| Unlike Cryptography, Steganography doesn't encrypts information. It just hide them. We could say that steganography is the art of hiding information inside of other data. For example, information may be hidden inside of images, sound files or videos. By means of steganography, you could hide trademark inside of images placed on the web...Let's take images for example: there are images composed by millions of colors (for example photos). Each digital image is composed by 'pixels'. Each pixel is the littlest point which can be showed by your display. A very little point. Black and whit images, just need 2 color: black and white. Each pixel may be black or white. However inside of images composed by millions of colors, each pixel can have a different color. There are images composed by 24 millions of colors. When you see an image, your eye see all pixels together. So, you can't notice if an image has 24 millions of different colors or 23.999.999! In other words, you can compress images by reducing the total number of colors. Look here:
There are 8 pixel which aren't the same inside of both of 2 pictures above...However these are very little GIF images, and they use only 256 colors. With bigger images which use 24 millions of colors, you can 'handle' a lot of pixel. Well, about steganography: you could hide information inside of an image by replace some pixels with data.
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