Semester 2 Mock

Question 1

Encode the following message using the Caesar Cipher: ENCRYPTION

Answer 1

HQFUBSWLRQ

Question 2

What is the maximum number of unique keys available for use with AES?

Answer 2

???

Question 3

What is the block size associated with AES?

Answer 3

128 bits

Question 4

How many rounds does the AES encryption algorithm specify?

Answer 4

In AES the number of rounds is dependent on the key size, cycles of repetition are as follows:
● 10 cycles of repetition for 128-bit keys.
● 12 cycles of repetition for 192-bit keys.
● 14 cycles of repetition for 256-bit keys.

Question 5

How many sub-keys are generated when using AES?

Answer 5

???One for each round

Question 6

What is the purpose of the S-boxes in AES?

Answer 6

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Question 7

Calculate Φ(n) where p = 17 and q = 5
Detail your calculations
(3marks)

Answer 7

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Question 8

Explain how an electronic message can be made ‘non-refutable’.
(4 marks)

Answer 8

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Question 9

Encode the word BUISNESS using a Playfair cipher with a keyword of WORKER. Provide a detailed explanation for each stage of the encryption.
(10 marks)

Answer 9

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Question 10

Explain how secure a computationally secure cipher actually is.
(5 marks)

Answer 10

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Question 11

Decode the following message that has been encoded using a Rail Fence Cipher:
JEOILCL0ASNSSAE0MBDAOLD7

Answer 11

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Question 12

EXPLAIN HOW Message Authentication Codes (MACs) work, their usefulness, and the benefit of using HMACSs as an alternative.

Answer 12

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Question 13

Briefly describe each of the requirements that a public key cryptosystems must fulfil in order to be considered a secure algorithm.

Answer 13

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Question 14

Detail each of the major flaws in WEP’s encryption mechanism.

Answer 14

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Question 15

Detail the security issues associated with moving confidential business data from a business’s own local network to the Cloud.

Answer 15

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Question 16

List the additional security issues when using mobile phones for confidential business computing,

Answer 16

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Question 17

Compare and contrast the different types of firewall available outlining the strengths and weaknesses of each.

Answer 17

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Question 18

Describe THREE examples of intrusion attack.

Answer 18

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Question 19

Explain in detail how Pretty Good Privacy (PGP) can be used to ensure message authentication and non-repudiation but not confidentiality.
(10 marks)

Answer 19

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Question 20

Detail the two most important protocols associated with SSL/TLS.
(10 marks)

Answer 20

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