Tamper Detector Hardware Random Seed LFSR
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Solution Overview
Problem
Sophisticated attacks can neutralize the tamper detection capability of secured electronic modules by predicting pseudorandom coded signals generated by linear feedback shift registers (LFSR) if the generator polynomial and initial seed values are known.
Innovation Solution
Implementing a hardware-based random number generator to generate and load initial random seed values directly into the LFSR, ensuring they are not software visible, thereby making it difficult for attackers to predict the pseudorandom coded detection signals even if they are aware of the LFSR implementation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If software-based random number generation is used to seed the LFSR, then the system is easier to implement and control, but the random seed values become predictable and visible to attackers who know the software implementation
Solution Approach 1:
The patent replaces software-based random number generation with a hardware-based random number generator. This substitution moves the random number generation from the software domain to the hardware domain, making the seed values unpredictable and invisible to software-based attacks while maintaining ease of implementation through dedicated hardware circuitry.
2Ease of operation
If the generator polynomial and initial seed values are made visible to software, then the system is easier to control and monitor, but attackers can predict the pseudorandom coded detection signals
Solution Approach 1:
The patent introduces a hardware-based random number generator as an intermediary between the control system and the LFSR. This intermediary generates and loads random seed values directly into the LFSR without making them visible to software, thereby maintaining control capability while preventing prediction of the pseudorandom coded detection signals.
3Reliability
If a hardware-based random number generator is used to generate and load initial random seed values directly into the LFSR, then the security against prediction is enhanced, but the device complexity increases
Solution Approach 1:
The hardware-based random number generator operates autonomously to generate and load random seed values directly into the LFSR without requiring software intervention. This self-service capability enhances security by eliminating the software attack surface while the integrated nature of the hardware generator minimizes the increase in device complexity.
Data Source
AI summary
A system includes a tamper detector that includes a linear feedback shift register (LFSR) for generating pseudorandom coded detection signals as a function of seed values and a generator polynomial. The generator polynomial is loaded from a controller to the LFSR via software, and the seed values are directly loaded from a hardware-based random number generator to the LFSR. The tamper detector has output and input elements for connection to ends of a tamper detection circuit, wherein the detection circuit is linked with a physical closure surrounding an electronic circuit. The detection signals are applied to the output element and incoming signals are received from the tamper detection circuit at a comparator via the input element. Comparison of the incoming signals with the coded detection signals is performed to detect interference with the detection circuit in an attempt to tamper with the electronic circuit.