METHOD AND SERVER FOR PROVIDING A SPECIAL-PURPOSE KEY

摘要

The invention relates to a method for providing a special-purpose key for securing a data link between a mobile terminal (MS) and a network access server (NWZS) of an access network (ZNW). According to said method, once the mobile terminal (MS) is successfully authenticated via the network access server (NWZS) and via at least one authentication proxy server of an authentication signal path (ASP) a non-special purpose universal key (K) is generated by an authentication server (AS) of the mobile terminal (MS). A derived key is derived from said universal key by at least one authentication proxy server along the authentication signal path (ASP) or by the network access server (NWZS) depending on a character string (ZK), which has at least one respective binding criterion (BK). Said derived key forms the special-purpose key that has a special purpose defined by the binding criterion (BK).