Dependability and Security MCQs

Which of the following is not a Protection system ?

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A. System to stop a train if it passes a red light
B. System to indicate not returning of the library book
C. System to shut down a reactor if temperature/pressure are too high
D. None of the mentioned
✅ The correct answer is option B.
Explanation: A Protection system is a specialized system that is associated with some other control system, which can take emergency action if a failure occurs.

A password checking system that disallows user passwords that are proper names or words that are normally included in a dictionary is an example of ________________ with respect to security systems?

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A. risk
B. control
C. attack
D. asset
✅ The correct answer is option B.
Explanation: A control protective measure that reduces a system’s vulnerability.

Which of the following terms is a measure of the probability that the system will cause an accident ?

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A. Risk
B. Hazard probability
C. Accident
D. Damage
✅ The correct answer is option A.
Explanation: The risk is assessed by considering the hazard probability, the hazard severity, and the probability that the hazard will lead to an accident.

At which stage of risk analysis specification, the additional security requirements take account of the technologies used in building the system and system design and implementation decisions ?

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A. Preliminary risk analysis
B. Life-cycle risk analysis
C. Operational risk analysis
D. All of the mentioned
✅ The correct answer is option B.
Explanation: This risk assessment takes place during the system development life cycle after design choices have been made..

Which of the following is incorrect with respect to Model Checking ?

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A. Model checking is particularly valuable for verifying concurrent systems
B. Model checking is computationally very inexpensive
C. The model checker explores all possible paths through the model
D. All of the mentioned
✅ The correct answer is option B.
Explanation: Model checking is very expensive.It is only practical to use it in the verification of small to medium sized critical systems.

Controls that are intended to ensure that attacks are unsuccessful is analogous to ______________ in dependability engineering?

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A. Fault avoidance
B. Fault tolerance
C. Fault detection
D. Fault Recovery
✅ The correct answer is option A.
Explanation: In Fault avoidance the system is developed in such a way that human error is avoided and thus system faults are minimised.