Flash Memory PUF Quantized Signal Generation via Threshold Voltage Segmentation
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Solution Overview
Problem
Conventional PUF devices are vulnerable to external attacks due to limited randomness in their challenge-response pairs, which can be exploited, and they incur additional costs for detection devices and may face side-channel attacks.
Innovation Solution
A flash memory system that generates a quantized signal using physical characteristics, such as threshold voltage distributions, to enhance randomness and defend against external attacks by employing a memory controller that programs memory blocks with varying program voltages and uses a map table to manage combination order information and threshold voltage states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional PUF device uses a single challenge-response pair, then the device structure is simple, but the randomness is limited and the device becomes vulnerable to external attacks
Solution Approach 1:
The patent divides the challenge-response mechanism into multiple segments by applying multiple reference read voltages to create multiple quantization intervals. Each interval generates a separate quantized bit, transforming a single challenge-response pair into multiple quantized bits from one challenge, thereby enhancing randomness and security without requiring multiple separate PUF devices
Solution Approach 2:
The patent introduces a new dimension to the challenge-response mechanism by adding voltage dimensionality. Instead of using a single reference voltage level, multiple reference read voltages are applied to create multiple quantization intervals along the voltage axis, enabling the generation of multiple quantized bits from a single challenge and significantly increasing the randomness of the system
2Reliability
If additional detection devices are added to protect against external attacks, then security is improved, but additional cost is incurred
Solution Approach 1:
The flash memory system performs its own authentication function by utilizing its inherent physical characteristics (threshold voltage distributions) to generate quantized signals. The system serves as both the storage medium and the PUF device, eliminating the need for separate detection devices and reducing additional costs while maintaining security
3Reliability
If a PUF device is opened and analyzed, then the internal configuration can be viewed, but physically cloneable circuits with the same output cannot be implemented due to process variations
Solution Approach 1:
The patent exploits parameter variations (threshold voltage distributions) that naturally occur during the flash memory manufacturing process. By applying multiple reference read voltages and measuring the quantization responses across different voltage levels, the system captures these process variations to generate unique quantized bit patterns that are difficult to replicate, even if the device is opened and analyzed
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
The system significantly increases randomness and security against external attacks, making it difficult to physically replicate the PUF device and providing a strong defense mechanism for user authentication systems.
Implementation Method 1
generating a quantized signal by reading the selected page... providing a reference read voltage to a selected word line coupled to the selected page during a quantization signal generating operation
Data Source
AI summary
The flash memory system according to the embodiment of the present invention is characterized by programming a selected page in a quantization signal generating operation, providing a reference read voltage to a selected word line connected to the selected page, A flash memory for generating a flash memory; And a memory controller for receiving a quantized signal from the flash memory and generating a response using the quantized signal, wherein the memory controller receives an challenge from a host and the flash memory performs the quantized signal generation.