Advanced Cryptography CAS-005 Practice Questions (Page 1)

Questions 1–5

1. 1expert · hard

   A security architect is designing a password storage system for a high-security government application. The system must resist offline brute-force attacks, including those that might be performed with quantum computers in the future. The architect is considering using a key stretching function. Which choice is most appropriate?

   • AUse bcrypt with a high cost factor and a 64-bit salt.
   • BUse PBKDF2 with a high iteration count and a 128-bit salt.
   • CUse Argon2id with parameters that require a large amount of memory and a high time cost.
   • DUse a simple SHA-256 hash with a long salt to minimize computational overhead.
   Reveal Solution Discussion Select an answer first
2. 2application · medium

   A company is evaluating whether to use a hardware security module (HSM) for its public-key infrastructure (PKI). The PKI issues certificates for a large number of servers and performs thousands of signing operations per day. Which benefit is most directly provided by the HSM?

   • AIt accelerates the RSA signing operations and protects the private keys from extraction.
   • BIt provides a software-based key management system that is easier to integrate with existing applications.
   • CIt eliminates the need for certificate revocation lists (CRLs).
   • DIt automatically renews certificates before they expire.
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4. 3application · medium

   A financial services company processes a high volume of TLS-encrypted transactions. The servers are experiencing high CPU utilization during peak hours, which is causing latency spikes. The company wants to reduce the CPU load without changing the application code. Which solution is most appropriate?

   • ADeploy a hardware security module (HSM) to offload TLS handshake operations.
   • BSwitch to a symmetric-only cipher suite to eliminate the need for public-key cryptography.
   • CReduce the TLS session timeout to force more frequent renegotiations.
   • DUse a software-based TLS accelerator that runs as a user-space process.
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5. 4foundation · easy

   In a homomorphic encryption scheme, what does the decrypted result of a computation performed on ciphertexts equal?

   • AThe ciphertexts re-encrypted with a new key
   • BThe result of the same computation performed on the original plaintexts
   • CThe plaintexts themselves without any modification
   • DA random value that cannot be predicted
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6. 5application · medium

   A cloud storage provider wants to offer a service where clients can search their encrypted files for keywords without the provider being able to read the contents. The provider is considering homomorphic encryption. Which limitation of current homomorphic encryption is most likely to affect this use case?

   • AHomomorphic encryption requires the client to share the decryption key with the provider.
   • BHomomorphic encryption is not secure against quantum attacks.
   • CHomomorphic encryption only supports addition, not multiplication, so it cannot be used for search.
   • DThe computational overhead is high, making search over large encrypted datasets slow.
   Reveal Solution Discussion Select an answer first