Basic Model Of Steganography
Requirements that must be satisfied
Steganography is of Greek origin where Greek words
steganos meaning "covered or protected"
graphei meaning "writing "
Hence steganography means concealed writing .
Steganography is the art and science of embedding secret messages in cover
message in such a way that no one, apart from the sender and intended
recipient, suspects the existence of the message.
Tattooing message on
Writing messages on wood underlying
PERSHING SAILS FROM NY JUNE 1
Use of invisible inks
Use of null ciphers
SECRET MESSAGE is the information to be hidden in suitable media.
COVER MESSAGE is the carrier of secret information such as image, audio,
EMBEDDING ALGORITHM is the way or the idea that usually used to embed
the secret information in the cover message.
STEGO OBJECT is the cover message with secret message hidden in it .
Inputs of Embedding Algorithm
Inputs of Extraction Algorithm
In this method instead of hiding data in LSB of RGB components, data is hidden
as shown in following example:
Let the data to be hidden is word 'ABC'.
Find the ASCII code of every character to be hidden.
ASCII code of A is 65 and its corresponding binary is 01000001
ASCII code of B is 66 and its corresponding binary is 01000010
ASCII code of C is 67 and its corresponding binary is 01000011
Let the RGB component of first pixel:
Red component is replaced by ASCII code of A in binary i.e. 01000001 :
Green component of second pixel is replaced by ASCII code of B
Blue Component of third pixel is replaced by ASCII code of C
Inputs: - Text file, cover image 1, cover image 2 and secret key.
Output: - Stego image.
1. Select text file,
convert into binary and calculate number of bits
2. Select cover image 1 for hiding purpose
find the number of pixels,
split it into RGB components
3. If bits are compatible with the image resolution, then
start sub iteration 1, else
start sub iteration 2
4. Provide security key
5. Select cover image 2 to hide distorted stego image
SUB ITERATION 1
Replace red component of the first pixel with first character
Replace green component of the second pixel with second character.
Replace blue component of the third pixel with third character
And repeat iterations until pixels get exhaust
Stop sub iteration 1
SUB ITERATION 2
Replace necessary bits as in immediate component of each pixel
Store the information about bits embedded in a binary address file
And repeat iterations until pixels get exhaust
Stop sub iteration2
binary & cal.
no. of bits
If no. of bits=Resolution
of pixels in
If no. of bits ≠ Resolution
Replace red comp.
of 1st pixel with 1st
necessary bits in
comp. of 2nd pixel
with 2nd character
Store info. about
bits embedded in
comp. of 3rd pixel
with 3rd character
Cover Image 1
Input: - Stego image and secret key.
Output: - Secret text file.
1. Browse the stego image.
2. Choose the folder in which you want to extract the hidden text file.
3. Provide necessary security key.
4. Convert the binary file into human readable form.
Human Visual System (HVS) –
Insensitivity to gradual changes in shade
Insensitive to high frequencies and blue region of visible spectrum
Human Audio System (HAS) –
Sensitive to additive random noise
Inability to perceive absolute phase
The following is a list of main requirements that steganography techniques
must satisfy :
The integrity of the hidden information after it has been embedded inside
the stego object must be correct.
The stego object must remain unchanged or almost unchanged to the
In watermarking, changes in the stego object must have no effect on the
Finally, we always assume that the attacker knows that there is hidden
information inside the stego object.
Used by intelligence agencies.
Used by military forces to send secret messages.
Used in modern printers.
Used in digital watermarking.
Used by terrorists.
Used for corporate espionage to send out trade secrets.
Rotation and Scaling
Depending on these types of attacks steganography may
be classified as robust or fragile .
 Vipul Sharma, Sunny Kumar, “ A New Approach to Hide Text in Images
Using Steganography”, IJARCSSE, Volume 3, Issue 4, ISSN: 2277
128X, April 2013.
 James C. Judge, “Steganography: Past, Present, Future”, SANS Institute
 Ross J. Anderson, Fabien A.P. Petitcolas, “On The Limits of
Communications, 16(4):474-481, ISSN 0733-8716, May 1998.
 Ananthi S, Anjanadevi A “Reversible Image Data Hiding Using Predictive
Coding Technique Based on Steganograpic Scheme”, IOSR Journal of
Engineering (IOSRJEN) ISSN: 2250-3021 Volume 2, Issue 7(July 2012).
 Shashikala Channalli, Ajay Jadhav, “Steganography An Art of Hiding
Data”, International Journal on Computer Science and Engineering Vol.1(3),
 Emad T. Khalaf, Norrozila Sulaiman,"A Robust Data Hiding Technique
based on LSB Matching", World Academy of Science, Engineering and
Technology 58, 2011.
 Atallah M. Al-Shatnawi, "A New Method in Image Steganography with
Improved Image Quality",Applied Mathematical Sciences, Vol. 6, 2012.