Patent ID: 9725073
Date: 2017-08-08
CPC Classifications: B60R,H04L

Claim:
1. An anti-fraud method for use in an in-vehicle network system including a plurality of electronic control units that exchange data frames, each having added thereto a message authentication code (MAC), via at least one bus in accordance with a Controller Area Network (CAN) protocol, the anti-fraud method comprising: receiving a data frame transmitted on the bus; generating a first message authentication code by using a MAC key and a value of a counter that counts the number of times a data frame having added thereto a message authentication code is transmitted; verifying that the received data frame has added thereto the generated first message authentication code; generating, in a case where the verification has failed, a second message authentication code by using a MAC key before update of the MAC key; re-verifying, in a case where the verification has failed, that the received data frame has added thereto the generated second message authentication code; transmitting, in a case where the re-verification has succeeded, via the bus a key-update frame indicating a request for updating the MAC key; and updating the MAC key in response to the transmission of the key-update frame.