Data Security on Computer Network and Telecommunication System Using Caesar Cipher Cryptography Algorithm: A Java Implementation

International Journal of Engineering and Advanced Technology (IJEAT)

ISSN: 2249 – 8958, Volume-4, Issue-4,

1

Published By: Blue Eyes Intelligence Engineering & Sciences Publication Pvt. Ltd.

Abstract— In this era of global communication where online

communication through the use of computer network and

telecommunication system has dominated the means of

communication between people. The goal of privacy is very

paramount. The numbers of people being connected to the

communication system through their mobile phone, computer or

any other e-communication tools are increasing day-by-day.

Hence there is need to secure the communication networks from

adversaries (third parties) between the sender and receivers.

There are many aspects to security approach in data

communication environment. One essential aspect for secure

communications is that of cryptography, which the focus of this

research is. We have developed stand-alone application software

that implements cryptography using Caesar algorithms. This

program can be implemented with chatting software or E-mail

software to encrypt data. The algorithm was coded with Java

programming language.

Index Terms— Caesar Cipher, Cryptography, Java

programming language, Computer network

I. INTRODUCTION

The goal of privacy is achieved if a message is only

received by the intended recipients. This goal is normally

accomplished using encryption algorithms. Encryption

algorithms convert the original message, called the plaintext,

into an encrypted form called the ciphertext that must be

decrypted back into the plaintext by the recipient in order for

it to be meaningful.

Most ciphers use a piece of information called a key for

encryption and decryption, and ciphers that use the same key

for both processes (sender and recipient) are called

symmetric key ciphers, as opposed to asymmetric key ciphers,

in which the keys are different on both sides of the message

transmission channel [1].

Cryptography is the science of writing in secret code and is

an ancient art; the first documented use of cryptography in

writing dates back to circa 1900 B.C. when an Egyptian

scribe used non-standard hieroglyphs in an inscription. Some

experts argue that cryptography appeared spontaneously

sometime after writing was invented, with applications

ranging from diplomatic missives to war-time battle plans. It

is no surprise, then, that new forms of cryptography came

soon after the widespread development of computer

communications [2].

In cryptography, a Caesar cipher is one of the simplest and

most widely known encryption techniques. It is a type of

substitution cipher in which each letter in the plaintext is

replaced by a letter some fixed number of positions down the

alphabet. For example, with a shift of 3, A would be replaced

by D, B would become E, and so on. The method is named

after Julius Caesar, who used it in his private correspondence

[3]. The focus of this paper is to design and implement a

caser cipher application system that can protect data from

theft or alteration, and also be used for user authentication

when communicating over any untrusted medium, which

includes just about any network, particularly the Internet.

In Caesar Cipher the transformation can be represented by

aligning two alphabets; the cipher alphabet is the plain

alphabet rotated left or right by some number of positions.

For instance, here is a Caesar cipher using a left rotation of

three places (the shift parameter, here 3, is used as the key):

Plain: ABCDEFGHIJKLMNOPQRSTUVWXYZ Cipher:

DEFGHIJKLMNOPQRSTUVWXYZABC. When

encrypting, a person looks up each letter of the message in

the "plain" line and writes down the corresponding letter in

the "cipher" line. Deciphering is done in reverse [4]. The

diagram below illustrates a typical Caesar Cipher. The

Caesar Cipher is an encoding method that works like this;

this example is for a shift amount of 13, which is a ROT-13.

if (character is in alphabet)

{

if(character is in bottom half of alphabet [A-M|a-m] )

character = character + 13;

else /* character is in top half [N-Z|n-z] */

character = character – 13;

}

print(character);

In a Caesar cipher, each letter is replaced by a letter further

along in the alphabet. You can think of it as shifting the

alphabet to the left. The key of a Caesar cipher is the number

of places the alphabet is shifted. Here is a Caesar cipher with

key 3:

A. Objectives of This Research Work

The objectives of this research work are to:

To achieve the goal of privacy in data communication

and telecommunication system i.e. a message is

only received and decoded by the intended

recipients.

To provide confidentiality, authenticity, integrity,

and non-repudiation of the information transmitted

through the online

Data Security on Computer Network and

Telecommunication System Using Caesar Cipher

Cryptography Algorithm: A Java Implementation

Akinyele A. Okedola, Yekini N. Asafe

Data Security on Computer Network and Telecommunication System Using Caesar Cipher Cryptography Algorithm:

A Java Implementation

2


communication network.

To develop a cryptographic algorithm that is an

improvement on the existing system

B. Scope of Study

This research work focuses on design and implementation

of cryptosystems for preventing third parties from assessing

data/information (message) between sender and receiver on

online communication using caesar algorithm with java

programming language.

II. LITERATURE REVIEW

A. Cryptograph Concept and Data Communication

In data and telecommunications, cryptography is

necessary when communicating over any untrusted

medium, which includes just about any network,

particularly the Internet. Within the context of any

application-to-application communication, there are some

specific security requirements, including:

Authentication: The process of proving one's identity.

(The primary forms of host-to-host authentication

on the Internet today are name-based or

address-based, both of which are notoriously weak.)

Privacy/confidentiality: Ensuring that no one can

read the message except the intended receiver.

Integrity: Assuring the receiver that the received

message has not been altered in any way from the

original.

Non-repudiation: A mechanism to prove that the

sender really sent this message.

Cryptography, then, not only protects data from theft or

alteration, but can also be used for user authentication.

There are, in general, three types of cryptographic schemes

typically used to accomplish these goals: secret key (or

symmetric) cryptography, public-key (or asymmetric)

cryptography, and hash functions, each of which is

described below. In all cases, the initial unencrypted data is

referred to as plaintext. It is encrypted into Cipher text,

which will in turn (usually) be decrypted into usable

plaintext [4].

B. History and usage Caesar Cipher

The Caesar cipher is named after Julius Caesar, who,

according to Suetonius, used it with a shift of three to protect

messages of military significance. While Caesar's was the

first recorded use of this scheme, other substitution ciphers

are known to have been used earlier.

If he had anything confidential to say, he wrote it in

cipher, that is, by so changing the order of the letters of the

alphabet, that not a word could be made out. If anyone wishes

to decipher these, and get at their meaning, he must

substitute the fourth letter of the alphabet, namely D, for A,

and so with the others.

It is unknown how effective the Caesar cipher was at the

time, but it is likely to have been reasonably secure, not least

because most of Caesar's enemies would have been illiterate

and others would have assumed that the messages were

written in an unknown foreign language.[4] There is no

record at that time of any techniques for the solution of

simple substitution ciphers. The earliest surviving records

date to the 9th century works of Al-Kindi in the Arab world

with the discovery of frequency analysis. [5]

A Caesar cipher with a shift of one is used on the back of the

mezuzah to encrypt the names of God. This may be a

holdover from an earlier time when Jewish people were not

allowed to have mezuzot. The letters of the cryptogram

themselves comprise a religiously significant "divine name"

which Orthodox belief holds keeps the forces of evil in check

[6].

In the 19th century, the personal advertisements section in

newspapers would sometimes be used to exchange messages

encrypted using simple cipher schemes. Kahn (1967)

describes instances of lovers engaging in secret

communications enciphered using the Caesar cipher in The

Times. [7] Even as late as 1915, the Caesar cipher was in use:

the Russian army employed it as a replacement for more

complicated ciphers which had proved to be too difficult for

their troops to master; German and Austrian cryptanalysts

had little difficulty in decrypting their messages.[8]

Caesar ciphers can be found today in children's toys such as

secret decoder rings. A Caesar shift of thirteen is also

performed in the ROT13 algorithm, a simple method of

obfuscating text widely found on Usenet and used to obscure

text (such as joke punchlines and story spoilers), but not

seriously used as a method of encryption. [9]

A construction of 2 rotating disks with a Caesar cipher can be

used to encrypt or decrypt the code.

The Vigenère cipher uses a Caesar cipher with a different

shift at each position in the text; the value of the shift is

defined using a repeating keyword. If the keyword is as long

as the message, chosen random, never becomes known to

anyone else, and is never reused, this is the one-time pad

cipher, proven unbreakable. The conditions are so difficult

they are, in practical effect, never achieved. Keywords

shorter than the message (e.g., "Complete Victory" used by

the Confederacy during the American Civil War), introduce

a cyclic pattern that might be detected with a statistically

advanced version of frequency analysis. [10]

In April 2006, fugitive Mafia boss Bernardo Provenzano was

captured in Sicily partly because some of his messages,

written in a variation of the Caesar cipher, were broken.

Provenzano's cipher used numbers, so that "A" would be

written as "4", "B" as "5", and so on. [11]

In 2011, Rajib Karim was convicted in the United Kingdom

of "terrorism offences" after using the Caesar cipher to

communicate with Bangladeshi Islamic activists discussing

plots to blow up British Airways planes or



3


disrupt their IT networks. Although the parties had access to

far better encryption techniques (Karim himself used PGP for

data storage on computer disks), they chose to use their own

scheme(implemented in Microsoft Excel), rejecting a more

sophisticated code program called Mujhaddin Secrets

"because 'kaffirs', or non-believers, know about it, so it must

be less secure". [12]

The animated series Gravity Falls uses the Caesar cipher as

one of three different ciphers (the other two being Atbash and

an A1Z26 cipher) during the end credits of the first six

episodes.

C. Mathematical Description of Caeser Cipher

To give a mathematical description of caeser cipher, First we

translate all of our characters to numbers, 'a'=0, 'b'=1, 'c'=2,

... , 'z'=25. We can now represent the caesar cipher

encryption function, e(x), where x is the character we are

encrypting, as:

Where k is the key (the shift) applied to each letter. After

applying this function the result is a number which must then

be translated back into a letter. The decryption function is:

III. DESIGN METHODOLOGY, IMPLEMENTATION AND TESTING

A. Design Methodology

This new system will use the same key for both sender and

receiver for encryption and decryption of data. The design

and flow of program will be based on the principle of

encrypting system architecture in figure I. The program

source code is displayed as shown appendix. This program

will help to achieve the goal of privacy in data

communication and telecommunication system.

Figure 1: Encrypting System Architecture

B. Testing and Implementation

The software application program was tested, and it was

observed that it performs the major objectives of the research.

The output is as in the figure below.

Data Security on Computer Network and Telecommunication System Using Caesar Cipher Cryptography Algorithm:

A Java Implementation

4


Figure 2: Interface Shown Plaintext

Figure 3: Interface Shown Cypher text



5


III. CONCLUSION

In this era of global communication through the use of

computer network, telecommunication system and devices,

the need for security of information/data from sender cannot

be over emphasized. Hence there is need for a platform to

prevent unauthorized access to information been sent from

sender to receiver on data communication and

telecommunication system. One of the best methods to

prevent such ugly occurrence of intruder or hijacker to make

use of one data is through the use of Cryptosystem. We have

developed stand-alone application software that implements

cryptography using Caesar algorithms. This program can be

implemented with chatting software or E-mail software

where the data transmitted over a data communication

network.

IV. FURTHER RESEARCH

The system does have a high confidentiality rating in order

to defend against sniffing and man-in-the-middle attacks. It

was observed that the algorithm used was focus on

encrypting only alphabetic data. This means that it cannot

guarantee full security for interception of data within

financial world and mathematics environ. Consequence to

this we proposed a further research in which the Caesar

algorithm will be modified to accommodate all alphanumeric

data and formulae symbol implemented on a computer

network.

REFERENCES

[1] D.E. Comer (2004) Computer Networks and Internets. 4th Edition.

Chapter 40: Network Security Prentice Hall, 2004.

[2] Oludipe O., Yekini N.A., and Adelokun P.A (2011). Data

Communication and Computer Network. Hasfem Publication Nigeria.

[3] Alberto Leon-Garcial and Indra Widjaja. Communication Networks,

Fundmental Concepts and Key Architecture. Second Edition,

McGraw-Hill Publishing Company, New dehlhi 2004

[4] Singh, Simon (2000). The Code Book. Anchor. pp. 14–20. ISBN

0-385-49532-3.

[5] Kahn, David (1967). The Codebreakers. pp. 775–6. ISBN

978-0-684-83130-5).

[6] Leighton, Albert C. (April 1969). "Secret Communication among the

Greeks and Romans". Technology and Culture 10 (2): 139–154.

doi:10.2307/3101474. JSTOR 3101474.

[7] Leyden, John (2006-04-19). "Mafia boss undone by clumsy crypto". The

Register.

http://www.theregister.co.uk/2006/04/19/mafia_don_clueless_crypto/.

Retrieved 2008-06-13.

[8] Luciano, Dennis; Gordon Prichett (January 1987). "Cryptology: From

Caesar Ciphers to Public-Key Cryptosystems". The College Mathematics

Journal 18 (1): 2–17. doi:10.2307/2686311

[9] Pieprzyk, Josef; Thomas Hardjono; Jennifer Seberry (2003).

Fundamentals of Computer Security. Springer. p. 6. ISBN

3-540-43101-2.

[10] Beutelspacher, Albrecht (1994). Cryptology. Mathematical Association

of America. pp. 9–11. ISBN 0-88385-504-6.

[11] Beutelspacher, Albrecht (1994). Cryptology. Mathematical Association

of America. pp. 8–9. ISBN 0-88385-504-6.

[12] Sinkov, Abraham; Paul L. Irwin (1966). Elementary Cryptanalysis: A

Mathematical Approach. Mathematical Association of America. pp.

13–15. ISBN 0-88385-622-0.

[13] Savarese, Chris; Brian Hart (2002-07-15). "The Caesar Cipher".

Retrieved 2008-07-16.

AKINYELE Akinleye Okedola

Obtained B.Sc. Electronics & Computer

Engineering from Lagos State University

and M.Sc. in System Engineering from

University of Lagos. He is a Certified

Wireless Network Administrator

(CWNA), I.T Consultant, Engineer and

a Professional Teacher. He was a head of

Department of Computer Engineering,

Lagos State Polytechnic, and presently

the Head, Record and Statistics in the

Academic Planning Unit of Lagos State

Polytechnic.

Engr. Yekini Nureni Asafe obtained his

academic qualification as follows: M.Sc.

in Computer Science, University of Lagos

Nigeria (UNILAG); B.Sc. in Electronic

and Computer Engineering, Lagos State

University (LASU), and NCE (National

Certificate in Education) in Physics Lagos

State College of Education Ijanikin

(LACOED). He is a Member Nigeria

Computer Society (NCS), International

Association of Engineers (IAENG),

International Association of Computer

Science and Information Technology

(IACSIT), and Member Institute of

Electrical Electronic (MIEEE). He has

co-author, and singular author of several

academic/research publications that has

features in some revered international

journals and conference proceedings both

in Nigeria and in abroad. He has written

about seventeen textbooks in computer

science and engineering