DATA HIDING TECHNIQUE USING ENTROPY CALCULATION AND IMAGE
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Transcript of DATA HIDING TECHNIQUE USING ENTROPY CALCULATION AND IMAGE
DATA HIDING TECHNIQUE USING ENTROPY CALCULATION AND IMAGE COMPRESSION
USING BTC
BYSHASHIVARDHAN N.A
1ST SEM M.TechD.E.C.S
OVERVIEWINTRODUCTION
STEPS INVOLVED
BLOCK TRUNCATION CODING
EMBEDDING ALGORITHM
EXTRACTION ALGORITHM
APPLICATIONS
CONCLUSION
BIBLIOGRAPHY
DATA HIDING TECHNIQUE USING ENTROPY CALCULATION AND IMAGE COMPRESSION USING BTC
OBJECTIVE:
To provide a secure data hiding technique using information theory and also generate random distribution of message image over the cover image and also compress the message using block truncation coding and recover it at high quality.
DATA HIDING TECHNIQUE USING ENTROPY CALCULATION AND IMAGE COMPRESSION USING BTC
STEPS INVOLVED…………
Message image compression using block truncation coding (BTC)
Embedding the message image into the cover image.
Extracting message image from cover image.
DATA HIDING TECHNIQUE USING ENTROPY CALCULATION AND IMAGE COMPRESSION USING BTC
COVER IMAGE EMBEDDING
KEY
STEGO IMAGE
MESSAGE
MESSAGE EXTRACTING
KEY
DATA HIDING TECHNIQUE USING ENTROPY CALCULATION AND IMAGE COMPRESSION USING BTC
The block truncation coding involves the following steps: An image is divided into non-overlapping blocks. The size of a block
could be (4 × 4) or (8 × 8) , etc (here we will use (4 × 4) blocks). Calculate the average gray level of the block. For (4 × 4) block:
m =1/16 ΣΣx(i,j) , x (i, j) represents pixels in the block.
Pixels in the image block is then classified into two kinds first: with their gray level is greater than block average gray level and
Second: with their gray level is lower than or equal block average gray level. The average gray level of this two kind of pixels are calculated:
Where K is the number of pixels whose gray level is greater than m.
DATA HIDING TECHNIQUE USING ENTROPY CALCULATION AND IMAGE COMPRESSION USING BTC
BTC CONTD……
A binary block, denoted b, is also needed to classify the pixels. We can use “1” to represent a pixel whose gray level is greater than m and “0” to represent a pixel whose gray level is less than or equal to m.
In the encoder an image block is constructed by replacing with “1’s” and with “0’s”.
DATA HIDING TECHNIQUE USING ENTROPY CALCULATION AND IMAGE COMPRESSION USING BTC
BTC CONTD……
THE ORIGINAL IMAGE BLOCK. THE ENCODED BINARY BLOCK
THE AVERAGE GRAY LEVEL=159
THE RECONSTRUCTED IMAGE
BLOCK BY THE DECODER
DATA HIDING TECHNIQUE USING ENTROPY CALCULATION AND IMAGE COMPRESSION USING BTC
EMBEDDING ALGORITHM:
“ This algorithm takes cover, message images and a key as an input and produces a stego image”.
Cover image
Hiding system
Secret image
Secret key
Stego image
EMBEDDING ALGORITHM
.
DATA HIDING TECHNIQUE USING ENTROPY CALCULATION AND IMAGE COMPRESSION USING BTC
DATA HIDING TECHNIQUE USING ENTROPY CALCULATION AND IMAGE COMPRESSION USING BTC
MSB LSB
8 7 6 5 4 3 2 1
LSB: Least significant bit
8 bits/pixelExample:
1 0 0 0 0 0 0 0 =128
1 0 0 0 0 1 1 1 =135
Original pixel value
Processed pixel value
Similar
color
BLOCK DIAGRAM
Secret image
Hiding system
Cover image
Cover image
Stego image
Secret key
extraction
DATA HIDING TECHNIQUE USING ENTROPY CALCULATION AND IMAGE COMPRESSION USING BTC
EXTRACTION: The extraction algorithm reverse the operation of
embedding algorithm, using key and entropy calculation to determine the amount of data embedded in each pixel and recover it to construct the message again from cover.
First divide the stego-image into blocks and do the following: calculate the entropy of the’4’ most significant bits. If it is
greater than ‘2’ then recover ‘4’ bits from 4 least significant bits if not calculate the entropy of ‘5’ most significant bits if it is greater than’2’ then recover ‘3’ bits from ‘3’ least significant bits if not then recover ‘2’ bits from ‘2’ least significant bits.
After recovering the different bits decode it again by using the BTC algorithm and reconstruct the message image.
DATA HIDING TECHNIQUE USING ENTROPY CALCULATION AND IMAGE COMPRESSION USING BTC
APPLICATIONS:
SECRET COMMUNICATION:- in military issues, trade secret ,blue print or other sensitive information can be transmitted without alerting the hackers.
COPYRIGHT PROTECTION:- A secret copyright notice or watermark can be embedded inside an image to identify it as intellectual property. In addition ,when an image is sold or distributed an identification of the recipient and time stamp can be embedded to identify potential pirates.
DATA HIDING TECHNIQUE USING ENTROPY CALCULATION AND IMAGE COMPRESSION USING BTC
CONCLUSION AND SCOPE FOR FUTURE WORK:-
This paper provides a secure data hiding technique using information theory and also generate random distribution of message image over the cover image and also compress the message using block truncation coding and recover it at high quality.It also provides large data embedding without making noticeable distortion.
FUTURE WORK:-Hiding not only images but extending it to audio, text formats, etc.
REFERENCES
Secure Perceptual Data Hiding Technique using Information Theory, Mohiy M. Hadhoud, Nabil A. Ismail, Shawky El-kelany, ICEEC’04, Faculty of Engineering- Ain Shams University, Cairo, Egypt, September 2004.
An Entropy Based Technology for Information Embedding In Images, Marc Van Droogenbroeck and Jerome Delvaux , Institute Montefiore B-28 , Department of Electrical and Computer Science.
Information Hiding – A Survey ,Febien A. P. ,Ross Anderson and Markus G. Kuhn, Proceeding of the IEEE, special issue on protection of multimedia content,87(7):1062 - 1078,july 1999.
Applications for Data Hiding , W. Bender , W. Butera , D. Gruhi , R. Hwang , F. J. Paiz , S. Pogreb , IBM System Journal , VOL 39 ,NOS 3&4 ,2000.