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Air University
A REVIEW ON
STEGANOGRAPHY USING
TRIGNOMETRIC CHAOTIC MAP
Umair Habib
Department of Mathematics
Air University
2021.07. 29
Supervised By
Dr. Mahwish Bano

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Table of Contents
Steganography
1
Object ives of
St eganography
2
Forms of
steganography:
3 Text
4
Audio
5 Video
6
Image
7 List of chaot ic maps
8

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Table of Contents
Proposed Image encryption
method
9
R esult s
10
Summary / C onclusion
11

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Steganography
The art of covering a secret message within another
message or a physical object is termed as Steganography.

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History of Steganography
The word “Steganography” is derived from Greek word
“Steganographia” which consists of the words “Stegano”
meaning “covered or concealed” and “-graphia” meaning “writing”.

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Objectives of Steganography
The major objective is to share messages or
information secretly.
Few of them are:
1): Hackers use steganographic techniques, for the
transmission of viruses and malware.
2): Intelligence agencies uses steganographic
techniques for secret communications.

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Forms of Steganography
On the basis of cover media file, Steganography
can be classified into:
I): Text.
II): Audio.
III): Video.
IV): Image.

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TEXT
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In this form of Steganography, the text file
can be used as a cover media. To hide the
message a word or line can be shifted, in
the horizontal or vertical direction.

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TECHNIQUES OF TEXT STEGANOGRAPHY
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There are a lot of techniques of text
Steganography. Few of the techniques are
listed below.
a): Line shift.
b): Word shift.
c): Syntactic method.

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Line shift
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When using this method for Steganography
the text lines are shifted in the vertical
direction.

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Word shift
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To use this method, the words are shifted
horizontally. Horizontally means either in
left direction or in right direction

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Syntactic method
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In this method of data hiding punctuation
marks are used such as colon (:), semi
colon (;) etc.

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Model of Text Steganography
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AUDIO
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Audio Steganography is a technique that is
implemented in order to transfer secret
information by altering an audio signal in a
non-understanding way.

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TECHNIQUES OF AUDIO STEGANOGRAPHY
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a): LSB coding
b): Echo hiding
c): Tone insertion

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LSB CODING
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In LSB coding method, least significant bit
of binary series of audio data is replaced
with binary representation of secret data.

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ECHO HIDING
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In this method of data hiding in an audio
signal, first of all a short echo is introduced
into the host signal and then the information
is inserted in it.

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TONE INSERTION
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Tone insertion method depends upon the
embedding of low energy tones inside the
considerable higher ones.

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VIDEO STEGANOGRAPHY
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Video Steganography is an art of hiding any
kind of file into a cover video file.
The use of the video based Steganography
is more safe and secure than other
multimedia files.

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Model of Video Steganography
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Techniques of Video Steganography
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a): Secured data transmission based video
Steganography (SLSB).
b): Hash based Least Significant Technique
for video Steganography (HLSB)

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SLSB
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An approach in which data is been
inserted in the vertical and horizontal
block pixels. This approach is called
“SLSB”.

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HLSB
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In this technique, the secret data is covered
in the least significant bit of the cover
images/frames. In this technique hash
function is used to select the place of
insertion in LSB bits.

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IMAGE STEGANOGRAPHY
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Image Steganography refers to the
phenomenon of concealing data within an
image file. The image selected for this
purpose is called the cover image and the
image obtained after Steganography is
called the Stego-image.

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TECHNIQUES OF IMAGE STEGANOGRAPHY
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a): LSB insertion.
b): Encryption using Chaotic Maps.

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IMAGE
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For a computer, an image is a formation of
numbers that represent light magnitude at
different points (pixel).

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PIXEL
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A pixel is the basic building block of an
image. Means that image is the combination
of different pixels.

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TYPES OF IMAGE FORMATS
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There are a lot of image file formats. Few of
them are given below.
a): TIFF
b): JPEG
c): GIF

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TIFF
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TIFF is an acronym for Tagged Image File
Format. A TIFF is a file type that doesn’t lose
quality.

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JPEG
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The term JPEG is an acronym for Joint
Photographic Expert Group which created
this standard in 1992.

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GIF
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This is a common file type for web projects
where an image needs to load very quickly.

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CHAOTIC MAP
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A Chaotic map is a type of map that displays
some kind of chaotic behavior.
Chaotic behavior is a behavior in which
there is no specified order.

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LIST OF CHAOTIC MAPS
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Few of the Chaotic maps are mentioned below.
a): Trigonometric Chaotic Map.
b): Tent Map.
c): Logistic Map

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TRIGONOMETRIC CHAOTIC MAP
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The trigonometric chaotic map is defined by
the equation:
where xn+1 = [0 1] and λ = 1.42

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Cameraman Image.jpg (Figure 1)
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Histogram of Cameraman Image (Figure 2)
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Number
of
pixel

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Proposed Image Encryption Method
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The proposed image encryption strategy is
summed up as following.
(i) The original image is scaled into size
of 256 × 256 pixels.
(ii) Consider a random image of the same
size as original image.

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Proposed Image Encryption Method
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(iii) The original image and random image
is separated into square blocks. Each
square of size 𝑚 × 𝑚 pixels where (5) is
proposed to find 𝑚.
𝑚 = [sqrt(M*N)]/r2 (5)
where 𝑟 forms a part of the secret key.

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Proposed Image Encryption Method
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(iv) The following steps are performed on each square block
of original and random images.
a): The corresponding square of original and random images is
changed over into row vector. Perform XOR on row vector of
original image and random image to obtain a row vector.
b): A row vector, of size [1, 𝑚 × 𝑚], is obtained by using TCM to
create pseudorandom numbers. The produced numbers are
utilized as pixel location files to rearrange pixel areas of the
row vector.

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Proposed Image Encryption Method
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c): Pixel intensity estimations of the scrambled row
vector, obtained from the previous step, are changed
according to equation 6.
𝐾 = sin(𝐾+𝑏) + 𝐾 (6)
Where 𝐾 is a created key-stream by utilizing TCM and
𝑏 is the acquired line vector having perform XOR of
original and random row vectors from the past
advance.

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Proposed Image Encryption Method
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d): The resultant row vector is changed over
into a square, of size 𝑚 × 𝑚 pixels, and
secured to shape the encoded image.
(v) Pixel intensity estimations of the
encoded image are changed utilizing (6).
This step is performed to improve security
of the proposed encryption process.

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Encrypted image of Cameraman (Figure 3)
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Histogram of Encrypted Cameraman image
Number
of
pixel
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Technical Terms
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Entropy:
Entropy is defined as the amount of randomness in
adjacent image pixels.
NOTE:
 Entropy(cipher image) > Entropy (original image).
 For an encryption algorithm to be safe against
entropy attacks, the entropy value of encrypted
image must be close to 8.

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Technical Terms (contd)
Correlation coefficient:
The similarity between adjacent image
pixels are calculated by correlation
coefficient.
As, the value of correlation coefficient gets
closer to zero, the similarity between
pixels of plaintext image and cipher text
image decreases.

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Technical Terms (contd)
Peak Signal to Noise Ratio (PSNR):
To measure the quality of compressed
image and original image PSNR is used.
The higher the value of PSNR the better
the quality of compressed image.

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Experimental Results
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ORIGINAL
IMAGE
TCM BASED
ENCRYPTED
IMAGE
λ = 1.42
NCA BASED
ENCRYPTED
IMAGE
λ = 3.5
LM BASED
ENCRYPTED
IMAGE
λ = 3.97
TM BASED
ENCRYPTED
IMAGE
λ = 1.999
Entropy 7.0097 7.9772 7.0707 7.7396 7.988
Horizontal
correlation
0.9206 0.0431 0.1773 0.2304 0.0346
Vertical
correlation
0.9557 0.0203 0.0271 0.032 0.0269
Diagonal
correlation
0.9204 0.0282 0.0255 0.0295 0.0311
Average
correlation
0.9322 0.0305 0.0766 0.0973 0.0309

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Conclusion
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A one dimensional trigonometric chaotic map is
proposed. Experimental results indicate the
randomness against entropy attacks as compared
to other maps.

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Thank you
For
Your Attention
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