PUF Signature Module Classification With Weak-Bit Masking

The patent applies preliminary action by characterizing PUF cells under controlled test conditions before final deployment. A test mode is enabled that applies multiple stress conditions (temperature, voltage, timing variations) to characterize each cell's behavior. This preliminary characterization allows the system to identify and exclude unreliable cells before they are used for security-critical operations, thereby resolving the contradiction between using PUF cells for security and their unreliable behavior under stress.

The patent implements feedback mechanisms where the characterized PUF cell data is fed back into the system to generate a mask that identifies unreliable cells. This mask is then used to exclude problematic cells from future security operations. The feedback loop continuously monitors PUF cell performance and adjusts the mask accordingly, ensuring that only reliable cells are used for encryption and identification, thus maintaining security while accounting for manufacturing variances and operational stress.

The patent applies the extraction principle by separating reliable PUF cells from unreliable ones through characterization and masking. The system extracts only the trustworthy cells that pass reliability testing and excludes the problematic ones from the final identifier generation. This allows the system to maximize identification capability using the largest possible set of cells while maintaining security by removing only the minimal number of unreliable cells, thus resolving the contradiction between productivity and reliability.

The patent implements local quality by applying different treatment to different PUF cells based on their individual reliability characteristics. Rather than treating all cells uniformly, the system characterizes each cell's response to stress conditions and applies a customized mask to exclude only the unreliable cells. This localized approach allows maximum utilization of reliable cells for identification while maintaining security, resolving the contradiction between maximizing identification capability and ensuring security assurance.

The patent applies universality by designing a single test mode that can evaluate PUF cells under multiple stress conditions simultaneously. The test mode is configured to apply temperature variations, voltage changes, and timing variations in an integrated manner, allowing one test framework to assess reliability across multiple dimensions. This multi-functional approach improves reliability through comprehensive stress testing while avoiding the complexity of separate testing procedures for each condition, thus resolving the contradiction between reliability improvement and testing complexity.

The patent implements parameter changes by systematically varying test parameters (temperature, voltage, timing) to characterize PUF cell behavior under different stress conditions. The test mode modifies these parameters in controlled sequences to elicit reliable characterization data. By using parameter changes in a structured manner, the system achieves comprehensive reliability assessment without requiring proportionally complex testing infrastructure, thus resolving the contradiction between improving reliability through stress testing and managing testing complexity.