Design and Implementation of Computer Security: Data Encryption, Decryption and Key Hash Algorithms
Chapter One
OBJECTIVES OF THE STUDY
- To understand and improve the computer data security through encryption of data.
- To provide a means of safeguarding data in a system
- To enhance the integrity of data
- To facilitate the use of more sophisticated tool against hacking, cracking, bugging of a system.
- To develop a platform to complement physical security.
CHAPTER TWO
LITERATURE REVIEW
THE CONCEPT OF CRYPTOSECURITY
Security is the quality or state of being secure: – a relief from exposure to danger, and making safe against adverse contingencies. But encryption alone is not sufficient. Proper key selection, key management, physical security, people security and procedures to ensure that the plain-text does not leak out of the system via loopholes are all essential for a secure computer data system. The strength of a good crypto-system does not depend on keeping its algorithm secret; the security of the cipher text relies solely on the secrecy of the key.
Stewart, Ed Tiltel and Mike(2000) defined Cryptography as added security to data during processing, storage and communications. They further described the various types of cryptography such as Symmetric Key Cryptography and Asymmetric Key Cryptography or Public Key. Kessler (1998), described cryptography as the science of writing in secret code. He further describes it as one essential aspect for secure communication. In data communication and telecommunication, cryptography is necessary when communicating over any untrusted medium, which includes just about any network, particularly the internet.
Cryptography, then, not only protects data from theft or alteration, but can also be used for user authentication. Burnett and Panini(2004) outline the security requirement which include the following:
- Authentication
- Privacy/confidentiality
- Integrity
- Non-repudiation
Liddell and scolt(1996) stated in their book that in the famous Greek drama the ‘Iliad’, cryptography was used when Bellerophon was sent to the king with a secret tablet which told the king to have him put to death. The king tried to kill him by having him fight several mythical creatures, but he won every battle.
The Spartans used a system which consisted of a thin sheet of papyrus wrapped around a staff (now called a “staff cipher”). Messages were written down the length of the staff, and the papyrus was unwrapped. In order to read the message, the papyrus had to be wrapped around a staff of equal diameter. Called the ‘skytale’ cipher, this was used in the 5th century B.C. to send secret messages between greek warriors. Without the right staff, it would be difficult to decode the message using the techniques available at that time. The following version of the alphabet demonstrates the technique. First we see the wrapped version of the alphabet, then the unwrapped version.
ADGJMPSVY
BEHKNQTWZ
CFILORUX
ADGJMPSVYBEHKNQTWZCFILORUX
Fig, 2.1 skytale cipher
Another Greek method was developed by Polybius (now called the “Polybius Square”). The letters of the alphabet would be laid out in a five by five square (similar to the later Playfair method) with i and j occupying the same square. Rows and columns are numbered 1 to 5 so that each letter has a corresponding (row,column) pair. These pairs could easily be signaled by torches or hand signals. Decryption consists of mapping the digit pairs back into their corresponding characters. This system was the first to reduce the size of the symbol set, and in a loose sense it might be considered the forerunner of modern binary representations of characters. Try decoding the message on the right.
CHAPTER THREE
RESEARCH METHODOLOGY AND SYSTEM ANALYSIS
SYSTEM INVESTIGATIONS AND ANALYSIS
System investigation is concerned with the in-depth and comprehensive study carried out upon the old system so as to find out relevant facts that will be of help in designing the new system.
The task of investigation comprises the following:-
- Fact finding
- Analysis of data collected
FACT FINDING
This involves gathering facts about the existing system. The purpose of fact finding is to identify the application and the implication of system to the management.
RESEARCH METHODOLOGY
This research is based on the investigation undertaken in order to discover new facts information. The methodology studies the methods that are necessary to achieve the required subjects and facts. Meanwhile, the method adopted for this research is data collection to ensure authenticity of the final research. Whereas, methodology is a structured approach to a particular task.
Therefore, research methodology is a detailed description of what the researcher planned and procedures adopted in gathering new facts relevant to the project work.
SOURCES OF DATA
The major source of data in this research is the secondary, which represents work already done in the research and includes the following information from:
- Textbooks
- Computer journals
- Newspapers
- Magazine
- Articles
- Library
- Internet
CHAPTER FOUR
SYSTEM DEVELOPMENT AND IMPLEMENTATION
In order to implement a cryptography system using the python programming language, a python toolkit including various cryptography modules will be downloaded in order to be able to import the modules in the program. The name of this toolkit is “Pycrypto”.
Pycrypto is a collection of both secure hash functions (such as MD5 and SHA), and various encryption algorithms (AES, DES, IDEA, RSA, ElGamal, etc.). The package is structured to make adding new modules easy. I consider this section to be essentially complete, and the software interface will almost certainly not change in an incompatible way in the future; all that remains to be done is to fix any bugs that show up.
CHAPTER FIVE
SUMMARY
From the pre-explaind analysis of the program, it’s goal had been demonstrated by making use of some major programming functions like performing loops. Python allows for the use of FOR LOOPS and WHILE LOOPS. In this program, the while loop was used at various instances. It was used to allow restarting of the program after first execution. It was also used to create a loop that will handle the counting of the encryption key. To restrict users of the program, the IF conditional statement handles that area letting the encryption continue only IF the encryption key is counted as 16 characters.
REFERENCES
http://docs.python.org
http://python.org
http://khanacademy.org
http://en.wikipedia.com/wiki/Python
RECOMMENDATION
For users of the code, the python console will work just fine but if the user is not eligible enough, it will be preferred for them to make use of a Python IDE (Integrated Development Environment) like the popular IDLE built with Tkinter. Additionally, Python2.7 was used to write this code so the keywords and language functions that have changed in Python3 may cause some bugs to occur if it’s used with a Python3 interpreter.
Having presented all that is needed for the successful implementation of this project. The following recommendations are suggested by the researcher aim at improving / correcting some lapses.
* Developers and engineers need to understand crypto in order to effectively build it into their products.
* Sales and marketing people need to understand crypto in order to prove the products they are selling are secure.
* The customers buying those products, whether end users or corporate purchasing agents, need to understand crypto in order to make well-informed choices and then to use those products correctly.
* IT professionals need to understand crypto in order to deploy it properly in their systems.
* Even lawyers need to understand crypto because governments at the local, state, and national level are enacting new laws defining the responsibilities of entities holding the public’s private information.
CONCLUSION:
Today the importance of security in communication and network systems have come a long way to ensure that information transmitted between two or more parties involved in a conversation enjoys the benefits of privacy. In spite of the technological advancements to promote a secure path for communicating parties, most communication still leaves some kind of recorded trail. For example, communications over telephone lines, including faxes and e-mail messages, produce a record of the telephone number called and the time it was called. Financial transactions, medical histories, choices of rental movies, and even food choices may be tracked by credit card receipts or insurance records. Every time a person uses the telephone or a credit card, the telephone company or financial institution keeps a record of the number called or the transaction amount, location, and date. In the future, as telephone networks become digital, even the actual conversations may be recorded and stored. All of this amounts to a great potential loss of privacy. Cryptography is one tool that will be able to ensure more privacy.
BIBLIOGRAPHY
- Becket, B.(1998), Introduction to Cryptography. London, Blackwell Scientific Publication.
- Behrouz, A., Networking. 54 & Forouzan, P.(2004), Data Communication and New York. Nashville, TN: Vanderbilt University Press.
- Burnett, S., & Paine, S.(2001), RSA Security Official Guide To Cryptography. Berkeley, CA: Osborne/McGraw-Hill Press.
- Burton, S., Kaliski, J., Matthew, B., &Robshaw, J.(1994), Linear Cryptography Using Multiple Approximations. London: MIT Press.
- El Gamal, T.(1985), A Public Key Cryptosystem and a Signature Scheme Based On Discrete Logarithms. New York: Macmillan Publishing Company.
- Lars, R., Knudsen, J., and Erik, M.(2000), A Chosen Plaintext Linear Attack On DES. New Jersey: Prentice Hall Inc. Press.
