Methods and apparatus for generating a key radio base station and an authenticator identity terminal in a cellular radio system

A method for use in a radio base station in a radio system, acting as radio base source station to create a first authenticator identification terminal for identifying a user equipment, UE, connected to said base station radio, in which the UE communicates with said radio base station via a secure communication associated with an existing cryptographic key characterized by the steps of: - creating (303) said first authenticator terminal identity in response to a set bits known to both the UE to the radio base station, the terminal identity and the existing cryptographic key data, - distributing (205) said first authenticator terminal identity to a number of base stations target radio radio system to enable the identification of the UE in a radio base station destination, so that the UE identifies the destination base station comparing said first authenticator terminal identity with an authenticator corresponding terminal identity created in said UE in response to a set of known data bits for both the EU and the radio base station, the terminal identity and said cryptographic key existing, so that both the first authenticator terminal identity and the corresponding authenticator terminal identity is created in response to the terminal identity and the existing cryptographic key.