JAVA/Sun Exam Questions

Which two statements about the digest and mac commands are true?

Which two statements about the digest and mac commands are true?
(Choose two.)

A.
The mac command can use the Digital Encryption Standard (DES) in cipher-block chained (CBC) mode. The digest command can NOT.

B.
The mac command uses a distinct class of hash functions called message authentication codes (MACs). MAC functions combine the input file with a key supplied by the user, returning a fixed length digest.

C.
The mac command uses a distinct class of hash functions called MACs. A MAC function combines the input file with a randomly generated salt, and returns a digest.

D.
The digest command requires that the user supply a key. The mac command does NOT. The digest command takes an input file, combines it with the key, and a variable length digest is returned.