Steganography is the art of covered, or hidden, writing. The purpose of steganography is covert communication to hide a message from a third party. This differs from cryptography, the art of secret writing, which is intended to make a message unreadable by a third party but does not hide the very existence of the secret communication. Although the term steganography was only coined at the very end of the fifteenth century, the use of stego dates back several millennia. Steganography hides the covert message but not the fact that two parties are communicating with each other.
The stego process generally involves placing a hidden message within some transport medium, called the carrier. The secret message is embedded within the carrier to form the stego medium. The use of a stego key may be employed for encryption of the hidden message and/or for randomization within the stego scheme. As an increasing amount of data is stored on computers and transmitted over networks, it is no surprise that steganography has entered the digital age.
