Flash Memory Security Feature Generation via Cell Threshold Voltage Measurement
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Solution Overview
Problem
Flash memory storage devices lack effective security measures to prevent unauthorized data copying and access, especially after disassembly, as third-party software and controllers can still extract important data.
Innovation Solution
A method and device that generate a security feature based on the threshold voltages of cells in a flash memory block, using these characteristics to create a unique protection key by erasing and writing data in a controlled manner to establish and verify access permissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copy protection is implemented in flash memory, then data security is improved, but device complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing security features (such as checksums, hashes, or encryption keys) in a secure area of the flash memory before data storage. These pre-stored security features enable the memory controller to verify data integrity and authenticity without requiring complex real-time security computations, thus improving data security while managing device complexity through advance preparation.
2Reliability
If third-party access is prevented, then data security is improved, but ease of operation deteriorates
Solution Approach 1:
The patent uses an intermediary approach by introducing a memory controller as a trusted mediator between the host system and the flash memory. The memory controller handles all security-related operations, including verifying security features, managing encryption keys, and controlling data access. This intermediary layer abstracts the security complexity from the user, maintaining ease of operation while ensuring data security through centralized security management.
3Reliability
If security features are generated using cell characteristics, then data security is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies parameter changes by utilizing the inherent electrical characteristics (such as threshold voltages, programming voltages, or retention times) of flash memory cells as the basis for generating security features. Instead of requiring precise manufacturing tolerances, the system leverages the natural variations in cell parameters to create unique security fingerprints. This approach transforms manufacturing variability from a potential weakness into a security strength, improving data security without imposing stringent manufacturing precision requirements.
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
Ensures data security by generating an exclusive security feature that prevents unauthorized access by comparing the established security feature with a pre-stored one, ensuring only authorized data access is allowed.
Implementation Method 1
providing a predetermined voltage to the determined memory block to obtain a plurality of corresponding threshold voltages of a plurality of cells in the determined memory block
Data Source
AI summary
A method for generating a security feature of a flash memory includes determining a memory block from a plurality of memory blocks in the flash memory; erasing data of the determined memory block of the flash memory; providing a predetermined voltage to the determined memory block to obtain a plurality of corresponding threshold voltages of a plurality of cells in the determined memory block, wherein each of the corresponding threshold voltages corresponds to a characteristic of each cell in the determined memory block; and establishing a security feature based on the plurality of corresponding threshold voltages.