The volume of communication occurring on the Internet now surpasses traditional media, such as letters or fax, and as a result, there is an urgent need to develop methods to secure online confidential communication. One method for confidential online communication is steganography. The term steganography is a combination of two Greek words, steganos, or “cover,” and graphein, or “writing.” Hence, steganography refers to “covered writing” or “secret writing.” It is categorized as a form of data hiding. It includes methods of secret communications using innocent-looking media in which the objective is to ensure that confidential information is communicated secretly without being detected by unauthorized third parties.

This entry proceeds in several steps. First, it provides an introduction to the field of steganography by describing its origins; ...