System and method for a vehicle network

Patent metadata

Field	Value
Publication number	US-11792007-B2
Application number	US-202117203775-A
Country	US
Kind code	B2
Filing date	Mar 17, 2021
Priority date	Mar 17, 2021
Publication date	Oct 17, 2023
Grant date	Oct 17, 2023

Abstract

An onboard communication network of a vehicle is monitored to detect a plurality of available messages that include respective cipher-based message authentication codes (CMAC) and that were identified as eligible messages based on having an information entropy greater than a specified threshold. A first message is selected from the plurality of available messages. The CMAC of the selected message is input into a random number generator that outputs a random number seeded by the CMAC of the selected message. Then the random number is provided.

First claim

What is claimed is:

1. A system, comprising a computer including a processor and a memory, the memory storing instructions executable by the processor to:
monitor an onboard communication network of a vehicle to detect a plurality of available messages that include respective cipher-based message authentication codes (CMAC) and that were identified as eligible messages based on having a number of bits in the respective message that cannot be determined before the message is sent greater than a specified threshold;
select a first message from the plurality of available messages;
upon determining a length of the CMAC of the selected message is less than a length of a seed value specified by a random number generator that outputs a random number, select a second message from the plurality of available messages;
generate an updated CMAC by combining the CMAC of the second message and the CMAC of the first message;
input the updated CMAC into the random number generator based on determining a length of the updated CMAC is equal to the length of the seed value; and
then output the random number.

2. The system of claim 1 , wherein the instructions further include instructions to maintain a list of the eligible messages on the vehicle communication network, and to incrementally select the first message from the list.

3. The system of claim 2 , wherein the instructions further include instructions to remove messages from the list after a predetermined time.

4. The system of claim 1 , wherein the instructions further include instructions to maintain a list of the eligible messages on the vehicle communication network, and to select the first message from the list based on a previous random number.

5. The system of claim 4 , wherein the instructions further include instructions to remove messages from the list after a predetermined time.

6. The system of claim 1 , wherein the random number is input to an application for a security function.

7. The system of claim 1 , wherein the instructions further include instructions to select the first message based on receiving a request for a random number.

8. The system of claim 7 , wherein the instructions further include instructions to select, as the first message, a most recent available message detected on the onboard communication network after receiving the request.

9. The system of claim 8 , wherein the instructions further include instructions to select, as the first message, a next available message detected on the onboard communication network after receiving the request.

10. A method, comprising:
monitoring an onboard communication network of a vehicle to detect a plurality of available messages that include respective cipher-based message authentication codes (CMAC) and that were identified as eligible messages based on having a number of bits in the respective message that cannot be determined before the message is sent greater than a specified threshold;
selecting a first message from the plurality of available messages;
inputting the CMAC of the selected message into a random number generator that outputs a random number seeded by the CMAC of the selected message;
upon determining a length of the CMAC of the selected message is less than a length of a seed value specified by a random number generator that outputs a random number, selecting a second message from the plurality of available messages;
generating an updated CMAC by combining the CMAC of the second message and the CMAC of the first message;
inputting the updated CMAC into the random number generator based on determining a length of the updated CMAC is equal to the length of the seed value; and
then outputting the random number.

11. The method of claim 10 , further comprising maintaining a list of the eligible messages on the vehicle communication network, and incrementally selecting the first message from the list.

12. The method of claim 11 , further comprising removing messages from the list after a predetermined time.

13. The method of claim 10 , further comprising maintaining a list of the eligible messages on the vehicle communication network, and selecting the eligible message from the list based on a previous random number.

14. The method of claim 13 , further comprising removing messages from the list after a predetermined time.

15. The method of claim 11 , wherein the random number is input to an application for a security function.

16. The method of claim 10 , further comprising selecting the message based on receiving a request for a random number.

17. The method of claim 16 , further comprising selecting, as the first message, a most recent available message detected on the onboard communication network after receiving the request.

18. The method of claim 16 , further comprising selecting, as the first message, a next available message detected on the onboard communication network after receiving the request.

Assignees

• Ford Global Tech Llc

Inventors

• Kajuluri Venkata Kishore
• Ye Xin
• Smith Bradley Warren
• Nelson Jacob David

Classifications

• H04L9/32 Primary

  including means for verifying the identity or authority of a user of the system {or for message authentication, e.g. authorization, entity authentication, data integrity or data verification, non-repudiation, key authentication or verification of credentials} · CPC title

• G06F7/588 Primary

  Random number generators, i.e. based on natural stochastic processes · CPC title

• H04W4/40 Primary

  for vehicles, e.g. vehicle-to-pedestrians [V2P] · CPC title

• H04W4/38

  for collecting sensor information · CPC title

• H04L9/3226

  using a predetermined code, e.g. password, passphrase or PIN (network architectures or network communication protocols for supporting authentication of entities using passwords in a packet data network H04L63/083) · CPC title