DESIGN AND IMPLEMENTATION OF A COMPUTERIZED DATA SECURITY SYSTEM
A CASE STUDY OF LEECON FINANCE AND INVESTMENT LTD
ABSTRACT
Having discovered the importance of computers in al ranks and aspects of life, computer system is applicable to almost all human activities and has been employed to automats most activities especially in areas were management data is of outmost importance.
Due to unauthorized access to data in database, repose disclosure or modification will invade individual process, computers have been produced with an encipher and decipher package in various computer language like C++, paschal, Fortran, visual basic etc. voting modified from or RSA cipher encryption, the package is two keys are required. The two keys are public key and secret key respectively.
The project is aimed at developing a computer data security system using data, encryption know as cryptography to LEECOM FINANCE AND INVESTMENT LTD. it also takes a look at the present data security of LEECOM FINANCE AND INVESTMENT LTD, identifying the problems encountered in carrying out these process.    
  ORGANIZATION OF WORK
This project contains seven chapter and they are as follows: -
Chapter One: - It contain the introductions of the project, stating the problem the reason why the project is being written, the aim and objectives need of observation of the project, the limitation of the project, the assumption and the definition of terms of the project.
Chapter Two: - Is all about the literature review of the project.
Chapter Three: - Highlight the description and analysis of the existing system, the objectives of the existing system, problem encountered in the system were also highlighted, the limitations are also stated.
Chapter Four: - Entails the development of the design of the new system, the input/output specification and design, the file design, the system requirement.
Chapter Five: - Consists of implantation of the program design, the program flowchart, pseudo code, the source program and the test of run and also explained.
 Chapter Six: - Talks about the system, documentation program documentation and use documentation.  
Chapter Seven: -  Finally, talks about the conclusion and recommendation of the project.  
TABLE OF CONTENTS
 CHAPTER ONE
1.1     INTRODUCTION
1.2     Background of the Study
1.3     Statement of the Problem
1.4     Purpose of Study
1.5     Importance of Significance of the Study
1.6     Scope and Delimitation
1.7     Limitation
1.8     Assumption
1.9     Definition of Term
 CHAPTER TWO
2.1     LITERATURE REVIEW  
 CHAPTER THREE
3.1     Description and Analysis of the Existing System
3.2     Facts Findings Methods Used
3.3     Objectives of the Existing System
3.4     Organizational Structure
3.5     Input, Process and Output Analysis
3.6     Information Flow Diagram
3.7     Problem of the Existing System
3.8     Justification for the New System
 CHAPTER FOUR
4.1     Design of the New System
4.2     Input Specification and Design
4.3     Output Specification and Design
4.4     File Design
4.5     Production Chart
4.6     System Flow Chart
4.7     System requirements
 CHAPTER FIVE
IMPLEMENTATIONS
5.1     Program Design
5.2     Program Flow Chart
5.3     Pseudo Code
5.4     Source Program
5.5     Test Run
 CHAPTER SIX
DOCUMENTATION
 CHAPTER SEVEN
RECOMMENDATION AND CONCLUSION
7.1        Recommendation
7.2        Conclusion
REFERENCE
CHAPTER ONE 
1.0       INTRODUCTION
1.1    BACKGROUND OF THE STUDY
When writing is new in a society, there will not be any data security, since the script itself is a cryptogram intelligible only to the few whom can read or write. But as literacy spread, cryptology appears soon after. This is true for the society in which we fine ourselves today.
According to Demmy (1989) data security simply means the act of protecting something against attack, security is done as a result of safety.
This is done to avoid the misuse of information relating to people of corporate bodies, whereby we protect our computer and data against unauthorized disclosure, modification and also security the system against virus and damage that might be caused by external force.
During the ancient times, record keeping was done by means of primitive notches cut into wooden stick, on bone fragments or marks pressed in clay tables. They soon improved with the development of papyrus and calamus pen. The ancient record keeping was well in hand and reached its peak in Roman Republic and Roman Empire.
The census of 1890 turned out to be especially significant in the evolution of recorded machine processible form, for this census. Harman Hollevith has developed the punched card as a unit record and invented machinery for processing these records some 60years later, the first electronic computer was constructed and their application in record keeping system ushered in the era of computerization.
From this humble beginning of antiquity, record keeping has grow into gigantic dimensions wit the advent of computer network, conferencing through computers and so on.
These have increased the vulnerability of data both in stored form during communication to wire tapping; saving and accessibility. Another reason is that complexity of interaction of individual with their governments. With these new dimension dangers surfaced private and confidential records could easily become public property. This endangering with lives of people concern.
A solution had to be found to his problem of insecurity of data. A common technique for providing data security to sensitive information is encryption. Encryption entails the application of certain reversible transformation; to the message to be transmitted to render them unintelligent to all but those receivers who are in possession of the correct “key” used to encryption.
The original message is decrypted by applying the reverse transformation specified by the key to the received encrypted message.
Suppose two people A and B wish to communicate or exchange message on an issue they do not want to make public on what they want to keep between them. A number of questions or problems arise. These are: -
i.             How can they make sure that no other person receives this message?
ii.           How can A (B) make sure that B (A) receive all of A’s call of B’s message?
iii.          How can they make sure that they receive only these message and no other?
It can be seen that these present some real problem. As an illustration let us consider a business deal between two businessmen, A and B, geographically residing in two different areas and who communication with each other in some way, example by E-mail, mail, telephone, telex etc. another businessman Y, business vital Y, wishing to know what the deal is all about, may be able to tap into the communication line thus leading to problem.
As state above
i.             May rise in a situation whereby the vital Y, may decided to intercept the message from A to B, say, causing a delay in the cause of the business deal. This message might be easily detected if the recipient of the message does not get it at the said time, unlike problem.
ii.           Whereby the message interception may be distorted or some message not there before may be added to it before being sent to the recipient. In a situation like this it is quite difficult to detect.
However, detection of an abnormal situation does not imply that it can be determined who caused it. Thus to ensure orderly communication of confidential message it is necessary that the authenticity of message be proved conclusively at some later point in time to any other party. Having established the fact that there is a multitude of problems with the notion of communication on despite its deception simplicity, and by extensions having decided that it is desirable to resolve this problem, we now direct our attention to possible solution.
 
1.4    PURPOSE OF STUDY
This project work is carried out to make sure for maximum computerized data security system. It also prove the usefulness of computer in the case study. It will also enlighten the student in the course of studying relating to other fields of life.
This project will also provided detailed information on the concept of data security. The importance of computerize and the importance of data security in the field. There is always the need in lives of individuals and corporation for privacy and secrecy. The purpose of study of this project of computer data and information.
 1.5    IMPORTANCE OF STUDY
The study work ensures that data (information) will be secured against unwanted bodies; by developing a better data security system for the company (LEECON FINANCE AND INVESTMENT LIMITED).
This study will also enable us to investigate a secured cryptosystem.
 1.6    SCOPE
Security is required in any environment where information or items are not intended to be freely available to all. Depending on the medium through which this information is being passed across, different security measures are taken.
The physical security of the hardwares can be protected by conventional methods such as a secure room and cardkeys, but the study of this is beyond the scope of this work.
However, within this work, will be looking at one of the measure taken in security information when it is being transmitting from the transmitter to the receiver. In this case the problem is to write the message in such a way that an enemy or eavesdropper on the communication medium (which could be a paper, information-theoretic channel or a physical file on the computer system) cannot deduce or understand the content is of the message.