Improving logic obfuscation via logic cone analysis

Logic obfuscation can protect designs from reverse engineering and IP piracy. In this paper, a new attack strategy based on applying brute force iteratively to each logic cone is described and shown to significantly reduce the number of brute force key combinations that need to be tried by an attacker. It is shown that inserting key gates based on MUXes is an effective approach to increase security against this type of attack. Experimental results are presented quantifying the threat posed by this type of attack along with the relative effectiveness of MUX key gates in countering it.