Implicitly Attested CSR Generation for IoT Device Identity

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Solution Overview

Problem

Standardized Certificate Signing Request (CSR) formats, while ensuring interoperability and security, can increase code and data storage requirements, posing challenges for resource-constrained Internet of Things (IoT) devices.

Innovation Solution

The method involves generating an implicitly attested CSR by creating a message with a device's public key and identifier, generating a digest, signing it with the private key, and encoding it in a way that the CSR implicitly attests to the device's identity, using non-standard transformations or encodings recognizable only by a configured Certificate Authority (CA).

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If standardized CSR formats (PKCS #10, ASN.1) are used, then interoperability and security are ensured, but code and data storage requirements increase

Engineering Contradiction:

Improveinteroperability and securityVSAvoidcode and data storage requirements

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent extracts the essential security elements (public key, device identifier, signature) from the standardized CSR format and removes the complex ASN.1 encoding structure. This creates a simplified CSR format that retains only the critical components needed for security and authentication, thereby reducing code and storage requirements while maintaining core functionality.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the encoding parameters of the CSR from standardized ASN.1 format to a simplified custom format. By altering the structural parameters and encoding rules, the patent reduces the overhead while maintaining the essential security properties through cryptographic signatures and verified fields.

Inventive Principle:

Principle #35Parameter changes

2Quantity of substance

If simplified CSR formats are used, then code and data storage requirements are reduced, but device attestation capability is lost

Engineering Contradiction:

Improvecode and data storage requirementsVSAvoiddevice attestation capability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent performs preliminary attestation by embedding the device identifier and cryptographic signature directly in the simplified CSR format before submission. This preliminary action ensures that device identity is verified upfront, maintaining attestation capability without requiring the full standardized format.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces a cryptographic signature as an intermediary mechanism that bridges the simplified format and the attestation requirement. The signature acts as a mediator that provides verification capability, ensuring device identity can be authenticated even in the reduced format through digital signature validation.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS20250175325A1Method and apparatus for generating and using implicitly attested certificate signing requests

Publication Date: 2025.05.29 ARRIS ENTERPRISES LLC

AI summary

A method and apparatus for generating and processing implicitly attested Certificate Signing Requests (CSRs) is disclosed. In one embodiment, the method comprises generating a message having a public key of a key pair of a device and an identifier of a device; generating a digest of the message; signing the digest according to a private key of the key pair of the device; and encoding the signed digest and the public key to produce the CSR; wherein the CSR implicitly attests to the identity of the device according to at least one of the message, the digest, and the encoding.