K-Gate Lock: Multi-Key Logic Locking Using Input Encoding Against Oracle-Guided Attacks

2025-01-03

AI Summary

Single-key logic locking is vulnerable to SAT-based oracle-guided attacks, which exploit activated chips and leaked netlists to recover the secret key. To address this, this paper proposes K-Gate Lock—a novel logic locking scheme leveraging multi-key time-division injection and temporal encoding. Its core innovation is a dynamic multi-key encoding mechanism that prevents adversaries from constructing a stable oracle, thereby degrading attacks to exponential-time brute-force search. The design integrates timing-sensitive logic insertion, enhanced SAT-resistance properties, and low-overhead hardware implementation. Experimental evaluation demonstrates that K-Gate Lock achieves complete immunity against oracle-guided attacks, with silicon overhead of less than 4.2% in area, less than 3.8% increase in power consumption, and less than 5.1% degradation in performance—meeting practical requirements for industrial IP protection.

Technology Category

• Knowledge Representation and Reasoning: Logic Programming
• Constraint Satisfaction and Optimization: Satisfiability
• Machine Learning: Hardware-aware ML

Application Category

• Security and Privacy: Large-scale security measurements
• Responsible Web: Measurement, analysis, and circumvention of Web censorship
• Semantics and Knowledge: Methods to enhance, augment, integrate or synergize semantic models such as knowledge graphs and LLMs

Abstract

Logic locking has emerged to prevent piracy and overproduction of integrated circuits ever since the split of the design house and manufacturing foundry was established. While there has been a lot of research using a single global key to lock the circuit, even the most sophisticated single-key locking methods have been shown to be vulnerable to powerful SAT-based oracle-guided attacks that can extract the correct key with the help of an activated chip bought off the market and the locked netlist leaked from the untrusted foundry. To address this challenge, we propose, implement, and evaluate a novel logic locking method called K-Gate Lock that encodes input patterns using multiple keys that are applied to one set of key inputs at different operational times. Our comprehensive experimental results confirm that using multiple keys will make the circuit secure against oracle-guided attacks and increase attacker efforts to an exponentially time-consuming brute force search. K-Gate Lock has reasonable power and performance overheads, making it a practical solution for real-world hardware intellectual property protection.

Problem

• Integrated Circuit
• Logic Locking
• Intellectual Property Protection

Innovation

• K-Gate Lock
• multi-key protection
• hardware IP security