Integrated Photocurrent Detection Circuits for Laser Attack Response
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Solution Overview
Problem
Existing countermeasures against laser-based attacks on integrated circuits, such as physical barriers and redundancy, face limitations in compatibility, performance impact, and cost, while being vulnerable to increased light intensity and attacks affecting redundant paths.
Innovation Solution
The implementation of photocurrent detection circuits within integrated circuits, comprising asymmetrically sized N-type and P-type MOS devices, forming logic circuits that detect changes in logic states induced by radiation, allowing for the identification of photocurrents and triggering countermeasures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If physical barriers (metal shields) are used to block laser attacks, then protection against radiation is improved, but compatibility with IC fabrication limits and circuit performance is worsened
Solution Approach 1:
The patent replaces physical mechanical barriers (metal shields) with an electrical detection system. Photodetector circuits integrated within the IC detect laser-induced photocurrents, and control logic responds by disabling affected circuits. This substitution eliminates fabrication compatibility issues while maintaining protection capability.
2Object-affected harmful factors
If device architectures with small sensitive volumes are used, then resistance to laser attacks is improved, but other aspects of device performance are compromised
Solution Approach 1:
The patent implements feedback by continuously monitoring circuits for laser-induced photocurrents using photodetectors. When an attack is detected, the control logic responds by disabling the affected circuit, preventing performance degradation. This feedback mechanism allows normal operation under typical conditions while providing protection when needed.
Solution Approach 2:
The patent introduces photodetector circuits as intermediary elements that detect laser attacks before they can significantly impact device performance. These photodetectors act as mediators between the external laser threat and the protected circuit, enabling early detection and response without compromising normal device operation.
3Measurement precision
If redundancy is used to detect corrupted circuit operation, then detection capability is improved, but silicon area cost and vulnerability to simultaneous attacks are worsened
Solution Approach 1:
The patent makes photodetector circuits universal by integrating them directly into the logic circuits they protect. The same photodetector that detects attacks on a specific logic gate also contributes to overall system security. This multi-functional integration reduces the total silicon area required compared to separate redundant detection circuits.
4Measurement precision
If redundancy is used to detect corrupted circuit operation, then detection capability is improved, but cost and vulnerability to attacks affecting redundant paths are worsened
Solution Approach 1:
The patent applies local quality by placing photodetectors at specific vulnerable locations within the circuit rather than using uniform redundancy throughout. Each photodetector is strategically positioned to monitor critical logic gates, providing targeted protection where it is most needed while reducing overall vulnerability to simultaneous attacks.
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
These circuits effectively detect radiation-induced photocurrents, enabling timely countermeasures to prevent data corruption and system vulnerabilities, while being sensitive to the same radiation wavelengths as the protected circuitry and maintaining predictable responses.
Implementation Method 1
Pulsed lasers provide a convenient and easily controlled method for introducing such faults by creating transient currents in PN junctions or device channels through the photo-electric effect
Data Source
AI summary
Various embodiments include integrated approaches to detecting attempts to breach system-level or chip-level security using photo-generated currents induced by lasers or other radiation sources. Various embodiments integrate photo-detection circuits with a secure processor or other circuit in such a manner that the response to a security attack is fast enough to prevent loss of secure or private information are described. Various embodiments include circuits capable of providing a permanent record of photocurrent detection.