Question

Difficulty: MediumCryptographic Concepts and Algorithms

A security engineer is updating enterprise cryptographic standards across various operational systems. Match each cryptographic algorithm or mechanism on the left to its primary operational security capability on the right.

  • Galois/Counter Mode (AES-GCM)Provides authenticated encryption by delivering simultaneous bulk data confidentiality and data integrity verification.
  • Elliptic Curve Diffie-Hellman Ephemeral (ECDHE)Establishes temporary session keys dynamically to ensure perfect forward secrecy during network transport.
  • Password-Based Key Derivation Function 2 (PBKDF2)Applies salting and repeated hashing iterations to slow down offline password cracking and dictionary attacks.
  • Hash-based Message Authentication Code (SHA-256 HMAC)Combines a symmetric secret key with a cryptographic hash function to verify data origin authentication and payload integrity.

Answer

Galois/Counter Mode (AES-GCM) pairs with authenticated encryption for bulk data confidentiality and integrity; Elliptic Curve Diffie-Hellman Ephemeral (ECDHE) pairs with temporary session key negotiation for perfect forward secrecy; Password-Based Key Derivation Function 2 (PBKDF2) pairs with salting and repeated iterations for password cracking mitigation; SHA-256 HMAC pairs with secret-key hashing for origin authentication and payload integrity.
Each cryptographic primitive aligns strictly with its defined operational role: AES-GCM performs authenticated bulk encryption, ECDHE manages ephemeral key exchange for perfect forward secrecy, PBKDF2 performs key stretching to secure stored passwords, and SHA-256 HMAC provides keyed integrity and origin verification.

Step-by-Step Solution

1
Evaluate Galois/Counter Mode (AES-GCM)
Identified as an authenticated encryption cipher mode.
GCM mode pairs symmetric encryption with built-in authentication tag generation to achieve confidentiality and integrity simultaneously.
2
Evaluate Elliptic Curve Diffie-Hellman Ephemeral (ECDHE)
Identified as an ephemeral key exchange protocol.
The ephemeral nature of ECDHE key generation ensures independent session keys, establishing perfect forward secrecy.
3
Evaluate Password-Based Key Derivation Function 2 (PBKDF2)
Identified as a password hashing and key stretching function.
PBKDF2 introduces salt and thousands of pseudorandom iterations to slow down dictionary and brute-force cracking attempts on stored credentials.
4
Evaluate SHA-256 HMAC
Identified as a keyed message authentication mechanism.
HMAC combines a shared secret key with the SHA-256 hash function to confirm message integrity and authenticate sender origin.

Key Concept

Cryptographic Primitives and Operational Capabilities
Estimated Time:1m 30s
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