The practice of hiding information in e-pictures, MP3 music files, or any binary data format that can be changed without invalidating the data format as well as retain the appearance of being unaltered. Steganography is successful because it is based on the fact that digital images and MP3 music files are comprised of thousands of pieces of binary code instructing a computer to color a pixel or to produce a certain sound. Because of the large number of digital information pieces involved, a few can easily be changed to convey secret messages without having a significant impact on the overall effect produced for the normal eye or ear. The secret information tends to be stored in the least important parts of a digital image or MP3 tune.

Consider the potential that steganography could have for terrorists trying to communicate with each other over the Internet. In a holiday e-picture, for example, dozens of pixels in the background could be altered to convey an airline’s schedule, and to some casual observer or to an FBI agent, the picture would likely appear to be “innocent” because the majority of the pixels would be left unchanged. However, anybody who was told where to look could access the information hidden in the amended pixels, which could then be put together and read.

Steganography involves a simple procedure that can be performed with software purchased from stores or downloaded from the Internet. The main reason for using steganography rather than cryptography is that anything encrypted tends to draw attention to the fact that some important information is deliberately being hidden.

See Also: Internet; Federal Bureau of Investigation (FBI).