Post-satisfiability Era: Countermeasures and Threats

Starting in 2005, numerous logic locking techniques have been introduced in the literature, each trying to introduce a new countermeasure against the existing threat models. On the other side, starting in 2012, the attacks on logic locking started to be developed and sophisticated, each trying to investigate the security holes in the existing countermeasures, leading to a scenario to eventually break them. This chapter will provide a chronological holistic review of these techniques, either defenses or attacks, to capture the most benefit from the existing techniques for defense/attack and illuminate the need for and give direction to future research studies on this topic. This chapter specifically serves as a guide to quickly navigate and identify the state of the art that should be considered and investigated for further studies on logic locking techniques, helping IP vendors, SoC designers, and researchers to be informed of the principles, fundamentals, and properties of logic locking.