What is the RESULT of a hash algorithm being applied to a message?

A.
A digital signature

B.
A ciphertext

C.
A message digest

D.
A plaintext

Explanation:
A cryptographic hash function is a hash function which is considered practically impossible to invert, that is, to
recreate the input data from its hash value alone.
The input data is often called the message, and the hash value is often called the message digest or simply the
digest.
Incorrect Answers:
A: To create a digital signature, a message digest is calculated (by the hash algorithm being applied to the
message) then it is encrypted with the sender’s private key. However, the digital signature is not the direct
output of the hash algorithm being applied to the message.
B: A ciphertext is the output of an encryption algorithm, not a hash algorithm being applied to data.
D: A plaintext is the message ‘before’ the hash algorithm is applied to the message; it is the input to the hash
algorithm, not the output.

https://en.wikipedia.org/wiki/Cryptographic_hash_function
Krutz, Ronald L. and Russel Dean Vines, The CISSP Prep Guide: Mastering the Ten Domains of Computer
Security, John Wiley & Sons, New York, 2001, p. 151