PSEUDO RANDOM NOISE BASED SPREAD

SPECTRUM MODULATION SCHEME FOR SECURE

UWB WIRELESS COMMUNICATION

BY

SITI HAZWANI YAACOB

A dissertation submitted in fulfilment of the requirement

for the degree of Masters of Science in Communication

Engineering

Kulliyyah of Engineering

International Islamic University Malaysia

DECEMBER 2014

ii

ABSTRACT

A Pseudo Random Noise Generator (PRNG) using 24 bits Linear Feedback Shift

Registers (LFSR) have been proposed to generate a sufficiently long period of key

sequence for a secure UWB communication application. The Direct Sequence Spread

Spectrum (DSSS) principle is employed in the system as a data modulation and

transmission technique due to its low Power Spectral Density (PSD).The investigation

is carried out to analyze the performance of UWB pulse generator by using Avalanche

transistor which able to generate nanosecond pulses that contained data embedded

with the key to be transmitted. The designed UWB transmitter circuit has been

simulated using NI Multisim 11.0. The circuit successfully generated a kind of

inverted Gaussian pulses with the best pulse width achieved is 1.91 ns and pulse

amplitude is 5.72V. The Power Spectral Density (PSD) of the pulses satisfies the

specification of FCC mask defined with the magnitude of -81.5 dBm at 3.1GHz

frequency. In fact, the PRNG pass the NIST Test Suite randomness tests. With the

features such as simple structure, high speed and low power as low cost this circuit

system is applicable to UWB wireless communication system.

iii

لبحثا صملخ

تغذية راجعة خطية و سعة قترح استخدام مولد ضجيج شبه عشوائي يستخدم مسجل ذو ا

خانة، لانتاج متسلسلة مفتاح طويلة بما فيه الكفاية لتأمين تطبيقات الاتصال على 42ظف في النظام و النطاقات فائقة السعة.مبدأ تمديد الطيف بالاستخدام المباشر للمتسلسلات

حقيق تم كمعدل للبيانات و كتقنية للارسال نسبة لانخفاض كثافة طيف القدرة لديه. التلتحليل اداء مولد نبضات لنطاقات فائقة الاتساع، و ذلك باستخدام ترانزستور افلانش الذي له قدرة على توليد نبضات بطول في حدود جزء من الالف مليون جزء من الثانية و التي احتوت على بيانات مضمنة مع المفتاح ليتم ارسالها.دائرة النطاقات فائقة السعة المصممة

(. الدائرة انتجت بنجاح شكل من NI Multisim 11.0اكاهاا باستخدام برنامج تمت محجزء من الالف مليون 19.1نبضات جاوسالمعكوسة، و كان افضل طول للنبضة تحقق هو

فولت.كثافة طيف القدرة للنبضات وافق المواصفات 29.4جزء من الثانية و مقدار النبضة صالات الاتحادية بالولايات المتحدة الامريكية، و الذي الموصى عليها بواسطة مفوضية الات

قيقا هيرتز. اجتاز مولد الضجيج شبه 191مل ديسبل عند تردد 5192-يبلغ مقداره العشوائيمجموعة اختبارات العشوائية المصممة بواسطة المعهد الوطني للمعايير و التقنية

البنية البسيطة و السرعة العالية و القدرة بالولايات المتحدة الامريكية.بخصائصه المتمثلة في المستهلكة المنخفضة بالاضافة لتكلفة الانتاج المنخفضة، هذه الدائرة تعتبر مناسبة للتطبيق

على انظمة الاتصالات اللاسلكية التي تعمل على النطاقات فائقة السعة.

iv

APPROVAL PAGE

I certify that I have supervised and read this study and that in my opinion; it conforms

to acceptable standards of scholarly presentation and is fully adequate, in scope and

quality, as a dissertation for the degree of Master of Science in Communication

Engineering.

…………………………………..

Sheroz Khan

Supervisor

I certify that I have supervised and read this study and that in my opinion; it conforms

to acceptable standards of scholarly presentation and is fully adequate, in scope and

quality, as a dissertation for the degree of Master of Science in Communication

Engineering.

…….……………………………..

Mohammad Umar Siddiqi

Co Supervisor

I certify that I have read this study and that in my opinion it conforms to acceptable

standards of scholarly presentation and is fully adequate, in scope and quality, as a

dissertation for the degree of Master of Science in Communication Engineering.

…………………………………..

Mohamed HadiHabaebi

Internal Examiner

This dissertation was submitted to the Department of Electrical and Computer

Engineering and is accepted as a fulfilment of the requirement for the degree of

Master of Science in Communication Engineering.

…………………………………..

Othman O- Khalifa

Head, Department of Electrical

and Computer Engineering

This dissertation was submitted to the Kulliyyah Engineering and is accepted as a

fulfilment of the requirement for the degree of Master of Science in Communication

Engineering.

…………………………………..

Md. Noor Hj. Salleh

Dean, Kulliyyah of Engineering

v

DECLARATION

I hereby declare that this dissertation is the result of my own investigation, except

where otherwise stated. I also declare that it has not been previously or concurrently

submitted as a whole for any other degrees at IIUM or other institutions.

SitiHazwaniBintiYaacob

Signature…………………. Date …..................

vi

INTERNATIONAL ISLAMIC UNIVERSITY MALAYSIA

DECLARATION OF COPYRIGHT AND AFFIRMATION

OF FAIR USE OF UNPUBLISHED RESEARCH

Copyright ©2014 by International Islamic University Malaysia. All rights reserved.

PSEUDO RANDOM NOISE BASED SPREAD SPECTRUM MODULATION

SCHEME FOR SECURE UWB WIRELESS COMMUNICATION

No part of this unpublished research may be reproduced, stored in a retrieval system,

or transmitted, in any form or by any means, electronic, mechanical, photocopying,

recording or otherwise without prior written permission of the copyright holder except

as provided below.

1. Any material contained in or derived from this unpublished research may

be used by others in their writing with due acknowledgement.

2. IIUM or its library will have the right to make and transmit copies (print

or electronic) for institutional and academic purposes.

3. The IIUM library will have the right to make, store in a retrieval system

and supply copies of this unpublished research if requested by other

universities and research libraries.

Affirmed by SitiHazwaniBintiYaacob

……..……..…………… …………………..

Signature Date

vii

ACKNOWLEDGEMENTS

It has been a long awaited journey to complete this thesis. Alhamdulillah. Praise to

Allah s.w.t. Without His blessing, all my hard work would not come to an impressive

result. One other important factor in completing this thesis is the guidance of my

supervisor Assoc. Prof. Dr. Sheroz Khan and my co-supervisor Prof. Dr. Mohammad

Umar Siddiqi. Their guidance is the key to my success. Thank you very much, I really

appreciate their support. Last but not least, my most heartfelt gratitude is reserved to

my husband and mother for their patience, trust, and belief in my endeavor.

viii

TABLE OF CONTENTS

Abstract .......................................................................................................................... ii Abstract(Arabic)............................................................................................................ iii Approval page ............................................................................................................... iv Declaration ..................................................................................................................... v

Copyright Page .............................................................................................................. vi Acknowledgement ....................................................................................................... vii List of Tables ................................................................................................................. x List of Figures ............................................................................................................... xi

List of Abbreviations .................................................................................................. xiii List of Symbols ........................................................................................................... xiv

CHAPTER 1: INTRODUCTION ............................................................................... 1 1.1 Background ................................................................................................... 1

1.2 Problem Statement ........................................................................................ 4

1.3 Research Scope ............................................................................................. 5

1.4 Research Methodology ................................................................................. 6

1.5 Research Objectives...................................................................................... 7

1.6 Thesis Outlines ............................................................................................. 7

CHAPTER 2: LITERATURE REVIEW ................................................................... 9 2.1 Background of Secure UWB Communication ............................................. 9

2.2 Contemporary Techniques .......................................................................... 13

2.3 Summary ..................................................................................................... 16

CHAPTER 3: METHODOLOGY ............................................................................ 17 3.1 Introduction................................................................................................. 17

3.2 Experimental Tools ..................................................................................... 17

3.2.1 Simulation Tools ................................................................................................. 18

3.2.2 NIST Test Suites Tools ....................................................................................... 19

3.3 Specification of Proposed Circuit ............................................................... 19

3.4 Circuit Level Mechanism ........................................................................... 22

3.5 Methodology Procedures ............................................................................ 27

3.6 Randomness Tests ...................................................................................... 29

3.7 Summary ..................................................................................................... 38

CHAPTER 4: RESULTS, ANALYSIS AND DISCUSSION ................................ 39

4.1 Introduction................................................................................................. 39

4.2 Simulation Results ...................................................................................... 39

4.2.1 Effect of Changing Component Values .............................................................. 44

4.2.2 PSD Validation ................................................................................................... 47

4.3 Randomness Test Evaluation ...................................................................... 54

ix

4.4 Summary ..................................................................................................... 56

CHAPTER 5: CONCLUSION .................................................................................. 57

5.1 Conclusion .................................................................................................. 57

5.2 Recommendation ........................................................................................ 58

REFERENCES ........................................................................................................... 60

x

LIST OF TABLES

Table No.

Page No.

2.1 Comparison of techniques used in a few related works 15

3.1 The simulation components list 18

3.2 The circuit components specification 20

3.3 The subblock and maximum run 32

3.4 The subblock and the longest run 32

3.5 The L-bit blocks and the content 34

3.6 The possible L-bit value and the location 35

3.7 The computed Li, Ti values and its determination 37

4.1 The output pulse parameters changes with Avalanche

capacitor C3

46

4.2 Performance comparision of UWB pulse generator using

Avalanche Transistor with previous designs

46

4.3 Power Spectral Density (PSD) magnitude of UWB pulses

changes with Avalanche capacitor at frequency ≥ 3.1GHz

53

4.4 NIST randomness test results 54

4.5 The comparison of NIST randomness tests with previous

PRNG

55

xi

LIST OF FIGURES

Figure No.

Page No.

1.1 Figure 1.1 UWB spectral mask for indoor

communication systems

2

1.2 Flow chart of research methodology 6

2.1 Comparison of the spectrum allocation for different

wireless radio systems

11

2.2 A secure UWB transceiver block diagram 12

3.1 Interface of NI Multisim 11.0 showing the transient

simulation tools

18

3.2 The schematic diagram of designed circuits: PRNG

using LFSR, DSSS modulator and UWB Avalanche

pulse generator

21

3.3 The whole system block diagram 22

3.4 24 bit of LFSR circuit 23

3.5 An example of simulation output of PRN code c(t), data

stream d(t anddata modulated by PRN v(t) running in

50us/Div time base and 10V/Div amplitude

24

3.6 Avalanche transistor output characteristics chart

25

3.7 Schematic circuit of UWB Avalanche pulse generator

using 2N5551 transistor

26

4.1 Pseudo Random Noise (PRN) sequence generated by 24

–bit LFSR (underside) and clock pulses (upside)

40

4.2 Simulation results of keying process: PRN code

(upside), data stream (middle) and PRN code modulated

by data signal (underside)

41

4.3 Time period measurement of PRNK and data signal 42

4.4 The UWB pulse train generated by using 30pF

Avalanche capacitor

43

xii

4.5 A single inverted Gaussian monocycle pulse of UWB

pulse generated by using 30pF Avalanche capacitor

43

4.6 The waveforms of input trigger signal (underside) and

collector output signal (upside)

44

4.7 A single inverted Gaussian monocycle pulse generated

by using 1.5pF Avalanche capacitor

45

4.8 A single inverted Gaussian monocycle pulse generated

by using 15pF Avalanche capacitor

45

4.9 The transition from narrowband to UWB in the

frequency domain

48

4.10 The power spectrum density of narrowband, spread

spectrum and UWB signal

49

4.11 Power spectral density of data signal with dBm

magnitude

50

4.12 Power spectral density of data signal with voltage

magnitude

50

4.13 Power spectral density of PRN sequence 51

4.14 Power spectral density of DSSS modulated signal 51

4.15 Power spectral density of UWB signal using 30pF

Avalanche Capacitor

52

4.16 Power spectral density of UWB signal using 15pF

Avalanche Capacitor

53

4.17 Power spectral density of UWB signal using 1.5pF

Avalanche capacitor

53

xiii

LIST OF ABBREVIATIONS

BJT Bipolar Junction Transistor

BPSK Binary Phase Shift Keying

CMOS Complementary Metal Oxide Semiconductor

Div. Division

DPSK- DSSS Differential Phase Shift Keying –Direct Sequence Spread

Spectrum

DS-CDMA Direct Sequence - Code Division Multiple Access

DSSS Direct Sequence Spread Spectrum

dB Decibel

dBm Mili-decibel

EDA Electronic Design Automation

erfc complementary error function

FCC Federal Communications Commission

FHSS Frequency Hopping Spread Spectrum

GPS Satellite Positioning System

IEEE Institute of Electrical and Electronics Engineers

igmc incomplete gamma function

LFSR Linear Feedback Shift Register

MANET Mobile ad hoc Network

NI National Institute

NIST National Institute of Standards and Technology

PAM Pulse Amplitude Modulation

PN Pseudo Number

PPM Pulse Position Modulation

PRNK Pseudo Random Noise Key

PRNG Pseudo Random Noise Generator

PSD Power Spectral Density

PSK Phase Shift Keying

RFID Radio Frequency IDentification

RNG Random Number Generator

SRD Step Recovery Diodes

THSS Time Hopping Spread Spectrum

UWB Ultra Wideband

WiMax Worldwide Interoperability for Microwave Access

WSA Weighted Switching Activity

XOR Exclusive OR gate

xiv

LIST OF SYMBOLS

α Common base current gain

σ Standard deviation

µ Mean

π 3.14159…unless defined otherwise for a specific test

Ω Resistance unit (Ohm)

𝛴 The summation symbol

Σ2

Variance

χ2 The chi-square distribution

χ2

(obs) The chi-square statistics computed on the observed value.

ε The original input string of zero and one bits to be tested

εi ith

bit in the original sequence

BVCBO Collector-base breakdown voltage

C Capacitor

F Capacitance unit (Farad)

fn The sum of the log2 distances between matching L-bit template

i Current

iB Base current

iC Collector current

K The number of degrees of freedom

L The length of each block

Li Length of the shortest Linear Feedback Shift Register sequence that

generate all bits in the block i

log(x) The natural logarithm of x: log(x) = loge(x) = ln x

xv

M Miller Avalanche multiplication coefficient

M The number of bits in a substring (block) to be tested.

m Semiconductor constant

N The number of M-bit blocks to be tested

n Length of the length testing bit string

Q The number of blocks in the initialization sequence

R Resistor

RL Load resistor

rb Data rate

rc Chip rate

Sn The nth

partial sum for values Xi = (-1,+1)

Sobs Absolute value of the sum of the Xi

Tj Table entry corresponding to the decimal representation of the content

of the ith

L-bit block

V Voltage (volt)

VCC IC power supply pin

Vc Collector output signal

Vcc Common collector voltage

VCE Voltage between collector and emitter

Vi Input signal

Vi The frequencies of the pattern

Vn The expected number of runs that would occur in sequence of length n

Vn(obs) The observed number of runs that would occur in sequence of length n

Xi The elements of the string consisting of ±1 that is to be tested

1

CHAPTER ONE

INTRODUCTION

1.1 BACKGROUND

Ultra Wideband (UWB) is a technology for use in short-distance communication of

data with an element of reliability. It consists of streaming of short pulses embedded

with data and produced by step or pulse excited-antennas or filters for a carrier free

communication. The UWB style of communication offers the advantages of high

speed data transmission with a very low power operation. Transmitting a large amount

of digital data over a wide spectrum of UWB in a secure fashion can be accomplished

by using some data embedding features (modulation) coupled with encryption

techniques. The methods such as spread spectrum, time and frequency modulation

schemes as well as multiplexing are reported and being discussed in recent reports

(Bobby, 2012; Long and Peng, 2011; Leon et al., 2004). While making sure a perfect

match between data items and the bits used for encryption, the use of cryptography

techniques based on generating high performance of random numbers increases the

reliability of the UWB systems.

UWB signals are used for commercial operation in the unlicensed frequency

band of 7500 MHz (3.1 – 10.6 GHz) with maximum emission power of -41 dBm per

MHz as per the specification released by the Federal Communications Commission

(FCC) on February 2002. (Roberto and Gerald, 2003).The illustration of the UWB

spectral mask for indoor communication systems as shown as in figure 1.1

below.(Roberto and Gerald, 2003). The announcement has opened many opportunities

for UWB potential applications in such short range and high speed wireless

communication including Radio Frequency IDentification (RFID), vehicular

2

monitoring and tracking systems, short range positioning system and handheld

outdoor applications in peer to peer mode operation without location restriction.

Figure 1.1 UWB spectral mask for indoor communication systems

The researchers in UWB area are actively reporting on issues such

improvement of system on signal generation, security enhancement, power

consumption, transmission speed, and enhancement of transceiver designs. Those

issues are necessary and could be chained together in order to make sure the resulting

system is able to meet the specifications of UWB regulation. In an article by Roberto

and Gerald (2003) stated that the emerging trends of UWB is a solution for the IEEE

802.15.3a (TG3a) standard which provides specification for a low complexity, low

power consumption and high data rate wireless connectivity. As for a security purpose

variety of modulation schemes should be properly selected to meet the different

design parameters for different applications. For instance, in a recent reported work by

Bobby (2012) Differential Phase Shift Keying –Direct Sequence Spread Spectrum,

called DPSK- DSSS for short, is being used for UWB transceiver modulation and

3

demodulation technique with Bi-phase modulation for recovering original input.

Another related work by Leon et al. (2004) is using Direct Sequence - Code Division

Multiple Access (DS-CDMA) technique for providing enhanced multiple access

capacity in mobile communication system. Both papers have proven that spread

spectrum technique is the most favorable choice and option for indoor wireless

communication applications.

Another aspect that should be the focus in security issues is the Pseudo

Random Noise Sequence generation or what is known as the spreading code sequence

(key) in spread spectrum applications. Linear Feedback Shift Register (LFSR) is the

most reliable method for generating pseudo random number in cryptographic key

generation algorithms. Having good statistical properties, low implementation cost,

low complexity and high speed rates are the reasons of wider acceptance of its usage

(Faheem et al., 2012). However, the enhancement of mathematical algorithms could

improve the performance of Pseudo Random Number Generator (PRNG). As reported

by Rahimov et al. (2011) proposes a combination chaotic equation for LFSR operation

that can produce a longer period of random sequence and improve the linear property

of LFSR.

The recent works by Long and Peng. (2011) and Bobby (2012) are most

preferable approaches when applied correctly to this research methodology. In another

published work by Long and Peng (2011) they proposed another technique of spread

spectrum which is Time Hopping Spread Spectrum (THSS) to be employed in UWB

communication system to improve the PSD performance of UWB Binary Phase Shift

Keying (BPSK) modulation schemes. The analysis of transceiver circuit design and its

performance is verified using spread spectrum modulation technique for UWB

wireless local area network using simulink model of DPSK DSSS transceiver. With

4

proper chosen of PN sequence generator and matching filters the circuit is

successfully used for transmitting and recovering of data messages with acceptable

accuracy.

This research is inclined towards on security area by choosing Direct Sequence

Spread Spectrum (DSSS) technique to be used in secure UWB wireless

communication systems with its own architecture of circuitry components such as 24

bits of PRNG and Avalanche UWB pulse generator. The system is managed to

maintain the operation in desirable low power. The theoretical explanation of how the

system works is provided and then matched by the simulation results of our sample

data transmission in UWB mode. At the end of work, we expect to show that the

spectral density validation has satisfied the UWB regulation specification

requirements better than other reported related works. We also emphasize the strength

of our transmitter is satisfied by evaluating the NIST randomness tests results. The

techniques of secure data transmission in the Ultra Wideband (UWB) wireless

communication application are increasingly discussed and reported. Most authors

agree that pseudo random key generation technique and data encoding technique are

most important considerations. Similar to the narrowband technology, UWB allows a

modulation scheme for data encoding technique applied in the system including

spread spectrum modulation.

1.2 PROBLEM STATEMENT

For a secured UWB communication system, the need for high quality of randomness

of key sequence generated by Pseudo Random Noise Generator (PRNG) is a challenge

for researchers as the sequence is only said to be random only if it is passes a number

5

of statistical tests. 24- bits of LFSR that used in this research work can provide a

sufficiently long period of key sequence and passes all the randomness tests.

Meanwhile, for a UWB system which adopts Direct Sequence Spread

Spectrum technique (DSSS) for data encoding purpose, it is important to clarify a

fundamental different between UWB communication and spread spectrum such their

bandwidth allocation. Therefore, the need of proper component operation in the

transceivers is essential to allocate the appropriate bandwidth for data signal during

transmission. As a solution, Avalanche UWB pulse generator has been proposed to

generate the nanosecond pulses of UWB signals in the Gigahertz bandwidth spectrum.

The shorter pulse duration and lower pulse amplitude is desirable for high speed and

low power communication. As the result, its Power Spectral Density (PSD) would

satisfy the UWB FCC mask spectrum. The lower magnitude of PSD would promise

the covert communication. Meanwhile, at the same time our system is making use of

the potentials of spread spectrum technique and UWB technology advantages such

high strength of security, low power, low cost and high speed of UWB wireless

communication application.

1.3 RESEARCH SCOPE

This research is based on the idea of using Direct Sequence Spread Spectrum (DSSS)

principle into a secure UWB communication system with its own architecture of

circuitry components such as 24 bits of PRNG and Avalanche UWB pulse generator.

Theoretical explanation of how the system is working is provided which is validated

by the simulation results of sample data transmission in UWB mode at the transmitter

side. Our work covers the evaluation using the NIST randomness tests results only.

However, immunity of our system against possible attacks (such as jamming, hacking

6

and blocking) of our data transmission is out of the scope of this thesis and are left for

future work.

1.4 RESEARCH METHODOLOGY

Figure 1.2 Flow chart of research methodology

E

ERRORS & JUSTIFICATION

RESULTS & ANALYSIS

1) Simulation Results

2) Randomness test evaluation

3) Effect of component values

4) Spectral Density validation

5) Benchmarking

TEST

Randomness test by NIST test suites

TECHNIQUES (SIMULATION)

1) PRN sequence generation by 24 bit LFSR

2) Data modulation by DSSS technique

3) UWB data signal generation by Avalanche transistor circuit

MODEL (SIMULATION)

1) Pseudo Random Number Generator (PRNG) of 24 bit LFSR

2) Direct Sequence Spread Spectrum (DSSS ) modulator

3) AvalancheUWB pulse generator circuit

PROBLEMS IDENTIFICATION

Literature survey and critical review of papers for identifying problem to be address

7

1.5 RESEARCH OBJECTIVES

The research work is aimed at investigating and developing aspects of proposed data

transmission technique with application in secure UWB communication. The main

objectives of the research work are as follow;

1. To design the Pseudo Random Noise Key Generator (PRNG) for a secure

UWB communication system.

2. To employ the Direct Sequence Spread Spectrum (DSSS) technique for a low

power UWB communication system.

3. To analyze the performance of Avalanche UWB pulse generator.

4. To test the randomness of proposed PRNG

1.6 THESIS OUTLINES

Chapter one has given the knowledge for the reader on what are the research all about,

the problem issues that we want to improve and the rationale of performing this

project.

Chapter two is very informative sources to review the researcher’s ideas and

approaches on solving the problems issues such security, power consumption and so

on. It is starting from general discussion on the work, narrowing it to the focus of

work in this research while passing through less and less general contemporary work,

ultimately zooming in more and much related research work for bench-marking

purpose.

Chapter three is provided with the information of the experimental tools

involved in this research work including circuit simulation, pseudo randomness test

and the specification of the components used for future reference. The UWB

transmitter design is thoroughly detailed by explaining the mechanism of the proposed

8

system. The experimental work is done by following the procedure and the results are

collected according to the flow of experiment. Last but not least, the algorithm and

computation for randomness tests of Pseudo Random Noise (PRN) sequence are

performed and justified.

Chapter four is about analysis of the simulation results of the designed circuits.

The result signals discussed step by step according to the system flow. The effect of

tunable values parameter such of Avalanche UWB pulse generator is observed. Lastly,

we validated the PSD of each signal going through in the design system to be in the

proper specification. The UWB pulse generated, Power Spectral Density (PSD) and

NIST statistical test result are compared with other related work.

Chapter five is a conclusion of the whole thesis and results obtained. Some

recommendation for future work is also stated in this last chapter.

9

CHAPTER TWO

LITERATURE REVIEW

This chapter provides the summary of the secure UWB communication background

including the key generation and its function, the encryption and decryption

technique, and the UWB pulse generation technique. Several contemporary works are

discussed on their general description, technique used, the result obtained and the

comparison of obtained result to other related work. The further discussion continued

by reviewing the much related work and ending with benchmarking.

2.1 BACKGROUND OF SECURE UWB COMMUNICATION

A communication between two authorized parties is said to be secure only if the

information transmitted is protected against any attempts by unauthorized parties to

capture, modify or block the transmitted information. (Denning, 1983; Scheneir, 1996;

Menezes, Oorschots and Stone, 1997). They state that securing wireless

communication requires a secret key generation and the same key (symmetric

encryption) or associated key (asymmetric or public-key encryption) is being used by

transmitter and receiver for encryption and decryption purpose. Basically, random

noise is used as a source signal for devices in a system to build up those keys to secure

the information data. Pseudo Random Number Generator (PRNG) is a common key

generator used in data communication that generates sequence of random binary

numbers. The sequence is said as pseudo random only if it passes a number of

statistical tests.

Linear Feedback Shift Register (LFSR) is the most preferable method for

generating pseudo random noise in cryptographic algorithm. Faheem, Shadab and