Iteration 2 Progress Report

William Barratt

Plan:

  Goal: Develop a basic method for steganography using .pgm image files 
in C++, building on the header-reading code from Iteration 1.

  Needs: a good algorithm, reference database of C library info

  Expected Outcome: a command-line program to insert a text message into a 
.pgm file

  Success Test: checking the modification of the file; Iteration 3 will be 
the final check for this iteration when it successfully decodes the image 
from the file.

  Timeline: completion of Iteration 2 by early November.

Design:
  Use approach from ComputerWorld.com article (picture can be found at http://www.tjhsst.edu/~wbarratt/techlab/stegano1.jpeg).
  
Coding:
  Used stdio functions for file operations.  Used bitwise operators to do steganographic modifications.

Testing:
  Extraction program works!  I also added the capability to specify filenames from the command line, to make things more user-friendly.  This iteration is finished.

Links to code:
Steganography program
Extraction program

Screenshots:
Screenshot of program running in terminal
Original image file (converted to JPEG)
Image file with message included (converted to JPEG)
Note the lack of perceptible difference between the original and the message file image.

Updated Nov. 20, 2002