August 1999
SC223 : COMPUTER SECURITY

QUESTION 1 (Compulsory)

Total Marks: 20 Marks

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SUGGESTED SOLUTIONS
Solutions and allocated marks are indicated in green.
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(a) Explain the characteristics of computer intrusion. [2]
In any system, the weakest point is the most vulnerable. One can expect an intruder to use any available means of penetration.

 
(b) Explain briefly the purpose of a public key protocol. [2]
Used between communicating entities to authenticate systems. Also used to hide the messages.

 
(c) Identify any two major goals of legal issues in computer security. [2]
  • Protection of code and data
  • Protection of access to programs
  • Protection of computing against criminals

 
(d) Name the two basic methods by which a system can provide security. [2]
System Access Controls (1 mark) and Data Access Controls.

 
(e) Identify and explain any two categories of vulnerabilities in PC security. [4]
  • User responsibility
  • Improper procedure for use
  • Hardware concerns
  • Software concerns

 
(f) List three advantages and one disadvantage of conducting a disaster simulation. [4]
Advantages:
  • Ensure that employees are aware of the plan and are able to response to it.
  • Test whether the backup arrangement is working effectively.
  • Results are useful for subsequent evaluation to enhance the plan.

 
(g) List and explain the different forms of non-repudiation services provided in networks. [4]
Nonrepudiation with proof of origin: proof of origin is provided to the recipient of the message. Nonrepudiation with proof of delivery: proof of delivery is provided to the sender of a message.