A hardware-based security scheme for in-vehicle CAN

The Controller Area Network (CAN) is the most popular protocol for electronic control units (ECUs) in vehicles which require high security. Recent usages of CAN have raised security issues because of wireless connection demanded by users. This paper presents a hardware-based scheme for increasing security in CAN. The proposed scheme is based on a previous scheme that applied the Advanced Encryption Standard (AES) but suffer some delay time during a key update process. In our scheme, hardware-based key generator and AES are embedded in all nodes of which one is assigned as the head and another is as the tail. Hence, each node will generate exactly same key every time a synchronous pulse from the head node is received. Moreover, a procedure for measuring time delay compare between tail node and each node is proposed. Each node stores and uses this time delay to decide when to make the update so that all nodes making the update at the same clock. As a result, the proposed key updating can be executed in a few clocks dependent on only the delay between a node and the tail node. This delay measuring process is done only during the system installation. Sets of simulations and experiments were carried out to confirm that the proposed scheme can synchronize the key during the updating process correctly.