PUF Key Generation for Lightweight IoT Encrypted Communication

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Solution Overview

Problem

Existing cryptographic protocols for Internet of Things devices require bulky hardware, significant computation, and high resource consumption, and are vulnerable to data breaches due to storage of encryption information.

Innovation Solution

A cryptographic communication method utilizing a physically unclonable function (PUF) circuit to generate private keys and session keys on demand, enabling lightweight hardware, low computation, and secure encryption without storing sensitive information.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional cryptographic protocols are used for data transmission, then data confidentiality and authentication are ensured, but hardware size and resource consumption increase significantly

Engineering Contradiction:
Improvedata confidentialityVSAvoidhardware size
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the essential cryptographic function (key generation) from traditional bulky cryptographic hardware and implements it using a PUF circuit that leverages inherent physical variations in semiconductor structures. This extraction allows maintaining security while dramatically reducing hardware footprint by eliminating the need for large cryptographic processing units and key storage memory.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces traditional mechanical/electronic cryptographic systems with a physics-based PUF system that uses inherent physical variations in semiconductor materials and structures. The PUF circuit generates cryptographic keys based on physical properties rather than complex computational algorithms, reducing hardware complexity while maintaining security.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If traditional cryptographic protocols are used for data transmission, then data authentication is ensured, but computation requirements and resource consumption increase

Engineering Contradiction:
Improvedata authenticationVSAvoidresource consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The PUF circuit performs self-authentication by generating unique cryptographic responses based on its inherent physical characteristics. Each PUF circuit is inherently unique due to manufacturing variations, and this uniqueness is automatically exploited for authentication without requiring external verification infrastructure or complex computational validation, reducing overall system resource consumption.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The PUF circuit pre-generates cryptographic keys and authentication credentials during device manufacturing based on its physical structure. This preliminary action eliminates the need for complex key generation and management operations during runtime, reducing computation requirements and energy consumption during actual data transmission and authentication processes.

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If encryption information is stored in memory for later use, then cryptographic operations can be performed, but security vulnerability increases when devices are stolen

Engineering Contradiction:
Improvecryptographic operation capabilityVSAvoidsecurity vulnerability
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The PUF circuit generates cryptographic keys on-demand by reading its physical structure characteristics rather than retrieving stored keys. Each cryptographic operation triggers fresh key generation based on the PUF's physical state, effectively discarding previous keys and preventing their reuse or extraction. This approach maintains cryptographic operation capability while eliminating security vulnerabilities associated with key storage.

Inventive Principle:
Principle #34Discarding and recovering

Solution Approach 2:

The patent treats cryptographic keys as temporary, disposable objects that are generated and consumed in each cryptographic session. The PUF circuit continuously generates new keys based on its physical characteristics, and these keys have short lifetimes, preventing attackers from benefiting even if they manage to extract or steal the device, as the keys would have already changed.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Data Source

PatentEP4704369A1Physical unclonable function-based encrypted communication method and computing device for performing the same
Publication Date: 2026.03.04 CHUNGBUK NAT UNIV IND ACADEMIC COOP FOUNDATION
  • EP4704369A1 patent drawingFigure 1A
  • EP4704369A1 patent drawingFigure 1B
  • EP4704369A1 patent drawingFigure 2

AI summary

The electronic device according to one example disclosed, comprises a PUF circuit which inputs a random challenge signal into a physically unclonable function to generate a private key; a communication device which receives an encrypted message by a temporarily generated message session key, and an encrypted message session key generated by encrypting the message session key with a public key corresponding to the private key, from a counterpart electronic device; and a controller which obtains the message session key by decrypting the encrypted message session key with the private key, and decrypts the encrypted message with the message session key.