Logic Encryption: This Time for Real

2025-11-30

AI Summary

Existing logic locking techniques struggle to simultaneously obscure both circuit structure and functionality. To address this, this paper proposes a novel logic encryption (LE) methodology for IP protection that deeply integrates standardized cryptographic primitives with randomized key-bit assignment, adopting a “correct-by-construction” paradigm to achieve end-to-end logic-level encryption and secure synthesis at the system-level synthesis stage. Crucially, the approach directly encrypts logic functions via encoding—rather than merely inserting external lock registers—thereby concurrently obfuscating structural topology and behavioral semantics. Experimental evaluation demonstrates that the proposed scheme significantly enhances resilience against oracle-free attacks, outperforming state-of-the-art methods under diverse threat models including reverse engineering, IP theft, and side-channel analysis. Moreover, it reduces area overhead and is fully open-sourced.

Technology Category

• Machine Learning: Privacy
• Knowledge Representation and Reasoning: Logic Programming
• Computer Vision: Low Level & Physics-based Vision

Application Category

• Security and Privacy: Applications of cryptography
• Responsible Web: Measurement, analysis, and circumvention of Web censorship
• Economics, Online Markets and Human Computation: Architectures and workflows that use LLMs for crowd work

Abstract

Modern circuits face various threats like reverse engineering, theft of intellectual property (IP), side-channel attacks, etc. Here, we present a novel approach for IP protection based on logic encryption (LE). Unlike established schemes for logic locking, our work obfuscates the circuit's structure and functionality by encoding and encrypting the logic itself. We devise an end-to-end method for practical LE implementation based on standard cryptographic algorithms, key-bit randomization, simple circuit design techniques, and system-level synthesis operations, all in a correct-by-construction manner. Our extensive analysis demonstrates the remarkable efficacy of our scheme, outperforming prior art against a range of oracle-less attacks covering crucial threat vectors, all with lower design overheads. We provide a full open-source release.

Problem

• Protects circuits from reverse engineering and IP theft
• Encrypts logic to obfuscate circuit structure and function
• Implements practical logic encryption with low design overhead

Innovation

• Encrypts logic itself for circuit obfuscation
• Uses cryptographic algorithms and key-bit randomization
• Ensures correct-by-construction with low design overhead