Certificate Expiration Verification Using Stored Time Logs

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Solution Overview

Problem

Existing systems fail to verify the expiration of public key certifications when date and time information cannot be received due to communication breakdowns, particularly in mobile objects where the communication environment changes.

Innovation Solution

A certification verification device and method that utilize stored date and time information and logs to verify certification expiration, even when real-time information is unavailable, by using second date and time information associated with stored logs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If real-time date and time information is used to verify certification expiration, then verification accuracy is improved, but system reliability deteriorates when communication breakdown occurs

Engineering Contradiction:

Improveverification accuracyVSAvoidsystem reliability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The system performs preliminary actions by storing multiple date and time information sources (first from GPS receiver, second from log storage) before communication breakdown occurs. When real-time information becomes unavailable, the pre-stored second date and time information from logs enables continued verification operations without system failure.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If real-time date and time information is continuously received to ensure accurate verification, then verification reliability is improved, but network traffic increases

Engineering Contradiction:

Improveverification reliabilityVSAvoidnetwork traffic

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The system applies partial action by using stored second date and time information from logs instead of continuously receiving real-time information. This partial use of pre-stored data maintains sufficient verification reliability while significantly reducing network traffic and energy consumption associated with continuous real-time information reception.

Inventive Principle:

Principle #16Partial or excessive action

3Loss of time

If the system continuously monitors date and time information to verify certification expiration, then verification timeliness is improved, but device complexity increases

Engineering Contradiction:

Improveverification timelinessVSAvoiddevice complexity

Core Design Contradiction:

Loss of timeVSDevice complexity

Solution Approach 1:

The system extracts and stores date and time information separately in log storage at different time points, creating independent data sources. This extraction approach simplifies the monitoring mechanism by using pre-stored information for verification comparisons, reducing the complexity of continuous real-time monitoring while maintaining verification timeliness.

Inventive Principle:

Principle #2Taking out (Extraction)

Data Source

PatentUS12537812B2Certification verification device, certification verification method, and non-transitory computer-readable storage medium storing certification verification program

Publication Date: 2026.01.27 DENSO CORP

AI summary

By a certification verification device, a certification verification method, or a non-transitory computer-readable storage medium storing a certification verification program, a certification is received from an authentication request device and first date and time information that is time and date information from a date and time distribution device, the first date and time information is stored, a generated or received log is stored, it is verified whether the certification has expired using the first date and time information, and use second date and time information associated with the stored log is used to verify whether the certification has expired.