Integrating User Customization and Authentication: The Identity Crisis

The integration of user customization with authentication follows four patterns. The local-user pattern tightly couples user authentication and customization. The external-user pattern loosely couples customization and authentication so that the customization module relies on the external authentication provider to authenticate users and return their unique identifiers. The local- + external-user pattern tightly couples customization to a local user account, but that account can be connected to multiple external authentication providers. Finally, the masked-external-user pattern requires extra effort to protect sensitive information about users' identity.