1. A method of controlling access to elements within a bus system or network, comprising the following steps: an external device ( 100 ), which wishes to establish a communication link with the bus system or network, is identified by a device-specific identifier to a bus manager or network manager ( 300 ), and the device-specific identifier itself or a data record allocated to it contains information regarding the membership of the device in a certain class; authentication of the external device ( 100 ) is performed on the basis of a digital key; after authentication, the external device ( 100 ) is granted access to elements of the bus system or network in accordance with its class membership.