PUF-Based Memory Key Recovery Under Circuit Aging
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Solution Overview
Problem
Existing memory systems using physical unclonable functions (PUFs) face challenges due to the aging of circuit elements, which narrows the error correction capability and increases the amount of auxiliary data required, compromising data confidentiality.
Innovation Solution
The memory system incorporates a fuzzy extractor with a secure sketch that generates auxiliary data and aging information to correct errors caused by circuit element aging, maintaining error correction capability and reducing the amount of auxiliary data needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PUF is used for data encryption, then data security is improved, but aging of circuit elements reduces error correction capability
Solution Approach 1:
The system performs preliminary characterization of the PUF circuit at multiple temperature points before actual use. By pre-measuring the output characteristics across temperature ranges and storing reference data, the system prepares correction information in advance, enabling it to compensate for temperature-induced variations and aging effects during operation without requiring real-time recalibration.
Solution Approach 2:
The system actively varies temperature parameters during PUF characterization to understand and compensate for environmental effects. By measuring PUF output at different temperatures and establishing correction models, the system can adjust its operation to maintain consistent error correction capability despite temperature fluctuations and aging-related parameter drift.
2Reliability
If PUF is used for data encryption, then data security is improved, but the amount of auxiliary data increases
Solution Approach 1:
Instead of correcting all possible PUF output variations, the system focuses on correcting only the most significant error sources identified through temperature-based characterization. By prioritizing correction of dominant error patterns rather than attempting to address every possible variation, the system reduces auxiliary data requirements while maintaining adequate error correction capability for security applications.
Solution Approach 2:
The system uses temperature as a controlling parameter to characterize and correct PUF behavior. By establishing correction models based on temperature-dependent error patterns, the system can predict and correct aging-related variations without requiring extensive auxiliary data, as the temperature parameter provides a compact basis for error correction.
3Reliability
If error correction capability is increased to compensate for aging, then reliability is improved, but the complexity of the system increases
Solution Approach 1:
The system performs comprehensive PUF characterization at multiple temperatures during an initial setup phase, storing reference data and establishing correction models in advance. This preliminary action creates a lookup table or correction database that can be efficiently queried during operation, avoiding the need for complex real-time calculations and reducing operational system complexity while maintaining high error correction capability.
Solution Approach 2:
The system uses its own temperature sensors and characterization data to automatically correct PUF output variations without requiring external calibration equipment or complex intervention. By leveraging internally available temperature information and pre-stored correction models, the system self-corrects for aging and environmental effects, reducing the need for additional complex correction hardware or software.
Data Source
AI summary
According to one embodiment, a memory system includes a nonvolatile memory and a controller. The controller includes a circuit element. At a first timing, the controller acquires first identification information from a characteristic of the circuit element. The controller generates, using the first identification information, an encryption key for data to be written to the nonvolatile memory. The controller acquires aging information of the first identification information. The controller generates, using the aging information, auxiliary data for correcting an error included in second identification information, which is acquired from the characteristic of the circuit element at a second timing, to restore the first identification information.