Which of the following MUST Matt, a security administrator, implement to verify both the integrity and
authenticity of a message while requiring a shared secret?

A.
RIPEMD

B.
MD5

C.
SHA

D.
HMAC

Explanation:
HMAC (Hash-Based Message Authentication Code) uses a hashing algorithm along with a symmetric key.
The hashing function provides data integrity, while the symmetric key provides authenticity.
Incorrect Answers:
A: RIPEMD is a hashing function only and will not provide authenticity.
The RACE Integrity Primitives Evaluation Message Digest (RIPEMD) algorithm was based on MD4. There
were questions regarding its security, and it has been replaced by RIPEMD-160, which uses 160 bits.
B: MD5 is a hashing function only and will not provide authenticity.
The Message Digest Algorithm (MD) creates a hash value and uses a one-way hash. The hash value is used
to help maintain integrity. There are several versions of MD; the most common are MD5, MD4, and MD2.
C: SHA is a hashing function only and will not provide authenticity.
The Secure Hash Algorithm (SHA) was designed to ensure the integrity of a message.

Dulaney, Emmett and Chuck Eastton, CompTIA Security+ Study Guide, 6th Edition, Sybex, Indianapolis,
2014, pp. 139, 255, 260