A self-contained, independent entity of data carrying sufficient information to be routed from the source to the destination computer without reliance on earlier exchanges between this source and destination computer and the transporting network. The term has been generally replaced by the term packet.

Dead drop

A method of secret information exchange where the two parties never meet.


A company that creates digital watermarking technology used to authenticate, validate, and communicate information within digital and analog media.

Digital Rights Management (DRM)

Focuses on security and encryption to prevent unauthorized copying, limiting distribution to only those who pay. This is considered first-generation DRM; second-generation DRM covers description, identification, trading, protection, monitoring, and tracking of all forms of rights usages over both tangible and intangible assets, including management of rights holders' relationships. It is important to note that DRM manages all rights, not only those involving digital content. Additionally, it is important to note that DRM is the "digital management of rights" and not the "management of digital rights." That is, DRM manages all rights, not only the rights applicable to permissions over digital content.

Discrete cosine transform (DCT)

Used in JPEG compression, the discrete cosine transform helps separate the image into parts of differing importance based on the image's visual quality; this allows for large compression ratios. The DCT function transforms data from a spatial domain to a frequency domain.


An undesired change in an image or signal; a change in the shape of an image resulting from imperfections in an optical system, such as a lens.


Creating the illusion of new colors and shades by varying the pattern of dots in an image. Dithering is also the process of converting an image with a certain bit depth to one with a lower bit depth.

Echo hiding

Relies on limitations in the human auditory system by embedding data in a cover audio signal using changes in delay and relative amplitude. Two types of echos are created, which allows for the encoding of 1s and 0s.

Embedded message

In steganography, it is the hidden message that is to be put into the cover-medium.


To cause to be an integral part of a surrounding whole. In steganography and watermarking, refers to the process of inserting the hidden message into the cover-medium.


Floppy Disk Drive.


A form of marking that embeds a unique serial number.

File format dependence

A factor in determining the robustness of a piece of stegoed media. Coverting an image from one format to another will usually render the embedded message unrecoverable.

Fourier transform

An image processing tool that is used to decompose an image into its constituent parts or to view a signal in either the time or frequency domain.

Fragile watermark

A watermark that is designed to prove authenticity of an image or other media. A fragile watermark is destroyed, by design, when the cover is manipulated digitially. If the watermark is still intact, then the cover has not been tampered with. Fragile watermark technology could be useful in authenticating evidence or ensuring the accuracy of medical records or other sensitive data.

Frequency domain

The way of representing a signal where the horizontal deflection is the frequency variable and the vertical deflection is the signal's amplitude at that frequency.

Frequency masking

A condition where two tones with relatively close frequencies are played at the same time and the louder tone masks the quieter tone.

Hidden partition

A method of hiding information on a hard drive where the partition is considered unformatted by the host operating system and no drive letter is assigned.


Using this method, a secret message is put in a host file in such a way that when the file is actually read by a given program, the program ignores the data.

Intellectual property identification

A method of asset protection that identifies or defines a copyright, patent, trade secret, etc., or validates ownership and ensures that intellectual property rights are protected.

Intellectual property management and protection (IPMP)

A refinement of digital rights management (DRM) that refers specifically to MPEGs.


A company that develops intellectual property for digital rights management (DRM), digital policy management (DPM), and trusted computing systems.

Invisible ink

A method of steganography using a special ink that is colorless and invisible until treated by a chemical, heat, or special light. It is sometimes referred to as sympathetic ink.

Invisible watermark

An overlaid image that is invisible to the naked eye, but which can be detected algorithmically. There are two different types of invisible watermarks: fragile and robust.

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

Similar book on Amazon

flylib.com © 2008-2017.
If you may any questions please contact us: flylib@qtcs.net