Visual-Cryptography

Visual Cryptography is a cryptographic technique to encrypt visual information like images and text, which doesn’t require any sophisticated computation but a mere human sight-reading to decrypt. Visual Cryptography uses the idea of hiding secrets within images which are divided into multiple shares and then decoded by superimposing the shared images.

This is a Visual Cryptography implementation as part of Cryptography course project (CS350 and CS353). In this project, the following methods are implemented based on the types of images: binary, grayscale, and colored.

1. XOR implementation (Binary, Grayscale, and Colour)
2. Modular Arithmetic Implementation (Binary, Grayscale, and Colour)
3. Pixel expansion implementation (Binary)
4. Key + AES encryption implementation (Binary, Grayscale, and Colour)
5. Halftone CMYK Decomposition (Colour)
6. Bit-Level Decomposition (Grayscale)

We have planned to use PSNR (Peak Signal-to-Noise Ratio) and NCC (Normalized Cross-Correlation) as a metric to check how the final decrypted image is similar(or related) to the original image.

Team Members

1. Shreeraksha R Aithal (181CO149)
2. K Krishna Swaroop (181CO125)

Reference Materials

• Visual Cryptography
• Applications and usage of visual cryptography: A review
• Visual Cryptography for Gray-scale Images Using Bit-level
• An Implementation of Algorithms in Visual Cryptography in Images
• Copyright protection scheme for digital images using visual cryptography and sampling methods
• Visual Cryptography in Gray Scale Images
• A novel image encryption algorithm using AES and visual cryptography
• Visual cryptography for color images
• Improving Image Quality In Extended Visual Cryptography For Halftone Images With No Pixel Expansion