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News |
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2004-09-06
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Improved version of stegdetect released.
Stegdetect now supports linear discriminant analysis to detect any JPEG based
stego system. It also features improved detection of F5.
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2002-09-25
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Fridrich, Goljan and Hogea's "Attacking the OutGuess" is capable of reliably detecting
images with content embedded by OutGuess.
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2002-01-26
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Improved version of stegdetect released.
Stegdetect now detects data at the end of JPEG files hidden with tools
like appendX or camouflage.
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2001-12-21
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No hidden messages found in USENET analysis.
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2001-12-20
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Improved version of stegdetect released.
Accuracy for jsteg and jphide detection improved. Stegbreak now
uses the file magic utility to improve dictionary attack on outguess 0.13b.
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2001-10-12
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Steganography Trophy: First Steganographic Image found in the Wild.
Stegdetect and stegbreak were successful in
finding and retrieving a hidden message from an image.
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2001-08-31
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Higher-level statistical tests detect OutGuess 0.2.
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2001-04-14
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Initial release of stegdetect. It detects
hidden content in JPG images.
Currently detectable schemes are: jsteg, jphide and outguess 0.13b.
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What is OutGuess |
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OutGuess
is a universal steganographic tool that allows the insertion
of hidden information into the redundant bits of data sources. The
nature of the data source is irrelevant to the core of OutGuess. The
program relies on data specific handlers that will extract redundant
bits and write them back after modification. In this version the PNM
and JPEG image formats are supported. In the next paragraphs, images
will be used as concrete example of data objects, though OutGuess can
use any kind of data, as long as a handler is provided.
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How to get OutGuess |
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You can download OutGuess as UNIX source
tar ball. OutGuess is available under a BSD software license. It
is completely free for any use including commercial.
Please see each source file for its respective license. OutGuess was
developed in Germany.
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What is Steganography |
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Steganography is the art and science of hiding that communication is
happening. Classical steganography systems depend on keeping the
encoding system secret, but modern steganography is detectable only
if secret information is known, e.g. a secret key. Because of their
invasive nature, steganography systems leave detectable traces within a
medium's characteristics. This allows an eavesdropper to detect media
that has been modified, revealing that secret communication is taking
place. Although the secrecy of the information is not degraded, its
hidden nature is revealed, defeating the main purpose of
Steganography.
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What does OutGuess do differently |
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For JPEG images, OutGuess preserves statistics based on frequency
counts. As a result, statistical tests based on frequency counts are
unable to detect the
presence of steganographic content. Before embedding data into an
image, OutGuess can determine the maximum message size that can be
hidden while still being able to maintain statistics based on
frequency counts. This approach has been described in
OutGuess uses a generic iterator object to select which bits in the
data should be modified. A seed can be used to modify the behavior
of the iterator. It is embedded in the data along with the rest of the
message. By altering the seed, OutGuess tries to find a sequence of
bits that minimizes the number of changes in the data that have to be
made.
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(c) 1999-2004 by Niels Provos
OutGuess Resources
