A subsystem, within a security system, designed to validate the identity of a user prior to granting access to resources. Validation can be in the form of user authentication or single sign-on (SSO). Inputs to authentication mechanisms include passwords and intelligent tokens. Upon successfully completing authentication, the authentication system issues a security token, which can be used by other security systems in the same security domain. Inputs to SSO mechanisms include security tokens generated by authentication systems in the same security domain.
