Characterizing Corruptibility of Logic Locks using ATPG

The outsourcing of portions of the integrated circuit design chain, mainly fabrication, to untrusted parties has led to an increasing concern regarding the security of fabricated ICs. To mitigate these concerns a number of approaches have been developed, including logic locking. The development of different logic locking methods has influenced research looking at different security evaluations, typically aimed at uncovering a secret key. In this paper, we make the case that corruptibility for incorrect keys is an important metric of logic locking. To measure corruptibility for circuits too large to exhaustively simulate, we describe an ATPG-based method to measure the corruptibility of incorrect keys. Results from applying the method to various circuits demonstrate that this method is effective at measuring the corruptibility for different locks.