Which type of handshake does CHAP authentication use to establish a PPP link?
A. one-way
B. two-way
C. three-way
D. four-way
Which type of handshake does CHAP authentication use to establish a PPP link?
Which type of handshake does CHAP authentication use to establish a PPP link?
A. one-way
B. two-way
C. three-way
D. four-way
The Challenge Handshake Authentication Protocol (CHAP) (defined in RFC 1994 leavingcisco.com) verifies the identity of the peer by means of a three-way handshake. These are the general steps performed in CHAP:
After the LCP (Link Control Protocol) phase is complete, and CHAP is negotiated between both devices, the authenticator sends a challenge message to the peer.
The peer responds with a value calculated through a one-way hash function (Message Digest 5 (MD5)).
The authenticator checks the response against its own calculation of the expected hash value. If the values match, the authentication is successful. Otherwise, the connection is terminated.
Here, we are not treating the chap subject, we are treating the CHAP in order to estabilish a PPP link,
To estabilish a ppp link we have two entities, we configure chap on the router per example and on the BAS/NAS,
Here we have not a one-way or two-way, we have 3-way,
I thik that the question focuses on this. There are 3 steps, so, 3-way.
My Bad. A one-way authentication is apparently not the same as a one-way handshake. C is right.
According to the source below, CHAP uses either one-way or (optionally) two-way handshake over PPP:
https://www.cisco.com/c/en/us/support/docs/wan/point-to-point-protocol-ppp/25647-understanding-ppp-chap.html
“Note: This example depicts a one-way authentication. In a two-way authentication, this entire process is repeated. However the calling router initiates the initial challenge.”