Magnetic Memory Device Security Against External Field Reading

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Solution Overview

Problem

Magnetic memory devices using self-referenced reading operations are vulnerable to security attacks due to the ability to be read using external magnetic fields, compromising data security.

Innovation Solution

The magnetic memory device is designed to only be readable by passing an input signal through an internal field line, preventing external magnetic field-based reading and thus enhancing security by ensuring data can only be accessed internally.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If an external magnetic field is used to read the magnetic memory device, then reading operation can be performed without controller, but data security is compromised due to vulnerability to security attacks

Engineering Contradiction:
Improvereading operation without controllerVSAvoidsecurity attacks
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a controller as an intermediary component that mediates all read operations. The controller generates and applies magnetic fields through controlled field lines, acting as a necessary intermediary between external systems and the magnetic memory device. This eliminates direct external magnetic field access while maintaining controlled reading operations, thus resolving the security vulnerability without sacrificing operational capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If magnetic memory device allows external magnetic field reading, then device simplicity is maintained, but reliability decreases due to security vulnerabilities

Engineering Contradiction:
Improvedevice structureVSAvoiddata security
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent segments the magnetic memory device into distinct functional components: storage units, field lines, and a controller. This segmentation isolates the sensitive magnetic storage elements from direct external access by introducing the controller as a separate management layer. The controller handles all magnetic field generation and read operations, creating a security boundary that protects the core storage units while maintaining device functionality.

Inventive Principle:
Principle #1Segmentation

3Object-affected harmful factors

If internal field line control is implemented for reading, then security against external attacks is improved, but device complexity increases due to controller requirements

Engineering Contradiction:
Improveexternal magnetic field attacksVSAvoidcontroller and field line structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The controller is designed as a universal management unit that handles multiple functions: generating magnetic fields for read operations, controlling field line activation, managing data retrieval protocols, and implementing security measures. This multi-functional design consolidates what could be multiple separate components into a single controller unit, reducing overall system complexity while maintaining comprehensive security and operational control.

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

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 ensures that the magnetic memory device can only be read by using an input signal, thereby preventing unauthorized access and enhancing security against external magnetic field-based attacks.

Implementation Method 1

The field line 4 is configured to provide, during a read operation, an input signal 41 generating a first magnetic field 42 adapted for varying the first sense magnetization 210

Methodology Applied
Scientific EffectElectromagnetic field generation: Electromagnet

Implementation Method 2

The magnetic tunnel junction 2 is configured such that a magnetization direction of the sense layer 21 and a resistance of the magnetic tunnel junction 2 vary based on the magnetic field 42

Methodology Applied
Scientific EffectMagnetoresistance effect: Magnetoresistance

Data Source

PatentEP3115994B1Magnetic memory device that is protected against reading using an external magnetic field and method for operating such magnetic memory device
Publication Date: 2022.06.08 CROCUS TECHNOLOGY
  • EP3115994B1 patent drawingFigure 1
  • EP3115994B1 patent drawingFigure 2(a)~3(b)
  • EP3115994B1 patent drawingFigure 4(a)~5(b)

AI summary

A magnetic memory device (100) comprising a plurality of magnetic units (1), each unit including a first and second magnetic tunnel junctions (2, 2') electrically connecting in series by a current line (3) and a strap (7), each magnetic unit comprising a first and second storage layer (23, 23') having a first and second storage magnetization (230, 230') and a first and second sense magnetic layer (21, 21') having a first and second senses magnetization (210, 210'); a field line (4) configured to provide an input signal (41) generating a first and second magnetic field (42, 42') for varying the first and second sense magnetization (210, 210'); each magnetic unit (1) being provided with a data state such that the first and second storage magnetizations (230, 230') are aligned in opposed directions; the first and second magnetic field (42, 42') being adapted for varying respectively the first and second sense magnetization (210, 210') in a first and second direction opposed to the first direction.