NoBALL: A Novel BDD-based Attack against Logic Locking

In modern System-on-Chip (SoC) design, dependence on offshore fabrication has increased manyfold. This empowers SoC designers to meet stringent time-to-market demands. However, it also brings rogue entities into play, possessing security threats like IP piracy, counterfeiting and overbuilding. Several countermeasures have been proposed to thwart these threats. Among all, logic locking has been the most coveted. Logic locking is a design-for-trust technique which conceals the underlying functionality of the design to be protected by adding extra key-controlled gates. This work proposes a novel attack called NoBALL on logic locked designs using their Binary Decision Diagram (BDD) representation. We identify specific properties from the locked design’s BDD and perform intuitive intersection operations in order to identify the correct keys. Experimental analysis highlights that the current version of the attack can act as an alternative to the SAT attack and can even outperform it in some cases. Our attack can also be combined with SAT attack to form a more robust attack in future.