Chip Flip-Flop Architecture for Fault Injection Detection

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Solution Overview

Problem

Electronic chips, such as bank card chips, are vulnerable to fault injection attacks where hackers disrupt operations using laser pulses or high voltages, making existing protection methods ineffective and difficult to implement.

Innovation Solution

The chip design incorporates a semiconductor substrate with buried slabs and polarizable wells, featuring MOS transistors and a detection circuit that initializes flip-flops and detects changes in logic levels, triggering countermeasures to stop attacks, thereby protecting against laser and voltage-based disruptions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If complex protection methods are used to counter fault injection attacks, then security reliability is improved, but device complexity increases and implementation becomes difficult

Engineering Contradiction:
Improvesecurity protectionVSAvoidimplementation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex analog protection circuits with a simplified digital detection system. The detection circuit monitors logic levels of flip-flops and triggers countermeasures through digital signals, avoiding the need for complex analog components while maintaining effective protection against fault injection attacks

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The detection circuit automatically monitors the logic levels of flip-flops and autonomously triggers countermeasures when attacks are detected, eliminating the need for external complex protection systems. The system serves itself by using its own internal state changes as the basis for detecting attacks and initiating responses

Inventive Principle:
Principle #25Self-service

2Measurement precision

If analog components are used for protection, then detection capability is improved, but manufacturing precision requirements increase and implementation becomes more difficult

Engineering Contradiction:
Improveattack detectionVSAvoidcomponent fabrication
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The patent substitutes analog detection components with digital logic elements. The detection circuit uses digital logic to monitor flip-flop states, which are inherently binary and robust to manufacturing variations. This eliminates the need for precise analog component matching while maintaining high detection precision for attack events

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If simple protection methods are used, then device complexity is reduced, but protection effectiveness against fault injection attacks deteriorates

Engineering Contradiction:
Improvestructure simplicityVSAvoidattack resistance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The detection circuit continuously monitors the logic levels of flip-flops and provides feedback to trigger countermeasures when attack-induced changes are detected. This feedback mechanism enables simple yet effective protection by using the system's own operational states as the basis for detecting external attacks

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent implements preliminary protection by designing the detection circuit to monitor flip-flop states before attacks can compromise the system. The countermeasures are pre-configured to trigger automatically upon detection, providing immediate protection without requiring complex real-time analysis

Inventive Principle:
Principle #10Preliminary action

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 design effectively counters various fault injection attacks by quickly detecting and responding to changes in logic levels, ensuring the chip's sensitive circuits remain secure without requiring complex analog components, providing robust and simple-to-implement protection.

Implementation Method 1

a well of the second conductivity type, polarizable, which extends from the front side of the substrate to the buried slab; a circuit for detecting a change in logic level of one of the flip-flops

Methodology Applied
Scientific EffectElectrical potential detection: Electric Field

Implementation Method 2

The laser's impact disrupts the chip's operation, and the hacker conducts his attack by observing the consequences of these disturbances, called faults, on the activity of the chip's circuits

Methodology Applied
Scientific EffectPhotoconductivity: Photoconductivity

Implementation Method 3

a first channel MOS transistor of the first conductivity type, the first transistor being an element of said at least one flip-flop

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP3373330B1Electronic chip architecture
Publication Date: 2024.06.19 STMICROELECTRONICS (ROUSSET) SAS
  • EP3373330B1 patent drawingFigure 1A~1B
  • EP3373330B1 patent drawingFigure 2~3

AI summary

The invention relates to an electronic chip comprising: a semiconductor substrate (102) doped with a first type of conductivity; wells (104) of the second conductivity type on the side of the front face of the chip, in and on which circuit elements are formed; one or more slabs (110) of a second type of conductivity buried under the boxes and separated from the boxes; for each buried slab, a well (114) of the second type of conductivity, polarizable, which extends from the front face of the substrate to the buried slab; in the upper part of each well, a first channel MOS transistor of the first type of conductivity, the first transistor being an element of a flip-flop; and a circuit for detecting a change in logic level of one of the flip-flops.