Designing Cisco Enterprise Networks (ENSLD) — Question 225

Which AES mode should be used in a Cisco SD-WAN environment that includes multicast applications?

Answer options

• A. Electronic Code Book (ECB)
• B. Cipher Feedback (CFB)
• C. Cipher Block Chaining (CBC)
• D. Galois/Counter Mode (GCM)

Correct answer: C

Explanation

Cipher Block Chaining (CBC) mode is suitable for multicast applications because it provides confidentiality by ensuring that identical plaintext blocks produce different ciphertexts. Conversely, Electronic Code Book (ECB) mode has significant security vulnerabilities as it does not obscure data patterns, while Cipher Feedback (CFB) and Galois/Counter Mode (GCM) are less optimal for situations where the order of blocks matters, making CBC the best choice here.