Physical Design Obfuscation of Hardware: A Comprehensive Investigation of Device- and Logic-Level Techniques

TL;DR

This paper systematically investigates physical design obfuscation techniques at device and logic levels to enhance hardware security against reverse engineering, providing a taxonomy, review, and new methods.

Contribution

It offers a comprehensive categorization of physical obfuscation techniques, reviews existing methods, and introduces new device and logic-level obfuscation techniques with feasibility and detection analysis.

Findings

Physical obfuscation techniques vary across design stages.

A new taxonomy aids systematic treatment of obfuscation methods.

Proposed techniques show potential for effective hardware security.

Abstract

The threat of hardware reverse engineering is a growing concern for a large number of applications. A main defense strategy against reverse engineering is hardware obfuscation. In this paper, we investigate physical obfuscation techniques, which perform alterations of circuit elements that are difficult or impossible for an adversary to observe. The examples of such stealthy manipulations are changes in the doping concentrations or dielectric manipulations. An attacker will, thus, extract a netlist, which does not correspond to the logic function of the device-under-attack. This approach of camouflaging has garnered recent attention in the literature. In this paper, we expound on this promising direction to conduct a systematic end-to-end study of the VLSI design process to find multiple ways to obfuscate a circuit for hardware security. This paper makes three major contributions. First, we provide a categorization of the available physical obfuscation techniques as it pertains to various design stages. There is a large and multidimensional design space for introducing obfuscated elements and mechanisms, and the proposed taxonomy is helpful for a systematic treatment. Second, we provide a review of the methods that have been proposed or in use. Third, we present recent and new device and logic-level techniques for design obfuscation. For each technique considered, we discuss feasibility of the approach and assess likelihood of its detection. Then we turn our focus to open research questions, and conclude with suggestions for future research directions.