MEMS Physical Unclonable Function with Dynamic Control
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Solution Overview
Problem
Conventional physical unclonable functions (PUFs) are limited in generating multiple responses to a challenge, restricting the generation of diverse cryptographic keys, which is a critical issue for secure communication and data encryption, especially in applications like the 'Internet of Things' where multiple identical entities need individualization.
Innovation Solution
Employing a micro-electro-mechanical system (MEMS) as a PUF with a controllable control element that alters the mapping rule by modifying ambient parameters such as temperature and pressure, allowing generation of multiple responses to the same challenge, and enabling reconfiguration or destruction of cryptographic keys.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional PUF is used, then a single response to a challenge is generated, but the ability to generate multiple cryptographic keys is limited
Solution Approach 1:
The patent applies the dynamics principle by making the PUF system adjustable through control elements that can change the mapping rule between challenge and response. The control element modifies physical parameters (such as temperature via heating/cooling elements or pressure) to dynamically alter the PUF's behavior, enabling multiple responses to the same challenge while maintaining a relatively simple base structure.
Solution Approach 2:
The patent implements parameter changes by using control elements that modify physical parameters of the PUF system. Specifically, heating elements change temperature, cooling elements adjust thermal conditions, and pressure elements alter mechanical stress, all of which affect the mapping rule and enable generation of different responses without fundamentally changing the PUF structure.
2Adaptability or versatility
If the mapping rule is altered to generate multiple responses, then cryptographic key diversity increases, but control complexity increases
Solution Approach 1:
The patent applies universality by designing control elements that can serve multiple functions. The same control element structure (heating, cooling, pressure application) can be used across different PUF configurations and operational modes, providing a unified approach to mapping rule alteration rather than requiring separate mechanisms for each function.
Solution Approach 2:
The patent implements self-service through measuring elements that automatically monitor the physical parameters (temperature, pressure) and provide feedback for controlling the mapping rule. This self-measuring and self-regulating capability reduces the need for external complex control systems, as the PUF system partially manages its own configuration.
3Adaptability or versatility
If environmental parameters are used to alter the mapping rule, then response diversity increases, but sensitivity to external conditions increases
Solution Approach 1:
The patent applies feedback by incorporating measuring elements that continuously monitor the physical parameters (temperature, pressure) affecting the PUF. These measurements are fed back to the control unit, which adjusts the control element outputs to compensate for environmental variations, thereby maintaining stable and reliable response generation despite external condition changes.
Solution Approach 2:
The patent uses control elements as intermediaries between the PUF core and the environmental parameters. Rather than allowing direct, uncontrolled exposure to temperature and pressure changes, the control elements mediate these influences in a controlled manner, enabling response diversity while filtering out harmful random variations through the feedback control mechanism.
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 enables the generation of multiple cryptographic keys from different responses, enhancing the value of PUFs by allowing reconfiguration and secure erasure of encrypted information, thereby improving the security and versatility of cryptographic operations.
Implementation Method 1
These mechanical and/or electrical properties are influenced by ambient parameters like, in particular, temperature and pressure, so that these properties and consequently the mapping rule are likewise able to be altered by a selective change of the ambient parameters, especially by a heating element and/or cooling element as control element
Implementation Method 2
These mechanical and/or electrical properties are influenced by ambient parameters like, in particular, temperature and pressure, so that these properties and consequently the mapping rule are likewise able to be altered by a selective change of the ambient parameters, especially by a heating element and/or cooling element as control element
Implementation Method 3
Another advantageous possibility for destroying micro-electro-mechanical systems lies in the use of what are referred to as pull-in effects. In that case, a voltage is applied to adjacent conductive structures (electrodes) which is so high that due to electrostatic attraction, they attract each other and touch, which leads to destruction of the micro-electro-mechanical structure.
Data Source
AI summary
An assembly made up of a micro-electro-mechanical system as physical unclonable function, which in reaction to a challenge, outputs a response in accordance with a mapping rule, and a controllable control element which is equipped, in accordance with a control command, to adjust an ambient parameter influencing the mapping rule.