CAN Transceiver Frame Authorization for Secure Bus Control

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Solution Overview

Problem

Existing CAN transceivers do not adequately address network security concerns, allowing malicious devices to hijack bus control and potentially cause damage by transmitting unauthorized frames that bypass standard error detection mechanisms.

Innovation Solution

The CAN transceiver incorporates a control unit that analyzes frames for authorization by checking the acknowledgement delimiter bit (AD bit) and end-of-frame field (EOF field) before controlling the control interface, ensuring only authorized frames are used to prevent unauthorized access and potential damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a typical transceiver provides ISO 11898 standard compliant communication without scrutinizing data content, then communication compatibility is improved, but network security deteriorates

Engineering Contradiction:
Improvecommunication compatibilityVSAvoidnetwork security
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The transceiver performs preliminary scrutiny of incoming frames by checking the AD bit and EOF field before processing or forwarding the data content. This preliminary validation action prevents unauthorized frames from entering the system, thereby maintaining network security while still supporting standard CAN communication protocols.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the transceiver scrutinizes all data content for security, then network security is improved, but processing time increases

Engineering Contradiction:
Improvenetwork securityVSAvoidframe processing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The transceiver performs partial scrutiny by checking only specific critical fields (AD bit and EOF field) rather than analyzing the entire data content of each frame. This partial validation approach provides sufficient security protection against unauthorized frames while minimizing the time overhead associated with frame processing.

Inventive Principle:
Principle #16Partial or excessive action

3Reliability

If the transceiver checks AD bit and EOF field for every frame, then security against unauthorized frames is improved, but device complexity increases

Engineering Contradiction:
Improvesecurity against unauthorized framesVSAvoidframe validation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The transceiver applies localized validation by checking specific critical fields (AD bit and EOF field) rather than implementing comprehensive analysis of the entire frame structure. This targeted approach to security validation provides effective protection against unauthorized frames while keeping the validation logic simple and the device complexity low.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4304135B1Controller area network (CAN) transceiver, can node, can system and method for the can transceiver
Publication Date: 2025.12.03 NXP BV
  • EP4304135B1 patent drawingFigure 1
  • EP4304135B1 patent drawingFigure 2
  • EP4304135B1 patent drawingFigure 3

AI summary

The present invention relates to Controller Area Network, CAN, transceiver, wherein the control unit of the CAN transceiver is configured to classify a potentially relevant frame as either an authorized frame or an unauthorized frame based on an acknowledge delimiter bit and based on an bit of the end of frame field, such that the control unit is able to control a supplement control interface of the CAN transceiver based on a data field of the authorized frame if the data field of the AT frame represents control instructions for controlling the control interface. The present invention also relates to a CAN node including the CAN transceiver, a CAN system and a method for the CAN transceiver.