Self-Signed Certificate Authority for Isolated Device Authentication

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Solution Overview

Problem

Existing certificate authority systems require external involvement for certificate creation and validation, which can be inconvenient and less secure when devices need to authenticate processes or applications across different systems without global connectivity.

Innovation Solution

A device can act as its own certificate authority by creating a self-signed root certificate and using it to issue derived certificates, allowing processes to authenticate and validate capabilities without relying on external authorities, using public/private key pairs and protocols like SSL/TLS for secure communication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a device uses an external certificate authority to create and validate certificates, then certificate validation follows established security protocols, but the system requires global connectivity and external dependencies which reduces security and convenience in isolated environments

Engineering Contradiction:
Improvecertificate validation reliabilityVSAvoidoperation in isolated environments
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The device performs certificate authority functions autonomously by generating self-signed certificates and maintaining a local trusted certificate store, eliminating the need for external certificate authorities and enabling operation in isolated environments without global connectivity

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The device acts as an intermediary certificate authority between processes and external systems, issuing derived certificates that bind process identities to public keys, thereby enabling secure authentication without requiring direct connection to external certificate authorities

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If a device acts as its own certificate authority to enable isolated operation, then connectivity requirements are reduced, but the complexity of certificate management increases

Engineering Contradiction:
Improveoperation in isolated environmentsVSAvoidcertificate management complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The certificate management system is segmented into distinct components: a self-signed root certificate for the device, derived certificates for individual processes, and a local trusted certificate store, allowing independent management and validation of each certificate type

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The device pre-generates a self-signed root certificate and establishes a local trusted certificate store before isolated operation begins, eliminating the need for real-time connection to external certificate authorities and simplifying subsequent certificate validation

Inventive Principle:
Principle #10Preliminary action

3Reliability

If external certificate authorities are used for certificate issuance, then centralized security management is maintained, but response time for certificate validation increases due to network dependencies

Engineering Contradiction:
Improvesecurity managementVSAvoidcertificate validation time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The device performs certificate validation locally using its self-signed root certificate and stored trusted certificates, eliminating network round-trips to external certificate authorities and reducing validation time to minimal processing delays

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

Trusted root certificates are pre-loaded into the device's local store before operation, enabling immediate validation without requiring real-time connection to external certificate authorities, thereby eliminating network-dependent delays

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2747377B1Trusted certificate authority to create certificates based on capabilities of processes
Publication Date: 2016.03.09 BLACKBERRY LTD
  • EP2747377B1 patent drawingFigure 1
  • EP2747377B1 patent drawingFigure 2
  • EP2747377B1 patent drawingFigure 3

AI summary

A device certificate (112,206,518) binds an identity of a first device (100,200,500) to a public key of the first device. The first device comprises a certificate authority service that creates for a process (104,220,530) on the first device a process certificate (102,224,538) certifying one or more capabilities of the process on the first device. The process certificate is presented to a second device (106,250,600). Upon validating the process certificate using the device certificate, the second device permits the process on the first device to have on the second device one or more of the verified certified capabilities.