OSHDA: A Containerized CAD Tool for the Design and Analysis of Behavioral FSM Logic Locking

Abstract

This paper introduces the Open-source Secure Hardware Design and Analysis (OSHDA) toolchain for the logic locking of finite-state machines (FSMs) at the behavioral level. OSHDA's FSM obfuscation method is based on the recently developed State Permutation Logic Locking (SPeLL) algorithm which obfuscates the behavioral transition graph of the FSM, thus avoiding the use of dummy states and reducing exposure to reverse engineering attacks. In addition to implementing the SPeLL algorithm, the toolchain implements a full logic synthesis flow, including the evaluation of the gate-level SPeLL hardware overhead for both FPGA and ASIC designs. In particular, OSHDA enables the automation of trade-off analysis between the strength of SPeLL security and its hardware overhead. The paper further describes attempted attacks on SPeLL using state-of-the-art de-obfuscation tools and identifies research gaps in behavioral de-obfuscation that must be addressed before one can successfully de-obfuscate SPeLL. OSHDA comes with its own scripting subsystem for augmenting its analysis, adding de-obfuscation methods, and integrating physical design tools. Finally, OSHDA is deployed as a hardware security microservice using the Docker framework.