ENCRYPTION AND DECRYPTION TECHNIQUES FOR SECURING COMMUNICATION IN A NETWORK USING SYMMETRIC ALGORITHM

ABSTRACT

Often there has been a need to protect information from ‘prying eyes’. In the electronic age, information that could otherwise benefit or educate a group or individual can also be used against such groups or individuals. Industrial espionage among highly competitive businesses often requires that extensive security measures be put into place. And, those who wish to exercise their personal freedom, outside of the oppressive nature of governments, may also wish to encrypt certain information to avoid suffering the penalties of going against the wishes of those who attempt to control. The project work attempts to solve the problem of data security in organizations, schools etc. using a cryptographic method called encryption/decryption. Encryption is the process of transforming information (referred to as plaintext) using an algorithm (called cipher) to make it unreadable to anyone except those possessing special knowledge, usually referred to as a key. Decryption is the process of converting encrypted data back into its original form, so it can be understood.

TABLE OF CONTENT
Title Page – – – – – – – i
Approval Page – – – – – – ii
Declaration – – – – – – – iii
Dedication – – – – – – – iv
Acknowledgement – – – – – – v
Abstract – – – – – – – vi
Table of Content – – – – – – vii-x
CHAPTER ONE
1.1 Introduction – – – – – 1-3
1.2 Objectives of the study – – – – 3
1.3 Significance of the Study – – – 3-6
1.4 Scope of Study – – – – – – 6
1.5 Limitation of study – – – – 7
CHAPTER TWO
2.1 Literature Review – – – – – 8
2.2 Early vs Modern Cryptography – – – – 9-10
2.3 Forms of Cryptosystems – – – – – 11-13
2.4 Overall Trends in the Research – – – – 13-17
2.5 The Proposed System – – – – – 18-21
2.6 System Methodology – – – – 22
2.6.1 Extreme Programming (XP) Methodology – – 22
2.6.2 XP Core Practices – – – – – 22-25
2.6.3 Reasons for Choosing Extreme Programming (XP) – 25-26
2.7 Justification of Study – – – – – 26-27
CHAPTER THREE
3.1 System Analysis – – – – – 28
3.2 Existing System – – – – – – 28-29
3.3 Proposed System – – – – – 29
3.4 System Design – – – – – – 30
3.5 Logical Situation – – – – – 30-32
3.6 Algorithm of the Application – – – – 32-34
3.7 Overall Flowchart – – – – – 35
3.8 Class Diagram – – – – – 36-38
3.9 Security Consideration – – – – – 38-39
3.10 Input Design – – – – – – 39-41
3.11 Output Design – – – – – 41
3.12 Database Specification – – – – – 41
3.13 Choice of Programming Language – – – 42
CHAPTER FOUR
4.1 System Requirement – – – – – 43-44
4.2 System Installation – – – – – 44
4.3 System Documentation – – – – – 44-45
4.4 User Training – – – – – – 45
4.5 System Development – – – – – 45-47
4.6 Implementation – – – – – 47
4.7 Program Testing – – – – – 47-48
4.7.1 Desk Checking – – – – – – 48
4.7.2 Alpha Testing – – – – – – 48
4.7.3 Beta Testing – – – – – – 48-49
4.8 System Conversion – – – – – 49
4.8.1 Pilot Conversion – – – – – – 49
4.8.2 Phased Conversion – – – – – 49
4.8.3 Parallel Conversion – – – – – 50
4.9 Recovering Security – – – – – 50
4.10 Usability Documentation & Procedure – – – 50
4.11 Quality Assurance – – – – – 51
CHAPTER FIVE
5.1 Summary – – – – – – 52
5.2 Conclusion – – – – – – 52-53
Reference – – – – – – 54-55
APPENDIX – – – – – – 56-65

CHAPTER ONE

1.1 INTRODUCTION

In today’s world where much of our personal information and financial transactions are processed via the Internet, data encryption is an essential element to any effective computer security system. This activity is why encryption is important. One of the main reasons why encryption is important has to deal with the way information is sent via the Internet. Keeping your personal data secure when using a personal computer may not be as simple as you think. Any time that you send information across the Internet, it can be viewed by just about anyone that would want to see it. The data is first sent to your local network (the same network that is used by other people who live in your area).  The information then travels to your Internet service provider, who can view this information. Your data then travels along a variety of routes to reach the Internet service provider for the party that is supposed to receive your information. Finally, the person who your information was intended for finally receives it. During this process, numerous people could possible obtain access to the information that you are sending. So you can see why encryption is important and it is vital to have an encryption system in place. You may feel that your computer is sufficiently protected with the router that you are operating behind. Think again. Another reason why encryption is important is the fact that any other computer in your home or even your laptop can be infected with a virus that can be passed directly back to your PC the minute these other devices are plugged in to your home network.

The use of Internet services that are available in hotels and coffee shops are not as secure as you may think they are, leading to another good reason as to why encryption is important. These types of Internet systems are set up to protect all the customers that are using this form of communication from outsiders, but they do not protect the customers from each other. Anyone that is using the same service in one of these locations can view your information while you are working on it. Why encryption is important has to do with the way that these security systems work. The encryption programs will disguise your data, making access to it impossible without the use of a personal password. There are two different types of these security systems-the hardware version and the software version. Each of these encryption systems has its advantages as well as its disadvantages. If you pass a large amount of your communications and personal information across the Internet , you should protect yourself from unauthorized persons from having access to this data. That is why data encryption is important.

1.2 Objectives of the study
Sending sensitive messages and files over the Internet/network is dangerous as all emails are transmitted in an unsecured form. The objective of this project is to provide a secured approach to perform file transfers and messages over a network.

1.3 Significance of the Study
The most important reason for using encryption is to preserve confidentiality. This means that only an authorized receiver can read the message (the receiver must have the appropriate decryption key).
Transaction Security
Most web sites use SSL (Secure Sockets Layer) to encrypt customer credit cards during an on-line transaction so they cannot be intercepted by attackers. SSL uses a public and private key system to create a secure link between a customer and web site, protecting the transaction against attack.
Most web site transaction systems and shopping cart software offer SSL as standard, and most browsers support it.

Post-Transaction Security.

Credit cards are not just vulnerable during a transaction; they can be just as vulnerable, to employees and hackers, if they are stored without encryption on unsecured computers. Encryption is increasingly being used by small businesses to protect credit cards that are stored after a transaction, so these cards are still protected even if an intruder manages to breach security.

Securing Confidential Files
While passwords are often a good protection for sensitive files, they may not be enough to protect a company’s most sensitive information. Encryption offers an added layer of security, protecting against the risks often created by poor password management. There are numerous low-cost packages available that will provide desktop encryption to protect files on a hard drive.

E-mail Security
As soon as a user clicks SEND on an e-mail, that e-mail becomes public property. Not only can it be intercepted, it can also remain on all the servers it passed through, for months if not years.
Encryption is therefore important to prevent sensitive e-mails and their attachments from being read by the wrong people.
There are a number of low-cost e-mail encryption packages on the market, such as ZixMail, that will enable a recipient to decrypt an encrypted e-mail even if they don’t use an encryption product. These products are convenient, easy to use, and affordable, and should be used regularly in any business.