Section: 5.1.2 Entity authentication
Content: The following security features related to entity authentication are provided: - user authentication: the property that the serving network corroborates the user identity of the user; - network authentication: the property that the user corroborates that he is connected to a serving network that is authorised by the user's HE to provide him services; this includes the guarantee that this authorisation is recent. To achieve these objectives, it is assumed that entity authentication should occur at each connection set-up between the user and the network. Two mechanisms have been included: an authentication mechanism using an authentication vector delivered by the user's HE to the serving network, and a local authentication mechanism using the integrity key established between the user and serving network during the previous execution of the authentication and key establishment procedure. Clause 6.3 describes an authentication and key establishment mechanism that achieves the security features listed above and in addition establishes a secret cipher key (see 5.1.3) and integrity key (see 5.1.4) between the user and the serving network. This mechanism should be invoked by the serving network after a first registration of a user in a serving network and after a service request, location update request, attach request, detach request or connection re-establishment request, when the maximum number of local authentications using the derived integrity key have been conducted. Clause 6.5 describes the local authentication mechanism. The local authentication mechanism achieves the security features user authentication and network authentication and uses an integrity key established between user and serving network during the previous execution of the authentication and key establishment procedure. This mechanism should be invoked by the serving network after a service request, location update request, attach request, detach request or connection re-establishment request, provided that the maximum number of local authentications using the same derived integrity key has not been reached yet.