Charge Storage Circuitry for Side Channel Attack Protection

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Solution Overview

Problem

Electronic circuitry is vulnerable to side channel attacks, which aim to extract information by analyzing changes in physical parameters such as power or energy consumption, posing a risk to security and safety-critical functions.

Innovation Solution

The implementation of a charge storage circuitry that provides isolated power to protected circuitry using a network of capacitors and switches, decoupling the local power supply from the global power supply to obscure variations in voltage, current, or power consumption, thereby reducing the visibility of processing activities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If protected circuitry is directly connected to global power supply, then power distribution is simple and efficient, but power consumption variations reveal processing activities to side channel attacks

Engineering Contradiction:
ImprovesecurityVSAvoidpower distribution complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces charge storage circuitry as an intermediary between the global power supply and protected circuitry. This intermediary decouples the direct connection, allowing power to be transferred through stored charge rather than direct conductive paths, thereby masking power consumption variations and preventing side channel attacks while maintaining power distribution functionality

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The power distribution system is segmented into multiple independent charge storage circuits, each capable of isolating specific portions of the protected circuitry from the global power supply. This segmentation allows selective isolation of vulnerable circuits while maintaining power supply to non-sensitive portions, balancing security requirements with system functionality

Inventive Principle:
Principle #1Segmentation

2Reliability

If charge storage circuitry is used to isolate power supply, then side channel attack vulnerability is reduced, but power distribution complexity increases

Engineering Contradiction:
ImprovesecurityVSAvoidpower distribution complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Multiple charge storage circuits are merged into a coordinated system where they collectively provide isolation for the entire protected circuitry block. The circuits work in unison under centralized control, sharing common control signals and coordination mechanisms, which reduces the overall complexity compared to implementing separate isolation circuits for each individual circuit element

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The charge storage circuitry serves multiple functions simultaneously: it acts as a power buffer, an isolation barrier, and a control element. By combining these functions into a single multi-functional component, the patent reduces the need for separate dedicated circuits for each function, thereby managing complexity while achieving security goals

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If multiple charge storage circuits are used to provide isolated power, then power isolation effectiveness is improved, but circuit complexity increases

Engineering Contradiction:
Improvepower isolation effectivenessVSAvoidcircuit complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The charge storage circuits are configured with asymmetric roles where certain circuits are dedicated to charging phases while others are dedicated to discharging phases. This asymmetric allocation optimizes the isolation effectiveness by ensuring that at least one circuit is always in a state that provides isolation, while the other circuits perform complementary functions, thereby achieving enhanced isolation without proportionally increasing complexity

Inventive Principle:
Principle #4Asymmetry

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 reduces the vulnerability of protected circuitry to side channel attacks by masking power consumption patterns, ensuring that the protected circuitry operates with a constant power level and minimizing exposure of power variations on global supply lines.

Implementation Method 1

A first of the plurality of charge stores is capable of receiving power from the power input, and a second of the plurality of charge stores is capable of outputting power to the power output

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP3631938B1Efficient power distribution
Publication Date: 2023.03.29 ARM LTD
  • EP3631938B1 patent drawingFigure 1
  • EP3631938B1 patent drawingFigure 2
  • EP3631938B1 patent drawingFigure 3a~3b

AI summary

Power is received from a first power signal at a first of a plurality of charge stores. A second power signal is output from a second of the plurality of charge stores. The second power signal is isolated from the first power supply.