Offline Private-Key Generation for Industrial Control Identity Management

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Solution Overview

Problem

Existing cryptographic systems face security concerns due to central storage of private keys, which can lead to widespread breaches if the central authority is compromised, and revocation of compromised keys is challenging due to timeliness, accuracy, verification, and scalability issues.

Innovation Solution

A system and method for cryptographic identity management in industrial control systems that generates private keys offline using identity-based encryption schemes and maintains a database of online identity statuses through identity revocation servers, allowing entities to request and verify their status for secure encryption and signature operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If private keys are stored centrally by a trusted authority, then key management is simplified, but security is compromised because the central authority becomes a single point of failure

Engineering Contradiction:
Improvekey managementVSAvoidsecurity
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent extracts the private key from the central authority's control and stores it locally in a secure element within the entity's own device. This eliminates the single point of failure at the central authority while maintaining simplified key management through automated enrollment and revocation processes.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the key management system into distributed components: the central authority manages public key infrastructure and revocation status, while individual entities maintain their own private keys in secure elements. This segmentation eliminates the single point of failure while preserving centralized coordination for revocation.

Inventive Principle:
Principle #1Segmentation

2Reliability

If private keys are stored locally in each entity, then security is improved by eliminating central vulnerability, but key revocation becomes difficult and slow

Engineering Contradiction:
ImprovesecurityVSAvoidrevocation timeliness
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent implements a feedback mechanism where entities periodically query the central authority for their revocation status, and the central authority provides real-time updates about key validity. This enables rapid propagation of revocation decisions to all entities in the system.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent performs preliminary actions by establishing secure key pairs and enrolling entities with the central authority before they need to operate. Revocation status is pre-configured and can be quickly updated and propagated without disrupting ongoing operations.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If private keys are stored locally, then security against central compromise is improved, but verification of key validity becomes more complex

Engineering Contradiction:
ImprovesecurityVSAvoidverification process
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces the central authority as an intermediary that issues digital certificates and maintains a certificate revocation list (CRL). Entities verify key validity by checking the CRL against their locally stored certificates, simplifying the verification process while maintaining security.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Reliability

If cryptographic identities are managed with traditional PKI, then security is maintained, but scalability is limited due to certificate management overhead

Engineering Contradiction:
ImprovesecurityVSAvoidscalability
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent enables entities to self-generate their own key pairs and self-enroll with the central authority using a standardized protocol. This eliminates the need for manual certificate management and enables automatic scaling as new entities join the network without increasing operational overhead.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4625883A1Systems and methods for cryptographic identity management in control systems
Publication Date: 2025.10.01 SCHNEIDER ELECTRIC SYSTEMS USA INC
  • EP4625883A1 patent drawingFigure 1
  • EP4625883A1 patent drawingFigure 2
  • EP4625883A1 patent drawingFigure 3

AI summary

Cryptographic identity management in an industrial control system. During a setup phase, a public key is defined and a private key is generated for a first entity while the first entity is in the non-operational mode. During an operational mode of the first entity, a second entity that is in a non-operational mode is identified. A public key is defined and a private key is generated for the second entity while the second entity is in the non-operational mode. Responsive to a request, an online identity status is transmitted to an entity (e.g., first or second entity), while the entity is in the operational mode. In this manner, the entity may be configured to use the online identity status to perform an encryption and/or a signature operation.