PUF Information Encryption for Secure External Access

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Solution Overview

Problem

Current technologies lack effective methods to securely synchronize and protect Physically Unclonable Function (PUF) information between devices and servers, making them vulnerable to unauthorized access during communication.

Innovation Solution

A circuit and method that utilize a PUF generator, asymmetric encryption, and helper data to securely transmit PUF responses, where the PUF response is encrypted with a public key and decrypted by an authorized server using a private key, preventing unauthorized access.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If PUF information is transmitted through a communication channel for synchronization, then the device can establish secure communication with the server, but unauthorized servers can intercept and obtain the PUF information during transmission

Engineering Contradiction:

Improvesecure communication establishmentVSAvoidunauthorized access to PUF information

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an intermediary encryption mechanism (public-key cryptography) between the PUF information and the communication channel. The PUF response is encrypted using the server's public key before transmission, and only the authorized server with the corresponding private key can decrypt it. This intermediary layer prevents unauthorized servers from intercepting and using the PUF information directly from the communication channel.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies preliminary anti-action by encrypting the PUF information before transmission through the communication channel. By pre-encrypting the PUF response with the server's public key, the system prevents potential unauthorized access in advance, making the intercepted data useless to unauthorized servers without the corresponding private key.

Inventive Principle:

Principle #9Preliminary anti-action

2Object-affected harmful factors

If the PUF response is encrypted using asymmetric encryption, then unauthorized servers cannot decrypt the PUF information, but the communication protocol becomes more complex

Engineering Contradiction:

Improveunauthorized access preventionVSAvoidcommunication protocol complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent uses public-key cryptography where the public key is a copy of the private key's mathematical counterpart that can be freely distributed. The server has a key pair (public key and private key), and the public key is made available to all devices. This copying mechanism allows secure encryption without requiring complex shared secret establishment protocols, simplifying the overall system while maintaining strong security.

Inventive Principle:

Principle #26Copying

3Ease of operation

If the PUF information is synchronized through a public channel, then the device can authenticate with the server, but the channel is vulnerable to impersonation attacks

Engineering Contradiction:

Improveauthentication capabilityVSAvoidchannel security against impersonation

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent introduces asymmetric encryption as an intermediary layer between the PUF information and the communication channel. The PUF response is encrypted using the server's public key before transmission, and only the authorized server with the corresponding private key can decrypt it. This intermediary layer prevents unauthorized servers from intercepting and using the PUF information directly from the communication channel.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

Inventive Principle:

Principle #9Preliminary anti-action

Data Source

PatentUS11170115B2Method and apparatus for secure external access of the PUF information to an authorized entity

Publication Date: 2021.11.09 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

Disclosed is a device and method to secure PUF information for authorized entities. In one embodiment, a device for securing physically unclonable function (PUF) information includes: a PUF information generator, comprising a PUF cell array and a helper data generator, configured to generate the PUF information, wherein the PUF information comprises a PUF response and helper data; and a PUF information encrypter, comprising a memory unit and a first crypto-system, configured to store at least one public key and encrypt the PUF information from the PUF information generator using one of the at least one public key.