© 2004 Computer Academic Underground
Digital Imagery Basics
*Steganography using 8-bit images have a lot of hurdles to overcome *Due to the limited number of color values a single byte can represent, a color-map is generally employed *Because pixel values are mapped to colors in a table, a single bit change in the byte representing the pixel could have drastic visible effects in the image
•Using steganography with 8-bit images have a lot of hurdles to overcome.
•8-bit images use an index of colors rather than using actual color values to represent colors, and store the actual color values in a color table.
•This is also sometimes referred to as it’s color-map.
•This color-mapping creates an entire set of unique problems to overcome when manipulating bits in the image.
•A single bit change in a pixel value could potentially map to a completely different color which could drastically change the way the image looks.
•We won’t be discussing methods for using steganography with 8-bit images in this presentation and will instead be focusing on 24-bit images.