Tamper-Protected Execution Environment for Secure Code Verification
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Solution Overview
Problem
There is a lack of efficient and versatile methods to detect and respond to malicious changes in program code, particularly in field devices and control units with reloadable code, which are vulnerable to manipulation and security threats, especially during runtime.
Innovation Solution
An execution environment with a function memory for storing verification functions, a configuration memory protected by a tamper detection module, and an execution unit that checks program code against execution requirements, ensuring secure execution by verifying the integrity of the code and environment before execution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If program code is made reloadable to support dynamic applications, then adaptability is improved, but security and reliability deteriorate due to increased vulnerability to malicious code and manipulation
Solution Approach 1:
The patent applies preliminary action by verifying the integrity of program code and execution environment before execution. The system checks checksums of program code, configuration memory, and execution environment components prior to allowing execution, preventing malicious code from running while maintaining reloadable functionality.
Solution Approach 2:
The patent introduces an intermediary verification mechanism between program code loading and execution. The checksum verification system acts as a mediator that validates both the program code and execution environment, ensuring security without preventing dynamic code reloading.
2Reliability
If runtime verification of program code is implemented, then security is improved, but device complexity increases due to additional verification components
Solution Approach 1:
The patent applies universality by designing verification functions that can check multiple targets (program code, configuration memory, execution environment) using a unified checksum-based approach. This multi-functional verification system reduces overall complexity compared to separate verification mechanisms for each component.
Solution Approach 2:
The patent uses parameter changes by implementing checksum verification that compares computed values against stored reference values. This parameter-based verification approach provides comprehensive security checking through a relatively simple computational mechanism.
3Reliability
If configuration memory is protected by tamper detection module, then security is improved, but ease of operation deteriorates due to restricted access
Solution Approach 1:
The patent applies dynamics by implementing conditional access to configuration memory based on verification results. The system dynamically adjusts accessibility - restricting access when verification fails but allowing normal operation when verification succeeds, balancing security with operational ease.
Data Source
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Figure 3
AI summary
The invention relates to a method and an execution environment to prevent, for example, the execution of manipulated program code on field devices.