Nonvolatile Memory Encryption via Threshold Voltage Randomness

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Solution Overview

Problem

Existing nonvolatile memory devices require a separate random number generator for data encryption, which increases costs and introduces potential vulnerabilities.

Innovation Solution

A method and device that generate random data based on the threshold voltage distribution of memory cells within the nonvolatile memory device, eliminating the need for a separate random number generator by using internally-generated random data for encryption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a separate random number generator is used for data encryption, then encryption functionality is achieved, but device complexity and cost increase

Engineering Contradiction:

Improvedata encryptionVSAvoidseparate random number generator

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the random number generation function with the existing memory cell array by utilizing the threshold voltage distribution characteristics of the memory cells. Instead of adding a separate random number generator, the system uses the inherent physical variations in memory cell threshold voltages to generate random data, thereby achieving encryption functionality while reducing device complexity and cost.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The memory cell array serves dual purposes: storing user data and generating random encryption keys. By exploiting the natural threshold voltage distribution of the memory cells, the system enables the memory device to self-generate random data without requiring external random number generation hardware, thus eliminating the need for separate components.

Inventive Principle:

Principle #25Self-service

2Reliability

If a separate random number generator is used for data encryption, then encryption functionality is achieved, but manufacturing cost increases

Engineering Contradiction:

Improvedata encryptionVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent combines the random number generation capability with the existing memory cell array structure. By utilizing the threshold voltage distribution of memory cells that already exist in the device, the system eliminates the need for additional random number generation hardware, thereby reducing manufacturing costs while maintaining encryption functionality.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The memory cell array is designed to perform multiple functions: storing user data and generating random encryption keys. This multi-functional approach allows the same hardware component to serve dual purposes, reducing the overall bill of materials and manufacturing complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If a separate random number generator is used for data encryption, then random data generation is achieved, but potential security vulnerabilities are introduced

Engineering Contradiction:

Improverandom data generationVSAvoidsecurity vulnerability

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the random data generation capability from separate hardware and embeds it within the memory cell array's inherent physical characteristics. By using the threshold voltage distribution of memory cells as the source of randomness, the system removes the separate random number generator component that could potentially introduce security vulnerabilities.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The memory device uses its own internal physical characteristics (threshold voltage distribution of memory cells) to generate random data, rather than relying on external or separate random number generation hardware. This self-service approach reduces the attack surface by eliminating additional components that could be targeted by security threats.

Inventive Principle:

Principle #25Self-service

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 approach reduces costs and removes the vulnerability of a separate random number generating circuit, while maintaining effective data encryption within nonvolatile memory devices.

Implementation Method 1

randomness of the random data is based on a threshold voltage distribution of the selected memory cells

Methodology Applied

Scientific EffectThreshold voltage distribution:

Implementation Method 2

programming data in selected memory cells among the memory cells

Methodology Applied

Scientific EffectCharge storage in memory cells:

Data Source

PatentUS11567879B2Method of encrypting data in nonvolatile memory device, nonvolatile memory device and user device

Publication Date: 2023.01.31 SAMSUNG ELECTRONICS CO LTD

AI summary

A method of encrypting data in a nonvolatile memory device (NVM) includes; programming data in selected memory cells, sensing the selected memory cells at a first time during a develop period to provide random data, sensing the selected memory cells at a second time during the develop period to provide main data, encrypting the main data using the random data to generate encrypted main data, and outputting the encrypted main data to an external circuit, wherein the randomness of the random data is based on a threshold voltage distribution of the selected memory cells.