Gce Model Questions Vol1 2025 Computer Studies Question 13

Practice objective / multiple choice question 13 from the 2025 Gce Model Questions Vol1 Computer Studies examination.

Gce Model Questions Vol1 2025 Computer Studies Objective / Multiple Choice Medium Difficulty
Question 13 GCE_MODEL_QUESTIONS_VOL1 • 2025 • COMPUTER_STUDIES • objective

A symmetric‑key algorithm uses a 128‑bit key. An attacker can test \(10^9\) keys per second.\n(a) How many seconds, on average, would it take to brute‑force half of the key space?\n(b) Convert this time to years (use \(1\) year = \(3.15576\times10^{7}\) seconds).\n(c) If a security policy requires a minimum resistance of 5 years, does the 128‑bit key meet the requirement?

Answer Options

A. No; the key provides about \\\\(5.4\\\times10^{21}\\\) seconds of resistance, which is far below 5 years.
B. Yes; the key provides about \\\\(5.4\\\times10^{19}\\\) years of resistance, above 5 years but far less than claimed.
C. No; the key provides only \\\\(5.4\\\times10^{3}\\\) years of resistance, which is below the requirement.
Correct Answer D. Yes; the key provides about \(5.4\times10^{21}\) years of resistance, far above 5 years.
Correct Answer
D
Correct Option:
Yes; the key provides about \(5.4\times10^{21}\) years of resistance, far above 5 years.

About This Question

This is Gce Model Questions Vol1 2025 Computer Studies Question 13. It is one of the objective questions from the 2025 Gce Model Questions Vol1 Computer Studies examination.

Difficulty level: Medium .

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