3.7 - Understand Methods of Cryptanalytic Attacks CISSP Practice Questions (Page 7)

Questions 31–35

1. 31foundation · easy

   What is the primary characteristic of a brute force attack against a cryptographic key?

   • AIt intercepts the key during the key exchange process.
   • BIt exploits mathematical weaknesses in the algorithm to reduce the key space.
   • CIt systematically tries every possible key until the correct one is found.
   • DIt uses a precomputed table of hashes to reverse a key quickly.
   Reveal Solution Discussion Select an answer first
2. 32foundation · easy

   In a ciphertext-only attack, what information does the attacker have access to?

   • AThe ability to choose ciphertexts and see their decryptions
   • BThe encryption key
   • COnly intercepted ciphertext
   • DBoth plaintext and ciphertext pairs
   Reveal Solution Discussion Select an answer first
4. 33foundation · easy

   Why is a brute force attack considered computationally infeasible against a strong cryptographic key?

   • AStrong keys are protected by law from being guessed.
   • BStrong keys change automatically every second, preventing exhaustive search.
   • CThe key space is so large that the time and resources required to try all keys are prohibitive.
   • DStrong keys are stored in hardware security modules that cannot be accessed.
   Reveal Solution Discussion Select an answer first
5. 34expert · hard

   A security team is testing a legacy encryption service that decrypts data submitted via an API. The team has the ability to submit arbitrary ciphertexts and receive the corresponding plaintext. They suspect the service uses a weak block cipher mode. Which attack would be most effective to exploit this capability?

   • AChosen-ciphertext attack, submitting crafted ciphertexts to the decryption oracle to recover the key
   • BKnown-plaintext attack, using the API documentation that shows sample plaintext-ciphertext pairs
   • CFrequency analysis, analyzing the distribution of ciphertexts submitted to the API
   • DTiming attack, measuring the response time of the API to infer key bits
   Reveal Solution Discussion Select an answer first
6. 35expert · hard

   A security researcher is analyzing a smart card used for authentication. The researcher has the card and a card reader, and can control the power supply to the card. The goal is to extract the secret key stored on the card. Which attack is most appropriate?

   • AFault injection attack, introducing voltage glitches to cause erroneous cryptographic outputs that reveal the key
   • BCiphertext-only attack, intercepting encrypted communications from the card
   • CKerberoasting, requesting service tickets to crack the key
   • DRansomware attack, encrypting the card's data and demanding payment
   Reveal Solution Discussion Select an answer first