Definition of CHAP
The IETF developed the challenge handshake authentication protocol(CHAP), It is a PPP authentication protocol. It is used when the link first starts up. Additionally, it runs routine checks to see if the router is still in contact with the same host. CHAP is a three-step process of exchange of shared a secret. where the password authentication protocol(PAP) uses a two-way handshake for authentication between the remote user and the PPP server. It offers more security than PAP due to the variable nature of the value to determine the hash value.