Fault Detection Timing Masking in Electronic Devices

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing countermeasures against fault attacks in electronic devices are vulnerable to attackers who can shut down the device or detect fault detection by monitoring operations in non-volatile memory, compromising the device's functionality and resilience.

Innovation Solution

The electronic device executes operations changing its internal state to indicate fault detection or non-detection after a predetermined period following the command execution, using randomization to mask the detection and randomize the timing of these operations, thereby preventing attackers from learning about fault detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the electronic device executes operations to change internal state indicating fault detection during command execution, then fault detection capability is improved, but the device becomes vulnerable to shutdown by attackers monitoring memory operations

Engineering Contradiction:

Improvefault detection capabilityVSAvoidvulnerability to attacker shutdown

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by pre-scheduling fault detection operations to execute after a predetermined time delay following command execution. Instead of immediately updating internal state when a fault is detected, the system schedules the state change operation to occur later, after the command execution window has closed. This allows the fault detection mechanism to operate while avoiding the vulnerable period where attackers can monitor memory operations and detect fault detection behavior.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If the electronic device masks fault detection by delaying internal state changes, then resilience to fault attacks is improved, but the timing of fault response becomes unpredictable

Engineering Contradiction:

Improveresilience to fault attacksVSAvoidunpredictable fault response timing

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent implements periodic action by using fixed, predetermined time delays for scheduling fault detection operations. The system establishes regular, predictable intervals between command execution and the subsequent internal state update operations. This periodic scheduling provides timing predictability within the delayed window, allowing the system to mask fault detection from attackers while maintaining controlled, repeatable timing behavior for fault response operations.

Inventive Principle:

Principle #19Periodic action

Data Source

PatentEP4654018A1Method for improving the resilience of an electronic device to fault attacks, corresponding computer program product and devices

Publication Date: 2025.11.26 NAGRAVISION SA

Figure 1~4

AI summary

A method is proposed for improving the resilience of an electronic device to fault attacks, the electronic device implementing a fault detection mechanism during the execution of a command. According to such method, the electronic device executes: - executing a command; and - executing, after a predetermined period of time counted from the end of the execution of the command, at least one operation changing the internal state of the electronic device to an internal state indicative that a fault was detected or not during the execution of the command.