Steganography, derived from Greek, literally means "covered writing." This art of hiding information includes a vast array of secret communication methods that conceal a message's very existence. Steganography and cryptography are cousins in the spycraft family: Steganography hides the message so that it cannot be seen. Cryptography scrambles a message so that it cannot be understood. Digital image steganography and its derivatives are growing in use and application. Where cryptography and strong encryption are outlawed, steganography can circumvent such policies to pass messages covertly. Commercial applications of steganography-digital watermarks and digital fingerprinting-are now being used to track the copyright and ownership of electronic media. Development in covert communications and steganography will continue, as will research in building more robust digital watermarks that can survive image manipulation and attacks. The more information that is made available on the Internet, the more owners of such information need to protect themselves from theft and false representation. In this article the authors discuss image files and how to hide information in them. To determine the limitations and flexibility of available software, they evaluated several steganographic packages. This article discusses three: Stego-Dos, White Noise Storm, and S-Tools for Windows.
