MS-CHAP is the Microsoft version of the Challenge-handshake authentication protocol, CHAP. The protocol exist in two versions, MS-CHAPv1 (defined in RFC 2433) and MS-CHAPv2 (defined in RFC 2759). MS-CHAPv2 was introducted with Windows 2000.

Compared with CHAP, MS-CHAP:

MS-CHAPv2 provides mutual authentication between peers by piggybacking a peer challenge on the Response packet and an authenticator response on the Success packet.

= References =