Challenge Response System Using PUF Decoupling
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Solution Overview
Problem
Conventional challenge/response authentication systems using physically unclonable functions (PUFs) are noisy, produce non-unique responses, require excessive storage for challenge/response pairs, and lack variability, leading to unreliable authentication.
Innovation Solution
A method where a computational device receives a challenge, qualifies and permutes random values to generate a response, using techniques like exclusive OR operations or addition, which can be used as an encryption key, and outputs an encrypted message, decoupling the challenge/response from the PUF, allowing for a large number of unique pairs with reduced storage requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional PUF-based challenge/response systems are used, then authentication is provided, but the responses are noisy and non-unique, reducing reliability
Solution Approach 1:
The system segments the challenge/response process into distinct phases: challenge generation, random value selection based on challenge bits, and response generation. This segmentation allows each phase to be optimized independently, ensuring unique and reliable responses without the noise problems of conventional PUF systems.
Solution Approach 2:
The patent replaces physical PUF structures with software-based random values that are selected and processed computationally. This disposable computational approach eliminates the noise and non-uniqueness issues of physical PUFs while maintaining security through cryptographic processing.
2Reliability
If PUF-based authentication is implemented, then security is provided, but excessive storage is required for challenge/response pairs
Solution Approach 1:
The system uses dynamic random value selection where the challenge bits directly control which random values are selected and how they are processed. This dynamic approach generates unique responses on-demand without requiring pre-stored challenge/response pairs, dramatically reducing storage requirements while maintaining security.
Solution Approach 2:
The computational device generates responses autonomously using its own random values and the challenge input, without requiring external storage of response data. The system serves itself by computing responses dynamically rather than retrieving them from storage.
3Adaptability or versatility
If traditional PUF systems are used, then challenge/response authentication is achieved, but variability is limited, reducing authentication flexibility
Solution Approach 1:
The system changes parameters by using the challenge bits to control multiple aspects of response generation: which random values are selected, how they are combined, and the processing operations applied. This parameter control provides high variability and flexibility while maintaining deterministic and consistent responses for the same challenge.
Data Source
AI summary
A challenge/response system separates a physically unclonable function from the challenge/response. Bits in a challenge are used to qualify random data values. The random data values are permuted to generate a result. The result is used to encrypt a response that is sent in reply to the challenge. Additional permuting mechanisms may be used to further obfuscate the response.