PUF-Based Blockchain Authentication with Reduced Error Rates

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Solution Overview

Problem

Conventional blockchain systems lack secure identification and authentication of users and devices originating transactions, and private keys used for signing blocks can become compromised, risking malicious transactions.

Innovation Solution

The use of physical unclonable function (PUF) generators to enable authentication of client devices and the generation of one-time private/public key pairs for transaction signing, without exchanging information that could compromise security over insecure networks, through an enrollment procedure, handshaking, key generation, blockchain signing, and ledger maintenance stages.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional cryptographic systems use private keys for signing blocks, then transaction authentication is enabled, but security is compromised when private keys are stolen or compromised

Engineering Contradiction:

ImprovesecurityVSAvoidkey compromise risk

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary authentication during an enrollment phase where challenge-response pairs are generated and stored before actual transaction signing. This preliminary action creates a secure binding between the PUF device and the system without requiring the PUF to be present during transactions, thereby preventing key compromise while maintaining authentication reliability

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention creates a cryptographic copy of the PUF's challenge-response behavior through stored enrollment data. Instead of storing the PUF device itself or its private keys, the system stores challenge-response pairs that replicate the authentication function. This copying approach allows secure authentication without exposing the physical PUF device or its internal state to potential compromise

Inventive Principle:

Principle #26Copying

2Reliability

If PUF devices are used for authentication, then security is enhanced, but error rates in challenge-response pairs increase due to physical variability

Engineering Contradiction:

Improveauthentication securityVSAvoidchallenge-response error rate

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The enrollment phase performs preliminary measurements of PUF challenge-response pairs and stores corrected reference values. By pre-characterizing the PUF device's response behavior under various conditions during enrollment, the system compensates for physical variability during actual authentication without requiring real-time error correction, thereby maintaining both security and precision

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system incorporates error tolerance by storing multiple challenge-response pairs and using threshold-based verification. This beforehand cushioning accounts for potential measurement errors by building in a margin of error that allows authentication to succeed even when individual PUF responses vary slightly due to physical variability

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Ease of operation

If private keys are exchanged over networks for blockchain signing, then transaction authentication is enabled, but security is reduced due to exposure over insecure networks

Engineering Contradiction:

Improvetransaction signing capabilityVSAvoidnetwork exposure risk

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The invention extracts the authentication function from the physical PUF device and implements it through stored challenge-response pairs. By taking out the essential authentication capability from the physical device and representing it as data, the system enables network-based transaction signing without exposing the actual PUF device or requiring continuous network connection to the physical hardware, thereby maintaining ease of operation while reducing network exposure risk

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The stored challenge-response pairs serve as an intermediary between the PUF device and the blockchain network. This intermediary allows transaction authentication to occur over insecure networks without directly exposing the PUF device or its private keys to network transmission, thereby enabling ease of operation while mitigating network exposure risks through cryptographic mediation

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS11271759B2Secure digital signatures using physical unclonable function devices with reduced error rates

Publication Date: 2022.03.08 ARIZONA BOARD OF REGENTS ACTING FOR & ON BEHALF OF NORTHERN ARIZONA UNIV

AI summary

Systems and methods for securing blockchain and other cryptographically signed ledgers are disclosed. Client devices with arrays of physical-unclonable-function devices are respond to challenges from a server. Characteristics of the arrays are stored by the server during a secure enrollment process. Subsequently, the server issues challenges to the clients and receives responses generated by the clients from characteristics of portions of the arrays specified by the challenges. The challenge responses are used to authenticate the clients and are also used as cryptographic private keys for signing transaction blocks. Public keys corresponding to the private keys are generated allowing signed transaction blocks to be validated as well as allowing clients originating the transactions to be authenticated by other clients. Ternary PUF characterization schemes are used to achieve acceptable authentication error rates.