Maria works as a Network Security Officer for Gentech Inc. She wants to encrypt her network traffic.
The specific requirement for the encryption algorithm is that it must be a symmetric key block
cipher. Which of the following techniques will she use to fulfill this requirement?

A.
IDEA

B.
PGP

C.
DES

D.
AES

Explanation:
The Data Encryption Standard (DES) is a block cipher (a form of shared secret
encryption) that was selected by the National Bureau of
Standards as an official Federal Information Processing Standard (FIPS) for the United States in 1976
and which has subsequently enjoyed
widespread use internationally. It is based on a symmetric-key algorithm that uses a 56-bit key. The
algorithm was initially controversial with
classified design elements, a relatively short key length, and suspicions about a National Security
Agency (NSA) backdoor. DES consequently
came under intense academic scrutiny, which motivated the modern understanding of block ciphers
and their cryptanalysis.