PUF Authentication Without Error Correction Codes
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Solution Overview
Problem
Conventional physical unclonable function (PUF) authentication systems are sensitive to aging and noise, requiring error correction codes that are costly and impractical for certain devices, and are vulnerable to security threats due to storage of PUF values.
Innovation Solution
The use of analog PUF signals digitized to higher resolution, distance-based authentication without error correction codes, and the application of garbled circuits to securely compute authentication values without revealing new PUF values, along with generating cryptographic keys from stable PUF outputs to enhance security.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If error correction codes are applied to PUF values, then authentication reliability is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts only the essential authentication function from PUF values without applying error correction codes. By removing the error correction component, the system achieves authentication with reduced device complexity while maintaining reliability through the inherent stability of PUF characteristics.
Solution Approach 2:
The patent uses simple, low-cost PUF values directly for authentication without expensive error correction mechanisms. The system accepts that PUF values may have minor variations over time but uses threshold-based comparison to maintain authentication reliability without additional complexity.
2Ease of operation
If PUF values are stored for authentication, then authentication functionality is enabled, but security vulnerability increases
Solution Approach 1:
The patent performs preliminary enrollment where PUF values are measured and stored during device manufacturing or initial setup. This preliminary action enables subsequent authentication operations to proceed efficiently by comparing new PUF measurements against the stored enrollment values without requiring real-time complex computations.
Solution Approach 2:
The patent introduces threshold-based comparison as an intermediary mechanism between stored PUF values and authentication decisions. This intermediary layer provides security by not requiring exact matches and by using distance metrics that tolerate natural PUF variations while preventing unauthorized access.
3Measurement precision
If high-resolution digitization of analog PUF signals is applied, then measurement precision is improved, but quantization errors increase
Solution Approach 1:
The patent changes the parameter of digitization resolution to an optimal level that balances measurement precision with quantization error. By using sufficient but not excessive bit depth for digitizing analog PUF signals, the system captures enough detail for reliable authentication while minimizing quantization errors that would arise from overly aggressive compression.
Solution Approach 2:
The patent applies partial digitization of the analog PUF signal, capturing only the essential information needed for authentication. Rather than fully digitizing all aspects of the analog signal, the system uses threshold-based comparison and distance metrics that work effectively with partially digitized data, reducing quantization errors while maintaining authentication reliability.
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
This approach reduces quantization errors, extends the useful life of devices by compensating for aging, and enhances security by preventing unauthorized access and data theft, while eliminating the need for costly error correction codes.
Implementation Method 1
A physical unclonable function (PUF) includes circuitry configured to generate an output whose value depends on unique physical properties of the circuitry
Implementation Method 2
an analog-to-digital converter configured to digitize the analog signal to produce a digital PUF value
Data Source
AI summary
This application describes systems and methods for using a physical unclonable function (PUF) to authenticate a device, which may include circuitry for generating PUF values that may uniquely identify the device. According to one aspect, the device may provide enrollment PUF values to an authentication device. The device may later be authenticated if PUF values generated by the device are within a threshold distance of the enrollment PUF values. Since the PUF values are compared using a distance, it may not necessary to apply an error correcting code to the PUF values. The enrollment values and/or the calculated distance may be adjusted to compensate for time variations in the PUF values due to circuit aging. Systems and methods are also described herein for authenticating the device without revealing new PUF values to any second party, for example using a cryptographic technique known as a garbled circuit.