Which of the following are legacy authentication protocols used within the stronger EAP authentication protocols? Each correct answer represents a complete solution. Choose all that apply.

A.
MS-CHAP

B.
PPTP

C.
PAP

D.
CHAP

Explanation:
A password authentication protocol (PAP) is an authentication protocol that uses a password. PAP is used by Point to Point Protocol to validate users before allowing them access to server resources. Almost all network operating system remote servers support PAP. Working cycle:
Client sends username and password. Server sends authentication-ack (if credentials are OK) or authentication-nak. Challenge Handshake Authentication Protocol (CHAP) is an authentication protocol that uses a secure form of encrypted authentication. Using CHAP, network dial-up connections are able to securely connect to almost all PPP servers. Microsoft Challenge Handshake Authentication Protocol version 2 (MS-CHAP v2) is the new version of MSCHAP. MS- CHAP v2 provides the highest level of security and encryption for dial-up connection in the environment consisting of both Windows NT and Windows 2000/XP dialup clients. It provides mutual authentication, stronger initial data encryption keys, and different encryption keys for sending and receiving datA.Answer option B is incorrect. Point-to-Point Tunneling Protocol (PPTP) is a remote access protocol. It is an extension of the Point-to-Point Protocol (PPP). PPTP is used to securely connect to a private network by a remote client using a public data network, such as the Internet. Virtual private networks (VPNs) use the tunneling protocol to enable remote users to access corporate networks securely across the Internet. PPTP supports encapsulation of encrypted packets in secure wrappers that can be transmitted over a TCP/IP connection.