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