Vehicle-Roadside Certificate Verification with Time-Location Validity Lists

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Solution Overview

Problem

The public key encryption system used in vehicle-to-vehicle communication does not effectively shorten signature verification time due to the need for frequent certificate verification, which is time-consuming and can lead to increased CRL sizes and server inquiries.

Innovation Solution

Implement a communication system where a certificate authority generates and distributes whitelists and blacklists based on vehicle position and time, allowing roadside devices and vehicle-mounted terminals to verify certificates using these lists, reducing the need for real-time inquiries and shortening verification time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If certificate verification is performed using the public key encryption system in vehicle-to-vehicle communication, then message validity is ensured, but verification time increases and communication efficiency decreases

Engineering Contradiction:
Improvemessage validityVSAvoidverification time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-distributing certificates and CRLs to roadside devices before vehicles need to verify them. The system proactively manages certificate validity periods and distributes updated CRLs in advance, allowing vehicles to perform verification without time-consuming real-time inquiries. This resolves the contradiction by preparing verification materials beforehand, ensuring message validity while reducing verification time.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces roadside devices as intermediaries between the certificate authority and vehicles. These roadside devices pre-obtain and store certificates and CRLs, then provide them to vehicles during communication. This intermediary approach eliminates the need for vehicles to directly inquire the certificate authority in real-time, thus ensuring message validity through proper certificate verification while significantly reducing verification time.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If real-time certificate verification is performed, then security is maintained, but the number of server inquiries increases and system load increases

Engineering Contradiction:
ImprovesecurityVSAvoidserver inquiry frequency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent extracts the certificate verification function from the central certificate authority and distributes it to roadside devices. These roadside devices maintain local copies of certificates and CRLs, enabling them to perform verification independently without requiring real-time server inquiries. This extraction maintains security through proper verification while dramatically reducing the number of inquiries to the certificate authority server.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system performs preliminary distribution of certificates and CRLs to roadside devices before they are needed for verification. By proactively managing certificate validity periods and distributing updated CRLs in advance, the system eliminates the need for frequent real-time inquiries to the server, thus maintaining security while reducing server load and inquiry frequency.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If CRL distribution is expanded to cover wide areas, then certificate revocation coverage is improved, but CRL size increases and distribution complexity increases

Engineering Contradiction:
Improvecertificate revocation coverageVSAvoidCRL distribution complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the CRL distribution system by assigning different CRLs to different geographic regions covered by different roadside devices. Instead of distributing a single large CRL covering the entire network, each roadside device maintains CRLs relevant to its local region. This segmentation improves certificate revocation coverage across wide areas while reducing the size and distribution complexity of individual CRLs, as each contains only the revocation information relevant to its region.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2579498B1Communication system, vehicle-mounted terminal, roadside device
Publication Date: 2025.08.20 RENESAS ELECTRONICS CORP
  • EP2579498B1 patent drawingFigure 1
  • EP2579498B1 patent drawingFigure 2
  • EP2579498B1 patent drawingFigure 3

AI summary

There is a need to reduce the certificate verification time in a communication system. A communication system (10) includes a certificate authority (100) for performing authentication, a roadside device (110), a vehicle-mounted terminal (120), a first server (130), and a second server (140). The vehicle-mounted terminal transmits its own position information to the first server. The certificate authority acquires information about a vehicle-mounted terminal highly likely to appear according to place and time from the first server. The certificate authority allows the second server to verify validity of a certificate for a vehicle-mounted terminal acquired from the first server. The certificate authority generates a first list of vehicle-mounted terminals having valid certificates and a second list of vehicle-mounted terminals having invalid certificates according to place and time based on a verification result. The certificate authority transmits the first list and the second list to the roadside device and the vehicle-mounted terminal. The roadside device and the vehicle-mounted terminal verify a certificate using the received first and second lists. Thus, the certificate verification time is reduced.