This Standard defines a MAC that employs a cryptographic hash function with a secret key.

This Standard defines a MAC that employs a cryptographic hash function with a secret key.

• A. FIPS 186-4 Digital Signature Standard
• B. SP 800-s7
• C. FIPS 180-4 Secure Hash Standard
• D. FIPS 198-1 Keyed-Hash Message Authentication Code (HMAC)

Answer: (D)

The standard that defines a Message Authentication Code (MAC) employing a cryptographic hash function with a secret key is the Keyed-Hash Message Authentication Code (HMAC), which is specified in FIPS 198-1. HMAC combines a cryptographic hash function with a secret key to produce a secure MAC, ensuring both the integrity and authenticity of a message. The process involves hashing the combination of the secret key and the message, providing a way to verify that the message has not been altered and that it originates from a legitimate source. This is crucial in the field of IT security, as it allows entities to ensure the authenticity of messages exchanged over potentially insecure communication channels. In contrast, other options may involve cryptographic standards or related protocols but do not specifically address the use of a cryptographic hash function combined with a secret key in the way that HMAC does. For example, the Digital Signature Standard pertains to digital signatures rather than message authentication codes.

The standard that defines a Message Authentication Code (MAC) employing a cryptographic hash function with a secret key is the Keyed-Hash Message Authentication Code (HMAC), which is specified in FIPS 198-1. HMAC combines a cryptographic hash function with a secret key to produce a secure MAC, ensuring both the integrity and authenticity of a message.

The process involves hashing the combination of the secret key and the message, providing a way to verify that the message has not been altered and that it originates from a legitimate source. This is crucial in the field of IT security, as it allows entities to ensure the authenticity of messages exchanged over potentially insecure communication channels.

In contrast, other options may involve cryptographic standards or related protocols but do not specifically address the use of a cryptographic hash function combined with a secret key in the way that HMAC does. For example, the Digital Signature Standard pertains to digital signatures rather than message authentication codes.