A method and device is able to authenticate a subscriber of a digital mobile radiotelephone system vis-à-vis an authentication entity, wherein the subscriber firstly initializes vis-à-vis the authentication entity by executing several times the authentication algorithm containing stored subscriber-specific components and by storing the corresponding response parameters of the subscriber-specific components in a non-volatile memory. Systematic authentication of the subscriber of the mobile radiotelephone system vis-à-vis the authentication entity via a common interface is made possible by the authentication parameters stored in the memory since the authentication entity can always refer back to the response parameters of the individual subscriber module it already knows.