Terminal Access Certificate Selection by Root Issuer Matching

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Solution Overview

Problem

Existing systems face inefficiencies in authorizing mobile computers to access terminals, such as charging stations, without sufficient verification of certificate chains, leading to unauthorized access or the need for additional authorization information.

Innovation Solution

A mobile computer selects an access certificate chain based on an issuer identifier associated with a root certificate authority, ensuring authorization by matching the issuer identifier with a stored root certificate, thereby enhancing the efficiency of access authorization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a mobile computer stores multiple access certificate chains for different terminal computers, then the mobile computer can access multiple terminals, but the complexity of selecting the correct certificate chain increases

Engineering Contradiction:

Improveaccess capability to multiple terminalsVSAvoidcertificate chain selection complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The terminal computer provides its identity information (issuer identifier) to the mobile computer before the actual access operation. The mobile computer uses this pre-provided information to select the appropriate certificate chain from its stored multiple chains, avoiding the need to try multiple chains during the access process itself.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The terminal computer gives feedback to the mobile computer by providing its issuer identifier, which guides the mobile computer in selecting the correct certificate chain. This feedback mechanism enables the mobile computer to adapt its certificate selection based on the specific terminal it is attempting to access.

Inventive Principle:

Principle #23Feedback

2Reliability

If the mobile computer tries multiple access certificate chains to find a match, then it can ensure access authorization, but the time required for authentication increases

Engineering Contradiction:

Improveauthorization verification reliabilityVSAvoidauthentication time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The mobile computer performs preliminary matching of the terminal's issuer identifier with the issuer identifiers stored in its certificate chains before attempting access. This pre-matching process ensures that only the correct certificate chain is used during the actual authentication, eliminating the need to try multiple chains and reducing authentication time while maintaining reliability.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces a trial-and-error mechanical approach (trying multiple certificate chains sequentially) with an information-based selection approach (matching issuer identifiers). This substitution uses data comparison rather than brute-force testing, significantly reducing the time required while ensuring correct authorization verification.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If the system requires additional authorization information from remote computers, then access security is improved, but the complexity of the access process increases

Engineering Contradiction:

Improveaccess securityVSAvoidaccess process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the essential authorization verification function to a remote authorization server. Instead of implementing complex local verification logic in the mobile computer, the system outsources the authorization decision-making to a dedicated remote server that receives the selected certificate chain and returns an authorization result, simplifying the local device while maintaining security.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The remote authorization server acts as an intermediary between the mobile computer and the terminal computer. It receives the selected certificate chain from the mobile computer, performs the authorization check, and returns the result to the terminal, mediating the access control process and reducing the complexity burden on the mobile device.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS20250350479A1Access to a terminal

Publication Date: 2025.11.13 FORD GLOBAL TECH LLC

AI summary

Upon requesting access to a terminal, a mobile computer receives a communication certificate chain from a terminal computer included in the terminal. The mobile computer establishes a communication session with the terminal computer based on an issuer identifier associated with a root certificate in the communication certificate chain matching a stored issuer identifier. Upon establishing the communication session, the mobile computer determines, for each of a plurality of access certificate chains, a respective issuer identifier associated with a respective root certificate in the corresponding access certificate chain. Upon determining that the respective issuer identifier in one access certificate chain matches the stored issuer identifier, the mobile computer selects the one access certificate chain. The mobile computer transmits the selected access certificate chain to the terminal computer.