Ring Oscillator Trojan Detection in Integrated Circuits
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Solution Overview
Problem
Current Design-For-Trust (DFTr) techniques for detecting Trojans in integrated circuits (ICs) are ineffective when Trojans are power-gated, assume specific Trojan models, and fail to account for process variations, leading to false negatives and high hardware overhead.
Innovation Solution
The implementation of ring oscillator (RO) based DFTr techniques, which involve selecting paths with unsecured gates, embedding ring oscillators, determining input patterns to activate them, and measuring frequencies to detect Trojans by comparing against golden frequencies adjusted for process variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If power analysis based Trojan detection methods are used, then detection capability is improved, but effectiveness decreases when Trojans are power-gated
Solution Approach 1:
The patent changes the detection parameter from power consumption to oscillation frequency. By measuring frequency changes in ring oscillators instead of power consumption, the method becomes effective against power-gated Trojans that would otherwise be undetectable through power analysis alone.
Solution Approach 2:
The patent replaces the electrical measurement approach (power consumption measurement) with a temporal measurement approach (frequency/period measurement). This substitution allows detection of Trojans that do not consume additional power by measuring time-based characteristics instead.
2Measurement precision
If statistical techniques are used to overcome process variations, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent uses a simple frequency threshold comparison rather than complex statistical analysis. By measuring whether the frequency falls within an expected range, the method achieves sufficient detection accuracy without implementing sophisticated statistical techniques, thus maintaining low device complexity.
Solution Approach 2:
The patent employs simple ring oscillator structures that are inexpensive and easy to implement. These oscillators serve as disposable detection elements that provide the necessary measurement capability without requiring complex or expensive detection infrastructure.
3Reliability
If path delay measurement techniques are used, then Trojan detection capability is improved, but hardware overhead increases
Solution Approach 1:
The patent merges the Trojan detection function with the existing ring oscillator structures already present in the IC. By utilizing these existing oscillators for dual purposes (normal operation and Trojan detection), the method achieves detection capability without adding significant hardware overhead.
Solution Approach 2:
The patent makes the ring oscillators multi-functional by using them both for their original purpose and for Trojan detection. This universal utilization of existing structures eliminates the need for separate dedicated detection hardware, thereby reducing overall hardware overhead.
Data Source
AI summary
A ring oscillator (RO) based Design-For-Trust (DFTr) technique is described. Functional paths of integrated circuit (IC) are included in one or more embedded ROs by (1) selecting a path in the IC, based on path selection criteria, that has one or more unsecured gates, and (2) embedding one or more ROs on the IC until a stop condition is met. An input pattern to activate embedded RO is determined. Further, a golden frequency which is a frequency at which the embedded RO oscillates, and a frequency range of the embedded RO are determined. A Trojan in the IC may be detected by activating the embedded RO (by applying the input pattern), measuring a frequency at which the embedded RO oscillates, and determining whether or not a Trojan is present based on whether or not the measured frequency of the RO is within a predetermined operating frequency range of the RO.