- How to Hide data (Steganography) into image file - OutGuess

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.

This process will allow us to store information of any kind within an image. This can be useful if you intend to send confidential information (such as a text document or a spreadsheet) to a person and do not want such information to be intercepted by someone else (such as the mail provider, a spy, police, etc. ..) We will use the technique of steganography to hide information within the image.

OutGuess Installation:
Ubuntu user can install OutGuess using Synaptic package manager or can install using command:
sudo apt-get install outguess

Data Embedding using OutGues:
Now here is how you do it: you need a text file (in this example we call it "hidden.txt" ) and a picture ( we call it "input.jpg" ) after that you issue the following command to hide your data ("hidden.txt") into the image file.

$ outguess -k "my_passwd" -d hidden.txt input.jpg out.jpg
Reading input.jpg....
JPEG compression quality set to 75
Extracting usable bits:   43283 bits
Correctable message size: 24627 bits, 56.90%
Encoded 'hidden.txt': 1128 bits, 141 bytes
Finding best embedding...
    0:   587(50.6%)[52.0%], bias    68(0.12), saved:    -2, total:  1.36%
   15:   550(47.4%)[48.8%], bias    73(0.13), saved:     1, total:  1.27%
   41:   585(50.4%)[51.9%], bias    32(0.05), saved:    -2, total:  1.35%
  198:   540(46.6%)[47.9%], bias    50(0.09), saved:     3, total:  1.25%
198, 590: Embedding data: 1128 in 43283
Bits embedded: 1160, changed: 540(46.6%)[47.9%], bias: 50, tot: 43059, skip: 41899
Foiling statistics: corrections: 174, failed: 187, offset: 158.255556 +- 316.069419
Total bits changed: 590 (change 540 + bias 50)
Storing bitmap into data...
Writing out.jpg....
$

Data Retrieval
You can retrieve data from an image in the following way:
$ outguess -k "my_passwd" -r out.jpg hidden.txt
Reading out.jpg....
Extracting usable bits:   43283 bits
Steg retrieve: seed: 198, len: 141



source:http://linuxpoison.blogspot.com/2010/08/135781677514136.html