Watermarking for IP protection through template substitution at logic synthesis level

Functionality preservation and area-time overhead are two major concerns of VLSI designers when the watermarking technique is used to protect their Intellectual Property. For a given technology library and a logically synthesized circuit, replacing cells with the templates of the same function will not alter the topology and original function of the circuit but the performances of some datapaths may be affected. If the resultant circuit can still satisfy the synthesis constraints with an acceptably low overhead, watermarking through template substitution at logic synthesis level is feasible. In this paper, we propose an algorithm to select appropriate cells for the replacement to realize the watermarking scheme. The method is tested on a set of combinational MCNC benchmarks. The results show that this watermarking process can provide a sufficiently strong proof of authorship with trivial area overhead.