Authentication
Authentication in computer systems uses application protocols to verify that the identity which is requesting access to a computing system is actually who they say they are. Common authentication protocols are OpenID, NTLM, Kerberos, PAP and CHAP. There is a long list of authentication protocols available, each one being applicable to different systems and scenarios. In the context of AAA (Authentication, Authorization and Accounting), authentication protocols work in association with authorization protocols to first identify the requesting identity (authentication) and then grant that identity with access and permissions to requested systems and applications (authorization).
