Tachograph, Toll Onboard Unit, Display Instrument, and System

The system as claimed in claim 14, wherein the communication partners are configured to transmit the cryptographic check value and the associated payload data separately from one another, in at least one respective message.

A tachograph, comprising

• a data interface configured as a vehicle data bus interface, such that data communication takes place with at least one communication partner via a vehicle data bus, to which the tachograph and the respective communication partner are coupled, the tachograph is configured to
• determine a cryptographic check value as a function of payload data, for transmission via the data interface to the respective at least one communication partner, and to transmit the cryptographic check value in addition to the payload data to the respective communication partner, and
• receive the payload data and the cryptographic check value associated with the payload data, via the data interface, from the respective at least one communication partner, and to check the received payload data for corruption, based at least in part on the received cryptographic check value.

A toll onboard unit comprising:

• a data interface configured as a vehicle data bus interface, such that data communication takes place with at least one communication partner via a vehicle data bus, to which the toll onboard unit and the respective communication partner are coupled, and which toll onboard unit is configured to
• determine a cryptographic check value as a function of payload data, for transmission via the data interface to the respective at least one communication partner, and to transmit the cryptographic check value in addition to the payload data to the respective communication partner, and
• receive the payload data and the cryptographic check value associated with the payload data, via the data interface, from the respective at least one communication partner, and to check the received payload data for corruption, based at least in part on the received cryptographic check value.

A display instrument, comprising:

• a data interface configured as a vehicle data bus interface, such that data communication takes place with at least one communication partner via a vehicle data bus, to which the toll onboard unit and the respective communication partner are coupled, and which toll onboard unit is configured to
• determine a cryptographic check value as a function of payload data, for transmission via the data interface to the respective at least one communication partner, and to transmit the cryptographic check value in addition to the payload data to the respective communication partner, and
• receive the payload data and the cryptographic check value associated with the payload data, via the data interface, from the respective at least one communication partner, and to check the received payload data for corruption, based at least in part on the received cryptographic check value (PW).