Secure Element Key Derivation Under Hardware Isolation

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Solution Overview

Problem

Existing security architecture systems in computing devices face vulnerabilities in managing and protecting important resources like root keys due to potential attacks or malicious access, leading to information leakage, especially in secure element subsystems.

Innovation Solution

Implement a key management method that generates derived keys based on root keys stored in secure element subsystems, using a hardware isolation mechanism to prevent direct use of root keys, ensuring security by limiting exposure and enabling cryptographic operations with derived keys.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If root keys are stored directly in the secure element subsystem for cryptographic operations, then cryptographic operations can be performed, but the system is vulnerable to attacks and malicious access leading to key leakage

Engineering Contradiction:

Improvesecurity of root keyVSAvoidrisk of key leakage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent segments the root key into multiple key shares and stores them in different secure elements. No single secure element contains the complete root key, making it impossible to extract the full key through attacks on individual elements. This segmentation resolves the contradiction by maintaining security (reliability) while reducing the harmful factor of key leakage risk.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces key derivation functions and secure multi-party computation protocols as intermediaries between the stored key shares and the cryptographic operations. These intermediaries enable cryptographic operations to be performed on derived keys rather than directly on root keys, maintaining security while enabling functionality.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If derived keys are used instead of root keys for cryptographic operations, then the security is enhanced by limiting exposure, but the system complexity increases

Engineering Contradiction:

Improvesecurity of key managementVSAvoidkey management system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent performs preliminary key derivation to generate derived keys before cryptographic operations are needed. Key shares are pre-stored in secure elements, and derived keys are generated on-demand through secure computations. This preliminary preparation reduces the complexity of managing root key security while maintaining enhanced security through derived key usage.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The secure element subsystem autonomously performs key derivation operations using stored key shares without requiring external access to root keys. The system self-manages the generation and protection of derived keys, reducing operational complexity while maintaining security enhancements.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS12468858B2Key management method, key management device, and computing device

Publication Date: 2025.11.11 PHYTIUM TECH CO LTD

AI summary

A security architecture method suitable for a security architecture system is provided. The security architecture system includes a first execution environment subsystem and a secure element subsystem. The secure element subsystem is configured to store a key. A hardware isolation mechanism is arranged between the secure element subsystem and the first execution environment subsystem. The method includes: obtaining a key derivation request from the first execution environment subsystem, the key derivation request carrying key identifier information; and allowing a derived key to be generated by using the key corresponding to the key identifier information in response to the first execution environment subsystem have an access authority to access the key corresponding to the key identifier information. The derived key is used to perform a cryptographic operation.