Limited-Use Electronic Certificates for PKI Anomaly Handling

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Solution Overview

Problem

In machine-to-machine based certificate enrollment, renewal, or rekeying processes, when a certificate request is rejected by a Public Key Infrastructure (PKI), the end entity loses immediate access to associated services, necessitating a solution that allows continued, albeit limited, access to facilitate corrective actions.

Innovation Solution

A PKI device detects anomalies in certificate requests and issues a limited-use electronic certificate with attributes such as a shortened validity period or lower assurance level, allowing the end entity to maintain access while addressing the anomaly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a certificate request is rejected by the PKI due to detected anomalies, then security is improved, but service access is lost

Engineering Contradiction:
ImprovesecurityVSAvoidservice access
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent segments the certificate issuance process into two distinct pathways: full-access certificates for normal requests and limited-use certificates for anomalous requests. This segmentation allows the system to maintain strict security validation while providing differentiated access levels, resolving the contradiction between security enforcement and service continuity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the access parameters by issuing certificates with modified attributes (limited validity period, restricted services, reduced assurance level) when anomalies are detected. This parameter modification enables continued service access under controlled conditions, balancing security requirements with operational needs.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If a full certificate is issued without anomaly detection, then service access is maintained, but security risk increases

Engineering Contradiction:
Improveservice accessVSAvoidsecurity risk
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent implements a feedback mechanism where the PKI continuously monitors certificate requests for anomalies and adjusts the certificate issuance decision accordingly. This feedback loop enables dynamic security adjustment, maintaining service access while responding to security threats in real-time.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent applies partial action by issuing limited-use certificates that provide sufficient access for legitimate operations while imposing restrictions that prevent excessive or harmful usage. This partial certification approach mitigates security risks while maintaining necessary service functionality.

Inventive Principle:
Principle #16Partial or excessive action

3Productivity

If a limited-use certificate is issued for anomalous requests, then operational efficiency is improved, but certificate assurance level is reduced

Engineering Contradiction:
Improveoperational efficiencyVSAvoidcertificate assurance level
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent introduces dynamic certificate issuance where the assurance level and access permissions are adjusted based on the anomaly detection results. This dynamic approach allows the system to optimize operational efficiency for each request while maintaining appropriate security assurance levels through conditional restrictions.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4494309B1Device and method for issuing a limited-use electronic certificate
Publication Date: 2025.11.05 MOTOROLA SOLUTIONS INC
  • EP4494309B1 patent drawingFigure 1
  • EP4494309B1 patent drawingFigure 2
  • EP4494309B1 patent drawingFigure 3

AI summary

A process of issuing a limited-use electronic certificate. In operation, a public key infrastructure (PKI) device receives a request for an electronic certificate from an end entity. The PKI device detects an anomaly with respect to the request received from the end entity. The PKI device generates, based on the detected anomaly, a limited-use electronic certificate. The PKI then issues the limited-use electronic certificate to the end entity. When the end entity determines that the issued certificate is a limited-use certificate with limited-use attributes such as a shortened validity period or lowered assurance level, the end entity provides a visual and/or audio prompt indicating the issuance of the limited-use certificate and further including one or more corrective actions to be performed to eliminate the anomaly prior to sending a new request for an electronic certificate to the PKI device.