Security analysis of logic obfuscation

Due to globalization of Integrated Circuit (IC) design flow, rogue elements in the supply chain can pirate ICs, overbuild ICs, and insert hardware trojans. EPIC [1] obfuscates the design by randomly inserting additional gates; only a correct key makes the design to produce correct outputs. We demonstrate that an attacker can decipher the obfuscated nctlist, in a time linear to the number of keys, by sensitizing the key values to the output. We then develop techniques to fix this vulnerability and make obfuscation truly exponential in the number of inserted keys.