Vehicle Device Authentication via HMAC and Random Challenge

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Solution Overview

Problem

In vehicles, the lack of authentication mechanisms for devices connected to a public communication network makes the system vulnerable to tampering and security breaches, as data exchanged over the communication bus is unprotected, allowing for interception and corruption of messages.

Innovation Solution

An authentication system that generates a random number, uses a HMAC algorithm to verify the authenticity of devices, and inhibits operations if authentication fails after a preset number of attempts, ensuring only authenticated devices can communicate and operate within the system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If authentication mechanisms are implemented for devices connected to the public communication network, then security and data integrity are improved, but device complexity and operational overhead increase

Engineering Contradiction:
ImprovesecurityVSAvoidcomplexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The authentication key is pre-loaded into the device during manufacturing or initialization. This preliminary action ensures that the device has the necessary security credentials before it connects to the communication network, eliminating the need for complex real-time key distribution mechanisms and reducing operational complexity while maintaining security

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces an authentication intermediary mechanism where the master controller verifies device authenticity through HMAC comparison. This intermediary authentication layer sits between the device and the communication network, providing security without requiring complex modifications to the underlying communication infrastructure

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If authentication verification is performed for each device connection, then unauthorized access is prevented, but communication speed and system responsiveness decrease

Engineering Contradiction:
ImprovesecurityVSAvoidcommunication speed
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The authentication key is pre-configured in the device before connection, allowing for rapid verification. The device already possesses the necessary credentials, eliminating the need for time-consuming key exchange protocols during connection establishment

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The authentication process uses a simplified HMAC verification approach that checks only the essential security parameters rather than performing comprehensive security checks. This partial verification approach provides sufficient security while minimizing the time required for authentication

Inventive Principle:
Principle #16Partial or excessive action

3Ease of operation

If multiple authentication attempts are allowed, then legitimate devices can overcome temporary errors, but the vulnerability to brute force attacks increases

Engineering Contradiction:
Improvetolerance to errorsVSAvoidvulnerability to attacks
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The system implements feedback through the counter mechanism that tracks authentication attempts. When the counter reaches the threshold, the system provides feedback by blocking further authentication attempts and inhibiting vehicle operations. This feedback loop prevents brute force attacks while still allowing legitimate devices reasonable opportunities to correct temporary errors

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically changes the parameter of authentication attempt tolerance based on the counter value. Initially, multiple attempts are permitted, but as the counter approaches the threshold, the system becomes increasingly restrictive, ultimately blocking access when the threshold is reached. This parameter change strategy balances error tolerance with attack prevention

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4107038B1Authenticating devices over a public communication network
Publication Date: 2024.04.17 BAE SYSTEMS CONTROLS INC
  • EP4107038B1 patent drawingFigure 1
  • EP4107038B1 patent drawingFigure 2
  • EP4107038B1 patent drawingFigure 3

AI summary

Apparatus and method for authentication components of a public network are disclosed. A master compares an actual HMAC with an expected HMAC, determines that component fails authentication when the actual HMAC does not match the expected HMAC and causes at least one operation to be inhibited when component fails authentication for a preset number of times while the component is connected to the public network. The actual HMAC is determined by the component. The expected HMAC and actual HMAC are independently determined using the same process and using a key. The same key is stored, in advance, in both the master and the component and not transmitted. The master generates a random number and sends the same to the component. The expected HMAC and actual HMAC are determined using the random number input into a one-way hash function.