PUF-Based Security Token for Secure IoT Temperature Sensing
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Solution Overview
Problem
Current temperature sensing technologies in IoT applications are vulnerable to security attacks and falsification, as they can be easily substituted or modified, lacking robust authentication and secure key generation mechanisms.
Innovation Solution
A PUF-based security token that integrates temperature sensing and cryptographic key generation using resistors with unique physical properties, ensuring that any attempt to modify the resistors results in a failure of the temperature sensor/PUF, thereby providing a secure and unclonable identity for authentication and encryption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional temperature sensing technologies are used in IoT applications, then temperature measurement can be achieved, but the system is vulnerable to security attacks and falsification
Solution Approach 1:
The patent combines temperature sensing functionality with PUF-based cryptographic key generation into a single integrated system. The same physical resistors serve dual purposes: measuring temperature and generating unique cryptographic identifiers. This merging ensures that any attempt to tamper with the temperature sensor simultaneously destroys the PUF structure, making falsification detectable and preventing substitution attacks.
Solution Approach 2:
The system uses a composite approach by integrating analog temperature sensing circuits with digital PUF structures based on resistor networks. The resistors form both the temperature sensing element and the physical unclonable function structure, creating a hybrid system that provides both measurement capability and cryptographic security in a unified architecture.
2Adaptability or versatility
If separate temperature sensor and PUF structures are used, then temperature sensing and key generation can be performed, but the device complexity increases
Solution Approach 1:
The patent implements universality by designing the resistor network to perform multiple functions simultaneously. The same physical resistors are used for both temperature measurement (analog function) and cryptographic key generation (digital function). This multi-functionality eliminates the need for separate sensor and PUF structures, reducing device complexity while maintaining dual adaptability.
Solution Approach 2:
The temperature sensing circuit and PUF structure are merged into a single integrated system where the resistor network serves both purposes. The analog-to-digital converter processes the temperature signal while the same resistors form the PUF challenge-response structure, creating a unified device that reduces component count and structural complexity.
3Reliability
If resistors are made tamper-proof, then security is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent converts the natural manufacturing variations and tolerances of resistors, which are typically seen as defects requiring tight control, into the foundation of security. The unique resistance values resulting from normal manufacturing variations create distinct cryptographic fingerprints for each device. Rather than requiring precise control, the system embraces these variations as the source of unclonable identifiers, turning a potential weakness into a security strength.
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 solution offers a stable, affordable, and secure temperature-sensing mechanism that generates unique cryptographic keys resistant to cloning and spoofing, enhancing the security of IoT devices and preventing counterfeiting by ensuring that only genuine products can produce the correct cryptographic key.
Implementation Method 1
analog-to-digital converter having an input connected to the second side of the first resistor wherein an output of said analog to digital converter is related to temperature by a temperature coefficient of resistivity of the first resistor
Data Source
AI summary
Any electrical component that is responsive to a physical or environmental phenomenon may be used to create a secure sensor. A secure sensor may include a first electrical component having a first side connected to a voltage source, a second component having a first side connected to the voltage source, an analog comparator having a first input connected to a second side of the first component and a second input connected to a second side of the second component and an output that represents at least one bit of a key, and an analog to digital converter having an input connected to the second side of the first component wherein an output of said analog to digital converter is related to a physical phenomenon that the component responds to by a coefficient of the components characteristic. The first component and the second component may have the same nominal value. The first component, the second component and the analog to digital comparator may be encased in the same package. The package may be configured to inhibit inspection and discovery of components contained in said package. A processor may be connected to a key register and to a table containing the information related to the sensed physical phenomenon wherein the processor may be configured to store the key bits in the key register and is configured to store data corresponding to the sensed physical phenomenon. The processor may be configured to store a time stamp associated with an entry in the table. A communications interface may be connected to the processor.