Question 1- CHAP/PAP

Question 0

List the stages of CHAP authentication.

Answer 0

Three-way handshake:
Challenge – a message is sent.
Response – a hash is applied to the message and it’s returned.
Accept/reject – the response is checked against the expected hash value.

Question 1

Explain the purpose of CHAP (challenge handshake authentication
protocol) and when it is used.

Answer 1

CHAP is used at the start-up of a link and periodically to verify the identity of the remote node.

Question 2

What is the main difference between PAP and CHAP?

Answer 2

PAP is not a strong authentication protocol and uses a two-way handshake. Passwords are sent across the link in clear text. CHAP uses a three-way handshake and provides protection against playback attack through the use of a variable challenge value that is unique and unpredictable.