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

Claim 11:
12. A vehicle master device comprising:
a predetermined electronic control circuit that includes one or more computers and is mounted in the vehicle, the predetermined electronic control circuit being communicably connected with a data communication module, the data communication module receives update data and rewrite specification data from outside of the vehicle via a wireless communication network;
wherein:
the predetermined electronic control circuit receives the rewrite specification data and the update data from the data communication module via a first communication bus inside the vehicle;
the predetermined electronic control circuit communicates the update data to a rewrite target electronic control circuit of a plurality of electronic control circuits via a second communication bus inside the vehicle;
the one or more computers of the predetermined electronic control circuit is programmed to:
acquire the rewrite specification data either at the same time as acquisition of the update data or prior to acquisition of the update data each time one of the plurality of electronic control circuits is updated;
analyze the rewrite specification data;
store a plurality of decryption keys for generation of corresponding security access keys, the security access keys used to perform device authentication of the plurality of electronic control circuits, the stored plurality of decryption keys being unreadable from outside of the predetermined electronic control circuit and each decryption key of the plurality of decryption keys corresponding to a respective electronic control circuit of the plurality of electronic control circuits;
extract a key derivation value corresponding to the rewrite target electronic control circuit from an analysis result of the rewrite specification data, the key derivation value being generated outside the vehicle;
select a decryption key corresponding to the rewrite target electronic control circuit from the stored plurality of decryption keys;
decrypt the extracted key derivation value using the selected decryption key;
generate a security accesses key based on the decrypted extracted key derivation value; and
authenticate the rewrite target electronic control unit using the security access key;
wherein, after the device authentication of the rewrite target electronic control circuit with the security access key succeeds, the predetermined electronic control circuit distributes the update data to the rewrite target electronic control circuit and instructs the rewrite target electronic control circuit to rewrite a program.