Updating A Secret Key for MAC Implemented on CAN Using Broadcast Encryption Scheme

In recent years, CAN is spread widely as the in-vehicle network. However, CAN protocol does not guarantee the security for traffics against falsification and spoofing. Therefore, the MAC is required for CAN so as to communicate exactly. MAC is the countermeasure for falsification and spoofing using the secret key. The problem is a method of delivering the secret key securely. This paper proposes a method to update the secret key using broadcast encryption over a non-supersingular elliptic curve. The method is implemented on Raspberry Pi and experimentally find out to be able to update the secret key efficiently.