Non-Volatile Memory PUF Using Access Transistor Variations
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Solution Overview
Problem
Current semiconductor memory solutions lack sufficient security measures to prevent unauthorized access and cloning, particularly in non-volatile memory chips used for secure applications like banking cards and pay TV, as existing physical unclonable functions (PUFs) are either not robust enough or require additional memory blocks and complex logic, making them vulnerable to attacks.
Innovation Solution
A non-volatile memory design that utilizes the natural variation in electrical characteristics of access transistors, specifically their threshold voltages, as a physical unclonable function (PUF), which is measured and processed to generate die-individual encryption keys, enhancing security without the need for extra memory blocks or complex logic, by leveraging the inherent mismatch in access transistors within the memory array.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional memory blocks and complex logic are used to implement physical unclonable functions, then security robustness is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent utilizes the inherent manufacturing variations of existing access transistors to generate unique identification codes, eliminating the need for additional security hardware. The access transistors themselves serve dual purposes: normal memory access operations and generating unclonable identification through their natural electrical characteristic variations.
Solution Approach 2:
The invention extracts the identification function from separate security modules and integrates it into the existing access transistor structure. By measuring the natural variations in threshold voltage of access transistors that already exist in the memory array, the system obtains unique identifiers without adding dedicated security blocks.
2Reliability
If additional memory blocks and complex logic are used to implement physical unclonable functions, then security robustness is improved, but manufacturing cost increases
Solution Approach 1:
The access transistors are designed to perform multiple functions: standard memory access operations and generation of unclonable identification codes. This multi-functionality eliminates the need for separate security hardware, reducing overall device complexity and manufacturing cost while maintaining security robustness.
3Device complexity
If natural variation in access transistor characteristics is used as PUF, then device complexity is reduced, but measurement precision requirements increase
Solution Approach 1:
The patent replaces complex security measurement systems with simplified electrical characteristic measurements of access transistors. By measuring threshold voltage variations through standard transistor operation, the system obtains precise unique identifiers without requiring sophisticated measurement apparatus.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach increases the security level of semiconductor memory at a lower cost and complexity by using existing memory structures, providing unique, random encryption keys for each die without relying on external storage, thus preventing cloning and unauthorized access.
Implementation Method 1
a measurement unit, wherein said measurement unit is configured to measure a variation between electrical characteristics of said access transistors
Data Source
AI summary
In accordance with a first aspect of the present disclosure, a non-volatile memory is provided, comprising: a plurality of storage elements; a plurality of access transistors, said access transistors being connected to one or more of said storage elements; a measurement unit, wherein said measurement unit is configured to measure a variation between electrical characteristics of said access transistors; a processing unit configured to use said variation between electric characteristics as a physical unclonable function. In accordance with a second aspect of the present disclosure, a corresponding method of manufacturing a non-volatile memory is conceived.