What is Visual Cryptography

What is Visual CryptographyYou have come across pictures and symbols like this, but you have often ignored them because either they don't make sense to you or second, you thought that this some sort of cryptic computer scan code. Well, pictures like these are not just white noise, often a part of visual cryptography. Visual Cryptography is a system by which information such as picture and text can be decrypted without the use of a computer, visually by just human eye. Visual Cryptography often consists of two or more pieces such as pictures or parts of text, which as an individual piece do not make any sense. However, when combined with the second or more pieces of the Visual Cryptogram, reveals a message, picture or another form of sensible information. In this article we will discuss visual cryptography and demonstrate it using some examples.

Two transparencies are often used to carry each piece of a visual cryptograph, when super imposed on each other they reveal information. A typical example of visual cryptography can be the four digit PIN for your credit card often sent to you by Banks or Credit Card companies. They are often sent printed on two small transparencies separately, the message is only reveled when you superimpose those on top of each other.

The following image is first part of the two images, as you can see by itself the image makes no sense at all.

Image 1 of 2 of a Visual Cryptograph

The following is the second part of the two part cryptographic image which again just like the first image, does not make any sense by itself.

Image 2 of 2 of a Visual Cryptogram used in Visual Cryptography

Here is the final image that you get by super imposing the first image on top of the other, as they come completely together, sensible information is revealed.

The overlayed image of a visual cryptograph which reveals a secret message

The visual cryptography images above on this article are a coutesy of the following website:

http://users.telenet.be/d.rijmenants/en/visualcrypto.htm