As a cybersecurity consultant for SafePath Corp, you have been tasked with implementing a system for secure email communication. The key requirement is to ensure both confidentiality and non…

Question

Options

• AUse symmetric encryption with the AES algorithm.
• BUse the Diffie-Hellman protocol for key exchange and encryption.
• CApply asymmetric encryption with RSA and use the public key for encryption.
• DApply asymmetric encryption with RSA and use the private key for signing.

• A
  14% (7)
• B
  6% (3)
• C
  2% (1)
• D
  78% (38)

Explanation

Explanation

Applying asymmetric encryption with RSA and using the private key for signing satisfies both requirements: the sender's private key creates a digital signature that proves authenticity and prevents denial (non-repudiation), while the recipient's public key can be used to encrypt the message for confidentiality - this combination is the foundation of secure email systems like S/MIME and PGP.

• Option A (AES symmetric encryption) provides confidentiality but offers no non-repudiation, since any party sharing the symmetric key could have created the message.
• Option B (Diffie-Hellman) is a key exchange protocol only - it establishes a shared secret but does not inherently provide encryption or digital signing for non-repudiation.
• Option C is partially correct but incomplete - encrypting with a public key ensures confidentiality, but anyone can use a public key, so it provides no proof of who sent the message (no non-repudiation).

Memory Tip: Think "Private = Proof" - only you hold your private key, so signing with it proves it was you (non-repudiation). Public keys are for locking (encrypting), private keys are for proving (signing).

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