Security Processor Stuck-At Fault Detection via Double Identifier Comparison
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Solution Overview
Problem
Security processors without explicit fail-safe hardware provisions can experience 'stuck-at' faults, where they consistently produce the same result, leading to incorrect verification of identifiers, which is challenging to detect without additional hardware.
Innovation Solution
Implementing a double execution mechanism at the security processor, where a first operation compares a second identifier with a first identifier, and a second operation compares the second identifier with a modified first identifier, allowing the master processor to assess the results and determine the validity of the identifier and the security processor's functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single identifier comparison operation is performed at the security processor, then the verification process is simple and fast, but stuck-at faults cannot be detected
Solution Approach 1:
The patent applies preliminary action by performing a first comparison operation between the calculated second identifier and the first identifier before performing a second comparison operation between the second identifier and a modified first identifier. This preliminary sequence of operations enables stuck-at fault detection without requiring additional hardware, thereby improving reliability while maintaining operational simplicity
Solution Approach 2:
The verification process is segmented into two distinct comparison operations: a first operation comparing the second identifier with the first identifier, and a second operation comparing the second identifier with a modified first identifier. This segmentation allows the system to detect stuck-at faults by analyzing the differential results of separate comparison operations, resolving the contradiction between simplicity and fault detection capability
2Reliability
If additional hardware is added to detect stuck-at faults, then fault detection capability is improved, but device complexity and cost increase
Solution Approach 1:
The security processor performs self-verification by executing multiple comparison operations using its existing hardware resources. The processor compares the calculated second identifier against both the original first identifier and a modified first identifier, enabling self-detection of stuck-at faults without external assistance or additional detection hardware, thus maintaining device simplicity while improving reliability
Solution Approach 2:
The patent changes the parameter being compared by introducing a modified first identifier (such as an inverted or transformed version of the original identifier) for the second comparison operation. This parameter variation enables the detection of stuck-at faults through differential analysis of comparison results, achieving fault detection capability without adding hardware complexity
Data Source
AI summary
An embodiment relates to a method for processing data that includes (a) calculating a second identifier based on input data, (b) conducting a first operation comparing the second identifier with a first identifier, and (c) conducting a second operation comparing the second identifier with a modified first identifier.