Microcontroller Protection Against Fault Injection Attacks
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Solution Overview
Problem
Existing countermeasures against fault injection attacks in secure electronic circuits, such as microcontrollers, can be compromised if an attacker repeatedly targets the area causing the reset and the conductors carrying the reset signals, allowing them to thwart the security measures and access sensitive information.
Innovation Solution
A method and protection circuit that detect malfunctions and execute multiple waves of countermeasures without interrupting the circuit's operation, with variable intervals, including blocking memory programming, outputs, and regenerating cryptographic keys, followed by a reinitialization that does not include a non-maskable interrupt in the first group of waves, and incorporates non-maskable interrupts in subsequent waves, with random durations to deceive the attacker about the reaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a reset is executed immediately upon detecting a malfunction to prevent information extraction, then the circuit security is improved, but the attacker can identify the reset area and conductors through repeated localized attacks, ultimately compromising the security
Solution Approach 1:
The patent applies dynamics by making the countermeasure execution dynamic and adaptive. Instead of a fixed immediate reset, the system executes multiple waves of countermeasures with variable intervals between them. The number of waves and interval durations can be adjusted based on the attack detection, making the system's response unpredictable and harder for attackers to exploit through repeated localized attacks.
Solution Approach 2:
The patent implements periodic action through the execution of multiple waves of countermeasures separated by variable intervals. Rather than a single immediate reset, the system performs periodic countermeasure waves that obscure the timing and location of the actual reset operation, preventing attackers from easily identifying critical circuit areas through repeated attacks.
2Difficulty of detecting and measuring
If multiple waves of countermeasures are executed without interrupting circuit operation to obscure the reaction, then the attacker's ability to identify the reaction zone is reduced, but the circuit remains vulnerable during the extended countermeasure execution period
Solution Approach 1:
The patent applies segmentation by dividing the countermeasure execution into multiple distinct waves rather than a single continuous operation. Each wave can include different countermeasure actions (such as blocking memory programming, blocking outputs, regenerating cryptographic keys), and the variable intervals between waves create gaps that make it difficult for attackers to correlate their attacks with specific countermeasure actions, while maintaining circuit security throughout.
3Adaptability or versatility
If the interval between countermeasure waves is made variable and random to deceive attackers, then the predictability of the circuit's reaction is reduced, but the timing and coordination of countermeasures becomes more complex
Solution Approach 1:
The patent applies parameter changes by varying the interval durations between countermeasure waves and making them random rather than fixed. This changes the temporal parameters of the countermeasure execution, making it unpredictable for attackers while managing complexity through predefined variable ranges and selection criteria for the number of waves and interval durations.
Data Source
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AI summary
This description relates to a method for protecting an electronic circuit and a microcontroller in which a malfunction is detected, several waves of countermeasures are executed without interrupting the operation of the circuit, the interval between two waves of countermeasures being variable, and causes a reset of the circuit.