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Figure from:Exploring steganography: Seeing the unseen

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(with the exception of JPEG images). All tions for the pixels are derived from three color varia- primary col- ors: red, green, and blue. Each primary color is represented by 1 byte; 24-bit images use 3 bytes per pixel to represent a color value. These 3 bytes can be represented as hexadecimal, decimal, and ues. In many Web pages, the background binary val- color is rep- resented by a six-digit hexadecimal number— actually three pairs representing red, green, and b ue. A white background would have the value FFFFFF: 100 per- cent red (FF), 100 percent green (FF), and 100 percent blue (FF). Its decimal value is 255, 255, 255, and its binary value is 11111111, 11111111, 11111111, which are the three bytes making up white.
(with the exception of JPEG images). All tions for the pixels are derived from three color varia- primary col- ors: red, green, and blue. Each primary color is represented by 1 byte; 24-bit images use 3 bytes per pixel to represent a color value. These 3 bytes can be represented as hexadecimal, decimal, and ues. In many Web pages, the background binary val- color is rep- resented by a six-digit hexadecimal number— actually three pairs representing red, green, and b ue. A white background would have the value FFFFFF: 100 per- cent red (FF), 100 percent green (FF), and 100 percent blue (FF). Its decimal value is 255, 255, 255, and its binary value is 11111111, 11111111, 11111111, which are the three bytes making up white.
Figure 1. N€Preseitla= tive color palettes. (a) A256-color red palette and (b) a 256- color Renoir palette. The Renoir palette is so named because it comes from a 256- color version of Pierre-Auguste Renoir’s “Le Moulin de la Galette.” tions: visually differentiating between many of these colors is difficult. Figure 1b shows subtle color changes as well as those that seem drastic.
Figure 1. N€Preseitla= tive color palettes. (a) A256-color red palette and (b) a 256- color Renoir palette. The Renoir palette is so named because it comes from a 256- color version of Pierre-Auguste Renoir’s “Le Moulin de la Galette.” tions: visually differentiating between many of these colors is difficult. Figure 1b shows subtle color changes as well as those that seem drastic.
visually but that may vary by one bit.$ These tools take a similar approach with gray-scale images. However, the resulting stego-images as applied with S-Tools are no longer gray-scale. Instead of sim- ply going with adjacent colors as EzStego does, S-Tools manipulates the palette to produce colors that havea difference of one bit. For example, in anormal gray-scale image, white will move to black with the following RGB triples
visually but that may vary by one bit.$ These tools take a similar approach with gray-scale images. However, the resulting stego-images as applied with S-Tools are no longer gray-scale. Instead of sim- ply going with adjacent colors as EzStego does, S-Tools manipulates the palette to produce colors that havea difference of one bit. For example, in anormal gray-scale image, white will move to black with the following RGB triples
Figure 4. The satellite image we tested is of a major Soviet strategic bomber base (http://edcwww. cr. usgs. gov/dclass).
Figure 4. The satellite image we tested is of a major Soviet strategic bomber base (http://edcwww. cr. usgs. gov/dclass).
Figure 6. The Shakespeare cover file example (access http://daphne. palomar.edu/shakespeare/life. htm). Figure 5. The Renoir cover file example (access http://www. hs. port. ac. uk/wm/paint auth/renoir/moulin-galette/).
Figure 6. The Shakespeare cover file example (access http://daphne. palomar.edu/shakespeare/life. htm). Figure 5. The Renoir cover file example (access http://www. hs. port. ac. uk/wm/paint auth/renoir/moulin-galette/).
Figure 7. The result of embedding the text in the Shakespeare cover with StegoDos. S-Tools
Figure 7. The result of embedding the text in the Shakespeare cover with StegoDos. S-Tools
Figure 8. The Renoir cover file after the Airfield image was embedded with White Noise Storm. The palette has shifted severely.
Figure 8. The Renoir cover file after the Airfield image was embedded with White Noise Storm. The palette has shifted severely.
Figure 9. The result of embedding the Airfield image in the Renoir cover with S-Tools.
Figure 9. The result of embedding the Airfield image in the Renoir cover with S-Tools.
Figure 10. Result of embedding the Airfield image in the 8-bit Renoir with S-Tools. In the process, the cover image was reduced from 248 to 32 unique colors.
Figure 10. Result of embedding the Airfield image in the 8-bit Renoir with S-Tools. In the process, the cover image was reduced from 248 to 32 unique colors.
Figure 11. (a) Palette of the 8-bit Renoir cover image before embedding the Airfield image; (b) palette of the 8-bit Renoir cover image after embedding the Airfield image.
Figure 11. (a) Palette of the 8-bit Renoir cover image before embedding the Airfield image; (b) palette of the 8-bit Renoir cover image after embedding the Airfield image.