A security analyst discovered data such as images and word documents hidden within different types of
files. Which of the following cryptographic concepts describes what was discovered?

A.
Symmetric encryption

B.
Non-repudiation

C.
Steganography

D.
Hashing

Explanation:
Steganography is the process of concealing a file, message, image, or video within another file, message,
image, or video.
Note: The advantage of steganography over cryptography alone is that the intended secret message does
not attract attention to itself as an object of scrutiny. Plainly visible encrypted messages, no matter how
unbreakable will arouse interest, and may in themselves be incriminating in countries where encryption is
illegal. Thus, whereas cryptography is the practice of protecting the contents of a message alone,
steganography is concerned with concealing the fact that a secret message is being sent, as well as
concealing the contents of the message.
Incorrect Answers:
A: Symmetric-key algorithms are algorithms for cryptography that use the same cryptographic keys for
both encryption of plaintext and decryption of ciphertext.
B: Nonrepudiation prevents one party from denying actions they carried out.
D: A hash function is used to map digital data of variable size to digital data of fixed length.

Dulaney, Emmett and Chuck Eastton, CompTIA Security+ Study Guide, 6th Edition, Sybex, Indianapolis,
2014, pp. 249-252, 255, 262, 323
http://en.wikipedia.org/wiki/Steganography