Trusted OS File Loading into Read-Only RAM Zone
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Solution Overview
Problem
There is a need for a method to securely load files into a shared RAM zone between a trusted execution environment and a general-purpose execution environment in electronic devices, ensuring isolation and security while allowing controlled access and usage of files between the two environments.
Innovation Solution
A method where the trusted operating system receives information about files, verifies their compliance with given criteria, and loads them into a read-only accessible RAM zone, creating a sharing list with integrity verification and certificates, allowing the general-purpose environment to access files in a read-only mode for use in the trusted environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a shared memory area is provided between trusted execution environment and general-purpose execution environment, then memory usage efficiency is improved, but security isolation is worsened
Solution Approach 1:
The shared memory area is segmented into read-only regions and read-write regions. The read-only region allows general-purpose applications to access files without modification capabilities, while the read-write region is restricted to trusted execution environment. This segmentation enables secure sharing by separating access permissions based on security requirements.
Solution Approach 2:
Different security qualities are applied to different parts of the shared memory. The read-only region has relaxed access controls allowing general-purpose access, while the read-write region maintains strict security controls. This local differentiation of security properties enables efficient sharing where needed while preserving security where required.
2Ease of operation
If files are loaded into writable RAM area in general-purpose execution environment, then ease of operation is improved, but security is worsened due to potential alterations
Solution Approach 1:
The patent segments the shared memory into read-only and read-write portions. Files that require security protection are placed in the read-only portion, allowing general-purpose applications to read and execute them without modification capability. This segmentation enables safe file sharing by preventing write access to critical files while maintaining read accessibility.
3Reliability
If files are loaded into read-only RAM area, then security is improved by preventing alterations, but ease of operation is worsened due to access restrictions
Solution Approach 1:
The shared memory is segmented into read-only region for security-critical files and read-write region for flexible files. The read-only region ensures file integrity by preventing modifications, while the read-write region provides operational flexibility for files that require updates. This segmentation resolves the contradiction by applying different access modes to different file types.
Solution Approach 2:
The shared memory area serves multiple functions: it acts as a secure storage for read-only files accessible by general-purpose applications, and as a flexible workspace for read-write operations within the trusted execution environment. This multi-functionality allows the same memory region to satisfy both security and operational requirements.
Data Source
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Figure 5
AI summary
The invention relates to a method for loading a file into RAM in an electronic device designed to operate in a trusted execution environment (TEE), due to the execution of a trusted operating system by a processor of the electronic device, or in a multipurpose execution environment (REE), characterized in that it comprises the following steps: - reception (E10), by the trusted operating system, of information (L1) identifying at least one file; - verification (E11), by the trusted operating system, of the conformity of the identified file to at least one given criterion; - if conformity is found, loading (E13) of the identified file into a read-only area (Z2) of RAM during operation in the multipurpose execution environment (REE). An associated electronic device is also provided.