On-vehicle authentication system, communication device, on-vehicle authentication device, communication device authentication method and communication device manufacturing method

An on-vehicle authentication device for authenticating a plurality of electronic control units connected to the on-vehicle authentication device by a network inside a vehicle, the network being a plurality of communication lines, one of the plurality of electronic control units being a newly connected electronic control unit, the on-vehicle authentication device authenticating the newly connected electronic control unit, wherein the newly connected electronic control unit includes a first processor, and a first storage in which a first secret key and a first public key are stored, the on-vehicle authentication device comprising:

• a second processor, and
• a second storage in which a signature verification key for verifying the authenticity of an electronic signature attached to the first public key to be paired with the first secret key stored in the newly connected electronic control unit, a second secret key and a second public key are stored, wherein the second processor is configured to
• acquire the first public key attached with the electronic signature,
• perform verification using the signature verification key stored in the storage,
• encrypt the second public key stored in the storage using the first public key attached with the electronic signature having been determined to be authentic,
• transmit the second encrypted public key to the newly connected electronic control unit via the network,
• receive the first public key from the newly connected electronic control unit, the received first public key being encrypted by the first processor using the second public key,
• decrypt the encrypted first public key using the second secret key stored in the second storage, and
• determine whether the decrypted first public key is authentic, and
• authenticate that the newly connected electronic control unit is an authentic device in the case that the first public key is authentic.

A method for authenticating an electronic control unit, comprising:

• storing a first secret key and a first public key in the first storage of the electronic control unit connected to the network inside a vehicle,
• storing a second secret key, a second public key and a signature verification key for verifying the authenticity of an electronic signature attached to the first public key in the second storage of an on-vehicle authentication device connected to the network,
• acquiring, by the on-vehicle authentication device, the first public key attached with the electronic signature;
• verifying the authenticity of the electronic signature attached to the acquired first public key using the signature verification key stored in the second storage;
• encrypting the second public key stored in the second storage using the first public key attached with the electronic signature having been determined to be authentic by the verification;
• and transmitting the encrypted second public key to the electronic control unit via the network,
• receiving, by the electronic control unit, the encrypted second public key from the on-vehicle authentication device;
• decrypting the received second public key using the first secret key stored in the first storage;
• encrypting the first public key stored in the first storage using the decrypted second public key;
• and
• transmitting the encrypted first public key to the on-vehicle authentication device via the network, and
• receiving, by the on-vehicle authentication device, the encrypted first public key from the electronic control unit;
• decrypting the received encrypted first public key using the second secret key stored in the second storage;
• determining the authenticity of the decrypted first public key;
• and authenticating that the electronic control unit is an authentic device in the case that the first public key has been determined to be authentic.

A method for authenticating an electronic control unit comprising:

• generating, by a signature generation device, an electronic signature of a first public key,
• writing, by an information writing device, the first public key and a first secret key to be paired with the first public key in a first storage of the electronic control unit connected to a network inside a vehicle,
• printing, by a printing device, information in which the first public key attached with the electronic signature is made visible on the electronic control unit or an attachment of the electronic control unit,
• writing, by an information writing device, a second secret key, a second public key and a signature verification key for verifying the authenticity of the electronic signature attached to the first public key in a second storage of an on-vehicle authentication device,
• acquiring, by a visible information acquiring device, the printed information,
• acquiring, by the on-vehicle authentication device, the first public key attached with the electronic signature on the basis of the information acquired by the visible information acquiring device;
• verifying the authenticity of the electronic signature attached to the acquired first public key using the signature verification key stored in the second storage;
• encrypting the second public key stored in the second storage using the first public key attached with the electronic signature having been determined to be authentic by the verification;
• and transmitting the encrypted second public key to the electronic control unit via the network,
• receiving, by the electronic control unit, the encrypted second public key from the on-vehicle authentication device;
• decrypting the received second public key using the first secret key stored in the first storage;
• encrypting the first public key stored in the first storage using the decrypted second public key;
• and
• transmitting the encrypted first public key to the on-vehicle authentication device via the network, and
• receiving, by the on-vehicle authentication device, the encrypted first public key from the electronic control unit;
• decrypting the received first public key using the second secret key stored in the second storage;
• determining the authenticity of the decrypted first public key;
• and authenticating that the electronic control unit is an authentic device in the case that the first public key has been determined to be authentic.