What do you mean by Authentication protocol?

Authentication means validating the identity of a user who needs to access a set of resources.

It is of two types

i)Password Authentication Protocol(PAP)

ii)Challenge Handshake Authentication Protocol(CHAP)

PAP is a two step process. The user sends a authentication identification and a password. The system determines the validity of the Information sent.CHAP is a three step process. The system sends a value to the user. The user manipulates the value and sends the result. The system Verifies the result.