Steganography is the practice of concealing information within another message or physical object in such a way that the presence of the hidden information is not apparent to an unsuspecting observer. The term comes from the Greek words steganos (covered or concealed) and graphia (writing), literally meaning “covered writing”.
Unlike cryptography, which focuses on making the content of a message unreadable to unauthorized parties, steganography aims to hide the very existence of the message itself. This means that, ideally, a steganographic message does not arouse suspicion, as it appears to be an ordinary, innocuous file or communication.
How Steganography Works
Steganography works by embedding secret data (the payload) into a non-secret file or message (the carrier), such as an image, audio, video, or text file. The hidden data is then extracted by someone who knows how and where to look for it.
A common digital method is the “least significant bit” (LSB) technique, where the secret information is embedded in the least significant bits of a media file, such as the color values of pixels in an image. These changes are subtle enough that they are not visually perceptible, making detection difficult without specialized tools.
Types of Steganography
There are several main types of steganography, including:
• Text steganography: Concealing information within text files, either by altering formatting, using specific patterns, or embedding data in the structure of the text.
• Image steganography: Hiding data within image files, often by modifying pixel values in a way that is imperceptible to the human eye.
• Audio steganography: Embedding secret messages in audio files by altering the binary sequence of the audio data.
• Video steganography: Concealing information within video files, which can use techniques similar to image and audio steganography but across multiple frames.
• Network steganography: Hiding data within network traffic, such as manipulating packet headers or timing of data transmissions.