DragonFly On-Line Manual Pages

STEGDETECT(1)          DragonFly General Commands Manual         STEGDETECT(1)

NAME
     stegdetect - finds image files with steganographic content

SYNOPSIS
     stegdetect [-qhnV] [-s float] [-C num,tfname] [-c file ... name]
                [-D file] [-d num] [-t tests] [file ...]

DESCRIPTION
     The stegdetect utility analyses image files for steganographic content.
     It runs statistical tests to determine if steganographic content is
     present, and also tries to find the system that has been used to embed
     the hidden information.

     The options are as follows:

     -q        Only reports images that are likely to have steganographic
               content.

     -h        Only calculates the DCT histogram.  Use the -d option to
               display the values.

     -n        Enables checking of JPEG header information to surpress false
               positives.  If enabled, all JPEG images that contain comment
               fields will be treated as negatives.  OutGuess checking will be
               disabled if the JFIF marker does not match version 1.1.

     -V        Displays the version number of the software.

     -s float  Changes the sensitivity of the detection algorithms.  Their
               results are multiplied by the specified number.  The higher the
               number the more sensitive the test will become.  The default is
               1.

     -C num,tfname
               Feature vectors are being extraced from the images.  The
               argument num can either be zero or one.  A zero indicates that
               the provided images do not contain steganographic content, a
               one indicates that they do.  The argument tfname is the name of
               transform used for feature extraction.  The features vectores
               are printed to stdout.

     -c file   Reads the data created by the -C options and computes the
               necessary values to detect steganographic content in yet
               unknown images.  The option can be used multiple times.  It
               expects that the name of the scheme provided as additional
               argument.  The result is a decision object that can be used
               with the -D option.  The decision object contains a the
               parameters for a linear discriminant function based on the
               Neyman-Pearson theorem.

     -D file   Reads a decision object that contains detection information
               about a new steganographic scheme.

     -d num    Prints debug information.

     -t tests  Sets the tests that are being run on the image.  The following
               characters are understood:

               j       Tests if information has been embedded with jsteg.

               o       Tests if information has been embedded with outguess.

               p       Tests if information has been embedded with jphide.

               i       Tests if information has been hidden with invisible
                       secrets.

               f       Tests if information has been hidden with F5.

               F       Tests if information has been hidden with F5 using a
                       more sophisticated but fairly slow detection algorithm.

               a       Tests if information has been added at the end of file,
                       for example by camouflage or appendX.

               The default value is jopifa.

     The stegdetect utility indicates the accuracy of the detection with a
     number of stars behind the detected system.  If no filenames have been
     specified, stegdetect will read the filenames from stdin.

EXAMPLES
     stegdetect -t p auto.jpg

     Tries to detect the presence of jphide embedded information in auto.jpg.

ERRORS
     stegdetect works only for JPEG images.

     Currently, there is no support for parameter training.  The only exported
     knob is the sensitivity level.  Future versions will export all detection
     parameters via a configuration file.

SEE ALSO
     stegbreak(1)

ACKNOWLEDGEMENTS
     This product includes software developed by Ian F. Darwin and others.
     The stegdetect utility uses Darwin's file magic to identify data appended
     at the end of an image.

AUTHORS
     The stegdetect utility has been developed by Niels Provos.

DragonFly 6.5-DEVELOPMENT        April 1, 2001       DragonFly 6.5-DEVELOPMENT