Android based message encryption decryption using matrix

IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
_______________________________________________________________________________________
Volume: 04 Issue: 01 | Jan-2015, Available @ http://www.ijret.org 315
ANDROID BASED MESSAGE ENCRYPTION/DECRYPTION USING
MATRIX
Dinesh P. Baviskar1
, Sidhhant N. Patil2
, Onkar K. Pawar3
1
Technical Assistant, Computer Department, Ahinsa Polytechnic Dondaicha, Dhule (425408)
2
HOD, Electrical Department, Ahinsa Polytechnic Dondaicha, Dhule (425408)
3
Computer Department, Ahinsa Polytechnic Dondaicha, Dhule (425408)
Abstract
In this paper we are going to encrypt plain text to encrypted text. Message encryption is character value based encryption in
which 3D message character matrix is replaced with 2D encryption value matrix. It can also know by some kind of message
masking which work on upper level to provide maximum security. Password protection increases encrypted message file security.
Keywords – Matrix, ASCII Offset Value, DES, 3D Message Masking, and 2D.
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1. INTRODUCTION
Now a days Android mobiles are becoming popular
everywhere. Anyone with few bucks can brought android
mobile, also Akash Tablet for students work on Android OS.
Android is Open Source Platform so anyone can develop
apps for Android platform also changes can made in
Android OS. Android provide lot of programming power
with Linux kernel.
Various apps are present in Android Market for text
communication. Communication is required to complete
your work efficiently. But security is must in
communication. Due to open source security of android
platform is less. So it is possible to find vulnerability of
Android OS to use it for hacking purpose.
This android application is developed to provide security to
text communication between Android devices using
MATRIX encryption.
We developed MATRIX encryption technique to provide
maximum security on ASCII level with less computing to
work on low resource configuration android mobiles also.
1.1 Overview
Today data theft becoming very dangerous. We know words
are dangerous than any other weapon. But weapon in wrong
person’s hands is most hazardous.
If sensitive information like atomic bomb is hacked by
terrorists then they can use that info to create atomic bomb
against us. Android is powerful but less secure cause of
Open Source. So we need to provide security to your data in
android device like SMS, files, Emails.
Everyone wants to keep his messages and files secret and if
you find your messages? It will very bad for you. This can
happen with your Android device. Many applications found
in Android market which theft your data, messages, emails
and lot more from your android mobile.
If we can’t save data from steal then we need to convert it as
it will no longer use by hacker. This can achieve by
encryption. Current encryption techniques are good but they
are developed for computers which have large processing
power, memory but there is no special technique for android
device. Android devices low processing power and memory
so we need to optimize encryption technique for android like
Delvik Virtual Machine.
This MATRIX encryption technique is fully developed and
optimized for android devices. So it can use on android
mobile efficiently.
2. EXITING SYSTEM & PROBLEM
DEFINITION
DES algorithm and Six ways to break DES
DES (Data Encryption Standard) is a symmetric
cryptographic algorithm which was adopted in January 1977
as a standard (see [1]) for protecting non-classified
information in the United States by the former National
Bureau of Standards (now known as National Institute of
Standards and Technology). It is widely used for protecting
sensitive information and for the authentication of banking
transactions, for example. We propose here to present six
different ways to break DES, the last one being currently
analysed at the LASEC.
2.1 Exhaustive Key Search
DES is an algorithm which encrypts 64 bits blocks of data
using a 56 bits secret key. A common scenario is the
following: we have an encrypted block at disposal, we have
some information about the plaintext (we know that it is an
ASCII text, or a JPEG image, for example) and we would
like to recover the secret key.

_______________________________________________________________________________________
The simpler method is to try to decrypt the block with all the
possible keys. The information we have on the clear text
will allow us to recognize the right key and to stop the
search. In average, we will have to try
36'028'797'018'963'968 (36 millions of billions) of keys.
Knowing that a common modern PC can check about one to
two millions keys each second, this represents a work time
of about 600 to 1200 years for a single machine.
2.2 A Dedicated Machine
An exhaustive search is quite time consuming for a single
PC, but it is possible to do better. In 1998, the EFF
(Electronic Frontier Foundation has built a dedicated
machine ([10]) in order to show to the world that DES is not
(or no more) a secure algorithm. Deep Crack, that's the
name of the machine, costs $200'000 and is built with 1536
dedicated chips. Deep Crack is able to recover a key with
the help of an exhaustive search in 4 days in average,
checking 92 billion of keys each second. Knowing the
budget of electronic intelligence agencies (for example, the
National Security Agency in the USA), it is easy to be
pessimistic on the security of DES against such
organizations!
2.3 A Huge Cluster of Computers
One needs not even a lot of money to break DES.
Volunteers who are ready to donate their machine's idle time
and the Internet are sufficient. In January 1999,
Distributed.Net, an organization specialized in collecting
and managing computer's idle time, broke a DES key in 23
hours! More than 100'000 computers (from the slowest PC
to the most powerful multiprocessors machines) have
received and done a little part of the work; this allowed a
rate of 250'000'000'000 keys being checked every second.
2.4 A Time-Memory Tradeoff
An exhaustive search needs a lot of time, but negligible
memory at all. It is now possible to imagine an scenario: we
have a lot of available memory, and we are ready to
precompute for all the possible keys k the encrypted block y
corresponding to a given block x of data and storing the
pairs (y, k) . So we will be able to find very quickly the right
key if we have at disposal an encrypted version x' of our
known block with an unknown key k' by searching in this
kind of dictionary. This method becomes to be interesting in
the case where we have more than one key to find and we
have enough memory at disposal.
In 1980, Martin Hellman proposed in [2] a time-memory
tradeoff algorithm, which needs less time than an exhaustive
search and less memory than the storing method. His
algorithm needs in the order of 1000 GB of storage
possibilities and about 5 days of computations for a single
PC.
2.5 Differential Cryptanalysis
In 1990, Biham and Shamir, two Israeli cryptographers
working at the Weitzmann Institute, have invented (see [3])
a new generic technique to break symmetric algorithms
called the differential cryptanalysis. It was the first time that
a method could break DES in less time than an exhaustive
search.
Imagine that we have a device which encrypts data with a
hard-wired secret key, and imagine furthermore that we
don't have the tools needed to "read" the key in the chip.
What we can do is to choose some blocks of data and to
encrypt them with the device.
The data analysis phase computes the key by analyzing
about 247
chosen plaintexts. A big advantage of this attack is
that its probability of success increases linearly with the
number of available chosen plaintexts and can thus be
conducted even with fewer chosen plaintexts. More
precisely, the attack analyses about 214
chosen plaintexts and
succeeds with a probability of 2-33
.
2.6 Linear Cryptanalysis
Another very important generic method to break ciphers is
the linear cryptanalysis ([4]), which was invented in 1994 by
a Japanese researcher working at Mitsubishi Electronics,
Mitsuru Matsui. If we have 243
= 8'796'093'022'208 known
plaintext-cipher text pairs at disposal, which represents
64'000 GB of data, it is possible to recover the
corresponding key in a few days using linear cryptanalysis.
It is the most powerful attack on DES known at this time.
A current research project at the LASEC is the cost analysis
of this attack. We have first implemented a very fast DES
encryption routine using advanced techniques on a common
Intel Pentium III architecture; this routine is able to encrypt
at a rate of 192 Mbps on a PIII 666MHz processor. We have
then implemented the attack; it is currently running on 18
CPU's, breaking a DES key in 4 days.
The goal of this project is to do a better statistical analysis
on its complexity and on its success probability. First
experimental and theorical results have shown that a linear
cryptanalysis needs in reality less time as estimated by
Matsui in 1994.
2.7 Conclusion from Existing System
There is no special encryption technique for android
platform. Existing some encryption techniques are good in
security but very costly in resource requirement and some
encryption techniques are not costly in resource requirement
but they are not secure
If we use costly encryption technique then application may
freeze in low configuration android mobiles this will make
negative impact on users.
But we can’t use other encryption technique for security
reason so there should be an optimized technique which
provide maximum security and requires less resource.

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2.8 Project Plans
Our Plan is To Develop an encryption technique for android
devices. These Themes We Will Be Implementing in project
 Encrypt text files and text message on android
device using MATRIX technique.
 Internet communication
 Encrypt GTalk text communication using MATRIX.
Proposed System
This MATRIX encryption algorithm is developed specially
for android devices. It can use with very low configuration
android devices also. It is secure also; MATRIX is used to
achieve dynamic encryption values with change in location
of characters.
This algorithm uses only 8-10 % cpu for encryption and
only 5% for decryption. These are very less numbers than
other algorithm. Also it is very secure as third person
doesn’t know size of MATRIX then it became very difficult
to crack message and total no of possibilities to generate
MATRIX values are 3.2e+660
Above value is very big to crack message and it is useless if
you don’t know MATRIX size so this encryption algorithm
is very hard to crack.
That means it can encrypt message using low computing
without compromising with security.
3. SYSTEM IMPLEATATION
3.1 Matrix Encryption
Message Matrix
In this project we are going to encrypt plain text to
encrypted text. Message encryption is character value based
encryption in which 3D message character matrix is
replaced with 2D encryption value matrix. It can also know
by some kind of message masking which work on upper
level to provide maximum security. Password protection
increases encrypted message file security.
• Encryption Values:- These encryption matrixes
contain encrypted values.
• Unique Matrix:- Every character has unique
matrix.
• Dynamic Values:- Encryption value changes with
change in location.
* % # @
! ` { ;
“ . / &
This MATRIX algorithm is developed to encrypt only text
data. Currently encryption MATRIX is created for 99 most
commonly used characters. We can increase number of
characters.
Features of MATRIX:-
1. Protection from brute force attack and dictionary attack.
2. MATRIX size is automatically generated.
3. It can detect message is encrypted or not for GTalk or
other chatting.
In above we can see working of MATRIX encryption.
It is as follows:
1. At first message is converted into 3D MATRIX.
2. Then MATRIX containing encryption values for each
character are generated.
3. Characters from Message matrix are replaced using
encryption values of proper characters and location.
4. This encrypted message is stored in .o2k file with other
information which is required to decrypt message.
In above example we can see a simple example of MATRIX
encryption with feature of dynamic values.
Matrix encryption is works on overlapped matrix for every
character.
Starting value of each matrix is greater than previous matrix
by one value.

_______________________________________________________________________________________
A: [ID=0]
1 2 3 4 5 6 7 8 Encryption Value
0 1 2 3 4 5 6 7 Location Index
B: [ID=1]
C: [ID=2]
Sample:
Take a message “ABBCAAABABB”
Length of message= 11
For this encryption we will consider above encryption
matrix of character A,B and C.
Matrix size is 8
Formula:
1. For Encryption:
Encryption value=(ID+Base Encryption Value)+Location
Index
2. for Decryption:
ID=(Encryption value- Location Index)-Base Encryption
Value
For First Letter from message ( Letter is ‘A’)
Encryption Value=( 0 + 1) + 0 = 1 i.e. ID = 0, Base
Encryption Value = 1 and Location Index = 0
For second Letter from message( Letter is ‘B’)
For third Letter from message ( Letter is ‘B’)
For fourth Letter from message ( Letter is ‘C’)
Encryption Value=(2 + 1) + 3 = 6 i.e. ID = 2, Base
For fifth Letter from message ( Letter is ‘A’)
For sixth Letter from message ( Letter is ‘A’)
For 7th Letter from message ( Letter is ‘A’)
For 8th Letter from message ( Letter is ‘B’)
For 9th Letter from message ( Letter is ‘A’)
Encryption Value=( 0 + 1) + ? = ?i.e. ID = 0, Base
As matrix size is of 8 values, the range of Location Index is
from 0 to 7 only.
If Location Index becomes greater than 7 then it again get
initialized to zero value.
So Encryption value becomes
So Encrypted Message becomes.
Origial
Message
A B B C A A A B A B B
Encrypted
Message
1 3 4 6 5 6 7 9 1 3 4
For Decryption:
ID = (Encryption value- Location Index)-Base Encryption
Value
For 1st
Value: ‘1’
ID = ( 1 – 0) – 1 = 0 i.e. Encryption value= 1, Location
Index= 0 and Base Encryption Value =1
For 2nd
Value: ‘3’
For 3rd
Value: ‘4’
For 4th
Value: ‘6’

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For 5th
Value: ‘5’
For 6th
Value: ‘6’
ID = ( 6– 5) – 1 = 0 i.e. Encryption value= 6, Location
For 7th
Value: ‘7’
For 8th
Value: ‘9’
For 9th
Value: ‘1’
Here Location Index was greater than 7, So it is again set to
zero.
For 10th
Value: ‘3’
Index=1 and Base Encryption Value =1
For 11th
Value: ‘4’
Index=2 and Base Encryption Value =1
So Decrypted becomes.
Encrypted
Message
1 3 4 6 5 6 7 9 1 3 4
Decrypted
ID
0 1 1 2 0 0 0 1 0 1 1
Second Phase of Decryption:
Now convert Decrypted ID into Original Characters.
So Decrypted becomes.
Decrypted
ID
0 1 1 2 0 0 0 1 0 1 1
Original
Characters
A B B C A A A B A B B
So Message Becomes “ABBCAAABABB”
Which is exact same as original message.
This Second Phase of Decryption provides additional
security to encrypted message.
We can reorder all alphabets and numbers also symbols in
any order to generate ID for each character.
This ID is only known to sender and receiver so if anyone
tries to decrypt message using formula, that person will
stuck at second phase of decryption without knowledge of
ID.
Also overlapped matrix size can be modified. It makes to
crack message even more difficult, as the matrix is
overlapped so is difficult to guess when first matrix ends
and another starts.
That directly effects on ID and creates wrong decryption.
4. ANALYSIS
 Feasibility Study:
Feasibility Study is conducted to see if the proposed
system is a feasible one with all respects. Feasibility
Study is lot of the system proposal according to its
workability impact of the organization, ability to meet
uses need and effective use of resources. There are
three main aspects in the feasibility study. The
feasibility of a project can be ascertained in terms of
technical factors, economic factors, or both. A
feasibility study is documented with a report showing
all the ramifications of the project. In project finance,
the pre-financing work is to make sure there is no
"dry rot" in the project and to identify project risks
ensuring they can be mitigated and managed in
addition to ascertaining "debt service" capability.
 Economic Feasibility:
In economic feasibility cost/benefit analysis is done.
Here we determine the benefits and time savings that
are expected from the system and compare them with
cost. The proposed system is economically feasible.
We developed java package having classes and
methods for MATRIX encryption and decryption so
it will very easy and less costly to implement in
another application. Since the cost of the system is
only the implementation cost of the system. There is
no need spend any monthly thereafter. Since benefits
outweigh the cost. It is economically feasible.
 Operational Feasibility:
An operationally feasible system is one that will be
used effectively after it has been developed. If users
have difficulty with a new system, it will not produce
the expected benefits. The proposed system is found
to be operationally feasible because of the following
reasons. It is very simple in use. There is no difficulty
in using the front end which has been developed.
Even the users who don’t have any knowledge in
android mobile the user friendliness and help section
provides them convenience and case. The system is
designed, in such a way that not only the person
currently handling this work can operate the system
but a person who is new to the system with case.
Hence this system is found to be operationally
feasible.

_______________________________________________________________________________________
 Technical Feasibility:
Technical feasibility centers on the existing system
and to the extent it can support the proposed system.
This encryption package and application is built in
java language so they are platform independent. This
encryption can done on computer also using this
package. Hence this system is found to be technical
feasible.
 Market Feasibility:
This is a generalized project so that it can be used in
any application and service like SMS, Emails, GTalk,
Facebook, Twitter etc. The existing traditional system
is not optimized for android devices. Proposed system
use less computing resources efficiently and do not
compromise with security. So new system is not
costly and provides better security.
4. SYSTEM REQUIRMENT AND SPECIATION
4.1 Requirements to Develop/Run Android
Application on PC:-
Hardware Requirements
 Minimum 1Gb RAM,
 Minimum 20 GB HDD
 Dual Core processor or above
Software requirements
 Eclipse
 JDK compiler 1.5 and above
 SDK manager Revision 21
 ADT 21.0.0
 At least one Android Platform Package (prefer API
10)
4.2 Requirements to Run Android Application on
Mobile:-
 600MHz processor
 128 MB RAM
 Android-2.3 and above OS on Mobile/Simulator
 Minimum API Level 10
 525 KB memory on SD card or phone memory.
 At least Medium Screen Density Mobile
4.3 Connectivity Requirements:-
 In order to use encrypted message service over
internet your mobile/emulator (PC) must connected to
internet.
 To use GTalk chat service you must have your own
account on that service.
5. CONCLUSION
The Security of conversion on social website and data
sending becomes major issue especially in case of Google.
This paper present to protect conversion on social website
and data sending to provide security to generate key for this
purpose. In the proposed scheme data encryption algorithm
is used and also 3 D MATRIXES are used.This technique is
based on dynamic values for a character so it becomes very
difficult to identify actual message.
6. FUTURE DEVELOPMENT
 Emails, Facebook communication, Gtalk messages
and for all text messaging services this encryption
technique can provide private protection to your
messages.
 We can increase security by arranging blocks of
message in different ways.
 Word document, PDF files encryption support can
provide in future.
REFERENCES
[1]. Information Security,
http://www.infosec.gov.hk/english/technical/ files/ short.pdf.
[2]. Micro System Center, http://technet.microsoft.com/en-
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Secure SMS Messaging Protocol for the M-Payment
Systems, IEEE Symposium on
Computers and Communications, 2012, 700-705.
[4]. Marko Hassinen, SafeSMS - End-to-End Encryption for
SMS Messages, IEEE International Conference on
Telecommunications, 2008,
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Newaz, A Proposal for Enhancing the Security System of
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[7]. Na Qi Jing Pan Qun Ding, The Implementation of
FPGA-based RSA Public-Key Algorithm and Its
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Encryption System, IEEE International Conference on
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700-703.
[8]. Ch. Rupa and P.S. Avadhani, Message Encryption
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[9]. Rishav Ray, JeeyanSanyal, Tripti Das,
KaushikGoswami, Sankar Das and AsokeNath, A new
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Android based message encryption decryption using matrix

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