Solid-State Imaging Device Unique Key Generation via Fluctuation Data

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Solution Overview

Problem

Current solid-state imaging devices face challenges in generating a unique key with high confidentiality and reproducibility, and securing tamper resistance, as existing methods are vulnerable to key reproduction and forgery.

Innovation Solution

A solid-state imaging device with a pixel portion and reading part that generates a unique key using fluctuation information of pixels and readout circuits, enhanced through tamper resistance processing to make the key difficult to break, incorporating decorrelation processing and fuzzy extractors for improved security.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If a unique key is generated using fluctuation information of pixels and readout circuits, then key uniqueness and confidentiality are improved, but key reproducibility and tamper resistance deteriorate

Engineering Contradiction:

Improvekey confidentialityVSAvoidkey reproducibility

Core Design Contradiction:

Loss of informationVSReliability

Solution Approach 1:

The patent introduces an intermediary processing system that includes decorrelation processing and fuzzy extractor processing. These intermediaries transform the raw fluctuation information into a reliable unique key while maintaining confidentiality. The decorrelation processing removes correlations between pixels, and the fuzzy extractor extracts reliable information from the decorrelated data, serving as mediators between the raw fluctuation information and the final unique key.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces direct use of physical fluctuation information with a processed information system. Instead of directly using pixel fluctuation data as the key, the system substitutes a multi-stage processing mechanism (decorrelation + fuzzy extractor) that transforms the physical fluctuations into a more reliable digital key representation, improving reproducibility while maintaining uniqueness.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of manufacture

If existing key generation methods are used, then key generation is simple, but tamper resistance and security against forgery deteriorate

Engineering Contradiction:

Improvekey generation simplicityVSAvoidtamper resistance

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent segments the key generation process into distinct functional modules: fluctuation information acquisition, decorrelation processing, and fuzzy extractor processing. This segmentation allows each module to perform its specific function efficiently while maintaining overall system simplicity. The modular structure makes the system easier to manufacture and implement while providing enhanced security through the combined effect of multiple processing stages.

Inventive Principle:

Principle #1Segmentation

3Reliability

If decorrelation processing and fuzzy extractors are added, then tamper resistance and key security are improved, but device complexity increases

Engineering Contradiction:

Improvetamper resistanceVSAvoidprocessing structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements universal processing blocks (decorrelation processing and fuzzy extractor) that can be applied to various types of fluctuation information from different pixel configurations and readout circuits. These multi-functional blocks handle diverse input data formats and produce consistent unique key output, reducing the need for device-specific customization and thereby limiting the increase in overall device complexity.

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

The solution effectively generates a unique key with high confidentiality and tamper resistance, reliably preventing unauthorized use and forgery of images by enhancing key reproducibility and uniqueness.

Implementation Method 1

CMOS (complementary metal oxide semiconductor) image sensors have been put into practical use. A CMOS image sensor has a floating diffusion (FD) amplifier having, for each pixel, a photodiode (photoelectric conversion element)

Methodology Applied

Scientific EffectPhotoelectric conversion: Photoelectric Effect

Data Source

PatentUS10484638B2Solid-state imaging device, method for driving solid-state imaging device, and electronic apparatus for preventing tampering of an image

Publication Date: 2019.11.19 BRILLNICS JAPAN

AI summary

A solid-state imaging device having a pixel portion in which a plurality of pixels each including a photodiode are arranged in rows and columns, a reading part for reading pixel signals from the pixel portion, and a key generation part which generates a unique key by using, as the key generation-use data, at least one of fluctuation information of pixels and fluctuation information of the reading part, wherein the key generation part includes a tamper resistance enhancement processing part for processing the key generation-use data to enhance the tamper resistance making it difficult to break the unique key as tamper resistance enhancement processing. Due to this, it is possible to generate a unique key having a high confidentiality. Further, it is possible to improve reproducibility and uniqueness of the unique ID, is possible to secure a high tamper resistance of the unique key, and consequently is possible to reliably prevent tampering and forgery of an image.