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CAS-004 Practice Question: Which TWO of the following are valid techniques…
Which TWO of the following are valid techniques to mitigate the risk of side-channel attacks on cryptographic implementations? (Select exactly 2.)
⚠ Common exam trap
CompTIA CASP+ often tests the misconception that cryptographic strength (e.g., key length or random number generation) can prevent side-channel attacks, but these attacks exploit implementation flaws, not algorithmic weaknesses.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Implementing constant-time algorithms to avoid timing variations.
Constant-time cryptographic implementations ensure that the execution time does not depend on secret data, such as keys or plaintext. This directly mitigates timing side-channel attacks, where an attacker measures variations in execution time to infer secret values. By making all code paths take the same amount of time regardless of input, the attacker cannot exploit timing differences.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Obfuscating the source code of the cryptographic library.
Why it's wrong here
Obfuscation is a weak defense; it does not prevent side-channel attacks that analyze physical emissions.
- ✗
Using a cryptographically secure random number generator for key generation.
Why it's wrong here
CSPRNG is important for key unpredictability but does not address side channels during algorithm execution.
- ✓
Implementing constant-time algorithms to avoid timing variations.
Why this is correct
Constant-time code ensures that execution time does not depend on secret data, preventing timing attacks.
- ✗
Increasing the key length to 4096 bits.
Why it's wrong here
Key length affects brute-force resistance, not side-channel leakage that exploits timing or power.
- ✓
Adding noise to power consumption or using power analysis resistant logic.
Why this is correct
Noise and balanced logic can reduce the correlation between secret data and power consumption, mitigating power analysis attacks.
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Written by Johnson Ajibi, MSc IT Security
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This CAS-005 practice question is part of Courseiva's free CompTIA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the CAS-005 exam.