The invention relates to a motor vehicle display apparatus having an electronic appliance containing: a first memory area (117) for storing data (109), wherein the data contain a motor vehicle license number, a second memory area (119) for storing at least one first certificate (178), a first interface (103) for receiving a first signal (109′) and a signature (111′, 113′) for the first signal from a transmitter (107′), means (123) for checking the validity of the signature of the first signal using the first certificate, means (139) for generating a second signal on the basis of the reception of the first signal, means (127) for actuating a display apparatus (136) to reproduce the data stored in the first memory area and to visually output the second signal, wherein the second signal is generated and/or output only if the signature is valid.