Heuristics reveal hidden hardware Trojans in chip designs
Demystifying Gate-Level Localization of RTL Trojans
Hardware ArchitectureCryptography and Security
Summary
Hardware Trojans are secret changes added to computer chips that can cause problems or leak information. These Trojans are hard to find after chips are changed from their original design form. The authors found that Trojans keep certain patterns even after these changes, allowing simple rules to detect and locate them effectively. Their method, called LoRD, works better than advanced machine learning methods without needing extra data or training.
What this means in practice
- •For hardware verification teams: Detect and locate malicious modifications in chip designs after synthesis without needing golden reference chips.
- •For integrated circuit security engineers: Use structural patterns to find concealed hardware Trojans in gate-level netlists during security assessments.
Authors
Navid Nader Tehrani, Azadeh Davoodi, Rasit Onur Topaloglu
Abstract
Hardware Trojans are malicious modifications that compromise functionality or leak sensitive data. They pose a severe threat, particularly when inserted at the Register Transfer Level (RTL). After synthesis, these Trojans are often concealed by optimizations in gate-level netlists. Recent efforts, including the ICCAD 2025 contest, emphasize golden-chip-free detection using machine learning (ML) on labeled netlists. In this work, we show that RTL Trojans exhibit stable structural and signal-flow patterns post-synthesis, enabling effective detection through targeted heuristics rather than generic ML feature learning. We propose LoRD, a lightweight heuristic-based approach that exploits these distinctive subgraph signatures, achieving near-perfect detection and localization on the contest testcases. Com- pared to a transformer-based ML baseline and top five teams, LoRD achieves on-average a score of 2.957 (out of 3) for Trojan- implanted designs without the data and tuning overhead.