Examkin

Question

Difficulty: MediumCryptographic Concepts and Algorithms

A security analyst is reviewing the transport layer cryptographic configuration for a high-security financial microservice. The service requirements dictate that even if an adversary compromises the server's long-term private key in the future, previously intercepted session traffic must remain unencrypted and unreadable. Which cryptographic mechanism should be implemented to satisfy this requirement?

  1. Perfect Forward Secrecy utilizing ephemeral key exchange mechanisms such as ECDHEAnswer
  2. B
    Symmetric bulk data encryption using AES-256 in Cipher Block Chaining (CBC) mode
  3. C
    Cryptographic hash functions using SHA-256 to ensure data integrity
  4. D
    Static RSA certificate generation via a Certificate Signing Request to a trusted CA

Answer

Perfect Forward Secrecy utilizing ephemeral key exchange mechanisms such as ECDHE
The correct option specifies Perfect Forward Secrecy (PFS) with ephemeral key exchange (such as ECDHE). PFS ensures that session keys are generated dynamically for each communication session and deleted afterwards. Even if an attacker obtains the server's long-term private key in the future, they cannot calculate past session keys or decrypt previously intercepted traffic.

Step-by-Step Solution

1
Analyze the core security requirement stated in the scenario
Identified requirement: Protecting past recorded traffic from decryption if long-term server private keys are compromised in the future.
This requirement specifically describes the property of Perfect Forward Secrecy (PFS).
2
Evaluate cryptographic mechanisms against the PFS requirement
Ephemeral Diffie-Hellman key exchanges (e.g., ECDHE) generate temporary, single-session keys that are discarded after use, ensuring that compromised long-term private keys cannot decrypt past sessions.
Static key exchange algorithms (like RSA static exchange) decrypt secrets directly using the long-term private key, failing the requirement.
3
Select the option that implements ephemeral key exchange
The option specifying Perfect Forward Secrecy utilizing ephemeral key exchange mechanisms (ECDHE) directly fulfills the requirement.
It prevents retrospective decryption of intercepted communication streams.

Key Concept

Perfect Forward Secrecy (PFS) and Ephemeral Key Exchange
Rate this question

Topics

Cryptographic Concepts and Algorithms

More questions from this topic