Protecting DSP circuits through obfuscation

This paper presents a novel approach to protect digital signal processing (DSP) circuits through obfuscation by using high-level transformations. The goal is to design DSP circuits that are harder to reverse engineer. High-level transformations of iterative data-flow graphs have been exploited for area-speed-power tradeoffs. This is the first attempt to develop a design flow to apply high-level transformations that not only meet these tradeoffs but also simultaneously obfuscate the architectures both structurally and functionally. Several modes of operations are introduced for obfuscation where the outputs are either meaningful from a signal processing point of view, but functionally incorrect, or non-meaningful. Experimental results show that the proposed methodology only introduces relatively small overhead, while a high level of obfuscation is achieved. For instance, the area overhead for a (3l)th-order IIR filter benchmark is only 17.7% with a 128-bit configuration key.