Gate camouflaging-based obfuscation

Circuit camouflaging is a layout-level technique to protect VLSI design from being attacked by reverse engineering. It hides design information by configurable logic units that can be configured to perform different functionalities with identical looks to the attackers. In this chapter, after introducing the primitive for gate camouflaging-based obfuscation, we analyze its vulnerability to one specific attack based on circuit partitioning. We then elaborate this attack and discuss two practical countermeasure methods. We explain that the security of gate camouflaging-based obfuscation not only depends on the number of gates being obfuscated, but also which gates we select for obfuscation and the number of different functionalities these gates can implement. As an example, we show how to perform a multiplexer-based gate camouflaging.