Automotive Communication Node Authentication With Sequential Scrambled Codes

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Solution Overview

Problem

The evolution of automotive electrical and electronic (E/E) architectures towards zone-oriented networks increases the risk of malicious attacks on vehicle communication networks due to the concentration of control logic in zonal gateways, necessitating improved security mechanisms for network-driven smart nodes.

Innovation Solution

Implementing a security layer within smart nodes using a cryptographic key-based protocol, where a communication commander device and responder device exchange scrambled codes to authenticate each other, granting access only when codes match, thereby securing communication and preventing unauthorized access.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If control logic is concentrated in zonal gateways to reduce complexity and cost, then device complexity and total cost of ownership are reduced, but security risk increases due to potential malicious attacks on the communication network

Engineering Contradiction:
ImproveE/E architecture complexityVSAvoidsecurity risk
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent implements preliminary security actions by establishing authentication protocols before allowing communication between smart nodes and zonal gateways. Security codes are generated and verified in advance, preventing unauthorized access before malicious attacks can occur. This resolves the contradiction by adding security measures that do not increase architectural complexity but protect against harmful factors.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces cryptographic authentication mechanisms as intermediaries between smart nodes and zonal gateways. These authentication protocols act as mediators that verify communication legitimacy without requiring complex security infrastructure. This resolves the contradiction by adding a security layer that maintains architectural simplicity while protecting against network attacks.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If authentication protocols are implemented in smart nodes to prevent unauthorized access, then security is improved, but device complexity and power consumption increase

Engineering Contradiction:
ImprovesecurityVSAvoidsmart node complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the complex authentication logic from the smart nodes and places it in the zonal gateway. The smart nodes only need to generate and transmit simple security codes, while the heavy computational burden of verification is performed by the gateway. This resolves the contradiction by improving security through authentication while keeping smart node complexity low.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses lightweight cryptographic codes that are generated and discarded after single-use authentication. These temporary security tokens provide strong authentication without requiring complex long-term security infrastructure in the smart nodes. This resolves the contradiction by providing robust security through simple, disposable authentication mechanisms.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Reliability

If cryptographic authentication is implemented in smart nodes, then unauthorized access is prevented, but power consumption and area usage increase

Engineering Contradiction:
Improveaccess controlVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent extracts power-intensive cryptographic operations from the smart nodes and centralizes them in the zonal gateway. Smart nodes only perform lightweight code generation and transmission, while the gateway handles complex verification. This resolves the contradiction by preventing unauthorized access through cryptography while minimizing power consumption in battery-constrained smart nodes.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent implements partial authentication where smart nodes perform only the minimal necessary security operations (code generation and transmission), while the gateway performs the complete verification process. This resolves the contradiction by providing sufficient access control security without requiring full cryptographic capability in every smart node, thus reducing power consumption.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP4641973A1Method of operating electronic devices in an automotive communication network, and corresponding devices
Publication Date: 2025.10.29 STMICROELECTRONICS INT NV
  • EP4641973A1 patent drawingFigure 1~2
  • EP4641973A1 patent drawingFigure 3
  • EP4641973A1 patent drawingFigure 4

AI summary

A method of operating an automotive communication network is disclosed. A communication commander device (32) sends (701) a request message (REQ). A communication responder device (30) receives (702) the request message, generates (703) a first code (CODE(i)) of a sequence of codes, scrambles (703) the first code with a first cryptographic key fetched (703) from a non-volatile memory (566) to generate a corresponding first scrambled code (SCRAMB_CODE(i)), sends (704) a response message including the first scrambled code, and generates (705) a subsequent code (CODE (i+1)) of the sequence of codes as a function of the first code. The commander receives (706) the response message, descrambles (707) the first scrambled code with a second cryptographic key fetched (707) from a non-volatile memory (422) to generate a corresponding first unscrambled code (UNSCRAMB_CODE(i)), generates (708) a subsequent unscrambled code (UNSCRAMB_CODE(i+1)) as a function of the first unscrambled code, and sends (709) a further message including the subsequent unscrambled code. The first and second cryptographic keys are the same. The sequential code generators of the commander and the responder implement the same code generation rules. The responder receives (710) the further message and compares (711) the subsequent unscrambled code to the subsequent code. If the subsequent unscrambled code and the subsequent code are equal, the commander gets access (712) to the functional registers of the responder. Otherwise, the commander is denied access (713) to the functional registers of the responder.