This version of the Independent JPEG Group's JPEG Software (release 4)
has been modifed for 1-bit steganography in JFIF output files.

Steganography is the science of hiding data in otherwise plain text or
images.  Here, we are hiding the data inside images stored in the JFIF
format of the JPEG standard.  It was believed that this type of
steganography was impossible, or at least infeasible, since the JPEG
standard uses lossy encoding to compress its data.  Any hidden data
would be overwhelmed by the noise.  The trick used by this
steganographic implementation is to recognize that JPEG encoding is
split into lossy and non-lossy stages.  The lossy stages use a
discrete cosine transform and a quantization step to compress the
image data; the non-lossy stage then uses Huffmann coding to further
compress the image data.  As such, we can insert the steganographic
data into the image data between those two steps and not risk
corruption.

 PERMSSN    UID  GID    PACKED    SIZE  RATIO     CRC       STAMP          NAME
---------- ----------- ------- ------- ------ ---------- ------------ -------------
[generic]                28194   56996  49.5% -lh5- b815 Apr  6  1996 bin/cjpeg.jsteg
[generic]                27250   52256  52.1% -lh5- 86bf Apr  6  1996 bin/cjpeg.jsteg.020
[generic]                29445   58056  50.7% -lh5- 283f Apr  6  1996 bin/djpeg.jsteg
[generic]                28108   53408  52.6% -lh5- b1cb Apr  6  1996 bin/djpeg.jsteg.020
[generic]                 6381   12396  51.5% -lh5- 1950 Apr  6  1996 doc/cjpeg.dvi
[generic]                 3898   10152  38.4% -lh5- 6259 Apr  6  1996 doc/cjpeg.man
[generic]                 3826    7260  52.7% -lh5- 53a1 Apr  6  1996 doc/djpeg.dvi
[generic]                 2270    5957  38.1% -lh5- 0bc8 Apr  6  1996 doc/djpeg.man
[generic]                 9039   21128  42.8% -lh5- 93e9 Apr  6  1996 doc/README
[generic]                 1639    3539  46.3% -lh5- d1eb Apr 21  1996 doc/README.AMIGA
[generic]                 2514    5760  43.6% -lh5- 355c Apr  6  1996 doc/README.jsteg
[generic]                 5934   14687  40.4% -lh5- 98c1 Apr  6  1996 doc/USAGE
---------- ----------- ------- ------- ------ ---------- ------------ -------------
 Total        12 files  148498  301595  49.2%            Apr 27  1996