Which of the following are restricted to 64-bit block sizes? (Select TWO).

A.
PGP

B.
DES

C.
AES256

D.
RSA

E.
3DES

F.
AES

Explanation:
B: The Data Encryption Standard (DES) has been used since the mid-1970s. It was the primary
standard used in government and industry until it was replaced by AES. It’s based on a 56-bit key
and has several modes that offer security and integrity. It is now considered insecure because of
the small key size.
E: Triple-DES (3DES) is a technological upgrade of DES. 3DES is still used, even though AES is
the preferred choice for government applications. 3DES is considerably harder to break than many
other systems, and it’s more secure than DES. It increases the key length to 168 bits (using three
56-bit DES keys).