Physically Unclonable Function Authentication Using Correctness Indicators
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Solution Overview
Problem
Physically unclonable function (PUF) circuits face challenges in maintaining consistency over time due to aging, leading to potential authentication failures, and the use of error-correcting codes can reveal sensitive information and create storage issues.
Innovation Solution
Generating multiple PUF values and using the most frequently occurring ones to encrypt and decrypt data, eliminating the need for error-correcting codes by combining them with correctness indicators, and varying environmental conditions to select appropriate PUF values for encryption and decryption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If helper data in the form of an error-correcting code is used to correct generated PUF values, then the PUF circuit reliability is improved, but information about the PUF value is revealed and storage requirements increase
Solution Approach 1:
The patent extracts only the necessary correctness information from the PUF value and stores it separately as a correctness indicator, rather than storing or transmitting the entire PUF value. This allows error correction without revealing the full PUF secret, resolving the contradiction between reliability and information leakage.
Solution Approach 2:
The patent introduces an intermediary correctness indicator that mediates between the PUF value and the error correction process. This indicator serves as a proxy that enables verification and correction without exposing the actual PUF value, thus maintaining security while improving reliability.
2Reliability
If helper data in the form of an error-correcting code is used to correct generated PUF values, then the PUF circuit reliability is improved, but storage requirements increase
Solution Approach 1:
The patent extracts only the essential correctness information from the PUF value and stores it separately as a correctness indicator. This extraction approach reduces the storage burden compared to storing full error-correcting codes while still enabling reliability improvement through verification.
3Stability of the object's composition
If multiple PUF values are generated and the most frequently occurring ones are selected for encryption, then the impact of device aging is minimized, but the complexity of the authentication process increases
Solution Approach 1:
The patent performs preliminary generation and selection of PUF values during the authentication process, using frequency analysis to identify the most stable values. This preliminary action allows the system to adapt to device aging while maintaining a manageable authentication process through systematic selection criteria.
Solution Approach 2:
The patent changes the parameter selection criteria by using frequency occurrence as a metric for selecting PUF values. This parameter-based approach enables the system to dynamically adapt to device aging effects while keeping the authentication process structured and manageable.
Data Source
AI summary
Approaches for using a physically unclonable function (PUF) as a key-encrypting key are disclosed. Data is encrypted using a session key, and at least one PUF value is generated from a PUF. The session key and a correctness indicator are encrypted into a corresponding session key pair using the PUF value. Each session key pair is added to the encrypted data. Subsequent decryption, using a subsequently generated PUF value, of the correctness indicator to an expected value indicates a valid decryption. Decryption may be repeated using a different PUF value if the correctness indicator does not match the expected value. In another approach, the session key may be omitted and the payload data may be encrypted with the different PUF values and paired with correctness indicators.