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EC-Council

312-50V9 · Question #302

Todd has been asked by the security officer to purchase a counter-based authentication system. Which of the following best describes this type of system?

The correct answer is C. An authentication system that creates one-time passwords that are encrypted with secret keys. A counter-based authentication system (HOTP) generates one-time passwords by applying a cryptographic HMAC function to a shared secret key combined with an incrementing counter.

System Hacking

Question

Todd has been asked by the security officer to purchase a counter-based authentication system. Which of the following best describes this type of system?

Options

  • AA biometric system that bases authentication decisions on behavioral attributes.
  • BA biometric system that bases authentication decisions on physical attributes.
  • CAn authentication system that creates one-time passwords that are encrypted with secret keys.
  • DAn authentication system that uses passphrases that are converted into virtual passwords.

How the community answered

(61 responses)
  • A
    2% (1)
  • B
    3% (2)
  • C
    90% (55)
  • D
    5% (3)

Why each option

A counter-based authentication system (HOTP) generates one-time passwords by applying a cryptographic HMAC function to a shared secret key combined with an incrementing counter.

AA biometric system that bases authentication decisions on behavioral attributes.

This describes behavioral biometrics such as keystroke dynamics or gait recognition, which is unrelated to counter-based OTP systems.

BA biometric system that bases authentication decisions on physical attributes.

This describes physical biometrics such as fingerprint or iris scanning, which is unrelated to counter-based OTP systems.

CAn authentication system that creates one-time passwords that are encrypted with secret keys.Correct

Counter-based authentication, standardized as HOTP (RFC 4226), creates one-time passwords by computing HMAC-SHA1 over a shared secret key and a synchronized event counter. Each successful authentication increments the counter, ensuring each password is valid for only one use and cannot be replayed.

DAn authentication system that uses passphrases that are converted into virtual passwords.

This describes a passphrase-to-virtual-password conversion scheme, which is a different mechanism from counter-based OTP generation using cryptographic keys and counters.

Concept tested: Counter-based one-time password (HOTP) authentication

Source: https://www.rfc-editor.org/rfc/rfc4226

Topics

#OTP#counter-based authentication#MFA#token authentication

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