Performance Analysis of Application for Security Enhancements using Cryptanalysis

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 04 Issue: 09 | Sep -2017 www.irjet.net p-ISSN: 2395-0072
© 2017, IRJET | Impact Factor value: 5.181 | ISO 9001:2008 Certified Journal | Page 1251
Performance Analysis of Application for Security Enhancements using
Cryptanalysis
Malvina Rumao1, Vikas Kaul2, Deven Shah3
1 P.G Student, Thakur College Of Engineering and Technology / Mumbai University, India
2 Assistant.Prof, Thakur College Of Engineering and Technology / Mumbai University, India
3 Professor, Thakur College Of Engineering and Technology / Mumbai University, India
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Abstract -With advent of new technologies, enormous
amount of applications flow through the internet making it
critical to handle the security aspects of data in the
applications.Advanced Encryption standards coupled with
many such security algorithms and its various versions are
used to increase confidentiality and provide integrity of data.
Also due to advancement in attacks, security algorithms have
become vulnerable to various kinds of cryptanalytic attacks.
The most important constituent of symmetric cryptosystem is
Substitution box as it enhances security of cryptography by
providing non-linearity.
Dynamic S-box is designed so that S-box is changed in every
round based on key and number of rounds by using RC4
algorithm, and complexity is enhanced by using round
structure thus increasing the level of difficulty for attacker.
Performance evaluation of the above system is done on
randomness test which includes strict avalanche criteria,
Differential approximation probability and linear
approximation probability. Cryptographic properties are
evaluated by using this software which will help to determine
the quality of S-box thus analyzing AES.
Key Words: Cryptography, AdvancedEncryptionStandard,
Strict Avalanche Criteria, Linear Cryptanalysis, Differential
Cryptanalysis
1. INTRODUCTION
Important concern in developing efficient communication is
providing Data security. Effective method of cryptography is
adopted to solve this issue effectively to provide integrity,
availability, authentication, privacy, accuracy and
computability. Cryptography means secret writing which
uniquely define the mathematical steps required to encrypt
and decrypt messages in a cryptographic system, thus
protecting data from unauthorized access [1].The
mathematical procedure of encipherment enriches
cryptographic products, e-trading, e-banking, e-commerce
and electronic signatures for secure transactions.
Encipherment processtransformsplaintexttothescrambled
cipher text To offer secure transmission and storage of
information/data, many symmetric algorithms were
proposed such as Data Encryption Standard (DES), the
Elliptic Curve Cryptography (ECC), Rijndael Algorithm and
etc. Cryptography is science of encryption and decryption of
confidential and often sensitive messages [3]. The Advanced
Encryption Standard algorithm (AES) has been defined by
National Institute of Standards and technology of United
States as a new private key decryption algorithm. AES
algorithm on the basis of attributes: encipherment and
decipherment and degree of security issues essential forsafe
wired and wireless communication [4]
1.1 Advanced Encryption Standard
The Advanced Encryption Standard(AES) was designed
because DES’s key was too small and triple DES was a slow
process. The National Institute of Standard and
Technology(NIST) chose the Rijndael algorithm named after
its Belgian Inventors, Vincent Rijmen and Joan Daemen. AES
is very complex round cipher. Number of rounds in AES
depends on Key size: keysizeof 128 bits-numberofroundsis
10, key size of 192 bits-number of rounds is 12, key size of
256 bits-number of rounds is 14. An Encryption system
contains set of transformation that converts plain text to
cipher text, these set of transformation are Shift row
transformation, Mix column transformation, Add round key
and sub-byte transformation. Fault attacks on AES can be
classified into two categories depending on fault location:
fault attack on key schedule and fault attack on encryption
process.
1.2 AES S-Box
Same S-box used in every round is being referred to as
Static S-box while key dependent S-box means that S-box
changes in every round depending on the number of keys
and number of rounds. By making S-box key dependent we
assume S-box will be strong. The round key generated will
be used for finding a value that is use to rotate S-box[5].
1.3 RC4
A algorithm designed by Rivest for RSA data security
named RC4 is a variable key-size stream cipher with byte
oriented operations. This algorithm is used for random
permutation.RC4 is file encryption algorithm to establish
secure communication[6].

2. Literature Review
The below literaturesurvey analyzes the work donebyarray
of researchers and scholars in field of data and network
security. The technical papers stated below gives the idea of
performing analysis of application for security enhancement
using cryptanalysis.
In paper [1], authors Nan Lio, Xiaoxin Cui, Tang Wang, Kai
Liao and Dunshan Yu have proposed a method to overcome
faults in S-box by proposing Fault model based on S-box
faults in encryption process. Two models have been
proposed aiming at S-box faults in round10throundand9th
round encryption process
In paper [2], the authors Shivlal Mewada, Pradeep Sharma,
S.S Gautam explores efficientprivatekeyalgorithm basedon
security of individual system and to improve encipherment
and Decipherment time with encipherment/Decipherment
performance.
In paper[3],Ashwak Alabaichi, Adnan Ibrahem Salih,
discusses the enhancement of the AES algorithm and
describes the process, which involves the generation of
dynamic S-boxes for Advance Encryption Standard(AES)
values of correlation confection for dynamic AES and AES
In paper[4], authors Julia Juremi, Ramlan Mahmod, Salasiah
Sulaiman state that the original S-box consists of 4 stages
while in this new design, it consists of five stages, the extra
stage is known as S-box rotation and it is introduced at
beginning of round function. It shows very strong resistance
against linear cryptanalysis and differential cryptanalysis.
In paper [5],authors summarize YongWang,QingXie,Yuntao
Wu, Bing Du, the performance index and are analyzed.
Software fortesting performance index ofS-boxisdeveloped
through which evaluation is done to find high cryptographic
performance.
In paper [6],authors Ripal Patel and Vikas Kaul have
enhanced AES using RC4 algorithm to create dynamic s-box
and key scheduling algorithm to increase its complexity.
3. Proposed System
Security of whole cryptography system is based of security
of S-box. Evaluation of security of S-box and design issues in
S-box is still of concern in block cipher. Static S-box are
vulnerable to various typesofattacks,sobyusingdynamicS-
box it is difficult for attackers to do any offlineinterpretation
of particular set of S-box. The goal of this project is to
evaluate the effect of dynamic S-box on security of AES.
These S-boxes can be created when they are required and
thus reduce the need of storing large data structures within
algorithm. Performance indexes will help indeterminingthe
cryptanalysis of the generated S-box so that it can be
evaluated for its security enhancement. System canbemade
more complex by using AES round structure. SHA-256 isuse
to provide integrity of data and RSA is used as key exchange
algorithm. Performance evaluation of the above system is
based on randomness test which includes Strict avalanche
criteria, Differential approximation probability and Linear
approximation probability.
Fig 1: Proposed System
4 . Design Methodology
The proposed dynamic S-box has the same block length and
key length as the original AES. It has block length which is
128 bits and three key lengths which are 128, 192, and 256
bits. The dynamic AES includes two processes, which are
encryption and decryption. These processes resemble the
original AES with an additional step that is introduced at the
start of the round function. This step is called S-box
Permutation, below figure illustrate the proposed dynamic
AES. It is noticed that the last four stages are the same as
those in the AES[1].

Fig 2: AES Dynamic S-box
The Key expansion transformation takes key and generates
expanded key and output of key pseudo expansionalgorithm
i.e expanded key is used to generate S-box by RC4 key
schedule algorithm to prevent repetitions.
To increase complexity, round structure is used which takes
input of 256 bits which is divided in two blocks of 128 bits
each. One block of 128 bits is given as input to AES section of
system and other block of 128 bits is given to AES section of
system in next round as perstructure.Processiscontinuedas
per the rounds suggested. The output is constructed by
combining all the data together.
Fig 3: AES in Round Structure
Performance Evaluation:
1. Strict Avalanche Criteria:
In Strict avalanche criteria we look at each bit one by one
and verify that whatever the other bits will change it will
have a 50% probability to switch. Each bit should have 50%
chances to change if you change 1 bit of input. It is satisfiedif,
whenever a single input bit is complemented each of its bits
changes with a 50% probability. Strict avalanche criteria
consists of absolute indicator and sum of square indicator. It
is calculated by stating absolute indicator value and value of
sum of square indicator.
2. Linear Approximation Probability.
Highprobabilityoccurrenceoflinearexpressioninvolving
plaintext bits and cipher text bits. The resistance of S-box to
Linearcryptanalysis is closely related toco-efficientofWalsh
Hadamard Transform of all non-zero linear combination of
relevant component function, it is use to calculate
nonlinearity, bigger the nonlinearity unsuccessful is the
attack. Linear Cryptanalysis is to find an approximate of
relationship between plain text, cipher text and key, i.e
presenting linear dependence involving three parties.
3. Differential approximation Probability.
The differential approximation probability is based on
analysis of effect of particulardifferences in plain text andon
the differences of resultant cipher text pairs. These
differences are use to assign probabilities to possible keys in
cipher text and locate the most probable key. If differential
delta uniformity(DDT) is flatter than the probabilities for
distinct differences are similar and no information can be
extracted. The attacker computes the differences of
corresponding cipher text hoping to detectstatisticalpattern
in their distribution with help of XOR operation, one
particular cipher text difference is expected to be especially
frequent in thiswayciphercanbedistinguishedfromrandom
text.
5 . Results
File: “plaintext.txt”, Size: 144 bytes (1552 bits), Key:
12345678901234561234567890123456

Table -1: Encryption time and Decryption time is
recorded using text file as input on Microsoft Windows 10,
Intel i3, 64 bit, 6 GB RAM
Sr. Algorithm Block
No size
Enc
ryp
tion
Decrypti
on
Ti
me
(Se
c)
Time(S
ec)
i3 i3
1
AES 128
0.003230.00252
2 Enhanced
128
0.00291
AES
0.00348
3 Round
0.00317
Structure 256
0.00275(1R)
4 Round
0.00359
structure
with
256
Enhanced 0.00299
AES(1R)
5 Round
0.00290 0.00337
structure
(5R)
256
6 Round
structure
with
256
0.00337 0.00435
Enhanced
AES(5R)
7
Round
Structure
(10R) 256
0.00356
0.00328
3
8
Round
structure
with
Enhanced
AES
(10R) 256 0.00389 0.00480
Fig 4: Graphical Representation for encryption time and
decryption time for text input
File: “img.png”, Size: 144 bytes (1552 bits), Key:
12345678901234561234567890123456
Table -2: Encryption time and Decryption time is
recorded using image file as input on Microsoft Windows
10,Intel i3, 64 bit, 6 GB RAM
.Sr. Algorithm Block
No size
Enc
ryp
tio
n
Decryp
tion
Ti
me
(Se
c)
Time(S
ec)
i3 i3
1
AES 128 0.02332
0.02378
2 Enhanced
128
0.02502
AES
0.03160
3 Round
0.01687
Structure 256
0.01653(1R)
4 Round
structure
with
256
Enhanced
0.0176AES(1R)
0.01644
3
5 Round 0.05820 0.061371

structure
with
256
Enhanced
AES(5R)
6 Round
structure
with
256
0.0595 0.06323
Enhanced
AES(5R)
7
Round
Structure
(10R) 256
0.133080.11268
8
Round
structure
with
Enhanced
AES (10R) 256 0.11386 0.11932
Fig 5: Graphical Representation for encryption time and
decryption time for image input
Performance Analysis is done by using strict avalanche
criteria, Linear approximation probability and Differential
approximation probability. Strict Avalanche criteria is
calculated using absolute indicator and sum of square of
indicator. The smaller is the value of absolute indicator and
sum of square indicator the better is Strictavalanchecriteria.
Linear approximation probability is obtained by calculating
Nonlinearity, greaterthevalueofnonlinearityunsuccessfulis
the attack. Differential approximation probability is
robustness to differential cryptography, hence the value
should be high for ideal AES. S-box of Traditional AES and
Enhanced AES is given as input and values for nonlinearity,
Differentialapproximationprobabilityandabsoluteindicator
and sum of square of Indicator are obtained.
Table -3: Performance analysis of Traditional AES and
Enhanced AES using RC4
6 . Conclusion
Security is key aspect of communication, encryption of
information makes it inaccessibletounauthorizedrecipients.
One of the most secure encryption algorithm is AES
encryption. Due to increasing use of technology and large
amount of data being transferred with not enough security
this sensitive data becomes vulnerable to different attacks.
Main reasons or vulnerability of AES encryption algorithm is
use of static S-boxes. This project proposesamethodtomake
S-box dynamic so that its structure is hidden from
cryptanalyst making it difficult for attackers to attack and
thus making it resistant to differential and linear
cryptanalysis. Performance Index such as Strict avalanche
criteria, Differential approximation probability and Linear
approximation probability are used to evaluate the
performance of AES. It is observed that Enhanced AES with
dynamic RC4 resists to linear and differential cryptanalysis
and also its Encryption and Decryption time has been
recorded using various versions of AES algorithm.
REFERENCES
[1] Nan Liao, Xiaoxin Cui, TiangWang,Kai Liao,
DunshanYu“A high- efficient fault attack on AES S-box”.
[2] ShivlalMewada, Pradeep Sharma, S. S.
Gautam,“Exploration of Efficient Symmetric AES
Algorithm “,2016 Symposium on Colossal Data Analysis
and Networking (CDAN).
Sr.N
o
Algorit
hm
Strict Avalanche
Criteria
Non
line
arit
y
Differe
ntial
Approx
imatio
n
Probab
ility
1 AES
32, 133120
(Absolute
indicator:32, Sum
of Square of
Indicator:133120)
112.
000
0 0.98
2
Enhanc
ed AES
with
dynami
c S-box
using
RC4
96,283648
(Absolute
indicator:96,
Sum of Square of
Indicator:283648)
94.0
000 0.96

[3] Ashwakalabaichi, Adnan IbrahemSalih, “Enhance
Security of Advance EncryptionStandard Algorithm
Based on Key-dependent SBox”, ISBN: 978-1-4673-
6832-2©2015 IEEE
[4] Julia Juremi, RamlanMahmod, SalasiahSulaiman.” A
Proposal for Improving AES S-box with Rotation and
Key- Dependent”
[5] Yong Wang, Qing Xie, Yuntao Wu, Bing Du, “A Software
for S-box Performance Analysis and Test”, 2009
International Conference on Electronic Commerce and
Business Intelligence
[6] Ripal Patel, Vikas Kaul,” Security Enhancement in Next
Generation network using Enhanced AES with RC4 and
dynamic S-box”, 2017 Internation Research Journal of
engineering and Technology.
[7] Farshid Hossein Nejad, Saman Sabah, Amid Jamshidi
Jam,” Analysis of Avalanche Effect on Advance
Encryption Standard by Using Dynamic S-Box Depends
on Rounds Keys. “,International Conference on
Computational Science and Technology – 2014
(ICCST’14)
[8] Abhiram.L.S, Gowrav.L, PunithKumar.H.L “Design and
synthesis of Dual Key based AES Encryption”, MSRIT,
BANGALORE, India, 21-22 NOVEMBER 2014.
[9] Thomas Fuhr, Eliane Jaulmes, Victor Lomne and Adrian
Thillard “Fault Attacks on AES with faulty Ciphertexts
Only” , 2013 Workshop on Fault Diagnosis and
Tolerance in Cryptography.
[10] Howard M.Heys,”A Tutorial on Linear and Differential
Cryptanalysis”.

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