Computer Security: Principles and Practice Overview and Cryptographic Tools

Question 1
Which of the following is an example of an active security threat? (1.3)
A. Monitoring network traffic flow and activity
B. Recording details of file accesses and activity
C. Masquerading as an authorised user of a computer system
D. Intercepting and storing email messages

Question 2
Which of the following is not in the categories of security services. (1.5)
A. Data confidentiality
B. Availability service
C. Access control
D. Nonrepudiation
E. Secure data transmission
F. Authentication

Question 3
How many keys are required for Person A to communicate to Person B via a symmetric cipher? (2.2)
A. One secret key, identically held by each person
B. Two secret keys, one held by each person
C. Two keys, one being a private key and the other being a public key
D. One public key, identically held by each person

Question 4
What is a message authentication code? (2.5)
A. An authenticator that is a cryptographic function of the data (message) to be authenticated.
B. An authenticator that is a cryptographic function for operating system warning messages
C. An authenticator that is a cryptographic function of both the data (message) to be authenticated and the secret key used to encypt the data.
D. An authenticator that is a cryptographic function of the secret key used to encypt the data (message)

Question 5
What are the principal ingredients of a public-key cryptosystem? (2.8)
A. Plaintext and encryption algorithm.
B. Secret key
C. Public / private keys, ciphertext and decryption algorithm.
D. Both B and C.
E. Both A and C.
F. Both A and B.

Question 6
What is a digital signature? (2.11)
A. A digital signature is an authentication mechanism that enables the creator of a message to attach a code that acts as a signature.
B. A digital signature is an encryption mechanism that enables the creator of a message to attach a code that acts as a signature.
C. A digital signature is a scanned signature image file that the creator attaches to a message to prove it was sent .by the author.
D. A digital signature is an enbeded HTML tag that enables the creator of a message to attach a code that acts as a signature.











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Question 1
Which of the following is an example of an active security threat? (1.3)
Correct Answer: C. Masquerading as an authorised user of a computer system

Question 2
Which of the following is not in the categories of security services. (1.5)
Correct Answer: E. Secure data transmission

Question 3
How many keys are required for Person A to communicate to Person B via a symmetric cipher? (2.2)
Correct Answer: A. One secret key, identically held by each person

Question 4
What is a message authentication code? (2.5)
Correct Answer: C. An authenticator that is a cryptographic function of both the data (message) to be authenticated and the secret key used to encypt the data.

Question 5
What are the principal ingredients of a public-key cryptosystem? (2.8)
Correct Answer: E. Both A and C.

Question 6
What is a digital signature? (2.11)
Correct Answer: A. A digital signature is an authentication mechanism that enables the creator of a message to attach a code that acts as a signature.