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SY0-501 · Question #226

Which of the following AES modes of operation provide authentication? (Select two.)

The correct answer is A. CCM C. GCM. CCM and GCM are both AES modes of operation that provide authenticated encryption, meaning they ensure both data confidentiality and authenticity.

Submitted by stefanr· Mar 4, 2026General security concepts

Question

Which of the following AES modes of operation provide authentication? (Select two.)

Options

  • ACCM
  • BCBC
  • CGCM
  • DDSA
  • ECFB

How the community answered

(37 responses)
  • A
    81% (30)
  • B
    11% (4)
  • D
    5% (2)
  • E
    3% (1)

Why each option

CCM and GCM are both AES modes of operation that provide authenticated encryption, meaning they ensure both data confidentiality and authenticity.

ACCMCorrect

CCM (Counter with CBC-MAC) is an authenticated encryption with associated data (AEAD) mode that combines the Counter mode for encryption with the CBC-MAC mechanism for authentication and integrity.

BCBC

CBC (Cipher Block Chaining) mode only provides confidentiality and does not offer any inherent authentication or integrity checks.

CGCMCorrect

GCM (Galois/Counter Mode) is an authenticated encryption with associated data (AEAD) mode that uses the Counter mode for encryption and a Galois field multiplier for authentication and integrity.

DDSA

DSA (Digital Signature Algorithm) is a public-key cryptographic algorithm used for digital signatures to ensure authenticity and non-repudiation, but it is not an AES mode of operation.

ECFB

CFB (Cipher Feedback) mode only provides confidentiality and lacks any built-in mechanism for authentication or integrity verification.

Concept tested: AES Authenticated Encryption Modes

Source: https://learn.microsoft.com/en-us/dotnet/api/system.security.cryptography.aesgcm

Topics

#AES modes#authenticated encryption#GCM#CCM

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