Always-On Buffer Fault Detection for IC Supply Glitch Attacks

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Solution Overview

Problem

Conventional fault detection systems in integrated circuits (ICs) are area and power inefficient due to the use of analog components, limiting their effectiveness against various fault injection attacks, and are not operational during the booting process, leaving the IC vulnerable.

Innovation Solution

An IC design incorporating a digital always-on buffer and logic circuit that detects fault injection attacks by monitoring a secondary global supply voltage, allowing for broader attack detection and reduced area and power consumption, with integrated recovery mechanisms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If analog components (voltage reference generators, delay lines, comparators) are used in the fault detector, then the fault detection capability is improved, but the area occupied by the fault detector increases significantly

Engineering Contradiction:

Improvefault detection capabilityVSAvoidarea occupied by fault detector

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent replaces analog components (voltage reference generators, delay lines, comparators) with digital components (always-on buffer, logic circuit). This substitution fundamentally changes the detection mechanism from analog voltage comparison to digital logic state monitoring, thereby reducing the area occupied by the fault detector while maintaining fault detection capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the operating parameters of the fault detector by using a digital always-on buffer that operates at reduced supply voltage (second global supply voltage less than first global supply voltage). This parameter change allows the buffer to remain operational during booting and detect faults across different voltage conditions without requiring large analog components.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If analog components with continuous switching are used in the fault detector, then the fault detection function is maintained, but the dynamic power consumption increases significantly

Engineering Contradiction:

Improvefault detection functionVSAvoiddynamic power consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent replaces analog components with continuous switching (which consume dynamic power) with digital components that can operate in static states. The always-on buffer and logic circuit detect faults by monitoring logic states rather than continuously switching analog signals, thereby significantly reducing dynamic power consumption while maintaining the fault detection function.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If the fault detector is not enabled during the booting process, then the IC can be powered up, but the IC is unprotected during a portion of the booting process

Engineering Contradiction:

Improvepower up capabilityVSAvoidprotection during booting

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent implements an always-on buffer that is enabled before the main IC operation begins, specifically during the booting process. This preliminary action ensures that the fault detection mechanism is already active and monitoring when the IC is most vulnerable, without requiring additional power management complexity that would hinder the power-up process.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses a second global supply voltage that is less than the first global supply voltage and is controlled based on power line characteristics. This parameter change allows the always-on buffer to operate at reduced voltage during booting, enabling fault detection functionality during the booting process without preventing the IC from powering up successfully.

Inventive Principle:

Principle #35Parameter changes

4Device complexity

If a fault detector is designed to detect exclusively power glitching attacks, then the detection logic is simplified, but the IC remains vulnerable to other types of fault injection attacks

Engineering Contradiction:

Improvedetection logic complexityVSAvoidattack type coverage

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent designs the fault detector with universal applicability by using an always-on buffer and logic circuit that can detect multiple types of fault injection attacks (power glitching, electromagnetic attacks, and others) rather than being specialized for only one attack type. The digital logic structure inherently monitors for various fault conditions, providing multi-functional protection without significantly increasing complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS12499281B2System for detecting fault injection attacks

Publication Date: 2025.12.16 NXP BV

AI summary

An integrated circuit (IC) that includes an always-on buffer and a power line is provided. The power line is routed on the IC such that a first end of the power line is at a first global supply voltage and a second end of the power line is at a second global supply voltage that is less than the first global supply voltage. The always-on buffer receives an input bit and the second global supply voltage and generates an output bit that has a same logic state as that of the input bit. During a fault injection attack, the second global supply voltage is altered such that the logic state of the output bit toggles while the logic state of the input bit remains same. Based on the toggling of the logic state of the output bit, the fault injection attack on the IC is detected.