ELEC5616 Computer and Network Security
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Edmund Tse 2010
IETF developed version 3.1, called Transport Layer Security (TLS)
Variable encryption key sizes 40 bit exportable, up to 256-bit AES
Designed to minimise load on browser, server and to support
ELEC 2103
Simulation &Numerical Solutions in
Engineering
Dr Alexander Kukushkin
Revision
Lecture 11
What will be the output from the following line of code?
> h=[-1 1 2];
h(h>=1)
a)
b)
c)
d)
e)
[0 1 2]
[0 1 1]
[1 2]
An error message
None of the above
What
ELEC 2103
Simulation &Numerical Solutions in
Engineering
Dr Alexander Kukushkin
Lecture 8
LU decomposition
Ax = b,
A = LU ,
Ux = y ,
Ly = b
U represents an upper triangular matrix, L is a lower triangular matrix.
A square matrix is called triangular if it
ELEC 2103
Simulation &Numerical Solutions in
Engineering
Dr Alexander Kukushkin
Lecture 7
Descriptive statistical quantities
MATLAB also provides the hist command to generate a histogram:
hist(y), where y is a vector containing the data. This form aggreg
ELEC 2103
Simulation &Numerical Solutions in
Engineering
Dr Alexander Kukushkin
Differential Equations
Lecture 9
An Ordinary Differential Equations ( ODE) represents a relationship between a function
and its derivatives, for instance
which is to hold for,
ELEC 2103
Simulation &Numerical Solutions in
Engineering
Dr Alexander Kukushkin
Linear Time Invariant Systems
Lecture 10
Linear time-invariant system (LTI)
Linear time-invariant system (LTI): a linear system in which parameters of the system
do not change
ELEC 2103
Simulation &Numerical Solutions in
Engineering
Dr Alexander Kukushkin
Revision-2
Lecture 12
Q1. Ellipse and parabola are described by the following equations:
+ =1 ,
= -2
After executing the following commands to find the points of intersectio
ELEC2103 Simulation & Numerical Solutions in Engineering - 2013
Laboratory 1 Getting Started with MATLAB
This laboratory presents some of the basics of MATLAB. It assumes no prior knowledge of
MATLAB but does assume a familiarity with PCs and basic mathem
ELEC2103 Simulation & Numerical Solutions in Engineering - 2013
Laboratory 3 More Programming in MATLAB
This laboratory continues the basics of programming in MATLAB started in laboratory 2. It is
designed to give you more practice in MATLAB programming.
ELEC2103 Simulation & Numerical Solutions in Engineering - 2013
Laboratory 2 Programming in MATLAB
This laboratory describes the basics of programming in MATLAB. Topics discussed include
M-files, control flow, structures and cell arrays, and more on graph
ELEC2103 Simulation & Numerical Solutions in Engineering - 2013
Laboratory 6 Probability, Statistics, and Data Analysis
This laboratory presents some of the MATLAB functions used in probability calculations, basic
statistics, and data analysis. Importantl
ELEC2103 Simulation & Numerical Solutions in Engineering - 2013
Laboratory 4 Symbolic Maths & Circuits 1
This laboratory is an introduction to the use of symbolic mathematics in MATLAB. It covers
the creation of symbolic objects, the plotting of symbolic
ELEC2103 Simulation & Numerical Solutions in Engineering - 2013
Laboratory 5 Laplace Transforms & Circuits 2; random
numbers.
This laboratory covers an introduction to the Laplace transform and continues with circuit
analysis from the last laboratory. The
ELEC2103 Simulation & Numerical Solutions in Engineering - 2013
Laboratory 9 Linear Time Invariant Systems
This laboratory is partly an introduction to basic concepts in linear time-invariant (LTI) systems
but its main purpose is to familiarise you with s
ELEC 2103
Simulation &Numerical Solutions in
Engineering
Dr Alexander Kukushkin
Revision-3
Lecture 13
Phase portraits of Linear Systems
Consider linear systems of the form
where
=
11
=
21
(1)
12
22
The entries of the coefficient matrix A are real constan
ELEC2103 Simulation & Numerical Solutions in Engineering - 2013
Laboratory 8 Differential Equations
This laboratory presents an introduction to ordinary differential equations (ODEs). The tools for
studying ODEs have changed greatly in the past decades. T
ELEC 2103
Simulation &Numerical Solutions in
Engineering
Dr Alexander Kukushkin
Lecture 5
THE PHASOR
A sinusoidal current or voltage at a given frequency is characterized
by its amplitude and phase angle.
=
A complex factor remains unchanged in linear
ELEC 2103
Simulation &Numerical Solutions in
Engineering
Dr Alexander Kukushkin
Lecture 6
Generation of Gaussian random variables
Central limit theorem
Sum of infinite number of random variables each having arbitrary statistical
distribution can be repres
ELEC5616 Computer and Network Security
Edmund Tse 2010
Network protocols
Overview of network security
Problems with vendor software
o Only hackers end up running network scanning tools
o Intrusion detection systems dont detect new attacks, and is poor at
ELEC5616 Computer and Network Security
o
o
o
o
o
Edmund Tse 2010
Bob Alice:
ACK(ISNA + 1), SYN(ISNB)
Alice Bob:
RST
# wasnt me!
Again, Mallory can use SYN flood to take down Alice to prevent her from tearing down
Mallory Alice:
SYN flood
Mallory Bob:
SYN(
ELEC5616 Computer and Network Security
Edmund Tse 2010
o
Alice and Trent share key KAT via the authentication server (by password)
Alice Trent:
A, B
Trent Alice:
cfw_TT, L, KAB, B, cfw_TT, L, KAB, AK_BTK_AT
Alice Bob:
cfw_TT, L, KAB, AK_BT, cfw_A, TAK_AB
ELEC5616 Computer and Network Security
Edmund Tse 2010
Wireless security
Wireless LAN vulnerabilities
o Physical access to the network is no longer required
o Most wireless networks are inside the firewall no more network perimeter
o Most wireless network
ELEC5616 Computer and Network Security
IPsec
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IPsec is the working group aiming at securing the Internet architecture (both IPv4 and IPv6).
The two main features of IPsec are:
Authentication Header (AH) for authentication and integrity
Tran
ELEC5616 Computer and Network Security
Edmund Tse 2010
E-Commerce protocols
E-Cash
o Cash hasnt really changed in the last thousand years not really suited for the Internet
o Cash continues to battle advances in counterfeiting
o Cash is pseudo-anonymous (
ELEC5616 Computer and Network Security
o
Edmund Tse 2010
TCP Header
Attacks
Packet sniffing
o Packet sniffing is the process of listening to raw network traffic (i.e. eavesdropping).
o Usually reveals a lot information because the Internet is mostly unenc
ELEC5616 Computer and Network Security
o
Edmund Tse 2010
Integrity check (IC) field
WEP uses CRC-32 for checksum
Good for detecting transmission errors, but cant stop malicious errors
CRCs are linear h(m k) = h(m) h(k), and it is independent of the mas
ELEC5616 Computer and Network Security
Edmund Tse 2010
o
a1at-1 (0 aj p-1), defining the polynomial
Trent computes yi = f(xi) mod p (1 xi p-1)
o just any random points on the curve
Trent sends a share (xi, yi) to user i
o Pooling of shares
Any t users c
ELEC5616 Computer and Network Security
Edmund Tse 2010
Hardware security
Tamper resistant devices are those that resist keys being extracted
Tamper evident devices are those that make key extraction obvious when checked
Common security features
o Faraday
ELEC5616 Computer and Network Security
Edmund Tse 2010
Anonymous cash protocol #2
o Protocol
Similar to protocol #1, except Alice attaches a unique into each anonymous money order
When merchant takes the money order to the bank, the bank verifies the si
ELEC 2103
Simulation &Numerical Solutions in
Engineering
Lecturer:
Tutors:
Dr Alexander Kukushkin
Loris Marini,
Mahyar Shirvanmoghaddam
Textbooks:
Major: Introduction to Matlab for Engineers, William J Palm, 3rd ed
(any edition)
Additional: Electrical Eng