An electric wiring system of a motor vehicle with control devices that communicate with each other via a data bus, and with at least a first communication apparatus inside the vehicle for data exchange with a remote communication station outside the vehicle via a communication channel is provided. To make an authentication of the electric wiring system possible, the first remote communication station outside the vehicle transmits at least one cryptographic key and/or at least one certificate for storage in a first control device of the plurality of control devices via the communication channel to the communication apparatus inside the vehicle. The first control device stores the at least one key and/or the at least one certificate in coded or decoded form and the at least one key and/or the at least one certificate is/are used at least in the framework of an authentication.