QR Code Steganography
Hide secret messages in plain sight using QR code error correction capacity
🔐 Encode
Create a QR code with a hidden message
🔍 Decode
Extract the hidden message from a QR code
Upload QR Code
Click to upload or drag and drop
PNG, JPG or any image format
Results
Primary Message
Secondary Message (Hidden)
How It Works
QR codes include error correction data that allows them to be read even when partially damaged. This tool exploits that error correction capacity to hide a secondary message within a normal QR code.
- ✅ Primary message readable by all standard QR scanners
- 🔒 Secondary message only extractable with this decoder
- 📊 Capacity: ~7 bytes for typical URLs
- 🎯 Uses high error correction level (Level H, 30%)
Use Cases
🎮 Scavenger Hunts
Hide bonus clues and point values that only players with the decoder can access.
💼 Product Authentication
Embed warranty codes and batch numbers invisible to counterfeiters.
🎫 Event Invitations
Public event URL with hidden VIP access codes for special guests.
🔐 Two-Factor Auth
Public session ID with hidden cryptographic challenge token.
Technical Details
This implementation uses the Nayuki QR Code generator library and exploits Reed-Solomon error correction capacity. The hidden message is encoded by intentionally flipping specific data modules within the error correction threshold, distributed using prime number stepping to avoid visual clustering.