PERFORMANCE ENHANCEMENT IN IMAGE
ENCRYPTION USING AES
Dr.Somesh Kumar Rajput
1,
Anuradha Konidena
2
1
Professor & HOD, Department of Information Technology, NIET, Greater NOIDA
2
Research Scholar(Computer Science and Engineering), Noida Internatonal University
Abstract: In rapidly growing internetwork era safe and secure transfer of data is major issue of concern. Most of
the data being transferred consists of images. Cryptography is one of the methods that ensure Security. Advanced
Encryption Standard (AES) is a specification for the encryption of electronic data. It has been adopted by the U.S.
government and is now used worldwide. Modified AES is proposed in this paper which is useful for applications
like GIS.
Key words: AES,, Image Encryption, Internet, RGB images, Security.
I. Introduction : The ever advancement in technology and
faster than exhaustive search, they are completely non-
revolution in image processing augmented the need of
practical, and do not seem to pose any real threat to the
transmission of secure images .Cryptography plays crucial role in
security of AES-based systems. Image encryption is
providing security. Cryptography involves encryption and
required in almost all applications like military image
decryption. Algorithms that are used to encrypt text need to be
databases,
enhanced before the same will be used for image encryption
imaging system, cable TV, online personal photograph
because size of the image will be very high as compared to text
and images contain correlated pixels. Among the algorithms that
are used for image encryption, Advanced Encryption Standard
(AES) is efficient. AES is a symmetric-key algorithm, meaning
confidential
video
conferencing,
medical
album, security is crucial factor for all the above said
applications. Advanced Encryption Standard (AES) is a
famous and strong encryption algorithm which has several
the same key is used for both encrypting and decrypting the data.
advantages in data ciphering. However, AES suffer from
AES is the best known and most widely used block cipher. Its
some drawbacks such as high computations, pattern in
three versions (AES-128, AES-192, and AES-256) differ in their
ciphered images, and hardware requirement. Those
key sizes (128 bits, 192 bits and 256 bits) and in their number of
problems are more complicated when AES algorithm is
rounds (10, 12, and 14, respectively). In the case of AES-128,
used for images ciphering. This paper is organized into V
there is no known attack which is faster than the 2
128
complexity
of exhaustive search. However, AES-192 and AES-256 were
recently shown to be breakable by attacks which require 2
2
119
176
time, respectively. While these complexities are much
sections. Section-I contains introduction about AES and
Section-II describes related work in this field and proposed
method is briefed in Section-III. Section-IV describes about
and
various
Security
Analysis
Metrics
of
Image
Encryption,which proposed system should satisfy and this
paper is concluded with SectionV, which lists References.
2. Literature Review
M. Zeghid, M. Machhout, L. Khriji, A. Baganne, and
in the cipher, Mix column operation creates diffusion.
This methodology helps in creating secure images,
where size of the image is big like GIS.
R. Tourki [1] proposed the idea of extension of AES
to support a key stream generator for image
IV.Security Analysis Metrics of Image Encryption:
encryption which can overcome the problem of
textured zones existing in other known encryption
algorithms. Hasan and Hegazy [2] proposed an
To Ensure the Security, proposed algorithm will be
analyzed using:
efficient modified Advanced Encryption Standard
adapted for image cryptography. This modified AES
encryption time. B.Subramanyam, Vivek Chhabria,
TG Shankar Babu[3] proposed AES with high
encryption quality and less computational time and to
make the key sensitivity of the algorithm resistant
Key Space Analysis  

Statistical Analysis  

Correlation Analysis  

Differential Analysis  

Key sensitivity Analysis  

proposes shift row adjustment in original AES, so as
to give better results in terms of security and




towards attacks. The technique in [4] is based on
Nearest Neighbouring Coupled Map Lattices (NCML)
Security analysis is the art of finding the weakness of
a cryptosystem and retrieval whole or a part of a
. Encryption in [5] uses multiple chaotic systems.
ciphered message (in this area, an image) or finding
Pankesh Bamotra[6] demonstrated the idea of
the secret key without knowing the decryption key or
encryption of grayscale images using pixel shuffling
the algorithm. There are many techniques for applying
method.[7] analyses two novel chaos based algorithms
analysis, depending on what access the analyst has to
and also discusses various parameters for comparison
the plaintext, ciphertext, or other aspects of the
of
cryptosystem,below are some of the most common
two
algorithms.
are:Number
of
Pixel
The
comparision
Change
criteria
Rate,Correleation
Coefficient, Entropy and Unified average changing
types of attacks to encrypted images:
A. Key Space Analysis
intensity.
Try to find the decryption key by checking all
3. Proposed Methodology
Proposed method aims at considering AES of 256 bit
block size of 128bits using 256-bit key size and
14rounds for RGB images. It aims at redefining the
conventional left shift operation by circular right shift
operation Among the
sequence of operations:
Substitution of bytes operation provides non-linearity
possible keys. The number of try to find directly refers
to key space of the cryptosystem grow exponentially
with increasing key size. It means that doubling the
key size for an algorithm does not simply double the
required number of operations, but rather squares
them.
An encryption algorithm with a 128 bit in key size
E. Key Sensitivity Analysis
defines a key space of 2128, which takes about 1021
In addition of large enough key space to resist a
years to check all the possible keys, with high
cryptosystem at brute force attack, also a secure
performance
a
algorithm should be completely sensitive to secret key
cryptosystem with key size of 128 bit computationally
which means that the encrypted image cannot be
looks robust against a brute force attack.
decrypted by slightly changes in secret key.
computers
of
nowadays.
So
B. Statistical Analysis
Statistical
analyzing
demonstrates
the
relation
References
between the original and encrypted image. Therefore,
encrypted image must be completely different from
1. M. Zeghid, M. Machhout, L. Khriji, A. Baganne,
the original. Due to Shannon theory [17] It is possible
and R. Tourki , World Academy of Science,
to solve many kinds of ciphers by statistical analysis.
Engineering and Technology International Journal of
For an image there are some ways to determine
Computer, Information, Systems and Control
whether the ciphered image leaks any information
Engineering Vol:1 No:3, 2007 “A Modified AES
Based Algorithm for Image Encryption”(2007)
about the original one or not.
C. Correlation Analysis
Two adjacent pixels in a plain image are strongly
[2] Abdulkarim Amer Shtewi, Bahaa Eldin M. Hasan,
correlated vertically and horizontally. This is the
property of an image, the maximum value of
Abd El Fatah .A. Hegazy, “An Efficeint Modified
Advanced Encryption Standard Adapted for Image
correlation coefficient is 1 and the minimum is 0, a
Cryptosystems”,
robust encrypted image to statistical attack should
IJCSNS, International Journal of Computer Science
and Network Security, VOL. 10 No.2, February 2010.
Pp. 226-232.
have a correlation coefficient value of 0.
D. Differential Analysis The aim of this experiment is
to determine the sensitivity of encryption algorithm to
slight changes. If an opponent can create a small
[3] B. Subramanyam , Vivek.M.Chhabria, T.G.
change (e.g. one pixel) in the plain image to observe
Shankar Babu, “Image Encryption Based on AES Key
Expansion”, 2011 Second International Conference on
the results, this manipulation should cause a
significant change in the encrypted image and the
opponent should not be able to find a meaningful
Emerging Applications of Information Technology,
pp.217-220.
relationship between the original and encrypted image
with respect
to diffusion and
confusion, the
[4] Yong Wanga, Kwok-Wo Wong, Xiaofeng Liaoc,
differential attack loses its efficiency and become
Guanrong Chen, “A new chaos-based fast image
useless.
encryption algorithm”, Applied Soft Computing,
Elsevier,2011.
[5] H.Alsafasfeh, and, A.A.Arfoa, Image encryption
based on the general approach for multiple chaotic
Software Engineering 2(12), December -2012, pp.
279-282.
system, Journal of Signal and Information Processing
2, 238-244, 2011.
[6] Pankesh Bamotra, International Journal of
Advanced Research in Computer Science and
[7] Lini Abraham, Neenu Daniel,Secure Image
Encryption Algorithms: A Review , International
Journal of Scientific & Technology Research
Volume2,Issue
4,April
2013.