T-P


O-S

Oblivious scheme

See Blind scheme.

One-time pad

A system that randomly generates a private key, and is used only once to encrypt a message that is then decrypted by the receiver using a matching one-time pad and key. One-time pads have the advantage that there is theoretically no way to "break the code" by analyzing a succession of messages.

Open code

A form of hidden communication that uses an unencrypted message. Jargon code is an example of open code.

OpenMG

A copyright protection technology from Sony that allows recording and playback of digital music data on a personal computer and other supported devices, but prevents unauthorized distribution.

Packet

See Datagram.

Patchwork

An encoding algorithm that takes random pairs of pixels and brightens the brighter pixel and dulls the duller pixel and encodes one bit of information in the contrast change. This algorithm creates a unique change, and that change indicates the absence or presence of a signature.

Payload

The amount of information that can be stored in the cover medium. Typically, the greater the payload, the greater the risk of detection.

PCM(Pulse Code Modulation)

Is a digital scheme for transmitting analog data.

Perceptual masking

A condition where the perception of one element interferes with the perception of another.

PictureMarc

A DigiMarc application that embeds an imperceptible digital watermark within an image, allowing copyright communication, author recognition, and electronic commerce. It is currently bundled with Adobe Photoshop.

Piracy (or simple piracy)

The unauthorized duplication of an original recording for commercial gain without the consent of the rightful owner; the packaging of pirate copies that is different from the original. Pirate copies are often compilations, such as the "greatest hits" of a specific artist, or a genre collection, such as dance tracks.

Pixel

Short for Picture Element, a pixel is a single point in a graphic image. It is the smallest thing that can be drawn on a computer screen. All computer graphics are made up of a grid of pixels. When these pixels are painted onto the screen, they form an image.

Raster image

An image that is composed of small points of color data called pixels. Raster images allow the representation of complex shapes and colors in a relatively small file format. Photographs are represented using raster images.

RGB(Red, Green, Blue)

Refers to a system for representing the colors to be used on a computer display.

Recording Industry Association of America (RIAA)

A trade group that represents the recording industry in the United States. The RIAA works to create a business and legal environment that supports the record industry and seeks to protect intellectual property rights.

Robust watermark

A watermark that is very resistant to destruction under any image manipulation. This is useful in verifying ownership of an image suspected of misappropriation. Digital detection of the watermark indicates the source of the image.

Secure Digital Music Initiative (SDMI)

A forum of more than 160 companies and organizations representing a broad spectrum of information technology and consumer electronics businesses, Internet service providers, security technology companies, and members of the worldwide recording industry working to develop voluntary, open standards for digital music. SDMI is helping to enable the widespread Internet distribution of music by adopting a framework that artists and recording and technology companies can use to develop new business models.

Semagram

Semantic symbol. Semagrams are associated with a concept and do not use writing to hide a message.

Slack space

The unused space in a group of disk sectors; the difference in empty bytes of the space that is allocated in clusters minus the actual size of the data files.

Spatial domain

The image plane itself; the collection of pixels that composes an image.

Spread-spectrum image steganography

A method of steganographic communication that uses digital imagery as the cover signal.

Spread-spectrum techniques

The method of hiding a small or narrow-band signal (message) in a large or wideband cover.

Steganalysis

The art of detecting and neutralizing steganographic messages.

Steganalyst

One who applies steganalysis with the intent of discovering hidden information.

Steganographic file system

A method of storing files in a way that encrypts data and hides it such that it cannot be proven to exist.

Steganography

The method(s) of concealing the existence of a message or data within seemingly innocent covers.

Stego-only attack

An attack where only the stego-object is available for analysis.

Stegokey

A key that allows extraction of the secret information out of the cover.

Stego-medium

The resulting combination of a cover-medium and embedded message and a stego key.

StirMark

A method of testing the robustness of a watermark. StirMark is based on the premise that many watermarks can survive a simple manipulation to the file, but not a combination of manipulations. It simulates a process similar to what would happen if an image was printed and then scanned back into the computer by stretching, shearing, shifting, and rotating an image by a tiny random amount.

Substitution

The steganographic method of encoding information by replacing insignificant bits from the cover with the bits from the embedded message.

Supraliminal channel

A feature of an image that is impossible to remove without gross modifications, i.e., a visible watermark.




Investigator's Guide to Steganography
Investigators Guide to Steganography
ISBN: 0849324335
EAN: 2147483647
Year: 2003
Pages: 220

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