Solid-State Imaging Device Tamper-Resistant Key Generation

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Solution Overview

Problem

Current solid-state imaging devices lack tamper resistance, making it easy for unauthorized users to alter or falsify captured image data, particularly when dealing with personal secrets, and it is difficult to ensure the security of unique keys.

Innovation Solution

A solid-state imaging device with a pixel portion and a reading part that generates a unique key using pixel fluctuation information or reading part fluctuation information, ensuring secure image data by combining this key with the image data for protection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a unique key is used for encryption to ensure confidentiality, then image security is improved, but the key becomes vulnerable to analysis and compromise

Engineering Contradiction:

Improveimage securityVSAvoidkey tamper resistance

Core Design Contradiction:

ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The system uses the imaging device's own inherent characteristics (pixel fluctuations, circuit variations, manufacturing differences) to generate the encryption key, eliminating the need for external key management. The device serves itself by converting its natural physical variations into a secure key source, making the key inherently tied to the device's identity and difficult to compromise through external analysis

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system transforms physical parameters (pixel response variations, circuit electrical characteristics, manufacturing tolerances) into cryptographic parameters (encryption keys). By changing the domain from physical measurements to cryptographic values, the system achieves both security and tamper resistance simultaneously

Inventive Principle:

Principle #35Parameter changes

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 provides enhanced tamper resistance, preventing unauthorized alteration and falsification of images by using unique keys generated from device-specific fluctuations, ensuring secure image data integrity.

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

PatentUS10382708B2Solid-state imaging device, method for driving solid-state imaging device, and electronic apparatus with physically unclonable function

Publication Date: 2019.08.13 THE RITSUMEIKAN TRUST

AI summary

A solid-state imaging device 10 includes a pixel portion 20 in which a plurality of pixels including photodiodes are arranged in rows and columns, a reading part 90 for reading pixel signals from the pixel portion, and a key generation part 82 which generates a unique key by using at least one of pixel fluctuation information or reading part fluctuation information. According to this configuration, the tamper resistance of the unique key can be secured and consequently alteration and falsification of images can be prevented.