A home subscriber server (400) receives a request for authentication information from an authentication server (300) and transforms cryptographic keys for a user equipment (100) into access specific cryptographic keys based on an identity of an authenticator (200) controlling access from the user equipment (100) to an EPS network, and generates the authentication information including the access specific cryptographic keys and a separation indicator which is set. The user equipment (100) checks whether the separation indicator included in the authentication information is set, and if the separation indicator is set, transforms cryptographic keys into access specific cryptographic keys based on the identity of the authenticator (200), and computes a key specific to an authentication method from the access specific cryptographic keys.