Secure Element Key Derivation for Isolated Root Key Protection

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Solution Overview

Problem

Existing security architecture systems in computing devices face vulnerabilities in managing and protecting important resources such as 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 derives keys from stored root keys in secure element subsystems, using a hardware isolation mechanism to ensure secure key operations, replacing direct use of root keys with derived keys to limit security risks and enable cryptographic operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

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

Engineering Contradiction:

Improvesecurity of key storageVSAvoidrisk of key leakage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent segments the key management system into multiple components: root keys stored in the secure element subsystem, derived keys generated for specific applications, and access authority mechanisms. This segmentation ensures that even if one derived key is compromised, the root keys and other derived keys remain secure, thus resolving the contradiction between maintaining security and preventing key leakage.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary mechanism (the key derivation and access control system) between the root keys and the applications. Instead of direct access to root keys, applications must obtain derived keys through authorized requests. This intermediary layer protects the root keys from direct attacks while still enabling cryptographic operations, resolving the security vulnerability.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If derived keys are generated for each application, then the impact of key leakage is limited to specific applications, but the key management system becomes more complex

Engineering Contradiction:

Improvesecurity isolation of key leakageVSAvoidcomplexity of key management system

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a universal key derivation mechanism that serves multiple applications through a single secure element subsystem. The system can generate different derived keys for different applications while maintaining a unified management structure. This multi-functionality approach limits key leakage impact to specific applications without requiring separate key management systems for each application, thus balancing security isolation with system complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If access authority verification is implemented before key derivation, then unauthorized access is prevented, but the key management process requires additional verification steps

Engineering Contradiction:

Improveaccess control securityVSAvoidsimplicity of key derivation process

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent implements preliminary access authority verification before key derivation is performed. The system checks whether the requesting application has the necessary access authority to the root key before generating a derived key. This preliminary action prevents unauthorized access while streamlining the process for authorized applications, balancing security verification with operational simplicity.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentEP4187425B1Key management method, key management device, and computing device

Publication Date: 2026.02.18 PHYTIUM TECH CO LTD

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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.