scope:

The present document aims to study the introduction of an optional, user-centric authentication layer on top of the existing subscription authentication, supporting various authentication mechanisms and interactions with external authentication systems as well as a degree of confidence (i.e. a value that allows differentiated service policies depending on the reliability of the User Identifier).

The new authentication layer shall not replace existing subscription credentials. The security and privacy of subscriber or end user data shall not be compromised.

Use cases are developed and potential requirements derived how to use the new User Identifier within the 3GPP system e.g. to provide customized services and enhanced charging and how to provide this identifier to external entities to enable authentication for systems and services outside 3GPP.

Use cases for use within 3GPP include

- providing different users using the same UE with customized services

- identifying users of devices behind a gateway with a 3GPP subscription, but without the devices having a dedicated 3GPP subscription

- using a User Identifier being linked to a subscription to access 3GPP services via non-3GPP access

- using a User Identifier for slice authorization.