Authentication system for electronic control unit on a bus

An authentication method comprising:

• applying a physical layer authentication signal to a message to be sent by a transmitter on a bus;
• the transmitter applying a unique modulated analog signal encoding an identifier (ID) of the transmitter to the physical layer authentication signal;
• decoding the physical layer authentication signal on the message to be received by a receiver on the bus, the decoding the physical layer includes demodulating the unique modulated analog signal to determine the ID of the transmitter sending the message and identifying a message type of the message;
• and
• looking up the ID of the transmitter on a list of IDs corresponding to transmitters approved to send the message to determine whether the ID decoded from the physical layer authentication signal matches an ID on the list and compare a message type of the message to message types authorized to be sent by the transmitter sending the message;
• and
• wherein:
• if the ID matches an ID on the list and the message type is authorized to be sent by the transmitter, then the message on the bus is authorized;
• and
• if 1) the ID matches no ID on the list or 2) the ID matches an ID on the list and the transmitter is not authorized to send the message type of the message, then the message on the bus is unauthorized and the further comprises blocking a processing of the message by the receiver by asserting a signal on the bus that causes a cyclic redundancy code (CRC) associated with the message to be corrupted.

A mechanism for authenticating transmissions, comprising:

• a transmitting entity;
• an authenticating receiving entity;
• and
• a bus connected to the transmitting entity and the authenticating receiving entity;
• wherein:
• a physical layer signal is applied by the transmitting entity to a message on the bus to authenticate the transmitting entity;
• the physical layer signal incorporates an identifier (ID) of the transmitting entity;
• the transmitting entity applies a unique modulated analog signal encoding the ID of the transmitting entity to the physical layer signal;
• the authenticating receiving entity receives the message and decodes the physical layer signal on the message;
• the decoding of the physical layer signal on the message includes demodulating the unique modulated analog signal to determine the ID of the transmitting entity sending the message and identifying a message type of the message;
• the authenticating receiving entity looks up the ID of the transmitting entity on a list of IDs corresponding to transmitting entities approved to send the message to determine whether the ID of the transmitting entity sending the message matches an ID on the list and compare a message type of the message to message types authorized to be sent by the transmitter sending the message;
• if the ID of the transmitting entity matches an ID on the list and the message type is authorized to be sent by the transmitter, then the transmitting entity is authenticated and authorized to send the message;
• and
• if 1) the ID of the transmitting entity does not match an ID on the list or 2) the ID of the transmitting entity matches an ID on the list and the transmitter is not authorized to send the message type of the message, then the transmitting entity is not authenticated and the authenticating receiving entity blocks a processing of the message by one or more additional receiving entities connected to the bus by asserting a signal on the bus that causes a cyclic redundancy code (CRC) associated with the message to be corrupted.