A user repository is in general terms a set of user credentials (optionally including user certificates and so on), with the possible addition of information such as the groups to which a user belongs, the user's address, telephone number and the email address. Often, an enterprise implements a central user repository that can be used by applications throughout a network to authenticate users; when a user tries to log in to an application, the application issues a request to the user repository to check whether the user credentials supplied are valid. Usually the user repository is created and maintained separately from the applications that use it.

A newly-installed CentraSite system is configured to authenticate users against an internal text file. This is intended to enable an administrator to log in and modify the configuration as required to meet enterprise requirements; typically, and in particular if you are working in a distributed environment, where one or more Application Server Tiers and a separate Registry/Repository are involved, an external repository such as Active Directory or LDAP will form the core of the authentication process.