CAN ECU Communication Security Using In-Frame Authentication

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Solution Overview

Problem

Existing CAN protocol-based communication between ECUs in vehicles lacks robust security measures, making them vulnerable to attacks such as message injection and replay attacks, which can disrupt vehicle operations and compromise safety.

Innovation Solution

Implementing security features like sender authentication and message originality directly at the CAN protocol level using the excess data payload space, particularly in the CAN FD and CAN XL protocols, with hardware-based solutions to minimize CPU overhead and latency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If security features are implemented at higher levels in the communication stack, then security protection is provided, but delays occur due to increased processing time

Engineering Contradiction:
Improvesecurity protectionVSAvoiddelays
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent implements security features directly at the CAN protocol level rather than at higher communication stack layers. By embedding authentication and message integrity verification mechanisms in the protocol itself, security processing occurs concurrently with data transmission without requiring additional processing delays at higher levels.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediate security layer within the CAN protocol stack that mediates between the physical layer and higher application layers. This intermediary security mechanism handles authentication and integrity verification independently, preventing delays from propagating through the entire communication stack.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If security features are implemented in software, then flexibility is provided, but CPU overhead increases

Engineering Contradiction:
ImproveflexibilityVSAvoidCPU overhead
Core Design Contradiction:
Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent replaces software-based security implementations with hardware-based solutions. By implementing security features in dedicated hardware circuits within the CAN controller, the system eliminates the computational overhead of CPU-based security processing while maintaining flexibility through configurable hardware parameters.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent enables the CAN controller to perform security verification autonomously without requiring CPU intervention. The hardware-based security mechanism automatically handles authentication and message integrity checks, allowing the system to serve itself and eliminating the need for CPU resources to be consumed by security processing.

Inventive Principle:
Principle #25Self-service

3Reliability

If authentication and verification processes are added to CAN messages, then security is improved, but message transmission time increases

Engineering Contradiction:
ImprovesecurityVSAvoidmessage transmission time
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The patent merges security features directly into the CAN message structure by utilizing the existing message ID and data fields for authentication purposes. Rather than adding separate authentication messages or extending message length, the security information is embedded within the original message framework, maintaining transmission speed while improving security.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the interpretation and usage of existing CAN message parameters to serve dual purposes. The message ID and data fields are configured to contain both operational information and authentication data, allowing security verification to occur using the same transmission channel without increasing message size or transmission time.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4068722B1Enhanced secure onboard communication for can
Publication Date: 2026.02.25 RENESAS ELECTRONICS AMERICA INC
  • EP4068722B1 patent drawingFigure 1
  • EP4068722B1 patent drawingFigure 2A~2C
  • EP4068722B1 patent drawingFigure 3

AI summary

According to certain general aspects, the present embodiments relate generally to securing communication between ECUs. In some embodiments, this can be done by utilizing the excess space in the CAN protocols. According to certain other aspects, security features such as sender authentication and message originality can be implemented at the protocol level, reducing the delays associated with implementing security features at higher levels in the communication stack. Additionally, the complexity of the security configuration is minimized by implementing the security features in hardware.