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Difficulty: EasyCryptographic Concepts and Algorithms

Match each cryptographic mechanism to its primary operational security objective.

  • Key StretchingRepeatedly executing an algorithm to increase computational cost and impede offline brute-force attempts.
  • Password SaltingAdding unique random bytes to credentials prior to hashing to prevent precomputed rainbow table attacks.
  • Perfect Forward SecrecyGenerating unique ephemeral session keys so that compromising a long-term key does not decrypt past sessions.
  • Homomorphic EncryptionEnabling mathematical processing directly on encrypted data without needing to decrypt it first.

Answer

Key Stretching matches with repeatedly executing an algorithm to increase computational cost and impede offline brute-force attempts. Password Salting matches with adding unique random bytes to credentials prior to hashing to prevent precomputed rainbow table attacks. Perfect Forward Secrecy matches with generating unique ephemeral session keys so that compromising a long-term key does not decrypt past sessions. Homomorphic Encryption matches with enabling mathematical processing directly on encrypted data without needing to decrypt it first.
Each cryptographic technique aligns with a distinct operational goal: Key stretching increases computational difficulty against offline cracking; Password salting defeats precomputed hash lookups; Perfect Forward Secrecy protects recorded historical traffic using ephemeral keys; Homomorphic encryption enables calculations on ciphertexts without exposing plaintext.

Step-by-Step Solution

1
Identify the purpose of Key Stretching.
Key stretching algorithms (such as PBKDF2 or bcrypt) iterate a cryptographic hash function thousands of times to add execution overhead.
This directly increases computational cost for attackers performing offline brute-force attacks.
2
Identify the purpose of Password Salting.
Salting prepends or appends unique random bits to passwords before computing their digests.
This guarantees unique hash outputs for identical passwords, neutralizing precomputed rainbow table lookups.
3
Identify the purpose of Perfect Forward Secrecy.
Perfect Forward Secrecy uses ephemeral key exchange algorithms (like ECDHE) to generate distinct session keys for every communication session.
This ensures that compromise of a long-term private key does not compromise past encrypted sessions.
4
Identify the purpose of Homomorphic Encryption.
Homomorphic encryption allows third parties to compute operations directly on ciphertexts.
This enables secure data analysis in untrusted environments without decrypting data to plaintext.

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Cryptographic Concepts and Algorithms
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Cryptographic Concepts and Algorithms

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