Flash Memory One-Time Read Security Mechanism

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Solution Overview

Problem

NAND flash memory devices face security risks due to repeated reading of sensitive information like security codes and private data, which can lead to unauthorized access and inadequate protection.

Innovation Solution

A semiconductor memory device with a novel structure that includes a NAND memory array, an input part for address and data, a setting part for specific address and data storage, and a control part that compares input address information with stored specific address information, allowing data to be read only once and then erased or invalidated, limiting subsequent access.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If sensitive information is stored in flash memory for repeated reading, then the information is readily accessible when needed, but the security level decreases due to multiple unauthorized access risks

Engineering Contradiction:

ImproveAccessibility of sensitive informationVSAvoidSecurity level of sensitive information

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent changes the accessibility parameter of stored information from 'repeatedly readable' to 'one-time readable'. The control circuit monitors read operations and automatically invalidates the stored information after a single authorized read, transforming the data accessibility state from permanent to temporary, thereby resolving the contradiction between ease of access and security protection

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent treats the stored sensitive information as a disposable resource that can be consumed only once. After the first read operation, the information is automatically erased or invalidated, making it unusable for subsequent reads. This approach protects security by ensuring that even if unauthorized access occurs after the first read, the information cannot be replicated or accessed again

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Reliability

If sensitive information is made accessible only during booting, then security is improved, but the time limitation becomes too restrictive for operational use

Engineering Contradiction:

ImproveSecurity level of sensitive informationVSAvoidTime flexibility for information access

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent introduces dynamic control over information accessibility. Instead of static time-based restrictions (only during booting), the system dynamically manages access based on read operation counts. The control circuit actively monitors and adjusts the accessibility state of stored information, allowing flexible access during operation while maintaining security through automatic invalidation after one read

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS9953170B2Semiconductor memory device, semiconductor system and reading method

Publication Date: 2018.04.24 WINBOND ELECTRONICS CORP

AI summary

The invention provides a flash memory which may effectively protect information with a high security level. A flash memory includes a setting part. When the setting part is inputted a specific command, the setting part sets up specific address information to a nonvolatile configuration register, and sets up specific data in a hidden storage region. The flash memory also includes: a comparing part, which compares inputted address information and the specific address information during a reading operation; and a control part, which reads specific data set in the storage region and erases a specific address when two address information are consistent, and reads data stored in a memory array according to the inputted address information when two address information are inconsistent.