Authenticating and Permitting Remote Access Copyright  2002 Microsoft Corporation. All Rights Reserved. Windows 2000 Authentication Protocols Windows   2000 Authentication Protocols The following table describes the authentication protocols and their encryption levels. Protocol Supports Encryption level Microsoft Challenge Handshake Authentication Protocol (MS- CHAP).Uses challenge response authentication. All Windows-based operating systems for VPN and dial-up connections. Medium Microsoft Challenge Handshake Authentication Protocol version 2 (MS-CHAP v2). Uses stronger data encryption keys and different encryption keys for sending and receiving. All Windows-based operating systems for VPN connections. Windows 2000 and Windows NT operating systems for dial-up connections. High CHAP Uses industry-standard Message Digest 5 (MD5). All Microsoft-based operating systems and many non-Microsoft- based operating systems. Medium Extensible Authentication Protocol (EAP).Supports a framework for highly secure authentication plug-in components. Windows 2000 operating systems and some non-Microsoft-based operating systems. High Password Authentication Protocol (PAP).Uses plain text passwords. All Microsoft-based operating systems and many non-Microsoft- based operating systems Low . Reserved. Windows 2000 Authentication Protocols Windows   2000 Authentication Protocols The following table describes the authentication protocols. Medium Extensible Authentication Protocol (EAP).Supports a framework for highly secure authentication plug-in components. Windows 2000 operating systems