SliTaz Repositories

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     1.4 +Outguess is a universal steganographic tool that allows
     1.5 +the insertion of hidden information into the redundant
     1.6 +bits of data sources.
     1.7 +The nature of the data source is irrelevant to the core
     1.8 +of outguess. The program relies on data specific handlers
     1.9 +that will extract redundant bits and write them back
    1.10 +after modification.
    1.11 +Currently only the PPM (Portable Pixel Map), PNM
    1.12 +(Portable Any Map), and JPEG image formats are supported,
    1.13 +although outguess could use any kind of data, as long as
    1.14 +a handler were provided.
    1.15 +
    1.16 +Steganography is the art and science of hiding that
    1.17 +communication is happening.
    1.18 +Classical steganography systems depend on keeping the
    1.19 +encoding system secret, but modern steganography are
    1.20 +detectable only if secret information is known, e.g. a
    1.21 +secret key.
    1.22 +Because of their invasive nature steganography systems
    1.23 +leave detectable traces within a medium's characteristics.
    1.24 +This allows an eavesdropper to detect media that has been
    1.25 +modified, revealing that secret communication is taking
    1.26 +place. Although the secrecy of the information is not
    1.27 +degraded, its hidden nature is revealed, defeating the
    1.28 +main purpose of Steganography.
    1.29 +
    1.30 +For JPEG images, OutGuess preserves statistics based on
    1.31 +frequency counts.
    1.32 +As a result, no known statistical test is able to detect
    1.33 +the presence of steganographic content.
    1.34 +Before embedding data into an image, the OutGuess system
    1.35 +can determine the maximum message size that can be hidden
    1.36 +while still being able to maintain statistics based on
    1.37 +frequency counts.
    1.38 +
    1.39 +OutGuess uses a generic iterator object to select which
    1.40 +bits in the data should be modified.
    1.41 +A seed can be used to modify the behavior of the iterator.
    1.42 +It is embedded in the data along with the rest of the
    1.43 +message. By altering the seed, OutGuess tries to find a
    1.44 +sequence of bits that minimizes the number of changes in
    1.45 +the data that have to be made.