Visual cryptography is a cryptographic technique which allows optical information (pictures, text, etc.) to be encrypted in such a way that decryption becomes an automatic operation that does not require a computer.
- Visual cryptography is one of the techniques used in recent times to sustain the top secret message broadcast.
- Intricacy of encryption and decryption method is reduced in this technique and also two way communication can be achieved very steadily.
- Halftone visual cryptography, watermarking visual cryptography, extended visual cryptography using complementary are the different techniques.
- Shares pair, secondary black pixels and parallel error diffusion are also used.
- It is a secret-sharing technique that encrypts a secret picture into numerous shares but requires neither computer nor calculations to decrypt the secret image.
- Reconstruction of the secret image is done visually: simply by overlaying the encrypted shares the secret image becomes clearly visible.
- Easy to implement.
- Hard problem dependency is not required while encryption.
- No decryption algorithm required, anyone can decrypt the message.
- FAX or E-MAIL is the mode of transmitting the cipher text.
- The message cannot be predicted by infinite computation method.
Real Time Examples
- Customer Identification in Banks.
- Anti – spam bot.
- Electronic voting Machine.
- Colored digital watermarks.