PUF Cell Array Circuit for Random Authentication Key Generation
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Solution Overview
Problem
Existing PUF circuits face challenges in efficiently generating unique authentication information while minimizing area occupancy and maintaining randomness, especially due to process errors and variations in transistor physical characteristics.
Innovation Solution
A PUF circuit design that includes two arrays of PUF cells with a controller to select and generate unique information based on output voltages from the cells, using a differential amplifier, chopper, and low band pass filter to amplify and clean the voltage differences, thereby reducing area usage and maintaining randomness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional PUF circuits are used to generate unique authentication information, then security and randomness are achieved, but area occupancy increases and cost efficiency decreases
Solution Approach 1:
The PUF circuit is segmented into multiple independent arrays, each containing multiple PUF cells. The controller selectively activates specific cells from different arrays to generate authentication information, allowing the system to achieve the required security level with a smaller total circuit area by using only a subset of available cells.
Solution Approach 2:
Instead of utilizing all PUF cells in the circuit for every authentication operation, the controller selectively activates only the necessary number of cells required to generate the authentication information. This partial action approach reduces the effective area occupancy while maintaining the security requirements.
2Reliability
If process errors and transistor variations are exploited for uniqueness, then authentication security is improved, but measurement precision deteriorates due to voltage differences
Solution Approach 1:
The controller implements a feedback mechanism that reads the output voltages from selected PUF cells and uses this information to determine the authentication result. The controller can perform multiple readings and use majority voting or threshold-based decision making to overcome noise and variations, thereby maintaining measurement precision while exploiting process errors for uniqueness.
Solution Approach 2:
The PUF cells inherently generate their own unique characteristics through unavoidable process variations and transistor mismatches. The system exploits these self-generated variations without requiring external calibration or adjustment, allowing the circuit to automatically produce unique authentication information while the controller handles the precision requirements through selective cell activation.
Data Source
AI summary
The present disclosure provides a PUF circuit including a first array including at least one physically unclonable function (PUF) cell, a second array including at least one PUF cell, and a controller which selects a first PUF cell from the first array and selects a second PUF cell from the second array and generates unique information represented by the first PUF cell and the second PUF cell based on a first output voltage output by the first PUF cell and a second output voltage output by the second PUF cell.