- "Steganography is the practice of representing information within another message or physical object, in such a manner that the presence of the information is not evident to human inspection."
The study of techniques used to hide data within other data.
Introduction to Steganography: An overview of what Steganography is and its history.
Steganography Techniques: Various methods used to hide information within an image, audio or video files.
Steganography Tools: A list of software used to implement the techniques for data hiding.
Information Theory: Basic concepts of Information theory that underlie steganography.
Digital Signal Processing: Signal processing concepts such as discrete Fourier transform, filtering, and compression that are relevant for Steganography.
Cryptography: An understanding of Cryptology, which includes Cryptography and Cryptanalysis, is important to understand the security aspect of Steganography.
Embedding Capacity: Find out the amount of information that can be embedded into an image, audio or video file.
Channel Capacity: The maximum amount of information that can be transmitted, usually measured in bits per second (bps).
Steganalysis: Techniques used to detect the presence of hidden messages in a file.
Host File Removal: The steps involved in removing a hidden message that was inserted in a host file.
Covert Channels: Concealing communication within a file or system that is not intended for that purpose.
Watermarking: The process of embedding an unobtrusive mark or logo within a media file to protect the integrity of the contents.
Digital Forensics: An area of digital investigation interested in reconstructing corruption or information theft.
Encoding and Decoding: The process of translating information from one format into another format, such as ASCII to binary.
Hashing Algorithms: Creating unique, fixed-size easy-to-identify outputs from data that can be used for indexing, data verification or authentication.
LSB Steganography: Least Significant Bit (LSB) Steganography encodes hidden message within the least significant bits of an image's pixels. It is one of the simplest techniques of steganography and requires the modification of only one or two bits per pixel.
Masking Steganography: Masking Steganography involves hiding a secret message within an image by modifying the color values of the pixels that belong to the message. The secret message is usually encrypted, and then the least significant bits are swapped with the pixel values.
Audio Steganography: Audio Steganography uses sound files to hide secret messages within the sound waves, often by modifying certain features of the sound file that the human ear cannot detect. This could involve shifting the frequencies slightly or subtly changing the phase of the sound.
Video Steganography: Video Steganography hides secret messages within video files by slightly modifying the frames of the video, either by altering the color or brightness of individual pixels, or by subtly shifting entire frames to encode the hidden message.
Text Steganography: Text Steganography involves hiding a secret message within a larger body of text. Some common techniques for this include letter substitution, punctuation modification and whitespace manipulation.
Steganographic File Systems: Steganographic File Systems involve embedding secret data within unused portions of a file system. This means that hidden data can be spread across multiple files or file system components, making it difficult to detect or uncover.
Network Steganography: Network Steganography is used to hide data within network protocols, such as TCP/IP packets, DNS requests or HTTP headers. This can make it more difficult to detect or monitor network traffic for unauthorized activity.
Spatial Domain Steganography: Spatial Domain Steganography involves directly modifying the visual information of an image to hide a secret message within it.
Frequency Domain Steganography: Frequency Domain Steganography involves encoding the secret message within an image in a way that exploits the Fourier transform of the image. It can be used to hide encrypted messages within the image without altering the appearance of the image itself.
Linguistic Steganography: Linguistic Steganography hides secret messages within natural language texts by using complex algorithms that are based on characteristics of the text that can be manipulated. This steganography technique can be very challenging to detect, as the changes made to the text are often very subtle.
Printed Circuit Board (PCB) Steganography: PCB Steganography uses small, hidden modifications to electronic circuits in order to hide messages or data. It is most commonly used to hide data in industrial control systems, medical devices, or other types of equipment that use electronic circuits.
DNA Steganography: DNA Steganography uses the four nucleotide "letters" of DNA to encode hidden messages. This can be done by altering the order of nucleotide bases in a strand of DNA or by inserting patterns of nucleotides that correspond to specific messages.
Time Domain Steganography: Time domain steganography encodes hidden messages within temporal signals, such as audio or video files, by manipulating the timing or duration of signals in a very precise manner. This technique can be hard to detect because it does not require changes to the actual data within a signal.
- "The word steganography comes from Greek steganographia, which combines the words steganós (στεγανός), meaning 'covered or concealed', and -graphia (γραφή) meaning 'writing'."
- "The first recorded use of the term was in 1499 by Johannes Trithemius in his Steganographia, a treatise on cryptography and steganography, disguised as a book on magic."
- "Generally, the hidden messages appear to be (or to be part of) something else: images, articles, shopping lists, or some other cover text."
- "The advantage of steganography over cryptography alone is that the intended secret message does not attract attention to itself as an object of scrutiny."
- "Some implementations of steganography that lack a formal shared secret are forms of security through obscurity, while key-dependent steganographic schemes try to adhere to Kerckhoffs's principle."
- "Media files are ideal for steganographic transmission because of their large size."
- "For example, a sender might start with an innocuous image file and adjust the color of every hundredth pixel to correspond to a letter in the alphabet."
- "The change is so subtle that someone who is not specifically looking for it is unlikely to notice the change."
- "In computing/electronic contexts, a computer file, message, image, or video is concealed within another file, message, image, or video."
- "Plainly visible encrypted messages, no matter how unbreakable they are, arouse interest and may in themselves be incriminating in countries in which encryption is illegal."
- "Whereas cryptography is the practice of protecting the contents of a message alone, steganography is concerned with concealing both the fact that a secret message is being sent and its contents."
- "In digital steganography, electronic communications may include steganographic coding inside of a transport layer, such as a document file, image file, program, or protocol."
- "Media files are ideal for steganographic transmission because of their large size."
- "The change is so subtle that someone who is not specifically looking for it is unlikely to notice the change."
- "The hidden messages appear to be (or to be part of) something else."
- "Some implementations of steganography that lack a formal shared secret are forms of security through obscurity, while key-dependent steganographic schemes try to adhere to Kerckhoffs's principle."
- "Whereas cryptography is the practice of protecting the contents of a message alone, steganography is concerned with concealing both the fact that a secret message is being sent and its contents."
- "For example, the hidden message may be in invisible ink between the visible lines of a private letter."
- "The intended secret message does not attract attention to itself as an object of scrutiny."