Sensor System Pulse Width Tampering Detection

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Solution Overview

Problem

Electronic systems are vulnerable to tampering through clock manipulation attacks and other signal manipulations that compromise security by altering pulse widths, which existing technologies fail to effectively detect and mitigate.

Innovation Solution

A sensor system comprising a charge storage device controllably connected to a voltage source under the control of a signal under test, coupled with a readout circuit that determines pulse width changes by measuring the voltage across the charge storage device, allowing for the detection of tampering through comparison with a threshold voltage, and optionally using multiple sensors for consistency checks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If existing monitoring technologies are used, then general signal monitoring is possible, but pulse width tampering detection capability is insufficient

Engineering Contradiction:

Improvepulse width tampering detection capabilityVSAvoidsecurity against clock manipulation attacks

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent introduces a charge storage device as an intermediary element between the signal under test and the readout circuit. The CSD captures voltage information during the pulse width, converting the temporal parameter (pulse width) into a voltage value that can be precisely measured and compared, thereby enabling accurate tampering detection

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces traditional time-based measurement methods with a voltage-based measurement approach. By using the charge storage device to convert pulse width information into voltage levels, the system substitutes direct temporal measurement with electrical parameter measurement, achieving higher precision and reliability in tampering detection

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If multiple sensors are deployed for consistency checks, then detection reliability improves, but device complexity increases

Engineering Contradiction:

Improvedetection reliability through consistency checksVSAvoidnumber of sensors and comparison circuitry

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple sensing functions into a unified sensor architecture. The sensor integrates the charge storage device, readout circuit, and comparison logic into a single cohesive unit that can perform both individual signal monitoring and cross-sensor consistency checks, reducing overall system complexity while maintaining high reliability

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The sensor design incorporates multi-functionality, allowing the same sensor node to perform multiple tasks: monitoring its own signal pulse width, comparing its measurements with other sensors, and participating in consistency verification. This universal approach enables reliable detection without requiring separate dedicated circuits for each function

Inventive Principle:

Principle #6Universality (Multi-functionality)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Effectively monitors and detects pulse width tampering in electronic systems, enabling timely countermeasures against clock manipulation attacks and ensuring the integrity of sensitive signals by accurately identifying changes in pulse widths.

Implementation Method 1

A sensor and method of using the sensor are described herein that can be employed in an electronic system to monitor a signal and determine if tampering of the signal with respect to the pulse width of the signal has occurred

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

The readout circuit can determine whether the pulse width of the signal under test has changed greater than a threshold amount according to a voltage at the CSD

Methodology Applied

Scientific EffectVoltage measurement: Ohm's Law

Data Source

PatentUS11022637B2Detection of pulse width tampering of signals

Publication Date: 2021.06.01 ARM LTD

AI summary

A sensor system includes a sensor having a charge storage device controllably connected to a voltage source under control of a signal under test; and a readout circuit coupled to the charge storage device to determine whether the pulse width of the signal under test has changed greater than a threshold amount according to a voltage at the charge storage device. In some cases, the determination of whether the pulse width of the signal under test has changed includes determining whether the voltage satisfies a condition with respect to a comparison voltage. In some cases, the determination of whether the pulse width of the signal under test has changed is based on a propagation delay through a delay chain, where the propagation delay is dependent on the voltage.