Dual Random Bit Generators for IC Anti-Tamper Mesh Detection
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Solution Overview
Problem
Current anti-tamper systems for electronic hardware, such as integrated circuits, face challenges in effectively detecting and responding to unauthorized activities like etching or disabling of mesh wires, which can compromise the security and integrity of the IC chip.
Innovation Solution
The proposed solution involves a mesh block with first and second number generators producing pseudo-random numbers, which are compared using a comparator block to generate an output signal indicating unauthorized activities, triggering protective actions such as disabling functions or erasing memory, and includes a clock tamper detector to ensure continuous alarm signaling even if the clock signal is deactivated.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single random bit generator is used in the mesh block, then the device complexity is reduced, but the tamper resistance and detection reliability are weakened
Solution Approach 1:
The patent implements a second random bit generator that replicates the functionality of the first generator. Both generators produce random bit sequences that are compared by an XOR gate to detect tampering. This copying approach ensures that if one generator is tampered with, the other can still provide a reference for detection, thereby improving reliability without requiring completely new detection mechanisms.
Solution Approach 2:
The patent divides the random bit generation function into two separate generators operating in parallel within the mesh block. Each generator independently produces random bits that are then compared. This segmentation allows the system to detect local tampering attempts on individual generators or their output lines, as any discrepancy between the two generators' outputs will trigger an alarm signal.
2Ease of operation
If mesh wires are made visible or accessible for testing, then the ease of operation and debugging are improved, but the security against reverse engineering and unauthorized access is compromised
Solution Approach 1:
The patent employs a conformal coating as a protective layer over the mesh wires and critical circuit portions. This thin film coating makes the underlying circuitry invisible and inaccessible without removing the coating, thereby preventing reverse engineering and unauthorized access while maintaining the structural integrity and functionality of the protected elements.
Solution Approach 2:
The patent transforms the potential harm of having accessible mesh wires (security vulnerability) into a benefit by implementing active tamper detection. The mesh wires are equipped with random bit generation and comparison circuits that actively monitor for unauthorized access or manipulation. Any attempt to access or modify the mesh wires triggers an alarm, converting the accessibility into a detectable event that can be used to enhance security through continuous monitoring and alarm signaling.
3Use of energy by moving object
If the clock signal can be deactivated to stop operation, then the energy consumption is reduced, but the continuous alarm signaling capability is compromised
Solution Approach 1:
The patent implements a clock tamper detector that dynamically responds to clock signal status. When the clock signal is deactivated, the detector automatically triggers an alarm condition, preventing the system from entering a low-power state that would compromise security monitoring. This dynamic behavior ensures that energy-saving modes cannot be activated without first triggering a security alarm, thereby maintaining continuous alarm capability while allowing energy reduction only under secure conditions.
Data Source
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AI summary
An apparatus includes a mesh block, a first number generator configured to generate a first number, a second number generator configured to generate a second number, and a comparator block configured to compare the first number with the second number and generate an output signal from the mesh block. The output signal indicates an occurrence of an unauthorized activity on the mesh block.