Patent ID: 11876898
Assignee: DENSO CORPORATION
Field: Digital communication (Electrical engineering)
Classification: CPC H  G | IPC H

Claim 0:
1. A vehicle master device comprising:
a data communication module that is mounted in a vehicle, the data communication module receives update data and rewrite specification data from outside of the vehicle via a wireless communication network; and
a central gateway that is mounted in the vehicle, and the central gateway includes one or more computers;
wherein:
the data communication module communicates the rewrite specification data and the update data to the central gateway via a first communication bus inside of the vehicle;

the central gateway communicates the update data to a rewrite target electronic control unit of a plurality of electronic control units via a second communication bus inside of the vehicle;
the one or more computers of the central gateway are programmed to:
acquire the rewrite specification data each time one of the plurality of electronic control units is updated either at the same time as acquisition of the update data or prior to acquisition of the update data;
analyze the rewrite specification data;
store a plurality of decryption keys for generation of corresponding security access keys, the access keys used to perform device authentication of the plurality of rewrite target electronic control units, the stored plurality of decryption keys being unreadable from outside of the central gateway and each decryption key of the plurality of decryption keys corresponding to a respective electronic control unit of the plurality of electronic control units;
extract a key derivation value corresponding to the rewrite target electronic control unit from an analysis result of the rewrite specification data, the key derivation value being generated outside of the vehicle;
select a decryption key corresponding to the rewrite target electronic control unit from the stored plurality of decryption keys;
decrypt the extracted key derivation value using the selected decryption key;
generate a security access key based on the decrypted extracted key derivation value; and
authenticate the rewrite target electronic control unit using the access key; and
after successful authentication of the rewrite target electronic control unit with the security access key, the central gateway distributes the update data to the rewrite target electronic control unit and instructs the rewrite target electronic control unit to rewrite a program.