Cryptography Based MSLDIP Watermarking Algorithm

Abdelmgeid A. Ali & Ahmed H. Ismail
International Journal of Computer Science and
Cryptography Based MSLDIP Watermarking Algorithm
Abdelmgeid A. Ali
Faculty of Science, Computer Science Department
Minia University
Minia, 61519, Egypt
Ahmed H. Ismail
Minia University
Minia, 61519, Egypt
In recent years, internet revolution resulted in an explosive growth
rapid advancement of internet has made it easier to send the data accurate and faster to the
destination. Aside to this, it is easier to modify and misuse the valuable information through
hacking at the same time. Digital wa
protection of multimedia data. In this paper cryptography based MSLDIP watermarking method
(Modified Substitute Last Digit in Pixel) is proposed. The main goal of this method is to increase
the security of the MSLDIP technique besides to hiding the watermark in the pixels of digital
image in such a manner that the human visual system is not able to
cover image and the watermarked image. Also the experimental results showed t
can be used effectively in the field of watermarking.
Keywords: Cryptography, Encryption, Decryption, Water
(Modified Substitute Last Digit in Pixel), Security
1. INTRODUCTION
Information hiding techniques have recently become important in a number of application areas
[1]. The term hiding here can refer to either making the information imperceptible (as in
watermarking) or keeping the existence of the information secret (as in
Information hiding means communication of information by hiding in and retrieving from any
digital media. The digital media can be an image, an audio, a video or simply a plain text file.
Information hiding is a general term encompassin
encompasses three disciplines: cryptography, watermarking, and steganography [3, 4]. It is
graphically shown in (Figure 1.1), Watermarking can be robust or fragile depending upon the
application domain.
FIGU
Cryptography
Ahmed H. Ismail
International Journal of Computer Science and Security (IJCSS), Volume (9) : Issue (4) : 201
abdelmgeid@yahoo.com
ahamdycs2012@gmail.com
Abstract
In recent years, internet revolution resulted in an explosive growth in multimedia applications. The
this, it is easier to modify and misuse the valuable information through
hacking at the same time. Digital watermarking is one of the proposed solutions for copyright
rity of the MSLDIP technique besides to hiding the watermark in the pixels of digital
image in such a manner that the human visual system is not able to differentiate
cover image and the watermarked image. Also the experimental results showed that this method
can be used effectively in the field of watermarking.
Cryptography, Encryption, Decryption, Watermarking, Spatial Domain, MSLDIP
e Last Digit in Pixel), Security.
watermarking) or keeping the existence of the information secret (as in steganography) [2].
Information hiding is a general term encompassing many sub disciplines. However, generally it
FIGURE 1.1: Information Hiding Disciplines.
Information Hiding
Cryptography Steganography Watermarking
Fragile Robust
2015 208
abdelmgeid@yahoo.com
ahamdycs2012@gmail.com
in multimedia applications. The
this, it is easier to modify and misuse the valuable information through
termarking is one of the proposed solutions for copyright
rity of the MSLDIP technique besides to hiding the watermark in the pixels of digital
differentiate between the
hat this method
arking, Spatial Domain, MSLDIP
steganography) [2].
g many sub disciplines. However, generally it

Cryptography is an area within the field of cryptology. The name cryptology is a combination of
the Greek (cruptos = hidden and logos = study, science). Therefore, the word cryptology literally
implies the science of concealing. The cryptography can be divided into two areas: cryptography
and cryptanalysis [5]. Cryptanalysis is the area within cryptology which is conc
techniques for deciphering encrypted data without prior knowledge of which key has been used.
This more commonly known as 'Hacking'.
weaknesses in encryption schemes. He will often figure out how
scheme, and then the developer of the scheme will use that information to make it stronger [6].
When people initially tried to communicate over distances, they tried to ensure the secrecy of
their communications. The technology of
steganography comes from two Greek words stegauw (steganos) and grafein (graphein) meaning
covered writing. It is basically about embedding a secret message in a cover file [8] which looks
innocuous. This cover file could be an image file, video file, audio file, text file, or any computer
code [4, 9]. Steganography is comprised of two algorithms, one for embedding and one for
extraction [10]. A great deal of attention is paid to ensuring that the secr
unnoticed if a third party were to intercept the cover file [11].
Watermarking is a technique used to hide data or identifying information within digital multimedia.
The discussion will focus primarily on the watermarking of digital images,
audio, and documents are also routinely watermarked. Digital watermarking is becoming popular,
especially for adding undetectable identifying marks, such as author or copyright information.
digital watermarking process embeds a s
visual quality. Digital watermarking is a process to embed some information called watermark into
different kinds of media called Cover Work [3, 12]. Digital watermarking is used to hide the
information inside a signal, which cannot be easily extracted by the third party. Watermarking is
used for following reasons, Proof of Ownership (copyrights and IP protection), Copying
Prevention, Broadcast Monitoring, Authentication, Data Hiding. Digital watermar
research direction for the technique of information hiding, mainly including the characteristics
(capacity, invisibility, security, robustness).
2. RELATED WORK
In this section, the MSLDIP Watermarking algorithm will be presented which works
domain of the cover image. At the first the (SLDIP) will be presented before the (MSLDIP)
method. SLDIP method takes the cover image and the watermark as input, convert the blue layer
of the cover image into one row, and divide the row into
then consider the watermark is color image then each pixel will be represented in 3 bytes,
according to the color image representation (which each pixel is specified by three values one
each for red, blue, and green components of the pixel's color and each value represented by one
byte, so each pixel will be represented in three bytes) [13].
Each byte in the watermark image will be ranges from 0 to 255, and make each byte value's
length equal to 3 digits, for exampl
length of 3 digits, finally substitute each 9 digits of each pixel with the last digit of each pixel in the
current block, so each pixel of the watermark image will be embedded in only one block
output the watermarked image and 2 keys which be required in the extraction process (Figure
2.1) and (Figure 2.2) [14].
FIGURE 2.1
input:
cover Image.
watermark.
Ahmed H. Ismail
= hidden and logos = study, science). Therefore, the word cryptology literally
Cryptanalysis is the area within cryptology which is conc
This more commonly known as 'Hacking'. The cryptanalyst is the person who tries to find
weaknesses in encryption schemes. He will often figure out how to break the cryptography
their communications. The technology of steganography is developed for this goal [7]. The word
This cover file could be an image file, video file, audio file, text file, or any computer
extraction [10]. A great deal of attention is paid to ensuring that the secret message goes
unnoticed if a third party were to intercept the cover file [11].
The discussion will focus primarily on the watermarking of digital images, though digital video,
especially for adding undetectable identifying marks, such as author or copyright information.
digital watermarking process embeds a signal into the media without significantly degrading its
ion inside a signal, which cannot be easily extracted by the third party. Watermarking is
Prevention, Broadcast Monitoring, Authentication, Data Hiding. Digital watermark is an important
(capacity, invisibility, security, robustness).
In this section, the MSLDIP Watermarking algorithm will be presented which works
of the cover image into one row, and divide the row into blocks each of which contains 9 values,
components of the pixel's color and each value represented by one
byte, so each pixel will be represented in three bytes) [13].
length equal to 3 digits, for example we have byte of value 15, this value equal to 015 which has
current block, so each pixel of the watermark image will be embedded in only one block
2.1: SLDIP Watermarking Embedding Process [14].
input:
cover Image.
watermark.
SLDIP
Embedding
:output
watermarked
img
key1.
key2.
2015 209
= hidden and logos = study, science). Therefore, the word cryptology literally
Cryptanalysis is the area within cryptology which is concerned with
The cryptanalyst is the person who tries to find
to break the cryptography
steganography is developed for this goal [7]. The word
This cover file could be an image file, video file, audio file, text file, or any computer
et message goes
though digital video,
especially for adding undetectable identifying marks, such as author or copyright information. The
ignal into the media without significantly degrading its
ion inside a signal, which cannot be easily extracted by the third party. Watermarking is
k is an important
In this section, the MSLDIP Watermarking algorithm will be presented which works on the spatial
blocks each of which contains 9 values,
components of the pixel's color and each value represented by one
e we have byte of value 15, this value equal to 015 which has
current block, so each pixel of the watermark image will be embedded in only one block, and

FIGURE 2.2
Assuming that watermark image of height 1 pixels and width 1 pixels, and cover image of height 3
pixels and width 3 pixels. The SLDIP will represent the cover image in one row which contains
one block of 9 values (125, 255, 086, 192, 145, 210, 035, 099, and 004), a
image will be represented as (230, 105, and 080), the SLDIP will substitute 5 (last digit in cover
image) in 125 with 2 (first digit in watermark image) in 230, the result is 122 and also substitutions
done until reaching the last digit in
be (122, 253, 080, 195, 140, 215, 030, 098, and 000) [13].
By using this method capacity of embedding has been increased, the maximum area of
watermark image that can be embedded in any cover im
formula [14]:
‫ݐܹ݀݅݁݃ܽ݉ܫ‬
If the watermark image is grayscale image this formula can be used:
‫ݐܹ݀݅݁݃ܽ݉ܫ‬
Supposing a (8 x 8) cover image, by using equation 1, we can embed colored watermark image
of area 7 pixel2 which approximately equals to (2 x 3) colored watermark image, and by using
equation 2, a grayscale watermark
grayscale watermark image can be embedded. Notice that SLDIP uses only one layer of the color
image neither two nor three layers. This means that we can use this method in color and
grayscale images [14].
MSLDIP is a modification on SLDIP by update the substitution step to decrease the difference
between the original pixel and the substituted pixel, for example embedding value digit 9 in pixel
100, by using SLDIP the pixel will be 109, but by MS
each substitution and choose the value that has the smallest difference, so the two values will be
109 and 99, then the value with the smallest difference must be chosen, so the pixel value will be
99, the difference will be 1 instead of 9 and this increases the PSNR value of the image [14].
3. PROPSED METHOD
In this section the proposed method will be presented, at the first the proposed method will be
divided into two algorithms which are Watermark embedding
algorithm.
3.1 Watermark Embedding Algorithm
Algorithm: Secured MSLDIP Embedding Algorithm
Input: Watermark W; Cover Image C; Secret Key K.
Output: Encrypted Watermark W', Secured Watermarked Image SWI.
Steps: (Figure 3.1)
1. Take W and encrypt it by performing RC4 Encryption algorithm with K, the output of this
step is called W'.
2. Apply MSLDIP Watermarking Embedding procedure to embed W' in C, the output of this
step is called secured watermarked image SWI.
input:
watermarked img
key1.
key2.
Ahmed H. Ismail
2.2: SLDIP Watermarking Extraction Process [14].
that watermark image of height 1 pixels and width 1 pixels, and cover image of height 3
one block of 9 values (125, 255, 086, 192, 145, 210, 035, 099, and 004), and the watermark
done until reaching the last digit in the last value of the watermark. The watermarked image will
be (122, 253, 080, 195, 140, 215, 030, 098, and 000) [13].
watermark image that can be embedded in any cover image can be calculated by using this
‫ ݄ݐܹ݀݅݁݃ܽ݉ܫ‬ ൈ ‫ݐ݄݃݅݁ܪ݁݃ܽ݉ܫ‬
9
ൌ ‫݇ݎܽ݉ݎ݁ݐܽݓ‬௔௥௘௔ ሺ1ሻ ሾ14ሿ
If the watermark image is grayscale image this formula can be used:
‫ ݄ݐܹ݀݅݁݃ܽ݉ܫ‬ ൈ ‫ݐ݄݃݅݁ܪ݁݃ܽ݉ܫ‬
3
ൌ ‫݇ݎܽ݉ݎ݁ݐܽݓ‬௔௥௘௔ ሺ2ሻ ሾ14ሿ
(8 x 8) cover image, by using equation 1, we can embed colored watermark image
equation 2, a grayscale watermark image of area 21 pixel2 which approximately equals to (4 x 5)
100, by using SLDIP the pixel will be 109, but by MSLDIP two possible values can be taken for
ce will be 1 instead of 9 and this increases the PSNR value of the image [14].
divided into two algorithms which are Watermark embedding algorithm and watermark extraction
Watermark Embedding Algorithm
Secured MSLDIP Embedding Algorithm.
Watermark W; Cover Image C; Secret Key K.
Encrypted Watermark W', Secured Watermarked Image SWI.
Take W and encrypt it by performing RC4 Encryption algorithm with K, the output of this
Apply MSLDIP Watermarking Embedding procedure to embed W' in C, the output of this
step is called secured watermarked image SWI.
input:
watermarked img
.
.
SLDIP
Extracting
:output
watermark
2015 210
that watermark image of height 1 pixels and width 1 pixels, and cover image of height 3
nd the watermark
the last value of the watermark. The watermarked image will
age can be calculated by using this
(8 x 8) cover image, by using equation 1, we can embed colored watermark image
image of area 21 pixel2 which approximately equals to (4 x 5)
LDIP two possible values can be taken for
ce will be 1 instead of 9 and this increases the PSNR value of the image [14].
algorithm and watermark extraction
Take W and encrypt it by performing RC4 Encryption algorithm with K, the output of this
Apply MSLDIP Watermarking Embedding procedure to embed W' in C, the output of this

FIGURE
3.2 Watermark Extraction Algorithm
Algorithm: Secured MSLDIP Extraction
Input: Secured Watermarked Image SWI; Secret Key K.
Output: Encrypted Watermark W', Watermark W.
Steps: (Figure 3.2)
1. Apply procedure MSLDIP extraction to extract the encrypted watermark from SWI, the
output of this step is called W'.
2. Take W' and decrypt it by performing RC4 Decryption algorithm using K, the output of this
step is called W.
FIGURE
4. EXPERIMENTAL RESULTS
In order to evaluate the performance of the watermarked images, there are some quality
measures such as PSNR and MSE.
The MSE (Mean Square Root)
image and a distorted image. It can be calculated by the formula given below
‫ܧܵܯ‬
Where X and Y are height and width respectively of the cover image, the c(i, j) is the pixel value
of the cover image and e(i, j) is the pixel value of the watermarked image.
The PSNR (Peak Signal to Noise Ratio)
possible value (power) of a signal and the power of distorting noise that affects the quality of its
representation. It can be calculated by the formula as
Where L is the peak signal value of the
In order to make the watermarking algorithm more secured, RC4 Encryption
with the MSLDIP Embedding Algorithm (Figure 4.1),
Algorithm is merged with the MSLDIP Extraction Algorithm as anyone can know the MSLDIP
watermarking algorithm and do the reverse of embedding algorit
Input
Input
Ahmed H. Ismail
GURE 3.1: Modified MSLDIP Embedding Process.
Watermark Extraction Algorithm
Extraction Algorithm.
Secured Watermarked Image SWI; Secret Key K.
Encrypted Watermark W', Watermark W.
procedure MSLDIP extraction to extract the encrypted watermark from SWI, the
output of this step is called W'.
Take W' and decrypt it by performing RC4 Decryption algorithm using K, the output of this
FIGURE 3.2: Modified MSLDIP Extraction Process.
EXPERIMENTAL RESULTS
measures such as PSNR and MSE.
MSE (Mean Square Root) is defined as an average squared difference between a reference
and a distorted image. It can be calculated by the formula given below
‫ܧܵܯ‬ ൌ
ଵ
௑௒
ൣ∑ ∑ ሺܿሺ݅, ݆ሻ െ ݁ሺ݅, ݆ሻሻଶ௒
௝ୀଵ
௑
௜ୀଵ ൧ (3)
is the pixel value of the watermarked image.
PSNR (Peak Signal to Noise Ratio) is an expression for the ratio between the maximum
can be calculated by the formula as
ܴܲܵܰ ൌ 10 ݈‫݃݋‬ଵ଴ ൬
‫ ܮ‬ ൈ ‫ܮ‬
‫ܧܵܯ‬
൰ ሺ4ሻ
is the peak signal value of the cover image which is equal to 255 for 8 bit images [15].
In order to make the watermarking algorithm more secured, RC4 Encryption Algorithm is merged
mbedding Algorithm (Figure 4.1), and in the other hand RC4 Decryption
watermarking algorithm and do the reverse of embedding algorithm and so the watermark can be
•W
•K
Input
•W'
•C
RC4
Encryption
SWIEmbedding
Algorithm
SWIInput
•W'
•K
Extraction
Algorithm
W
RC4
Decryption
2015 211
procedure MSLDIP extraction to extract the encrypted watermark from SWI, the
Take W' and decrypt it by performing RC4 Decryption algorithm using K, the output of this
is defined as an average squared difference between a reference
is an expression for the ratio between the maximum
cover image which is equal to 255 for 8 bit images [15].
Algorithm is merged
and in the other hand RC4 Decryption
hm and so the watermark can be

known, but by using an encryption algorithm the user who doing the reverse of the MSLDIP
embedding algorithm must know the key to extract the correct watermark, if the key has been
entered is incorrect the watermark will be f
Modified MSLDIP have been implemented in MATLAB 2014 platform and the experiment has
been conducted on various images.
FIGURE
Watermarking
FIGURE 4.2
when input can be correct key and incorrect key
Modified MSLDIP Watermarking has been applied on set of images different in sizes and the
Peak Signal to Noise Ratio (PSNR), and Mean Square Root (MSE) have been ca
results recorded in (Table 1).
Cover Image (a)
Correct Watermark (a)
When Key is Correct
Ahmed H. Ismail
entered is incorrect the watermark will be fake (Figure 4.2).
been conducted on various images.
FIGURE 4.1: Embedding a, b using Modified MSLDIP
Watermarking to output the watermarked image c.
4.2: Watermark Extraction using Modified MSLDIP
when input can be correct key and incorrect key.
Peak Signal to Noise Ratio (PSNR), and Mean Square Root (MSE) have been ca
Cover Image (a)
(500 x 500)
Watermark (b)
(50 x 50)
Watermarked Image (c)
(500 x 500)
Correct Watermark (a)
When Key is Correct
Fake Watermark (b)
When key is incorrect
Watermarked Image (c)
(500 x 500)
2015 212
Peak Signal to Noise Ratio (PSNR), and Mean Square Root (MSE) have been calculated, all

Cover Image
(150 x 150)
(200 x 200)
(500 x 500)
(700 x 700)
(1000 x 1000)
TABLE 1: Results of applying Modified MSLDIP watermarking on various sizes images
In (Figure 4.3), Chart showing the results of MSE and PSNR between the cover image and
watermarked image in the Modified MSLDIP Algorithm.
FIGURE 4.3
Modified MSLDIP has been compared with [16] (Table 2), supposed four cover image with
squared sizes 128, 256, 512, and 1024, and a watermark with full capacity with cover images
according to [16], thus the full watermark capacit
according to [16] by using formula
ܴ‫ ݌ݑ ݀݊ݑ݋‬ ቌඨ
‫ݐܹ݀݅݁݃ܽ݉ܫ‬
Then Modified MSLDIP has been compared with [14] (t
results have been approximately equal to each other but in the modified MSLDIP the user who
extracting the watermark from the watermarked image must have the key to get the correct
watermark if not the watermark w
fake, thus the Modified MSLDIP can be better than MSLDIP as the first one is more secured than
the other.
Finally the Modified MSLDIP has been compared with [17], supposed the grayscale baboon.bmp
as a cover image and, the grayscales lena.bmp, and barbara.bmp as watermark and the full
capacities of the embedded watermark according to each algorithm have been calculated using
formulas
(1000
IMAGESIZE
watermarked images (Modified MSLDIP)
Ahmed H. Ismail
Image PSNR MSE Watermark Image
43.21 3.11 (50 x 50)
45.87 1.68 (50 x 50)
53.29 0.31 (50 x 50)
56.22 0.16 (50 x 50)
(1000 x 1000) 59.82 0.07 (50 x 50)
Results of applying Modified MSLDIP watermarking on various sizes images
watermarked image in the Modified MSLDIP Algorithm.
4.3: Chart showing the results of Modified MSLDIP.
according to [16], thus the full watermark capacity can be calculated using cover image sizes
according to [16] by using formula
‫ ݄ݐܹ݀݅݁݃ܽ݉ܫ‬ ൈ ‫ݐ݄݃݅݁ܪ݁݃ܽ݉ܫ‬
24
ቍ ൌ ‫ ݄ݐ݈݃݊݁ ݁݀݅ݏ ݇ݎܽ݉ݎ݁ݐܽݓ‬
Then Modified MSLDIP has been compared with [14] (the previous version method) (Table 3), the
watermark if not the watermark which has been extracted from the watermarked image will be
43.21
45.87
53.29
56.22
59.82
3.11
1.68
0.31
0.16
0.07
0 20 40 60 80
(150 x 150)
(200 x 200)
(500 x 500)
(700 x 700)
1000 x 1000)
PSNR & MSE
PSNR and MSE between cover and
watermarked images (Modified MSLDIP)
MSE PSNR
2015 213
Results of applying Modified MSLDIP watermarking on various sizes images.
y can be calculated using cover image sizes
ሺ5ሻ
he previous version method) (Table 3), the
hich has been extracted from the watermarked image will be

International Journal of Computer Science and Security (IJCSS), Volume (9) : Issue (4) : 2015 214
ܴ‫ ݌ݑ ݀݊ݑ݋‬ ቌඨ
‫݄ݐܹ݀݅݁݃ܽ݉ܫݎ݁ݒ݋ܥ‬ ൈ ‫ݐ݄݃݅݁ܪ݁݃ܽ݉ܫݎ݁ݒ݋ܥ‬
3
ቍ
ൌ ‫ ݄ݐ݈݃݊݁ ݁݀݅ݏ ݇ݎܽ݉ݎ݁ݐܽݓ‬ሺ‫ܲܫܦܮܵܯ ݂݀݁݅݅݀݋ܯ‬ሻ ሺ6ሻ
ܴ‫ ݌ݑ ݀݊ݑ݋‬ ቌඨ
‫݄ݐܹ݀݅݁݃ܽ݉ܫݎ݁ݒ݋ܥ‬ ൈ ‫ݐ݄݃݅݁ܪ݁݃ܽ݉ܫݎ݁ݒ݋ܥ‬
8
ቍ
ൌ ‫ ݂݋ ݄ݐ݈݃݊݁ ݁݀݅ݏ ݇ݎܽ݉ݎ݁ݐܽݓ‬ሾ14ሿ ሺ7ሻ
Cover Image
Watermark
FC [10]
[16] 3rd Bit Modified MSLDIP
PSNR MSE PSNR MSE
Baboon 128 ( 27 x 27 ) 31.68 dB 44.50 46.90 dB 1.33
Bird 256 ( 53 x 53 ) 31.68 dB 44.50 46.99 dB 1.30
Boat 512 (125 x 125) 31.68 dB 44.50 46.10 dB 1.60
Pepper 1024 (210 x 210) 31.68 dB 44.50 47.17 dB 1.25
TABLE 2: Results Comparison between [16] 3
rd
Bit and Modified MSLDIP.
Cover Image
Watermark
Image
[14] MSLDIP Modified MSLDIP
PSNR MSE PSNR MSE
( 600 x 600 ) ( 200 x 200 ) 43.10 dB 3.18 43.06 dB 3.22
( 768 x 768 ) ( 200 x 200 ) 45.66 dB 1.77 45.63 dB 1.78
( 1024 x 1024 ) ( 200 x 200 ) 48.23 dB 0.98 48.22 dB 0.98
( 1280 x 1280 ) (200 x 200) 49.69 dB 0.67 49.46 dB 0.74
( 1500 x 1500 ) ( 200 x 200 ) 51.29 dB 0.48 51.19 dB 0.49
TABLE 3: Results Comparison between [14] MSLDIP and Modified MSLDIP.
Cover Image
Watermark
Image
[17] Modified MSLDIP
PSNR PSNR
baboon.bmp
(512 x 512)
lena.bmp
(64 x 64)
58.64 dB 52.00 dB
baboon.bmp
(512 x 512)
Barbara.bmp
(64 x 64)
58.99 dB 51.81 dB
Watermark (FC) applying equations
(6,7) With Cover Image size (512 x 512)
(181 x 181) (295 x 295)
TABLE 4: Results Comparison between [17] and Modified MSLDIP.

5. COMPARATIVE EVALUATION
From the comparison in table (2), the reason of why Modified MSLDIP has been compared with
[16] 3rd Bit? Has been clarified as, in Modified MSLDIP substitutions can change the value of
pixel which the difference ranges from 0 to 5 and change in the 3rd Bit in pixel can change the
value of pixel which the difference ranges from 0 to 7 which include the Modified MSLDIP
difference range. However results in Modified MSLDIP are better.
From the comparison in table (3), the results of the modified MSLDIP are compared with the
results of the MSLDIP [14] (the previous version), and It can be concluded that the results were
very close, as the difference didn't not exceed the one after the decimal point, but in the modified
MSLDIP the data which has been watermarked is more secured with a key, it can be proved that
the modified MSLDIP technique is better.
From the comparison in table (4), the results of modified MSLDIP are compared with results of
[17], and from the comparison it can be concluded that the two algorithm have very good PSNR
results that mean no one can discover the watermark when looking at the image, also it can be
conducted that the watermark full capacity of modified MSLDIP is greater than [17], suppose
cover image (512 x 512) and watermark (256 x 256) algorithm of [17] cannot embed the
watermark in cover image but the modified MSLDIP can embed this watermark successfully.
After Implementing and analyzing the results, conclude that, the visual quality of the image
doesn't change significantly, on the other hand this algorithm is more robust than LSB technique
[17], because in LSB technique some attackers can possibly zero out several least significant bit
of pixels of the image and hence clear the watermark. This technique has increased the capacity
of watermark in embedding process.
6. CRITICAL DISCUSSION
Watermarking algorithm proposed in [16], the full capacity of watermark which can be embedded
in cover image of size 128x128 pixels is 682.67 px
2
that approximately equal to watermark of size
26x26 pixels however in our proposed method the full capacity of watermark is 1280.44 px
2
that
approximately equal watermark of size 42x42 pixels, that mean our proposed method can embed
watermark with capacity larger than [16], also in [16] there isn't any way to prevent unauthorized
users from accessing the watermark, however in our proposed method the watermark is
encrypted using RC4 with a key which only users who have this key can access the watermark,
that mean in our proposed method the watermark is more secured.
Watermarking algorithm proposed in [14], regardless of it can embed watermark with capacity
equal to our proposed method, in [14] there isn't any way to prevent unauthorized users from
accessing the watermark, however in our proposed method the watermark is encrypted using
RC4 with a key which only users who have this key can access the watermark that mean in our
proposed method the watermark is more secured.
Watermarking algorithm proposed in [17], the full capacity of watermark which can be embedded
in cover image of size 512x512 pixels is 32768 px
2
that approximately equal to watermark of size
181x181 pixels however in our proposed method the full capacity of watermark is 87381.33 px
2
that approximately equal watermark of size 295x295 pixels, that mean our proposed method can
embed watermark with capacity larger than [17], also in [17] there isn't any way to prevent
unauthorized users from accessing the watermark, however in our proposed method the
watermark is encrypted using RC4 with a key which only users who have this key can access the
watermark, that mean in our proposed method the watermark is more secured.
7. CONCLUSION
Digital watermarking with cryptography is the current area of research where lot of scope exists.
Currently digital watermarking with cryptographic technique is being used by several countries for
secretly transfer of hand written documents, text images, financial documents, internet voting etc.

This paper starts from some basic knowledge of information hiding categories includes digital
image watermarking, and from results conclude that the visual quality of the image doesn't
change significantly, this algorithm is more robust than LSB technique because in LSB technique
some attackers can possibly zero out several least significant bit of pixels of the image and hence
clear the watermark, this algorithm is more secure because of using cryptographic technique
which has been merged with the watermarking technique, and this technique has increased the
capacity of watermark which will be embedded. In the future, the aim of this paper is to extend the
cryptography to higher dimensions and apply it in frequency domain in order to consider more
security and robustness.
8. REFERENCES
[1] F. A. P. Petitcolas, R. J. Anderson and M. G. Kuhn, "Information Hiding – A Survey",
proceedings of the IEEE, Special Issue on Protection of Multimedia Content, vol. 87(7), pp.
1062 - 1078, July 1999.
[2] I. J. Cox, m. L. Miller, J. A. Bloom, J. Fridrich and T. Kalker, "Digital Watermarking and
Steganography", ISBN 978-0-12-372585-1, 2nd edition, Elsevier inc, 2008.
[3] Preeti Gupta, “Cryptography based digital image watermarking algorithm to increase
security of watermark data”, International Journal of Scientific & Engineering Research,
Volume 3, Issue 9 (September 2012) ISSN 2229-5518.
[4] J. A. Mathew, "Steganographic Techniques for Subliminal Communication in Open Systems
Environment", Sam Higginbottom Institute of Agriculture, Technology and Sciences, PHD.
Thesis, 2010.
[5] Jan C A, Van Der Lubbe, "Basic Methods of Cryptography", English translation Cambridge
University Press 1998.
[6] E. Cole, "Hiding In Plain Sight: Steganography and The Art of Covert Communication", ISBN
0-471-44449-9, Wiley publishing, inc, 2003.
[7] S. A. Baker and Dr. A. S. Nori, "Steganography in Mobile Phone over Bluetooth",
International Journal of Information Technology and Business Management (JITBM),
Volume 16, Number 1, Pages 111- 117, 29 August 2013.
[8] T. Morkel, "Image Steganography Applications for Secure Communication", Master of
Science (Computer Science) Thesis, Faculty of Engineering, Built Environment and
Information Technology University of Pretoria, Pretoria, May 2012.
[9] F.C.Gonzalez, "Counter Terrorist Steganography Search Engine", Master of Science
Thesis, Department of Aerospace, Power and Sensors, Royal Military College of Science,
Shrivenham, Cranfield University, 2002.
[10] S. A. Sohag, Dr. M. K. Islam and M. B. Islam, "American Journal of Engineering Research
(AJER)", Volume 2, Issue 9, Pages 118 - 126, 2013.
[11] S.Deepa and R.Umarani, "A Study on Digital Image Steganography", International Journal
of Advanced Research in Computer Science and Software Engineering, International
Journal of Advanced Research in Computer Science and Software Engineering, Volume 3,
Issue 1, January 2013.
[12] B Surekha, Dr GN Swamy, “A Spatial Domain Public Image Watermarking”, International
Journal of Security and Its Applications Vol. 5 No. 1, January, 2011M. Abdullatif, A. M. Zeki,
J. Chebil, and T. S. Gunawan, "Properties of Digital Image Watermarking".

[13] Ahmed A. Radwan, Ahmed Swilem, Al-Hussien Seddik, "A High Capacity SLDIP method",
ICICIS, July 2011.
[14] Abdelmgeid A. Ali, Ahmed A. Radwan, and Ahmed H. Ismail, "Digital Image Watermarking
using MSLDIP (Modified Substitute Last Digit in Pixel)", IJCA, Volume 108 – No 7, Pages
30-34, December 2014.
[15] Amit Kumar Singh, Nomit Sharma, Mayank Dave, Anand Mohan, "A Novel Technique for
Digital Image Watermarking in Spatial Domain", 2012 2nd IEEE International Conference on
Parallel, Distributed and Grid Computing.
[16] Deepshikha Chopra, Preeti Gupta, Gaur Sanjay, Anil Gupta, "LSB based digital image
watermarking for gray scale image", IOSRJCE, October 2012.
[17] Krishna Kumar, and Shashank Dwivedi, "Digital Watermarking using Asymmetric Key
Cryptography and Spatial Domain Technique", IJARCSMS, Volume 2, Issue 8, August
2014.

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