SIT202 Computer Networks
ASSIGNMENT 2
This assignment is worth 15% of your final unit grade.
Due on 5, September, 2011 (9.00 am)
Total: 60 points
This assignment is designed to test, your basic understanding of computer networks through problem solving, s
SIT281 2013 TRIMESTER 2
ASSIGNMENT 1 SOLUTIONS
1. Simon works in a government office where encrypted messages are regularly
received. He knows that an affine cipher is the standard method of encryption used
by the office, and has access to the machine whi
CHAPTER 16
Elliptic Curves
In the mid1980s, Miller and Koblitz introduced elliptic curves into cryptography, and Lenstra
showed how to use elliptic curves to factor integers. Since that time, elliptic curves have played
an increasingly important role in
SIT281 2013 TRIMESTER 2
ASSIGNMENT 2 SOLUTIONS
Due: Friday September 27, 2013 at 12 noon (Australian Eastern Standard
Time)
Value: 20% of your final mark in the unit.
NO EXTENSIONS allowed without medical or other certification.
LATE ASSIGNMENTS will auto
CHAPTER 8
Hash Functions
8.1 Hash Functions
A basic component of many cryptographic algorithms is what is known as a hash function.
When a hash function satisfies certain noninvertibility properties, it can be used to make many
algorithms more efficient.
SIT202 Computer Networks
ASSIGNMENT 3
This assignment is worth 15% of your final unit grade.
Due on 5, October, 2011 (9.00 am)
Total: 50 points
This assignment is designed to test, your basic understanding of computer networks through problem solving, sim
SIT281 INTRODUCTION TO CRYPTOGRAPHY 2016 TRIMESTER 2
PRACTICAL SESSION 7
In this practical, we examine some of the properties of the encryption scheme AES and we apply
some of the AES components. We also examine the nonlinearity property of AES.
Use your
SIT281 Introduction to Cryptography
WEEK 2
Deakin University CRICOS Provider Code: 00113B
Lecture objectives
In this lecture:
We look at examples of substitution ciphers.
We see how block ciphers work.
Deakin University CRICOS Provider Code: 00113B
Substi
SIT281 Introduction to Cryptography
Week 9
Deakin University CRICOS Provider Code: 00113B
Objectives
We discuss hash functions, what they are used for and
how they are constructed.
We also examine hash collisions.
We see how to use hash functions to encry
WORKED PROBLEMS CHAPTERS 8, 12 AND 16
CHAPTER 8
8.8
4. 4. The probability that no two have birthdays in the same month is
(1 1/12)(1 2/12)(1 3/12) =
165/288 0.573.
6 a and b.
(a) The probability is (1/2)j that we succeed on the jth try, so the
expected nu
SIT281 INTRODUCTION TO CRYPTOGRAPHY 2016 TRIMESTER 2
PRACTICAL SESSION 9
In this weeks practical, we look at authentication in RSA schemes, we examine
the discrete logarithm problem and we get some practice with the Baby Step
Giant Step algorithm for brea
SIT281 Introduction to
Cryptography
Week 4
Deakin University CRICOS Provider Code: 00113B
Objectives
In this lecture we cover sections 3.5, 3.6, 3.7 and 3.9.
The topics we study are:
Modular Exponentiation
Theorems of Fermat and Euler
Primitive roots
Deak
SIT281 Introduction to
Cryptography
Week 6
Deakin University CRICOS Provider Code: 00113B
Objectives
This lecture introduces you to the most recent encryption
standard, Rijndael.
We examine in particular the various mathematical
components on which it is
SIT 281 Introduction to
Cryptography
Week 7
Deakin University CRICOS Provider Code: 00113B
Objectives
We examine the concept of a public key and how this
differs from systems such as DES and AES which use
symmetric (private) keys.
We study the RSA public
SIT 281 INTRODUCTION TO
CRYPTOGRAPHY
WEEK 8
Deakin University CRICOS Provider Code: 00113B
Objectives
This week we cover Sections 6.7, 7.1 and 7.2.2.
This includes:

a look at general public key cryptosystems
the concepts of authentication and nonrepudia
SIT 281 Introduction to
Cryptography
WEEK 3
Deakin University CRICOS Provider Code: 00113B
Objectives
We cover sections
3.1,
3.2,
3.3
and
3.4
Deakin University CRICOS Provider Code: 00113B
Modular arithmetic
Of course, we saw that the Caesar cipher an
Example: the plain text CAT using the affine function y=5x+12
C
2
A >
T
0
A B C DZ
19
0123
25
Encrypt letter C
Y= 5x + 12
= 5(2) + 12
= 22 equal W
CAT = WMD
Find the decription function :

1/5(mod 26) = t
Make x subject of function :
1/5 = t (mod 26) >
SIT 281 Introduction to
Cryptography
Week 10
Deakin University CRICOS Provider Code: 00113B
Objectives
This lecture is based on Chapter 12 of the text.
The objective is to build a scheme in which a secret (or
piece of information) can be shared among seve
SIT281 Introduction to
Cryptography
Week 11
Deakin University CRICOS Provider Code: 00113B
Objectives
In this final week of new material, we examine a very
widely used cryptographic system.
It is based on a geometric system called elliptic curves.
We will
SIT281 INTRODUCTION TO CRYPTOGRAPHY 2016
TRIMESTER 2
PRACTICAL SESSION 10
In this weeks practical, we discuss collisions applying the birthday attack, look
at the hash function SHA1 and use hash functions in encrypting.
Your textbook will be useful. Also
SIT281 INTRODUCTION TO CRYPTOGRAPHY 2016
TRIMESTER 2
PRACTICAL SESSION 5
In this practical we apply the FLT and Eulers Theorem in working questions
involving square roots, primitive roots, finding inverses, and the 3pass protocol.
You will need your text
SIT281 INTRODUCTION TO CRYPTOGRAPHY 2016 TRIMESTER 2
PRACTICAL SESSION 6
In this practical, we get some practice on components of the encryption scheme DES. In the first
part of the practical, we examine the initial permutation. In the second part, we app
SIT281 INTRODUCTION TO CRYPTOGRAPHY 2016
TRIMESTER 2
PRACTICAL SESSION 2 WEEK 2
In this practical class, we use Maple to assist in decrypting some texts based on affine
and Vigenere ciphers and frequency analysis.
It would be useful to have your textbook
SIT281 INTRODUCTION TO CRYPTOGRAPHY 2016
TRIMESTER 2
PRACTICAL SESSION 3
In the first part of this practical, we examine the Hill cipher.
In the second part of this practical class, we focus on LFSRs.
You might find it useful to have your textbook handy a
SIT281:Cryptography
Assign # 1
Due: 12/8/2016
1.
(a). Using the a ne function Ee (x) = 5x + 8 mod 26 encipher the
plain text "its cool".
(b). Determine the corresponding decryption function.
2.
(a). Using the Hill method with matrix M =
3
1
6
mod 26 encry
SIT281 INTRODUCTION TO CRYPTOGRAPHY 2016 TRIMESTER 2
PRACTICAL SESSION 8
This practical is based on the RSA scheme. You will get some experience with encrypting and
decrypting in the scheme. You will also see how Shannons ideal of confusion and diffusion
SIT281 INTRODUCTION TO CRYPTOGRAPHY 2016 TRIMESTER 2
PRACTICAL SESSION 4
This practical deals with problems based on the Euclidean Algorithm (see part A) and
on the Chinese Remainder Theorem (see part B).
A. The Euclidean Algorithm
1. (a) Using Maple, fin