Non-leaky Helper Data for Noisy PUF Key Extraction
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Solution Overview
Problem
Counterfeit electronic components can compromise device security due to noise-induced key mismatches during Physically Unclonable Function (PUF) authentication, as conventional error correction schemes leak information about the PUF, potentially revealing the cryptographic key.
Innovation Solution
A method involving generating and reproducing cryptographic keys using non-leaky helper data from NAND flash memory arrays, where the helper data does not reveal information about the key, and applying error correction codes to refine the key estimates, ensuring secure authentication without compromising the PUF's integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional error correction schemes are used to correct noise-induced key mismatches, then authentication reliability is improved, but information about the PUF is leaked, compromising security
Solution Approach 1:
The patent introduces helper data as an intermediary that enables error correction without directly revealing PUF information. The helper data is processed through a reconciliation mechanism that corrects noise-induced mismatches while maintaining PUF security, effectively mediating between the need for reliable authentication and the requirement to prevent information leakage.
Solution Approach 2:
The patent transforms the PUF response from its original noisy form into a corrected key by applying parameter changes through the helper data reconciliation process. This transformation allows the system to operate in a parameter space where noise is corrected without exposing the underlying PUF characteristics, thereby resolving the contradiction between reliability and security.
2Speed
If digital identifiers are stored in memory for authentication, then authentication speed is improved, but the identifiers can be read using optical methods, compromising security
Solution Approach 1:
The patent extracts the authentication functionality from stored digital identifiers and relocates it to the PUF itself. By taking out the need for stored keys and making the PUF response the direct authentication credential, the system achieves fast authentication without the security vulnerability of stored identifiers that can be optically read.
Solution Approach 2:
The patent creates a functional copy of the authentication mechanism by using the PUF response directly as the credential. Instead of copying keys to memory for fast access, the system uses the PUF's inherent response generation capability as the authentication source, eliminating the need for stored copies while maintaining speed.
3Device complexity
If PUF responses are digitized directly from noisy analog measurements, then device complexity is reduced, but noise causes key mismatches, reducing authentication reliability
Solution Approach 1:
The patent applies preliminary action by pre-processing the noisy PUF response through helper data generation and reconciliation before final authentication. This preliminary processing step corrects potential noise-induced errors in advance, ensuring reliable authentication without requiring complex real-time correction mechanisms that would increase device complexity.
Data Source
AI summary
A method generating a cryptographic key and corresponding helper data includes measuring an analog value associated with a physical property of cells of a memory array; digitizing the measured analog value to generate the cryptographic key; quantizing the measured analog value to generate the corresponding non-leaky helper data.