Vehicle-External Device Authentication for Driving Automation Level Validation

The patent implements a nested certificate validation structure where the third certificate (combining vehicle and external device) contains references to both the first certificate (vehicle) and second certificate (external device). This nested validation approach allows the system to determine system-wide automation level by validating the outermost third certificate, which automatically verifies the embedded first and second certificates, thus simplifying the determination process while maintaining comprehensive validation.

The patent performs preliminary authentication actions by pre-establishing the first certificate for the vehicle and second certificate for the external device before they combine. When the external device attaches to the vehicle, the third certificate is generated that incorporates references to these pre-established certificates. This preliminary preparation simplifies the actual authentication process at combination time, as the validation authority can directly verify the pre-prepared certificate structure rather than performing complex real-time authentication.

The third certificate serves multiple functions simultaneously: it certifies the combination of vehicle and external device, references the validity of both first and second certificates, and enables determination of the system-wide driving automation level. By designing the third certificate to incorporate references to the first and second certificates rather than duplicating their full content, the system achieves precise automation level measurement while minimizing the quantity of certificate data that needs to be processed and stored.