What algorithm has been selected as the AES algorithm, replacing the DES algorithm?

A.
RC6

B.
Twofish

C.
Rijndael

D.
Blowfish

Explanation:
After DES was used as an encryption standard for over 20 years and it was cracked in a relatively short time
once the necessary technology was available, NIST decided a new standard, the Advanced Encryption
Standard (AES), needed to be put into place. In January 1997, NIST announced its request for AES candidates
and outlined the requirements in FIPS PUB 197. AES was to be a symmetric block cipher supporting key sizes
of 128, 192, and 256 bits. The following five algorithms were the finalists:
MARS Developed by the IBM team that created Lucifer
RC6 Developed by RSA Laboratories
Serpent Developed by Ross Anderson, Eli Biham, and Lars Knudsen
Twofish Developed by Counterpane Systems
Rijndael Developed by Joan Daemen and Vincent Rijmen
Out of these contestants, Rijndael was chosen. The block sizes that Rijndael supports are 128, 192, and 256
bits.
Rijndael works well when implemented in software and hardware in a wide range of products and
environments. It has low memory requirements and has been constructed to easily defend against timing
attacks.
Rijndael was NIST’s choice to replace DES. It is now the algorithm required to protect sensitive but unclassified
U.S. government information.
Incorrect Answers:
A: RC6 was a finalist; however, Rijndael was selected by NIST as the AES algorithm.
B: Twofish was a finalist; however, Rijndael was selected by NIST as the AES algorithm.
B: Blowfish was not selected by NIST as the AES algorithm.

Harris, Shon, All In One CISSP Exam Guide, 6th Edition, McGraw-Hill, 2013, p. 809