Now a second command-line program is used to retrieve the data from the modified image. The command-line argument is the filename of the modified file. A common misconception is that one must have access to the original image in order to extract the data, but this is not the case. The "desteganography" program simply reads all the low-order bits of the binary representations of the pixel values as ASCII characters. If the program reads in ASCII character 7 (the "beep" character), it knows that it has reached the end of the message.
Figure 3. An example run of the program in the terminal.
