Which two statements about using the CHAP authentication mechanism in a PPP link are true?
(Choose two)
A.
CHAP users a two-way handshake
B.
CHAP authentication periodically occurs after link establishment.
C.
CHAP uses a three-way handshake
D.
CHAP authentication is performed only upon link establishment.
E.
CHAP authentication passwords are sent in plaintext.
F.
CHAP has no protection from playback attacks.