All of the following are valid cryptographic hash functions EXCEPT:

A.
RIPEMD.

B.
RC4.

C.
SHA-512.

D.
MD4.

Explanation:
RC4 is not a hash function. RC4 is popular with wireless and WEP/WPA encryption.
Incorrect Answers:
A: The RACE Integrity Primitives Evaluation Message Digest (RIPEMD) algorithm was based on MD4
hashing algorithm.
C: The Secure Hash Algorithm (SHA) was designed to ensure the integrity of a message. SHA is a one-way
hash that provides a hash value that can be used with an encryption protocol. This algorithm produces a
160-bit hash value. SHA-2 has several sizes: 224, 256, 334, and 512 bit.
D: The Message Digest Algorithm (MD) also 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.

Dulaney, Emmett and Chuck Eastton, CompTIA Security+ Study Guide, 6th Edition, Sybex, Indianapolis,
2014, pp. 251, 255-256