Visual Secret Sharing & Additive Schemes
Explore XOR-based additive sharing and visual cryptography schemes.
Visual Cryptography Overview
Visual secret sharing (Naor & Shamir, 1994) splits an image into n transparencies such that overlaying k transparencies reveals the secret image, while any fewer reveal nothing — even to a computationally unbounded adversary.
2-of-2 Visual Scheme
Each pixel of the secret is expanded into a 2x2 block. For a black pixel: both shares get complementary patterns (when stacked, all black). For a white pixel: both shares get the same pattern (when stacked, 50% black = grey). The eye perceives the difference.
All lessons in this course
- The Secret Sharing Problem
- Shamir's Secret Sharing: Polynomial Math
- Visual Secret Sharing & Additive Schemes
- Threshold Signatures & Real-World Use Cases