A Security Analysis of Circuit Clock Obfuscation

Key-based circuit obfuscation or logic-locking is a technique that can be used to hide the full design of an integrated from untrusted foundry end-user. The based on creating ambiguity in original by inserting “key” input bits into such unintelligible absent correct secret key. Clock signals have traditionally been avoided locking order not corrupt timing behavior locked circuit. In this paper, we explore case where clock signal itself may obfuscated ambiguating its frequency pattern. Along with discussing formal notions security context, present practical ways deobfuscate designs using techniques multi-rate model-checking. We experimental data deobfuscation runtime set sequential benchmark circuits. Our results show naive random provide more per overhead than traditional keyed-gate insertion. discuss how attractive choice for special are inherently multi-clock/asynchronous.