-------------------------------------------------------------------------------
Stenography - Hiding files in other files (such as images)

This is generally hiding information so that it appears to be something else.
If it can be hidden perfectly (not typical the case when hiding say images in
some other other images) then you can also encrypt the data as a exta level of
security.

See   http://en.wikipedia.org/wiki/Steganography

===============================================================================
Image message hiding (or in video)

Commercial
  http://mozaiq.org/encrypt/
Basied on
  Genetic Algorithm based Mosaic Image Steganography for Enhanced Security
  https://www.slideshare.net/ideseditor/17-30793821

Opensource Project
  https://github.com/dyne/Tomb/wiki/Advancedfeatures

OpenPuff
  http://download.cnet.com/OpenPuff/3000-2092_4-75450743.html


-------------------------------------------------------------------------------
RAR/Zip files in PNG images

RAR files can be added to end of a PNG file, and will still decode!
PNG itself is a well defined image format with well defined end data marker.

Hide by appending to a PNG file.
   rar a archive.rar file
   cat archive.rar >> picture.png

Extract
   unrar x picture.png

or extract specific file
   unrar p -inul picture.png file

For zip files use 7Zip to extract

Best to make sure picture around the same size or larger, compared to the RAR

-------------------------------------------------------------------------------