Visual cryptography is a cryptographic technique that allows visual information (pictures, text, etc.) to be encrypted in such a way that the decrypted information appears as a visual image. One of the best-known techniques has been credited to Moni Naor and Adi Shamir, who developed it in 1994. They demonstrated a visual secret sharing scheme, where an image was broken up into n shares so that only someone with all n shares could decrypt the image, while any n − 1 shares revealed no information about the original image.

Visual cryptography can be used to protect biometric templates in which decryption does not require any complex computations.

Visual cryptography works by using two or more images, called shares, to encrypt an image. The shares are created by using a mathematical function to combine the pixels of the original image. The shares are then distributed to different people. To decrypt the image, the shares are overlaid on top of each other. When the shares are overlaid correctly, the original image is revealed.

Visual cryptography has a number of advantages over traditional encryption techniques. First, it is very secure. It is very difficult to guess the original image from the shares. Second, it is very easy to use. Anyone can decrypt the image with the shares. Third, it is very versatile. It can be used to encrypt any type of visual information.

Visual cryptography is a promising technology with a wide range of potential applications. It could be used to protect sensitive information, such as biometric templates, in a variety of settings, such as healthcare and law enforcement. It could also be used to create new forms of secure communication and entertainment.

Here are some of the applications of visual cryptography:

• Secure communication: Visual cryptography can be used to send secure messages. The sender can encrypt the message using a visual cryptography scheme and then send the shares to the recipient. The recipient can then decrypt the message by overlaying the shares.
• Secure voting: Visual cryptography can be used to conduct secure elections. Voters can cast their votes using visual cryptography. The votes can then be counted without revealing the identity of the voters.
• Secure identification: Visual cryptography can be used to create secure identification cards. The cards can be encrypted using visual cryptography. The card can then be decrypted by a authorized person.
• Secure storage: Visual cryptography can be used to store sensitive information. The information can be encrypted using visual cryptography and then stored in a secure location. The information can then be decrypted by authorized person.

Visual cryptography is a promising technology with a wide range of potential applications. It is a secure, easy-to-use, and versatile technology that could be used to protect sensitive information in a variety of settings.

Visual Cryptography :

Cryptography which mean secret writing. Cryptography is the process of scrambling the original text by rearranging and substituting the original text. 

Visual cryptography is a cryptographic technique which allows visual information like pictures, text to be encrypted in such a way that decryption can be done just by sight reading. Visual cryptography, degree associated rising cryptography technology, uses the characteristics of human vision to rewrite encrypted photos. Visual cryptography provides secured digital transmission that is used just for merely the once. 

Data Hiding :   Visual Cryptography : 

Proposed Image Encryption Method

Algorithm: Image Encryption

Input: Hided Image   Output: Encrypted Image 

Step 1: An input image will be selected. It must be an RGB image. 

Step 2:Red, Green and blue Channels are separated from an input Image.

Step 3: Each Channel is then further encrypted into 8 shares. This encryption will depend on key used. 

Step 4: From Step 3, we get 24 shares, it means each channel has 8 shares each. These 8 shares of an each channel then further compress to 3 shares. Thus we get an o/p of 9 shares at step 4. 

Step 5: Compress 3 Shares from step 4 to one final encrypted image.

Visual Cryptography some of them are following aplication: 

1. Secret Communication 

2. Copyright Protection

3. Document Authentication

4. Secret data storing