Steganography is a branch of security science that involves concealing a communication within another communication or file. This type of security technique is used to disguise sensitive data or communications in an innocuous form. For example, one could hide a set of secret numbers behind an image file. This type of technique was used by spies during World War II to conceal messages.
Steganography is related to cryptography as it also utilizes a cipher to convert a message into an encoded file or document. However, while cryptography focuses on making an encoded message unintelligible, steganography focuses on hiding the very existence of an encoded message. It does this by hiding it behind another form of data, such as an image, sound or text file. Modern steganography can also be used to prevent digital watermarking, a technique which identifies who created an electronic document, song or video.
Steganographic techniques most commonly employ algorithms, software and hardware that are applied and used to hide secret data in existing files. By manipulating pixel values in an image, for instance, a user could hide text data inside the image. To the human eye, the image would appear to look the same, but the data inside would be concealed.
Another modern form of steganography is called digital signatures. A digital signature is a method that can be used to authenticate a digital document. This is done by encoding the signature of the sender into the digital document itself, using steganography and cryptography.
Traditional methods of steganography were used for centuries by spies and diplomats alike to protect the secrets found on documents from curious eyes. Today, steganography is often used by individuals or companies seeking to protect sensitive data files from being hacked or stolen. It is also used to detect digital watermarking as well as to authenticate digital documents.
