ITEC852 Assignment 2017: Security Solutions and Analysis

This document presents solutions to the ITEC852 Assignment 2017, focusing on various aspects of computer security. The solutions address the Slammer code's attack, analyzing its exploitation of port 1434 and replication methods. The assignment explores cryptography concepts, including a key-based encryption method, and discusses the impact of ciphertext changes on plain text integrity. It also covers dictionary attacks, offering countermeasures to enhance security. Furthermore, the document delves into the concept of pseudo-randomness in generating PINs, contrasting it with hashing and algorithmic approaches. Finally, the assignment analyzes the security implications of different processor models, comparing the vulnerability of two-processor and four-processor systems, and discussing the benefits of native operating system support. The document references key sources like Mell and Grance (2011) and Bishop (2005).

ITEC852 Assignment 2017
Question 1
Since the slammer codes attack exploits port 1434 and makes it to generate
IP addresses. It won’t spread to the entire system or IP addresses since the
UDP ports in which it replicates are secure.
Question 3
(a)
S e c u r I t y I S p e a c e O f M I n d key
security
18 4 2 20 17 8 19 24 18 4 2 20 17 8 19 24 18 4 2 20 20
36 8 4 4 40 34 16 48 29 22 17 24 17 10 13 28 23 16 10 33 20)26
K I e e o I q w d w r x r k n c x q k 7 u
Cipher text= kleeoIqwdwrxrkncxqk7u
(b). Since the substitution ratio of plain text to cipher text is 1:many.None of
the decrypted text will be affected.
(c)Dictionary attack is a method for defeating a cipher by finding its
paraphrase in many possibilities and trying to find which one can succeed
among them. The following can be used to make it infeasible.
Using Strong passwords against it.
Blocking of IPs that can attack the SSH.
(d). The size of the key bytes is 64bytes. The keystream is a repetition of the
initial key stream of length m. (1<m<=26).

Question 4
a) When decrypting a change in the cipher text will tamper or change the
two plain texts thus a single byte error will cause many errors in
transmission
b) i.
The system has
Decrypting which does the following.
C1=Dec(k)c6
ii. The text will have no meaning because there is exchange of the
decrypting and encrypting keys,
iii.
Presence of decrypting and encrypting keys.
Use of highly technical algorithms.
b. The system becomes weak since the encryption and the decryption
keys are the same. This means anybody with the key can be able to access
the information.

Question 5
(a)
Pseudo randomness-this selects the numbers randomly in a given criteria
to form pins.
Hashing this function that impossible to inverts hence produces pins in
mysterious way.
Algorithms-this are particular ways in which a functions select four digits
from digits.
Greedy pattern-this the pattern in which various pins are suggested for
given request.
(b)
Pseudo randomness
Min entropy=,max Xp(X);
Hashing
H..(X)=-LOG2 maxrPr{X=x}
Algorithms
H2(x)=-log2 maxPr{w}
Greedy pattern
Has none.
(c)
H..(X)= maxrPr{X=x}
H2(x)=maxPr{w}

Question 6
(a).-The two processor models have low chances of getting infected by
viruses than the four processor model
 The two processor model doesn’t support all the present applications
hence no update to the old software’s the current ones.
 Two processor only support 32 bit applications while 64bit support all
the applications.
 Two processor operating system had a high vulnerability of viruses
while the four processor has less vulnerability.
b. natively this allow the operating system to give the CPU chance to carry
out some processes.
c. this will allow the OS to support many application within the computer
platform on which is running.
d. This will make the computer platform to be very fast since the processes
do not collide due unavailability of spaces. Processes searche will
increase in speed and no regular hanging of the computer.

References
Mell, P. and Grance, T., 2011. The NIST definition of cloud computing.
Bishop, M.A., 2005. Introduction to computer security.