On Custom LUT-based Obfuscation

Logic obfuscation yields hardware security against various threats, such as Intellectual Property (IP) piracy and reverse engineering. Evolving Boolean satisfiability (SAT) attacks have challenged the hardware security assurance rendered by various obfuscation methods. Recent works have centered on using re-configurable components such as Look-Up-Tables (LUTs) to enhance resiliency against attacks. Resiliency against SAT-attack is guaranteed when the size of LUT (number of inputs) is large. However, this incurs significant power, area and performance overheads. To address this challenge, this work proposes logic encryption based on customized LUT to make this practical. We propose two variants of the customized LUT based obfuscation: LUT+MUX based obfuscation, securing the design through routing obfuscation by MUX(multiplexer) and logic obfuscation of LUTs; and LUT+LUT based obfuscation, benefiting from LUT based obfuscation reinforced with additional logic/routing obfuscation. We evaluate the hardware security and overheads of the proposed two variants of customized LUT-based obfuscation on various benchmarks. Proposedcustomized LUT-based obfuscation breaks the security, power, and area trade-offs. The proposed solution is shown to be robust against SAT-attacks and power analysis-based side-channel attacks with8×reduced area and 3×reduced power on an average compared tostate-of-the-art LUT-based obfuscation.