
Research Article


Symmetric CryptoGraphical Model 

Fawaz Alsaade



ABSTRACT

Financial institutions play an important role in the development of a country. There are numerous ways to perform banking transactions. The main objective of this study is to fill the gap between electronic banking and conventional banking. The study presented a modular approach between electronic banking system and conventional banking system along with a flow chart. Normally in banking, user’s authenticity is based on the verification of customer’s signature, therefore, this study highlighted the solution of signature verification having different background, the issues regarding banking transactions and provided appropriate solutions for electronic banking system. However, in today’s banking, cheques play a vital role but for electronic banking digital currency is needed. Overall, the solution and implementation of electronic money with conventional cheques is discussed in detail. Furthermore, the study tried to focus on the security of any image using symmetric key encryption.







INTRODUCTION
Image plays a key role in the development of industry and education such that most of the time it keeps secrets. Presently, thousands of images are taken per day to record history. Image is the composite form of small units called pixels or picture elements. This study tried to focus on the security of any image using symmetric key encryption.
In the fastest cyber world, image plays a vital role for almost every electrical
transaction with security to be very high priority for all transactions. In
order to send and receive data, support of third party is needed and the risk
is always associated with it. Therefore, a smart algorithm is required that
will convert the important images into cipher and only the authorized persons
can see that image after decrypting it. Since, image is one of the most important
communication information, therefore, image encryption is considered a hot and
an important research realm in secret communications, information security and
copyright protection, etc. On the basis of thorough study of twodimensional
data structural characteristic of digital images, made adequate use of many
inherent excellences of chaotic systems for security communications and information
encryption such as nonperiodicity, randomness, turbulence, good statistic characteristic,
easy regeneration, wondrous sensitivity for initial values (Dinghui
et al., 2008). Here an effective and sufficiently secure algorithm
for image encryption was implemented.
Mallat and Tuunainen (2005) reported that wide enough
acceptance and adoption of mobile payment technologies and systems is a prerequisite
for consumer adoption of many, if not most, mobile commerce services. They presented
results from two, concurrent sets of empirical data on merchant adoption of
mobile payment systems. In addition to the potential advantages of mobile payments,
they also identified several barriers to their adoption, most clearly in four
categories: relative advantage, compatibility, complexity and costs Claessens
et al. (2002) stated that current technology is evolving fast and
is constantly bringing new dimensions to our daily life. Electronic banking
systems provide us with easy access to banking services. The interaction between
user and bank has been substantially improved by deploying ATMs, phone banking,
Internet banking, and more recently, mobile banking. This study discussed the
security of today’s electronic banking systems. The study focused on Internet
and mobile banking and presented an overview and evaluation of the techniques
that are used in the current systems. The issues discussed in this study are
generally applicable in other electronic services such as ecommerce and egovernment.
Menezes et al. (1996) stated that the general
security requirements applied to electronic banking systems are (1). Confidentiality:
Ensures that only authorized entities have access to the content of the exchanged
information e.g., an eavesdropper should not be able to find out what transactions
a particular user is executing, (2) Entity authentication: users should
be sure that they are communicating with the real bank, before sending sensitive
information to it; banks should know the identity of a user before processing
its transactions, (3) Data authenticationi.e., data origin authentication and
data integrityallows one to detect manipulation and replay of data, by unauthorized
parties; data manipulation includes insertion, deletion and substitution e.g.,
users and the bank want to be sure that the information they receive is genuine
and fresh (not replayed) and (4) Nonrepudiation: prevents an entity from denying
previous commitments or actions e.g., a bank should be able to prove to a third
party that a user performed a certain transaction, in case that user denies
having performed it.
ENCRYPTION METHOD
Image is generally a combination of rows and columns or MxN, if the number
of rows and columns increases, it means more and more data is present in the
matrix that is generally called mega pixels image. In this case, still image
for encryption is being used and its mathematical formula is given below:
S= f (x, y), 0≤x≤m; 0≤y≤n 
where, m denotes the width of the image and n denotes the height of the image;
for any point (x, y) in the region, f (x, y) denotes the pixel value of which
point. Without the loss of the generality, the 256 degree gray image is being
used as an example to explain the encryption, so the expression S= f (x, y)
will denote the gray value in this study. The gray value corresponding to any
point in a gray image is finite (0~255), so the value of the formula S = f (x,
y) is limited. After the image has been digitalized, the formula S = f (x, y),
corresponds a matrix. The row and column of each matrix element is the coordinate
of the image displayed on a computer screen, and any element value of the matrix
is the gray value of the related point (Dan and Xiaojing,
2008).
Initialization
Input
Load of Image for Encryption i.e.,
P_{RGB} = {bij; 1≤ i≤M 1≤ j≤N} where P is the input image, M is the height of RGB image and N is the width of the RGB image.
Mathematical form of RGB image mask is as follows:
Method
Encryption
First step is to encrypt an image by multiplying P image matrix with private
key Kr and assigning new name of the matrix with P`.
• 
P`: 
= 
P_{RGB}.Kr 
• 
P` 
= 
K_{r}.P 
Matrix shows the first form of encryption which is represented by P`. It is
the product of pixel values private key Kr. The mathematical explanation of
the above matrix is given below:
where as:
This is the second part of an encryption. In this case, the above matrix is
encrypted into special ASCII code which is then used as cipher for transmission.
It is secure as if anybody wants to decrypt that code he got nothing but the
special code:
Now the desired image is twice encrypted and ready to transmit to its destination.
This image can be decrypted with this algorithm only with the help of its private
key. The various decryption steps are as follows.

Fig. 1: 
Symmetric image encryption model 
Now convert the encrypted matrix into ASCII code and then divide the new matrix
by symmetric private key.
Now this algorithm will help us to retrieve the original image. This encryption
and decryption in Matlab was tested and then proposed a system. Encryption and
decryption of an image are shown in Fig. 1 and 2.
EXPERIMENTS AND TESTING
Many researchers have already proposed different encryption and decryption
models such as Elliptic Curve Integrated Encryption Scheme (ECIES) where public
key and private key are used for encryption and decryption (Guan
et al., 2008). The chaotic algorithms such as Chaotic KeyBased Algorithm
(CKBA) were proposed by Yen and Guo (1999a, b,
2000) in which a binary sequence as key is generated
using chaotic system, and the image pixels are arranged according to the generated
binary sequence, and then the scalegray values of pixels are XORed or XNORed
bitbybit to one of the two predetermined keys.

Fig. 2: 
Result of image encryption 

Fig. 3: 
The resultant images (a) original and (b) encrypted 
Most of the experiments are combination of chaotic and discrete wavelet transform
which are used for image transformation and coding (Delei
et al., 2008). The Encryption filter is another way in this regard
and it explains the advantage of large number of knight's tour, let the encryptionfilter
template matrix move along with the Knight’s tour slip matrix and does
the convolution (Wang et al., 2008).
Actually, the present experiments were chaotic based and the results were tested
with the help of Mat laboratory for encryption and decryption which are so simple
and easy to implement but private key is the only way of decryption. The resultant
images are presented in Fig. 3.
CONCLUSION
The study proposed a new and effective scrambling method of image encryption based on chaotic encryption using private key. This algorithm was based on a private key encryption where as a single key is used in encryption and decryption and the size of key image can be much smaller than the secret image.

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