Fault Injection Detection in Functional Circuitry via Stability Monitoring
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Solution Overview
Problem
Existing methods for detecting fault injection attacks in electronic circuitry are not effective in identifying deviations during normal operational conditions without requiring additional hardware or dedicated fault detection states.
Innovation Solution
The system utilizes existing functional circuitry that meets a Finite Impulse Response (FIR) condition, where stability of input signals during one interval guarantees stability of output signals during a subsequent interval, allowing for detection of fault injection attempts by monitoring deviations from this condition during normal operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing methods for detecting fault injection attacks are used, then fault detection capability is provided, but additional hardware or dedicated fault detection states are required
Solution Approach 1:
The patent makes existing functional circuitry perform dual functions: normal operational processing and fault injection detection. The functional circuitry monitors its own input and output signals during normal operation to detect faults, eliminating the need for separate dedicated detection hardware or states.
Solution Approach 2:
The functional circuitry performs self-monitoring by evaluating its own stability conditions. The circuit detects fault injection attempts by autonomously assessing whether unstable inputs during a first time interval correlate with unstable outputs during a second time interval, without requiring external detection mechanisms.
2Measurement precision
If dedicated fault detection states are implemented, then fault detection accuracy is improved, but operational efficiency is reduced due to state transitions
Solution Approach 1:
The patent enables continuous fault detection during normal operational states without requiring transitions to dedicated detection states. The functional circuitry continuously monitors signal stability relationships while performing its primary function, maintaining both operational efficiency and detection accuracy.
Solution Approach 2:
The circuit pre-establishes stability condition relationships between inputs and outputs during normal operation. By continuously evaluating whether unstable inputs correlate with unstable outputs according to pre-defined time interval relationships, the system maintains readiness to detect faults without needing to enter a separate detection state.
3Device complexity
If existing functional circuitry is used for detection, then hardware complexity is reduced, but the ability to detect attacks during normal operation is limited
Solution Approach 1:
The functional circuitry implements self-feedback monitoring by continuously evaluating the stability relationship between its own input and output signals. The circuit feeds back information about signal stability correlations to detect fault injection attempts, enabling detection during normal operation without additional hardware.
Data Source
AI summary
An apparatus for detecting fault injection includes functional circuitry and fault detection circuitry. The functional circuitry is configured to receive one or more functional input signals and to process the functional input signals so as to produce one or more functional output signals. The functional circuitry meets a stability condition that specifies that stability of a designated set of one or more of the functional input signals during a first time interval guarantees stability of a designated set of one or more of the functional output signals during a second time interval that is derived from the first time interval. The fault detection circuitry is configured to monitor the designated functional input and output signals, to evaluate the stability condition based on the monitored functional input and output signals, and to detect a fault injection attempt in response to detecting a deviation from the stability condition.