  Outsourcing in semiconductor industry opened up venues for faster and
cost-effective chip manufacturing. However, this also introduced untrusted
entities with malicious intent, to steal intellectual property (IP),
overproduce the circuits, insert hardware Trojans, or counterfeit the chips.
Recently, a defense is proposed to obfuscate the scan access based on a dynamic
key that is initially generated from a secret key but changes in every clock
cycle. This defense can be considered as the most rigorous defense among all
the scan locking techniques. In this paper, we propose an attack that remodels
this defense into one that can be broken by the SAT attack, while we also note
that our attack can be adjusted to break other less rigorous (key that is
updated less frequently) scan locking techniques as well.
