Cisco Certified Network Associate (CCNA) Practice Exam

What characterizes the CHAP authentication method in PPP?

1. It uses a single password sent in clear text

2. It requires a clear text password to be sent first

3. It utilizes a three-way handshake and hashes passwords

4. It generates a random session key for encryption

The correct answer is: It utilizes a three-way handshake and hashes passwords

The CHAP (Challenge Handshake Authentication Protocol) authentication method in PPP (Point-to-Point Protocol) is characterized by its use of a three-way handshake process combined with hashing for secure password handling. When a connection is established, CHAP uses a challenge-response mechanism where the server sends a challenge to the user. The user then responds with a value calculated by hashing their password along with the challenge. This process enhances security by ensuring that the actual password is never transmitted over the network, as only the hash is sent. This method effectively prevents replay attacks and ensures that even if the authentication exchanges are intercepted, the original passwords remain secure. The three-step handshake contributes to this security, providing a dynamic way of validating the identity of the user without exposing sensitive information.