On Improving the Security of Logic Locking

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 locks 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 locked netlist, in a time linear to the number of keys, by sensitizing the key-bits to the output. We then develop techniques to fix this vulnerability and make an attacker's effort truly exponential in the number of inserted keys. We introduce a new security metric and a method to deliver strong logic locking.