Voltage-Variation Detection Circuits Under Clock Jitter

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Solution Overview

Problem

Electronic devices, particularly integrated circuits (ICs), face challenges in detecting voltage-based attacks under clock fluctuations, as the delay caused by voltage variations is masked by frequency fluctuations, making it difficult to distinguish between the two.

Innovation Solution

The implementation of two voltage-dependent circuits with different voltage sensitivities, which produce signals that react differently to voltage variations but similarly to clock signal fluctuations. These signals are combined to neutralize the delay characteristic due to clock fluctuations, allowing for the detection of voltage-based attacks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If clock fluctuations are introduced to combat physical attacks, then security against inference attacks is improved, but the ability to detect voltage-based attacks deteriorates due to masked signal delays

Engineering Contradiction:

Improvesecurity against inference attacksVSAvoiddetection of voltage-based attacks

Core Design Contradiction:

ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The detection system is segmented into multiple independent voltage-dependent circuits (first voltage-dependent circuit and second voltage-dependent circuit) that process clock signals separately. Each circuit produces its own signal with voltage sensitivity, allowing the system to segment the detection function to overcome the masking effect of clock fluctuations.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the voltage sensitivity parameter of the detection circuits by using circuits with different voltage sensitivities. This parameter differentiation allows the combined signal to neutralize clock fluctuation effects while preserving voltage attack detection capability, as the differential voltage sensitivity creates a detectable pattern despite frequency variations.

Inventive Principle:

Principle #35Parameter changes

2Difficulty of detecting and measuring

If voltage sensitivity of detection circuits is increased to improve attack detection, then detection capability is improved, but sensitivity to clock fluctuations also increases making detection more difficult

Engineering Contradiction:

Improvedetection capabilityVSAvoidsensitivity to clock fluctuations

Core Design Contradiction:

Difficulty of detecting and measuringVSObject-affected harmful factors

Solution Approach 1:

The invention introduces asymmetry in voltage sensitivity between the first and second voltage-dependent circuits. By designing circuits with deliberately different voltage sensitivity characteristics, the system creates an asymmetric response to voltage changes that distinguishes voltage attacks from symmetric clock fluctuations, enabling detection despite high voltage sensitivity.

Inventive Principle:

Principle #4Asymmetry

3Difficulty of detecting and measuring

If signal delay is used to detect voltage variations, then voltage attack detection is improved, but the measurement precision deteriorates due to interference from clock frequency variations

Engineering Contradiction:

Improvevoltage attack detectionVSAvoidsignal delay measurement

Core Design Contradiction:

Difficulty of detecting and measuringVSMeasurement precision

Solution Approach 1:

The combined signal produced by merging outputs from multiple voltage-dependent circuits acts as an intermediary that filters out clock fluctuation effects. This intermediary signal preserves the voltage-dependent delay characteristics while eliminating the frequency variation component, thereby improving measurement precision of voltage-induced delays.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

This approach enables effective detection of voltage-based attacks even in the presence of clock fluctuations, thereby enhancing the security of electronic devices by preventing unauthorized access to sensitive information.

Implementation Method 1

a propagating signal is delayed using circuitry that is sensitive to voltage

Methodology Applied

Scientific EffectSignal delay in voltage-dependent circuits:

Implementation Method 2

frequency fluctuations of a clock signal, or clock fluctuations, are intentionally created to combat against physical attacks on an IC chip

Methodology Applied

Scientific EffectClock fluctuations:

Data Source

PatentUS12332283B2Voltage-variation detection under clock fluctuations

Publication Date: 2025.06.17 GOOGLE LLC

AI summary

Detecting voltage-based attacks on an integrated circuit (IC) is difficult in the presence of clock jitter. Propagating signals can exhibit a total delay that is due to a delay component resulting from a voltage-based attack and a delay characteristic resulting from clock fluctuation. Voltage-variation detection circuitry includes first and second voltage-dependent circuits and a voltage analysis circuit. The voltage-dependent circuits produce first and second signals that are indicative of a voltage level responsive to a clock signal and based on different first and second voltage sensitivities. The voltage analysis circuit generates a voltage alert signal based on the first and second signals. A combined signal neutralizes the delay characteristic in the first and second signals, but the delay component due to the voltage variation can be at least partially maintained. Thus, a voltage-based attack is detectable in the presence of clock fluctuation by using two voltage-dependent circuits.