Security Manager for Nested Function Execution
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Solution Overview
Problem
Existing microprocessor-based data cards, such as bank cards, face security vulnerabilities due to fraudulent interference with the execution of nested functions, particularly in authentication processes, where fraudsters can disrupt the decrementing counter function or cause unexpected microprocessor behavior, allowing unauthorized access to sensitive information.
Innovation Solution
A method is implemented where a security manager program maintains a list of functions in progress, signaling start and end of execution, and checks for proper function sequencing, triggering protective actions if anomalies are detected, using a table with function identifiers and associated security levels to manage protection actions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a security manager program is implemented to monitor and check function execution sequencing, then security against fraudulent interference is improved, but device complexity and computational resource usage increase
Solution Approach 1:
A security manager program is introduced as an intermediary component that monitors function execution sequencing. This mediator maintains a list of functions in progress and verifies that function calls and returns follow the correct nested sequence, preventing fraudulent interference without requiring fundamental changes to the microprocessor architecture
Solution Approach 2:
The security manager pre-establishes a list of functions in progress before execution anomalies can occur. By maintaining this list and checking sequencing in advance, the system prevents fraudulent operations rather than detecting them after damage is done, reducing the need for complex post-hoc analysis
2Reliability
If a security manager program is implemented to monitor and check function execution sequencing, then security against fraudulent interference is improved, but processing speed and execution efficiency decrease
Solution Approach 1:
The security manager performs only essential partial checks - maintaining a list of functions in progress and verifying basic call/return sequencing. By implementing minimal necessary monitoring rather than comprehensive analysis of all execution parameters, the system achieves adequate security with limited impact on processing speed
3Ease of operation
If the counter decrement function is not protected, then ease of operation is maintained, but security vulnerabilities increase allowing unauthorized access
Solution Approach 1:
The security manager automatically monitors and protects the counter decrement function without requiring user intervention. The system self-verify that function calls and returns are properly sequenced, preventing fraudulent attempts to bypass the counter while maintaining transparent operation for legitimate users
Data Source
Figure 1~3
AI summary
Method of securing execution of a main program implementing nested functions, comprising the steps of: - executing a security manager program devised so as to update a list of functions in progress, - signalling a beginning of execution of each function to the security manager program and updating the list of functions in progress, - signalling an end of execution of each function to the security manager program, - verifying after each signalling of end of execution of a function that this function is indeed the last one to have begun and in the converse case performing a protection action.