Electronic Chip with Dynamic Resistance for Attack Protection

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Solution Overview

Problem

Electronic chips containing confidential information, such as bank card chips, are vulnerable to attacks from the rear face, where attackers can access circuit elements like transistors and conductive tracks to extract information, and existing methods like resistance detection for faulty microchips are insufficient in protecting against such attacks.

Innovation Solution

The implementation of an electronic chip with a serpentine-shaped resistive region and selector switches that connect to a node, allowing a selectable number of zones to be contacted, and a detector to compare measured and expected electrical resistance values, with the expected value randomly selected to thwart attack detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a fixed resistance value is used in the chip, then the manufacturing process is simple, but attackers can predict and exploit the resistance value to extract information

Engineering Contradiction:
Improvesecurity protectionVSAvoidresistance value management
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies dynamics by making the resistance value changeable rather than fixed. The system dynamically selects different resistance values from multiple available values based on random numbers generated during operation, preventing attackers from predicting or exploiting a static resistance value. This is achieved through the resistance value selection module that switches between different resistance values in response to control signals.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the resistance parameter from a fixed value to a variable value. By maintaining multiple resistance values and selectively switching between them, the system transforms the resistance from a constant physical parameter to a dynamic parameter that can be adjusted based on operational requirements and security considerations.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If resistance detection method is used for faulty microchips, then some detection capability is provided, but it is insufficient to protect against rear face attacks and information extraction

Engineering Contradiction:
Improveattack protectionVSAvoidattack detection capability
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent applies preliminary action by performing resistance value changes before an attack can occur. The system proactively varies resistance values during normal operation and before any potential attack attempt, making it impossible for attackers to plan or execute successful exploitation. The resistance value is changed in response to random numbers generated in advance of any attack scenario.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system incorporates feedback mechanisms where the resistance value selection is based on randomly generated numbers that create unpredictable patterns. This feedback loop ensures that the resistance value continuously adapts to new conditions, making it extremely difficult for attackers to detect or measure consistent patterns that would reveal confidential information.

Inventive Principle:
Principle #23Feedback

3Ease of manufacture

If the resistive region structure is simplified, then manufacturing is easier, but the ability to provide selectable resistance values is reduced

Engineering Contradiction:
Improvechip fabricationVSAvoidresistance value selection
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent applies segmentation by dividing the resistive region into multiple separate resistive elements or zones, each providing a different resistance value. Instead of using a single complex variable resistor structure, the system segments the resistance into discrete controllable portions that can be independently selected through switching mechanisms, simplifying the overall manufacturing process while maintaining versatility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent resolves the contradiction by moving from a single-dimension resistance control to a multi-dimensional approach. Instead of varying resistance within a single continuous element, the system uses discrete resistance values achieved through combining or selecting from multiple resistive elements, effectively adding a dimensional aspect to resistance control that simplifies manufacturing while preserving adaptability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 solution effectively protects the chip against attacks by randomly changing the expected resistance values, making it impossible for attackers to access confidential information, even with attempts to adjust resistors, thereby enhancing security.

Implementation Method 1

a resistive region (102) in contact with a selectable number of first zones (106-k)

Methodology Applied
Scientific EffectElectrical resistance: Electrical Resistance

Implementation Method 2

a detector of a difference between measured and expected values of electrical resistance between the first and second zones

Methodology Applied
Scientific EffectElectrical resistance measurement: Electrical Resistance

Data Source

PatentEP3570200B1Electronic chip
Publication Date: 2022.03.09 STMICROELECTRONICS (ROUSSET) SAS
  • EP3570200B1 patent drawingFigure 1
  • EP3570200B1 patent drawingFigure 2
  • EP3570200B1 patent drawingFigure 3

AI summary

The invention relates to an electronic chip comprising a resistive region (102) and a first switch (120) for selecting a first zone in contact with the resistive region.