| Description |
Least Significant Bit steganography. An image is nothing more than strings and strings of bytes, each byte representing a different color. The last few bits in a color byte, however, do not hold as much significance as the first few. This is to say that two bytes that only differ in the last few bits can represent two colors that are virtually indistinguishable to the human eye. For example, 00100110 and 00100111 can be two different shades of red, but since it is only the last bit that differs between the two, it is impossible to see the color difference. LSB steganography, then, alters these last bits by hiding a message within them. One way of doing this is as follows. Say I wished to hide the first letter of my first name in a small section of an image. This letter is ?I,? and the ASCII for I is 01001001. As seen from the illustration, the last bit of every byte is replaced with the corresponding bit from the letter I. The bits that have been altered are underlined.The new image now contains the desired text of the ?I? without degrading the quality of the image since only the least significant bits were altered |
