Authentication system for electronic control unit on a bus

Patent metadata

Field	Value
Publication number	US-11057213-B2
Application number	US-201715784044-A
Country	US
Kind code	B2
Filing date	Oct 13, 2017
Priority date	Oct 13, 2017
Publication date	Jul 6, 2021
Grant date	Jul 6, 2021

Abstract

An authentication system having a communications bus, a transmitter connected to the bus, and a receiver connected to the bus. A physical layer signal may be applied by the transmitter to a message on the bus for authenticating the transmitter. The physical layer signal may incorporate an identifier (ID) of the transmitter. The receiver may receive the message and decode the physical layer signal on the message. Decoding the physical layer signal on the message may reveal the ID of the transmitter sending the message. The receiver may look up the ID on a list of IDs corresponding to transmitters approved to send the message, to determine whether the ID of the transmitter sending the message matches an ID on the list. Only if the ID of the transmitter matches an ID on the list, then the transmitter may be authenticated and authorized to send the message.

First claim

What is claimed is:

1. An authentication system comprising:
a bus;
a plurality of transmitters connected to the bus;
an authenticating receiver connected to the bus; and
one or more additional receivers connected to the bus; and
wherein:
physical layer signals are applied by the transmitters to messages on the bus for authenticating a transmitter of the plurality of transmitters that sent a message;
the physical layer signal incorporates an identifier (ID) of the transmitter that sent the message;
each of the transmitters applies a unique modulated analog signal associated with the ID of the transmitter to the physical layer signal to incorporate and encode the ID of the transmitter in the physical layer;
the authenticating receiver 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 transmitter sending the message and identifying a message type of the message;
the authenticating receiver looks up the ID of the transmitter on a list of IDs corresponding to transmitters approved to send the message to determine whether the ID of the transmitter 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; and
if the ID of the transmitter matches an ID on the list and the message type is authorized to be sent by the transmitter, then the transmitter is authenticated and authorized to send the message; and
if 1) the ID of the transmitter matches no ID on the list or 2) the ID of the transmitter 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 may be unauthorized and the authenticating receiver blocks a processing of the message by the one or more additional receivers by asserting a signal on the bus that causes a code associated with the message to be corrupted.

2. The system of claim 1 , wherein:
if the transmitter is authenticated, the message sent by the transmitter that is received by the authenticating receiver is processed by the authenticating receiver; and
if the transmitter cannot be authenticated, then the message sent by the transmitter that is received by the authenticating receiver is blocked and not processed by the receiver.

3. The system of claim 2 , wherein the bus comprises one or more additional receivers that detect the blocking of the message by the authenticating receiver that checks the ID decoded from the physical layer signal on the message from the transmitter and determines that the ID of the transmitter does not match an ID on a list of IDs corresponding to transmitters approved to send the message, and in turn blocks the message.

4. The system of claim 1 , wherein a message having a physical layer signal, can be received by the authenticating receiver without interference to an ability of the authenticating receiver to receive and decode another message that is a normal signal digitized data message per a communications standard.

5. The system of claim 1 , wherein:
the bus is a controller area network (CAN);
the message is a CAN message;
the CAN message has a dominant portion and a recessive portion; and
the physical layer signal is applied to a recessive portion or a dominant and a recessive portion of the CAN message.

6. The system of claim 1 , wherein only one receiver on the bus needs to receive the message and decode the physical layer signal applied to the message.

7. The system of claim 1 , wherein if a transmitter is authorized to transmit a message, the authenticating receiver allows the message to be processed without interfering with the message.

8. The system of claim 1 , wherein:
the code is cyclic redundancy code (CRC); and
the one or more receivers detect corruption of the CRC associated with the message.

9. The system of claim 1 , wherein two or more receivers on the bus can receive and decode a physical layer signal on the message to obtain an ID of the transmitter of the message and determine whether the ID matches an ID on a list of IDs of transmitters authorized to send the message.

10. The system of claim 9 wherein:
if the any one of the two or more receivers determines that the transmitter is authorized to transmit the message, then the any one of the two or more receivers will allow the message to be processed by a local processor; and
if the any one of the two or more receivers determines that the transmitter was not authorized to transmit the message, then the any one of the two or more receivers will block a processing of the message by the local processor.

11. The system of claim 1 , wherein the bus comprises one of the following receiver and transmitter combinations of components:
one or more authenticating receivers, and one or more authenticating transmitters;
one or more authenticating receivers, one or more authenticating transmitters, and one or more non-authenticating receivers;
one or more authenticating receivers, one or more authenticating transmitters, and one or more non-authenticating transmitters;
one or more authenticating receivers, one or more authenticating transmitters, one or more non-authenticating receivers, and one or more non-authenticating transmitters;
only one authenticating receiver and only one authenticating transmitter;
only one authenticating receiver, only one authenticating transmitter, and one or more non-authenticating receivers;
only one authenticating receiver, only one authenticating transmitter, and one or more non-authenticating transmitters; or
only one authenticating receiver, only one authenticating transmitter, one or more non-authenticating receivers, and one or more non-authenticating transmitters.

12. The system of claim 11 , wherein a receiver and transmitter combination that has components that perform authenticating functions and non-authenticating functions interoperate in accordance with a security policy applied by one or more authenticating components.

13. 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.

14. The met

Assignees

• Garrett Transportation I Inc

Inventors

• Markham Thomas R
• Chernoguzov Alexander

Classifications

• H04L12/40104 Primary

  Security; Encryption; Content protection (cryptographic protocols H04L9/00; protocols for network security H04L63/00) · CPC title

• H04L63/0876

  based on the identity of the terminal or configuration, e.g. MAC address, hardware or software configuration or device fingerprint · CPC title

• H04L63/1416

  Event detection, e.g. attack signature detection · CPC title

• H04L63/20

  for managing network security; network security policies in general (filtering policies H04L63/0227) · CPC title

• H04L63/06

  for supporting key management in a packet data network (cryptographic mechanisms or cryptographic arrangements for key management H04L9/08) · CPC title