Physical Unclonable Function Generator Using CMOS Process Variations
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing security applications in semiconductor devices face vulnerabilities due to high costs and susceptibility to tampering, as they rely on expensive and non-standard manufacturing processes for generating unique, non-duplicable, statistically random numbers used for identification and encryption, which can be visually inspected or intercepted.
Innovation Solution
A number generator system utilizing inherent differences among physical elements, such as capacitors, to generate unique and non-duplicable, statistically random bits through an integrator and comparison-decision logic, amplifying small differences between elements to reliably determine '1' or '0' values, providing a secure and cost-effective solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional solutions (fuses, OTP memory, SRAM) are used to generate unique numbers, then the numbers can be generated and stored, but the cost increases and security vulnerability to tampering occurs
Solution Approach 1:
The patent uses standard CMOS工艺 to create physical elements that are inexpensive to manufacture. The unique numbers are generated from inherent process variations in these elements rather than requiring expensive specialized structures like floating gates or anti-fuses, thereby reducing manufacturing cost while maintaining security.
Solution Approach 2:
The system exploits inherent process variations that naturally occur during standard manufacturing to generate unique numbers. No additional manufacturing steps or specialized structures are required - the randomness is self-generated from the physical elements' natural variations, eliminating the need for expensive post-processing or special manufacturing procedures.
2Reliability
If fuses or OTP memory are used to store unique numbers, then the numbers can be programmed and retained, but they become vulnerable to visual inspection and tampering
Solution Approach 1:
The patent extracts the unique number generation function from traditional storage structures (fuses, OTP memory) and embeds it directly in the physical elements themselves. The unique numbers are not stored in separate accessible memory but are continuously generated from the inherent properties of the physical elements, making them inaccessible for direct inspection or extraction.
Solution Approach 2:
The unique number generation is nested within the standard CMOS circuit structure itself. The physical elements are integrated into the normal circuit fabric, and their inherent variations are exploited to generate unique numbers without requiring separate security structures. This nesting makes the unique numbers difficult to access or tamper with while maintaining standard manufacturing processes.
3Reliability
If SRAM is used to store unique numbers, then the numbers can be retained, but they can be directly coupled out and intercepted during tamper attempts
Solution Approach 1:
Instead of storing unique numbers in accessible SRAM that can be intercepted, the patent generates unique numbers on-the-fly from physical elements with inherent process variations. The numbers are not stored in a vulnerable memory structure but are continuously regenerated from the physical properties of the elements, eliminating the interception vulnerability while using standard CMOS工艺.
4Reliability
If non-standard manufacturing processes are used to enable special structures, then unique numbers can be generated securely, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent exploits inherent process variations that naturally occur during standard CMOS manufacturing to generate unique numbers. No special structures like floating gates or anti-fuses are required, and no non-standard manufacturing processes are needed. The system self-generates unique numbers from the natural variations in physical elements created during normal fabrication, thereby maintaining standard manufacturing processes while achieving secure unique number generation.
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
The system generates stable, repeatable, and statistically random numbers suitable for identification, cryptographic keys, or seeds, enhancing security by being physically uncloneable and resistant to tampering, while reducing costs and chip estate requirements.
Implementation Method 1
The integrator is coupled to the plurality of physical elements, selects two physical elements, and generates an integrated difference signal according to a difference between these two physical elements
Data Source
AI summary
The invention relates to semiconductor devices, and more particularly, to systems, devices and methods of utilizing inherent differences among physical elements in an electrical component to generate unique and non-duplicable numbers that are statistically random and repeatable. These bits may be applied as identifications, random number seeds or encryption keys in many security applications, e.g., a financial terminal. An integrator is coupled to a plurality of physical elements, selects two physical elements or element sets, and generates an integrated difference signal according to a difference between these two physical elements or element sets. A comparison-decision logic further determines whether the difference between the selected two physical elements is associated with a bit of “1” or “0”. In some embodiments, a multi-bit number constitutes multiple bits each of which may be derived from a difference between two randomly selected physical elements or element sets.