Tachograph and Toll Unit Secure Data Bus Authentication

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Solution Overview

Problem

Current vehicle communication systems lack reliable and cost-effective methods for securing data transmission between tachographs and toll on-board units, particularly in ensuring data integrity and authenticity without requiring separate data connections, which is essential for trustworthy data exchange in vehicles.

Innovation Solution

The system employs a vehicle data bus interface for data communication between tachographs and toll on-board units, utilizing cryptographic test values and secure memory for key management, enabling secure data transmission and authentication through message authentication codes, thereby protecting against unauthorized manipulation and eliminating the need for separate data connections or redundant sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If cryptographic authentication is implemented using existing vehicle data bus, then data security is improved, but system complexity increases due to key management requirements

Engineering Contradiction:
Improvedata securityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

A gateway unit is introduced as an intermediary component that manages cryptographic keys and authentication processes. The gateway stores master keys, generates session keys, and coordinates authentication between tachograph and toll on-board unit, thereby centralizing security management and reducing the cryptographic burden on individual devices.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

Cryptographic keys are pre-distributed to the gateway unit before actual data transmission occurs. The gateway pre-generates session keys from master keys and prepares authentication credentials in advance, enabling rapid authentication without real-time key generation delays.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If separate data connections are used for secure communication, then data integrity is improved, but device complexity and cost increase

Engineering Contradiction:
Improvedata integrityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines secure cryptographic authentication with existing vehicle data bus communication infrastructure. Instead of creating separate physical communication channels, the security layer is integrated into the existing CAN bus or similar vehicle networks, merging authentication functions with standard data transmission protocols.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The vehicle data bus is designed to serve multiple functions simultaneously: standard vehicle control communication and secure tachograph-toll unit authentication. The same physical medium carries both regular vehicle data and cryptographic authentication messages, eliminating the need for dedicated secure channels.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Measurement precision

If redundant sensors are deployed for verification, then measurement precision is improved, but manufacturing cost increases

Engineering Contradiction:
Improvedata verification accuracyVSAvoidmanufacturing cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

Physical redundant sensors are replaced with cryptographic verification mechanisms. Instead of using multiple physical sensors to cross-verify measurements, the system uses mathematical authentication protocols where the tachograph and toll on-board unit verify data authenticity through cryptographic signatures and message authentication codes.

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

Solution Approach 2:

The patent uses cryptographic copies (digital signatures and hash values) of original data to verify authenticity. Rather than creating physical copies through redundant sensors, the system generates mathematical representations that can be verified without duplicating the physical measurement infrastructure.

Inventive Principle:
Principle #26Copying

Data Source

PatentEP2195790B1System comprising a tachograph and a toll onboard unit as data communication partners
Publication Date: 2017.05.03 CONTINENTAL AUTOMOTIVE GMBH
  • EP2195790B1 patent drawingFigure 1~2C
  • EP2195790B1 patent drawingFigure 3~5
  • EP2195790B1 patent drawingFigure 6

AI summary

A system comprises a tachograph (DTCO) and a toll onboard unit (OBU) as communication partners, which each comprise a data interface (DS) for a data communication via a vehicle data bus (FDB) to which the communication partners may be coupled. The tachograph (DTCO) and/or the toll onboard unit (OBU) are implemented as a transmitter of data to ascertain a cryptographic check value as a function of user data, which are to be transmitted to the communication partner, and to transmit the cryptographic check value in addition to the user data to the communication partner. The toll onboard unit (OBU) or the tachograph (DTCO), respectively, as a receiver of data, is implemented to receive user data and the cryptographic check value associated with the user data from the communication partner and to check the received user data for corruption as a function of the received cryptographic check value.