | Description |
|---|
| Zero-Knowledge Proof | World ID verifies you're human without revealing identity |
| Content Hashing | SHA-256 tamper-proof fingerprint generated at capture time |
| On-Chain Record | Immutable timestamp and proof on World Chain |
| Real-Time Metadata | GPS, time, device info overlaid on camera view |
| Social Sharing | Export verified proof to X, Instagram, Farcaster |
| Photo & Video | Supports both photo capture and video recording |
| Mobile-First PWA | Optimized for iPhone/Android with native camera access |
Technology Stack
| Layer | Technology | Purpose |
|---|
| Frontend | Next.js 16 + React 19 | PWA camera application |
| Identity | World ID (ZKP) | Human verification |
| Integrity | SHA-256 + C2PA (Phase 2) | Tamper detection |
| Blockchain | World Chain (ID: 480) | Immutable proof storage |
| Wallet | Privy (embedded wallets) | Non-custodial wallet |
| Storage | Arweave / Irys (Phase 2) | Permanent media storage |
Getting Started
Prerequisites
Installation
git clone https://github.com/manmos104/zktruth.git
cd zktruth
npm install --legacy-peer-deps
Development
# HTTP (desktop browser testing)
npm run dev
# HTTPS (required for mobile camera access)
npx next dev --experimental-https -p 3000
Open https://localhost:3000 in your browser.
Mobile Testing
- Run HTTPS dev server:
npx next dev --experimental-https -p 3000
- Find your local IP:
ipconfig getifaddr en0
- Open
https://<your-ip>:3000 on your phone's browser
- Accept the self-signed certificate warning
Architecture
┌─────────────────────────────────────────────┐
│ zkTruth App │
│ (Next.js PWA / React 19) │
├──────────┬──────────┬───────────────────────┤
│ Camera │ Metadata │ UI / Sharing │
│ Module │ Overlay │ Module │
├──────────┴──────────┴───────────────────────┤
│ Proof of Capture Engine │
│ ┌────────┐ ┌─────────┐ ┌────────────────┐ │
│ │SHA-256 │ │World ID │ │ GPS + Time │ │
│ │Hashing │ │ (ZKP) │ │ Capture │ │
│ └────┬───┘ └────┬────┘ └───────┬────────┘ │
│ └──────────┼──────────────┘ │
│ ▼ │
│ Proof Structure (JSON) │
├──────────────────────────────────────────────┤
│ World Chain (ID: 480) │
│ ERC-721 NFT + Immutable Timestamp │
└──────────────────────────────────────────────┘
Roadmap
Phase 1: MVP ✅ Complete
Phase 2: On-Chain Infrastructure 🔄 In Progress
Phase 3: Ecosystem & Scale 📋 Planned
Use Cases
- 🏛 Citizen Journalism — Verify war zone footage and eyewitness reports
- ⚖️ Legal Evidence — Tamper-proof photographic evidence for courts
- 🌱 Environmental Monitoring — Authenticated deforestation/pollution records
- 🎨 Content Authenticity — Creators prove original authorship vs AI copies
- 🗳 Election Monitoring — Verified records of polling stations
Security Model
| Threat | Mitigation |
|---|
| Content manipulation | SHA-256 hash detects any modification |
| Identity spoofing | World ID biometric uniqueness (1 person = 1 ID) |
| Timestamp manipulation | Blockchain consensus on World Chain |
| Metadata forgery | On-device capture binding |
Honest Limitations
zkTruth proves when, where, and by whom media was captured, and that it hasn't been modified. It does not verify the semantic meaning of content (e.g., photographing a screen showing fake content).
Project Links
License
MIT License — see LICENSE for details.
