The Evolution Of Cryptography Computer Science Essay

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In fast growth of information technology development require a reliable system in protecting the data sent between two legitimate parties. As well as the people become more intelligent in hacking system and stealing the data which one of the reason why we need a secure system to protect the data from eavesdropper. Quantum cryptography is developed to solve this problem to replace the classical cryptography in part of key distribution.

Due to continuous growth of the Internet, wireless communication is become very popular. Wireless has tangible benefits that mobilize the user in doing their task anywhere at any time. Wireless enables better communication, enhances productivity and enables better customer service. Wirelesses LAN allow users to access information beyond their desk anywhere within their office places. Furthermore, wireless LAN's are faster and easier to deploy than cable networks. By using wireless, it eliminates the needs for complex cabling and construction while it well suited in many environments. Wireless LAN become as an extension to wired network because it allows access anywhere within the building. It solves the problem occur of network cabling such as for the heritage building or sites where new wiring cannot be laid for structural reason, wireless is ideal.

Thus, the security of the data is very important as wireless become one of the main communication medium to the users. Cryptography was invented in order to secure to data from intruders. Classical cryptography for example DES has been approved is not secure while it can be easily to break. As a solution for insecure algorithm, Quantum Cryptography was invented based on quantum mechanics

Background and Motivation

The evolution of cryptography had become an endeavor of the invention of quantum cryptography in order to provide a secure key distribution for as a secret key used to encrypt and decrypt the message between two legitimate parties. Due to continuous growth of the Internet, wireless communication is becoming very popular. Wireless LAN has been implemented by Wireless Internet Service Provider based on IEEE 802.11 standard. WLAN has been widely used in public area which also called as Wi-Fi hot-spot where the number of users has increased rapidly. The used of WLAN not only limited for laptop and Personal Digital Assistant (PDA) where many new mobile devices such as cellular phones, portable media player, and portable game devices tend to support connectivity in wireless zones.

In IEEE 802.11 group provide many types of protocol standard, for this paper IEEE 802.11i standard has been chosen as the communication platform because of the specification provided. IEEE 802.11i is an amendment of the original IEEE 802.11 standard specifying security in wireless network.

The requirement of security in wireless communication is necessary as well as in wired link. The flaws in key distribution in conventional cryptography had encouraged the invention of quantum cryptography as the solution.

Infrastructure of 802.11i Wireless LAN

Wireless LANs (WLANs) used electromagnetic radio waves to transport data between computers in a Local Area Network (LAN), without the limitations set by network cable or phone wire connection.  Whilst simple optical links are commercially available, radio is presently more useful since it is not strictly restricted to line-of-sight paths.

Radio waves were also known as radio carriers when they are used to carry information. The data carried by the radio is modulated on the radio carrier by various modulation techniques. It allows the data to be faithfully reconstructed at the receiving end. After the data is modulated onto radio carrier, this combined radio signal and occupies more than single frequency since the frequency components of the modulation data add frequency bandwidth to the basic carrier which is in direct proportion to its information content or bit rate. The frequency range which is needed to accommodate a radio signals with any given modulation bandwidth is called a channel. Radio receiver techniques can select one radio channel while efficiently rejecting signals on other frequencies. Many radio signals to and from many users can thereby co-exist in the same place and time without interfering with each other if the radio waves are transmitted at minimum necessary power within different radio channels.

Quantum Key Distribution (QKD)

Quantum cryptography has become a new approach in network security which based on quantum mechanics focusing on Quantum Key Distribution (QKD). Unlike classical cryptography which relies on mathematical complexity, quantum cryptography uses polarized light photons to transfer data between two points which relies on laws of quantum physics. This law provides the secure communication channel where ensures that nobody can measure a state of an arbitrary polarized photo. The disturbance by eaves can be detected by legitimate user which can inform the user to end the communication. Thus, as all eavesdropping can be detected, quantum cryptography can considered as a promising key distribution towards long term unconditionally secure cryptosystem [1]. The first QKD protocol called as BB84 was developed by two computer scientists in the early of 1980s, Charles Bennett a researcher for IBM, and Gilles Brassard from the University of Montreal. They realized that the application of quantum theory in cryptography could have the potential to create a cipher giving absolute security for eternity.

In addition, quantum cryptography in wireless networks is still premature and most research experiments aim at providing QKD services outdoor for a long distance in satellite networks or between buildings in the city [2]. This thesis focuses on security in UDP 802.11i WLAN by implementing the BB84 protocol as the key distribution system to provide a high secure data transmission between two legitimate parties. This protocol is implemented in UDP connection instead of TCP to obtain the strong result with eavesdropper existence and high presence of noise in communication medium. Therefore, we can compare the result of key length and error rate between UDP and TCP connection. The result will conclude the reliability of the Quantum Cryptography as a secure system for key distribution in cryptography.

User Datagram Protocol

User Datagram Protocol (UDP) is a connectionless and unreliable network protocol and only concern about speed where streaming media such as video and audio streaming is more compatible to use UDP protocol. The speed is much better than TCP regarding to no form of flow control where there is no acknowledgement, error checking and error correction is done during the communication. Thus, when the data sent over the network, it is affected by the collision and will present the error.

UDP contains higher error rate rather than TCP because of the packet send through the datagram and it is connectionless and will not resend the packet loss. It will keep send the data until finish and the packet loss in between the transmission will be ignored and will not resend back.

Problem statement

This research has done due to the level of security in wireless communication. QKD has been done in wired medium and the result shows that it can detect the eavesdropper. Thus, this method should be implemented in wireless medium as main communication medium after wired medium to communicate to each other. Wireless medium is much easier to be hacked by eavesdropper which is in the same time the level of noise is also much higher than wired medium

Research Objectives

In this research, the objective has been determined and summarize in the following points:

To provide secure communication channel in wireless medium by replacing classical cryptography with quantum key distribution protocol. Implementation of Quantum Key Distribution can be a solution to provide a secure channel in wireless medium.

To identify the effectiveness of BB84 protocol in UDP WLAN as a target solution to overcome the problem in key distribution system in classical cryptography in order to provide a secure medium for users.

The hypothesis of this research is by implementation of the proposed method on UDP WLAN, we will obtain the different key length and error rate estimation depending on set value on bit sent at Alice’s side.

This research objective will be as a main guide to obtain the final result as expected.

Research Scope

The scope of this research will study on the security on UDP WLAN as the key element in propose a method to secure the wireless environment. The Formal methodology has been defined and used comprehensively in this research to meet the research objectives.

The simulator is build using JAVA Language to perform the test bed implementation on UDP WLAN. The value of bit sent from Alice to Bob can be change starting from the minimum value which is 9999bits until the maximum value which is 100000bits. The research mainly focuses on the final key length that will be retrieved at the end of the simulation. The percentage of error rate can be analyzed from the final key.


From this research, the contribution in wireless network security is become the main purposes in this project where it can provide guarantee security protection in securing the data during the transmission. The detection of eavesdropper presence is the most important in order to overcome the previous problem in classical cryptography.

Thesis Organization

This work presents the phenomena of security in wireless environment which measuring error rate of communication and also final key length obtained in order to provide the security guarantee in the certain communication.

The structure of this thesis is organized as follows: Chapter 2 will discuss and briefly summarized about the general view of IEEE 802.11i WLAN, UDP over wireless, brief history of Quantum Key Distribution and also security protocol used in this implementation.

Chapter 3 introduces the methodology of the implementation on security guarantee in UDP wireless communication. BB84 protocol is used to secure the data during the communication and also to provide the security guarantee. The architecture and the implementation of simulator discuss in this chapter.

While in chapter 4 will discuss the result obtained from the process done in methodology and discuss the result and affect from the communication medium used. In chapter 5 will conclude with a summary and conclusion of the research reported in the previous chapter. Besides, the future studies of this research will be highlighted at the end of this chapter.

[1]Fluhrer, S., I.Martin, and A.Shamir. “Weaknesses in the Key Scheduling Algorithm of RC4.” Eight Annual Workshop on Selected Areas in Cryptography, August 2001.