Electrical System Fingerprinting via Challenge-Response Key Generation
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Solution Overview
Problem
Existing technologies lack a suitable method to identify a system comprising multiple electrical devices based on unique properties of the devices and their connections, as most PUF structures are intrinsic and inaccessible from an external entity.
Innovation Solution
A method involving applying a predefined analogue electrical challenge signal to an electrical system, recording and digitizing the response signal, extracting features using time series classification, and converting them into a cryptographic key for system identification, utilizing manufacturing variances in components and connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple PUFs from different devices in the system are used, then the identification capability of the system is improved, but the accessibility and ease of operation deteriorate because most PUF structures are intrinsic and inaccessible from external entities
Solution Approach 1:
The patent introduces an intermediary approach by using observable electrical characteristics (current consumption, signal timing) as mediators to access the unique fingerprint of the system. Instead of directly accessing intrinsic PUF structures, the system uses these intermediary electrical measurements that can be observed from outside the device, thereby resolving the contradiction between identification accuracy and external accessibility.
2Measurement precision
If PUF structures are implemented in individual devices, then unique device identification is achieved, but system-level identification capability deteriorates as there is no solution based on properties of multiple devices working together
Solution Approach 1:
The patent merges the electrical characteristics of multiple devices and their interconnections into a unified system-level fingerprint. By combining observations from current consumption profiles, signal timing, and other electrical properties across multiple devices, the system creates a composite identifier that represents the entire system rather than individual components, thus achieving system-level identification versatility.
Solution Approach 2:
The patent creates a universal identification method that works across different device types and configurations. The electrical characteristic-based fingerprinting approach is not limited to specific PUF implementations or device architectures, making it universally applicable to various electrical systems while maintaining the ability to identify both individual devices and system-level configurations.
3Measurement precision
If NotchPUF structure is provided on the printed circuit board, then board-level unique identification is achieved, but device complexity and manufacturing requirements worsen due to explicit PUF structure implementation
Solution Approach 1:
The patent extracts the identification capability from explicit PUF structures and embeds it into the normal operational electrical characteristics of the system. Instead of adding specialized NotchPUF structures to the PCB, the method extracts unique fingerprints from existing electrical properties such as current consumption patterns and signal timing, thereby eliminating the need for additional hardware complexity while maintaining identification accuracy.
4Measurement precision
If training data collection is performed for fingerprint generation, then identification accuracy is improved, but loss of time and productivity worsen due to required training period
Solution Approach 1:
The patent implements a self-service approach where the system automatically generates its fingerprint from normal operational data without requiring external training interventions. The electrical characteristics are captured during regular system operation, and the fingerprint generation is performed autonomously using the collected operational data, eliminating the need for separate training periods and allowing immediate identification capability.
Data Source
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AI summary
The invention relates to a method of generating a cryptographic key (34) to identify an electrical system (14), the electrical system (14) comprising electrical devices (16) that are interconnected by electrical connections (18), the method comprising the following steps. Providing a predefined analogue electrical challenge signal (30) to the electrical system (14), for a predefined excitation time; Recording an analogue electrical response signal (32) of the electrical system (14); converting the analogue electrical response signal (32) to a digitized electrical response signal; Extracting predefined and real-valued features of the response time frame of the digitized electrical response signal; Mapping a binary feature vector to a feature set; and generating the cryptographic key (34) associated with the feature set of the electrical system (14).